Tensioner with expanding spring for radial frictional asymmetric damping

Patent metadata

Field	Value
Publication number	US-9394977-B2
Application number	US-201313834989-A
Country	US
Kind code	B2
Filing date	Mar 15, 2013
Priority date	Mar 15, 2013
Publication date	Jul 19, 2016
Grant date	Jul 19, 2016

Abstract

A tensioner is disclosed that may be part of a power system where the tensioner provides tension to an endless power transmitting element such as a belt, chain, or other continuous loop. The tensioner has an arm that is rotatable about a first axis and includes an arm arbor having a window therethrough, a bushing having a protrusion and being positioned adjacent the arm arbor with the protrusion received in the arm arbor's window, and a spring coupled to the arm urging the arm to rotate about the first axis into tensioning engagement with a power transmitting element. The spring is positioned where it can radially expand into contact with the protrusion of the bushing as the arm is rotated in a direction opposite the direction of tensioning engagement such that the bushing is urged radially outward relative to the arm arbor to provide frictional damping.

First claim

What is claimed is:

1. A tensioner comprising:
an arm rotatable about a first axis, the arm comprising an arm arbor having a slot through a portion thereof and having a spring support;
a bushing having a protrusion wherein the bushing includes a longitudinal slit that allows radial expansion and splits the protrusion into a first part and a second part;
a spring coupled to the arm urging the arm to rotate about the first axis into tensioning engagement with an endless power transmitting element;
a cap having a spring abutment feature, the cap enclosing the spring within the tensioner;
wherein the bushing surrounds the arm arbor and is positioned with the protrusion extending through the slot of the arm arbor;
wherein the spring has a first end coupled to the arm and a second end coupled to the cap and is positioned to radially expand into contact with the protrusion of the bushing as the arm is rotated in a direction opposite the direction of tensioning engagement such that the bushing is urged radially outward relative to the arm arbor to provide frictional damping;
wherein the slot of the arm arbor is positioned about 30 degree from the spring abutment feature of the cap, and the spring support of the arm arbor is positioned at or between 90 degree through 180 degrees from the spring abutment feature of the cap, thereby providing damping of about 60 in-lb to about 80 in-lb with a tensioner torque of between about 150 in-lb to about 200 in-lb.

2. The tensioner of claim 1 , wherein the bushing comprises a sleeve that includes the slit and the protrusion and comprises a flange extending outward from one end of the sleeve.

3. The tensioner of claim 2 wherein the sleeve of the bushing is substantially cylindrical.

4. The tensioner of claim 2 wherein the arm arbor has a fixed diameter.

5. The tensioner of claim 1 wherein the arm includes a pulley rotatably mounted about a second axis, the second axis being spaced from and parallel to the first axis.

6. The tensioner of claim 1 further comprising a support member housing the spring, the arm arbor, and the bushing with the bushing adjacent the support member and the arm arbor between the spring and the bushing.

7. The tensioner of claim 6 wherein the radial expansion of the spring urges the first and second parts of the protrusion into frictional engagement with the slot and urges the bushing into frictional engagement with the support member to provide the frictional damping.

8. The tensioner of claim 6 wherein the support member is stationary and includes a shaft that defines the first axis, wherein the arm is rotatably mounted to the shaft.

9. The tensioner of claim 1 wherein the spring support is at a position at or between 90 degrees and 105 degrees from the spring abutment feature.

10. A tensioner comprising:
a support member comprising a shaft defining a first axis;
an arm comprising an arm arbor mounted on said shaft for rotatable movement of the arm about the first axis, the arm arbor defining a cavity and having a slot open into the cavity;
a bushing having a protrusion receivable in the slot of the arm arbor, wherein the bushing is between the support member and the arm with the protrusion received in the slot, and wherein the bushing includes a longitudinal slit that allows radial expansion and splits the protrusion into a first part and a second part;
a spring received in the cavity of the arm arbor and coupled to the arm urging the arm to rotate about the first axis into tensioning engagement with a power transmitting element, the spring being positioned to radially expand into contact with the protrusion of the bushing as the arm is rotated in a direction opposite the direction of tensioning engagement such that the first and second parts of the protrusion are urged into frictional engagement with the slot, and the bushing is urged radially outward relative to the arm arbor into frictional engagement with the support member to provide frictional damping;
a cap having the spring coupled thereto;
wherein the cap includes a spring abutment feature and the slot of the arm arbor is positioned about 30 degree therefrom, wherein the arm arbor further comprises a spring support positioned to contact the spring when it radially expands and positioned at or between 90 degrees through 135 degrees from the spring abutment feature, thereby providing damping of about 60 in-lb to about 70 in-lb with a tensioner torque of about 175 in-lb to about 200 in-lb.

11. The tensioner of claim 10 wherein the bushing comprises a substantially cylindrical sleeve that includes the slit and the protrusion and comprises a flange extending outward from one end of the sleeve.

12. The tensioner of claim 10 wherein the arm arbor has a fixed diameter.

13. The tensioner of claim 10 wherein the arm includes a pulley rotatably mounted about a second axis, the second axis being spaced from and parallel to the first axis.

14. The tensioner of claim 10 wherein the arm arbor comprises a generally cylindrical sleeve having an open first end and a partial bottom that defines an open second end that has a smaller opening compared to the first end.

15. The tensioner of claim 14 wherein the slot extends through the sleeve and into the partial bottom.

16. The tensioner of claim 10 wherein the spring support is at a position at or between 90 degrees and 105 degrees from the spring abutment feature.

Assignees

• Dutil Kevin Gerard
• Lannutti Anthony Eugene
• Dayco Ip Holdings Llc

Inventors

• Dutil Kevin Gerard
• Lannutti Anthony Eugene

Classifications

• F16H7/1218 Primary

  of the dry friction type · CPC title

• F16H2007/084

  having vibration damping characteristics dependent on the moving direction of the tensioner · CPC title

• F16H7/0831

  of the dry friction type · CPC title

• F16H2007/081

  Torsion springs · CPC title

• F16H2007/0893

  Circular path · CPC title