Patent ID: 7488163

Claim:
A trochoid oil pump in which an interdental space constituted by an inner rotor and an outer rotor that meshes with the inner rotor, both the inner rotor and outer rotor having a trochoidal tooth profile or a substantially trochoidal tooth profile which forms a sealed space in a partition section between a trailing end portion of an intake port and a leading end portion of a discharge port or a protruding linking groove formed as a shallow groove from the start portion of the discharge port to the intake port side, wherein a compression stroke in which the interdental space constituting the sealing space in the partition section is moved toward the discharge port side and a volume of the interdental space reduces to form a compressed state and form a state in which the interdental space does not directly open to the discharge port or the protruding linking groove of the discharge port is established, wherein a linking gap variable by a rotation of the rotor such that a width of a relative gap between the tooth profile of the inner rotor and the tooth profile of the outer rotor gradually expands in the compression stroke in the partition section is provided so as to be constituted between the interdental space of the compression stroke in the partition section and a succeeding interdental space already opened and linked to the discharge port or the protruding linking groove of the discharge port, the linking gap causing a fluid to flow between the succeeding interdental space and the interdental space of the compression stroke in the partition section, wherein the operation for expanding the linking gap is maintained to at least a vicinity of a discharge start position of the discharge port of the interdental space of the compression stroke or the protruding linking groove of the discharge port, and wherein the interdental space having passed through the compression stroke opens and links to the discharge port or the protruding linking groove of the discharge port.