Wet pick-up vacuum unit motor bearing air seal

Abstract

A wet pick-up type vacuum motor fan unit with a separately ventilated motor section and a motor end bracket serving also as a support for, and part of a discharge end housing wall for, the working air fan section, has on the bracket fanward face a centrally apertured metal disk plate defining a flow space or path for bearing sealing air flow from ambient air inlets external of the motor section to a central discharge into the inlet eye of an auxiliary fan clamped on the shaft back-to-back with a larger diameter working air centrifugal fan adjacent the end bracket. A stamped shield cup jointly clamped on the shaft with the fans extends out of the auxiliary fan inlet eye into the disk central aperture, surrounding the shaft bearing socket of the bracket and being spaced from the disk aperture edge to afford a sealing air outlet from said space into the auxiliary fan inlet eye; whereby the disk plate and shield afford mechanical shielding, while air, discharging to and from the auxiliary fan, provides air shielding of the shaft and bearing area from working air entrained foam and moisture.

Description

27 25 thus lying at a location radially outward of band 20, hence effectively external of the motor housing structure.

The fan section F actually represents a two-stage design. The fan housing H conventionally includes shell structure fitted onto the exterior of the rim 12r, and here comprising two flat-bottomed cylindrical-walled drawn sheet metal shells 31 and 35. The shell portion 31, with its cylindrical wall fitted on the rim and surrounding the radially tapered second stage impeller 32, has a radial wall with a central opening as the inlet to the eye of the second stage impeller and having fixed on its outer or rightward face conventional stationary vanes 33. Thus the discharge periphery of impeller 32 is axially offset from the housing outlet therefor to discharge outwardly and then feed axially into the previously described channel 24.

For a first stage impeller 34 identical to impeller 32, the second shell portion 35 is telescoped onto a slightly reduced cylindrical end portion of 31, and in its basically flat-bottomed, i.e., radial wall region, has a large central inlet opening 36 for flow of working air axially to the first stage impeller inlet eye. A concentric annular inward beading 36b provides not only some structural rigidity for the end wall, but also a degree of pinching off the area between that housing front wall and the adjacent front end face of the impeller 34, to some degree to prevent recirculation from the impeller peripheral discharge area back to its inlet eye. Both the fans here are shown in a preferred radially tapering form now known to the art, comprising a main body disk centrally apertured for the shaft, an annular disk, and a series vane elements fixed therebetween.

Conventionally the first stage impeller 34 and second stage impeller 32 are secured on the rightwardly projecting end of the motor rotor shaft by means of a first axial spacer 37 including a sleeve portion about the shaft bearing against the inner race of ball bearing 16 and having a radial flange affording a clamping reaction surface for the main disk of fan 34; an elongated interstage spacer 38 between the impellers; an external washer 39 on the outer side of the first stage impeller body disk; and finally the clamping nut 40 threaded onto the shaft end.

The flow path of a working air from the inlet 36 of the housing H through the first stage impeller 34, the interstage "stationary fan" 33, the second stage working impeller 32, to the channel 24 leading to outlet 24a, is indicated by the solid arrows. The flow path of ventilating air for the motor is indicated by the dash-dotted direction arrows in the motor section.

Moreover, on the shaft T and between the flanged member 37 and the main disk of impeller 32, there are further clamped a "non-tapered" auxiliary fan 42 of appreciably smaller diameter than, and in back-to-back relation with, fan 32; and also a cup-shaped further baffle or shield element 43 centered in the eye of fan 42. It will be observed that the circumferential wall of shield member 43 has a fairly close running clearance about the rightwardly projecting bearing socket 18, and also extends axially through the central opening of the disk 27 towards flat fanward face 12f of end bracket 12. Thus the annular outlet, from the auxiliary air path or flow space defined between 27 and 12, in effect opens along the exterior surface of shield cup 43 into the eye of fan 42.

As indicated by the dotted arrow lines, the auxiliary air or bearing sealing air flows inwardly from the inlets 28, then axially past the bearing region into the eye of fan 42, and from the latter discharges, toward the main or working air outlet channel 24, through the space between the impeller 32 and the effective inner face of the fan housing, i.e., the disk plate 27. Thus a first obstacle to foam or detergent movement toward the bearing is provided by the auxiliary air discharging from fan 42; a second, by the flow of air through the outlet 27c around the shield 43 into the eye of fan 42; and a third and fourth, by the presence of the disk 27 forward of the face 12f in conjunction with the rotating cup shield both as extending in to the central aperture 27c and also as surrounding the bearing socket.

Claims

1. In a wet pick-up type vacuum cleaner fan unit with a cleaning working air centrifugal fan impeller mounted on a fan shaft supported in a lubricated bearing received in a central socket of a fan housing end wall,

said impeller peripherally discharging to a working air outlet of the housing located adjacent to said end wall,

the improvement comprising:

a centrally apertured disk plate circumferentially engaged and sealed upon and spaced from the fanward inner face of the said end wall;

a plurality of angularly spaced auxiliary or sealing air inlets through said wall from the exterior to an air flow space defined between the disk and end wall face;

an auxiliary centrifugal fan of smaller diameter than, and in back-to-back relation with, said working fan impeller,

said auxiliary fan being clamped on said shaft with its inlet eye facing the central aperture of said disk to receive auxiliary air therefrom;

a shield cup received with circumferential spacing in the auxiliary fan inlet eye and

having a centrally apertured flat bottom conjointly clamped with said fans on said shaft, and

extending through the central aperture of the disk to define with the edge thereof a discharge outlet from said flow space into the auxiliary fan eye;

whereby said shield and disk provide structural screening around said bearing socket and shaft, and

said auxiliary fan, shield and disk further moving auxiliary screening and sealing air axially exterior to the socket and on out to a common discharge of said back-to-back auxiliary and working air fans to prevent foam and working air entrained detergent from approaching said bearing.

2. A wet pick-up type vacuum cleaner fan unit improvement as described in claim 1, wherein

the bearing-receiving central socket projects from said end wall toward the adjacent but axially spaced working air fan; and said shield cup has its circumferential wall surrounding the socket projection with running clearance.

3. A wet pick-up type vacuum cleaner fan unit improvement as described in claim 2, wherein

said socket projects through the central aperture of said disk plate into the central inlet eye of the auxiliary fan.

4. A wet pick-up type vacuum cleaner fan unit improvement as described in claim 3, wherein

the inner face of said end wall is provided with a circular bead concentric with the shaft and located radially outward of said air inlets;

said disk having a cylindrical short rim flange fitted over said bead thereby to secure and seal the disk to said end wall.

5. A wet pick-up type vacuum cleaner fan unit improvement as described in claim 1, wherein

said end wall is an end bracket comprising part of a motor housing of an electric motor incorporated in said unit as a motor-fan unit; and

the motor housing is ventilated by a cooling air stream separate from the working air stream.

6. In a wet pick-up type vacuum cleaner fan unit in which the working air (by which cleaning is performed) is driven by a working air fan, said fan is mounted on a fan shaft journaled in a bearing supported by a fan housing end wall which extends transversely of said shaft, said fan discharging, through at least one outlet of the housing, the working air which is drawn by said fan through an inlet to said housing, the improvement comprising:

a baffle plate having a substantially central aperture through which said shaft extends into said housing, said plate being in a substantially peripheral engagement with the inner face of said end wall but elsewhere spaced therefrom in the direction of said working air fan to provide air flow space between said wall and plate;

at least one auxiliary sealing air inlet leading through said wall into said air flow space, any such auxiliary air inlet being spaced from said shaft and any such outlet;

an auxiliary fan mounted on said shaft between said working air fan and said baffle plate, said fan having its inlet eye facing the aperture of said baffle plate to receive sealing air therefrom; and

means having an outer surface substantially concentric with said shaft and which is partly located within, but radially inwardly spaced from, the eye of said auxiliary fan, said means and said fans being mounted on said shaft for rotation therewith, said means extending axially from said auxiliary fan through the aperture of said baffle plate at least as fan as said bearing, the surface of said means where it passes through the aperture of said baffle plate being peripherally spaced therefrom to provide a substantially annular opening for auxiliary sealing air entering and flowing in said air flow space toward said shaft in order to pass axially through said annular opening into the auxiliary fan eye and thence radially outwardly to a common discharge of air from said auxiliary and working air fans, such passage of sealing air axially through said annular opening thereby inhibiting the approach to said bearing of foam and liquid entrained in said working air. 7. A wet pick-up type vacuum cleaner fan unit improvement as defined in claim 6, wherein said bearing support projects inwardly from said end wall toward, but is axially spaced from, the said working air fan; said means having an outer surface substantially concentric with said shaft is a shield cup; and the rim of said shield cup surrounds the projection of the bearing support and extends to the inner face of said end wall with a running clearance. 8. A wet pick-up type vacuum cleaner fan unit improvement as defined in claim 7, wherein said bearing support projects through the aperture of said baffle plate and at least partly into the central inlet

eye of the auxiliary fan. 9. A wet pick-up type vacuum cleaner fan unit improvement as defined in claim 8, wherein the inner face of said end wall is provided with a peripheral projection which is substantially concentric with the shaft and located, with respect to said shaft, outwardly of said air inlets; said baffle plate has a rim flange fitted over said projection thereby to secure and seal the baffle plate to said end wall. 10. A wet pick-up type vacuum cleaner fan unit improvement as defined in claim 6, wherein said fan housing end wall is also the end bracket of a separate housing for an electric motor having an armature shaft which is extended through said bearing to serve as the said fan shaft and any auxiliary sealing air inlet is located exteriorly of the balance of the portion of the unit which serves as the said housing for said motor, said motor housing having openings therein for the inlet and outlet of air for cooling said motor, whereby the motor-cooling air stream is separate from the working and cooling air streams.

11. In a wet pick-up type vacuum cleaner fan unit comprising a motor, means for moving cooling air past said motor, a housing for said motor, said motor housing having at least one inlet and at least one outlet for said motor cooling air, a fan housing, an end wall for said fan housing segregating said fan housing from said motor, motor housing, and any inlet or outlet thereof for motor-cooling air, a rotatable fan shaft extending through said end wall into said fan housing, a bearing which is supported in said end wall and in which said shaft is journaled, said shaft rotatingly connected to said motor, said fan housing having at least one inlet and one outlet for working air by which cleaning is performed, the improvement comprising:

at least one auxiliary sealing air inlet extending through said wall, such auxiliary air inlet being spaced from said shaft and any outlet for working air,

baffle plate means mounted on the side of said wall within said fan housing and having an aperture through which said shaft extends as it enters said housing, said baffle plate means extending from any auxiliary air inlet to a position adjacent said shaft to define an air flow space extending from any said auxiliary air inlet to and around said shaft, the periphery of said shaft and any means mounted thereon which also extends through and is spaced from said aperture defining, when said shaft is rotated, the inner periphery of an annular opening from said air flow space into said housing and the periphery of said aperture defining the outer periphery of said annular opening, and

fan means mounted on said shaft, forcing said working air through said fan housing, and presenting toward said annular opening a fan eye whereby, when said shaft is rotated, auxiliary sealing air is drawn through said auxiliary air inlet, air flow space, and axially through said annular opening into said fan eye for discharge with the working air through a working air outlet of said housing, whereby passage of auxiliary air through said annular opening inhibits the approach to said bearing, during rotation of said shaft, of foam or liquid entrained in said working air, and wherein said auxiliary sealing air is exclusive of any cooling air moving past said motor.