A power transmission device includes a pin gear having a plurality of power transmission pins that are relatively moved corresponding to a tooth shape formed on an outer gear, a motor arranged in a direction crossing a rotation axis of the pin gear, and generating power to rotate the pin gear, and a motion transfer unit connected to the pin gear and the motor between the pin gear and the motor, and transferring a rotational motion of the motor to a rotational motion of the pin gear.

A drive system 20, 20′ for rotating a wheel 11, 11′ of an aircraft landing gear 10, 10′, is disclosed having a drive element 24, 24′, a motor 21, 21′ operable to rotate the drive element, and a driven gear 25, 25′ adapted to be attached to the wheel. The drive system has a drive configuration in which the drive element is capable of meshing with the driven gear to drive the driven gear, wherein the drive system further comprises a transmission error measurement apparatus 30, 40, the apparatus configured to obtain, over time, measurement data of one or more characteristics of the drive system when in the drive configuration, the measurement data providing an indication of a transmission error between a torque commanded by the motor and a resulting torque at the driven gear. An aircraft 100 and a method of providing an indication of a transmission error in a drive system is disclosed.

A drive system 20, 20′ for rotating a wheel 11, 11′ of an aircraft landing gear 10, 10′, is disclosed having a drive element 24, 24′, a motor 21, 21′ operable to rotate the drive element, and a driven gear 25, 25′ adapted to be attached to the wheel. The drive system has a drive configuration in which the drive element is capable of meshing with the driven gear to drive the driven gear, wherein the drive system further comprises a transmission error measurement apparatus 30, 40, the apparatus configured to obtain, over time, measurement data of one or more characteristics of the drive system when in the drive configuration, the measurement data providing an indication of a transmission error between a torque commanded by the motor and a resulting torque at the driven gear. An aircraft 100 and a method of providing an indication of a transmission error in a drive system is disclosed.

Coaxial gear mechanism (1) includes a toothing (5) which is oriented axially with respect to an axis of rotation (3) of the coaxial gear mechanism (1), a tooth carrier (7) which in each case has axially oriented guides (9), and tooth pins (11) which each comprise a body (50), which is mounted so as to be axially displaceable in a guide (9) of the tooth carrier (7), and a head region (51), wherein the head region (51) includes at least one tooth (52) for engagement with the toothing (5), and wherein the tooth carrier (7) wherein the tooth carrier has an irregular angular pitch.

Coaxial gear mechanism (1) includes a toothing (5) which is oriented axially with respect to an axis of rotation (3) of the coaxial gear mechanism (1), a tooth carrier (7) which in each case has axially oriented guides (9), and tooth pins (11) which each comprise a body (50), which is mounted so as to be axially displaceable in a guide (9) of the tooth carrier (7), and a head region (51), wherein the head region (51) includes at least one tooth (52) for engagement with the toothing (5), and wherein the tooth carrier (7) wherein the tooth carrier has an irregular angular pitch.

Coaxial gear mechanism (1), having a toothing (5) oriented axially with respect to an axis of rotation (3) of the coaxial gear mechanism (1), a tooth carrier (7) with axially oriented guides (9), tooth pins (11) which each have a body (41), which is mounted in an axially displaceable manner in a guide (9) of the tooth carrier (7), and a head region (51), wherein the head region (51) has at least one tooth (53) for engagement with the toothing (5), and wherein the head region (51) is configured to be wider than the body (41).

Coaxial gear mechanism (1), having a toothing (5) oriented axially with respect to an axis of rotation (3) of the coaxial gear mechanism (1), a tooth carrier (7) with axially oriented guides (9), tooth pins (11) which each have a body (41), which is mounted in an axially displaceable manner in a guide (9) of the tooth carrier (7), and a head region (51), wherein the head region (51) has at least one tooth (53) for engagement with the toothing (5), and wherein the head region (51) is configured to be wider than the body (41).

A mechanical linear actuator in an aircraft brake may include a ball nut, a ball screw, and an actuator drive unit housing. The ball screw may rotate to drive the ball nut axially. The ball screw and the actuator drive unit housing may form a series of annular raceways. The ball screw may have a first window corresponding to a first raceway and a second window corresponding to a second raceway. Balls may be inserted into the first raceway through the first window and into the second raceway through the second window.

A roller screw mechanism comprising a screw, provided with an outer thread, a nut positioned around and coaxially to the screw, the nut being provided with an inner thread, and a plurality of rollers inserted between the screw and the nut, each comprising an outer thread engaged with the outer thread of the screw and with the inner thread of the nut. Each of the threads of the screw, rollers and nut comprise first and second axially opposite flanks, respectively forming a first and second angle with a plane perpendicular to the central axis of the screw, the first and second flanks of each thread of the rollers respectively being in contact with the first and second flanks of the nut's thread and with the first and second flanks of the screw's thread. The value of the first angle is different from the value of the second angle.

A ball screw device includes an elongated shaft having an outer groove, a ball nut having a screw hole for receiving the elongated shaft and having a passage communicating with the screw hole of the ball nut, and a lubricating device includes an inner cylindrical element engaged onto the elongated shaft and secured to the ball nut, a housing attached onto the cylindrical element and contacted with the ball nut, and the housing includes a chamber for receiving a lubricating grease, an oil distributing member is engaged into the passage of the ball nut and engaged into the screw hole of the ball nut for engaging with the elongated shaft, and an inner element is engaged in the housing and engaged with the distributing member for supplying the lubricating grease to the distributing member.