Abstract: Aspects of the present disclosure relate to a piezoelectric device having at least one piezoelectric element, which has a support plane oriented to a force introduction element, wherein in the event of a thermal loading of the piezoelectric device in the support plane, expansion differences between the piezoelectric element and the force introduction element occur. To compensate for shear loadings, at least one transition element is arranged between the piezoelectric element and the force introduction element, the E-module of which is smaller than the E-module of the piezoelectric element in the support plane.

Abstract: A clamping jaw for a chuck includes a jaw body on which there is formed at least one jaw step having a step head, which has a sensor on its end face, for holding a clamping insert which is formed from a base leg and two fastening legs projecting from the base leg. On each of the opposite longitudinal sides of the step head there is formed a threaded bore for receiving a fastening screw whose screw head is received in a through-opening which is formed in the fastening leg of the clamping insert that is assigned to the longitudinal side, wherein, on each side, the longitudinal axes of the threaded bore and of the through-opening assigned thereto have an offset when the base leg bears against the end face. Also, a chuck has a chuck body, in which such clamping jaws are arranged in uniformly-distributed radial jaw guides.

Abstract: The invention relates to a method for correcting a misalignment of at least one shafting of a powertrain on a test bench, where at least one piezoelectric force sensor is arranged in a path of force via which a force flow can be transmitted between a load unit of the test bench and a drive unit of the powertrain or the test bench during a transmission of power via the shafting, comprising: performing a force measurement in at least one plane and/or perpendicular to the at least one plane which is intersected by a rotational axis of the shafting and may be substantially perpendicular to the rotational axis; analyzing a measured value or a measured value progression of the force measurement for detecting a misalignment of the shafting; determining target values for a position correction of the load unit or the drive unit in order to minimize the misalignment; and outputting the target values.

Abstract: An external rotor of a device for contactless transmission of rotary movements, for example of an electric motor, a magnetic transmission, a generator or a magnetic coupling, may include a plurality of different permanent magnet segments configured ring segment-like that are alternatingly arranged in a closed permanent magnet segment ring. At least one lateral surface of at least one permanent magnet segment of the plurality of permanent magnet segments may deviate from a radial direction. The at least one permanent magnet segment via the at least one lateral surface may be in contact with another permanent magnet segment of the plurality of permanent magnet segments.

Abstract: An external rotor of a device for contactless transmission of rotary movements, for example of an electric motor, a magnetic transmission, a generator or a magnetic coupling, may include a plurality of different permanent magnet segments configured ring segment-like that are alternatingly arranged in a closed permanent magnet segment ring. At least one lateral surface of at least one permanent magnet segment of the plurality of permanent magnet segments may deviate from a radial direction. The at least one permanent magnet segment via the at least one lateral surface may be in contact with another permanent magnet segment of the plurality of permanent magnet segments.

Abstract: A waste heat device for an exhaust gas system may include a hermetically sealed separation sealing off an area against fluid loss. A drive coupling may drivingly connect in a contactless manner a drive to a device configured to receive the drive work. The drive coupling may include a magnetic clutch arrangement having an inlet side arranged within the separation and an outlet side arranged outside the separation. The outlet side may include an outer rotor and the inlet side may include an inner rotor. The outer rotor and the inner rotor may be separated from one another via a sealing cap having an intermediate wall disposed concentric to the rotors. The intermediate wall may form part of the hermetic separation. A plurality of pole bars of a magnetisable material may be arranged on the intermediate wall and be spaced apart in a circumferential direction.

Abstract: The invention is directed to a method for braking an electric drive motor having a stator and a rotor. The stator has field coils which have electrical phase connections for three motor phases. To generate an electromagnetic rotating field driving the rotor, the phase connections are connected to a supply voltage via switches actuated by a control unit which closes the switches depending on the rotary position of the rotor. To brake a rotating rotor, a braking current is generated by short-circuiting the phase connections. A phase short circuit is switched in between each two phase connections of the field coils with a preset temporal sequence to brake the rotor. The phase connections short-circuited are each selected corresponding to the rotary position of the rotor so that that field coil is short circuited in which the voltage induced by the magnetic field of the rotating rotor passes through its maximum.

Abstract: A portable, handheld work apparatus such as a chain saw has a handle (5, 7) to guide the work apparatus (1) and has an air-cooled, mixture-lubricated combustion engine (10) arranged in a casing as a drive for a work tool (3). The cylinder (11) has a combustion chamber (13) formed therein to which an air/fuel mixture is supplied. The air/fuel mixture is ignited by a spark plug (23) which projects into the combustion chamber (13). An ignition control (30) triggers a spark in dependence on the angular position of the crankshaft (15). A temperature sensor (35, 45, 55) is provided to control the cylinder temperature. The temperature signal of the temperature sensor (35, 45, 55) is connected to a power control (40). When a predetermined temperature is exceeded, the power control (40) changes the operating parameters of the combustion engine (10) in such a manner that the power of the combustion engine (10) is changed.

Abstract: The invention relates to a portable, handheld work apparatus such as a trimmer, a cut-off machine, a chain saw or the like, having a motor (5, 33) to drive a rotating, exchangeable work tool (13). A control unit (15) serves to control the operation of the motor (5, 33). The control unit (15) determines the rotational speed (n) and/or the power (P) of the motor (5, 33). According to the invention, the motor (5, 33) can be operated in a first operating mode (I) with reduced rotational speed (n0) and/or power (P0) and in at least a second operating mode (II) with an increased rotational speed (n1) and/or power (P1). In dependence on a release signal, the control uses exclusively the first operating mode (I) for a limited operation and the second operating mode (II) for an expanded operation.

Abstract: The invention is directed to a method for braking an electric drive motor having a stator and a rotor. The stator has field coils which have electrical phase connections for three motor phases. To generate an electromagnetic rotating field driving the rotor, the phase connections are connected to a supply voltage via switches actuated by a control unit which closes the switches depending on the rotary position of the rotor. To brake a rotating rotor, a braking current is generated by short-circuiting the phase connections. A phase short circuit is switched in between each two phase connections of the field coils with a preset temporal sequence to brake the rotor. The phase connections short-circuited are each selected corresponding to the rotary position of the rotor so that that field coil is short circuited in which the voltage induced by the magnetic field of the rotating rotor passes through its maximum.

Abstract: In a method for operating an internal combustion engine for adjusting a desired fuel/air mixture, wherein the rotary speed is determined by an operating curve based on a fuel/air mixture composition, wherein the operating curve has ascending and descending branches and a maximum, wherein a lambda value is smaller than 1 on the descending branch, it is first determined by statistic evaluation whether the operating point is on the ascending or descending branch. In a second method step, when the operating point is not on a desired branch of the operating curve desired as a starting point for a third method step, at least one operating parameter is changed until the operating point is positioned on the desired branch. In a third method step, the maximum of the operating curve is determined. Based on the determined maximum, the desired operating point of the internal combustion engine is then adjusted.

Abstract: The invention relates to a portable handheld work apparatus such as a cutoff machine, motor-driven chain saw, brushcutter, blower apparatus or the like. The apparatus includes a drive motor (2) for driving a work tool (6) and is provided with a security circuit (20). The security circuit (20) switches the drive motor (2) of the work apparatus into an operational-ready state or into an out-of-service state in dependence upon received signals of a receiver unit (18). The receiver unit is configured to receive at least one operating code. The receiver unit (18) is configured for receiving a service code (27) and, with the receipt of a service code, switches the drive motor into only a temporary service state.

Abstract: An internal combustion engine (8) has an ignition device, a device for supplying fuel and a device for detecting the rpm of the engine (8). The engine (8) includes a permissible limit rpm (ng) and a control range (A) of the rpm (n) above the limit rpm (ng). A method for operating the engine (8) provides that the rpm of the engine (8) is limited in the control range (A) because of suppression of the ignition in individual engine cycles wherein the rpm (n) lies above a control rpm (na) lying in the control range (A). In the control range, and to improve the exhaust-gas values, the noncombustion engine cycle ratio (NECR) is adjusted. The NECR indicates the ratio of the number of engine cycles wherein the ignition is suppressed to the total number of ignitions.

Abstract: The invention relates to a portable handheld work apparatus such as a cutoff machine, motor-driven chain saw, brushcutter, blower apparatus or the like. The apparatus includes a drive motor (2) for driving a work tool (6) and is provided with a security circuit (20). The security circuit (20) switches the drive motor (2) of the work apparatus into an operational-ready state or into an out-of-service state in dependence upon received signals of a receiver unit (18). The receiver unit is configured to receive at least one operating code. The receiver unit (18) is configured for receiving a service code (27) and, with the receipt of a service code, switches the drive motor into only a temporary service state.

Abstract: The invention relates to a portable, handheld work apparatus such as a trimmer, a cut-off machine, a chain saw or the like, having a motor (5, 33) to drive a rotating, exchangeable work tool (13). A control unit (15) serves to control the operation of the motor (5, 33). The control unit (15) determines the rotational speed (n) and/or the power (P) of the motor (5, 33). According to the invention, the motor (5, 33) can be operated in a first operating mode (I) with reduced rotational speed (n0) and/or power (P0) and in at least a second operating mode (II) with an increased rotational speed (n1) and/or power (P1). In dependence on a release signal, the control uses exclusively the first operating mode (I) for a limited operation and the second operating mode (II) for an expanded operation.

Abstract: The invention relates to a portable, handheld work apparatus such as a chain saw having a handle (5, 7) to guide the work apparatus (1) and having an air-cooled, mixture lubricated combustion engine (10) arranged in a casing as a drive for a work tool (3). The cylinder (11) has a combustion chamber (13) formed therein to which an air/fuel mixture is supplied. The air/fuel mixture is ignited by a spark plug (23) which projects into the combustion chamber (13). An ignition control (30) triggers a spark in dependence on the angular position of the crankshaft (15). A temperature sensor (34, 45, 55) is provided to control the cylinder temperature. The temperature signal of the temperature sensor (34, 45, 55) is connected to a power control (40). When a predetermined temperature is exceeded, the power control (40) changes the operating parameters of the combustion engine (10) in such a manner that the power of the combustion engine (10) is changed.

Abstract: In a method for operating an internal combustion engine for adjusting a desired fuel/air mixture, wherein the rotary speed is determined by an operating curve based on a fuel/air mixture composition, wherein the operating curve has ascending and descending branches and a maximum, wherein a lambda value is smaller than 1 on the descending branch, it is first determined by statistic evaluation whether the operating point is on the ascending or descending branch. In a second method step, when the operating point is not on a desired branch of the operating curve desired as a starting point for a third method step, at least one operating parameter is changed until the operating point is positioned on the desired branch. In a third method step, the maximum of the operating curve is determined. Based on the determined maximum, the desired operating point of the internal combustion engine is then adjusted.

Abstract: An internal combustion engine (8) has an ignition device, a device for supplying fuel and a device for detecting the rpm of the engine (8). The engine (8) includes a permissible limit rpm (ng) and a control range (A) of the rpm (n) above the limit rpm (ng). A method for operating the engine (8) provides that the rpm of the engine (8) is limited in the control range (A) because of suppression of the ignition in individual engine cycles wherein the rpm (n) lies above a control rpm (na) lying in the control range (A). In the control range, and to improve the exhaust-gas values, the noncombustion engine cycle ratio (NECR) is adjusted. The NECR indicates the ratio of the number of engine cycles wherein the ignition is suppressed to the total number of ignitions.