GB2103715A - Improved fan suction housing for vacuum cleaner - Google Patents

Abstract

A suction blower for a vacuum cleaner comprises an impeller 70 rotating within a shallow chamber 67 defined by two molded plastics members 29, 99. A plurality of diffuser vanes 110 molded integrally with the plastics member 29 are disposed in a circular array surrounding the edge of the impeller 70, there beings 6:1 ratio in the number of vanes 110 to impeller blades. The vanes 110 are disposed to direct airflow generally downstream with respect to the direction of rotation for the impeller and are constructed to reduce shock and diffusion losses and thereby achieve a smoother and more streamlined air flow. The impeller is driven by a motor 21,22 which is cooled by an auxiliary fan 55. <IMAGE>

Description

SPECIFICATION Improved fan suction housing for vacuum cleaner This invention relates generally to electric fans which produce suction for a vacuum cleaner and more particularly relates to an improvement over the structure disclosed in co-pending European Patent Application No. 81 105056.6 filed June 30th, 1981, entitled "FAN SUCTION FOR VACUUM CLEANER", and assigned to the assignee of the instant invention.

More particularly, the aforesaid co-pending application Serial No. 81105056.6 discloses a vertically disposed cylindrical tank having an electric fan with a pancake-type impeller axially disposed at the top of the tank for producing suction within the tank. Bearings for the output shaft of the fan motor are retained in portions of upper and lower housing sections. The lower housing section is molded of plastic material and cooperated with a molded plastic support member to define a shallow chamber wherein the fan impeller rotates. A relatively shallow slot in the annular wall of the chamber provides an exit for air flow generated by rotation of the impeller and the slot dimensions prevent accidental contact with the impeller. In order to protect the impeller the prior art has also provided formed metal housings with louvres or pierced openings.

In accordance with the instant invention, a plurality of vanes are positioned to form the outer boundary of the chamber wherein the impeller rotates. As will hereinafter be seen, these vanes are constructed and positioned so as to obtain smoother and more streamlined air flow by reducing shock and diffusion losses, thereby improving fan performance by increasing efficiency. These vanes are molded integrally with a plastic housing member which partially defines the impeller chamber.

The invention is directed to A blower device including first means defining a shallow chamber; a pancake-type impeller disposed within said chamber; an electric motor for rotating said impeller in a first direction about its central axis; a plurality of vanes within said chamber, positioned outboard of said impeller and spaced around the perimeter thereof; said impeller having a plurality of blades disposed to direct air radially outward of said impeller and through spaces between said vanes; said vanes extending upstream with respect to the direction of rotation for said impeller and slanting radially inward.

Figure 1 is a longitudinal cross-section of a suction producing unit constructed in accordance with teachings of the instant invention.

Figure 2 is an electrical schematic for the motor portion of Figure 1.

Figure 3 is a rear or top plan view of the lower housing section. Caps for the electrical brush support parts of the lower housing are also shown in Figure 3.

Figure 4 is a fragmentary side elevation of the lower housing looking in the direction of arrows 4-4 of Figure 3.

Figure 5 is a bottom or front elevation of the lower housing, looking in the direction of arrows 5-5 of Figure 4.

Figure 6 is a front elevation of the motor mounting member.

Figure 7 is a side elevation of the impeller.

Figure 8 is a front elevation of the impeller.

Figure 9 is a cross-section taken through line 9-9 of Figure 7 looking in the direction of arrows 9-9.

Figure 10 is a front elevation of the lower housing as in Figure 5, with the addition of the impeller.

Now referring to the Figures. Suction producing unit 20 of Figure 1 includes an electric motor comprising rotatable armature 21 surrounded by stator field piece 22. In a manner well known to the art, although not illustrated in the drawings, stator windings 23, 24 (Figure 2) are magnetically coupled with pole piece 22. The axis of rotation for armature 21 is defined by vertical shaft 25 which extends beyond both ends of armature 21 and is rotatably supported by upper and lower bearings 26, 27 respectively. Magnetic frame or field piece 22 is sandwiched between upper and lower housing sections 28. 29 which are connected by two screws 31 which extend vertically downward through clearance apertures in frame 22.

As explained in detail in the aforesaid application Ser. No. 81105056.6, upper housing section 28 is an inverted U-shaped member having vertical legs 32, 33 which extend downward from opposite ends of web 34. The free ends of legs 32, 33 are provided with respective out-turned ears 38, 39 having the clearance apertures through which screws 31 extend. The outboard end of ear 38 is provided with another aperture 41 to receive a grounding screw (not shown). The underside of web 34 is provided with concave seating surface 42 which is engaged by upper bearing 26. The periphery of ring-like spring retainer 43 is seated on a shoulder at the underside of web 34 and is secured to upper housing 28 by peening over portion 47 of web 34.

Spring member 43 is provided with upwardly facing concave seating surface 44 which is in engagement with upper bearing 26. Spring 43 biases upper bearing 26 upward against seating surface 42, and seating surfaces 42, 44 permit upper bearing 26 to swivel as required. This enables bearing 26 to rotatably support the upper end of shaft 25 which extends into an axial aperture of bearing 26.

Inverted cup-like cap 50 is secured to upper housing 28 by two screws 49 which are received in threaded engagement in apertures 48 in web 34 after passing through clearance apertures in the disk-like upper surface 52 of cap 50. Surface 52 is also provided with a plurality of ventilating openings (not shown) through which air is drawn downward by fan blade 55 which is disposed within cap 50 and is secured to the upper end of shaft 25 just below the upper bearing 26. Sleeve 54 on the upper end of shaft 25 operatively positions blade 55. Air moved by the latter serves to cool motor 21,22.

As seen best with reference to Figures 3 and 4, lower housing 29 is a molded insulating member formed with main cylindrical portion 61 concentric with motor shaft 25. Flange 62, which extends radially inward from the lower end of main section 61, is provided with central opening 63 through which the lower end of shaft 25 extends.

Surrounding opening 63 is upwardly extending lip 64 which positions lower bearing 27. The latter is a ball bearing unit whose inner race is closely fitted with respect to shaft 25. Corrugated tolerance ring 65 is interposed between lip 64 and the outer race of bearing 27. Flange 62 and flange 66, the latter extending radially outward from main section 61, form the upper plate-like boundary for shallow cavity or chamber 67 wherein suction fan impeller 70 is disposed.

Lower housing 29 also includes post formations 71, 71 adjacent the inner surface of main section 61. Posts 71 are provided with recesses 72 open at their upper ends to threadably receive screws 31.

Brush supports 73, 73 are formed integrally with and extend radially through main section 61.

Each support 73 is of generally rectangular crosssection having a through passage 76 which receives brass holder 74 for carbon brush 75. The latter is biased into engagement with commutator 77 mounted on shaft 25 and electrically connected to the windings of armature 21. Brass holders 74 are electrically connected to field windings 23, 24. A coiled compression spring (not shown) disposed within holder 74 biases brush 75 radially inward into good electrical contact with commutator 77. The outer end of passage 76 is closed by inwardly bending tabs (not shown) on opposite sides of brass holder 74. Plastic cap 78 covers the outer end of support 73, being removably held in operative position by four snapfitted fingers 79.Below and sideways of brush supports 73 main cylindrical section 61 is provided with apertures 81 which provide outlets for air moved radially by upper fan blade 55 to cool motor 21,22.

The end of field winding 23 remote from brush 75 is connected to electrical lead 151 (Figure 2) and the end of field winding 24 remote from the other brush 75 is connected to electrical lead 152.

Leads 151,152 extend radially outward of lower housing 29 through notch 153 (Figure 3) in the upper edge of main section 61, and are maintained at the bottom of notch 153 by a molded plastic clamping member (not shown) which is locked in position from above by field piece 22. Sponge-like ring 200 cemented to the upper surface of flange 66 provides a gasket for a cover (not shown) placed over motor 21, 22.

Extending downward from flange 66 are three posts 82 whose free lower ends are received by individual recesses 84 in the upper surface of plate-like motor support section 83 of molded plastic member 99. Support section 83 provides the lower boundary for shallow chamber 67.

Screws (not shown) extend upward through clearance apertures in support 83 and are received in apertures 86 of posts 82 to mechanically secure lower housing 29 to support 83. Support 83 is also provided with upwardly extending very short annular lip 85 positioned slightly outboard of impeller lower wall 105 to limit air flow leakage to the front of (below) impeller 70. Support 83 is provided with central opening 88 surrounded by downwardly extending cylindrical section 91. Cylinder 91 serves to axially direct air being drawn into fan impeller 70.

The latter is secured to shaft 25 which extends downward through central aperture 98 (Figure 9) in disk-like upper wall 95 of impeller 70. That is, the threads of flanged nut 92 are engaged with the threads at the lower end of shaft 25. Flanged spacer 93 on shaft 25 is interposed between impeller wall 95 and the inner race of bearing 27 on shaft 25. Wall section 95 of fan 70 is clamped between flanged spacer 93 and lower washer 96 as nut 92 is tightened against the latter. In a manner well known to the art, motor support 99 is mounted to the top of the vacuum tank 97 shown in phantom in Figure 1, and annular gasket 200 is cemented to the upper surface of flange 66 to support an optional removable protective cover (not shown) for motor 21, 22.

As seen best in Figures 7, 8 and 9, impeller 70 includes six curved blades 102 disposed edgewise and clamped between upper and lower circular parallel plate walls 95, 105. Lower wall 105 is provided with relatively large central air intake aperture 106. Blades 102 are disposed with their convex surfaces facing downstream with respect to the impeller direction of rotation indicated by arrow A in Figures 8, 9 and 10.

Molded integrally with lower housing 29 and extending below outer flange 66 are a plurality of vanes 110 whose lower ends rest against the upper surface of support 83. Typically, there are from two to ten vanes for each impeller blade. In the embodiment illustrated, there are six vanes 110 for each impeller blade 102. Vanes 110 extend close to and are equally spaced around the circular edge of impeller 70 to direct exhaust air flow, indicated by arrows B in Figure 10, while reducing turbulence.

Each vane 110 is inclined so that the downstream end thereof is radially outboard of the upstream end of vane 110. With the exception of those vanes extending inboard from the three posts 82, each vane 110 is constructed with inboard and outboard surfaces 111, 112. In crosssection, the major portion 11 3 of outboard surface 112, extending to the downstream end thereof, is parallel to inboard surface 111 and the other portion 114 of surface 112, at the upstream end thereof, is inclined with respect to surface 111, being closest thereto at the upstream end of surface 111. Positioning of vanes 110 is such that between the upstream end of one vane 110 and the downstream end of the adjacent upstream vane 110 there is a clearance space through which a true radial line 115 (Figure 10) may be drawn to a point outboard of vanes 110 without intersecting any of the vanes 110.

Although the present invention has been described in connection with a preferred embodiment thereof, many variations and modifications will now become apparent to those skilled in the art. It is preferred, therefore, that the present invention be limited not by the specific disclosure herein, but only by the appended

Claims (11)

claims. CLAIMS

1. A blower device including first means defining a shallow chamber; a pancake-type impeller disposed within said chamber; an electric motor for rotating said impeller in a first direction about its central axis; a plurality of vanes within said chamber, positioned outboard of said impeller and spaced around the perimeter thereof; said impeller having a plurality of blades disposed to direct air radially outward of said impeller and through spaces between said vanes; said vanes extending upstream with respect to the direction of rotation for said impeller and slanting radially inward.

2. A blower device as set forth in Claim 1 in which the vanes are positioned so that between the inboard end of each vane and the outboard end of the adjacent upstream vane there is a narrow space which provides a clear true radial path from said impeller outboard of said vanes.

3. A blower device as set forth in Claim 1 in which each of the vanes includes a tapered section that is narrowest at the inboard end of the vane.

4. A blower device as set forth in Claim 3 in which each of the vanes includes a first flat surface that extends substantially the entire distance between the inboard and outboard ends of the vane.

5. A blower device as set forth in Claim 4 in which each of the vanes includes a second surface opposite said first surface; a portion of said second surface extending from the inboard end thereof only partway toward the outboard end thereof; said portion being slanted with respect to said first surface and being closest thereto at the inboard end of the second surface.

6. A blower device as set forth in Claim 1 in which the impeller includes a plurality of angularly spaced blades, there being generally in the range of two to ten of said vanes for each of said blades.

7. A blower device as set forth in Claim 6 in which the impeller includes a plurality of angularly spaced blades; each of said blades having its outboard end positioned upstream of its inboard end; each of said blades being curved end to end with its downstream facing surface being convex.

8. A blower device as set forth in Claims 6 or 7 in which there are approximately six of said vanes for each of said blades.

9. A blower device as set forth in Claim 1 in which the impeller is disposed between front and rear generally parallel confronting surfaces in planes positioned perpendicular to said central axis and defined by said first means; said impeller including front and rear circular plates, and a plurality of blades disposed between said plates; an annular lip extending from said front surface slightly to the rear of said front plate in close proximity thereto and operatively shaped to limit leakage to the front of the impeller.

10. A blower device as set forth in Claim 1 in which said first means includes first and second members having respective first and second generally parallel confronting surfaces in planes positioned perpendicular to said central axis and having said impeller disposed therebetween; said first member being constructed of molded plastic material and having said vanes formed integrally therewith.

11. A blower device substantially as herein described with reference to, and as shown in, the accompanying drawings.