JPH09242694A - Cylindrical impeller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cylindrical impeller in which difference in blasting efficiency due to difference of cross sectional shapes between the root of a blade and the tip thereof, which is generated by draft, is diminished, and also a rasping noise is eliminated. SOLUTION: In a blasting cylindrical impeller in which many blades 3 extended along an axial direction are circumferentially formed on the end surface of a supporting plate at predetermined intervals, a mounting angle of rake against the radial direction of the cylindrical impeller of each blade 3 is gradually changed from θ1 to θ2 from a root 11 to a tip 12, so that difference in blasting efficiency due to difference of cross sectional shapes between the roots 11 of the blades 3 and the tips 12 thereof by draft, is diminished. Also, a ridge line 13 on the peripheral side of each blade 3 is made to have physical relationship that is not to be changed in a straight line, but gradually changed while constantly keeping an interval against the stabilizer 6 of a casing, so that wind is smoothly changed to be led to flow into and out from the blades 3, and an nz sound (rasping noise) is eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylindrical impeller for blowing air such as a cross flow fan used in an air conditioner or the like.

[0002]

2. Description of the Related Art Conventionally, as a cylindrical impeller as described above,
It is known that a predetermined number of elements, each of which has a large number of blades extending straight along the axial direction and formed at predetermined intervals in the circumferential direction, are connected to one end surface of a support plate. This cylindrical impeller will be described below with reference to the drawings. In FIG. 6, reference numeral 1 denotes an element made of a synthetic resin integrally molded product, and a large number of axially extending blades 3 are provided at predetermined intervals in the circumferential direction on one end surface of an annular or disc-shaped support plate 2. It is integrally molded. Each of the blades 3 is formed in a wing-like cross-sectional shape that is inclined with respect to the radial direction of the element 1 and is curved in an approximate arc shape. Further, on the opposite end surface of the support plate 2 where the blades 3 do not extend, there is provided a fitting groove 4 for fitting and fixing the tips of the blades in order to connect another element so as not to be twisted straight. Has been formed.

As shown in FIG. 7, the tips of the blades 3 of the preceding element 1 are fitted and held on the support plate 2 of the following element 1 and fixed by adhesion or ultrasonic welding.
The tubular impeller 5 is configured by repeating the above operation to connect a predetermined number of elements 1 so as not to be twisted in the axial direction, and providing an end plate 2a for fitting and supporting the blade 3 on the tip element 1 ing.

Further, FIG. 8 shows an essential part of a conventional cylindrical impeller from the blade tip 11 to the root 12 of the blade 3 along the axial direction.
It is the enlarged view which looked at. The blade 3 has a root portion 12 arranged at a radius R1 from the center of the tubular impeller 5 at a mounting inclination angle θ1 with respect to the radial direction. Tip 11 of blade 3
Extends straight in the axial direction and is smaller than the root portion 12 by the draft.

Then, as shown in FIG. 9, a cylindrical impeller 5 at the front stage is arranged as a blower for an air conditioner between a stabilizer 6 and a rear guider 7 which form a casing. By rotating the cylindrical impeller in the clockwise direction of arrow 8,
Air flows in from the direction of arrow 9 and flows out in the direction of arrow 10.

[0006]

When the element 1 is arranged to form the cylindrical impeller 5, the number of the blades 3 of the element 1 is z and the number of revolutions per minute is n (n ×). There is a problem that a sound having a frequency of z) / 60 Hz and a sound having a frequency that is an integral multiple thereof are generated. This sound is called a blade pitch sound or an nz sound, and is a sound that feels like hearing a whistle.

Hereinafter, this harsh sound will be referred to as an nz sound. This nz sound is generated by the blades 3 and 3 of the element 1.
The mounting pitch, the shape of the stabilizer 6 and the rear guider 7 and their positional relationship change. For example, if the distance d between the cylindrical impeller 5 and the stabilizer 6 is narrowed in order to improve the blowing efficiency, the nz sound becomes large. in this way,
When trying to increase the air blowing efficiency, there is a problem that the nz sound also becomes loud and the air blowing efficiency cannot be raised to the limit.

Further, the element 1 of the tubular impeller is generally a synthetic resin molded product, but the blade 3 needs a draft to remove the molded element 1 from the mold. As a result, the cross-sectional shape of the tip portion 11 becomes smaller than the cross-sectional shape of the root portion 12 of the blade 3,
There is a problem that the air blowing efficiency differs between the root portion 12 and the tip portion 11 of the blade 3, and the air blowing efficiency cannot be raised to the limit.

The present invention solves the above-mentioned problems, reduces the difference in the air blowing efficiency between the root portion 12 and the blade tip portion 11 of the blade 3, and improves the air blowing efficiency.
An object is to provide a cylindrical impeller without nz sound.

[0010]

According to a first aspect of the present invention, a plurality of blades extending in the axial direction are formed on an end surface of an annular or disc-shaped support plate at a predetermined interval in the circumferential direction. In the impeller, the mounting angle of the blade with respect to the radial direction of the cylindrical impeller is gradually changed from the root to the tip of the blade.

According to a second aspect of the present invention, there is provided a tubular impeller in which a large number of blades extending in the axial direction are formed at predetermined intervals in a circumferential direction on an end surface of the annular or disc-shaped support plate. The mounting position of the blade from the center of the tubular impeller is gradually changed from the root to the tip of the blade.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1 is a perspective view of an element 1 of a tubular impeller according to a first embodiment of the present invention.
Is a tubular impeller 5 in which a plurality of elements 1 shown in FIG. 1 are axially connected to each other and an end plate 2a is provided at a tip portion thereof. This tubular impeller 5 is the same as the conventional one shown in FIGS. 6 and 7, except for each blade 3 provided in each element 1.

FIG. 3 is an enlarged view of the root portion 12 of the blade 3 along the axial direction from the tip 11 side of the blade 3 of the tubular impeller according to the first embodiment. As shown in FIG. 3, in the blade 3 of the first embodiment, the root portion 12 of the blade 3 is arranged at a position of a radius R1 from the center O of the tubular impeller at an attachment inclination angle θ1 with respect to the radial direction, Tip 11 of blade 3
Are arranged at the same radius R1 from the center O of the tubular impeller and at a position extending from the root 12 of the blade 3 by a predetermined distance in the axial direction at a mounting inclination angle θ2 with respect to the radial direction. With these arrangements, the mounting inclination angle of the blade 3 with respect to the radial direction of the cylindrical impeller is gradually changed from the root to the tip, and the outer peripheral ridgeline 13 is formed at the front edge of the blade 3 to be tilted rearward.

Although the single blade 3 is shown in FIG. 3, all the blades of the tubular impeller are gradually changed in inclination angle with respect to the radial direction from the root to the tip in the same manner as the above-mentioned blades. I am allowed.

By configuring the blade 3 as described above, it is possible to reduce the difference in blowing efficiency due to the difference in cross-sectional shape between the root portion 12 and the tip portion 11 of the blade 3 caused by the draft. Further, the distances d1 and d2 between the ridgeline 13 on the outer peripheral side of the blade 3 and the stabilizer 6 forming the casing are equal to each other.
Since d1 = R0-R1 at the position of the root portion 12 and d2 = R0-R1 at the tip portion 11, both d1 and d2 have the same interval. However, when the blade 3 rotates in the clockwise direction shown by the arrow 8, the outer peripheral ridgeline 13 of the blade 3 is not aligned with the stabilizer 6 forming the casing while keeping a constant interval. Construct a positional relationship that changes gradually. Therefore, the inflow 9 of the wind to the blades 3
And the outflow 10 changes smoothly. As a result, the nz sound can be eliminated.

FIG. 4 is an enlarged view of the root portion 12 of the blade 3 along the axial direction from the tip 11 side of the blade 3 of the tubular impeller according to the second embodiment. As shown in FIG. 4, in the blade 3 of the second embodiment, the root portion 12 of the blade 3 is arranged at a position of a radius R1 from the center O of the tubular impeller at a mounting inclination angle θ1 with respect to the radial direction, Tip 11 of blade 3
At a position with a radius R2 different from the center O of the cylindrical impeller,
It is arranged at a position extending from the root portion 12 by a predetermined distance in the axial direction at different mounting inclination angles θ3 with respect to the radial direction. With these arrangements, the mounting position of the blade 3 from the cylindrical impeller center O is gradually changed from the root to the tip, so that the blade 3 is tilted outward.

Although only one blade 3 is shown and described in FIG. 4, all the blades of the tubular impeller are gradually changed in mounting position from the root to the tip like the above-mentioned blades. The configuration other than the blades is the same as the conventional one shown in FIGS. 6 and 7.

By configuring the blades 3 as described above, it is possible to reduce the difference in blowing efficiency due to the difference in cross-sectional shape between the root portion 12 and the tip portion 11 of the blades 3 caused by the draft. Further, the distances d1 and d2 between the ridgeline 13 on the outer peripheral side of the blade 3 and the stabilizer 6 forming the casing are equal to each other.
D1 = R0-R1 at the position of the root portion 12 of the blade 3
D2 = R0-R2 at the tip 11 of the. The outer peripheral ridgelines 13 of the blades 3 are aligned on a straight line in the positional relationship with the stabilizer 6 forming the casing.
Since the interval is gradually changed from the root 12 to the tip 11 of the blade, the blade 3 rotates clockwise in the direction indicated by the arrow 8 so that the inflow 9 and the outflow 10 of the wind to the blade 3 are smooth. Changes to. As a result, the nz sound can be eliminated.

FIG. 5 is an enlarged view of the root portion 12 of the blade 3 along the axial direction from the tip 11 side of the blade 3 of the tubular impeller according to the third embodiment. As shown in FIG. 5, in the blade 3 of the third embodiment, the root portion 12 of the blade 3 is arranged at a position of a radius R1 from the center O of the tubular impeller, at a mounting inclination angle θ1 with respect to the radial direction, Tip 11 of blade 3
At a position with a radius R2 different from the center O of the cylindrical impeller,
It is arranged at a position extending from the root portion 12 by a predetermined distance in the axial direction at different mounting inclination angles θ4 with respect to the radial direction. By these arrangements, the mounting inclination angle of the blade 3 with respect to the radial direction of the tubular impeller and the center O of the tubular impeller are set.
From the root portion to the tip portion, and the outer edge line 1 is inclined rearward to the front edge of the blade 3.
3 and the blade 3 is tilted outward.
The configuration of the blade of the third embodiment is a configuration including the configuration of the blade of the first and second embodiments shown in FIGS. 3 and 4 together.

Although only one blade 3 is shown in FIG. 5, all the blades of the cylindrical impeller are similarly changed in inclination angle and attachment position from the root to the tip. The configuration other than the blades is the same as the conventional one shown in FIGS. 6 and 7.

By configuring the blade 3 as described above, it is possible to reduce the difference in blowing efficiency due to the difference in cross-sectional shape between the root portion 12 and the tip portion 11 of the blade 3 caused by the draft. Further, the distance between the outer peripheral ridgeline 13 of the blade 3 and the stabilizer 6 forming the casing is d1 = R0-R1 at the position of the root portion 12, and d at the tip portion 11 of the blade 3.
2 = R0-R1. However, the outer ridge line 1 of the blade 3
3 does not have a positional relationship with the stabilizer 6 that constitutes the casing in a straight line, and the blade 3 rotates in the clockwise direction shown by an arrow 8 to form a positional relationship in which the interval gradually changes. The inflow 9 and the outflow 10 of the wind change smoothly. As a result, the nz sound can be eliminated.

In the present invention, in each of the above-described embodiments, a plurality of elements are connected in the axial direction to form a cylindrical impeller, but an end plate is attached to the tip of the blade of one element to form a cylindrical impeller. You may comprise an impeller.

[0023]

As described above, the cylindrical impeller according to the invention of claim 1 has a large number of blades extending in the axial direction from the end surface of the support plate, and the cylindrical shape of these blades. Since the mounting inclination angle of the impeller with respect to the radial direction is gradually changed from the root part to the tip part, the difference in blowing efficiency due to the difference in cross-sectional shape between the root part of the blade and the tip part of the blade caused by the draft By reducing the amount, the blowing efficiency can be improved. Further, since the outer peripheral ridge of the blade forms a positional relationship with the stabilizer that constitutes the casing while maintaining a constant distance, it does not form a straight line but a gradually changing positional relationship. The outflow changes smoothly. As a result, it is possible to eliminate the unpleasant nz sound.

The cylindrical impeller according to the invention of claim 2 has a large number of blades extending in the axial direction from the end surface of the support plate, and these blades are arranged from the center of the cylindrical impeller. Since the mounting position is gradually changed from the root to the tip of the blade, the difference in the ventilation efficiency due to the difference in the cross-sectional shape of the blade root and the blade tip caused by the draft is reduced, and the ventilation efficiency is improved. Can be improved. In addition, the outer peripheral ridges of the blades are aligned in a straight line with the stabilizers that form the casing, but since the gaps form a positional relationship that gradually changes, the flow of air into and out of the blades is smooth. Changes to. This makes it possible to eliminate the nz sound that is unpleasant to the ear.

[Brief description of drawings]

FIG. 1 is a perspective view showing an element of a tubular impeller according to a first embodiment of the present invention.

FIG. 2 is a partially cutaway perspective view showing a tubular impeller according to the first embodiment of the present invention.

FIG. 3 is an enlarged view of the blade root of the tubular impeller shown in FIG. 2 as viewed from the tip of the blade along the axial direction.

FIG. 4 is an enlarged view of the blade root of the tubular impeller according to the second embodiment of the present invention, as viewed from the tip of the blade along the axial direction.

FIG. 5 is an enlarged view of the blade root of the tubular impeller according to the third embodiment of the present invention, as viewed from the tip of the blade along the axial direction.

FIG. 6 is a perspective view showing an element of a conventional tubular impeller.

7 is a partially cutaway perspective view of a conventional tubular impeller in which the elements shown in FIG. 6 are connected.

FIG. 8 is an enlarged view of the blade root of the tubular impeller shown in FIG. 7 as viewed from the tip of the blade along the axial direction.

FIG. 9 is an explanatory cross-sectional view showing the positional relationship between the cylindrical impeller and the casing in the air conditioner.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Element 2 Support plate 3 Blade 4 Fitting groove 5 Cylindrical impeller 6 Stabilizer 7 Rear guider 8 Rotating direction of cylindrical impeller 9 Inflow direction 10 Outflow direction 11 Blade tip 12 Blade root 13 Blade outer edge line

Claims (2)

[Claims] 1. A cylindrical impeller in which a large number of blades extending in the axial direction are formed at predetermined intervals in the circumferential direction on an end surface of an annular or disc-shaped support plate, and the cylindrical impeller of the blades. A cylindrical impeller characterized in that the mounting angle with respect to the radial direction is gradually changed from the root part to the tip part of the blade. 2. A tubular impeller in which a large number of blades extending in the axial direction are formed at predetermined intervals in the circumferential direction on an end surface of the annular or disc-shaped support plate. A cylindrical impeller characterized in that the mounting position from the car center is gradually changed from the root to the tip of the blade.