Camshaft thrust bearing lubrication system

Patent metadata

Field	Value
Publication number	US-9797280-B2
Application number	US-201514879644-A
Country	US
Kind code	B2
Filing date	Oct 9, 2015
Priority date	Oct 9, 2015
Publication date	Oct 24, 2017
Grant date	Oct 24, 2017

Abstract

Methods and systems are provided for regulating oil flow to advance and retard chambers of a variable cam timing (VCT) system and to a thrust bearing of a camshaft via an oil control valve. In one example, an oil control valve may be housed within a cam journal cap the cam journal cap comprising a thrust bearing for receiving and retaining a camshaft. The cam journal cap may include a vertical bore configured to house the control valve, where the vertical bore may include a first port for receiving oil from an oil pump, a second port for flowing oil to an advance chamber of a VCT system, a third port for flowing oil to a retard chamber of the VCT system, a fourth port, coupled to the thrust bearing for flowing oil thereto, and a drain port for flowing oil to an oil sump.

First claim

The invention claimed is:

1. A cam journal cap comprising:
a thrust bearing housed by the cam journal cap and coupled to a camshaft;
a vertical bore housing a control valve, the control valve regulating oil received from an oil pump to control a position of the camshaft, wherein the vertical bore is at a right angle with respect to ground when included in an on-road vehicle;
a port positioned in the vertical bore and coupled to the thrust bearing to supply oil thereto;
a drain port positioned in the vertical bore above the port and coupled to an oil sump; and
an inlet port for receiving oil from the oil pump, wherein the inlet port is positioned vertically above the port and drain port.

2. The cam journal cap of claim 1 , further comprising a semicircular recess within a bottom face of the journal cap for covering the camshaft, where the thrust bearing comprises a groove within said semicircular recess.

3. The cam journal cap of claim 1 , wherein the vertical bore forms a housing of the control valve, and where the control valve includes a spool, movable within a body of the control valve for adjusting oil flow through the valve.

4. The cam journal cap of claim 3 , wherein each of the port and the drain port are vertically below a bottom end of the spool and the body of the control valve.

5. The cam journal cap of claim 3 , wherein the control valve includes an opening at a bottom of the valve that drains oil to a bottom of the vertical bore.

6. The cam journal cap of claim 1 , wherein the port and the drain port are disposed at diametrically opposed angular positions.

7. The cam journal cap of claim 1 , wherein the port and the drain port are hydraulically in parallel when oil levels in the vertical bore are greater than a threshold.

8. The cam journal cap of claim 1 , wherein a cross sectional flow area of the port is less than a cross sectional flow area of the drain port.

9. The cam journal cap of claim 1 , wherein oil flows through the drain port only during conditions in which oil levels in the vertical bore are above a threshold.

10. A cam journal cap coupled to a cylinder head of an engine system, the journal cap comprising:
a semicircular recess within a bottom face of the journal cap for covering a camshaft, said semicircular recess including a thrust bearing for accepting a thrust ring of the camshaft; and
a vertical bore within a top face of the journal cap configured to house a control valve for a variable camshaft timing mechanism, wherein the vertical bore is at a right angle with respect to ground when included in an on-road vehicle, said vertical bore including:
a first port to receive oil from an oil pump;
a second port, positioned vertically above the first port, coupled to an advance chamber of the variable timing mechanism;
a third port, positioned vertically below the first port, coupled to a retard chamber of the variable timing mechanism;
a fourth port, positioned vertically below the third port, coupled to the thrust bearing; and
a drain port, positioned vertically between the third port and the fourth port, coupling the vertical bore to an oil sump.

11. The cam journal cap of claim 10 , wherein a bottom of the vertical bore is sealed to collect at least a portion of oil received from the oil pump.

12. The cam journal cap of claim 11 , where an amount of oil collected in the bottom of the vertical bore is always sufficient to submerge the fourth port in oil during engine operation.

13. The cam journal cap of claim 10 , wherein the fourth port and the drain port are hydraulically in parallel when oil levels in the vertical bore exceed a threshold, so that oil flows out of both the fourth port and the drain port when oil levels in the vertical bore exceed the threshold.

14. The cam journal cap of claim 13 , wherein the fourth port and the drain port are positioned in the vertical bore so that oil flows out of the valve through the fourth port and not the drain port when oil levels decrease below the threshold.

15. The cam journal cap of claim 10 , wherein the semicircular recess further includes a groove in fluidic communication with the second port and the advance chamber, for directing oil from the second port to the advance chamber.

16. The cam journal cap of claim 10 , wherein the semicircular recess further includes a groove in fluidic communication with the third port and the retard chamber, for directing oil from the third port to the retard chamber.

17. The cam journal cap of claim 10 , wherein the control valve further comprises a hollow passage for draining oil to a bottom of the vertical bore.

18. The cam journal cap of claim 10 , wherein oil flow through the second and third ports is bidirectional.

19. The cam journal cap of claim 10 , wherein oil flow through the fourth port and the drain port is unidirectional, out of the valve.

20. The cam journal cap of claim 10 , wherein the first port and the fourth port are positioned at a diametrically opposed angular position in the vertical bore relative to the second, third, and drain ports.

21. A method, comprising:
delivering oil to an oil control valve housed in a vertical bore in a cam journal cap of a variable camshaft timing system through an intake port in the vertical bore, wherein the vertical bore is at a right angle with respect to ground when included in an on-road vehicle;
housing a camshaft thrust bearing of the variable camshaft timing system in the cam journal cap;
collecting a portion of the oil in a bottom portion of the vertical bore;
directing a portion of the oil in the bottom portion of the vertical bore through a thrust bearing port in the vertical bore to the camshaft thrust bearing of the variable camshaft timing system; and
flowing a portion of the oil in the bottom portion of the vertical bore through a drain port in the vertical bore to an oil sump when oil levels in the bottom portion of the vertical bore increase above a threshold, wherein the thrust bearing port and the drain port are positioned below the intake port.

22. The method of claim 21 , further comprising adjusting a position of the valve towards a more advanced position and increasing an amount of oil flowing to an advance chamber of the variable cam timing system in response to an advancing of a desired camshaft timing, and adjusting the position of the valve towards a more retarded position and increasing an amount of oil flowing to a retard chamber of the variable cam timing system in response to a retardation of the desired camshaft timing.

Assignees

• Ford Global Tech Llc

Inventors

• Beyer Theodore
• Lacroix Jon Michael
• Patanis Chuck Joseph
• Crowe Jonathan Denis
• Adam Paul John

Classifications

• F01M1/16

  Controlling lubricant pressure or quantity (rendering machines or engines inoperative or idling on lubricant pressure failure F01M1/22) · CPC title

• F01L1/047

  Camshafts · CPC title

• F01L2001/0476

  Camshaft bearings · CPC title

• F01L1/34

  characterised by the provision of means for changing the timing of the valves without changing the duration of opening {and without affecting the magnitude of the valve lift} · CPC title

• F01L9/02

  Mechanical Engineering · mapped topic