A transmission structure of a helicopter according to one aspect is a transmission structure that transmits power from a prime mover to a rotary wing in the helicopter. The transmission structure includes: a housing; an input shaft that transmits the power of the prime mover to a gear arranged in the housing; a bearing supporting the input shaft in the housing such that the input shaft is rotatable, the bearing including an annular inner ring that holds the input shaft, an annular outer ring that is arranged outside the inner ring in a radial direction and fixed to the housing, and rolling elements sandwiched between the inner ring and the outer ring; and a sleeve that is sandwiched between an inner peripheral surface of the inner ring and the input shaft and is lower in heat conductivity than the inner ring and the input shaft.

A transmission structure of a helicopter according to one aspect is a transmission structure that transmits power from a prime mover to a rotary wing in the helicopter. The transmission structure includes: a housing; an input shaft that transmits the power of the prime mover to a gear arranged in the housing; a bearing supporting the input shaft in the housing such that the input shaft is rotatable, the bearing including an annular inner ring that holds the input shaft, an annular outer ring that is arranged outside the inner ring in a radial direction and fixed to the housing, and rolling elements sandwiched between the inner ring and the outer ring; and a sleeve that is sandwiched between an inner peripheral surface of the inner ring and the input shaft and is lower in heat conductivity than the inner ring and the input shaft.

A rotary table (1) includes a base body (10), a worm wheel (21), an inner ring (22), a plurality of rolling elements, and a worm screw unit (30). The worm screw unit (30) includes a worm screw (31) held to be rotatable around an axis and having a second gear (31A) meshing with the first gear (215), and a worm screw housing (32) surrounding and holding the worm screw (31) and being fixed to contact the holding surface at a planar contacting surface thereof. One of the holding and contacting surfaces has a cylindrical pin (33) arranged to protrude therefrom. The other of the holding and contacting surfaces has a first recess (11) formed to receive the pin (33), the first recess having a width corresponding to the pin (33) and being elongated in the radial direction of the worm wheel (21).

A rotary table (1) includes a base body (10), a worm wheel (21), an inner ring (22), a plurality of rolling elements, and a worm screw unit (30). The worm screw unit (30) includes a worm screw (31) held to be rotatable around an axis and having a second gear (31A) meshing with the first gear (215), and a worm screw housing (32) surrounding and holding the worm screw (31) and being fixed to contact the holding surface at a planar contacting surface thereof. One of the holding and contacting surfaces has a cylindrical pin (33) arranged to protrude therefrom. The other of the holding and contacting surfaces has a first recess (11) formed to receive the pin (33), the first recess having a width corresponding to the pin (33) and being elongated in the radial direction of the worm wheel (21).

An electric parking brake actuator assembly is proposed. The electric parking brake actuator assembly includes: an outer housing including an inner space in which a gear installation space and a motor installation space are formed; an inner housing installed in the inner space of the outer housing, and including a brush card part and a gear installation part integrated together; a motor assembly coupled to the brush card part to be electrically connected thereto, and installed in the motor installation space; a gear assembly installed at the gear installation part and at the gear installation space, and changing and transmitting the rotational speed of the motor assembly; and a cover housing coupled to the outer housing with the inner housing interposed therebetween, and including a shaft insertion portion.

An electric parking brake actuator assembly is proposed. The electric parking brake actuator assembly includes: an outer housing including an inner space in which a gear installation space and a motor installation space are formed; an inner housing installed in the inner space of the outer housing, and including a brush card part and a gear installation part integrated together; a motor assembly coupled to the brush card part to be electrically connected thereto, and installed in the motor installation space; a gear assembly installed at the gear installation part and at the gear installation space, and changing and transmitting the rotational speed of the motor assembly; and a cover housing coupled to the outer housing with the inner housing interposed therebetween, and including a shaft insertion portion.

There is provided a perpendicular speed reducer including an input shaft, a reduction mechanism that reduces a speed of rotation of the input shaft, an output shaft that outputs the speed-reduced rotation, and a casing that accommodates the reduction mechanism. The input shaft and the output shaft are perpendicular to each other. The casing includes a bearing hole formed on a first side surface to support the output shaft, a fin provided along a direction toward the bearing hole, and a groove portion provided along an axial direction of the output shaft on a second side surface adjacent to the first side surface.

There is provided a perpendicular speed reducer including an input shaft, a reduction mechanism that reduces a speed of rotation of the input shaft, an output shaft that outputs the speed-reduced rotation, and a casing that accommodates the reduction mechanism. The input shaft and the output shaft are perpendicular to each other. The casing includes a bearing hole formed on a first side surface to support the output shaft, a fin provided along a direction toward the bearing hole, and a groove portion provided along an axial direction of the output shaft on a second side surface adjacent to the first side surface.

A compact geared reduction unit for application with transmission shaft subjected to radial loads, comprising a box-like body inside which a gear system is accommodated for the transmission of rotary motion from a driving shaft to a transmission shaft, which is provided with an output reduction stage of the epicyclic type; the output reduction stage comprises a driving sun gear which rotates about a main axis and a ring gear which is integrally associated with the box-like body, between which multiple planet gears are engaged which are supported in rotation about respective longitudinal axes which are parallel to the main axis by a transmission planet carrier, which in turn rotates about the main axis and is associated so as to be integral in rotation with the transmission shaft at a connection region. The reduction unit furthermore provides for rolling means adapted to support radial loads associated with the transmission shaft.

A compact geared reduction unit for application with transmission shaft subjected to radial loads, comprising a box-like body inside which a gear system is accommodated for the transmission of rotary motion from a driving shaft to a transmission shaft, which is provided with an output reduction stage of the epicyclic type; the output reduction stage comprises a driving sun gear which rotates about a main axis and a ring gear which is integrally associated with the box-like body, between which multiple planet gears are engaged which are supported in rotation about respective longitudinal axes which are parallel to the main axis by a transmission planet carrier, which in turn rotates about the main axis and is associated so as to be integral in rotation with the transmission shaft at a connection region. The reduction unit furthermore provides for rolling means adapted to support radial loads associated with the transmission shaft.