JP4906555B2 - Sirocco fan and air conditioner - Google Patents

Description

  The present invention relates to a sirocco fan and an air conditioner that have reduced noise and improved air blowing characteristics.

  Conventionally, in a sirocco fan, it is known that a reverse flow phenomenon occurs in which a part of the air flow blown from a spiral scroll flows from the outside of the fan toward the inside of the fan. When the reverse flow occurs, a collision with the suction air flow occurs, so that not only the amount of air blown but also the noise increases. Therefore, in order to suppress such a backflow phenomenon, a device has been devised such as changing the shape of the bell mouth forming the scroll suction port into regions in the circumferential direction (see, for example, Patent Document 1). Moreover, the example which provides an auxiliary tongue part so that it may protrude from a tongue part other than a tongue part is also proposed (for example, refer patent document 2).

JP-A-9-126193 (page 4-5, FIGS. 1 and 2) JP 2006-138268 A (page 4, FIG. 1, FIG. 3)

  On the other hand, in a conventional air conditioner equipped with a sirocco fan, the amount of blown air from the sirocco fan at a predetermined noise level is small and the performance of the heat exchanger is reduced. In order to suppress the decrease in COP and increase the blowing air volume of the sirocco fan, there is a problem that the noise level increases and the user feels uncomfortable.

In view of the above-described problems, the present invention provides a sirocco fan capable of increasing the air volume at a predetermined noise level, in other words, reducing the noise value and the rotational speed when obtaining the predetermined air volume, and an air conditioner including the sirocco fan. The purpose is to provide.
Another object of the present invention is to devise the shape of the scroll to suppress the backflow phenomenon and reduce the noise value while maintaining a predetermined air volume.

A sirocco fan according to the present invention is a sirocco fan that includes a scroll, a fan body that is rotatably disposed in the scroll, and has a large number of blades arranged in a cylindrical shape, and a motor that rotationally drives the fan body. ,
The scroll has a contour which is formed in a spiral shape, and a substantially parallel two straight portions on its outer, one of the straight portions of said straight portion being connected to the discharge port of the scroll, the motor The rotation axis is positioned closer to the straight line portion closer to the tongue portion of the scroll.

According to the present invention, in a sirocco fan comprising a scroll, a fan main body having a large number of blades arranged rotatably in the scroll and arranged in a cylindrical shape, and a motor for rotationally driving the fan main body, It has a contour which is formed in a spiral shape, and two straight portions substantially parallel to the contour of that, one of the straight portions of said straight portion being connected to the discharge port of the scroll, the motor By positioning the rotary shaft closer to the straight line portion closer to the tongue of the scroll, the air volume at the time of predetermined noise can be increased, and in the case of an air conditioner, COP can be improved.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Embodiment 1 FIG.
1A and 1B are a schematic plan view (a) and a side view (b) showing an internal configuration of an indoor unit of an air-conditioning apparatus including a sirocco fan according to Embodiment 1 of the present invention.
In FIG. 1, reference numeral 10 denotes an indoor unit that constitutes an indoor air conditioner, and exchanges heat with a pair of sirocco fans 1, a fan motor 2 that rotationally drives the sirocco fans 1 at the same time, and air blown from the sirocco fan 1. The heat exchanger 3 to perform is provided. The sirocco fan 1 includes a spiral scroll 6 and a fan body that is rotatably disposed in the scroll 6 and has a large number of blades arranged in a cylindrical shape. In the figure, 4 is an air suction port, 5 is a cold or warm air outlet, 7 is a rotating shaft of the fan motor 2, and 8 is a tongue.

The indoor unit 10 includes a refrigerant refrigeration circuit including a compressor, a condenser, an expansion valve, and an evaporator (not shown), and is configured to perform indoor cooling or heating. As an example of the specifications in the first embodiment, the sirocco fan 1 has a fan diameter of 160 mm, a width of 190 mm, and the number of blades of 40, and the heat exchanger 3 includes 12 stages of heat transfer tubes. The row pitch of the heat transfer tube is 12.7 mm, the step pitch is 20.4 mm, the length in the axial direction of the heat transfer tube is 700 mm, and the ventilation resistance ΔP1 = 23.1V ^1.3 [Pa] (V: speed [m / s]) It has become. The indoor unit 10 has a depth of 680 mm, a height of 210 mm, and a width of 960 mm.

  The indoor air is sucked from the suction port 4 of the indoor unit 10 and further sucked in the axial direction from the suction port of the scroll 6. Air to which dynamic pressure and static pressure are applied by a cylindrical blade row rotating in the scroll 6 by the fan motor 2 is blown out from an outlet opening in the air passage of the indoor unit 10 and installed in the air passage. The heat is exchanged with the heat exchanger 3 and is blown out into the room through the blowout port 5 as cold air or warm air.

FIG. 2 is a diagram showing the positional relationship between the rotation axis of the motor and the center of the bell mouth in Embodiment 1 of the present invention, where point O is the center of the bell mouth 9 and point P is the center of the rotation axis of the motor 2 (fan Center of rotation).
The scroll 6 according to the present embodiment has two linear portions 12 and 13 that are substantially parallel on the spiral outer shape, and the rotation axis of the fan motor 2 is closer to the linear portion 12 closer to the tongue portion 8 of the scroll 6. The center of 7 is arranged. In other words, the fan rotation center P is decentered with respect to the bell mouth center O, and the decentered position is set closer to the straight portion 12 closer to the tongue portion 8.

Table 1 shows the noise value and the rotation speed when the length of the OP is 0 mm and 2 mm when the air flow rate of the indoor unit is 16 m ³ / min.

  From Table 1, when OP is set to 2 mm, the noise value and the rotational speed can be reduced.

Next, the reason will be described. Table 2 shows the maximum airflow between the blades when the OP length is 0 mm and the rotation speed is 1103 rpm, and when the OP length is 2 mm and the rotation speed is 1092 rpm. Both airflows are 16 m ³ / min.

From Table 2, the maximum airflow between the blades is smaller when the OP length is 2 mm. The sound pressure energy is proportional to the sixth power of the speed, and the noise value is expressed by the following equation: SPL = ₁₀ log ₁₀ (p / p ₀ ) ² [dB]
p: Sound pressure energy [Pa], p ₀ : 2 × 10 ⁻⁵ [Pa]
Therefore, in order to reduce the noise value, that is, to reduce the sound pressure energy, it is effective to reduce the maximum speed, and when the airflow distribution between the blades is not uniform like a sirocco fan, It is recommended to reduce the maximum airflow between the blades.

Embodiment 2. FIG.
FIG. 3 is a diagram showing a scroll shape according to the second embodiment of the present invention. However, in the present embodiment, the bell mouth center and the fan rotation center are made to coincide with each other (when the eccentricity is zero).
The scroll 6 has two linear portions FH and EB that are substantially parallel to each other in a spiral shape. The shortest distance between the two substantially parallel straight lines is CG, and is parallel to the linear portions FH and EB of the scroll. The point of intersection of the parallel line passing through the mouse center O and the scroll outline is point A, the point on the scroll outline where the distance between the scroll outline and the fan rotation center O is the maximum, the point B, and the scroll straight line passing through the fan rotation center O. Assume that the intersections of the perpendiculars to the portions FH and EB and the linear portions FH and EB of the scroll are points C and G, the fan radius is R, and the angle between the line segment OA and the line segment OB is θ.

The curve FGHABCE representing the conventional scroll shape is a logarithmic spiral, 2 R / CG is about 0.68, and the fan diameter is smaller than 0.72 ≦ 2 R / CG ≦ 0.82 of the present embodiment. The number of rotations required to obtain a predetermined air volume increases.
On the other hand, when 2 R / CG is increased, the number of revolutions required to obtain a predetermined air volume is reduced, but the line segment EB approaches the fan, the air volume is concentrated between the blades close to the line segment EB, and the noise level is large. Become.
Therefore, when 2 R / CG is increased and the curve AB is separated from the fan rather than the logarithmic spiral, the airflow between the blades near the curve AB increases, and the airflow between the blades near the line segment EB decreases accordingly.

Table 3 shows that the conventional scroll shape and 2 R / CG is 0.68 (CASE 1), 2 R / CG = 0.76, (OC-R) /R=0.375, θ = 60 °. (CASE 2) shows the noise value and the number of rotations when the air flow rate of the indoor unit is 16 m3 / min.

As shown in Table 3, the sirocco fan of the present embodiment having a scroll shape with 2 R / CG = 0.76, (OC-R) /R=0.375, and θ = 60 ° is more conventional. By making 2 R / CG larger and separating the curve AB from the fan than the sirocco fan having a scroll shape composed of a logarithmic spiral, the noise value and the rotational speed can be reduced.

  As for the upper limit value of (OC-R) / R, if the distance between the linear portion EB of the scroll 6 and the fan outer peripheral end is larger than 0.45, the air flow rate decreases and the noise value increases. OC-R) /R≦0.45.

Embodiment 3 FIG.
FIG. 4 shows a perspective view when the fan main body 11, the fan motor 2, and the motor support base 14 are combined, FIG. 5 shows a perspective view when the motor support base 14 does not have the ventilation port 15, and FIG. The perspective view in case the ventilation base 15 exists in the support stand 14 is shown.
Table 4 shows the noise value and the number of rotations with and without the air vent of the motor support base when the air flow rate of the indoor unit is 16 m ³ / min.

According to Table 4, when the motor support base has a ventilation hole, the rotation speed is hardly changed, but the noise value is small. This is because, when the motor support base 14 does not have the ventilation port 15, the static pressure fluctuation generated from the fan propagates to the motor support base 14, and the static pressure fluctuation occurs on the wall surface of the motor support base 14, resulting in noise. When the motor support base 14 has the air vent 15, static pressure fluctuations generated from the fans cancel each other out in the space near the motor support base 14, and the static pressure fluctuation of the wall surface of the motor support base 14 is suppressed. It is.
Further, since the rotation speed hardly changes, it can be seen that even if the ventilation hole 15 is provided in the motor support base 14, the suction space of the sirocco fan does not change. Note that the configuration in which the ventilation hole 15 is provided in the motor support base 14 as described above may be combined with the configuration in the first embodiment or the second embodiment described above.

Embodiment 4 FIG.
FIG. 7 shows a schematic perspective view when ribs 16 are provided at both ends of the scroll tongue 8 in the present embodiment, and FIG. 8 shows a schematic side view thereof.
The rib 16 has a substantially rectangular parallelepiped shape, the point farthest from the fan main body 11 of the rib 16 is the point X, the point farthest from the fan main body 11 of the arc portion of the tongue 8 is the point Y, and the most from the fan main body 11 of the rib 16 A close point is defined as a point Z, and a line segment XY ≦ XZ.
FIG. 9 shows a velocity component perpendicular to the outlet 18 when the rib 16 is not provided. In FIG. 9, a reverse flow region 20 indicated by a dotted line of the outlet 18 represents a flow from the outside to the inside of the fan. FIG. 10 shows streamlines when smoke is introduced from, for example, a line segment 21 on the suction port 17 in order to verify the backflow phenomenon.

Table 5 shows the noise value and the number of rotations when there is a rib and when there is no rib when the blowout air volume of the indoor unit is 16 m ³ / min.

As shown in Table 5, the noise value and the rotational speed can be reduced by providing the rib. The reason for this is that when there is no rib and there is a flow resistor such as a heat exchanger, the greater the ventilation resistance of the resistor, the more the wind flows from the blowout port 18 at the blowout port 18 of the sirocco fan as shown in FIG. A reverse flow phenomenon toward the inside of the fan occurs, which causes an increase in noise value and rotation speed. As shown in FIG. 10, the wind blown from between the wings on the main plate side is directed to both ends of the scroll along the scroll and does not flow toward the outlet 18 near the both ends of the tongue 8. It flows into the gap between the portion 8 and the fan main body 11, and further flows into the space between the blades. The flow 22 is blown out from between the blades on the main plate side and blown out of the scroll. When such a flow occurs, the static pressure fluctuation of the wall surface increases near both ends of the tongue, a flow that passes through the blades multiple times occurs, and the amount of air circulating inside the fan increases, thereby increasing the airflow between the blades. Therefore, the static pressure fluctuation on the blade surface also increases, and the noise value increases.
On the other hand, when the rib 16 is present, the wind blown from between the wings on the main plate side is directed to both ends of the scroll along the scroll, and does not flow toward the outlet 18 near the both ends of the tongue portion 8. Since the flow rate flowing into the gap between the portion 8 and the fan main body 11 can be reduced, the noise value and the rotational speed can be reduced as compared with the case where there is no rib as shown in Table 5. The width of the rib 16 is suitably in the range of 5 to 10 mm. Further, the configuration in which the ribs 16 of the present embodiment are provided may be combined with any of the configurations of the first to third embodiments.

It is the typical top view (a) and side view (b) which show the internal structure of the indoor unit of the air conditioning apparatus which comprises the sirocco fan in Embodiment 1 of this invention. 6 is a diagram illustrating a positional relationship between the center of the bell mouth and the center of the rotation shaft in the first embodiment. FIG. FIG. 10 is a diagram illustrating a scroll shape in a second embodiment. FIG. 9 is a perspective view illustrating an assembly of a motor support base, a fan motor, and a fan main body according to Embodiment 3. It is a perspective view of the motor support stand of FIG. It is a perspective view at the time of providing a ventilation opening in a motor support stand. It is a schematic diagram at the time of providing a rib in the both ends of the tongue part of the scroll in Embodiment 4. FIG. It is a typical side surface of the rib of FIG. It is a figure showing the speed distribution in the blower outlet of a sirocco fan. It is a figure showing the backflow phenomenon in the blower outlet of a sirocco fan.

Explanation of symbols

  1 Sirocco fan, 2 fan motor, 3 heat exchanger, 4 inlet port, 5 outlet port, 6 scroll, 7 rotating shaft, 8 tongue, 9 bell mouth, 10 indoor unit, 11 fan body, 12 linear portion, 13 linear Part, 14 motor support stand, 15 ventilation port, 16 rib, 17 suction port, 18 outlet, 20 reverse flow region, 22 flow.

Claims (5)

In a sirocco fan that includes a scroll, a fan body that is rotatably arranged in the scroll and has a large number of blades arranged in a cylindrical shape, and a motor that rotationally drives the fan body.
The scroll has an outer shape formed in a spiral shape and two linear portions substantially parallel to the outer shape, and one of the linear portions is connected to a discharge port of the scroll, and the motor The sirocco fan is characterized in that the rotation axis of the sirocco is positioned closer to the linear portion closer to the tongue of the scroll. In a sirocco fan that includes a scroll, a fan body that is rotatably arranged in the scroll and has a large number of blades arranged in a cylindrical shape, and a motor that rotationally drives the fan body.
The scroll center is aligned with the fan rotation center, and the scroll has an outer shape formed in a spiral shape and two linear portions substantially parallel to the outer shape, and one of the linear portions. The straight line portion of the scroll is connected to the discharge port of the scroll, and the shortest distance between two substantially parallel straight lines is H, and the intersection of the parallel line parallel to the straight line portion and passing through the bell mouth center O and the scroll outline is marked. A, the intersection point on the scroll outer shape where the distance between the scroll outer shape and the fan rotation center O is the maximum is the point B, and the intersection points between the straight portion passing through the fan rotation center O and the perpendicular to these direct portions are the points C and G, respectively. When the fan radius is R and the angle between the line segment OA and the line segment OB is θ,
A sirocco fan characterized in that 0.72 ≦ 2R / H ≦ 0.82, 0.3 ≦ (OC−R) /R≦0.45, θ ≦ 70 °, and OB ≧ OC. 3. The sirocco fan according to claim 1, wherein a vent hole for suppressing a static pressure fluctuation generated from the fan body is provided on a support base of the motor. According to claim 1 or 2, sirocco fan, wherein said that from the outside of the fan main body is provided for suppressing ribs backflow of the air toward the inside at both ends of the tongue portion of the scroll. An air conditioner comprising the sirocco fan according to any one of claims 1 to 4 .

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