To provide a gear pump capable of eliminating sudden pressure change when fluid retained in a void part between teeth changes from suction pressure to delivery pressure.
This gear pump includes a pair of gears mutually meshing, a cylinder block 11 having a gear storage chamber 16 storing both gears formed thereon, and a cover covering the gear storage chamber 16. A sliding contact surface 20f sliding and contacting on a gear flank perpendicular to rotation axes of the gears 30, 40 is formed on side plates 19, 20 put between the cover and the gear side surface, or on the cover. The gears are sealed by the sliding contact surface 20f after retaining fluid at suction pressure. The void part 35 between teeth communicating to a delivery area by rotation of the gears is included. An introduction groove 20g is formed in the sliding contact surface 20f. One end of the introduction groove 20g is communicated to a delivery pressure area and another end of the introduction groove 20g is established at a position communicating to the void part 35 between teeth almost sealed by the sliding contact surface 20f.
COPYRIGHT: (C)2007,JPO&INPIT
OTA MASAKI
MURAKAMI KAZURO
YAMASHITA KATSUMI
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