Piezoelectric actuator

Claim 2

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 ).

Claim 3

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 ).

Claim 4

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 ).

Claim 5

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.

Claim 6

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.

Claim 7

The piezoelectric actuator according to claim 3 , wherein the grooves ( 12 ) are embodied as annular grooves.

Claim 8

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.

Claim 9

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.

Claim 10

The piezoelectric actuator according to claim 5 , wherein the grooves ( 12 ) are embodied as annular grooves.

Claim 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 at least one radial centering ring ( 15 , 15 a ), made of a material which is stronger than the rest of the sleeve, encompasses the actuator body ( 1 ), wherein the inner contour of the centering ring ( 15 , 15 a ) is adapted to the outer contour of the actuator body ( 1 ) and the outer contour of the centering ring ( 15 , 15 a ) is adapted to the inner contour of the axial bore ( 16 ) of the valve housing ( 6 ).

Claim 12

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 at least one radial centering ring ( 15 , 15 a ), made of a material which is stronger than the rest of the sleeve, encompasses the actuator body ( 1 ), wherein the inner contour of the centering ring ( 15 , 15 a ) is adapted to the outer contour of the actuator body ( 1 ) and the outer contour of the centering ring ( 15 , 15 a ) is adapted to the inner contour of the axial bore ( 16 ) of the valve housing ( 6 ).

Claim 13

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 at least one radial centering ring ( 15 , 15 a ), made of a material which is stronger than the rest of the sleeve, encompasses the actuator body ( 1 ), wherein the inner contour of the centering ring ( 15 , 15 a ) is adapted to the outer contour of the actuator body ( 1 ) and the outer contour of the centering ring ( 15 , 15 a ) is adapted to the inner contour of the axial bore ( 16 ) of the valve housing ( 6 ).

Claim 14

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 at least one radial centering ring ( 15 , 15 a ), made of a material which is stronger than the rest of the sleeve, encompasses the actuator body ( 1 ), wherein the inner contour of the centering ring ( 15 , 15 a ) is adapted to the outer contour of the actuator body ( 1 ) and the outer contour of the centering ring ( 15 , 15 a ) is adapted to the inner contour of the axial bore ( 16 ) of the valve housing ( 6 ).