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.

What we claim is: 
     
       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. .Iadd.   
     
     
       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. .Iaddend. .Iadd.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. .Iaddend. .Iadd.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. .Iaddend. .Iadd.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. .Iaddend. .Iadd.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. .Iaddend. 
     
     
        .Iadd.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. .Iaddend.