Patent ID: 6234776
Filing Date: 2001-05-22
Classification: F01C,F04C

Abstract:
A vane pump, comprising:a cam ring comprising a rotor joined to a drive shaft, and vanes provided in said rotor such that they are free to move in or out,a body supporting said drive shaft and housing said cam ring,a side plate on which are symmetrically provided first low pressure ports corresponding to an intake area of said cam ring and a high pressure port corresponding to a discharge area and connected to a high pressure chamber in said body,an intake chamber formed between an inner circumference of said body and an upper outer circumference of said cam ring, said intake chamber connecting with a low pressure passage for leading hydraulic fluid from the outside,a branch passage formed between said inner circumference of said body and said upper outer circumference of said cam ring connecting said first low pressure ports of said side plate with said intake chamber,a cover comprising an end face joined to an open end face of said body which comes in contact with one end face of said cam ring, wherein second low pressure ports are symmetrically arranged as depressions at positions corresponding to said intake area of said cam ring, and a low pressure distributing groove provided as a depression connected to said intake chamber which splits into two along said upper outer circumference of said cam ring towards said second low pressure ports, anda pin implanted in said side plate whereof a tip extends by a predetermined amount from said open end face of said body towards said cover, whereina throughhole is formed in said cam ring through which said pin passes,a concave part of predetermined depth is formed in said cover which engages with said tip of said pin, andan escape hole of predetermined depth for housing a tip end of said drive shaft is formed in said end face of said cover at a position corresponding to said drive shaft.