CA1060514A

CA1060514A - Track roller

Info

Publication number: CA1060514A
Application number: CA267,723A
Authority: CA
Inventors: Bernard J. Murphy
Original assignee: Fiat Allis Construction Machinery Inc
Current assignee: Fiat Allis Construction Machinery Inc
Priority date: 1976-01-05
Filing date: 1976-12-13
Publication date: 1979-08-14
Also published as: AU2072576A; BR7608827A; AU509168B2; JPS5284652A; FR2337071B1; DE2658261A1; GB1565818A; IT1065371B; FR2337071A1

Abstract

T R A C K R O L L E R

ABSTRACT OF THE DISCLOSURE

A track roller for use in supporting vehicle weight on the endless tracks of a crawler type vehicle. A roller shell for carrying the vehicle weight is supported for rotational move-ment about a stationary track roller shaft by means of a pair of axially spaced, tapered roller bearing assemblies secured in a bearing bore formed in the roller shell. The center of the bearing assemblies is positioned inwardly of the longitudinal center line or axis of the track links engaged by the roller shell.

Description

, :
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 : ..
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. , ,. .
~ ',,.

- 2 - q~P

- " 1060514 -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.

-` ~o605~4 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 , :: .

, 1060514 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 ;

- 4a - ~: :

. . ., , , , " , , , . ., ~, , . , , .: ~.

~060514 ,~ , 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 ~
'.". . ..
- 5 ~

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.

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:-

1. A track roller for supporting vehicle weight on the track links of a track laying vehicle in an endless path of movement comprising 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 supporting said track roller shell means for rotational movement thereabout, bearing means having inner and outer bearing races and carried within said bearing bore upon said track roller shaft for effecting rotational movement of said track roller shell means about said track roller shaft, and said bearing means positioned within said bearing bore such that substantially all of said outer bearing race is spaced inwardly in an axial direction from said track link en-gaging outer portion of said track roller shell.

2. The apparatus of claim 1 wherein said bearing means is positioned within said bearing bore such that the center of said bearing means is spaced laterally inward of the longitudinal axis of track links passing in adjacent contact with the outer portion of said track roller shell means.

3. The apparatus of claim 1 wherein said bearing means is positioned within said bearing bore such that the center of said bearing means is spaced laterally inward of the outer por-tion of said track roller shell means engaged by track links passing in adjacent contact therewith.

4. The apparatus of claim 3 wherein said bearing means includes tapered roller bearings carried between inner and outer bearing races with the inner bearing race secured on said track roller shaft and the outer bearing race secured in said bearing bore.

5. The apparatus of claim 3 further including means for providing an axially directed loading force against said bearing means.

6. The apparatus of claim 3 further including sealing means for sealing said bearing means during operation of the track roller.

7. The apparatus of claim 1 wherein said bearing means is a tapered roller bearing means carried within said bearing bore upon said track roller shaft in a cone-adjust configuration, said outer bearing race being positioned in contact with a por-tion of said track roller shell fixedly securing said outer race against inward lateral movement relative thereto and said inner bearing race being carried on said track roller shaft for lateral movement relative thereto.

8. The apparatus of claim 7 wherein said tapered roller bearing means is positioned within said bearing bore such that the center of said tapered roller bearing means is spaced later-ally inward of the portion of said track roller shell means con-tacted by track links passing adjacent thereto.

9. The apparatus of claim 7 further including means for providing an axially directed loading force against said bearing means.

10. The apparatus of claim 7 further including sealing means for sealing said bearing means during operation of the track roller.