Electrical generator or motor structure – Non-dynamoelectric – Piezoelectric elements and devices
Reexamination Certificate
2001-02-07
2002-12-17
Ramirez, Nestor (Department: 2834)
Electrical generator or motor structure
Non-dynamoelectric
Piezoelectric elements and devices
C310S348000, C310S366000
Reexamination Certificate
active
06495946
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a piezoelectric actuator, for example for actuating a mechanical component, such as a valve or the like, comprising a piezoelectric element, which is provided with a multi-layer structure of piezoelectric layers with internal electrodes disposed between them and with external electrodes making electrical contact with the internal electrodes on alternate sides.
It is generally known that a piezoelectric element operating according to the piezoelectric effect can be constructed out of a material with a suitable crystalline structure. The application of an external electrical voltage causes a mechanical reaction of the piezoelectric element which, depending on the crystalline structure and the region to which the electrical voltage is applied, produces a compression or tension in a predictable direction.
The piezoelectric actuators mentioned above are frequently used in valve positioning. Among other things, their stroke capacity for actuating a valve tappet, for example, is relatively small and thermal expansion of the ceramic of the piezoelectric element can lead to a drift in the position of the valve tappet when the piezoelectric element is not triggered. Also, contact with the active parts of the piezoelectric actuator is difficult.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a piezoelectric actuator, which does not suffer from the above-described disadvantages.
The piezoelectric actuator described at the beginning, which can be used, for example, to actuate a mechanical component, advantageously has a piezoelectric element that generates a tensile or compressive force acting on an actuation element, which is provided with a multi-layer structure of piezoelectric layers with internal electrodes disposed between them and with external electrodes contacting the internal electrodes on alternate sides of the piezoelectric element.
In this connection, it is particularly advantageous that the external electrical connections for the lateral contacting are affixed to an inactive end region in the layer structure and the end region has a core with favorable heat conductivity. As a result, the external contacting of the piezoelectric actuator in inactive end regions that are not affected by tensile or compressive forces, which contacting must be reliably produced, can be easily combined with favorable heat dissipation in order to avoid the disadvantages described at the beginning.
In one advantageous embodiment, the inactive end region has a relatively thin, electrically insulating cover layer on the layer structure. The cover layer is provided with a heat-conducting core which in turn has electrically insulating ceramic layers affixed to its sides. The connection between the external electrodes and the external electrical connections can thereby be produced in the ceramic layers. Preferably this can be achieved by means of a solder layer which is applied to the respective ceramic layer in the vicinity of the external electrodes. In another likewise very advantageous embodiment, the inactive end region comprises an electrically insulating ceramic part in which the connection between the external electrodes and the external electrical connections can be produced at the sides. In this embodiment. a heat-conducting core is embedded in the ceramic layer. In a particularly preferable way, in the plane of the layers, the core has a round contour and is consequently disk-shaped on the whole.
These and other features of preferred improvements of the invention ensue from the claims, the specification, and the drawings, wherein the individual features can be realized singly or multiply in the form of sub-combinations in the various embodiments of the invention and in other areas and can represent advantageous and intrinsically patentable embodiments which are claimed herein.
REFERENCES:
patent: 4166967 (1979-09-01), Benes et al.
patent: 4633120 (1986-12-01), Sato et al.
patent: 4780639 (1988-10-01), Shirasu
patent: 4803763 (1989-02-01), Eturo et al.
patent: 4845399 (1989-07-01), Yasuda et al.
patent: 5089739 (1992-02-01), Takahashi et al.
patent: 5237239 (1993-08-01), Inoue et al.
patent: 5266862 (1993-11-01), Ohya
patent: 5438232 (1995-08-01), Inoue et al.
patent: 5629906 (1997-05-01), Sudol et al.
patent: 5644184 (1997-07-01), Kucherov
patent: 5847490 (1998-12-01), Kumasaka et al.
patent: 6131256 (2000-10-01), Dydyk et al.
patent: 6262518 (2001-07-01), Ishikawa et al.
patent: 6266857 (2001-07-01), Corbett, III et al.
patent: 6291929 (2001-09-01), Heinz et al.
patent: 6310422 (2001-10-01), Satoh et al.
patent: 6333587 (2001-12-01), Heinz et al.
patent: 6392327 (2002-05-01), Lewis et al.
patent: 02017873 (1990-01-01), None
patent: 02017875 (1990-01-01), None
patent: 02083424 (1990-03-01), None
patent: 02083425 (1990-03-01), None
patent: 03020673 (1991-01-01), None
patent: 05335875 (1993-12-01), None
Patent Abstract of Japan vol. 1995, No. 07, Aug. 31, 1995 & JP 07 099347 A, Apr. 11, 1995.
Boecking Friedrich
Heinz Rudolf
Sugg Bertram
Cuevas Pedro J.
Ramirez Nestor
Robert & Bosch GmbH
Striker Michael J.
LandOfFree
Piezoelectric actuator for positioning with heat dissipating... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Piezoelectric actuator for positioning with heat dissipating..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Piezoelectric actuator for positioning with heat dissipating... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2986359