JP4611336B2 - Side cut fan - Google Patents

Description

  The present invention relates to a venturi wind tunnel shape of an axial fan, particularly a side cut fan.

JP 2001-182698 A) (JP 2002-089496 A)

Although details are omitted in the description of each of the above-mentioned patent documents, various studies have been tried and put into practical use with regard to the venturi shape of the venturi in order to cope with conflicting elements of improvement in air blowing performance and quietness. Thus, the so-called side cut fan according to the present invention intended to suppress the mounting space is still within the applicable range.

The side cut fan itself also has the purpose of maintaining rigidity as a countermeasure for the thinning of the venturi associated with the formation of the cut-out portion, and the venturi inner peripheral surface forming the wind tunnel has an initial wind-tunnel inner circular arc at the cut-off portion. It is also well known that the curvature diameter is different from the arc diameter of the surface so that the gap between the propeller and the rotating outer peripheral arc surface of the propeller can be reduced and communicated.

However, in the side cut fan, as described above, in addition to the improvement effect of the prior art, the arc communication portion on the inner peripheral surface of the venturi corresponding to the side cut portion has an original wind tunnel from the straight inlet edge. There is a need for a solution to noise due to pressure fluctuations resulting from the formation of a gradually changing curved surface up to an arc diameter different from the initial arc diameter forming the inner circumferential arc surface.
This appears as a frequency component resulting from the number of propeller blades and the rotational speed at two side cut surfaces, and is a dominant sound source for noise in the entire frequency band.

The side cut fan according to the present invention is configured so that the air tunnel inner circumferential surface arc communication portion at the side cut portion is a wide region corresponding to the entire side cut portion, from the vicinity of both ends of the suction side linear edge. , Through the inclined conical surface toward the discharge port side arc surface, is formed as a smooth shape that smoothly expands while gradually changing the curvature,

A wide smooth shape surface corresponding to the entire side cut portion on the inner surface of the side cut portion is formed symmetrically in the circumferential direction.

The side-cut fan according to the present invention is a unique problem in the side-cut fan, which is a change in the gap between the outer peripheral circular arc surface of the propeller and the arc diameter change of the inner peripheral surface of the wind tunnel due to excision of the outer peripheral surface of the venturi. The effect of suppressing the influence of pressure interference between the propeller and the inner peripheral surface of the wind tunnel is realized.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a front view (a) and a perspective view (b) showing an embodiment of a venturi according to the present invention, and FIG. 2 is a front view (a) and a perspective view showing an example of a venturi in the prior art. b).

As shown in FIG. 2, the venturi 1 according to the prior art has an inner peripheral surface of the side cut portion 2 formed so as to be opposed to the outer peripheral surface by being shifted by 180 degrees, and the outer peripheral surface of the side cut portion 2 is cut away. In order to ensure the strength of the housing, the suction port side straight edge 5 is provided at the suction port side end edge to secure the wall thickness, and the straight portion (5) The propeller (not shown) on the inclined conical surface / discharge port side circular arc surface is formed so as to be connected to the circular arc communication portion 4 in consideration of a small gap change with the rotating outer peripheral circular arc surface.

On the other hand, in the present invention shown in FIG. 1, from the vicinity of both ends in the circumferential direction of the suction port side linear end edge 5 corresponding to the side cut portion 2 to the arc communication portion (4) in the entire inner surface corresponding to the side cut portion 2. It is formed as a wide smooth shape surface 6 that expands smoothly with gradually changing curvature.

From the conventional idea for the purpose of ensuring a balance between performance and noise by reducing the change in the gap between the inner peripheral surface of the wind tunnel and the rotating outer peripheral arc surface of the propeller, from the suction port side to the discharge port side in the side cut portion 2 In view of the transition to the smooth ventilation of the wind tunnel, the present inventors have reached the present invention by repeatedly studying the shape of the inner peripheral surface of the wind tunnel.

The side-cut fan according to the present invention suppresses the influence of pressure interference without enlarging the mounting space, and can ensure the ventilation performance, so the use of the side-cut fan as a space-saving axial fan is expanded. Is possible.

It is the front view (a) and perspective view (b) explaining the venturi of the example of the side cut fan concerning this invention. It is the front view (a) and perspective view (b) explaining the venturi of the example of the side cut fan used as a prior art. It is a comparison data of the ventilation performance of the example of the axial flow fan comprised by the example of FIG. 1 and FIG. 2, and a noise. It is frequency analysis data corresponding to the overall noise data shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Venturi which forms the wind tunnel of an axial fan 2 Side cut part 3 Wind tunnel part initial circular arc surface 4 Arc communication part of side cut part inner surface 5 Inlet side linear edge of side cut part inner surface 6 Side cut which concerns on this invention Inner circular arc surface that smoothly expands toward the discharge port side from the vicinity of both ends in the circumferential direction of the suction port side linear end edge

Claims (2)

An axial fan having a cylindrical venturi that forms a wind tunnel inside and a propeller disposed in the wind tunnel, and due to restrictions on mounting space, a circular arc is cut into a part of the venturi to form a string In a side cut fan provided with a flat side cut portion, a straight end edge is formed at the opening end of the venturi at the opening end of the venturi. Except for the cut portion, an inclined surface that guides the air flow is formed continuously in the circumferential direction, and an inner peripheral surface corresponding to the side cut portion of the opening in the venturi is formed around the inclined surface. said straight edge smooth curved surfaces toward the interior venturi from the edge smoothly shaped surface that continuously is formed with a curved shape in the direction gradually changes continuously Side cut fan, characterized. Wherein the venturi is formed in a position where the side cut portion of the pair are opposed 180 degrees, according to claim 1, wherein the smooth-shaped surface corresponding to the side cutting portion, characterized in that you are formed symmetrically shaped Side cut fan as described in.