To easily incorporate a parking lock device which is small-sized and has large force of constraint in a gerotor motor.
A hydraulic motor has a form including a gerotor gear set 15 having a star member 31 performing track and revolving motion. In this motor, a spool valve 41 is arranged in front of the gerotor gear set 15 and a tip part cap assembly 21 is arranged in the rear. The track and revolving motion of the star member 31 is prevented by energizing a lock piston 75 within the tip part cap assembly 21 by conical springs 85, 87 and engaging an inclined part 91 of the lock piston 75 to an opening 31 of the star member 31. Pressure fluid is introduced into a pressure chamber 99 from a pressure port 93, the lock piston 75 is retreated against energizing force of the conical springs 85, 87 by this pressure, the engagement of the opening 31 and the inclined part 91 is released and the track and revolving motion of the star member 31 is allowed.
KASSEN GARY ROGER
YAKIMOW SCOTT EDWARD
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