JPH04187899A - Axial blower - Google Patents

Abstract

PURPOSE:To develop blowing performance and to prevent noise by extending outward the outer circumference of each blade on the blowing-out side of a blower in a triangular shape while keeping a prescribed space with the blowing- out port of the orifice. CONSTITUTION:The outer circumference 2c of a blade 2b on the blowing-out side of an axial blower is extended nearly in a triangular shape while keeping a prescribed space with the wall surface of the blowing-out port of the orifice 3. Since the gap between the outer circumference 2c of the blade and the blowing-out port of the orifice is not widened, and also the positive pressure side and the negative pressure side of the blade 2b are not exposed, back flow can be prevented, and the reduction in performance and the increase in noise can be restrained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an axial blower mainly used in an outdoor unit of a separate type air conditioner.

(Prior Art) In recent years, axial flow blowers have been widely used as blowers for outdoor units of separate air conditioners, from commercial to home use, and there is a desire for lower noise.

A conventional axial flow blower will be explained with reference to FIGS. 3 to 5, taking as an example the proposal of Japanese Utility Model Application Laid-Open No. 62-105432.

FIG. 3 and FIG. 4 are a front view and an enlarged plane cross-sectional view of essential parts showing the structure of a conventional axial flow blower.

A conventional axial flow blower includes a main body 1, an impeller 2 arranged inside the main body 1 and having a plurality of blades 2b around a hub 2a, and a structure that surrounds the outer periphery of the impeller 2. It consists of an annular orifice 3 integrally formed and an electric motor 4 that rotates an impeller 2.

Note that the orifice 3 described above is a bell mouth-shaped suction port 3.
a, and an air outlet 3b that extends in a trumpet shape from the minimum inner diameter of the air inlet 3a toward the air outlet direction.

The operation of the axial blower configured as above will be explained.

When the impeller 2 is driven by the electric motor 4 and rotates in a predetermined direction, static pressure and dynamic pressure are generated by the blowing action, and the outside air is
The liquid is sucked into the machine and discharged through the orifice 3 to the outside of the machine.

(Problem to be Solved by the Invention) However, in the above configuration, the impeller 2 is arranged such that its front end is flush with the front surface of the main body l, so the minimum inner diameter of the orifice 3 is The portion faces the inner side of the front end of the vane 2b having a threaded outer circumferential end.

Therefore, ahead of this, the gap between the blade 2b and the air outlet 3b gradually becomes wider.

When the trickle blower is used under conditions where the ventilation resistance becomes large, the axial velocity component decreases and the radial velocity component increases, as shown in the velocity vector diagram shown in FIG. Outer peripheral end 2C of the blade 2b on the outlet side and the outlet 3 of the orifice 3
The gap in the wall b gradually increases in the blowing direction, and the positive pressure side and negative pressure side of the blade 2b are exposed, so there is a problem that the air flows back to the negative pressure side, reducing the air blowing performance and increasing noise due to turbulence sound. there were.

The present invention solves the above problems and provides a low-noise axial flow blower that does not cause backflow at the outer peripheral end 2C of the impeller 2 near the outlet of the orifice.

(Means for Solving the Problems) In order to solve the above problems, the present invention extends the outer circumferential end 2c of the blade 2b on the blowout side to the outside so as to have a certain gap with the air outlet 3b of the orifice 3. It is something to do.

(Function) With the above configuration, the positive pressure surface and the negative pressure surface are not exposed at the outer circumferential end 2c on the blowing side of the blade 2b, so that a part of the airflow blown out does not flow back to the negative pressure surface side. Therefore,
Air blowing performance does not deteriorate and noise does not increase.

(Example) An example of the present invention will be described with reference to FIGS. 1 and 2.

1 and 2 are a front view and an enlarged plan sectional view of the main parts showing the structure of an axial blower according to the present invention, and show the differences between this embodiment and the conventional example shown in FIGS. 3 and 4. connects the outer circumferential end 2C of the blade 2 to the outlet 3 of the orifice 3.
It is a point extended in an almost triangular shape so as to maintain a certain gap with the wall surface of b. Since the rest is the same as the conventional example, the same components are given the same reference numerals and their explanations will be omitted.

The operation of the axial blower configured as above will be explained.

Even if the flow is inclined toward the outer circumference due to the installation conditions where the ventilation resistance of the axial blower becomes large, the gap between the outer circumference end 2C on the outlet side of the blade 2b and the outlet 3b of the orifice 3 does not widen, and the Since the pressure side and the negative pressure side are not exposed, the flow does not flow back to the negative pressure side, thereby suppressing a decrease in air blowing performance and an increase in noise due to turbulent sound.

(Effects of the Invention) As explained above, according to the present invention, a predetermined air blowing performance is always exhibited regardless of the installation conditions of equipment incorporating an axial blower, and noise due to turbulence is generated. This results in an axial blower that does not.

[Brief explanation of drawings]

1 and 2 are a front view and an enlarged plan sectional view of the main parts of an axial flow blower according to the present invention, and FIGS. 3 and 4 are a front view and an enlarged plan sectional view of the main parts of a conventional axial flow blower. , FIG. 5 is a velocity vector diagram showing the results of measuring the flow between clouds of a conventional axial flow blower. l...Main body, 2...Impeller, 2a...Hub, 2b...Blade, 2c...Blowout side outer peripheral end,
3... Orifice, 3a... Suction port, 3b
...Air outlet, 4...Electric motor.

Claims (1)

[Claims] At least an impeller in which a plurality of blades are installed around a hub, and an annular orifice blade provided surrounding the impeller and having a blowout port that gradually widens in the blowout direction, the outer circumferential end on the blowout side; An axial flow blower characterized in that the orifice has an approximately triangular extension so as to maintain a certain gap with the wall surface of the outlet.