Precision control of linear movement - using electrically controlled contact surfaces of tubular piezoelectric element to exercise selective clamping effect on axle

摘要

The axle to be linearly moved (1) is concentrically surrounded by a tubular piezo-electric transducer element (2) having contact surfaces on its inner and outer sheath surface. One of the contact surfaces is divided into at least three contact sections (4,5,6). These can be independently electrically controlled by separate leads (U1,U2,U3). The change of inner dia. in the element (2) arising from initiated control of a contact section has a magnitude corresponding to a change between a press fit and a fitting with play between the transducer (2) and the axle (1). An elastic and incompressible material is pref. inserted between the element (2) and the axle (1) and having a high coefft. of friction w.r.t. the latter (1). This arrangement is suitable for a controllable linear motor, esp. for slow movements of extreme accuracy since reduction gearing, spindle etc. tolerances are obviated.