A fusion gear reducer includes a first-stage gear reduction unit and a second-stage gear reduction unit both in a housing. The first-stage gear reduction unit includes a sun gear, a planet gears support, planet gears spaced around the sun gear and meshed therewith, and a ring gear around the planet gears and meshed therewith. The second-stage gear reduction unit includes spaced rollers arranged as a circle, roller grooves, wells formed on an inner surface of the housing, and a cam surface formed on an outer surface of the ring gear so that the ring gear is output of the first-stage gear reduction unit and input of the second-stage gear reduction unit. The roller grooves are disposed on outer surfaces of the planet gears so that the planet gears are output of the second-stage gear reduction unit. The simplified fusion gear reducer solves the problem of bulkiness of gear reducer.

A flex spline torque transfer device using force applied at multiple positions for each area of contact between the flex spline and outer ring. The positions of at which force is applied may be outside the areas of contact. This design may also be used in conjunction with a magnetic method of applying force to the flex spline, mechanical force acting as a constraint to prevent the flex spline from fully disengaging from the outer ring.

A gearbox that is configured to transmit torque from a motor shaft to a load shaft includes a limit mechanism The limit mechanism includes a strain wave gear including a circular spline, a flex spline and a wave generator. The circular spline is fixed to a housing of the gearbox coaxially with the load shaft, the flex spline is formed on a flexible rim of a rotatable cup that is coaxial with the load shaft, and the wave generator is coupled to the load shaft so as to rotate at the same angular velocity. The limit mechanism further includes at least one limiter structure coupled to the rotatable cup and at least one fixed switch, and is configured to stop rotation of the load shaft when the limiter structure engages the fixed switch.

A disc recliner 18 for a seat assembly includes a fixed plate 22 secured to a seat cushion 12 and a rotatable plate 30 secured to a seat back 14. Each of the fixed and rotatable plates 22,30 has a plurality of teeth 40,48, the number of teeth not being equal. A flex spline 26 has a plurality of teeth 52, the number of teeth being equal to the number of teeth on the fixed plate 22. A wave generator 28 causes a portion of the teeth 52 on the flex spline 26 to meshingly engage with the teeth 40,48 on the fixed and rotatable plates 22,30. Rotation of the wave generator 28 causes the teeth 52 on the flex spline 26 which meshingly engage with the teeth 40,48 on the fixed and rotatable plates 22,30 to change, thereby causing the rotatable plate 30 to rotate relative to the fixed plate 22, which in turn causes the seat back 14 to pivot relative to the seat cushion 12

The invention relates to a wave generator for a strain wave gear, said wave generator in a main portion having a bearing seat for a radially flexible roller bearing. The wave generator is distinguished by having a cone portion that adjoins the main portion in the axial direction and tapers off in a direction away from the main portion.

A wave generator of a strain wave gearing has a rigid plug provided with an elliptical outer peripheral surface, and a roller bearing. The outer peripheral surface of the plug is provided with a major-axis-side outer-peripheral surface portion formed at a major axis position L1, and a minor-axis-side outer-peripheral surface portion formed at a minor axis position L2. The major-axis-side outer-peripheral surface portion is a tapered surface that is tapered along a center axis line, and the minor-axis-side outer-peripheral surface portion is an inverted tapered surface that is tapered in the opposite direction. An externally toothed gear can be supported and flexed into an elliptical shape without partial contact by using the wave generator in which the roller bearing is used.

A strain wave gearing has contact parts which are the portions to be lubricated other than the teeth of an externally toothed gear and an internally toothed gear, the contact parts being respectively lubricated with an inorganic lubricating powder having a lamellar crystal structure. The lubricating powder, during the operation of the strain wave gearing, is crushed between the contact surfaces of each of the contact parts to move and adhere to the contact surfaces, thereby forming thin surface films thereon. Additionally, the powder is thinly spread by pressure and reduced into finer particles to change into a shape which facilitates intrusion into the space between the contact surfaces. By both the fine particles having changed in shape and the surface films, the lubrication of the contact parts is maintained. Neither the fine particles nor the surface films are viscous.

A harmonic drive assembly and fluid-powered linear motors with both axial pistons are rotary piston arrangements incorporating the harmonic drive assembly are disclosed. The motors may be used in downhole drilling applications, but the drive assembly and/or motors may be used in other applications. The assembly, motors and methods use advanced harmonic drives, advanced helical drives, and combinations thereof with 1) motors with axial pistons and reciprocating linear rings to convert reciprocative axial motion to continuous rotary motion, and 2) motors with rotary pistons and reciprocating linear rings to rectify reciprocative rotary motion to continual rotary motion to improve performance over prior configurations. Axial pistons provide a robust simple solution for generating rotation; Rotational pistons provide increased torque generation as the torque generated is proportional to motor length. Since downhole drills are long, a high-torque motor can be produced using this method.

A strain wave gearing unit has a unit housing, a strain wave gearing, and a bearing device. Balls of a bearing part of the bearing device are positioned on the diametrically outer side with respect to a cylindrical barrel part of an externally toothed gear. The diameter S of the balls is 0.05 to 0.15 times the pitch diameter D of the externally toothed gear. The centers of the balls are positioned between a point at a distance of 1.2 times the diameter S toward the cylindrical-barrel-part side from an inner-side end surface of a diaphragm along a center axis and a point at a distance of 1 times the diameter S toward a side opposite the cylindrical barrel part from the inner-side end surface. The bearing device can be configured to be used in common for strain wave gearing units having different axial lengths.

A harmonic drive includes an internally toothed housing element (2), a pot-shaped output element (4) which is mounted in the housing element (2), and a likewise pot-shaped, resilient drive element (19) which is connected to the output element (4) and has an external toothing system (13) which meshes with the internal toothing system (14) of the housing element (2). A spring element (35) is active between the housing element (2) and the output element (4), which spring element (35) is arranged in an annular chamber which is delimited radially to the inside by a sleeve section (24) of the resilient drive element (19), radially to the outside by a cylindrical section (5) of the output element (4), and in the axial direction firstly by an annular disc-shaped surface (23) of the housing element (2) and secondly by a bottom (9) of the output element (4).