An assembly and a method for manufacturing an assembly for transmitting torque to an aircraft actuator. The assembly and method include a torque tube having a longitudinal axis and an end fitting. The ending fitting includes a connector portion and an engagement portion that is inserted into the torque tube. The engagement portion includes a first end adjacent the connector portion, a second end opposite the first end, and a coupling region between the first and second end that includes an outer coupling surface having an outer diameter and a continuous groove formed thereon. The continuous groove includes two axial grooves that extend along the outer coupling surface along the longitudinal axis and a first parallel groove that extends circumferentially about the longitudinal axis along the outer coupling surface that joins the two axial grooves.

An assembly and a method for manufacturing an assembly for transmitting torque to an aircraft actuator. The assembly and method include a torque tube having a longitudinal axis and an end fitting. The ending fitting includes a connector portion and an engagement portion that is inserted into the torque tube. The engagement portion includes a first end adjacent the connector portion, a second end opposite the first end, and a coupling region between the first and second end that includes an outer coupling surface having an outer diameter and a continuous groove formed thereon. The continuous groove includes two axial grooves that extend along the outer coupling surface along the longitudinal axis and a first parallel groove that extends circumferentially about the longitudinal axis along the outer coupling surface that joins the two axial grooves.

A method for manufacturing a pole tube having two magnetic pole tube components and having one nonmagnetic ring, which is situated axially between the pole tube components, for an electromagnet, in particular for a solenoid valve of an automatic transmission in a motor vehicle, including the following: concentric configuration and/or centering of the pole tube components and of the ring, in particular on a centering pin; form-fitting connection, in particular by extrusion coating and/or casting an exterior lateral surface of the pole tube components and of the ring.

A method for manufacturing a pole tube having two magnetic pole tube components and having one nonmagnetic ring, which is situated axially between the pole tube components, for an electromagnet, in particular for a solenoid valve of an automatic transmission in a motor vehicle, including the following: concentric configuration and/or centering of the pole tube components and of the ring, in particular on a centering pin; form-fitting connection, in particular by extrusion coating and/or casting an exterior lateral surface of the pole tube components and of the ring.

An initial variation learning control is executed when a learning condition is satisfied each time the learning condition is satisfied, with the aim of absorbing initial variations of manufacturing errors or variations of components of a second clutch (CL2). When the number of times of learning control is counted and this becomes a predetermined number (e.g. five times), after that, a deterioration variation learning control, which is equivalent to the initial variation learning control, is executed only once a trip from ON of a key switch to OFF of the key switch. With this, a frequency of execution of the learning control can be reduced, and the number of times of the learning can be reduced. It is therefore possible to suppress energy consumption and improve energy efficiency in stand-by pressure learning control of the second clutch that serves as a starter clutch.

A method for automatic detection of need for clutch calibration includes registering and storing in a data memory, before or in connection with engine shut down, a value of a clutch operating parameter, registering a corresponding value of the clutch operating parameter in connection with subsequent engine start up, and determining need for clutch calibration if the difference between the stored value of the clutch operating parameter and the corresponding value of the clutch operating parameter exceeds a predetermined threshold value.

One aspect of the present disclosure relates to an apparatus comprising a first end fitting. The first end fitting comprises a tube engagement portion. The tube engagement portion comprises an outer coupling surface. The outer coupling surface comprises a first virtual cross-section. The first virtual cross-section comprises a first transverse inflection point. Each point along the first virtual cross-section has a first virtual tangent line coplanar with the first virtual cross-section.

One aspect of the present disclosure relates to an apparatus comprising a first end fitting. The first end fitting comprises a tube engagement portion. The tube engagement portion comprises an outer coupling surface. The outer coupling surface comprises a first virtual cross-section. The first virtual cross-section comprises a first transverse inflection point. Each point along the first virtual cross-section has a first virtual tangent line coplanar with the first virtual cross-section.