INSCRIPTION GEAR TYPE EXPANDER

摘要

PROBLEM TO BE SOLVED: To provide a high performance inscription gear type expander in which a loss by leakage of working fluid is restricted.SOLUTION: An expander 1 of this invention comprises a first cover 40 arranged at one axial end side of a rotor chamber 2 formed between the rotors 10 and 20 and having a suction port 42 and a discharging port 43 toward the one end side; and a second cover 50 arranged at the other axial end side of the rotor chamber 2. The second cover 50 comprises a fixed part 51 having a pressure chamber 542 arranged therein; and a movable plate 52 formed with an aeration hole 52c communicating with the rotor chamber 2 and the pressure chamber 542 and formed with a counter-port 56. The counter-port 56 has first and second ports 561, 562 forming shapes corresponding to the suction port 42 and the discharging port 43. The first and second ports 561, 562 are arranged at positions facing against the suction port 42 and discharging port 43 while holding the rotor chamber 2 therebetween. Working fluid in the pressure chamber 542 can generate force F for pushing back the movable plate 52 toward the first cover 40.