Internal-combustion engines – Poppet valve operating mechanism – With means for varying timing
Reexamination Certificate
1999-12-28
2001-07-24
Lo, Weilun (Department: 3748)
Internal-combustion engines
Poppet valve operating mechanism
With means for varying timing
C123S090340, C123S090380, C123S1960CP, C123S1960CP, C184S006500
Reexamination Certificate
active
06263844
ABSTRACT:
FIELD OF THE INVENTION
This invention relates-to an oil passage for an internal combustion engine and, more particularly, to an oil passage for an internal combustion engine in which the oil passage is not provided in components such as a cylinder block or a cylinder head as produced by large-scaled facilities, but is provided using components fabricated by small-scaled facilities or small-sized components, and thus manufacturing facilities can be changed at small costs when an existing internal combustion engine is utilized so as to meet technical specifications requiring a different or variable valve timing actuator, whereby a low cost internal combustion engine designed for the valve timing actuator is achievable.
BACKGROUND OF THE INVENTION
An oil passage provided in an internal combustion engine is classed as an oil passage adapted for lubrication and cooling, an oil passage designed for drive, and the like. The former passage supplies engine oil from an oil pan to lubricated sections by an oil pump drawing the engine oil upward from the oil pan. The latter oil passage supplies the engine oil as drive pressure to a variable valve timing actuator. The actuator is disposed on one side of a camshaft.
The oil passage designed for drive is communicated to a main oil gallery of the engine in order to permit the engine oil in the main gallery to be guided into the actuator, thereby adjusting valve timing toward spark advance or delay.
One such example of an oil passage is disclosed in published Japanese Patent Application Laid-Open No. 5-288022. In a device for supplying working oil to a variable valve timing mechanism for an engine as disclosed therein, the working oil is supplied to the mechanism through an oil passage in a camshaft from one of the journal portions of the camshaft, which journal portion is positioned between a journal portion at an end of the camshaft and a central portion of the camshaft in an axial direction thereof. The device supplies the working oil to the variable valve timing mechanism in a stable manner, and the mechanism thereby provides improved response.
Another example of the oil passage is disclosed in published Japanese Patent Application Laid-Open No. 6-159020. In a valve timing adjuster as disclosed therein, even when communication between a source of oil pressure and first and second annular grooves is cut off, oil from a journal-lubricating passage permits lubrication between a cam journal portion and a bearing portion to be always retained in a good condition. In addition, the oil leaking from the journal-lubricating passage is supplied substantially evenly to the first and second annular grooves. As a result, the valve timing adjuster is always actuated in an invariable manner.
A further example of the oil passage is disclosed in published Japanese Patent Application Laid-Open No. 6-317113. In a valve-driving mechanism for an engine as disclosed therein, a cylinder head is formed with a head-side hydraulic passage for communicating an opening of an in-shaft hydraulic passage with a block-side hydraulic passage. The block-side hydraulic passage is formed in a cylinder block. In addition, there is formed a lubricating oil passage that is communicated to a journal portion. The lubricating oil passage is branched off from the head-side hydraulic passage. Further, the head-side hydraulic passage has a changeover valve provided at the branch portion thereof, but displaced toward the journal portion. The changeover valve interrupts a supply of hydraulic pressure. As a result, there is provided improved response to switching of valve timing.
A yet further example of the oil passage is disclosed in published Japanese Patent Application Laid-Open No. 7-166831. In a camshaft-lubricating device for an internal combustion engine as disclosed therein, there are provided a lubricating oil supply hole and a branch passage in order to reliably lubricate respective camshaft bearing surfaces, thereby preventing seizing thereof. The lubricating oil supply hole is communicated to a main oil gallery in a cylinder head. In addition, the supply hole is open to a surface where a camshaft bearing portion and a cam bracket are jointed together. The branch passage is formed along the joint surface between the camshaft bearing portion and the cam bracket. In addition, a distal end of the branch passage is bifurcated so as to be open to the opposite camshaft bearing surfaces, with a peripheral groove being sandwiched therebetween. Further, the branch passage is communicated to the lubricating oil supply hole. The camshaft bearing surfaces are two surfaces divided by the peripheral groove that is formed in a cam journal.
Still another example of the oil passage is disclosed in published Japanese Patent Application Laid-Open No. 9-170415. In an oil passage structure for an internal combustion engine as disclosed therein, an oil passage is laid out compactly in a small space without any changes in position and size of a cam cap bolt.
A yet further example of the oil passage is disclosed in published Japanese Patent Application Laid-Out No. 9-170416. In an oil passage structure for an internal combustion engine as disclosed therein, one oil passage designed for control and another designed for lubrication are rationally arranged in order to form a compact internal combustion engine having a reduced transverse width and a reduced entire length.
Another example of the oil passage is disclosed in published Japanese Patent Application Laid-Open No. 9-222008. In an engine having a lubrication device provided therein as disclosed therein, oil is supplied to first and second tensioners branched off from a main gallery, independently of a system of oil supply to a valve-driving mechanism. There is provided a reduced length of oil supply, which reaches a bearing portion of the second tensioner. In particular, when the engine is started up, there is provided improved response of oil supply to the bearing portions of the second tensioner. In addition, a simplified path of oil supply is provided.
A further example of the oil passage is disclosed in published Japanese Patent Application Laid-Open No. 9-280014. In a valve-driving camshaft structure as disclosed therein, a camshaft has an oil hole provided therein along the axis of the camshaft at a portion extending between a distal end of a bolt and a threaded portion of the bolt. An elongated bore portion is provided at the distal end of the bolt. The elongated bore portion corresponds to the above oil hole. A space between the elongated bore portion and an inner wall of the oil hole of the camshaft is formed as one oil passage. In addition, an intermediate hole provided at a central portion of the bolt along the axis of the bolt is formed as another oil passage. Thus, a compact structure with improved strength is realized.
A still further example of the oil passage is disclosed in published Japanese Patent Application Laid-Open No. 10-8987. In a chain cover structure for a four-cycle engine as disclosed therein, the entire chain cover is formed as a member separate from a cylinder head. The chain cover is formed integrally with a mounting portion, on which an oil supply portion for a valve timing variable device is mounted. As a result, improved operability is obtained when a chain guide and the like is built on the chain cover.
A yet further example of the oil passage is disclosed in published Japanese Patent Application Laid-Open No. 10-8988. In a four-cycle engine having a variable valve timing device as disclosed therein, the variable valve timing device is disposed on one camshaft for changing phase angle between a cam sprocket and the other camshaft in response to a variation in hydraulic pressure that acts on an oil housing body through an oil control solenoid valve. The oil housing body attached to the aforesaid one camshaft is positioned outward in the direction of the camshaft from a primary sprocket of the other camshaft. One of intake-side valve timing and exhaust-side valve timing is independently controllable. A spacing
Kondo Kentaro
Ozeki Hisashi
Flynn ,Thiel, Boutell & Tanis, P.C.
Lo Weilun
Suzuki Motor Corporation
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