GEAR PUMP AND METHOD OF MANUFACTURING INNER ROTOR

摘要

PROBLEM TO BE SOLVED: To provide a gear pump for improving its discharge performance by making teeth higher while suppressing an increase in the size and a reduction in the number of teeth, and for achieving adequate clearances between each of external teeth of an inner rotor and each of internal teeth of an outer rotor.SOLUTION: Each of external teeth 20 of an inner rotor 2 includes a tooth top part 21 formed by an epitrochoid curve which is obtained by non-slidably rolling an external rolling circle Co while circumscribing it on a base circle BC and whose trochoid coefficient is larger than a value of 1, a tooth bottom part 22 formed by a hypotrochoid curve which is obtained by non-slidably rolling an internal rolling circle Ci while inscribing it on the base circle BC and whose trochoid coefficient is larger than a value of 1, and an intermediate part 23 formed by an involute curve and located between the tooth top part 21 and the tooth bottom part 22.