Bearing servicing tool

A tool for removing and/or replacing bearings in situ comprises a brace having a first end adapted to engage a first end of the bearing housing, and a second end adapted to engage a second end of the bearing housing. If the two ends of the bearing housing are different in configuration, the respective ends of the brace are correspondingly configured. An elongate guide member integral with the brace has two parts, each projecting endwise from a respective end of the brace. A pressure plate is alternatively removable mountable on either part of the guide member for longitudinal movement therealong, and has first and second ends of different configurations adapted to engage first and second ends respectively of the bearing. A threaded-type drive is cooperative between the guide and the pressure plate to move the pressure plate longitudinally along the guide and apply a force to the bearing, either to remove the bearing from its housing, or to emplace a new bearing in the housing.

ORIGIN OF THE INVENTION 
The invention described herein was made by an employee of the United States 
government and may be manufactured and used by and for the government of 
the United States of America for governmental purposes without the payment 
of any royalties thereon or therefor. 
BACKGROUND OF THE INVENTION 
The present invention pertains to the servicing of rotary bearings, and 
more particularly to the removal of rotary bearings in which the outer 
race is press fit into a generally annular housing and/or to 
re-emplacement of a new bearing into such housing. Such servicing may be 
particularly difficult and time consuming if it is necessary, and also 
difficult, to remove the bearing housing from the apparatus in which it is 
normally employed and send that housing to a shop or the like. An example 
of a particularly difficult environment is in the horizontal tail control 
system of certain aircraft. An exemplary set of instructions for removing 
the bearing housing from such an aircraft portion comprises some nine 
pages of instructions and illustrations, and in practice, takes several 
hours to perform; this is before the actual process of removing the old 
bearing from the housing can even begin. 
Furthermore, apparatus typically used for the actual bearing removal 
process is often expensive, bulky and/or dangerous, e.g. hydraulic or 
pneumatic equipment. 
A number of prior art devices have been developed for attempting to provide 
smaller, simpler tools for removing bearings from their housing, and at 
least some of which might be used with the housing in situ in the 
apparatus, typically an automotive vehicle. These typically utilize a 
stationary member for taking purchase against the bearing housing and a 
movable member for pushing against the bearing proper, the members being 
interconnected by some type of screw thread drive. However, these have 
suffered from a variety of disadvantages. 
U.S. Pat. No. 3,393,441 to Gebhart discloses a device which is only usable 
for forming or breaking a press fit of an inner bearing race with respect 
to a shaft. Furthermore, it utilizes a number of different separable 
parts, and different combinations of these parts must be used depending 
upon whether the apparatus is being used to emplace a new bearing or 
remove an old bearing. These parts can be lost or mislaid, and the manner 
of assembly for the different functions of the tools is relatively 
complicated. 
U.S. Pat. No. 2,287,767 discloses a device which is only for emplacing a 
pair of axially spaced bearings, and which is designed to apply pressure 
only to the inner races of those bearings. The device cannot be used to 
remove bearings. 
U.S. Pat. No. 4,437,220 to Gregory is specialized for use in a particular 
type of universal joint, and while fairly simple in and of itself, 
actually makes use of certain parts of the universal joint, so that it is 
not applicable to rotary bearings in general. 
U.S. Pat. No. 4,624,040 to Sabo is even more complicated, in terms of the 
number of different parts, than the aforementioned patent to Gebhart, not 
only requiring different parts for removing and emplacing bearings, but 
also having further parts for removing and emplacing wheel hubs. The 
chance of dissemination of the parts and/or confusion by the operator is 
therefore increased. 
U.S. Pat. No. 4,542,571 to Sullivan discloses a fairly simple device 
wherein the same parts, if rearranged, can be used for either emplacing or 
removing bearings. However, this device is not readily applicable to the 
types of bearings described above in connection with aircraft, wherein the 
opposite ends of the bearing housing are different in configuration, and 
wherein it is undesirable to apply pressure to both the inner and outer 
bearing races when pressing a new bearing into its housing. 
SUMMARY OF THE INVENTION 
The present invention addresses the above problems by providing a tool 
which can be used in situ either for removing or emplacing bearings, even 
bearings such as those of aircraft, which may have asymmetrical housings. 
Nevertheless, the tool is fairly simple, both in construction and 
operation, and includes relatively few separate parts. Furthermore, those 
few parts, when not in use, can be connected together in a simple manner 
which will prevent their dissemination or loss. 
More specifically, apparatus in accord with one preferred embodiment of the 
invention comprises a bracing body having first and second ends adapted to 
engage first and second ends, respectively, of a bearing housing, in the 
alternative; that is to say, the first end of the bracing body may engage 
a first end of the bearing housing for bearing removal operation, and the 
bracing body can be repositioned so that its second end engages the second 
end of the bearing housing for use in installing a new bearing in the 
housing. An elongate guide member has first and second parts projecting 
endwise from the first and second ends, respectively, of the bracing body. 
A motive body is removably mountable on either of the two parts of the 
guide member, in the alternative, for longitudinal movement therealong. 
The motive body has first and second ends of different configurations 
adapted to engage first and second ends, respectively, of a bearing in, or 
to be emplaced within, the bearing housing. A force transmission means is 
cooperative between the guide member and the motive body to move the 
motive body longitudinally along the guide member and apply a force to the 
bearing. 
Thus, in a bearing removal mode, after the central shaft which is normally 
supported by the bearing has been removed, but with the bearing housing 
still in situ, the first end of the bracing body can be placed in 
engagement with the first end of the bearing housing, with the first part 
of the guide member extending centrally through the bearing along its 
axis. The motive body is then installed on the first part of the guide 
member, with its first end facing the bearing, that first end being sized 
to fit within the adjacent (second) end of the bearing housing and to abut 
the bearing, preferably including abutment of the outer race of the 
bearing. The force transmission means, which may include threads on the 
guide member and on a drive nut emplaced on the drive member outwardly of 
the motive body, may then be used to move the motive body inwardly on the 
guide member, thereby forcing the bearing out of its housing. 
In a bearing installation mode, the second end of the bracing body is 
placed in engagement with the second end of the bearing housing, with the 
second part of the guide member extending centrally through the bearing. A 
new bearing is placed on the second end of the motive body, which is 
preferably adapted, by the provision of portions of different outer 
diameter, to carry the bearing. This subassembly is then placed on the 
guide member with the bearing and the second end of the motive body facing 
toward the bearing housing. The drive nut is once again emplaced on the 
guide member outwardly of the motive body and used to move that body 
inwardly on the guide member, thereby forcing the bearing carried thereby 
into its housing. Preferably, the second end of the motive body has an 
axial recess which clears the inner race of the bearing, so that the 
pressing force is applied only to the outer race of the bearing during the 
installation process. 
The invention contemplates a number of other salient features which, in 
various embodiments of the invention, can be combined with the above 
features or used independently. 
More particularly, the two ends of the bracing body may be of differing 
configurations so as to accommodate an asymmetrical bearing housing such 
as is often found in aircraft. Even more specifically, the first end of 
the bearing housing may have an annular axially outer surface which is 
inclined with respect to the bearing axis. The first end of the bracing 
body may be correspondingly inclined, and indicia marks may be provided on 
the bearing housing and the bracing body to aid in properly "mating" those 
inclined surfaces, i.e. abutting them in complementary relationship. The 
second ends of the bearing housing and bracing body may be of different 
configuration or orientation, e.g. perpendicular to the axis of the 
bearing and the tool (which are collinear in use). 
Another such salient feature is that the guide member may be integrated 
with the bracing body, so as to reduce the number of separable parts, and 
thus the chances for dissemination and/or loss of parts of the apparatus. 
Still other salient features of the invention, as well as various objects 
and advantages thereof, will be made apparent by the following detailed 
description, claims, and the drawings, wherein:

DETAILED DESCRIPTION OF THE INVENTION 
An exemplary embodiment of the invention is illustrated in conjunction with 
a bearing of a type used in the horizontal tail control system of an 
aircraft, and the illustrated embodiment is particularly adapted for use 
with this type of bearing. It will be appreciated that the configuration 
of certain parts of the tool apparatus could be modified for use with 
bearings having different configurations, within the spirit of the present 
invention. 
The bearing assembly includes an annular bearing housing 10 having the 
annular bearing proper 12 concentrically mounted therein. The bearing 
housing 10 has a first end with an annular axially outwardly facing 
surface 14 which is inclined with respect to the central axis of the 
bearing, as best seen in FIGS. 2 and 4. The other or second end of the 
bearing housing has an annular axially outer surface 16 which lies 
perpendicular to the bearing axis. Adjacent surface 16, the housing 10 
includes a pair of diametrically opposed ears 18 which project radially 
into the interior of the bearing housing at its second end; ears 18 do not 
extend the full length of the bearing housing 10. The housing 10 has a 
relatively large inner diameter, as indicated at 20, at its first end, and 
a smaller inner diameter 22 at its second end, a shoulder 24 facing 
axially toward the first end thus being formed at the juncture between the 
large and small inner diameter parts 20 and 22. A base portion 26 is 
integrally formed on the housing 10 and extends radially outwardly 
therefrom, more specifically downwardly in use, as shown. A trunion-like 
pin 28 integral with and extending further outwardly from base 26 is 
adapted for disposition in a bore of a bearing support member 30 in the 
aircraft. 
The bearing proper includes an outer race 32 press fitted into the large 
diameter part 20 of the housing 10 and in abutment with the shoulder 24, 
an inner race 34, which, in use, engages and rotates with a shaft (not 
shown) supported by the bearing 12. The races 32 and 34 are spaced apart, 
and have opposed surfaces configured to capture a set of anti-friction 
elements, in this case balls 36, which complete the bearing subassembly 
12. 
To prepare the bearing assembly 10, 12 for servicing, the shaft has been 
removed leaving the interior of the bearing free and open, but the bearing 
housing 10 has been left in situ on its support 30 in the aircraft. FIGS. 
1-3 show how a tool in accord with the present invention is then applied 
to the bearing assembly for removal of the bearing proper 12. 
The tool includes a bracing body 38 which is generally cylindrical, having 
a first, open end terminating in the annular axially outer surface 40 
which is inclined at a corresponding angle to surface 14 of bearing 
housing 10. The second end of the bracing body 38 is closed by an end wall 
42 whose axially outer face 44 lies perpendicular to the axis of the 
cylindrical bracing body 38. Surfaces 40 and 44 could be configured in any 
suitable manner so as to properly engage surfaces such as 14 and 16, but 
of bearing housings of different configurations. It is noted that, when it 
is said that the surfaces 40 and 44 engage respective surfaces 14 and 16, 
it is meant that such engagement occurs in the alternative, depending upon 
whether the tool is assembled for bearing removal (FIG. 2) or bearing 
emplacement (FIG. 4). 
The tool of the invention further includes an elongate guide member in the 
form of a large threaded pin having first and second parts 46a and 46b, 
respectively. Pin 46a, 46b, in the embodiment shown, is formed 
monolithically with end-wall 42 of bracing body 38. However, in other 
embodiments, it is possible to form the pin 46a, 46b separately, and place 
it in a suitable hole in end wall 42, and then integrate it with wall 42 
by welding, or removably secure it to wall 42, as by suitable grooves and 
snap rings or the like. In any event, it is preferred that the pin 46a, 
46b either be integral with body 38 or connected thereto by secure means 
which minimize the chance of separation of the pin from the bracing body 
and dissemination of these parts of the apparatus. 
In any case, first part 46a of the pin extends through the interior of body 
38 toward and beyond its first end surface 40, whereas the second part 46b 
extends from and beyond the second end surface 44, both coaxially with the 
cylindrical bracing body 38. Each of the pin parts 46a and 46b has its 
outermost portion externally threaded. 
The tool further includes a motive body 48 having generally circular 
exterior surfaces and a central aperture 50 sized for sliding receipt of 
either first part 46a or second part 46b of the guide member. The motive 
body 50 has a first end including a continuous annular face 52 lying 
perpendicular to its axis and a peripheral surface 54 which, but for the 
interruption provided by slots 56, which are sized to receive and bypass 
housing ears 18, is cylindrical and sized for a sliding fit in relatively 
small inner diameter part 22 of the bearing housing 10. 
The second end of the motive body 48 has a different configuration from 
that of its first end, for reasons to be developed below. The second end 
includes an axially outermost, relatively small outer diameter part 55 
sized for sliding receipt in inner race 34 of the bearing 12 and having a 
continuous, annular, axially outer face 56. Axially set back from face 56, 
the second end of the motive body 48 also includes a relatively large 
outer diameter part 58 sized for a sliding fit in the relatively large 
inner diameter part 20 of the bearing housing 10. An external axially 
facing shoulder 60 is formed at the juncture of large diameter part 58 of 
the second end and intermediate diameter part 54 of the first end of the 
motive body. Another shoulder, 62, facing in the opposite axial direction, 
is formed at the juncture of the two parts 55 and 58 of the second end of 
the motive body. This shoulder 62 has an annular axial recess 64 adjacent 
small diameter part 54. 
The third and final part of the tool illustrated is a drive nut 66 adapted 
to be threaded onto either of the pin parts 46a or 46b, in the 
alternative. 
To remove the bearing 12 from its housing 10, the respective first ends of 
the bracing body 38 and bearing housing 10 are engaged by abutting their 
surfaces 40 and 14, as shown in FIGS. 2 and 3. To be sure that the 
inclined surfaces 40 and 14 "mate," i.e. that they are arranged in 
complementary manner so that pin 46a, 46b lies along the axis of the 
bearing, indicia marks 68 and 70 are provided on the outside of the 
housing 10 and body 38, as shown in FIG. 3, and are visually aligned. It 
will be seen that, with surfaces 14 and 40 properly abutting, first part 
46a of the guide pin extends through the bearing housing 10 and projects 
out the other side. 
Motive body 48 is emplaced on first part 46a of the guide pin with its 
first end 54 innermost. For convenience, it is noted that the term "first" 
has been used for those ends of the various parts of the apparatus which 
are engaged or operative during a bearing removal operation, as shown in 
FIGS. 1-3. Motive body 48 is advanced inwardly along first part 46a of the 
guide pin until it slides into the smaller diameter part 22 of the bearing 
housing 10, and then nut 66 is threaded onto pin part 46a outwardly of and 
abutting motive body 48, so that the entire assemblage is retained on the 
bearing housing 10. 
Then, the nut 66 is simply threaded inwardly along pin part 46a, forcing 
motive body 48 ahead of it. It is noted that the shoulder 24 in the 
bearing housing 10 is sized so that outer race 32 projects radially 
inwardly from the shoulder, and that diameter 54 of the motive body 48 is 
sized so that its end face 52 will overlap and abut the outer bearing race 
32. Thus, face 52 abuts both the inner and outer bearing races 32 and 34, 
and as the drive nut 66 is moved inwardly, the entire bearing 12 will be 
forced out of housing 10 and into the cavity formed by the interior of 
cylindrical body 38. During bearing removal, shoulder 60 serves as a stop 
against surface 16 of the bearing housing. Thereafter, the parts are 
simply disassembled by removing nut 66, removing motive body 48, and 
withdrawing body 38, with the removed bearing therein, from the housing 
10. 
To install a new bearing 32', 34', 36', the bracing body is placed on the 
second side of housing 10 so that the perpendicular end face 44 of its 
second end abuts the perpendicular end face 16 of the bearing housing. 
Thus, second pin part 46b will extend through the bearing housing 10 and 
beyond its first end surface 14. The new bearing 32', 34', 36' is emplaced 
on the second end of the motive body 48 so as to be carried thereby, and 
more specifically inner race 34' is slipped over small diameter part 54 
until the outer race 32' abuts the shoulder 62. It is noted that the 
recess 64 is sized so that shoulder 62 will clear inner race 34', as it is 
undesirable to apply pressure to the inner race while press fitting the 
outer race into the housing. Rather, the inner race 34' should be 
non-forcibly carried along by means of balls 36' interengaging the opposed 
grooves in the two bearing races. 
Motive body 48 is now emplaced on second pin part 46b with its second end 
55, 58 facing the housing 10, and the bearing carried by the second end of 
the motive body. The nut 66 is next threaded onto pin part 46b outwardly 
of but abutting motive body 48. 
The larger inner diameter 20 of the housing 10 typically has a slight 
outward taper which allows outer bearing race 32' to be started into the 
end of the housing without the application of substantial force, so as to 
temporarily coaxially align the tool with the bearing housing. Thereafter, 
nut 66 is threaded inwardly along pin part 46b, forcing motive body 48 and 
the bearing carried thereby ahead of it, and thus pressing race 32' into 
the large diameter 20 of the bearing housing 10 until the bearing abuts 
the internal shoulder 24. The tool is then simply removed by removing nut 
66, then motive body 48, then bracing body 48. 
When the tool is not is use, the motive body 48 can be placed on either of 
the pin parts 46a or 46b, and retained there by threading nut 66 onto that 
pin part outwardly of the motive body 48. Thus, all three parts of the 
tool are held together so as to minimize the possibility of their 
dissemination and/or loss. 
Certain modifications of the present invention have been suggested above, 
and still others will suggest themselves to those of skill in the art. By 
way of example only, motive body 48 has been shown as having a free 
sliding fit on the pin parts 46a and 46b, and a separate threaded drive 
nut 66 is provided. However, in other embodiments, the motive body 48 
could be directly threadedly engageable with pin parts 46a and 46b. This 
would further reduce the number of separable parts of the apparatus. 
However, in some instances, the addition of a third part, i.e. nut 66, may 
be considered to be balanced by the relative ease with which such a nut 
can be engaged and rotated by a wrench, possible undesirability of 
relative movement between the motive body 48 and the bearing 48 in use, 
and the relative ease of replacing nut 66, which can be an inexpensive, 
even standardized part. 
The use of a single reversible motive body 48, having the configurations of 
its two ends differing as needed to properly engage a bearing for 
respective removal and reinsertion procedures, is one salient feature of 
the invention which minimizes the necessary number of separable parts. 
However, in other embodiments, other salient features of the invention, 
e.g. the end surface of the bracing body inclined to match the inclination 
of the end of a special housing, or the integration of the guide pin with 
the bracing body, might be used with motive body means comprising two 
different motive bodies, one for bearing removal, and the other for 
bearing insertion. In such an embodiment, it is still possible to retain 
the motive bodies on the guide pin by one or two nuts, so as to minimize 
the chance of dissemination and loss thereof when the tool is not in use. 
It is intended that the scope of the invention be limited only by the 
claims which follow.