Valve actuation system

Patent metadata

Field	Value
Publication number	US-10006317-B2
Application number	US-201514869291-A
Country	US
Kind code	B2
Filing date	Sep 29, 2015
Priority date	Sep 29, 2015
Publication date	Jun 26, 2018
Grant date	Jun 26, 2018

Abstract

A valve actuation system is disclosed for use with an internal combustion engine. The valve actuation system may have a rocker shaft, a rocker arm pivotally mounted on the rocker shaft, at least one cam follower and a pushrod connecting the at least one cam follower to the rocker arm. The valve actuation system may also have a plurality of gas exchange valves, and a bridge connecting the rocker arm to the valves. The valve actuation system may further have at least one spring disposed around each of the valves and configured to bias each of the valves toward closed positions, and a rotocoil configured to rotatably connect the at least one spring to each of the valves. The rotocoil may have an internal chamfer at a bridge end with an angle of about 26-28°. The at least one spring may have an assembled load of about 750-850 N.

First claim

What is claimed is:

1. A valve actuation system, comprising:
a rocker shaft;
a rocker arm pivotally mounted on the rocker shaft and having a first end and a second end;
at least one cam follower;
a pushrod connecting the at least one cam follower to the first end of the rocker arm;
a plurality of gas exchange valves;
a bridge connecting the second end of the rocker arm to the plurality of gas exchange valves;
at least one spring disposed around each of the plurality of gas exchange valves and configured to bias each of the plurality of gas exchange valves toward closed positions; and
a rotocoil configured to rotatably connect the at least one spring to each of the plurality of gas exchange valves, wherein:
the rotocoil has an internal chamfer at a bridge end with an angle of about 26-28° measured relative to a center axis of the rotocoil; and
the at least one spring has an assembled load of about 750-850 N.

2. The valve actuation system of claim 1 , wherein the plurality of gas exchange valves are exhaust valves.

3. The valve actuation system of claim 2 , wherein the internal chamfer of the rotocoil has an angle of about 27.5° relative to the center axis of the rotocoil.

4. The valve actuation system of claim 1 , wherein the at least one spring has an assembled load of about 785 N.

5. The valve actuation system of claim 1 , wherein the at least one spring includes:
an outer spring; and
an inner spring disposed inside the outer spring.

6. The valve actuation system of claim 5 , wherein:
the outer spring has an assembled load of about 500-550 N; and
the inner spring has an assembled load of about 250-300 N.

7. The valve actuation system of claim 1 , further including a stem seal placed over a free portion of a valve guide associated with each of the plurality of gas exchange valves.

8. The valve actuation system of claim 7 , wherein:
the plurality of gas exchange valves are exhaust valves; and
the stem seal is a double gas lip seal.

9. The valve actuation system of claim 1 , wherein:
the plurality of gas exchange valves are exhaust valves; and
a stem diameter of each of the exhaust valves is about 12-13 mm.

10. The valve actuation system of claim 9 , wherein the stem diameter of each of the exhaust valves is about 12.5 mm.

11. The valve actuation system of claim 1 , further including a seat disposed around each of the plurality of gas exchange valves and having a base end, and a sealing surface oriented opposite the base end adjacent a head of each of the plurality of gas exchange valves, wherein:
the base end includes a removal tool engagement surface that tapers conically outward; and
a radial length dimension of the removal tool engagement surface is about 3-4 mm.

12. The valve actuation system of claim 11 , wherein the radial length dimension of the removal tool engagement surface is about 3.4-3.7 mm.

13. The valve actuation system of claim 12 , wherein the seat further includes:
an inner cylindrical surface that joins with the removal tool engagement surface at an intersection; and
a bevel located at the intersection and having an angle of about 28-32° measured relative to a center axis of the seat.

14. The valve actuation system of claim 1 , wherein:
the rotocoil has a spring end located opposite the bridge end; and
the spring end is blunt.

15. The valve actuation system of claim 1 , wherein the rotocoil has an overall axial length of about 15.75-16.25 mm.

16. The valve actuation system of claim 15 , wherein the overall axial length of the rotocoil is about 16 mm.

17. A valve actuation system, comprising:
a rocker shaft;
a rocker arm pivotally mounted on the rocker shaft and having a first end and a second end;
at least one cam follower;
a pushrod connecting the at least one cam follower to the first end of the rocker arm;
a plurality of gas exchange valves;
a bridge connecting the second end of the rocker arm to the plurality of gas exchange valves;
an outer spring disposed around each of the plurality of gas exchange valves and configured to bias each of the plurality of gas exchange valves toward closed positions, the outer spring having an assembled load of about 500-550 N; and
an inner spring disposed inside the outer spring and having an assembled load of about 250-300 N.

18. The valve actuation system of claim 17 , further including a double gas lip seal stem seal placed over a free portion of a valve guide associated with each of the plurality of gas exchange valves.

19. The valve actuation system of claim 18 , wherein:
the plurality of gas exchange valves are exhaust valves; and
a stem diameter of each of the exhaust valves is about 12.5 mm.

20. A valve actuation system, comprising:
a rocker shaft;
a rocker arm pivotally mounted on the rocker shaft and having a first end and a second end;
at least one cam follower;
a pushrod connecting the at least one cam follower to the first end of the rocker arm;
a plurality of gas exchange valves;
a bridge connecting the second end of the rocker arm to the plurality of gas exchange valves;
at least one spring disposed around each of the plurality of gas exchange valves and configured to bias each of the plurality of gas exchange valves toward closed positions;
a rotocoil configured to rotatably connect the at least one spring to each of the plurality of gas exchange valves, the rotocoil having an internal chamfer at a bridge end with an angle of about 27.5° relative to a center axis of the rotocoil; and
a seat disposed around each of the plurality of gas exchange valves and having a base end with a removal tool engagement surface that tapers conically outward, a sealing surface oriented opposite the base end adjacent a head of each of the plurality of gas exchange valves, and an inner cylindrical surface that joins with the removal tool engagement surface at an intersection, wherein:
a radial length dimension of the removal tool engagement surface is about 3.4-3.7 mm; and
a bevel located at the intersection has an angle of about 28-32° measured relative to a center axis of the seat.

Assignees

• Caterpillar Inc

Inventors

• Kizhakkethara Indrajith
• Baskaran Gopinath
• Hattiangadi Ashwin A
• Qu Rong
• Redinbo Kevin W

Classifications

• F01L2305/00

  Valve arrangements comprising rollers · CPC title

• F01L2303/01

  Tools for producing, mounting or adjusting, e.g. some part of the distribution · CPC title

• F01L2001/054

  Camshafts in cylinder block · CPC title

• F01L3/10

  Connecting springs to valve members · CPC title

• F01L3/08

  Valves guides; Sealing of valve stem, e.g. sealing by lubricant · CPC title