JP2015092073A - Cross-flow fan, and indoor unit of air conditioner provided with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cross-flow fan capable of reducing noises, and to provide an indoor unit of an air conditioner provided with the same.SOLUTION: A cross-flow fan (2) comprises: an impeller (3) including a plurality of blades (31) and rotating in a prescribed rotation direction (D); and a rear guider (4) which has an opposite surface (40) opposite to the impeller (3) in a radial direction. The opposite surface (40) has a closest proximity part (41) which has a closest distance to the impeller (3). On the downstream side in the rotation direction (D) than the closest proximity part (41), in the opposite surface (40), back flow suppression means (5) is provided for suppressing occurrence of the back flow flowing in a direction inverse to the rotation direction (D) through a clearance between the impeller (3) and the closest proximity part (41).

Description

The present invention relates to a crossflow fan and an indoor unit of an air conditioner including the same.

  Conventionally, a cross flow fan is used for an indoor unit of an air conditioner, for example. Patent document 1 is disclosing the air conditioner provided with a crossflow fan. In an air conditioner including such a crossflow fan, it is required to reduce noise.

  For example, in the air conditioner described in Patent Document 2, in order to suppress the turbulence of the air flow in the vicinity of the winding start portion of the rear guider (back scroll), from the winding start portion of the back scroll toward the opposite direction of the rotor rotation direction. An extending vortex stabilizing member is provided. As a result, the vortex center on the back side can be positioned upstream of the winding start portion of the back scroll outside the fan rotor, and as a result, the turbulence of the air flow in the vicinity of the winding start portion of the back scroll is suppressed. It is described that the amount of noise generation can be reduced.

  Patent Document 3 discloses an air conditioner in which a front end portion of a rear guider is brought close to and opposed to an impeller, and a plurality of bump-shaped protrusions are provided further upward from the proximity portion toward the impeller side. ing. It is described that by providing such a bump-shaped protrusion, it is possible to stabilize the blowing static pressure characteristic and improve the blowing performance.

Japanese Patent Laid-Open No. 7-293489 JP 2001-90689 A Japanese Patent Laid-Open No. 10-205798

  However, as shown in FIG. 13, in the gap between the facing surface 140 of the rear guider 104 (back scroll 104) of the cross flow fan 102 and the impeller 3, air flows in a direction opposite to the rotational direction D of the impeller 3. A certain backflow Fr (leakage flow Fr) may occur. Since such a backflow Fr flows in the direction opposite to the rotation direction D of the impeller 3, the relative speed with the impeller 3 increases. Such a backflow Fr passes through the vicinity of the closest portion 141 (the winding start portion S of the rear guider 4) that is the closest to the impeller 3, in the vicinity of the outer edge of the blade 31 of the impeller 3. Abrupt pressure fluctuations occur at every pitch, causing an increase in fan noise.

  The objective of this invention is providing the cross-flow fan which can reduce a noise, and the indoor unit of an air conditioner provided with the same.

  The crossflow fan of the present invention has a plurality of blades (31), and is opposed to the impeller (3) rotating in a predetermined rotation direction (D) and the impeller (3) in the radial direction. A rear guider (4) having an opposing surface (40). The opposing surface (40) has a closest part (41) that is closest to the impeller (3). A gap between the impeller (3) and the closest part (41) is arranged in the rotational direction (41) downstream of the closest part (41) on the facing surface (40) in the rotational direction (D). D) is provided with backflow suppression means (5) that suppresses the occurrence of backflow that is an airflow flowing in the opposite direction.

  In this configuration, since the backflow suppressing means (5) is provided on the opposed surface (40) of the rear guider (4) on the downstream side in the rotational direction (D) with respect to the closest portion (41), the impeller (3) And back flow can be prevented from occurring in the gap between the closest part (41). Thereby, since the pressure fluctuation which arises when a backflow passes the clearance gap between the nearest part (41) and an impeller (3) becomes small, noise can be reduced.

  In the crossflow fan, the backflow suppressing means (5) includes one or a plurality of linear protrusions (51) that protrude toward the impeller (3) and extend linearly in a direction intersecting with the backflow. You may go out.

  In this structure, the linear protrusion part (51) is provided in the downstream of the rotation direction (D) rather than the closest part (41), and the linear protrusion part (51) is on the impeller (3) side. Since it protrudes and extends linearly in a direction intersecting with the backflow, the space between the impeller (3) and the rear guider (4) is directed to the closest part (41) in the direction opposite to the rotational direction (D). Resistance to air flow. As a result, the backflow that passes through the gap between the closest part (41) and the impeller (3) is also less likely to occur.

  In the cross flow fan, it is preferable that the intersecting direction is a direction parallel to the rotation axis (3A) of the impeller (3).

  In this structure, in the space between the impeller (3) and the rear guider (4), with respect to the air flow toward the closest part (41) in the direction opposite to the rotational direction (D), the linear protrusion ( The extending direction of 51) is approximately orthogonal. Therefore, it is possible to increase the resistance to the air flow toward the closest portion (41) in the direction opposite to the rotation direction (D), and as a result, the clearance between the closest portion (41) and the impeller (3). The high effect which suppresses the backflow which passes is obtained.

  In the cross flow fan, the intersecting direction may be a direction inclined with respect to the rotation axis (3A) of the impeller (3).

  Due to the provision of the linear protrusion (51), periodic noise (NZ sound) may occur when each of the plurality of blades (31) passes near the linear protrusion (51). is there. Therefore, in this configuration, the extending direction of the linear protrusion (51) is a direction inclined with respect to the axial direction of the rotating shaft (3A) of the impeller (3). Thereby, since the distance of a linear protrusion part (51) and each blade | wing (31) is not constant in an axial direction, it can suppress that a periodic noise arises.

  In the cross flow fan, it is preferable that the surface of the linear protrusion (51) is a convex curved surface convex toward the impeller (3).

  In this configuration, since the surface of the linear protrusion (51) is a convex curved surface, when air flows near the linear protrusion (51) in the space between the impeller (3) and the rear guider (4). The occurrence of air turbulence can be suppressed. Thereby, generation | occurrence | production of the noise resulting from turbulence of air can be suppressed.

  In the cross-flow fan, the plurality of linear protrusions (51) includes a first linear protrusion (51) and the rotation direction (D) with respect to the first linear protrusion (51). A second linear protrusion (51) adjacent to the downstream side of the second linear protrusion (51) and a third line adjacent to the downstream side of the rotational direction (D) with respect to the second linear protrusion (51). And a distance between the first linear protrusion (51) and the second linear protrusion (51) is the second linear protrusion (51). And the distance between the third linear protrusion (51) may be different.

  In this configuration, a plurality of linear protrusions (51) are provided, and the spacing between the linear protrusions (51) is non-uniform, so that the plurality of linear protrusions (51) and the plurality of blades (31) are provided. As a result, it is possible to suppress the generation of periodic noise (NZ sound).

  In the crossflow fan, the backflow suppressing means (5) may include a plurality of hairs (52) extending from the facing surface (40) toward the impeller (3).

  In this structure, since many hairs (52) are provided in the downstream of the rotation direction (D) rather than the nearest part (41), it is between an impeller (3) and a rear guider (4). In the space, it becomes resistance of the flow of air toward the closest part (41) in the reverse direction of the rotation direction (D), and as a result, the reverse flow passing through the gap between the closest part (41) and the impeller (3) also It becomes difficult to occur.

  In the cross flow fan, the backflow suppressing means (5) may include a rough surface portion (53) obtained by partially roughening the facing surface (40).

  In this configuration, since the rough surface portion (53) in which the facing surface (40) is partially roughened is provided on the downstream side in the rotation direction (D) with respect to the closest portion (41), the impeller (3 ) And the rear guider (4), it becomes resistance of the air flow toward the nearest part (41) in the direction opposite to the rotation direction (D), and as a result, the nearest part (41) and the impeller ( 3) It is difficult for reverse flow to pass through the gap with 3).

  Another cross-flow fan of the present invention has a plurality of blades (31), an impeller (3) rotating in a predetermined rotation direction (D), and a radial direction with respect to the impeller (3). A rear guider (4) having a facing surface (40) facing each other. The counter surface (40) is provided with a countercurrent suppression means (70) that suppresses the generation of a countercurrent, which is an airflow flowing in a direction opposite to the rotational direction (D) along the counter surface (40). Yes. The backflow suppressing means (70) is such that the length toward the impeller (3) in the downstream portion in the rotational direction (D) is longer than the length toward the impeller (3) in the upstream portion. It is configured to be large.

  In the present invention, the backflow suppressing means for suppressing the backflow that is the airflow flowing in the direction opposite to the rotation direction (D) along the facing surface (40) on the facing surface (40) of the rear guider (4). Since (70) is provided, it can suppress that a backflow (Fr) arises in the clearance gap between an impeller (3) and the winding start part (S) of a rear guider (4). Thereby, since the pressure fluctuation produced when a backflow (Fr) passes the clearance gap between an impeller (3) and a winding start part (S) becomes small, noise can be reduced.

  Moreover, in the present invention, the backflow suppressing means (70) is configured such that the length toward the impeller (3) side in the downstream portion in the rotation direction (D) is longer than the impeller (3) side in the upstream portion. It is comprised so that it may become larger than this. In the case where such a configuration is provided, the effect of suppressing the occurrence of surging compared to the case where the length toward the impeller (3) is the same in the upstream portion and the downstream portion. Can be increased. The reason why the surging suppression effect is increased is considered as follows. That is, in the backflow suppression means (70), the length of the downstream portion toward the impeller (3) side is made larger than the length of the upstream portion toward the impeller (3) side, for example, as will be described later. In the indoor unit of the air conditioner as shown in FIG. 14, it is possible to suppress the occurrence of a backflow (Fr ′) along the rear guider (4) in the vicinity of the outlet (13). As a result, it is possible to suppress the air volume and pressure of the air blown from the air outlet (13) from becoming unstable. This effectively suppresses surging in which noise (for example, noise called “basabasa”) generated due to instability of the air volume and pressure of air occurs.

  The following can be illustrated as a specific form which can raise a surging suppression effect. That is, in the cross flow fan, the backflow suppressing means (70) includes a plurality of linear protrusions (71) that protrude in the direction of crossing the backflow while projecting toward the impeller (3) side, Of the plurality of linear protrusions (71), the protrusion length toward the impeller (3) in the linear protrusion (71) on the most downstream side in the rotational direction (D) is different from the other linear shape. You may be comprised so that it may become larger than the protrusion length to the said impeller (3) side in a protrusion part (71).

  In this configuration, the plurality of linear protrusions (71) provided on the facing surface (40) move in the rotation direction (D) between the impeller (3) and the facing surface (40) of the rear guider (4). ) In the opposite direction to the air flow resistance toward the winding start portion (S). As a result, the backflow (Fr) that passes through the gap between the impeller (3) and the winding start portion (S) is less likely to occur.

  Moreover, in this structure, the protrusion length to the impeller (3) side in the linear protrusion (71) on the most downstream side in the rotation direction (D) is the impeller in the other linear protrusion (71). (3) It is larger than the protruding length to the side. In the case where such a configuration is provided, the surging suppression effect can be enhanced as compared with the case where the protruding lengths of the plurality of linear protruding portions (71) are the same.

  Further, as another specific form that can enhance the surging suppression effect, in the cross flow fan, the backflow suppression means (5) includes the impeller (3) in the plurality of linear protrusions (71). The protrusion length to the side may be configured to gradually increase toward the downstream side in the rotation direction (D).

  When the protrusion lengths of the plurality of linear protrusions (71) gradually increase toward the downstream side as in this configuration, surging is further increased as shown in the graph of FIG. It can be effectively suppressed.

  In the cross flow fan, in the cross section orthogonal to the rotation axis (3A) of the impeller (3), the winding start portion (S) which is the scroll shape start point on the facing surface (40) and the rotation shaft (3A) Is a first straight line (L1), and passes through a point downstream of the winding start portion (S) in the facing surface (40) in the rotation direction (D) and the rotation shaft (3A). When the straight line is the second straight line (L2), the backflow suppression means (5) is in a region where the angle (θ1) formed by the first straight line (L1) and the second straight line (L2) is 45 degrees or less. It is preferable that a part or all of is provided.

  In this configuration, in the opposed surface (40) of the rear guider (4), the backflow suppressing means (in the region where the angle (θ1) formed by the first straight line (L1) and the second straight line (L2) is 45 degrees or less ( Part or all of 5) is provided. That is, in this configuration, a part or all of the backflow suppressing means (5) is provided in a region close to the winding start portion (S), so that the gap (3) between the impeller (3) and the closest portion (41) ( It is possible to more effectively suppress the backflow (Fr) from occurring in the gap between the impeller (3) and the winding start portion (S).

  Since the indoor unit of the air conditioner of the present invention includes the cross flow fan (2), the noise of the air conditioner can be reduced.

  ADVANTAGE OF THE INVENTION According to this invention, the crossflow fan which can reduce a noise, and the indoor unit of an air conditioner provided with the same can be provided.

It is a perspective view which shows an air conditioner provided with the indoor unit which concerns on one Embodiment of this invention, and an outdoor unit. It is sectional drawing (II-II sectional view taken on the line in FIG. 1) which shows the indoor unit of an air conditioner provided with the crossflow fan which concerns on 1st Embodiment of this invention. (A) is a front view which shows the impeller and rear guider of the said cross flow fan, (B) is a front view which shows the said rear guider. It is sectional drawing to which a part of FIG. 2 was expanded. It is sectional drawing which shows the modification 1 of the crossflow fan of 1st Embodiment. It is a front view which shows the modification 2 of the crossflow fan of 1st Embodiment. It is a front view which shows the modification 3 of the crossflow fan of 1st Embodiment. (A) is sectional drawing which shows the modification 4 of the crossflow fan of 1st Embodiment, (B) is a front view which shows the rear guider in the modification 4. FIG. (A) is sectional drawing which shows the modification 5 of the crossflow fan of 1st Embodiment, (B) is a front view which shows the rear guider in the modification 5. FIG. (A) is sectional drawing which shows the modification 6 of the crossflow fan of 1st Embodiment, (B) is a front view which shows the rear guider in the modification 6, (C) is in the modification 7. It is a front view which shows a rear guider. It is a graph which shows the characteristic of the cross flow fan of a 1st embodiment shown in Drawing 3 and Drawing 4. (A), (B) is a graph which shows the characteristic of the crossflow fan of the modification 4 of 1st Embodiment shown to FIG. 8 (A), (B). It is sectional drawing which shows the crossflow fan of a reference example. It is sectional drawing which shows the flow of air when the ventilation resistance increases in the indoor unit of an air conditioner. It is sectional drawing which shows the crossflow fan of 2nd Embodiment. It is sectional drawing which shows the modification 1 of the crossflow fan of 2nd Embodiment. It is sectional drawing which shows the modification 2 of the crossflow fan of 2nd Embodiment. It is sectional drawing which shows the modification 3 of the crossflow fan of 2nd Embodiment. It is sectional drawing which shows the modification 4 of the crossflow fan of 2nd Embodiment. It is sectional drawing which shows the modification 5 of the crossflow fan of 2nd Embodiment. It is sectional drawing which shows the modification 6 of the crossflow fan of 2nd Embodiment. It is sectional drawing which shows the modification 7 of the crossflow fan of 2nd Embodiment. It is a graph which shows the relationship between the air volume in a crossflow fan, and a static pressure. (A) is sectional drawing which shows the modification of the linear protrusion in the crossflow fan of 1st Embodiment and 2nd Embodiment, (B)-(D) is an example of the shape of a linear protrusion. FIG.

  Hereinafter, a cross flow fan 2 according to an embodiment of the present invention and an indoor unit 1 of an air conditioner 9 including the same will be described with reference to the drawings.

[Overall structure of air conditioner]
FIG. 1 is a perspective view showing an air conditioner 9 according to an embodiment of the present invention. The air conditioner 9 includes an indoor unit 1 and an outdoor unit 8. In the present embodiment shown in FIG. 1, the indoor unit 1 is a wall-hanging type, but is not limited to this. The indoor unit 1 may be, for example, a floor-standing type or a ceiling-mounted type. The indoor unit 1 is connected to the outdoor unit 8 by a refrigerant pipe 14. The outdoor unit 8 includes an unillustrated evaporator, a heat exchanger, a fan, and the like. The air conditioner 9 includes an unillustrated refrigerant circuit that performs a vapor compression refrigeration cycle.

[Structure of indoor unit]
As shown in FIGS. 1 and 2, the indoor unit 1 includes a casing 10, a cross flow fan 2 housed in the casing 10, a heat exchanger 7, a drain pan 11, a filter 15, and the like. The casing 10 includes a front panel 10F, a back panel 10R, a top panel 10T, a bottom panel 10B, and the like. The casing 10 has an air inlet 12 and an air outlet 13. In the present embodiment, the suction port 12 is formed between the front panel 10F and the top panel 10T, and the air outlet 13 is formed between the front panel 10F and the bottom panel 10B. Not limited to. The air outlet 13 is provided with a flap 16 for adjusting the air blowing direction into the room.

  The heat exchanger 7 includes a front heat exchanger 7A provided on the front panel 10F side in the casing 10 and a rear heat exchanger 7B provided on the back panel 10R side. These heat exchangers 7A and 7B are arranged in an inverted V shape. For example, a fin-and-tube type heat exchanger can be used as the heat exchanger 7, but the heat exchanger 7 is not limited thereto.

  The drain pan 11 includes a front drain pan 11A disposed along the lower end portion of the front heat exchanger 7A, and a rear drain pan 11B disposed along the lower end portion of the rear heat exchanger 7B.

  The cross flow fan 2 is arranged on the back side of the front heat exchanger 7A and below the rear heat exchanger 7B. The cross flow fan 2 forms an airflow F in the casing 10 that flows in the order of the suction port 12, the heat exchanger 7, and the air outlet 13 as indicated by arrows in FIG. 2. The cross flow fan 2 includes an impeller 3 (fan rotor 3), a rear guider 4 (back scroll 4), and a stabilizer 6 (tongue 6).

  The filter 15 is disposed along the heat exchanger 7 between the suction port 12 and the heat exchanger 7. The filter 15 removes dust and the like sucked into the casing 10 together with air through the suction port 12.

  As shown in FIGS. 2 and 3A, the impeller 3 has a substantially cylindrical shape extending along the longitudinal direction of the casing 10 (horizontal direction in the present embodiment). The impeller 3 includes a plurality of blades 31, one or more partitions 32, and a pair of end plates 33, 33 provided at both ends in the axial direction. One end plate 33 of the impeller 3 has a shaft portion 35 disposed on the rotation shaft 3A. The shaft portion 35 is supported by the casing 10, for example. A motor 34 is disposed on the other end plate 33 side. The impeller 3 is rotated by a motor 34. In this embodiment, although the impeller 3 is arrange | positioned in the downstream of the direction where air flows with respect to the heat exchanger 7, it is not limited to this, It is arrange | positioned upstream from the heat exchanger 7. Also good.

  As shown in FIG. 1, the plurality of blades 31 are arranged along the circumferential direction around the rotation shaft 3 </ b> A of the impeller 3. Adjacent blades 31 are arranged at a predetermined interval. Each blade 31 is a forward blade that curves in the rotational direction D as it goes radially outward. Each blade 31 has a pressure surface and a suction surface. The pressure surface is the surface of the impeller 3 on the rotational direction D side, and the negative pressure surface is the surface of the impeller 3 opposite to the rotational direction D. The negative pressure surface is a convex curved surface that is convex on the opposite side of the rotation direction D. The pressure surface is a concave curved surface that is recessed on the opposite side of the rotation direction D.

  As shown in FIG. 2, the rear guider 4 has a facing surface 40 that faces the impeller 3 in the radial direction. The facing surface 40 functions as a guide surface that guides the airflow F formed by the impeller 3 to the air outlet 13. The facing surface 40 is a concave curved surface that is located on the radially outer side of the impeller 3 and is recessed on the radially outer side. The facing surface 40 is provided with a gap between it and the impeller 3.

  The facing surface 40 has a winding start portion S that is a scroll-shaped starting point at one end thereof or in the vicinity thereof (in the present embodiment, at the upper end or in the vicinity thereof). The winding start portion S is one end of the concave curved surface (the upper end of the concave curved surface in FIG. 2) that constitutes the scroll-shaped facing surface 40 that is smoothly continuous. The rear guider 4 has a closest portion 41 that is closest to the impeller 3 at or near the winding start portion S. On the downstream side of the closest part 41 (on the outlet 13 side), the distance between the facing surface 40 and the impeller 3 is gradually increased. As shown in FIG. 3A, the facing surface 40 has the same length as the impeller 3 in the axial direction of the rotation shaft 3 </ b> A of the impeller 3. That is, the facing surface 40 is provided in a region that covers the impeller 3 from the back side.

  In the present embodiment, the rear guider 4 is formed integrally with the rear drain pan 11B. However, the rear guider 4 is not limited to this, and may be a separate body from the rear drain pan 11B. A rear drain pan 11B is formed above the winding start portion S at the upper end of the rear guider 4. The rear drain pan 11B has a wall (front wall) 11F extending obliquely upward from the winding start portion S of the rear guider 4.

  The stabilizer 6 is disposed on the radially outer side of the impeller 3 with a gap between the stabilizer 6 and the impeller 3. The stabilizer 6 has a surface 61 close to the impeller 3 on the side opposite to the rear guider 4 (in the present embodiment, the front panel 10F side) with respect to the impeller 3. In the present embodiment, the stabilizer 6 is formed integrally with the front drain pan 11A, but is not limited thereto, and may be separate from the front drain pan 11A.

  When the impeller 3 is rotated in the rotation direction D of the solid arrow shown in FIG. 2 by the motor 34, the indoor air is sucked into the casing 10 through the suction port 12 provided in the casing 10 as indicated by the arrow F. The sucked air undergoes heat exchange with the refrigerant when passing through the heat exchanger 7, and the temperature is adjusted. The temperature-adjusted air passes through the impeller 3 and is blown out into the room from an air outlet 13 provided in the casing 10. In addition, as shown in FIG. 4, the vortex | eddy_current F1 may arise in the clearance gap between the impeller 3 and the front wall 11F of the rear side drain pan 11B.

[Backflow suppression means: first embodiment]
Next, the backflow suppression means 5 provided in the cross flow fan 2 of this embodiment will be described. As shown in FIG. 13, in the cross flow fan 102 of the reference example, in the gap between the impeller 3 and the closest portion 41, a backflow Fr that is a flow of air that flows in the direction opposite to the rotation direction D is likely to occur. Such a back flow causes noise.

  The backflow suppressing means 5 provided in the cross flow fan 2 of the present embodiment has a function of suppressing the backflow Fr from being generated in the gap between the impeller 3 and the closest portion 41. The backflow suppressing means 5 is provided downstream of the closest portion 41 in the rotational direction D, and the air flowing toward the closest portion 41 in the reverse direction of the rotational direction D in the space between the impeller 3 and the rear guider 4 is provided. Makes the flow difficult. As a result, in this embodiment, the backflow Fr passing through the gap between the closest portion 41 and the impeller 3 is less likely to occur than in the reference example shown in FIG.

  In the present embodiment shown in FIGS. 3A, 3B, and 4, the backflow suppressing means 5 is constituted by a plurality of linear protrusions 51, 51 (a plurality of ribs 51, 51). The opposing surface 40 is provided with three linear protrusions 51A, 51, 51, and the backflow suppressing means 5 is the uppermost linear protrusion 51A among the three linear protrusions 51A, 51, 51. It is comprised by the two linear protrusion parts 51 and 51 except for. Specifically, it is as follows.

  If the three linear protrusions 51A, 51, 51 are not provided in FIG. 4, the closest portion 41 closest to the impeller 3 becomes the winding start portion S, but this embodiment shown in FIG. In the embodiment, the linear protrusion 51A is provided in the vicinity of the winding start portion S (immediately below the winding start portion S), and the protrusion length of the linear protrusion 51A is relatively large. The linear protrusion 51A is the closest portion 41. Therefore, in this embodiment shown in FIG. 4, the backflow suppressing means 5 includes two linear protrusions 51, 51 excluding the uppermost linear protrusion 51A among the three linear protrusions 51A, 51, 51. It is constituted by.

  The two linear protrusions 51, 51 are provided on the downstream side in the rotation direction D with respect to the closest part 41 (the uppermost linear protrusion 51 </ b> A), and the impeller 3 and the opposing surface 40 of the rear guider 4 In the space between them, the flow of air toward the closest portion 41 (the uppermost linear protrusion 51A) in the direction opposite to the rotation direction D is made difficult to occur. As a result, backflow that passes through the gap between the closest portion 41 (the uppermost linear protrusion 51A) and the impeller 3 is also less likely to occur.

  The linear protrusion 51A (uppermost linear protrusion 51A) closest to the winding start portion S has a function of reducing the distance between the closest portion 41 and the impeller 3. Since the reverse flow is less likely to pass between the closest portion 41 and the impeller 3, the reverse flow is further less likely to occur.

  As shown in FIGS. 3B and 4, in the present embodiment, the linear protrusions 51A, 51, 51 have substantially the same shape, but are not limited to this, and have different shapes. It may be. Each of these linear protrusions 51A, 51, 51 is a linear protrusion that protrudes toward the impeller 3 and extends linearly in a direction intersecting with the backflow (direction intersecting the rotational direction D). In the present embodiment, the intersecting direction is a direction parallel to the rotation shaft 3 </ b> A of the impeller 3. In other words, each of the linear protrusions 51 </ b> A, 51, 51 extends in a direction parallel to the rotation shaft 3 </ b> A of the impeller 3. As shown in FIG. 3A, each of the linear protrusions 51 </ b> A, 51, 51 has a length approximately the same as the length of the impeller 3. In the present embodiment, each of the linear protrusions 51A, 51, 51 is continuous from one end to the other end in the length direction. However, the present invention is not limited to this, and a plurality of pieces divided into a plurality in the length direction. It may be constituted by divided parts. In this case, the length of each of the plurality of divided portions is preferably larger than the gap between the divided portions adjacent in the length direction.

  Moreover, in this embodiment, linear protrusion part 51A, 51, 51 is arrange | positioned at intervals. The linear protrusions 51A, 51, 51 are arranged at substantially equal intervals, but are not limited to this, and may not be equally spaced, for example, as in a modification described later. In the present embodiment, each of the linear protrusions 51A, 51, 51 has the same protrusion length toward the impeller 3 side, but is not limited thereto, and the protrusion lengths may be different from each other. .

  As shown in FIG. 4, each surface of the linear protrusions 51A, 51, 51 is a convex curved surface that is convex toward the impeller 3 side. Specifically, each of the linear protrusions 51A, 51, 51 has a shape obtained by cutting a cylinder along a plane parallel to the axial direction, but is not limited thereto. Specifically, in this embodiment, each surface of the linear protrusions 51A, 51, 51 has an arc shape in the cross section shown in FIG. 4 (the cross section orthogonal to the rotation shaft 3A of the impeller 3). However, it is not limited to this. Each surface of the linear protrusions 51A, 51, 51 may not necessarily be a convex curved surface.

  The region where the backflow suppressing means 5 is provided on the facing surface 40 is not particularly limited, but it is possible to prevent the backflow from occurring in the gap between the impeller 3 and the closest portion 41. It is good to be provided in the vicinity (near the winding start part S).

  For example, in a cross section orthogonal to the rotation axis 3A of the impeller 3 as shown in FIG. 4, a straight line passing through the winding start portion S and the rotation shaft 3A on the facing surface 40 is defined as a first straight line L1, and the winding start portion on the facing surface 40 A straight line passing through a point downstream of S in the rotation direction D and the rotation shaft 3A is defined as a second straight line L2. At this time, it is preferable that a part or all of the backflow suppression means 5 is provided in a region where the angle between the first straight line L1 and the second straight line L2 is θ1. The angle θ1 formed by the straight line L1 and the straight line L2 is preferably 45 degrees or less, more preferably 30 degrees or less, and even more preferably 15 degrees or less. This preferable range is the same also in the modification of 1st Embodiment mentioned later, 2nd Embodiment, and its modification.

  In the specific example shown in FIG. 4, all of the plurality of linear protrusions 51 as the backflow suppressing means 5 are provided within the range of the angle θ1. In this case, the second straight line L2 is a straight line that passes through the downstream end (the downstream end in the rotation direction D) of the region where the backflow suppressing means 5 is provided and the rotation shaft 3A. Note that some of the plurality of linear protrusions 51 may be provided outside the region of the angle θ1.

[First Modification of First Embodiment]
FIG. 5 is a cross-sectional view illustrating Modification 1 of the cross flow fan 2 of the embodiment. In the embodiment shown in FIG. 4, the linear protrusion 51A closest to the winding start portion S among the plurality of linear protrusions 51A, 51, 51 is the closest portion 41, and the other linear shapes The protrusions 51 and 52 constitute the backflow suppressing means 5. The modification 1 shown in FIG. 5 is different from the embodiment shown in FIG. 4 in that all of the plurality of linear protrusions 51, 51, 51 constitute the backflow suppressing means 5. This is the same as the embodiment shown in FIG.

  In the first modification shown in FIG. 5, the closest portion 41 that is the closest to the impeller 3 is the winding start portion S, and each of the plurality of linear projecting portions 51, 51, 51 and the impeller 3 The distance is larger than the distance between the winding start portion S and the impeller 3. An arc R indicated by a one-dot chain line in FIG. 5 is an arc passing through the winding start portion S with the rotation shaft 3 </ b> A of the impeller 3 as the center. As shown in FIG. 5, the plurality of linear protrusions 51, 51, 51 are located on the radially outer side than the arc R.

  Also in the modification 1, the backflow suppression means 5 has a function of suppressing the backflow Fr from being generated in the gap between the impeller 3 and the closest portion 41 (winding start portion S) as in the above embodiment. The backflow suppressing means 5 is provided downstream of the closest portion 41 (winding start portion S) in the rotation direction D, and is located in a direction opposite to the rotation direction D in the space between the impeller 3 and the rear guider 4. It is made difficult to produce the flow of the air which goes to the contact part 41 (winding start part S).

[Modification 2 of the first embodiment]
Drawing 6 is a front view showing modification 2 of cross flow fan 2 of an embodiment. This modification 2 is different from the embodiment shown in FIG. 4 in that the spacing between the linear protrusions is not uniform, and the other configuration is the same as that of the embodiment shown in FIG.

  As shown in FIG. 6, among the plurality of linear protrusions 51 </ b> A, 51, 51, 51, the linear protrusion 51 </ b> A closest to the winding start part S is the closest part 41, and the other linear protrusions 51, 51, 51 constitutes the backflow suppressing means 5. That is, the backflow suppressing means 5 includes the first linear protrusion 511 (51) and the second linear protrusion adjacent to the first linear protrusion 511 (51) on the downstream side in the rotation direction D. The protrusion part 512 (51) and the 3rd linear protrusion part 513 (51) adjacent to the downstream of the rotation direction D with respect to the 2nd linear protrusion part 512 (51) are included.

  The distance D2 between the first linear protrusion 511 and the second linear protrusion 512 is different from the distance D3 between the second linear protrusion 512 and the third linear protrusion 513. In the second modification shown in FIG. 6, the interval D3 is larger than the interval D2. That is, in the linear protrusions 51, 51, 51 constituting the backflow suppressing means 5, the interval is increased toward the downstream side, but is not limited thereto. For example, the interval may be smaller toward the downstream side, or may be random.

  In the second modification, the interval D1 between the linear protrusion 51A closest to the winding start portion S and the first linear protrusion 511 is different from the interval D2 and the interval D3. The interval D2 is larger than the interval D1. In the plurality of linear protrusions 51A, 51, 51, 51, the interval is increased toward the downstream side, but the present invention is not limited to this. For example, the interval may be smaller toward the downstream side, or may be random.

  As described above, in the second modification, the intervals between the linear protrusions are non-uniform, so that the periodicity of the positional relationship between the plurality of linear protrusions 51A, 51, 51, 51 and the plurality of blades 31 is lost. As a result, generation of periodic noise (NZ sound) can be suppressed.

[Modification 3 of the first embodiment]
FIG. 7 is a front view showing Modification 3 of the crossflow fan 2 of the embodiment. This modification 3 is different from the embodiment shown in FIG. 4 in that the extending direction of the linear protrusion 51 is a direction inclined with respect to the rotating shaft 3A, and other configurations are shown in FIG. This is the same as the embodiment.

  As shown in FIG. 7, each of the plurality of linear protrusions 51 </ b> A, 51, 51 extends in a direction inclined with respect to the rotation shaft 3 </ b> A of the impeller 3. A straight line L3 indicated by a one-dot chain line in FIG. 7 is a straight line parallel to the rotation shaft 3A of the impeller 3. The linear protrusion 51 is inclined by an angle θ2 with respect to the straight line L3. In the third modification shown in FIG. 7, the inclination angles of the plurality of linear protrusions 51A, 51, 51 are the same, but they may be different from each other.

  In the modified example 3, since the extending direction of the linear protrusion 51 is a direction inclined with respect to the rotation shaft 3A of the impeller 3, the distance between the linear protrusion 51 and each blade 31 is the axis of the rotation shaft 3A. It is no longer constant in direction. As a result, since the periodicity when each of the plurality of blades 31 passes in the vicinity of the linear protrusion 51 is broken, generation of periodic noise can be suppressed.

[Modification 4 of the first embodiment]
FIG. 8A is a cross-sectional view showing a fourth modification of the cross flow fan 2 of the embodiment, and FIG. 8B is a front view showing the rear guider 4 in the fourth modification. The modification 4 differs in the structure of the backflow suppression means 5 from the embodiment shown in FIG. 4, and the other structure is the same as that of the embodiment shown in FIG.

  As shown in FIGS. 8A and 8B, in Modification 4, the backflow suppressing means 5 is configured by a large number of hairs 52 extending from the facing surface 40 toward the impeller 3 side. Each hairy body 52 can be exemplified by soft hair and bristles. The soft hair is formed of, for example, a soft resin. The bristles are formed of, for example, hard resin or metal. A large number of the hair bodies 52 are preferably provided, for example, in a region between the straight line L1 and the straight line L2 shown in FIG. As shown in FIG. 8B, the many hair bodies 52 are arranged in the direction of the rotating shaft 3A and in the direction orthogonal thereto.

  Also in the modified example 4, as in the above-described embodiment, the backflow suppressing means 5 has a function of suppressing the backflow Fr from occurring in the gap between the impeller 3 and the closest portion 41 (winding start portion S). The backflow suppressing means 5 is provided downstream of the closest portion 41 (winding start portion S) in the rotational direction D, and is closest to the reverse direction of the rotational direction D in the space between the impeller 3 and the rear guider 4. The flow of the air which goes to the part 41 (winding start part S) is made hard to produce.

[Modification 5 of the first embodiment]
FIG. 9A is a cross-sectional view showing a fifth modification of the crossflow fan 2 of the embodiment, and FIG. 9B is a front view showing the rear guider 4 in the fifth modification. The modified example 5 is different from the embodiment shown in FIG. 4 in the configuration of the backflow suppressing means 5, and other configurations are the same as those in the embodiment shown in FIG. 4.

  As shown in FIGS. 9A and 9B, in Modification 5, the backflow suppressing means 5 is constituted by a rough surface portion 53 in which the facing surface 40 is partially roughened. The rough surface portion 53 is a surface having a greater degree of unevenness than the surrounding surface. The rough surface portion 53 is preferably provided, for example, in a region between the straight line L1 and the straight line L2 shown in FIG.

  Also in the modified example 5, as in the above-described embodiment, the backflow suppressing means 5 has a function of suppressing the backflow Fr from occurring in the gap between the impeller 3 and the closest portion 41 (winding start portion S). The backflow suppressing means 5 is provided downstream of the closest portion 41 (winding start portion S) in the rotational direction D, and is closest to the reverse direction of the rotational direction D in the space between the impeller 3 and the rear guider 4. The flow of the air which goes to the part 41 (winding start part S) is made hard to produce.

[Modification 6 of the first embodiment]
FIG. 10A is a cross-sectional view showing a sixth modification of the crossflow fan 2 of the embodiment, and FIG. 10B is a front view showing the rear guider 4 in the sixth modification. Modification 6 is different from the embodiment shown in FIG. 4 in the configuration of the backflow suppressing means 5, and other configurations are the same as those in the embodiment shown in FIG. 4.

  As shown in FIGS. 10A and 10B, in the sixth modification, the backflow suppressing means 5 is configured by a large number of protrusions 54 provided on the facing surface 40. The many protrusions 54 are preferably provided, for example, in a region between the straight line L1 and the straight line L2 shown in FIG. As shown in FIG. 10B, the multiple protrusions 54 are arranged in the direction of the rotation shaft 3A and in the direction orthogonal thereto. A large number of the protrusions 54 are spaced apart from each other. As shown in FIG. 10A, each protrusion 54 protrudes toward the impeller 3 side. In the modified example 6 shown in FIGS. 10A and 10B, each protrusion 54 has a hemispherical shape, but is not limited thereto.

  As shown in FIGS. 10A and 10B, the multiple protrusions 54 are arranged in a plurality of rows. As shown in FIG. 10B, in each row, the plurality of protrusions 54 are arranged in a direction intersecting with the rotation direction D (specifically, a direction orthogonal to the rotation direction D, that is, a direction parallel to the rotation axis A). Yes. A plurality of rows (three rows in FIGS. 10A and 10B) are arranged in the rotation direction D.

  Also in the modified example 6, as in the above-described embodiment, the backflow suppressing unit 5 has a function of suppressing the backflow Fr from being generated in the gap between the impeller 3 and the closest portion 41 (winding start portion S). The backflow suppressing means 5 is provided downstream of the closest portion 41 (winding start portion S) in the rotational direction D, and is closest to the reverse direction of the rotational direction D in the space between the impeller 3 and the rear guider 4. The flow of the air which goes to the part 41 (winding start part S) is made hard to produce.

[Modification 7 of First Embodiment]
FIG. 10C is a front view showing the rear guider 4 in Modification 7. FIG. This modified example 7 is the same as the modified example 6 shown in FIGS. 10A and 10B in that the backflow suppressing means 5 is constituted by a large number of projections 54 provided on the opposing surface 40. The arrangement of 54 is different from that of the sixth modification.

  In the modified example 7 shown in FIG. 10C, the many protrusions 54 are arranged in a plurality of rows. In each row, the plurality of protrusions 54 are arranged in a direction intersecting with the rotation direction D (specifically, a direction orthogonal to the rotation direction D, that is, a direction parallel to the rotation axis A). A plurality of rows (three rows in FIG. 10C) are arranged in the rotation direction D. When adjacent rows are compared, the plurality of protrusions 54 constituting one row and the plurality of protrusions 54 constituting the other row rotate in the direction in which the rows extend (that is, in FIG. 10C). (Direction perpendicular to the direction D). Thereby, in the modified example 7, when the backflow suppressing means 5 is viewed in the rotation direction D, the gap between the protrusions 54 can be made smaller than that of the modified example 6 (or the gap between the protrusions 54 is eliminated). Therefore, in the modified example 7, the resistance of the air flow toward the closest portion 41 in the direction opposite to the rotation direction D in the space between the impeller 3 and the rear guider 4 can be increased compared to the modified example 6. , The backflow Fr can be further suppressed.

  Specifically, in FIG. 10C, of the three rows, the second row adjacent to the first row closest to the winding start portion S is the pitch between the protrusions 54 in the first row. It is shifted in the direction in which the row extends by half the length. The third row adjacent to the second row is shifted in the direction in which the row extends by a length that is half the pitch between the protrusions 54 in the second row. The plurality of protrusions 54 constituting the first row and the plurality of protrusions 54 constituting the third row are not displaced in the direction in which the rows extend.

[Evaluation results]
FIG. 11 is a graph comparing the characteristics of the cross flow fan 2 of the embodiment shown in FIGS. 3 and 4 with the characteristics of the cross flow fan 102 of the reference example shown in FIG. As shown in FIG. 11, in the cross flow fan 2 according to the embodiment in which the backflow suppressing means 5 is provided on the facing surface 40, the blowing sound at the same air volume is reduced by about 0.3 dBA compared to the reference example. I understand that. In FIG. 11, the scale on the horizontal axis is 0.5 m ³ / min indicated by the arrow in FIG. 11, and the scale on the vertical axis is 1 dBA indicated by the arrow in FIG.

12A and 12B are graphs comparing the characteristics of the cross flow fan 2 shown in FIGS. 8A and 8B with the characteristics of the cross flow fan 102 of the reference example shown in FIG. It is. As shown in FIG. 12A, the cross flow fan 2 according to the embodiment in which the backflow suppressing means 5 is provided on the facing surface 40 has a motor input of about 0.7 W when the air flow is the same as in the reference example. Further, as shown in FIG. 12B, it can be seen that the blowing sound at the same air volume is reduced by about 0.2 dBA as compared with the reference example. 12A and 12B, the scale on the horizontal axis is 0.5 m ³ / min as shown by the arrows in FIGS. 12A and 12B. Further, the scale of the vertical axis is 5 W indicated by an arrow in FIG. 12A and 1 dBA indicated by an arrow in FIG.

[Summary of First Embodiment]
In the cross flow fan 2 according to the embodiment and each modified example, the backflow suppressing means 5 is provided on the opposed surface 40 of the rear guider 4 on the downstream side in the rotational direction D with respect to the closest portion 41. Backflow can be prevented from occurring in the gap with the contact portion 41. That is, in this embodiment, the backflow suppression means 5 provided downstream of the closest portion 41 in the rotational direction D is closest to the reverse direction of the rotational direction D in the space between the impeller 3 and the rear guider 4. The flow of air toward the portion 41 is less likely to occur, and as a result, the backflow that passes through the gap between the closest portion 41 and the impeller 3 is also less likely to occur. Therefore, since the pressure fluctuation generated when the reverse flow passes through the gap between the closest portion 41 and the impeller 3 can be reduced, noise can be reduced.

  In the crossflow fan 2 of the embodiment and the modified example 1-3, the backflow suppressing means 5 includes one or a plurality of linear protrusions 51 that protrude toward the impeller 3 and extend linearly in a direction intersecting with the backflow. Contains. In this configuration, a linear protrusion 51 is provided on the downstream side in the rotation direction D from the closest portion 41, and the linear protrusion 51 protrudes toward the impeller 3 and linearly intersects with the backflow. Since it extends, it becomes resistance of the flow of the air which goes to the nearest part 41 in the reverse direction of the rotation direction D in the space between the impeller 3 and the rear guider 4, and as a result, the nearest part 41 and the impeller 3 Back flow that passes through the gap is less likely to occur.

  In the cross flow fan 2 of the embodiment and the first and second modifications, the intersecting direction is a direction parallel to the axial direction of the rotating shaft 3 </ b> A of the impeller 3. In this configuration, in the space between the impeller 3 and the rear guider 4, the extending direction of the linear protrusion 51 is approximately orthogonal to the air flow toward the closest portion 41 in the reverse direction of the rotation direction D. Become. Therefore, the resistance to the air flow toward the closest portion 41 in the reverse direction of the rotation direction D can be increased, and as a result, the backflow that passes through the gap between the closest portion 41 and the impeller 3 is less likely to occur. .

  In the cross flow fan 2 of Modification 3, the intersecting direction is a direction inclined with respect to the axial direction of the rotating shaft 3 </ b> A of the impeller 3. The gap between the linear protrusion 51 and the impeller 3 is larger than the gap between the closest portion 41 and the impeller 3. Therefore, noise caused by air flowing in the gap between the linear protrusion 51 and the impeller 3 in the direction opposite to the rotation direction D causes the gap between the closest portion 41 and the impeller 3 to be opposite to the rotation direction D. Compared to noise caused by air flow. However, periodic noise (NZ sound) due to each of the plurality of blades 31 passing near the linear protrusion 51 may occur. In this configuration, since the extending direction of the linear protrusion 51 is a direction inclined with respect to the axial direction of the rotating shaft 3A of the impeller 3, the distance between the linear protrusion 51 and each blade 31 is set in the axial direction. It will not be constant. As a result, since the periodicity when each of the plurality of blades 31 passes in the vicinity of the linear protrusion 51 is broken, generation of periodic noise can be suppressed.

  In the cross flow fan 2 of the embodiment and the modification 1-3, the surface of the linear protrusion 51 is a convex curved surface that is convex toward the impeller 3 side. In this configuration, since the surface of the linear protrusion 51 is a convex curved surface, air turbulence occurs when air flows in the vicinity of the linear protrusion 51 in the space between the impeller 3 and the rear guider 4. Can be suppressed. Thereby, generation | occurrence | production of the noise resulting from turbulence of air can be suppressed.

  In the cross flow fan 2 of Modification 2, the plurality of linear protrusions 51 are adjacent to the first linear protrusions 51 and the first linear protrusions 51 on the downstream side in the rotation direction D. A first linear protrusion including a second linear protrusion 51 and a third linear protrusion 51 adjacent to the second linear protrusion 51 on the downstream side in the rotation direction D. The interval between the portion 51 and the second linear protrusion 51 is different from the interval between the second linear protrusion 51 and the third linear protrusion 51. In this configuration, a plurality of linear protrusions 51 are provided, and the intervals between the linear protrusions 51 are non-uniform, so that the periodicity of the positional relationship between the plurality of linear protrusions 51 and the plurality of blades 31 is improved. As a result, it is possible to suppress the generation of periodic noise (NZ sound).

  In the crossflow fan of the modification 4, the backflow suppressing means 5 includes a large number of hairs 52 extending from the facing surface 40 toward the impeller 3 side. In this configuration, since many hairs 52 are provided on the downstream side in the rotation direction D from the closest portion 41, the space between the impeller 3 and the rear guider 4 is the latest in the direction opposite to the rotation direction D. It becomes resistance of the flow of the air which goes to the contact part 41, As a result, it becomes difficult to produce the backflow which passes through the clearance gap between the closest part 41 and the impeller 3. FIG.

  In the cross flow fan 2 of the modified example 5, the backflow suppressing means 5 includes a rough surface portion 53 in which the facing surface 40 is partially roughened. In this configuration, a rough surface portion 53 is provided in which the facing surface 40 is partially roughened on the downstream side in the rotation direction D with respect to the closest portion 41, so in the space between the impeller 3 and the rear guider 4. It becomes resistance of the flow of the air which goes to the nearest part 41 in the reverse direction of the rotation direction D, As a result, it becomes difficult to produce the reverse flow which passes through the clearance gap between the nearest part 41 and the impeller 3.

[Backflow suppression means: second embodiment]
FIG. 14 shows the air flow when the ventilation resistance is increased in the indoor unit 1 of the air conditioner 9. In the indoor unit 1, the ventilation resistance may increase due to, for example, clogging of the filter 15 or the direction of the flap 16 at the air outlet 13. In the state of high static pressure and low air volume with increased ventilation resistance, the backflow Fr ′ along the facing surface 40 of the rear guider 4 is likely to occur near the outlet 13. When such a backflow Fr ′ is generated, the air volume and pressure of the air blown out from the outlet 13 become unstable. Surging may occur when the air volume or pressure of air becomes unstable. Surging is a phenomenon in which noise such as “bazabasa” is generated due to unstable air volume and pressure of air.

  The cross flow fan 2 according to the second embodiment of the present invention suppresses the occurrence of the backflow Fr (see FIG. 4) in the gap between the impeller 3 and the winding start portion S, as in the first embodiment. it can. Moreover, the cross flow fan 2 of the second embodiment can also effectively suppress the backflow Fr ′ in the vicinity of the air outlet 13 as shown in FIG. By suppressing the backflow Fr ′ in the vicinity of the air outlet 13, it is possible to suppress the occurrence of surging.

  Examples of the cross flow fan 2 according to the second embodiment include forms shown in FIGS. 15 to 22 described below, but are not limited thereto. In the second embodiment shown in FIGS. 15 to 22, the backflow suppressing means 70 has a length to the impeller 3 side in the downstream portion in the rotation direction D from a length to the impeller 3 side in the upstream portion. Is configured to be larger. Hereinafter, the second embodiment will be specifically described with reference to FIGS. 15 to 22.

  FIG. 15 is a cross-sectional view showing the crossflow fan 2 of the second embodiment. In the cross flow fan 2 shown in FIG. 15, the backflow suppression means 70 protrudes toward the impeller 3 and extends linearly in a direction intersecting with the backflow Fr (in the illustrated example, three linear protrusions 71). Part 71). Among the plurality of linear protrusions 71, the protrusion length of the linear protrusion 71 on the most downstream side in the rotation direction D toward the impeller 3 is the blade in the linear protrusion 71 on the upstream side of this. It is larger than the protruding length toward the car 3 side. In the form shown in FIG. 15, the protruding lengths of the two linear protruding portions 71 on the upstream side are the same, but are not limited thereto, and may be different.

  Each linear protrusion 71 is formed to protrude toward the impeller 3 from a curved surface 40S (reference surface 40S) extending from the winding start portion S along the rotational direction D while smoothly curving downstream. The protrusion length of each linear protrusion 71 is the height (maximum length) from the reference surface 40S to the rotating shaft 3A side of the impeller 3 (a modification of the second embodiment shown in FIGS. 16 to 20). The same applies to 1 to 6).

  The reference surface 40S is, for example, a spiral curved surface defined from the winding start portion S with a predetermined magnification. Examples of the reference plane 40S defined by such a predetermined magnification include, but are not limited to, a reference plane based on the Archimedes spiral and a reference plane based on a logarithmic spiral.

  In the form shown in FIG. 15, the closest portion 41 having the closest distance to the impeller 3 on the facing surface 40 is not the winding start portion S but the linear protrusion 71 on the most downstream side. In FIG. 15, an alternate long and short dash line arc R is an arc R that touches the linear protrusion 71 on the most downstream side with the rotation shaft 3 </ b> A of the impeller 3 as the center. However, in the second embodiment, the closest portion 41 does not have to be the linear protrusion 71 on the most downstream side, for example, as shown in Modification 2 shown in FIG. 17 and Modification 3 shown in FIG. The winding start portion S may be used.

  Also in the second embodiment shown in FIG. 15, each of the plurality of linear protrusions 71 intersects with the backflow Fr (for example, on the rotation axis A) like the plurality of linear protrusions 51 shown in FIG. (Parallel direction) extends linearly (the same applies to Modifications 1 to 6 of the second embodiment shown in FIGS. 16 to 20).

  Also in the second embodiment, each of the plurality of linear protrusions 71 is relative to the rotating shaft 3A of the impeller 3 like the linear protrusion 51 in Modification 3 of the first embodiment shown in FIG. And may extend in an inclined direction (the same applies to Modifications 1 to 6 of the second embodiment shown in FIGS. 16 to 20).

  Moreover, in the modification 2 of 1st Embodiment shown in FIG. 6, the space | interval of the 1st linear protrusion part 51 and the 2nd linear protrusion part 51 is the 2nd linear protrusion part 51 and the 3rd linear form. In the second embodiment shown in FIG. 15, the plurality of linear protrusions 71 may have a structure similar to the structure shown in FIG. The same applies to Modifications 1 to 6 of the second embodiment shown in FIG.

[Modification 1 of the second embodiment]
FIG. 16 is a cross-sectional view showing Modification 1 of the crossflow fan 2 of the second embodiment. In the modification 1 of 2nd Embodiment shown in FIG. 16, the protrusion length to the impeller 3 side in the some linear protrusion part 71 becomes large gradually as it goes to the downstream of the rotation direction D. As shown in FIG.

  In the first modification of the second embodiment shown in FIG. 16, the closest portion 41 having the closest distance to the impeller 3 on the facing surface 40 is not the winding start portion S but the linear protrusion 71 on the most downstream side. It is. In FIG. 16, the dashed-dotted arc is an arc R in contact with the linear protrusion 71 on the most downstream side. The linear protrusion 71 on the upstream side of the linear protrusion 71 on the most downstream side is located on the radially outer side of the arc R.

[Modification 2 and Modification 3 of Second Embodiment]
FIG. 17 is a cross-sectional view showing a second modification of the crossflow fan 2 of the second embodiment, and FIG. 18 is a cross-sectional view showing a third modification of the crossflow fan of the second embodiment.

  In Modification 2 and Modification 3 of the second embodiment shown in FIGS. 17 and 18, the closest portion 41 closest to the impeller 3 on the facing surface 40 is the winding start portion S, and a plurality of linear protrusions The distance between each of 71 and the impeller 3 is greater than the distance between the winding start portion S and the impeller 3. An arc R indicated by a one-dot chain line in FIGS. 17 and 18 is an arc passing through the winding start portion S with the rotation shaft 3 </ b> A of the impeller 3 as the center. As shown in FIG. 17, the plurality of linear protrusions 71, 71, 71 are located on the radially outer side than the arc R.

  In the modification 2 of 2nd Embodiment shown in FIG. 17, the protrusion length to the impeller 3 side in the linear protrusion part 71 located in the most downstream side of the rotation direction D among the several linear protrusion parts 71 is the following. It is larger than the protrusion length to the impeller 3 side in the linear protrusion 71 on the upstream side. In the form shown in FIG. 17, the protruding lengths of the two linear protruding portions 71 on the upstream side are the same, but are not limited to this, and may be different. In the modification 3 of 2nd Embodiment shown in FIG. 18, the protrusion length to the impeller 3 side in the some linear protrusion part 71 becomes large gradually as it goes to the downstream of the rotation direction D. As shown in FIG.

[Modification 4 and Modification 5 of Second Embodiment]
FIG. 19 is a cross-sectional view showing Modification 4 of the crossflow fan of the second embodiment, and FIG. 20 is a cross-sectional view showing Modification 5 of the crossflow fan of the second embodiment. In these modified examples 4 and 5, the projecting length of the plurality of linear projecting parts 71 toward the impeller 3 side gradually increases toward the downstream side in the rotation direction D.

  19 and 20, the arc R indicated by the alternate long and short dash line is an arc that touches the plurality of linear protrusions 71 around the rotation shaft 3 </ b> A of the impeller 3, and the arc 3 indicated by the two-dot chain line indicates the impeller 3. Is a part of the circumscribed circle that circumscribes As shown in FIGS. 19 and 20, in the fourth modification and the fifth modification of the second embodiment, the distances between the plurality of linear protrusions 71 and the impeller 3 are the same.

  In the fourth modification of the second embodiment shown in FIG. 19, the closest portion 41 closest to the impeller 3 on the facing surface 40 is a plurality of linear protrusions 71. That is, in the fourth modification, the distance between the winding start portion S and the impeller 3 is larger than the distance between the linear protrusion 71 and the impeller 3. The winding start portion S is located on the outer side in the radial direction than the arc R.

  In the fifth modification of the second embodiment shown in FIG. 20, the winding start portion S is provided at a position in contact with the arc R. That is, in this modified example 5, the closest portion 41 closest to the impeller 3 on the facing surface 40 is the winding start portion S and the plurality of linear protrusions 71. The distance between the winding start portion S and the impeller 3 is the same as the distance between the linear protrusion 71 and the impeller 3.

  In Modification 4 and Modification 5, for example, the closest portion 41 may be the winding start portion S, and the plurality of linear protrusions 71 may be located on the radially outer side than the arc R.

[Modification 6 of the second embodiment]
FIG. 21 is a cross-sectional view illustrating Modification 6 of the crossflow fan of the second embodiment. The modification 6 of the second embodiment shown in FIG. 21 is different from the hairy body 52 of the modification 4 of the first embodiment shown in FIGS. The other configurations are the same as those of the fourth modification of the first embodiment shown in FIGS. 8 (A) and 8 (B).

  In the sixth modification of the second embodiment shown in FIG. 21, the backflow suppressing means 70 includes a plurality of hairs 72 extending from the facing surface 40 toward the impeller 3 side, and the hairs on the downstream side in the rotation direction D. The length of the body 72 is configured to be larger than the length of the hair body 72 on the upstream side.

  Specifically, in the modified example 6 of the second embodiment shown in FIG. 21, the lengths of the many hair bodies 72 (lengths toward the impeller 3 side) become longer toward the downstream side in the rotation direction D. However, it is not limited to this. The length of the many hair bodies 72 may be set stepwise (stepwise), for example, so that the downstream hair bodies 72 are larger than the upstream hair bodies 72.

[Modification 7 of Second Embodiment]
FIG. 22 is a cross-sectional view showing Modification 7 of the crossflow fan of the second embodiment. The modification 7 of the second embodiment shown in FIG. 22 is different from the rough surface part 53 of the modification 5 of the first embodiment shown in FIGS. Otherwise, the configuration is the same as that of Modification 5 of the first embodiment shown in FIGS. 9 (A) and 9 (B).

  In the modification 7 of 2nd Embodiment shown in FIG. 22, the backflow suppression means 70 contains the rough surface part 73 which roughened the opposing surface 40 partially, and the downstream part of the rotation direction D in the rough surface part 73 is shown. The surface roughness is configured to be larger than the surface roughness of the upstream portion.

  Specifically, in Modification 7 of the second embodiment shown in FIG. 22, the surface roughness of the rough surface portion 73 increases toward the downstream side in the rotation direction D, but is not limited thereto. The surface roughness of the rough surface portion 73 may be set stepwise (stepwise), for example, so that the downstream portion is larger than the upstream portion. Examples of the surface roughness include calculated average roughness and ten-point average roughness.

[Evaluation results]
FIG. 23 is a graph showing the relationship between the air volume and the static pressure in the cross flow fan 2. In the graph shown in FIG. 23, the horizontal axis represents the air volume Q [m ³ / min], and the vertical axis represents the static pressure Ps [mmAq]. It can be seen that Modification 1 of the second embodiment shown in FIG. 16 is more effective in suppressing surging than the first embodiment shown in FIG. 4 and the reference example shown in FIG. Specifically, it is as follows.

  In FIG. 23, point A is a point when the static pressure becomes unstable when the static pressure is increased in the cross flow fan 2 of the first modification of the second embodiment shown in FIG. . Similarly, the point B is a point when the static pressure becomes unstable when the static pressure is increased in the cross flow fan 2 of the first embodiment shown in FIG. In the cross flow fan of the reference example shown in FIG. 13, this is a point when the static pressure becomes unstable when the static pressure is increased. As described above, in the second embodiment, the maximum static pressure at which the static pressure becomes unstable is larger than those in the first embodiment and the reference example. That is, in the second embodiment, the static pressure is less likely to be unstable than in the first embodiment and the reference example. In the first embodiment, the maximum static pressure at which the static pressure becomes unstable is larger than that in the reference example, and the static pressure is less likely to become unstable than in the reference example. Specifically, in the first modification of the second embodiment in which the protruding lengths of the plurality of linear protrusions 71 toward the impeller 3 side gradually increase toward the downstream side in the rotation direction D, The maximum static pressure is increased by 7.7% compared to the first embodiment in which the protruding length of the linear protruding portion 71 toward the impeller 3 is the same, and the backflow suppression means (linear protruding portion) is improved. The maximum static pressure is increased by 19.2% compared to the reference example not provided.

[Other variations]
As mentioned above, although embodiment of this invention was described, this invention is not limited to these embodiment, A various change, improvement, etc. are possible in the range which does not deviate from the meaning.

  For example, it is possible to combine a plurality of forms selected from the embodiment and the modifications 1-6.

  Moreover, although the said embodiment illustrated the case where the linear protrusion part 51 which comprises the backflow suppression means 5 was provided with two or more, even if the number of the linear protrusion parts 51 which comprise the backflow suppression means 5 is one, it is. Good.

  In the cross-flow fan 2 shown in FIGS. 10A and 10B, among the many protrusions 54, the protrusion 54 on the most downstream side in the rotation direction D has a protrusion length toward the impeller 3 side. It may be configured to be longer than the protruding length to the impeller 3 side. For example, the projecting length of the many protrusions 54 toward the impeller 3 side may be configured to gradually increase toward the downstream side in the rotation direction D.

  FIG. 24A is a cross-sectional view showing a modification of the linear protrusion 51 (71) in the crossflow fan 2 of the first embodiment and the second embodiment, and FIGS. It is an expanded sectional view which shows an example of the shape of the linear protrusion part 51 (71). In the modification of the linear protrusion 51 (71) shown in FIG. 24A, the first surface S1 (the surface S1 on the upstream side in the rotation direction D) facing the impeller 3 (the tip of the blade 31) is On the other hand, the second surface S2 on the downstream side in the rotation direction D has a shape capable of suppressing backflow, while having a shape capable of suppressing interference with the blade 31.

  In the linear protrusion 51 (71) shown in FIG. 24 (B), the first surface S1 has an arc shape in cross section perpendicular to the rotation shaft 3A, and the second surface S2 extends to the rotation shaft 3A. The shape of the cross section orthogonal to is a straight line. In FIG. 24B, the first surface S1 is a convex curved surface that is smoothly curved so as to be positioned downstream in the rotation direction D from the facing surface 40 toward the impeller 3 (for example, a 1/4 arc). In FIG. 24B, the second surface S2 is a surface that rises from the facing surface 40 toward the impeller 3 (specifically, for example, a plane substantially parallel to the radial direction of the impeller 3).

  In the linear protrusion 51 (71) illustrated in FIG. 24C, the first surface S1 is configured by combining a plurality of planes. The first surface S1 is a first plane that stands on the impeller 3 side from the facing surface 40, a second plane that is inclined so as to be positioned downstream in the rotational direction D as it approaches the impeller 3 from the first plane, And a third plane extending downstream from the second plane in the rotation direction D. The second surface S2 is a surface erected from the facing surface 40 toward the impeller 3 (specifically, for example, a plane substantially parallel to the radial direction of the impeller 3).

  In the linear protrusion 51 (71) shown in FIG. 24D, the first surface S1 is a plane that is inclined so as to be positioned downstream in the rotational direction D as it approaches the impeller 3 from the facing surface 40. The second surface S2 is a surface erected from the facing surface 40 toward the impeller 3 (specifically, for example, a plane substantially parallel to the radial direction of the impeller 3).

DESCRIPTION OF SYMBOLS 1 Indoor unit 2 Cross flow fan 3 Impeller 3A Rotating shaft 4 Rear guider 5 Backflow suppression means 6 Stabilizer 7 Heat exchanger 8 Outdoor unit 9 Air conditioner 10 Casing 12 Suction port 13 Outlet 31 Blade 40 Opposite surface 41 Nearest part 51 Linear protrusion 52 Hairy body 53 Rough surface 54 Protrusion 70 Backflow suppression means 71 Linear protrusion D Rotating direction of impeller Fr Backflow

Claims (13)

An impeller (3) having a plurality of blades (31) and rotating in a predetermined rotational direction (D);
A cross flow fan comprising a rear guider (4) having a facing surface (40) opposed to the impeller (3) in the radial direction,
The opposing surface (40) has a closest part (41) closest to the impeller (3),
A gap between the impeller (3) and the closest part (41) is arranged in the rotational direction (41) downstream of the closest part (41) on the facing surface (40) in the rotational direction (D). D) is a crossflow fan provided with a backflow suppression means (5) that suppresses the occurrence of a backflow that is an airflow flowing in the reverse direction.   2. The backflow suppressing means (5) includes one or more linear protrusions (51) that protrude toward the impeller (3) and extend linearly in a direction intersecting with the backflow. Cross flow fan.   The crossflow fan according to claim 2, wherein the intersecting direction is a direction parallel to a rotation axis (3A) of the impeller (3).   The crossflow fan according to claim 2, wherein the intersecting direction is a direction inclined with respect to a rotation axis (3A) of the impeller (3).   The crossflow fan according to any one of claims 2 to 4, wherein a surface of the linear protrusion (51) is a convex curved surface convex toward the impeller (3). The plurality of linear protrusions (51) are:
A first linear protrusion (51);
A second linear protrusion (51) adjacent to the downstream side of the rotational direction (D) with respect to the first linear protrusion (51);
A third linear protrusion (51) adjacent to the downstream side of the rotational direction (D) with respect to the second linear protrusion (51),
The distance between the first linear protrusion (51) and the second linear protrusion (51) is such that the second linear protrusion (51) and the third linear protrusion (51) are spaced apart from each other. The crossflow fan according to any one of claims 2 to 5, wherein the crossflow fan is different from an interval between the crossflow fan and the fan.   The said backflow suppression means (5) contains many hairs (52) extended toward the said impeller (3) side from the said opposing surface (40), Any one of Claims 1-6. Cross flow fan.   The crossflow fan according to any one of claims 1 to 7, wherein the backflow suppressing means (5) includes a rough surface portion (53) obtained by partially roughening the facing surface (40). An impeller (3) having a plurality of blades (31) and rotating in a predetermined rotational direction (D);
A cross flow fan comprising a rear guider (4) having a facing surface (40) opposed to the impeller (3) in the radial direction,
The counter surface (40) is provided with a countercurrent suppression means (70) that suppresses the generation of a countercurrent, which is an airflow flowing in a direction opposite to the rotational direction (D) along the counter surface (40). And
The backflow suppressing means (70) is such that the length toward the impeller (3) in the downstream portion in the rotational direction (D) is longer than the length toward the impeller (3) in the upstream portion. A crossflow fan that is configured to be large.   The backflow suppressing means (70) includes a plurality of linear protrusions (71) that protrude in the direction of intersecting with the backflow while projecting toward the impeller (3), and the plurality of linear protrusions ( 71), the length of the linear protrusion (71) on the most downstream side in the rotational direction (D) is the length of the protrusion to the impeller (3) side of the blade in the other linear protrusion (71). The crossflow fan according to claim 9, wherein the crossflow fan is configured to be longer than a protruding length toward the vehicle (3).   The crossflow fan according to claim 10, wherein a length of the plurality of linear protrusions (71) protruding toward the impeller (3) gradually increases toward the downstream side of the rotation direction (D). .   In a cross section orthogonal to the rotation axis (3A) of the impeller (3), a straight line passing through the winding start portion (S), which is the scroll shape start point on the facing surface (40), and the rotation axis (3A) One straight line (L1), and a straight line passing through the point on the opposite surface (40) downstream of the winding start portion (S) in the rotation direction (D) and the rotation axis (3A) is a second straight line ( L2), when the angle (θ1) formed by the first straight line (L1) and the second straight line (L2) is 45 degrees or less, part or all of the backflow suppression means (5) The crossflow fan according to any one of claims 1 to 11, which is provided.   The indoor unit of the air conditioner provided with the crossflow fan (2) of any one of Claims 1-12.

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