Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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BACKGROUND OF THE INYENTION
This invention relates in general to track rollers and, ~;~
in particular, to track rollers of the type utilizing anti-
friction bearings.
More specifically this invention relates to a track
roller utilizing anti-friction bearings positioned within the ;~
bearing bore a distance sufficient to overcome the adverse effects
of bearing bore growth caused by track roller bellmouthing.
In crawler type vehicles, wherein interconnected track
links support the vehicle weight by track rollers, a track roller
shell is carried upon a stationary track roller shaft by means
of bearing assemblies, usually tapered roller bearings. The
roller shell is formed with rim portions which engage the track
links as they pass thereunder in an endless path of movement.
During operation of such crawler type vehicles, the rims of the
roller shells are subjected to extremely heavy impact sufficient
to cause them to become enlarged and flared, a deteriorating
condition known in the industry as bellmouthing. The mechanical
working of the rim which causes bellmouthing not only creates ~-
20 problems with the tracking of the track links, but also causes ~
the bore in which the support bearings are pressed fit, to enlarge. `
Such bore growth results in separation between the hub and bearing
cup so that a loose bearing fit is produced. This loose fit
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allows the bearing cup to rotate in the bore resulting in the
destruction of the bearing and additional damage to the bearing
bore.
One attempted solution to this problem has been to use
so-called friction type bushings which are not as seriously
influenced by bore growth as anti-friction bearings. However,
such a "solution" has not been satisfactory as bushed rollers
have greater rolling resistance resulting in decreased overall
operating efficiency of the vehicle. ,
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SUMMARY OF THE INVENTION
It is, therefore, an object of this invention to im-
prove track rollers.
Another object of this invention is to prevent destruc- -
tion of the track roller bearing assemblies and bearing bore
caused by mechanical working of the track links adjacent the rim
of the roller shell.
These and other objects are attained in accordance with
the present invention wherein there is provided a track roller
having a roller shell supported for rotation about the track
roller shaft by means of tapered roller bearing assemblies posi-
tioned within a bearing bore such that the centers thereof are
spaced substantially inwardLy from the longitudinal center line
of the track links contacting the roller shell.
In accordance with a further broad apsect of the pre- ;
sent invention, there is provided a track roller for supporting
vehicle weight on the track links of a track laying vehicle in
an endless path of movement. The roller comprises a track roller
shell means having an outer portion for engaging track links
passing adjacent thereto in an endless path of movement and an
inner bearing bore for fixedly securing bearing means therein.
A track roller shaft supports the track roller shell means for
rotational movement thereabout. Bearing means, having inner and
outer bearing races and carried within the bearing bore upon the
track roller shaft, is provided for effecting rotational movement
of the track roller shell meanC about the track roller shaft. - i
The bearing means is positioned within the bearing bore such that
substantially all of the outer bearing race is spaced inwardly
in an axial direction from the track link engaging outer portion
of the track roller shell.
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DESCRIPTION OF THE DR~WINGS
Further objects of this invention, together with addi-
tional features contributing thereto and advantages accruing
therefrom, will be apparent from the following description of -
one embodiment of the invention when read in conjunction with
the accompanying drawings, wherein:
Fig. 1 is a perspective view of a track roller being
used to engage track links passing in an endless path of movement
in contact therewith: and
10Fig. 2 is a partial cross section view of the track
roller shown in Fig. 1, with portions removed, to better illus-
trate the positioning of the tapered roller bearings within the
bearin~ bore.
DESCRIPTION OF A PREFERRED EMBODIMENT
Referring now to Fig. 1 there is shown a track roller
100 in vehicle weight supporting relationship with a plurality
of interconnected track links 10 which pass adjacent to and in
contact with a rim portion l09 of a track roller shell 110. A
flange 108 is formed at the outer end of the rim portion of the
track roller shell 110 to maintain the passing track links in
proper alignment or tracking.
The track roller 100, shown in detail in Fig. 2, is
supported from a crawler type vehicle by means of a stationary
or dead shaft 120 appropriately secured to the vehicle to prevent
rotation such as by bolting the shaft 120 to appropriate frame
members. The txack roller shell 110 is rotatably supported on
the stationary shaft 120 by means of tapered roller bearing
assemblies 112 carried within a bearing bore 115 of a predeter-
mined size. The bearing assemblies 112 are pressed fit into
the bearing bore with the inner race or cone assembly 111 secured
to the stationary shaft and the outer race or bearing cup 113
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secured in the bearing bore 115 against the track roller shell
to permit rotation of the roller shell 110 about the stationary
shaft 120. This configuration of the bearings is commionly re-
ferred to in the industry as a cone-adjust configuration.
A preload force is applied to the bearing assemblies
112 in an axial direction by means of a washer 121 secured to the
shaft 120 applying a force against the bearing cone 111 through
tightening of a lock nut 122 threaded on the shaft 120 in a
manner commonly ~nown in the art.
The bearing assemblies 112 are sealed to prevent entry
of dirt, mud, or other debris which is always present in opera-
tional environment by means of a retainer 117 secured to the
track roller shell 110 acting in cooperation with another re- ;
tainer 118 fixed to the stationary shaft 120 with an appropriate
seal 119 between the two retainers 30 that these materials are
prevented from entering into the bearing assemblies 112. A
plurality of cap screws are provided in retainer 118 to assist
in removing the retainer from the support shaft 120 in the event ;
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it becomes necessary to repack the ~earing assemblies 112.
During operation of the crawler vehicle the track
links 10 passing in contact with the rim portion 109 of the track
roller shell 110 subject the track roller shell to heavy impact `
loading as previously discussed. This impact of the links 10
upon the track roller shell 110 causes the rim portion 109 to
become enlarged~ or as referred to in the industry as bellmouthing.
This bellmouthing has the effect of causing the bearing bore to
enlarge. The greatest increase in bearing bore diameter occurs
at the end of the roller in the area beneath the point of contact
between the track links and the track roller and decreases toward
the center of the track roller, that portion removed from the
impact area. The tapered roller bearing assemblies 112 are pressed
fit into the bearing bore to a position inward from the contact
area where the track links 10 impact against the track roller
shell 110.
As best shown in Fig. 2, the center of the tapered ;
roller bearing assemblies:~ll2, defined as a point 130 on the bore
center line 131 crossed by a line 132 drawn at right angles from
the center of the bearing roller, is spaced substantially inward
from the center of the impact area or the longitudinal center line
133 of the track links 10 passing in contact with the rim portion
lO9 of the track roller shell. Preferably the center 130 of the
bearing assemblies 112 is spaced at or inward from the rim
~;~ 25 portion 109 of the roller shell which contacts the track links.
Such positioning of the tapered roller bearing assemblies 112 has
been found to permit the satisfactory use of anti-friction pre-
ssed fit bearings. Since the bore growth problem is overcome, '
the press fit of the bearing assemblies remains sufficient to
prevent rotation of the bearing cup 113 and even results in an
increase in the press fit at the inner~,end of the bearing cup. ` ;
While the invention has been described with reference ~
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to a preferred em~odiment, it will be understood by those skilled
in the art that VariQuS changes may be made and equivalents may
be substituted for elements thereof without departing from the
scope of the invention. In addition, many modifications may be
made to adapt a particular situation or material to the teachings
of the invention without departing from the essential scope
thereof. Therefore, it is intended that the invention not be
limited to the particular embodiment disclosed as the best mode
contemplated for carrying out this invention, but that the
invention will include all embodiments falling within the scope
of the appended claims.
