Bearing retainer structure

An improved bearing retainer structure having a hub supporting an annular bearing in which a shaft can be journaled, a preselected space being provided between the outer periphery of the bearing and the inner wall of the hub to receive an expansible-compressible fastening device which retains the bearing in position to enhance the resistance to torsional, axial and radial thrusts.

BACKGROUND OF THE INVENTION 
This invention relates to an improved bearing retainer structure and more 
particularly to an improved endshield assembly structure for an electric 
motor including a novel bearing retainer arrangement and a tool for 
mounting the same. 
It is known in the prior art to support an annular bearing in the hub 
portion of an endshield of an electric motor, the inner periphery of the 
bearing having the rotor shaft of the electric motor journaled therein. 
Various arrangements have been utilized to hold or retain the bearing in 
position in the hub portion including a more recent and now common 
arrangement of rolling or coining the inner edge of the hub to lap over an 
outer bearing face to retain and secure the bearing in position. This 
arrangement, however, as recognized by the present invention, has required 
comparatively complex and expensive assembly and machining steps, has 
placed undesirable stresses on both the endshield and bearing race, has 
led to the presence of undesirable particulate matter brought about by the 
rolling or coining operations and has prevented the repair and reuse of 
the completed assembly. 
The present invention, recognizing these aforementioned limitations of past 
bearing retainer structures, provides a bearing retainer arrangement and 
an assembling tool therefor which are straightforward and economical in 
both manufacture and assembly, which serve to efficiently retain the 
bearing, torsionally, axially and radially, without requiring refined 
machining operations on the inner wall of the hub portion, and without the 
presence of undesirable machining particulate matter and undesirable 
bearing stresses and distortions and which, at the same, allow for rapid 
and economical assembly and disassembly for reuse of the major portion of 
the several parts involved in the assembly. 
Various other features of the present invention will become obvious to one 
skilled in the art upon reading the disclosure set forth herein. 
SUMMARY OF THE INVENTION 
More particularly, the present invention provides an improved bearing 
retainer structure particularly adaptable to an endshield for an electric 
motor comprising: a bearing hub having support means to support a bearing 
thereon; an annular bearing mounted in the bearing hub with one face 
thereof resting on the support means of the hub to allow a shaft to be 
journaled therein, the bearing and hub being relatively sized to provide a 
preselected space therebetween to eliminate the need for machining 
operations; and, fastening means adapted to be inserted into press-fit 
relation in the space between hub and bearing to firmly retain the bearing 
in position to absorb torsional, axial and radial thrusts of the journaled 
shaft. In addition, the present invention provides a novel structure for 
centering the bearing in the hub and for applying a retaining pressure on 
the bearing at a preselected area on the bearing. Further, the present 
invention provides a novel tool assembly to press-fit the fastening means 
into desirable bearing retaining position. 
It is to be understood that various changes can be made by one skilled in 
the art in the arrangement, form and construction of one or more of the 
several parts of the inventive structure disclosed herein without 
departing from the scope or spirit of the present invention. For example, 
the type and shape of the bearing retaining means and the assembly tool 
therefore can be modified without departing from the present invention.

DETAILED DESCRIPTION OF THE DRAWINGS 
As can be seen in FIGS. 1 and 2 of the drawings, the endshield 2 which can 
be any one of several types of upper or even lower endshields known in the 
art for assembly to extending corner sections of a stator of an electric 
motor (not shown) by suitable fasteners (also not shown) which pass 
through apertures 3, the apertures 4 in mounting bosses 6 serving to 
receive mounting bolts (not shown) for mounting the electric motor to the 
apparatus with which the motor is to be associated, for example the sump 
of a dishwasher. 
Advantageously, endshield 2 can be formed from an appropriately cast 
aluminum material with centrally disposed ventilation slots 7 separated by 
integral ribs 8 which serve to support hub or cradle 9 having an opening 
11 therein into which a rotor shaft of an electric motor can be extended. 
As can be more fully seen in FIGS. 2 and 3 of the drawings, hub 9 is 
truncated with the sides thereof sloping inwardly toward the motor (not 
shown) on which the endshield 2 is to be mounted. The lower end of hub 9 
is turned inwardly to provide a bearing support means in the form of an 
annular support lip 12 to receive and support the outer race 13 of annular 
ball bearing member 14. The inner race 16 serves to receive an electric 
motor shaft which is to be journaled therein. 
It is to be noted that the outer race 13 is provided with a curvilinear 
corner surface at 17 to nest with a curvilinear corner 18 formed by 
inwardly projecting support lip 12 to thus permit ready centering of the 
annular bearing member 14. It is to be further noted that the outer 
periphery of annular bearing member 14 and surrounding hub 9 are 
relatively sized to provide an annular space 19 between the outer 
periphery of the outer race 13 of annular bearing 14 and the surrounding 
inner wall of hub 9. This arrangement of providing the annular space 19 
between the inner wall of the hub and the outer periphery of the bearing 
eliminates the need for inner wall machining, the annular space 19 as 
shown being of tapered cross-section, narrowing toward the support lip 12 
of hub 9. 
Annular tapered space 19 between the hub and outer periphery of the bearing 
serves to receive the perimeter portion of an annular fastening member 21. 
The perimeter portion of fastening member 21, which is herein broadly 
designated by reference numeral 22, is of U-shaped cross-section with an 
integral downturned leg 23 and a substantially parallel spaced upturned 
leg 24, joined at the lower portion by curved integral corner surface 26 
to provide an annular expansible-compressible ring adapted to be press-fit 
into the tapered space between the outer periphery of bearing member 14 
and inner wall of hub 9. It is to be noted that upturned leg 24 has the 
free end thereof terminating in an outwardly turned lip 27, the lip 27 
being so sized that the edge engages tightly with the inner wall 25 of hub 
9 to enhance the resistance to torsional, axial and radial thrusts and to 
serve as a guide to center the fastening member during assembly, the 
curved integral corner surface 26 completing the centering of the bearing 
14 started by nesting curvilinear corners 17 and 18 as abovedescribed. The 
surface of this inner wall 25 of hub 9 can be so selectively contoured as 
to provide a cam action with the tightly contacting edge of outwardly 
turned lip 27 to cause downturned leg 23 to bear against the outer 
periphery of the bearing member along a preselected area between or 
intermediate the opposed faces of the bearing member 14 when the 
expansible-compressible perimeter portion 22 is inserted into tapered 
annular space 19. 
Fastening member 21 further includes a flat annular bearing face gripping 
portion 28 which extends from the upper part of downturned leg 23 opposite 
the outwardly turned lip 27 to engage the face of bearing member 14 
opposite the face of the bearing member which rests on inwardly extending 
support lip 12 when fastening member 21 is press-fit into position. 
To provide for efficient and accurate press-fit engagement of fastening 
member 21, an assembling pressure tool 29 (FIG. 4) can be provided. Tool 
29 is sized to cooperate with fastening member 21, bearing member 14 and 
hub 9 and includes a cylindrical pilot member 31 centrally disposed in an 
anvil member 32 which is slidably mounted thereon. Pilot member 31 is 
sized to nest with the inner race 16 of bearing member 14 and anvil member 
32 is provided with an annular striking base 33 sized to engage against 
bearing face gripping portion 28 of fastening member 21 to permit said 
anvil 32 to urge the fastening member 21 into press-fit relation in 
tapered annular space 19 to thus secure the bearing member 14 from 
torsional, axial and radial thrusts. It is to be noted that anvil 32 is 
provided with a chamfered peripheral edge 34 extending from striking base 
33, edge 34 being sized and contoured to engage against outwardly turned 
lip 27, advantageously at an approximate 45.degree. angle, so that during 
pressfit operations lip 27 follows the taper of inner wall of hub 9 to 
provide the aforedescribed cam action. It is further to be noted that 
pilot member 31 can be provided with a suitable stop washer 36 to limit 
sliding movement of anvil 32 thereon. 
It is to be understood that various changes can be made by one skilled in 
the art in the apparatus abovedescribed without departing from the scope 
or spirit of this invention. For example, it would be possible to change 
the contour of the inner wall of the hub so that the relative spacing 
between it and the outer periphery of the bearing would have a different 
geometry from that disclosed. It also would be possible to mount other 
types of bearings different from the annular bearing disclosed to support 
a rotor shaft.