JPS61107000A - Sirocco fan - Google Patents

Abstract

PURPOSE:To improve the blast efficiency of a sirocco fan by inclining each of a plurality of blade sections on the same circle centered on the axis of rotation in the direction reverse to that the impeller rotation as viewed from a boss portion torward a support ring. CONSTITUTION:In a sirocco fan, each of a plurality of blades 1a arranged between a boss portion 6 and a support ring 5 has a section gently inclined toward the support ring 5 from the boss portion 6. Accordingly, in the clockwise rotation of an impeller 1, the blades 1a supplies a fluid with a force in the axial direction from the boss portion 6 toward the support ring 5 as well as the one in a plane vertical to the axis of rotation. This moves the whole fluid flowing out of the impeller 1 toward the support ring side, reducing a dead fluid region to improve the blast efficienty of the fan.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a sirocco fan used in small air conditioners and the like.

2. Description of the Related Art The structure of a conventional conventional sirocco fan will be explained with reference to FIGS. 5 and 6. An impeller 7 having blades 7a arranged parallel to the rotation axis between a boss portion 9 and a retaining ring 8 is housed in a fan casing 2 equipped with a bell mouth 3, and is driven by a motor 4 to rotate as shown in FIG. The flow shown by A is produced.

The flow indicated by arrow A flows around the bell mouth and therefore does not flow in a plane perpendicular to the axis, but has an axial velocity component moving from the retaining ring side to the boss side. Therefore, the flow passing through the region B on the retaining ring side of the impeller decreases, forming a dead water region C. Therefore, the actual flow path at the impeller outlet is narrower than the blade height.

Problems to be Solved by the Invention As described above, since there is a dead water region with an extremely low flow rate on the retaining ring side of the impeller, the effective height of the blades becomes short, causing a reduction in air blowing performance.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention holds one end of a plurality of blades arranged in an annular manner with a retaining ring, provides a boss portion at the other end, and rotates the blades around the rotation axis. The cross-sectional shape of the plurality of blades at the same radial position is inclined from the boss side toward the retaining ring side in a direction opposite to the impeller rotation direction.

Operation By adopting the above-mentioned configuration, the fluid passing through the blades is given not only a force in a plane perpendicular to the axis of rotation, but also a force in the direction of the axis of rotation. That is, as shown in Fig. 3, if the angle that the circumferential cross section of the blade represents with the rotational axis direction is ξ, then the force F that the blade exerts on the fluid is of the magnitude)" a si
It has an axial component of nξ.

In this case, when passing through the blades, the flow is given a velocity component in the axial direction from the boss side to the retaining ring side, so the entire flow moves from the boss side to the retaining ring side, and the dead water area on the retaining ring side is small. Become.

Therefore, the effective height of the impeller increases and the air blowing performance improves.

Example Embodiments of the present invention will be described below with reference to FIGS. 1 and 2.

The blades 1a arranged between the boss portion 6 and the retaining ring 5 are
It has a shape that slopes smoothly from the boss side to the retaining ring side. When this impeller is rotated clockwise, the impeller exerts an axial force on the fluid from the boss side toward the retaining ring □ side as well as a force in the plane perpendicular to the axis, causing the fluid to flow out of the impeller. The entire flow moves toward the retaining ring side, and the dead area that conventionally existed toward the retaining ring side becomes smaller, improving air blowing efficiency.

The slanted shape of the blade is not limited to the shape shown in Figure 2.
Similar effects can be obtained by using a vane shape as in the other embodiment of the present invention shown in FIG. 4, and the optimum shape is determined in relation to the casing shape.

Effects of the Invention As described above, the scirocco fan of the present invention moves the entire flow from the boss side to the retaining ring side by tilting the blade shape from the boss side to the retaining ring side in the opposite direction to the rotation direction. This increases the effective height of the blades and improves air blowing performance.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional side view of the casing of a scirocco fan showing an embodiment of the present invention, Fig. 2 is a perspective view of the scirocco fan, and Fig. 3 is a cylindrical surface of the scirocco fan centered on the rotation axis. FIG. 4 is a perspective view of a scirocco fan showing another embodiment of the present invention, FIG. 5 is a side view of a conventional scirocco fan with the casing taken in section, and FIG.
The figure is a perspective view of the sirocco fan. DESCRIPTION OF SYMBOLS 1... Impeller, 1a... Vane, 3... Bell mouth, 5... Retaining ring, 6... Boss part. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
figure! ----- Habu Abei Figure 2! Figure 3 Figure 4' 6 1, , /- To 1 Figure 5 Figure 6

Claims (1)

[Claims] One end of a plurality of blades arranged in a ring is held by a retaining ring, a boss is provided at the other end, and the cross-sectional shape of the plurality of blades at the same radial position around the rotation axis is viewed from the boss side to the retaining ring side. A sirocco fan tilted in the opposite direction to the direction of blade rotation.