Patent ID: 6652253
Filing Date: 2003-11-25
Classification: F04C

Abstract:
An internal/external gear pump comprising:an externally toothed gear member; an internally toothed gear member; an inlet port admitting fluid to said pump; an outlet port discharging fluid from said pump at an elevated pressure; said toothed gear members having a mesh area wherein the external and internal teeth enter into and retract from an intermeshing relationship, said internally toothed gear member and said externally toothed gear member having a full mesh position between said inlet port and said outlet port within the mesh area wherein one tooth of the externally toothed member is fully meshed in a space between two teeth of said internally toothed gear member defining a volume of trapped fluid; one side of said full mesh position axially defining an inlet portion of said pump and another side of said full mesh position defining a pressure portion of said pump; a sidewall disposed adjacent said gear members defining one closure wall for said pump; and a recess formed in said sidewall extending from said inlet port to a leading edge of said trapped volume in said full mesh position to establish a restricted flow path between said volume of trapped fluid and said inlet port.