Patent ID: 6935297
Filing Date: 2005-08-30
Classification: F01M

Abstract:
1. A lubricating system for a 4-cycle engine in which a side cover defining a first valve-operating chamber is bonded to one side of a crankcase defining a crank chamber which accommodates a crank portion of a crankshaft; a head cover defining a second valve-operating chamber leading to the first valve-operating chamber is bonded to a head portion of a cylinder block connected to the crankcase; and a valve-operating mechanism is accommodated in a region extending from the first valve-operating chamber to the second valve-operating chamber, wherein oil reservoir chambers for storing lubricating oil up to a level higher than a journal portion of the crankshaft are defined by recesses formed in the crankcase and the side cover to surround the crank chamber and the first valve-operating chamber; oil supply passages are provided in the crankshaft to permit a portion of each of the oil reservoir chambers below an oil surface therein to communicate with the crank chamber so that the oil passed through the oil supply passages can be scattered to produce an oil mist the crank chamber is put into communication with the first valve-operating chamber through a one-way valve which is adapted to be opened only when the pressure in the crank chamber is raised; a recovery bore which opens into a bottom of the first valve-operating chamber or the second valve-operating chamber for recovering liquefied oil is put into communication with a portion of each of the oil reservoir chambers above the oil surface; and a breather chamber is put into communication with an upper portion of the second valve-operating chamber.