| 摘要 |
The invention concerns an actuator comprising a sliding sleeve (1) and a piston (2) axially mobile in said sleeve, said piston comprising a plurality of piezoelectric sections made of multilayer material, control means for applying on said sections control voltages for expanding said sections so that they are locked relative to the sliding sleeve and extend other sections inside said sleeve, said expansions and extensions being controlled by said control means according to the sequences moving the piston in said sleeve. The invention is characterised in that the control means are capable of applying to each of the sections a voltage which shortens said section and locks it in the sliding sleeve and an inverse voltage which releases said section relative to said sleeve and extends it therein, one and the other of said voltages being applied successively to said section during a sequence displacing the piston, each section being thus used both for locking and extending during such a sequence.
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