| 摘要 |
PROBLEM TO BE SOLVED: To suppress wear caused by back pressure acting on a clearance between a rotating member and a casing.SOLUTION: A pump device 48 includes: a third lid member 28; a pump chamber 32 and a rotor 50 in a casing 30; a pinion 52; and a rotary shaft 53. The third lid member 28 is fastened to a side of the casing 30 by means of three mounting bolts 29 and occludes the pump chamber 32. An end face 52b on a third lid member 28 side receives discharge pressure of the discharge port 32b during pump operation, and thus liquid-gas pressure acts as back pressure on a clearance between the rotor 50 and an inner surface of the pump chamber 32. Thus, while the pinion 52 is pressed in a direction to slidingly contact a wall surface 26a of an inner wall 26 of the third lid member 28, the end face 52b is pressed in a direction to be spaced apart from the wall surface 26a of the inner wall 26 of the third lid member 28, by the discharge pressure of the discharge port 32b introduced from a pressure introduction hole 27 into an annular recessed portion 24. |
