Fluid apparatus.

摘要

A fluid apparatus includes a pneumatic cylinder (1) having a main body (2), a piston (3), and a hollow rod (4). A ball screw shaft (6) engaged with a ball nut (5) fixed to the piston (3) is rotatably and axially unmovably mounted in the cylinder (1) and extends in the hollow rod (4). A magnetic brake (7) for braking the ball screw shaft (6) is fixed to an end portion of the main body (2) of the cylinder (1). The number of revolutions of the ball screw shaft (6) is detected and outputted in a signal form by a rotary encoder (8). A primary solenoid controlled valve (13) reciprocates the piston (3) by connecting a pressure source (9) either to a first or second port (P1, P2) of the cylinder (1), and secondary solenoid controlled valves (17, 18) connect a pressure source (14) either to a first braking pressure port (P1 min ) or to a second braking pressure port (P2 min ). A controller (19) outputs a drive signal (S3, S3 min ) for controlling the primary solenoid controlled valve (13), and outputs a primary braking signal (S4, S4 min ) and a secondary braking signal (S5) according to a corresponding operational section (I1,...,In) as well as deviation of the number of revolutions of the ball screw shaft (6) from a target value (V1,...,Vn). The primary braking signal (S4, S4 min ) switches on or off the secondary solenoid controlled valves (18, 17) to apply back pressure to the piston (3), and the secondary braking signal (S5) is for operating the magnetic brake (7).