JP2000329367A - Crossflow fan - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stabilize the position of a re-circulating vortex and reduce the size of the same by a method wherein the opposing surface of a stabilizer is provided with a projected part, projected toward an impeller, at the intermedi ate position in the widthwise direction of the same. SOLUTION: A stabilizer 20 is provided with an opposing surface 21, opposed to the outer periphery of an impeller 3 with a space, while the opposing surface 21 is provided with a projected part 22, projected toward the impeller 3, at an intermediate position in the widthwise direction of the opposing surface 21. In this case, upon rotating the impeller 3, a re-circulating vortex 6, formed in conjunction with the stabilizer 20, is formed stably at a predetermined position by the effect of the projected part 22 and the size of the vortex is also reduced. A distance δ between the tip end 23 of the opposing surface 21 and the outer periphery of the impeller 3 can be provided sufficiently whereby a suction area can be retained so as to be large enough. Accordingly, not only the amount of suction air can be secured sufficiently but also the flow rate distribution 9 of air, passed through a heat exchanger 5 arranged at the upstream of a suction side, is unified.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cross flow fan used for an indoor unit of an air conditioner and the like.

[0002]

2. Description of the Related Art A cross-flow fan shown in FIG. 4 has been disclosed in Japanese Utility Model Laid-Open No. 4-65990 in order to prevent surging of the cross-flow fan and reduce noise.

In this cross flow fan, a vortex stabilizing guide member 10 is provided on the stabilizer 1, and a concave portion is provided between an upper surface 13 of the stabilizer 1 and a surface 14 of the vortex stabilizing guide member 10 facing the impeller 3. A triangular vortex stabilizer 11 is formed. In FIG. 4, 2 is a back casing,
7 is a suction side, and 8 is an outlet side.

[0004]

In the conventional cross flow fan, when the tip 12 of the guide member 10 for vortex stabilization is too close to the impeller 3, the flow passing between the blades 4 of the impeller 3 and the vortex stability As shown in FIG. 5, the nz sound generated by the interference with the guide member 10, that is, the rotational frequency noise becomes remarkable as a peak noise, and there is a problem that it is annoying. On the other hand, if the tip 12 of the vortex stabilizing guide member 10 does not approach the impeller 3 sufficiently, the recirculation vortex 6 becomes large and the recirculation vortex 6 becomes unstable.

[0005] When the recirculation vortex 6 becomes large, the suction area becomes small, and the drift in the flow velocity distribution 9 of the airflow passing through the heat exchanger 5 provided upstream of the suction side 7 becomes large. As a result, there arises a problem that the rotational frequency noise generated due to the interference between the drift and the blade 4 of the impeller 3 becomes annoying and at the same time a sufficient intake air volume cannot be secured.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and its gist is to provide an impeller having an opposing surface facing an outer periphery of the impeller with a gap therebetween. A cross-flow fan equipped with a stabilizer that cooperates with the impeller to form a recirculating vortex when the impeller rotates,
A cross flow fan, wherein a protrusion protruding toward the impeller is provided at an intermediate position in the width direction of the opposing surface of the stabilizer.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention is shown in FIG. In FIG. 1, reference numeral 2 denotes a back casing, 3 denotes an impeller, 4 denotes a blade, 5 denotes a heat exchanger, 7 denotes a suction side, 8 denotes an outlet side, and these are the same as the conventional one shown in FIG.

Reference numeral 20 denotes a stabilizer, which has an opposing surface 21 opposing the outer periphery of the impeller 3 with a gap therebetween. A convex portion 22 protruding toward the impeller 3 is provided at an intermediate position in the width direction of the facing surface 21.

Thus, when the impeller 3 rotates, the recirculation vortex 6 formed in cooperation with the stabilizer 20 is stably formed at the position shown in the figure by the action of the projection 22, and its size is reduced. In addition, since the distance δ between the tip 23 of the facing surface 21 and the outer periphery of the impeller 3 can be sufficiently taken, the suction area can be kept large.

Therefore, not only can the suction air volume be sufficiently ensured, but also the flow velocity distribution 9 of the air passing through the heat exchanger 5 arranged upstream of the suction side 7 is made uniform.

In this way, the recirculation vortex 6 can be reduced and its position can be stabilized, and the flow velocity distribution of the air passing through the heat exchanger 5 can be made uniform. Rotational frequency noise, that is, nz noise, generated by interference between the airflow sucked into the blade 3 and the blade 4 of the impeller 3 can be reduced.

[0012] As shown in FIG.
The distance a from the projection 23 to the projection 22, the height h of the projection 22, and the width w of the projection 22 are major factors that affect the nz sound. Experiments have shown that a is 5 to 10 mm and h is 0.5 to 0.5. 5mm, w is 1-5
The effect is large in the range of mm, and as shown in FIG.
10 to 15 dB could be reduced.

In the experiment, the cross-sectional shape of the projection 22 was rectangular. However, the shape is not limited to a rectangle, but may be a trapezoid, a triangle, a semicircle, or an oval. In addition, the experiment was performed with stabilizer 20
The projections 22 were continuous over the entire length of the sample and the distance a was constant. However, even if the projections 22 were slightly inclined, or were intermittent along the longitudinal direction, Convex part 22
May be slightly different from each other.

[0014]

According to the present invention, since the convex portion protruding toward the impeller is provided at the intermediate position in the width direction of the opposing surface of the stabilizer, the position of the recirculation vortex can be stabilized and its size can be reduced. Can be smaller. Also,
Since the distance between the tip of the opposing surface and the outer periphery of the impeller can be sufficiently taken, the suction area can be kept large and the suction air volume can be sufficiently ensured.

As a result, the position of the recirculation vortex can be stabilized and its size can be reduced, and the flow velocity distribution of the air passing through the heat exchanger can be made uniform. It is possible to reduce rotational frequency noise caused by interference between the sucked airflow and the blade.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a main part of a cross flow fan according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a stabilizer of the cross flow fan.

FIG. 3 is a diagram showing a noise distribution of the cross flow fan.

FIG. 4 is a sectional view showing a main part of a conventional cross flow fan.

FIG. 5 is a diagram showing a noise distribution of a conventional cross flow fan.

[Explanation of symbols]

 3 impeller 4 blade 5 heat exchanger 7 suction side 8 outlet side 20 stabilizer 21 opposing surface 22 convex part 23 tip

Continuation of the front page (72) Inventor Kenji Ito 3-chome, Asahicho, Nishi-Biwajima-cho, Nishi-Kasugai-gun, Aichi Prefecture Inside the Air Conditioning Works of Mitsubishi Heavy Industries, Ltd. (72) Inventor Masato Shimo 3--18 Marunouchi, Naka-ku, Nagoya City, Aichi Prefecture No. 28 F-term in Japan Techseed Co., Ltd. (Reference) 3L049 BB04 BB08 BC01 BD02

Claims (1)

[Claims] 1. A cross-flow fan comprising a stabilizer having an opposing surface facing an outer periphery of an impeller with a gap therebetween and forming a recirculation vortex in cooperation with the impeller when rotating. A cross-flow fan provided with a projection protruding toward the impeller at an intermediate position in the width direction of the opposing surface of the cross flow fan.