Methods and apparatus are disclosed for automatically detecting the failure configuration of a pneumatic actuator. A control module is operatively coupled to the actuator, and the actuator is operatively coupled to a valve having a flow control member. When a number of pilot valves included in the control module is indicative of a double-acting actuator, the failure configuration of the actuator is determined based on the number of pilot valves. When the number of pilot valves included in the control module is indicative of a single-acting actuator, the failure configuration of the actuator is determined by comparing a first measurement value obtained in response to moving the flow control member in a first direction to a first position and a second measurement value obtained in response to moving the flow control member in a second direction opposite the first direction to a second position.

A rotary actuator (10) is provided with a linear activation mechanism (40a) that causes a pinion (80) to rotate, and a cylinder body (12) in which a cylinder hole (28a) is formed. The linear activation mechanism (40a) comprises a rack (42) on which a plurality of teeth (44) that mesh with the pinion (80) are provided, and pistons (48a, 48b). The pistons (48a, 48b) are each provided with a piston main body (50a, 50b) that has a shape corresponding to that of the cylinder hole (28a). Each of the piston main bodies (50a, 50b) comprises a body (52a, 52b) and an extension section (54a, 54b). The ends of the rack (42) are connected to the extension sections (54a, 54b) of the set of pistons (48a, 48b), and a space (73a) shielded from the cylinder hole (28a) is formed between the bodies (52a, 52b) of the set of pistons (48a, 48b). The linear activation mechanism (40b) is also configured similarly.

A rotary drive for actuating a valve element of a valve fitting, having a housing, which has a drive device and a pivot-mounted driven shaft which can be driven by the drive device and which can be coupled to the valve element, and a position detection device for detecting a position of the driven shaft, wherein the position detection device has a magnet module attached to the driven shaft in a torque-proof manner and a sensor module which is fitted onto or into the housing and is designed to detect a magnetic field measurement value according to the magnetic field generated by the magnet module. The the magnet module and/or the sensor module is attached such that it can be removed from the rotary drive, and the rotary drive includes a control device, which is adapted to determine if the magnet module or the sensor module is removed from the rotary drive.

A device for actuating a valve by means of a rack meshing with an elliptical pinion connected with a sleeve so that one transmits a torque to the other. The connections between the pinion and the rack as well as the sleeve are separable, so that the angular reference positions of the pinion relative to both the rack and the sleeve can be adapted according to a predefined variation in the torque required for actuating the valve.

A stepper motor driven actuator system is provided. The system includes a stepper motor, a cam, and a gearbox system. The gearbox system operatively connects the stepper motor to the cam. The cam rotates in response to stepping of the stepper motor. The system also includes a valve having a control piston located therein. The control piston is configured to translate in response to rotation of the cam. The system further includes a rotary actuator. The rotary actuator is fluidly connected to the valve, and the rotary actuator is configured to rotate the cam in response to translation of the control piston.

This disclosure provides a valve actuator that has improved durability and efficiency. The valve actuator includes a housing cylinder having a pinion centrally located, running perpendicular to the cylinder, secured at the top with a circlip, sealed with o-rings and friction reducing bearings both at the top and bottom. A pair of pistons with linear gear teeth mates to opposite sides of the pinion and seals against the cylinder's interior with o-rings and friction reducing bearings. A cam, connected to the central pinion is stopped by bolts run into the cylinder at the end of both closing and opening strokes. The body is sealed with two endcaps having internal o-rings and secured with cap screws.

A power transmission device may include a first power transmission unit configured to connect to an input portion and to receive a power from the input portion, a second power transmission unit configured to deliver the power to an output portion, and a connecting unit configured to connect the first power transmission unit and the second power transmission unit, and to deliver a pressure of a transfer fluid occurring due to the first power transmission unit to the second power transmission unit.

Embodiments of the invention provide an electro-hydraulic actuator including an electric linear actuator, a double chamber hydraulic cylinder, and a hydraulic actuator. The double chamber hydraulic cylinder includes a double chamber piston coupled to the electric linear actuator and defining a first double chamber volume and a second double chamber volume. The hydraulic actuator includes a hydraulic actuator housing, a first rack piston, a second rack piston, a rack arranged between the first rack piston and the second rack piston, and a pinion engaged with the rack. A first hydraulic actuator volume is defined between the hydraulic actuator housing and the first rack piston in communication with the first double chamber volume, and a second hydraulic actuator volume is defined between the hydraulic actuator housing and the second rack piston in communication with the second double chamber volume.

A vehicle and vehicle drive apparatus having a hydraulic pump and a first and second hydraulic motor, each disposed on a center section, is disclosed. A main housing having a housing cover contains the hydraulic pump and the first and second hydraulic motors, which in turn drive first and second motor shafts, respectively. The first and second motor shafts are enclosed in first and second motor shaft housings, respectively, and the main housing combined with the housing cover and the first and second motor shaft housings form a sealed sump. The main housing has mounted thereon a pinion shaft, a pinion gear and a steering rack meshed with the pinion gear. A first steering arm is rotatably mounted to the first motor shaft housing and connected to the steering rack and a second steering arm is rotatably mounted to the second motor shaft housing and connected to the steering rack.

The disclosure relates to a transmission unit having (i) a housing for the fluid-tight encapsulation of at least one part of the transmission unit, (ii) a rack and pinion transmission which is arranged in the housing and has at least one gear rack, (iii) a hydraulic drive system, which is arranged in the housing, has at least one displacer unit for increasing the energy of a pressurizable working fluid of the hydraulic drive system, and has at least one chamber in which a piston, operatively connected to a gear rack of the rack and pinion transmission, can be moved using the working fluid in order to effect a linear movement of the gear rack, and (iv) a rotatable mechanical actuator, which is operatively connected to the pinion of the rack and pinion transmission and is arranged outside the housing at least in portions.