Patent ID: 7559754
Filing Date: 2009-07-14
Classification: F01M,F02B,F04C,F05C

Abstract:
1. An internal gear pump assembly in a combustion engine for supplying a lubricant oil to the combustion engine, which pump comprises: an inner rotor relatively non-rotatably mounted on one end of a pump shaft driven by a crankshaft; and an outer rotor rotatably supported by a crankcase and meshed with the inner rotor; said pump shaft being formed by a lower end portion of a vertical camshaft and having a flange formed integrally therein, the flange being rotatably supported by the crankcase and covering one end face of each of the inner and outer rotors; wherein the flange is rotatably engaged directly in a shaft receiving hole defined in the crankcase, said flange directly engaged in the shaft receiving hole without an axial bearing support member intervening between the flange and the shaft receiving hole, wherein the flange and the shaft receiving hole together define a plain bearing therebetween; wherein the camshaft is formed integrally with the flange and a pump drive shaft protruding along the axis of rotation of the camshaft and on the opposite side of the flange from the camshaft, wherein the pump drive shaft is directly engaged in a center hole defined by the inner rotor without a radial bearing support member between the flange and an end of the pump drive shaft; wherein the crankcase has a top opening and a bottom surface formed integrally with an oil pan accommodating a lubricant oil, and the bottom surface of the crankcase is formed with the shaft receiving hole, a pump chamber positioned below the shaft receiving hole, and suction and discharge ports positioned below the pump chamber and fluidly connected with the pump chamber, the pump chamber having a diameter smaller than that of the shaft receiving hole and accommodating the inner rotor and the outer rotor; and further comprising: a cam gear fixedly mounted on the camshaft and toothedly engaged with the crankshaft to drive the camshaft; a cam defined in the cam shaft between the flange and the cam gear; and an oil supply passage for supplying the lubricant oil from the internal gear pump onto the cam gear, wherein the cam gear is fixedly mounted on an upper end portion of the camshaft immediately adjacent a distal end of the camshaft.