Hydraulic gear pump

US4850814A · kind A · utility

Assignee

• Barmag AG · DE

Inventors

• Siegfried Hertell · Radevormwald, DE
• Dieter Otto · Achern, DE

Key dates

• Filing date: Nov 9, 1987
• Grant date: Jul 25, 1989
• Expiry date: Nov 9, 2007

Classification

• Technology area (CPC F): Mechanical Engineering; Lighting; Heating
• CPC primary: F04B49/22
• WIPO field: Engines, pumps, turbines
• WIPO sector: Mechanical engineering

Abstract

A hydraulic gear pump for the oil lubrication system of an automobile engine is disclosed, and wherein the meshing teeth of the gears define fluid cells which are expanded in the intake portion and receive the fluid from an inlet, and then compressed in the discharge portion to expel the fluid. The inlet to the pump includes at least two parallel fluid lines which are each connected to a tank. A pressure controlled valve is connected to one or both of the fluid lines, and during the normal operating range of output pressure, the valve is controlled by the pressure in the pump discharge chamber so as to decrease the flow through the lines from a maximum flow rate to a lower flow rate as the output pressure increases. In the event the engine and oil are cold, the output pressure will increase beyond the normal operating range, since the oil consumption is small. To heat this oil, the valve also includes means for throttling a portion of the output of the pump when the output pressure reaches a predetermined relatively high relief pressure which is greater than the normal operating pressure, and this throttling serves to rapidly increase the temperature of the oil. Also, the inlet flu…