Abstract: An electric machine includes a rotor, a stator, and an air gap formed between a magnetic device of the rotor and the stator. For the selective setting of the air gap, movement devices implemented by piezoelectric stacks are provided on the rotor and/or on the stator. The movement devices may influence radial positions of the respective magnetic device and thus set the radial air gap width. It is thereby possible to exert open-loop and/or closed-loop control over a power or torque of the electric machine without adjusting stator currents. Vibration or unbalance of the rotor may also be counteracted quickly and effectively during operation of the machine.

Abstract: The disclosure relates to an electric machine and in particular to the monitoring of the electric machine for the presence of a fault, (e.g., in the stator windings). A monitoring unit is provided, wherein the monitoring unit measures the multiphase electrical time signals transmitted from or to the machine and with the aid of a Hilbert filter determines substantially in real time the envelopes and the phase positions of the individual phases of the time signal. The envelopes corresponding to the different phases or the corresponding phase positions are compared with one another by way of forming differences and, in the event that one or more of the differences deviate(s) from a specified expectation value, the presence of a fault is inferred. The approach allows significantly increased operational reliability of the electric machine to be achieved in particular.

Abstract: An electric machine includes a rotor, a stator, and an air gap formed between a magnetic device of the rotor and the stator. For the selective setting of the air gap, movement devices implemented by piezoelectric stacks are provided on the rotor and/or on the stator. The movement devices may influence radial positions of the respective magnetic device and thus set the radial air gap width. It is thereby possible to exert open-loop and/or closed-loop control over a power or torque of the electric machine without adjusting stator currents. Vibration or unbalance of the rotor may also be counteracted quickly and effectively during operation of the machine.

Abstract: The disclosure relates to an electric machine and in particular to the monitoring of the electric machine for the presence of a fault, (e.g., in the stator windings). A monitoring unit is provided, wherein the monitoring unit measures the multiphase electrical time signals transmitted from or to the machine and with the aid of a Hilbert filter determines substantially in real time the envelopes and the phase positions of the individual phases of the time signal. The envelopes corresponding to the different phases or the corresponding phase positions are compared with one another by way of forming differences and, in the event that one or more of the differences deviate(s) from a specified expectation value, the presence of a fault is inferred. The approach allows significantly increased operational reliability of the electric machine to be achieved in particular.

Abstract: A piezoelectric component has a multilayer structure. The piezoelectric component includes piezoelectric ceramic layers, electrode layers arranged among the ceramic layers in a stack such that the electrode layers and the piezoelectric ceramic layers alternate in the stack, and a passivation layer disposed on a lateral surface of the stack. The passivation layer is made from a passivation material that has a crack resistance that is lower than a bond strength of the passivation material.

Abstract: The invention relates, inter alia, to an additional contact (30) for a piezoelectric component (10) in the form of a multilayer structure and to a corresponding component, wherein the piezoelectric component (10) is formed by a stack (17) of alternating piezoelectric ceramic layers and electrode layers. The additional contact (30) has a contact element (31) with a contact zone (33) for connection to an electrical connecting element (20) and with a fastening zone (34) for connection to a metallized part (15, 16). In order to minimize harmful tensile/pressure loads in the additional contact (30), the additional contact (30), especially the contact element (31), is shaped so as to allow for a load distribution of the critical tensile loads, for example by means of at least one bend (32) in the contact element (31).

Abstract: Inter alia, a piezoelectric component (10) in multilayer construction is described, in which a piezoelectric ceramic layer (11) and a electrode layer (12, 13) are always arranged alternately one on top of the other to form a stack (18), whereby every electrode layer (12, 13) extends to at least one lateral surface (19) of the stack (18). In order to protect the component (10) from short circuits and arcing, it is provided on at least one lateral surface (19) with a passivation (20). In order to retain intact the bond of the passivation (20) to the surface (19) of the component (10) at all times, in particular at the appearance of cracks in the ceramic layers (11) according to the invention, the passivation (20) comprises a passivation material that has a crack resistance which is lower than the bonding strength of the passivation material on the surface (19) of the component (10).

Abstract: A piezo actuator with an actuator body has at least one electrically conductive multi-layer film with a rigid electrical terminal element. The multi-layer film controls expansion and attraction of the actuator body. An electrical conduction layer of the multi-layer film has at least one recess to increase flexibility. The recesses in the conduction layer are, for example, photolitho-graphically produced.

Abstract: A piezo actuator (1) is disclosed that has a contact lug (20, 21) for the electrical contacting of an electrode (14, 15) of an actuator member (11). Due to an expansion and contraction of the actuator member, a mechanical stress occurs in the contact lug that is minimized in that the contact lug has a device for adapting the expanse to a dimension of the expansion and contraction. The device is, for example, a deformation material in the form of a wire weave. The piezo actuator is utilized for the drive of an injection valve in an internal combustion engine.

Abstract: A method for manufacturing a monolithic piezoelectric actuator of multilayer design and having a high aspect ratio of more than two built up from a plurality of smaller stacks in a multilayer design, includes alternately layering green piezoceramic films and electrode material, compressing the layers while elevating the temperature to remove the binder and thereby form a composite, stacking several of the composites on one another, and sintering the stack so as to form the monolithic piezoelectric actuator which exhibits an improved mechanical strength with good piezoelectric properties.

Abstract: A piezoelectric actuator, and method of producing same, wherein electrically conductive contact tabs are applied onto metallization strips in such a way that a projecting region remains, so that in the event of cracks nevertheless occurring, such cracks run in the projecting region of the contact tab and are bridged electrically.

Abstract: A piezoelectric component in the form an actuator having a monolithic multi-layer stack is disclosed. The stack comprises a large active cross sectional area and simultaneously exhibits high arc-over resistance between neighboring electrodes of different polarity. For manufacture, only the surface of the stack via which an electrical contacting of the electrode layers ensues is ground after the sintering of a stack composed of piezo ceramic layers and electrode layers arranged on top of one another.

Abstract: A monolithic piezoelectric actuator is made of a stoichiometric PZT ceramic (2) with low A-site doping, and electrode layers (1) containing silver and palladium. It exhibits an improved mechanical strength with good piezoelectric properties. The production process leads to optimum grain sizes and optimum piezoelectric properties irrespective of any B-site doping in the ceramic. Multilayer piezoelectric actuators with high application temperatures up to 150° C. can be obtained.

Abstract: In a method for producing a PZT piezoceramic, an intermediate compound is formed having the formula Zr.sub.x Ti.sub.1-x (O.sub.2 (ZTO) in a hydrothermal process. A ceramic having a desired zirconium/titanium ratio can be produced from two such ZTO powders having respectively different x-values. These powders are blended with lead oxide, and if desired with dopants, and are converted into a PZT powder by calcining. The calcined PZT powder is then sintered to form a high-density PZT ceramic which can be aligned precisely at the morphotropic phase boundary.

Abstract: A composite ultrasound transducer (array) contains piezoelectric ceramic transducer elements which radiate substantially in the longitudinal direction, and are embedded in a polymer matrix. The transducer elements have such a geometrical structure, and are arranged relative to each other, so that the development of oscillation modes perpendicular to the longitudinal direction of the transducer elements is suppressed. A method for manufacturing the composite ultrasound transducer includes the steps of filling a plastic form, having a "negative" of the desired shape of the transducer elements, with ceramic slurry, and pyrolyzing the plastic form after the slurry dries therein. The resulting voids between the hardened ceramic elements are filled with polymer to create the overall composite transducer.

Abstract: An electric centrifugal switch is proposed, in particular for the purpose of safety shutoff upon attainment of a shutoff rpm for fuel injection systems, electrically controlled in an open- or closed-loop manner, of internal combustion engines, which is not vulnerable to rotary oscillations and which effects a rapid shutoff. The centrifugal switch comprises a centrifugal pendulum secured by means of a metal band bearing on a revolving carrier element and a switch attached to the housing and provided with a switching distance from an actuation pin. The centrifugal pendulum carries a flyweight mass on the end of a first lever arm extending substantially in the direction of the rotary axis, and its second lever arm extending at least approximately rectangularly to the rotary axis, is held together with a metal band of the band bearing in constant contact on a roll-off surface located on the carrier element by a restoring spring and, in a preferred embodiment, by means of a supplementary spring element.