A dynamic damper includes: a mass body that is disposed inside a rotation shaft and extends along a shaft center of the rotation shaft; and an elastic body interposed between the mass body and the rotation shaft. Further, the mass body is allowed to vibrate to a linear motion state, the elastic body includes: first and second contact surfaces, when the gear generates vibration so as to fall from a radial direction of the rotation shaft to an axial direction side of the rotation shaft, compressive stress acts on the elastic body by the mass body vibrating so as to push the first contact surface in response to the vibration, and when the gear generates vibration along the axial direction, compressive stress acts on the elastic body by the mass body coming in the linear motion state and vibrating so as to push the second contact surface.

A dynamic damper for suppressing vibration generated by a gear attached to a rotation shaft, the dynamic damper, includes: a mass body that is disposed inside a rotation shaft having a hollow shape and extends along a shaft center of the rotation shaft; and an elastic body that couples the mass body to the rotation shaft. Further, a flow path for lubricating liquid to flow is provided between an inner peripheral surface of the rotation shaft and the mass body, and the flow path is formed by the inner peripheral surface of the rotation shaft at an axial position where the elastic body is disposed.

Object: To provide a planetary gear mechanism with a free-wheel mechanism that can prevent seizing of a thrust plate and can increase the degree of freedom in setting of a gear ratio. Means to Solve the Problem: A planetary gear mechanism 100 is a planetary gear mechanism with a free-wheel mechanism for reducing the output of a hydraulic motor 104 and transmitting the reduced output. The planetary gear mechanism 100 includes: a housing 108 configured to be decelerated and rotated; a cover 128 that seals an end surface 126 of the housing; a sun shaft 132 configured to be splined to a motor shaft 106 of the hydraulic motor; a first sun gear 142 formed in one piece with the sun shaft; a first planetary gear 144 meshed with the first sun gear; a carrier 146 that supports a shaft 148 of the first planetary gear; a thrust plate 160 that is disposed toward the cover relative to the first planetary gear, and is configured to restrict a movement of the carrier; a hole 164 that is formed in the thrust plate and through which the first sun gear can be passed; a maintenance hole 166 that is formed in the cover and through which the first sun gear can be passed; and a plug 162 configured to close the maintenance hole.

A transmission includes a shaft-hub connection designed as a serration and having an axial extent along a shaft axis, and an oil supply line to the serration in order to lubricate a relative movement in the serration between a shaft side and a hub side of the shaft-hub connection. The oil supply line is designed to open from radially inward directly into a cavity on the serration to enable supply of oil to the serration at an oil pressure that prevails in the cavity.

There is provided a mechanical paradox planetary gear mechanism, including: a sun gear configured to be rotatable together with rotation of an input shaft; a plurality of first planetary gears arranged around the sun gear at equal intervals, and configured to rotate about their own axes while revolving around the sun gear in a state in which the first planetary gears mesh with the sun gear; a first internal gear arranged around the plurality of first planetary gears, and configured to mesh with the plurality of first planetary gears; a second internal gear arranged in the same axis as the first internal gear; and a plurality of second planetary gears respectively arranged on the same axes as the plurality of first planetary gears, and configured to mesh with the second internal gear.

A bicycle rear sprocket assembly comprises at least one sprocket having a total tooth number that is equal to or larger than 15. The at least one sprocket includes at least ten internal spline teeth configured to engage with a bicycle hub assembly.

A method of manufacturing a gear shaft including depositing only a first material via directed energy deposition (DED), forming a first portion of the gear shaft via the depositing only the first material via directed energy deposition (DED), forming a transitioning portion of the gear shaft via depositing of a varying ratio of the first material with a second material via DED, and forming a second portion of the gear shaft via the depositing via DED of only the second material.

A robotic surgical tool includes a drive housing having first and second ends, a spline extending between the ends and including a drive gear that rotates with spline rotation, and a carriage mounted to the spline. A shaft extends from the carriage, penetrates the first end, and has an end effector arranged at a distal end. An activating mechanism is housed in the carriage and includes an input gear operatively coupled to the drive gear such that rotation of the drive gear correspondingly rotates the input gear, and a firing rod defining external threads threadably engageable with internal threads of the input gear. The firing rod is coupled to a knife at the end effector such that movement of the firing rod correspondingly moves the knife in the same direction. The drive gear is rotated to rotate the input gear and thereby move the firing rod and the knife.

A power transmission device includes a pinion gear having a large pinion gear and a small pinion gear, a carrier that supports the pinion gear, a ring gear that engages with the small pinion gear, an oil supply unit positioned above a horizontal line that passes through a revolution center of the pinion gear, and a downstream side wall part facing a gear surface of the large pinion gear. The downstream side wall part is arranged to be adjacent to the oil supply unit further downstream in a revolution direction of the pinion gear than the oil supply unit when viewed from an axial direction.

A power transmission device includes a box, a case disposed in the box, a differential mechanism housed in the case, and a planetary gear mechanism disposed in the box and supported by the case. The planetary gear mechanism includes a sun gear and a pinion gear that engages with the sun gear. The box has a shelf part above a horizontal line that passes through a revolution center of the pinion gear. The shelf part is arranged at a position that does not overlap the sun gear when viewed from radially above.