Oil pump rotor

An oil pump emits less noise by properly forming the profiles of teeth of an inner rotor and an outer rotor thereof which engage each other, whereby decreasing sliding resistance and rattle between the tooth surfaces of the rotors. The rotors of the oil pump are formed so the inner rotor having &quo...

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Bibliographic Details
Main Author Hosono, Katsuaki
Format Patent
LanguageEnglish
Published 03.05.2005
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Summary:An oil pump emits less noise by properly forming the profiles of teeth of an inner rotor and an outer rotor thereof which engage each other, whereby decreasing sliding resistance and rattle between the tooth surfaces of the rotors. The rotors of the oil pump are formed so the inner rotor having "n" teeth is formed such that the tooth tip profile and tooth space profile thereof are formed using cycloid curves which are formed by rolling a first circumscribed-rolling circle and a first inscribed-rolling circle along a base circle, respectively, and the outer rotor having "n+1" teeth is formed such that the tooth tip profile and tooth space profile thereof are formed using cycloid curves which are formed by rolling a second circumscribed-rolling circle and a second inscribed-rolling circle along a base circle, respectively, and in such a manner that the following equations are satisfied: øBo=øBi; øDo=øDi·(n+1)/n+t·(n+1)/(n+2); and øAo=øAi+t/(n+2).