Low profile switchable finger follower

Patent metadata

Field	Value
Publication number	US-10100684-B2
Application number	US-201615233145-A
Country	US
Kind code	B2
Filing date	Aug 10, 2016
Priority date	Aug 10, 2016
Publication date	Oct 16, 2018
Grant date	Oct 16, 2018

Abstract

A switchable finger follower is provided having an inner lever with a sliding pad located between first and second inner lever ends. The sliding pad has at least one of an anti-friction coating or a surface finish of Ra 0.05 or better forming a cam contact surface. An outer lever supports the inner lever, and includes a first outer lever end mounted for pivoting movement at the first end of the inner lever by a pivot axle. A coupling pin is arranged on one of the inner or outer levers on an end opposite from the pivot axle. The coupling pin has a coupling projection with a first locking surface, and is moveable from a first, locked position with the first locking surface engaged with a second locking surface located on the other of the inner lever or the outer lever, to a second, unlocked position. A lost motion element is arranged between the inner lever and the outer lever.

First claim

What is claimed is:

1. A switchable finger follower comprising:
an inner lever having first and second inner lever ends, a sliding pad located between the first and second inner lever ends, the sliding pad having at least one of an anti-friction coating or a surface finish of Ra 0.05 or better forming a cam contact surface, the inner lever having an I-beam shaped cross-section in an area of the sliding pad, defining two pockets in the inner lever;
an outer lever having two outer arms that extend along longitudinal sides of the inner lever, and a first outer lever end mounted for pivoting movement at the first end of the inner lever by a pivot axle;
a coupling pin arranged to move longitudinally within a coupling pin bore located on one of the inner lever or the outer lever on an end opposite from the pivot axle, the coupling pin having a coupling projection with a first locking surface;
the coupling pin is moveable from a first, locked position with the first locking surface engaged with a second locking surface located on the other of the inner lever or the outer lever, to a second, unlocked position where the first locking surface is not engaged with the second locking surface; and
a lost motion element arranged between the inner lever and the outer lever.

2. The switchable finger follower of claim 1 , wherein the sliding pad includes the anti-friction coating which comprises a DLC coating.

3. The switchable finger follower of claim 1 , wherein a height of the inner lever in an area of the sliding pad is in a range of 30% to 50% of a radius of curvature of the sliding pad.

4. The switchable finger follower of claim 3 , wherein the height of the inner lever in the area of the sliding pad is in a range of 45%-50% of the radius of curvature of the sliding pad.

5. The switchable finger follower of claim 1 , wherein a combined width of the pockets (2*Wp) is at least 4 times a thickness of a web of the I-beam shaped cross-section.

6. The switchable finger follower of claim 1 , wherein the first, locked position defines a first valve lift mode and the second, unlocked position defines a second valve lift mode.

7. The switchable finger follower of claim 6 , wherein the first valve lift mode is a full valve lift mode and the second valve lift mode is a no valve lift mode.

8. The switchable finger follower of claim 6 , wherein the first valve lift mode is a high valve lift mode and the second valve lift mode is a low valve lift mode.

9. The switchable finger follower of claim 1 , wherein the second locking surface is located on the inner lever and the coupling pin bore is located on the outer lever.

10. The switchable finger follower of claim 1 , further comprising a valve interface configured on the first outer lever end.

11. A valve train for an internal combustion engine, comprising:
a camshaft with a cam;
an engine valve;
a hydraulic pivot element; and
a switchable finger follower located between the camshaft and the engine valve, the switchable finger follower comprising
an inner lever having first and second inner lever ends, a sliding pad located between the first and second inner lever ends, the sliding pad having at least one of an anti-friction coating or a surface finish of Ra 0.05 or better forming a cam contact surface on which the cam rides, the inner lever having an I-beam shaped cross-section in an area of the sliding pad, defining two pockets in the inner lever;
an outer lever having two outer arms that extend along longitudinal sides of the inner lever, and a first outer lever end mounted for pivoting movement at the first end of the inner lever by a pivot axle;
a coupling pin arranged to move longitudinally within a coupling pin bore located on one of the inner lever or the outer lever on an end opposite from the pivot axle, the coupling pin having a coupling projection with a first locking surface;
the coupling pin is moveable from a first, locked position with the first locking surface engaged with a second locking surface located on the other of the inner lever or the outer lever, to a second, unlocked position where the first locking surface is not engaged with the second locking surface; and
a lost motion element arranged between the inner lever and the outer lever.

12. The valve train of claim 11 , wherein the sliding pad includes the anti-friction coating which comprises a DLC coating.

13. The valve train of claim 11 , wherein the first outer lever end contacts a stem of the valve.

14. The valve train of claim 11 , wherein a second outer lever end is supported on the hydraulic pivot element.

15. The valve train of claim 11 , wherein a height of the inner lever in an area of the sliding pad is in a range of 30% to 50% of a radius of curvature of the sliding pad.

16. The valve train of claim 15 , wherein the height of the inner lever in the area of the sliding pad is in a range of 45%-50% of the radius of curvature of the sliding pad.

17. The valve train of claim 11 , wherein a combined width of the pockets (2*Wp) is at least 4 times a thickness of a web of the I-beam shaped cross-section.

Assignees

• Schaeffler Technologies Ag

Inventors

• Foster Colin
• Ahmed Faheem

Classifications

• F01L2001/186

  Split rocking arms, e.g. rocker arms having two articulated parts and means for varying the relative position of these parts or for selectively connecting the parts to move in unison · CPC title

• F01L1/053

  overhead type · CPC title

• F01L13/0005

  Deactivating valves · CPC title

• F01L2820/01

  Absolute values · CPC title

• F01L2001/467

  Lost motion springs · CPC title