Rotatable element in machine track having thrust washer stack for stepping down relative speeds

Patent metadata

Field	Value
Publication number	US-11654983-B2
Application number	US-201916436209-A
Country	US
Kind code	B2
Filing date	Jun 10, 2019
Priority date	Jun 10, 2019
Publication date	May 23, 2023
Grant date	May 23, 2023

Abstract

A sealed and lubricated rotatable track engaging element includes a roller and a roller shaft extending through the roller to support the roller for rotation about a major axis. A first thrust surface is fixed relative to the roller, and a second thrust surface is fixed relative to the roller shaft. A seal cavity extends between the roller and the roller shaft and is formed in part by each of the first thrust surface and the second thrust surface, and a thrust washer stack is within the seal cavity and trapped between the first thrust surface and the second thrust surface. The thrust washer stack includes an inner thrust washer contacting the roller to rotate at a first fractional speed of a speed of rotation of the roller, and an outer thrust washer contacting the inner thrust washer and the collar to rotate at a second fractional speed that is less than the first fractional speed.

First claim

What is claimed is:

1. An undercarriage assembly comprising:
a roller having a bore formed therein defining a major axis;
a roller shaft extending through the bore to support the roller for rotation about the major axis;
a seal cavity extending between the roller and the roller shaft and formed in part by a first thrust surface that faces a first axial direction and is fixed relative to the roller, and a second thrust surface that faces a second axial direction opposite to the first axial direction and is fixed relative to the roller shaft;
a thrust washer stack trapped between the first thrust surface and the second thrust surface, to react thrust loads between the roller and the roller shaft, and including a first thrust washer in contact with the first thrust surface and rotatable at a first fractional speed of a speed of rotation of the roller, and a second thrust washer in contact with the second thrust surface and rotatable at a second fractional speed of rotation of the roller different from the first fractional speed of rotation; and
a dynamic seal fluidly sealing the thrust washer stack within the seal cavity.

2. The undercarriage assembly of claim 1 wherein the second thrust washer is in contact with the first thrust washer and each of the first thrust washer and the second thrust washer is free to rotate about the major axis.

3. The undercarriage assembly of claim 2 wherein the dynamic seal includes a face seal assembly including a sealing ring and a seal biaser.

4. The undercarriage assembly of claim 3 further comprising a collar, and one of the first thrust surface or the second thrust surface is formed on the collar.

5. The undercarriage assembly of claim 4 wherein:
the first thrust surface is formed on the collar, and the collar is bolted to the roller and includes a seal carrier rotatable with the roller about the major axis; and
the second thrust surface is formed on the roller shaft.

6. The undercarriage assembly of claim 5 wherein:
the roller includes an idler hub and an idler rim; and
the first axial direction is an axially inward direction and the second axial direction is an axially outward direction.

7. The undercarriage assembly of claim 4 wherein:
the second thrust surface is formed on the collar, and the collar is fixed to the roller shaft and includes a seal carrier; and
the first thrust surface is formed on the roller.

8. The undercarriage assembly of claim 7 further comprising an idler and a drive sprocket, and the roller includes a roller shell in a track roller; and
the first axial direction is an axially outward direction and the second axial direction is an axially inward direction.

9. A rotatable track engaging element for a machine track comprising:
a roller shaft having a first shaft end and a second shaft end;
a roller defining a major axis and being positioned upon the roller shaft;
a first shaft support structured to mount to a frame and receiving the first shaft end;
a second shaft support structured to mount to the frame and receiving the second shaft end;
a first thrust washer stack positioned upon the roller shaft and including a first plurality of thrust washers trapped between the first shaft support and the roller, wherein each thrust washer of the first plurality of thrust washers is rotatable at different fractional speeds of a speed of rotation of the roller; and
a second thrust washer stack positioned upon the roller shaft and including a second plurality of thrust washers trapped between the second shaft support and the roller, wherein each thrust washer of the second plurality of thrust washers is rotatable at different fractional speeds of the speed of rotation of the roller.

10. The rotatable track engaging element of claim 9 wherein:
the first shaft support includes a first collar and the second shaft support includes a second collar; and
the first thrust washer stack is in contact with at least one of the roller or the roller shaft, and the second thrust washer stack is in contact with at least one of the roller or the roller shaft.

11. The rotatable track engaging element of claim 10 wherein:
the first thrust washer stack is positioned to contact each of the roller and the first collar to directly react thrust loads between the roller and the first collar;
the second thrust washer stack is positioned to contact each of the roller and the second collar to directly react thrust loads between the roller and the second collar; and
each of the first shaft support and the second shaft support further includes a pin fixing the roller shaft to the corresponding first collar or second collar.

12. The rotatable track engaging element of claim 11 further comprising:
a first dynamic seal positioned between the roller and the first collar and fluidly sealing the first thrust washer stack within the rotatable track engaging element; and
a second dynamic seal positioned between the roller and the second shaft support and fluidly sealing the second thrust washer stack within the rotatable track engaging element.

13. The rotatable track engaging element of claim 10 including a total of two thrust washers in each of the first thrust washer stack and the second thrust washer stack, and the plurality of thrust washers of each of the first thrust washer stack and the second thrust washer stack are substantially identical to one another.

14. The rotatable track engaging element of claim 13 including a track roller where the roller includes a roller shell.

15. A sealed and lubricated rotatable track engaging element comprising:
a roller having a bore formed therein defining a major axis;
a roller shaft extending through the bore to support the roller for rotation about the major axis;
a first thrust surface fixed relative to the roller and facing a first axial direction;
a second thrust surface fixed relative to the roller shaft and facing a second axial direction;
a seal cavity extending between the roller and the roller shaft and formed in part by each of the first thrust surface and the second thrust surface;
a thrust washer stack within the seal cavity and trapped between the first thrust surface and the second thrust surface; and
the thrust washer stack including a first thrust washer in contact with the first thrust surface and rotatable at a first fractional speed of a speed of rotation of the roller, and a second thrust washer in contact with the second thrust surface and rotatable at a second fractional speed of a speed of rotation of the roller different from the first fractional speed of rotation.

16. The rotatable track engaging element of claim 15 wherein the roller includes the first thrust surface, and further comprising a collar that includes the second thrust surface, and a pin fixing the collar to the roller shaft.

17. The rotatable track engaging element of claim 16 wherein the roller includes a first seal carrier and the collar includes a second seal carrier, and further comprising a dynamic seal fluidly sealing the seal cavity.

18. The rotatable track engaging element of claim 17 wherein the thrust washer stack includes a total of two thrust washers.

19. The rotatable track engaging element of claim 18 wherein:
the first thrust washer including an inner thrust washer, and the second thrust washer including an outer thrust washer, and each of the inner thrust washer and the outer thrust washer is free to rotate about the major axis; and
the inner thrust washer contacts the roller to rotate at a first fractional speed of a

Assignees

• Caterpillar Inc

Inventors

• Abello Benoit
• Palthey-Glomeau Paul
• Loeffler Brian
• Hakes David Jennings

Classifications

• B62D55/0887 Primary

  Track-articulation sealings against dust, water, mud or the like (sealing of bearings in general F16C33/72; chain bushings in general F16G15/00) · CPC title

• F16C17/045

  with grooves in the bearing surface to generate hydrodynamic pressure, e.g. spiral groove thrust bearings · CPC title

• F16C33/761

  specifically for bearings with purely axial load · CPC title

• F16H41/24

  Details · CPC title

• B62D55/15 Primary

  Mounting devices, e.g. bushings, axles, bearings, sealings {(with lubrication means B62D55/092)} · CPC title