Adjustment device for use in e.g. hydraulic motor for adjusting delivery volume of motor, has resetting device moving cradle towards neutral position, and return device with valve over which space of cylinder is acted upon with pressure

The device has a swivel cradle (7) adjusted by a control cylinder (4), which is actuated over a steady adjustable position control valve (6). The cylinder is pre-tensioned toward a neutral position, and the swivel cradle occupies the neutral position in the cylinder. A hydraulic resetting device (14) moves the swivel cradle toward the neutral position. A hydraulic return device (16) comprises a return valve (18) over which position spaces (34, 36) of the cylinder are acted upon with actuating pressure in a resetting direction. A closing valve (20) is attached to the return valve. The return valve is designed as a 3/3-way valve and a directional valve. The closing valve is designed as a 2/2 or 4/2-way valve. The control cylinder is designed as a synchronous cylinder. Offenbart sind eine Verstelleinrichtung und eine mit einer derartigen Verstelleinrichtung ausgeführte Axialkolbenmaschine, bei der in einer Notfunktion eine hydraulische Rückstellung eines Stellzylinders erfolgt.