The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 17, 1984
Filed:
Jan. 28, 1981
Johann Merz, Bopfingen, DE;
Zahnradfabrik Friedrichshafen, AG, Friedrichshafen, DE;
Abstract
A gear pump having an annular internal tooth gear and an external tooth gear eccentrically rotative therein is provided with a choke bore at the inlet side of the pump and a series of outlet pressure bores. The outlet bores are valved with individual check valves so as to pass pressure oil from the pressure pockets between the relatively moving gear teeth which pockets diminish in volume at the outlet side of the pump as the teeth move therepast and the pressure pockets discharge into the outlet bores. Where a pocket is insufficiently filled to effect the pressure needed for opening the first valves moved pass by the pressure pockets, the pressure increases with continued rotation as pocket volume decreases. The increase in pressure in the pockets with volume reduction ultimately opens an outlet bore valve to effect discharge to a common high pressure chamber. Thus, when pump speed is increased, a reduction in inlet suction fails to fully fill the pockets at the inlet zone and the valving arrangement prevents short circuit of flow or back feed from the high pressure common outlet chamber to partially filled pressure pockets at the inlet side causing a recirculation and energy loss. Such partially filled pockets will ultimately discharge as they are reduced in size to force out the oil therein at a valve opening pressure. Provision is made to prevent flow between adjoining pressure pockets.