Oil supply structure for reducing friction of cam shaft

Abstract

An oil supply structure for reducing friction of a cam shaft attached to a valve train of an automotive engine is disclosed. An oil supply hole formed in a cam shaft is, repeatedly connected and disconnected to a cylinder head oil supply hole during the rotation of the cam shaft. An oil pocket is established in the form of a concave groove in a section in the circumferential direction on an inner circumferential surface of a cam cap assembled on the top of the cam shaft so as to supply oil to the oil pocket only when the cylinder head oil supply hole is connected to the cam shaft oil supply hole. It is thus possible to supply oil to the oil pocket through the cam shaft oil supply hole at specific points of time and, simultaneously, to sufficiently ensure the sealing width in other regions than the oil pocket, thus reducing oil loss and obtaining a more efficient friction reduction.

Description

[0001] Cross References to Related Applications [0002] This application is based on and claims priority from Korean Application No. 10-2006-0112093 filed on November 14, 2006, the entire disclosure of which is incorporated herein by reference. technical field [0003] The invention relates to an oil supply structure for reducing camshaft friction, and more particularly relates to an oil supply structure fixed on a valve mechanism of an internal combustion engine. Background technique [0004] Generally, each cylinder of a vehicle engine includes at least two valves divided into an intake valve and an exhaust valve. The intake valve opens just before the intake stroke to let the mixture of gas and fuel enter the cylinder, and the exhaust valve opens just before the exhaust stroke to let the combustion exhaust out of the cylinder. [0005] The valves are operated by a valve train configured to open and close the intake and exhaust valves at precise points in time through th...

AI Technical Summary

Problems solved by technology

However, conventional oil supply structures have some drawbacks

[0009] First, since oil usually enters the camshaft through the hollow flow passage, the external structure for supplying oil to the hollow flow passage of the camshaft is very complicated. So there are many limitations in the design

[0010] Second, when a typical conventional structure is applied to a small engine, oil pressure may be lowered to impair friction reduction performance, and the hollow camshaft provided thereon may also become a factor that increases production cost

[0011] Thirdly, since the amount of lubricating oil supplied to the oil groove of the conventional structure is too large, the amount of lubricating oil discharged to the outside through the oil groove is also too large, thus consuming a large amount of lubricating oil unnecessarily

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