Piezoelectric actuator

A piezoelectric actuator for actuating valves, having an actuator body (1) in the form of a multilayered laminate made up of stacked layers of piezoelectric material with intervening electrically conductive layers (27) that function as electrodes, and the end faces of this actuator body (1) are respectively contacted by a top plate (2) oriented toward the valve having an axially protruding valve tappet (3) and a bottom plate (4) at the opposite end, wherein the actuator (10) rests in an axial bore (16) of a valve housing (6), and is prestressed at the ends in the axial direction between the top plate (2) and the bottom plate (4) by means of a spring element (5), wherein at least part of the actuator (10) is enclosed by an electrically insulating sleeve (9, 19;

• 18) made of a ductile, polymer material so that when installed, the actuator (10) with the insulating sleeve (9, 19;
• 18) rests snugly against the inner wall of the axial bore (16) of the valve housing (6) in the vicinity of the actuator (10), wherein the sleeve (9) includes air bubbles (11).

A piezoelectric actuator for actuating valves, having an actuator body (1) in the form of a multilayered laminate made up of stacked layers of piezoelectric material with intervening electrically conductive layers (27) that function as electrodes, and the end faces of this actuator body (1) are respectively contacted by a top plate (2) oriented toward the valve having an axially protruding valve tappet (3) and a bottom plate (4) at the opposite end, wherein the actuator (10) rests in an axial bore (16) of a valve housing (6), and is prestressed at the ends in the axial direction between the top plate (2) and the bottom plate (4) by means of a spring element (5), wherein at least part of the actuator (10) is enclosed by an electrically insulating sleeve (9, 19;

• 18) made of a ductile, polymer material so that when installed, the actuator (10) with the insulating sleeve (9, 19;
• 18) rests snugly against the inner wall of the axial bore (16) of the valve housing (6) in the vicinity of the actuator (10), wherein before insertion into the axial bore (16), the sleeve (9, 19) has a convexity (20) whose diameter (D), at least in sections, is greater than the inner diameter (d) of the axial bore (16) of the valve housing (6), and wherein the sleeve (9) includes air bubbles (11).

A piezoelectric actuator for actuating valves, having an actuator body (1) in the form of a multilayered laminate made up of stacked layers of piezoelectric material with intervening electrically conductive layers (27) that function as electrodes, and the end faces of this actuator body (1) are respectively contacted by a top plate (2) oriented toward the valve having an axially protruding valve tappet (3) and a bottom plate (4) at the opposite end, wherein the actuator (10) rests in an axial bore (16) of a valve housing (6), and is prestressed at the ends in the axial direction between the top plate (2) and the bottom plate (4) by means of a spring element (5), wherein at least part of the actuator (10) is enclosed by an electrically insulating sleeve (9, 19;

• 18) made of a ductile, polymer material so that when installed, the actuator (10) with the insulating sleeve (9, 19;
• 18) rests snugly against the inner wall of the axial bore (16) of the valve housing (6) in the vicinity of the actuator (10), wherein the outer contour of the sleeve (9) has grooves (12) at definite locations.

A piezoelectric actuator for actuating valves, having an actuator body (1) in the form of a multilayered laminate made up of stacked layers of piezoelectric material with intervening electrically conductive layers (27) that function as electrodes, and the end faces of this actuator body (1) are respectively contacted by a top plate (2) oriented toward the valve having an axially protruding valve tappet (3) and a bottom plate (4) at the opposite end, wherein the actuator (10) rests in an axial bore (16) of a valve housing (6), and is prestressed at the ends in the axial direction between the top plate (2) and the bottom plate (4) by means of a spring element (5), wherein at least part of the actuator (10) is enclosed by an electrically insulating sleeve (9, 19;

• 18) made of a ductile, polymer material so that when installed, the actuator (10) with the insulating sleeve (9, 19;
• 18) rests snugly against the inner wall of the axial bore (16) of the valve housing (6) in the vicinity of the actuator (10), wherein before insertion into the axial bore (16), the sleeve (9, 19) has a convexity (20) whose diameter (D), at least in sections, is greater than the inner diameter (d) of the axial bore (16) of the valve housing (6), and wherein the outer contour of the sleeve (9) has grooves (12) at definite locations.