JPS61123345U - - Google Patents

Description

[Brief explanation of the drawing]

Figure 1 is a sectional view of a ventilation fan according to an embodiment of this invention, Figure 2 is a front view of the impeller of the ventilation fan, and Figure 3 is a front view of the impeller of the ventilation fan.
FIG. 4 and FIG. 4 are characteristic diagrams based on experimental results showing the values of the noise level and specific noise level with respect to changes in M/lz ₁ of the ventilation fan. 1... Outer frame, 2... Bell mouth, 3... Impeller, 4... Vane, 5... Boss section, 6... Motor, 7
...Mounting foot, DT...Blade outer diameter, lz ₁ ...0.
9. Axial dimension of impeller at DT position, P... lz ₁ point closest to the mounting foot, M... Distance between point P and the mounting foot. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims for Utility Model Registration] An outer frame with openings on the indoor and outdoor sides, and an inner peripheral surface provided at the front of the outer frame that gradually reduces in diameter toward the rear to form a tapered wind tunnel. The bell mouth of the blade, the chord line center point _P1 in the cross section when cut through a cylindrical surface with radius R centered around the rotation axis, and the wing in the cross section when the boss part of the blade is cut through the cylindrical surface with radius Rb. When the distance between the chord line center point Pb and the plane Sc that is perpendicular to the axis of rotation is ls, in a coordinate system with the suction direction of the airflow as the positive direction, _point P is always located in the positive direction with respect to the Sc plane. and the value of δz that can be expressed as δ _z = tan ⁻¹ lsR−Rb is δz = 12.5° ~ 32
．． 5°, and on the projection plane when the blade surface is projected onto a plane orthogonal to the rotation axis, the chord line center point P in the cross section when the boss part of the blade is cut by a cylindrical surface with radius Rb, and the rotation In a coordinate system where the axis is the origin O and the straight line connecting the O point and the Pb' point is the X axis, the chord line center point when the blade surface is cut by a cylindrical surface with a radius R is P1 _' , and the straight line P is When the angle between _1' -O and the X axis is δθ, the radial distribution of δθ is δθ = (δθ _t −δθ _b )
-Rb)+δθ _b (Rt: Blade outer diameter radius, Rb: Blade boss radius)
Given by, δθ _t = 46° to 50°, δθ _b = −5
In a developed view obtained by cutting the blade surface with a cylindrical surface of radius R and developing the cross section into a two-dimensional plane, the shape of the warp line in the blade cross section is an arc shape, and When the central angle for forming an arc is θ, the radial distribution of θ is θ=(θ _t −θ _b )×(R−Rb)(Rt−Rb
)+θ _b , θt=20°~30°, θb=27°~
37°, θt<θb, and in the developed view,
When the angle between the chord line of the blade and a straight line parallel to the axis of rotation and passing through the leading edge of the blade is ξ, the radial distribution of ξ is ξ = (ξt - ξb) x (R - Rb) (Rt -Rb
)+ξb, ξt=62°~72°, ξb=53°~
63°, ξt<ξb, and in the developed view,
When the chord length of the blade is l, the pitch at the same radius point between blades is t, the ratio of t/l at each radius point is t/l = 1 to 1.1, and the number of blades is N. In a ventilation fan equipped with an impeller having four blades, a motor that drives the impeller, and four mounting legs that fix the motor, the blade outer diameter is 90% of the blade outer diameter DT of the impeller. A ventilation fan characterized in that the distance M between the axial dimension lz ₁ of the impeller at the 0.9DT position and the point P closest to the mounting foot of the axial dimension lz ₁ of the impeller and the mounting foot is set to M≧0.65lz ₁ . .