JPS648199B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to improving the blowing performance and reducing operating noise of centrifugal blowers used in air conditioners and the like.

Conventional structure and its problems Conventionally, in order to improve the air blowing performance of a centrifugal blower, the shape of the spiral casing was changed by increasing the radial distance in proportion to the rotation angle in the rotation direction of the multi-blade impeller, and It has been known that it is effective to provide an inclined portion and increase the axial distance in proportion to the rotation angle. That is, as shown in FIG. 1, the casing radius b is increased in proportion to the rotation angle along the rotational direction x of the impeller from the tongue a closest to the impeller (not shown) in the radial direction, An inclined portion d having a constant angle is provided on the air suction surface c, and the shape is such that the axial distance u increases in proportion to the rotation angle.

However, this shape has a problem in that the axial distance v of the spiral ending portion e becomes large, and the equipment such as an air conditioner in which this centrifugal blower is incorporated becomes large. Furthermore, for ease of construction of an air conditioner, etc., and for aesthetic purposes, the shape of the air blowing part f is required to have a rectangular cross section, but the flow path cross section of the spiral part end part e is a square corner shape. In order to gently transform this into a rectangular cross section while suppressing air turbulence, the length w of the blowout passage becomes large. This also poses a problem in that it increases the size of the equipment in which the centrifugal blower is incorporated.

Purpose of the Invention The present invention solves these problems, and aims to improve the blowing performance of a centrifugal blower, reduce noise, and enable it to be incorporated into small equipment. It is something.

Structure of the Invention In order to achieve this object, the present invention provides a casing of a centrifugal blower with an inclined part at a constant angle up to the middle of the spiral, similar to the conventional example, and a shape in which the distance in the axial direction increases. The distance is constant, and the slope angle of the slope is increased in order to increase the cross-sectional area in proportion to the rotation angle.

When a centrifugal blower with this configuration is operated, the air flowing out from the multi-blade impeller flows into a sufficiently secured flow path from the start point to the end point of the vortex, improving the blowing performance and reducing the axial distance. small,
Furthermore, since the cross-sectional shape of the spiral end portion is nearly rectangular, the length of the blowout portion in the ventilation direction can also be reduced.

DESCRIPTION OF EMBODIMENTS The present invention will be described below with reference to FIGS. 2 to 4 showing one embodiment thereof.

In FIGS. 2 to 4, 1 is an impeller, and 2 is a drive shaft fixed to the impeller 1. 3 is a spiral surface of the casing, and 4 is a side surface of the casing, on which a nozzle 5 is disposed. Reference numeral 6 denotes an air outlet, which has a rectangular cross-sectional shape. FIG. 3 shows a sectional view of FIG. 4 taken along line X-X'. In Fig. 3, the spiral surface 3 is arranged so that the radial length (radius R) increases in proportion to the rotation angle along the rotation direction M of the impeller 1 from the spiral starting point 7 that is radially closest to the impeller 1. It is arranged. The section B from the spiral start point 7 to the intermediate point 8 has a constant axial length F and maintains an appropriate clearance with the impeller 1. In the section C from the first intermediate point 8 to the second intermediate point 9, a first inclined surface 10 having a constant angle with respect to the casing side surface 4 is formed, and the axial length F increases in proportion to the rotation angle. In the section D from the intermediate point 9 to the spiral end point 11, the axial length F is constant,
The angle of inclination of the second inclined surface 12 increases so as to ensure a cross-sectional area equal to the axial length increasing in proportion to the angle of rotation. In the section E from the spiral end point 11 to the blowout intermediate point 13, the inclination angle of the third inclined surface 14 changes to become larger, and the cross-sectional shape at the blowout intermediate point 13 becomes rectangular. Further, in the section G up to the air outlet 6, the flow path is expanded at an appropriate enlargement angle while keeping the rectangular shape.

In the above configuration, when the impeller 1 rotates on the drive shaft 2, air is sucked into the impeller 1 through the nozzle 5 provided on the side surface 4 of the casing, is given energy within the casing, and is sent out to the outlet 6. At this time, the nozzle 5 is surrounded by a first inclined surface 10 and a second inclined surface 12, allowing air to flow in smoothly. Moreover, the air that has exited the impeller 1 is sent in a large amount due to the sufficient flow path area secured in the section C and the section D, and the air blowing performance is improved. Further, since the cross-sectional shape at the spiral end point 11 is close to a rectangle, the distance l of the section E that changes to a rectangular cross-section is short.

Effects of the Invention As is clear from the above embodiments, the centrifugal blower according to the present invention has a cross-sectional shape of the casing that has a section with a constant axial distance without an inclined part and an inclined part with a fixed inclination angle, and has a rotation angle. It has a section in which the axial distance increases proportionally, and a section having an inclined part, but the axial distance is constant and the inclination angle of the inclined part increases so as to increase the flow path area,
Compared to the conventional example, the axial distance and the length of the blowing part are small, ensuring a large flow path area, improving air blowing performance and reducing noise while reducing the size.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an example of a conventional centrifugal blower, FIG. 2 is a perspective view showing an example of the centrifugal blower of the present invention, and FIG. 3 is a plan sectional view taken along line X-X' in FIG. FIG. 4 is a front view of a centrifugal blower showing an example of the present invention. 1... Impeller, 3... Casing spiral surface, 4...
...Casing side surface, 5... Nozzle, 6... Air outlet, 7... Swirl starting point, 10... First inclined surface, 11
...Spiral end point, 12...Second slope, 14...Third slope.

Claims (1)

[Claims] 1 In a centrifugal blower having a multi-blade impeller, the shape of the spiral casing is such that the axial distance is constant along the rotational direction of the multi-blade impeller from the tongue portion whose radial distance is closest to the multi-blade impeller. A section, a section that has an inclined part and whose axial distance increases in proportion to the rotation angle, and a section that has a truncated rectangular cross section and whose axial distance is constant but the angle of the slanted part changes; A centrifugal blower consisting of three sections whose area increases in proportion to the rotation angle.