The subject matter of this specification can be embodied in, among other things, a rotary actuator that includes a first rotary actuator assembly having a first housing, a first mounting assembly radially projecting from a first longitudinal end of the first housing and defining a first axial aperture, and a first output shaft extending into the first axial aperture, a second rotary actuator assembly having a second housing, a second mounting assembly radially projecting from a second longitudinal end of the second housing and defining a second axial aperture, and a second output shaft extending into the second axial aperture, and a bearing assembly having an outer surface in contact with at least one of the first mounting assembly and the second mounting assembly, and an inner surface in contact with at least one of the first rotor assembly and the second rotor assembly.

A rotary joint, including: a hydraulic follow-up mechanism and a rotary transmission mechanism. The hydraulic follow-up mechanism includes a cylinder body, a valve sleeve, a valve core, a valve body, a left end cover and a right end cover. The rotary transmission mechanism includes a tray, a stabilizing ring, a follow-up disk, a torque transfer disk and a stable supporting wheel mechanism. The left end cover and the right end cover are arranged at the left and right ends of the cylinder body, respectively. The valve body is concentrically mounted in a cylindrical hollow chamber of the cylinder body. The output shaft at the right end of the valve body projects out of the right end cover. The right end of the valve core is provided with a valve core torque transfer shaft extending rightwards through the right end of the valve body.

The subject matter of this specification can be embodied in, among other things, a rotary actuator that includes a housing defining a first arcuate chamber portion and comprising a first cavity, a first open end, a first seal carrier assembly defining a second arcuate chamber portion and comprising a second cavity in fluid communication with the first cavity, a first piston seal, a second open end, and a third open end opposite the second open end, a first face seal in sealing contact with the housing proximal to the first open end and the second open end, a rotary output assembly, and an arcuate-shaped first piston disposed in said housing for reciprocal movement in the first arcuate chamber portion and in the second arcuate chamber portion.

A rotary actuator, including a manifold block and a rotor assembly that includes a rotor shaft and a plurality of arcuate pistons attached to the rotor shaft, each arcuate piston curving at a set radial distance from the rotor shaft, and each piston attached to the rotor shaft via a crank arm. A pressure chamber assembly coupled to the manifold block defines a plurality of piston pressure chambers that receive and at least partially enclose each arcuate piston, including a plurality of gland seals disposed adjacent the entrance of each piston pressure chamber to create a seal between the inner surface of the pressure chamber and the outer surface of the arcuate piston. Each gland seal includes an inner seal that engages the piston surface of the arcuate piston, and plural outer seals that engage the inner surface of the piston pressure chamber, forming a hydraulic seal.

The subject matter of this specification can be embodied in, among other things, a fluid actuator including a housing defining a first chamber having a first cavity and a first open end, a first piston assembly including a tubular first piston defining a second chamber having a second cavity and a second open end, disposed in said first housing for reciprocal movement in the first chamber through the first open end, wherein a first seal, the first cavity, and the first piston define a first pressure chamber, and a second piston assembly having an second piston disposed in said first piston assembly for reciprocal movement in the second chamber through the second open end, wherein a second seal, the second cavity, and the second piston define a second pressure chamber, and a first portion of the second piston contacts a first end effector.

There is disclosed a rotary actuator apparatus for hydraulically or pneumatically rotating a robotic joint. In an embodiment the apparatus comprises: a curved piston rotatably coupled to an axel shaft, and positioned within a curved piston chamber; resilient barrier modules are adapted to separate the curved piston within the curved piston chamber from first and second hydraulic or pneumatic chambers on either side of the curved piston chamber; whereby, in use, the curved piston is configured to rotate about the axel shaft upon hydraulic or pneumatic pressure being applied to at least one of the first and second hydraulic or pneumatic chambers.

A powertrain has a continuously variable transmission including a shaft rotatable about an axis. The CVT further comprises a variator assembly that includes a pulley supported on the shaft. The pulley has a movable sheave with a ramp surface. The movable sheave is axially movable on the shaft. The variator assembly also includes an endless rotatable device frictionally engaged with the movable sheave. An actuator mechanism includes a wedge component supported on the shaft. The wedge component has a wedge surface that automatically engages the ramp surface when torque on the shaft is in a first direction. The wedge surface applies a wedge force on the ramp surface. The actuator mechanism further includes an actuator that is operatively connected to the movable sheave and is activatable to apply a force on the movable sheave.

The subject matter of this specification can be embodied in, among other things, an articulated joint includes a first rotary actuator having a first housing defining a first arcuate chamber comprising a first cavity, and an arcuate-shaped first piston having a first radius of curvature and disposed in said first housing for reciprocal movement in the first arcuate chamber, a second rotary actuator having a second housing defining a second arcuate chamber comprising a second cavity, and an arcuate-shaped second piston having a second radius of curvature and disposed in said second housing for reciprocal movement in the second arcuate chamber, wherein a first radial side of the first piston relative to the first radius of curvature is in bearing contact with a first radial side of the second piston relative to the second radius of curvature at a contact point between the first axis and the second axis.

The subject matter of this specification can be embodied in, among other things, a rotary actuator that includes a housing defining a first arcuate chamber portion and comprising a first cavity, a first open end, a first seal carrier assembly defining a second arcuate chamber portion and comprising a second cavity in fluid communication with the first cavity, a first piston seal, a second open end, and a third open end opposite the second open end, a first face seal in sealing contact with the housing proximal to the first open end and the second open end, a rotary output assembly, and an arcuate-shaped first piston disposed in said housing for reciprocal movement in the first arcuate chamber portion and in the second arcuate chamber portion.

There is disclosed a rotary actuator apparatus for hydraulically or pneumatically rotating a robotic joint. In an embodiment the apparatus comprises: a curved piston rotatably coupled to an axle shaft, and positioned within a curved piston chamber; resilient barrier modules are adapted to separate the curved piston within the curved piston chamber from first and second hydraulic or pneumatic chambers on either side of the curved piston chamber; whereby, in use, the curved piston is configured to rotate about the axle shaft upon hydraulic or pneumatic pressure being applied to at least one of the first and second hydraulic or pneumatic chambers.