Series arrangement of hydraulic chain tensioner and ratchet

Patent metadata

Field	Value
Publication number	US-9874267-B2
Application number	US-201414891029-A
Country	US
Kind code	B2
Filing date	May 15, 2014
Priority date	May 24, 2013
Publication date	Jan 23, 2018
Grant date	Jan 23, 2018

Abstract

A tensioner ( 10 ) for an endless loop power transmission member can induce a piston ( 12 ) operably engageable with an endless loop power transmission member, and a cylinder ( 14 ) guiding include a piston ( 12 ) for sliding coaxial movement in a direction of the endless loop power transmission member. The piston ( 12 ) and cylinder ( 14 ) defining an oil reservoir or pressure chamber ( 26 ) for receiving hydraulic fluid. A bearing ( 28 ) has bearing balls ( 30 ) located in a counter bore ( 32 ) coaxial with cylinder bore ( 34 ). The counter bore ( 32 ) has a steep taper ( 36 ) on which the bearing balls ( 30 ) ride. As the cylinder ( 14 ) moves in an extending direction, the bearing balls ( 30 ) move out of the counter bore ( 32 ) allowing free extending movement of the cylinder ( 14 ). As the cylinder ( 14 ) moves in a retracting direction, the bearing balls ( 30 ) are driven down into the steep taper ( 36 ) preventing the cylinder ( 14 ) from retracting.

First claim

What is claimed is:

1. A tensioner ( 10 ) for an endless loop power transmission member comprising:
a piston ( 12 ) operably engageable with an endless loop power transmission member;
a cylinder ( 14 ) guiding the piston ( 12 ) for sliding coaxial movement in a direction of the endless loop power transmission member and defining an oil reservoir ( 26 ) for receiving hydraulic fluid;
a bearing ( 28 ) having bearing balls ( 30 ) located in a counter bore ( 32 ) coaxial with cylinder bore ( 34 ), the counter bore ( 32 ) having a steep taper ( 36 ) on which the bearing balls ( 30 ) ride, such that as the cylinder ( 14 ) moves in an extending direction, the bearing balls ( 30 ) move out of the counter bore ( 32 ) allowing free extending movement of the cylinder ( 14 ), and such that as the cylinder ( 14 ) moves in a retracting direction, the bearing balls ( 30 ) are driven down into the steep taper ( 36 ) preventing the cylinder ( 14 ) from retracting; and
a circular clip ( 38 ) retained within a groove in an inside diameter (ID) of the piston ( 12 ), wherein
the cylinder ( 14 ) has a groove ( 40 ) of given width on the cylinder ( 14 ) in which the circular clip ( 38 ) rides, the given width corresponding to an allowable backlash for the tensioner ( 10 ).

2. The tensioner ( 10 ) of claim 1 further comprising:
an end wall of the groove ( 40 ) coming into contact with the circular clip ( 38 ) during extending movement, such that the circular clip ( 38 ) pulls the cylinder ( 14 ) with the circular clip ( 38 ) resulting in endless loop power transmission member slack take-up.

3. The tensioner ( 10 ) of claim 2 further comprising:
a bias spring ( 42 ) acting between the bearing ( 28 ) and piston ( 12 ), the bias spring ( 42 ) serving to bias the piston ( 12 ) out of the cylinder ( 14 ) when the circular clip ( 38 ) contacts the end wall of the groove ( 40 ) resulting in extension and endless loop power transmission member take-up.

4. The tensioner ( 10 ) of claim 1 further comprising: a check valve ( 16 ) located between the piston ( 12 ) and cylinder ( 14 ).

5. The tensioner ( 10 ) of claim 4 further comprising: a piston spring ( 18 ) located between the piston ( 12 ) and cylinder ( 14 ).

6. The tensioner ( 10 ) of claim 5 further comprising: a flow control device ( 20 ) creating hydraulic tensioner functions.

7. The tensioner ( 10 ) of claim 1 further comprising: an oil groove ( 22 ) formed within the bore ( 34 ) of the cylinder ( 14 ).

8. The tensioner ( 10 ) of claim 7 further comprising: the oil groove ( 22 ) formed as an annulus allowing for consistent oil feed as the cylinder ( 14 ) moves without creating a hydraulic bias on the cylinder ( 14 ).

9. The tensioner ( 10 ) of claim 7 further comprising: the oil groove ( 22 ) having an oil feed ( 22 a ) to a center of the cylinder ( 14 ).

10. The tensioner ( 10 ) of claim 1 further comprising: a plug ( 24 ) pressed into an end of the cylinder ( 14 ) forming the oil reservoir ( 26 ) of the tensioner ( 10 ), the oil reservoir ( 26 ) fed through a check valve ( 16 ).

11. An assembly for take-up of wear in an endless loop power transmission system comprising:
a hydraulic tensioner ( 10 ) having a piston ( 12 ), a cylinder ( 14 ), a piston/cylinder spring ( 18 ), and a check valve ( 16 ) for providing less distance at a full travel stroke than required for take-up of full wear of the endless loop power transmission system; and
a zero backlash ratchet including a bearing ( 28 ) with bearing balls ( 30 ), a counter bore ( 32 ), a steep taper ( 36 ), and a cylinder/bearing spring, the zero backlash ratchet attached in series with the hydraulic tensioner ( 10 ) for extending only when the hydraulic tensioner ( 10 ) has reached the full travel stroke, thereby repositioning the hydraulic tensioner ( 10 ) to continue operation as the endless loop power transmission system continues to wear.

12. The assembly of claim 11 further comprising:
the piston/cylinder spring ( 18 ) located in series with the cylinder/bearing spring ( 42 ) and providing a higher force to assure that the zero backlash ratchet only extends when the hydraulic tensioner ( 10 ) is fully extended, guaranteeing that a minimum backlash is maintained in the tensioner ( 10 ).

13. A tensioner ( 10 ) for an endless loop power transmission member comprising:
a piston ( 12 ) operably engageable with an endless loop power transmission member;
a cylinder ( 14 ) guiding the piston ( 12 ) for sliding coaxial movement in a direction of the endless loop power transmission member and defining an oil reservoir ( 26 ) for receiving hydraulic fluid;
a bearing ( 28 ) having bearing balls ( 30 ) located in a counter bore ( 32 ) coaxial with cylinder bore ( 34 ), the counter bore ( 32 ) having a steep taper ( 36 ) on which the bearing balls ( 30 ) ride, such that as the cylinder ( 14 ) moves in an extending direction, the bearing balls ( 30 ) move out of the counter bore ( 32 ) allowing free extending movement of the cylinder ( 14 ), and such that as the cylinder ( 14 ) moves in a retracting direction, the bearing balls ( 30 ) are driven down into the steep taper ( 36 ) preventing the cylinder ( 14 ) from retracting;
a circular clip ( 38 ) retained within a groove in an inside diameter (ID) of the piston ( 12 ), wherein the cylinder ( 14 ) has a groove ( 40 ) of given width on the cylinder ( 14 ) in which the circular clip ( 38 ) rides, the given width corresponding to an allowable backlash for the tensioner ( 10 );
an end wall of the groove ( 40 ) coming into contact with the circular clip ( 38 ) during extending movement, such that the circular clip ( 38 ) pulls the cylinder ( 14 ) with the circular clip ( 38 ) resulting in endless loop power transmission member slack take-up;
a bias spring ( 42 ) acting between the bearing ( 28 ) and piston ( 12 ), the bias spring ( 42 ) serving to bias the piston ( 12 ) out of the cylinder ( 14 ) when the circular clip ( 38 ) contacts the end wall of the groove ( 40 ) resulting in extension and endless loop power transmission member take-up; and
a check valve ( 16 ) located between the piston ( 12 ) and cylinder ( 14 ).

14. The tensioner ( 10 ) of claim 13 further comprising: a piston spring ( 18 ) located between the piston ( 12 ) and cylinder ( 14 ).

15. The tensioner ( 10 ) of claim 14 further comprising: a flow control device ( 20 ) creating hydraulic tensioner functions.

16. The tensioner ( 10 ) of claim 13 further comprising: an oil groove ( 22 ) formed within the bore ( 34 ) of the cylinder ( 14 ).

17. The tensioner ( 10 ) of claim 16 further comprising: the oil groove ( 22 ) formed as an annulus allowing for consistent oil feed as the cylinder ( 14 ) moves without creating a hydraulic bias on the cylinder ( 14 ).

18. The tensioner ( 10 ) of claim 16 further comprising: the oil groove ( 22 ) having an oil feed ( 22 a ) to a center of the cylinder ( 14 ).

19. The tensioner ( 10 ) of claim 13 further comprising: a plug ( 24 ) pressed into an end of the cylinder ( 14 ) forming the oil reservoir ( 26 ) of the tensioner ( 10 ), the oil reservoir ( 26 ) fed through a check valve ( 16 ).

Assignees

• Borgwarner Inc

Inventors

• Wigsten Mark M
• Smith Dale N

Classifications

• F16H2007/0817

  with means for venting unwanted gas · CPC title

• F16H2007/0853

  Ratchets · CPC title

• F16H2007/0812

  Fluid pressure · CPC title

• F16H2007/0851

  Wedges · CPC title

• F16H2007/0806

  Compression coil springs · CPC title