Expanding piston hydraulic chain tensioner

Patent metadata

Field	Value
Publication number	US-9605732-B2
Application number	US-201414903860-A
Country	US
Kind code	B2
Filing date	Jul 7, 2014
Priority date	Jul 10, 2013
Publication date	Mar 28, 2017
Grant date	Mar 28, 2017

Abstract

A tensioner ( 10 ) for an endless loop power transmission member can include the assembly of a plunger ( 12 ) operably engageable with an endless loop power transmission member, and a piston ( 14 ) guiding the plunger ( 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 ) can have bearing balls ( 30 ) located in a counter bore ( 32 ) coaxial with piston bore ( 34 ). The counter bore ( 32 ) can have a steep taper ( 36 ) on which the bearing balls ( 30 ) ride, such that as the plunger ( 12 ) moves in an extending direction, the bearing balls ( 30 ) move out of the counter bore ( 32 ) allowing free extending movement of the plunger ( 12 ), and as the plunger ( 12 ) moves in a retracting direction, the bearing balls ( 30 ) are driven down into the steep taper ( 36 ) preventing the plunger ( 12 ) from retracting.

First claim

What is claimed is:

1. A tensioner ( 10 ) for an endless loop power transmission member comprising:
a plunger ( 12 ) operably engageable with an endless loop power transmission member;
a piston ( 14 ) guiding the plunger ( 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; and
a bearing ( 28 ) having bearing balls ( 30 ) located in a counter bore ( 32 ) coaxial with piston bore ( 34 ), the counter bore ( 32 ) having a steep taper ( 36 ) on which the bearing balls ( 30 ) ride, such that as the plunger ( 12 ) moves in an extending direction, the bearing balls ( 30 ) move out of the counter bore ( 32 ) allowing free extending movement of the plunger ( 12 ), and such that as the plunger ( 12 ) moves in a retracting direction, the bearing balls ( 30 ) are driven down into the steep taper ( 36 ) preventing the plunger ( 12 ) from retracting.

2. The tensioner ( 10 ) of claim 1 further comprising:
a cylinder ( 50 ) having a bore ( 52 ) for guiding the piston ( 14 ) for sliding coaxial movement in a direction of the endless loop power transmission member and defining an oil reservoir ( 26 ) for receiving hydraulic fluid therebetween; and
a circular clip ( 38 ) retained within a groove in an inside diameter (ID) of the cylinder ( 50 ).

3. The tensioner ( 10 ) of claim 2 further comprising:
the piston ( 14 ) having a groove ( 40 ) of given width on the piston ( 14 ) in which the circular clip ( 38 ) rides, the given width corresponding to an allowable backlash for the tensioner ( 10 ).

4. The tensioner ( 10 ) of claim 3 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 ) stops the piston ( 14 ) with the circular clip ( 38 ).

5. The tensioner ( 10 ) of claim 4 further comprising:
a bias spring ( 42 ) acting between the bearing ( 28 ) and plunger ( 12 ), the bias spring ( 42 ) serving to bias the plunger ( 12 ) out of the piston ( 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.

6. The tensioner ( 10 ) of claim 1 further comprising:
a cylinder ( 50 ) having a bore ( 52 ) for guiding the piston ( 14 ) for sliding coaxial movement in a direction of the endless loop power transmission member and defining an oil reservoir ( 26 ) for receiving hydraulic fluid therebetween; and
a check valve ( 16 ) located between the cylinder ( 50 ) and piston ( 14 ).

7. The tensioner ( 10 ) of claim 6 further comprising:
a piston spring ( 18 ) located between the cylinder ( 50 ) and piston ( 14 ); and
a bias spring ( 42 ) acting between the bearing ( 28 ) and plunger ( 12 ) located in series with the piston spring ( 18 ), wherein the piston spring ( 18 ) provides a higher force so that the plunger ( 12 ) only extends when the hydraulic tensioner ( 10 ) is fully extended, guaranteeing that a minimum backlash is maintained in the tensioner ( 10 ).

8. The tensioner ( 10 ) of claim 7 further comprising:
a flow control device ( 20 ) creating hydraulic tensioner functions.

9. A tensioner ( 10 ) for an endless loop power transmission member comprising:
a plunger ( 12 ) operably engageable with an endless loop power transmission member;
a piston ( 14 ) guiding the plunger ( 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 piston bore ( 34 ), the counter bore ( 32 ) having a steep taper ( 36 ) on which the bearing balls ( 30 ) ride, such that as the plunger ( 12 ) moves in an extending direction, the bearing balls ( 30 ) move out of the counter bore ( 32 ) allowing free extending movement of the plunger ( 12 ), and such that as the plunger ( 12 ) moves in a retracting direction, the bearing balls ( 30 ) are driven down into the steep taper ( 36 ) preventing the plunger ( 12 ) from retracting; and
a bias spring ( 42 ) acting between the bearing ( 28 ) and plunger ( 12 ), the biasing spring ( 42 ) serving to bias the plunger ( 12 ) out of the piston ( 14 ) resulting in extension and endless loop power transmission member take-up.

10. The tensioner ( 10 ) of claim 9 further comprising:
a cylinder ( 50 ) having a bore ( 52 ) for guiding the piston ( 14 ) for sliding coaxial movement in a direction of the endless loop power transmission member and defining an oil reservoir ( 26 ) for receiving hydraulic fluid therebetween; and
a circular clip ( 38 ) retained within a groove in an inside diameter (ID) of the cylinder ( 50 ).

11. The tensioner ( 10 ) of claim 10 further comprising:
the piston ( 14 ) having a groove ( 40 ) of given width on the piston ( 14 ) in which the circular clip ( 38 ) rides, the given width corresponding to an allowable backlash for the tensioner ( 10 ).

12. The tensioner ( 10 ) of claim 11 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 ) stops the piston ( 14 ) with the circular clip ( 38 ).

13. The tensioner ( 10 ) of claim 9 further comprising:
a cylinder ( 50 ) having a bore ( 52 ) for guiding the piston ( 14 ) for sliding coaxial movement in a direction of the endless loop power transmission member and defining an oil reservoir ( 26 ) for receiving hydraulic fluid therebetween; and
a check valve ( 16 ) located between the cylinder ( 50 ) and piston ( 14 ).

14. The tensioner ( 10 ) of claim 13 further comprising:
a piston spring ( 18 ) located between the cylinder ( 50 ) and piston ( 14 ); and
a bias spring ( 42 ) acting between the bearing ( 28 ) and plunger ( 12 ) located in series with the piston spring ( 18 ), wherein the piston spring ( 18 ) provides a higher force so that the plunger ( 12 ) only extends when the hydraulic tensioner ( 10 ) is fully extended, guaranteeing that a minimum backlash is maintained in the tensioner ( 10 ).

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

Assignees

• Borgwarner Inc
• Borgwarner Inc

Inventors

• Smith Dale N
• Wigsten Mark

Classifications

• F16H2007/0812

  Fluid pressure · CPC title

• F16H7/0848 Primary

  with means for impeding reverse motion · CPC title

• F16H2007/0859

  Check valves · CPC title

• F16H2007/0806

  Compression coil springs · CPC title

• F16H7/08 Primary

  Means for varying tension of belts, ropes or chains  (pulleys of adjustable construction F16H55/52) · CPC title