A rotor and/or stator dampening system includes a stator and/or rotor with a liner selected of one or more materials to achieve a desired dampening effect. In one implementation, a progressive cavity motor or pump includes a stator with an internal axial bore therethrough. The stator has a liner along an axial length thereof with an inwardly facing surface defining the internal axial bore therethrough. The liner has a plurality of axial sections with at least two of the plurality of axial sections being constructed of different materials. A compression resistant mechanism, such as a spring or spring-like device, is disposed within at least one of the axial sections of the liner. The progressive cavity motor or pump also includes a rotor that is disposed and is rotatable within the internal axial bore of the stator to form a moving chamber between the rotor and the stator.

An engine includes side plates and inner plates, cylinders installed inside the side plates and the inner plates, having a piston compression chamber, and having an inverted triangular shape and an equilateral triangular shape, an integrated crankshaft rotatably installed to pass through central regions of the inner plates and having crank-eccentric shafts eccentrically formed at both ends thereof, eccentric cams installed in the crank-eccentric shafts as eccentric driving holes and positioned in the piston compression chamber, elliptical rotor pistons rotatably installed on outer peripheral surfaces of the eccentric cams as eccentric cam bearings and eccentrically rotated in opposite directions, and eccentric cam eccentric shafts integrally formed at both ends of the eccentric cams and rotatably connected to an eccentric shaft bearing of a rear eccentric shaft and an eccentric bearing of an output shaft.

Apparatus and associated methods relate to a modular rotary engine with a rotating valve shaft assembly. The rotating valve shaft assembly controls the timing of operations that alternately load and seal compressed air in a plurality of adjacent combustion chambers and alternately unload the high-temperature, high-pressure combustion gases from the adjacent combustion chambers into one or more expansion modules. The rotating valve shaft assembly includes at least two rotating valve shafts. Each rotating valve shaft includes ports that alternately open to allow a flow of compressed air from the compression module into a combustion chamber; and close to allow the injection of fuel into the combustion chamber and ignition of the compressed air and fuel mixture. The rotation of the drive shaft of the rotary engine is powered by the expansion of expanding combustion gases that turns the expansion rotor.

Apparatus and associated methods relate to a modular rotary engine with a rotating valve shaft assembly. The rotating valve shaft assembly controls the timing of operations that alternately load and seal compressed air in a plurality of adjacent combustion chambers and alternately unload the high-temperature, high-pressure combustion gases from the adjacent combustion chambers into one or more expansion modules. The rotating valve shaft assembly includes at least two rotating valve shafts. Each rotating valve shaft includes ports that alternately open to allow a flow of compressed air from the compression module into a combustion chamber; and close to allow the injection of fuel into the combustion chamber and ignition of the compressed air and fuel mixture. The rotation of the drive shaft of the rotary engine is powered by the expansion of expanding combustion gases that turns the expansion rotor.

A linear energy harvesting device that includes a housing and a piston that moves at least partially through the housing when it is compressed or extended from a rest position. When the piston moves, hydraulic fluid is pressurized and drives a hydraulic motor. The hydraulic motor drives an electric generator that produces electricity. Both the motor and generator are central to the device housing. Exemplary configurations are disclosed such as monotube, twin-tube, tri-tube and rotary based designs that each incorporates an integrated energy harvesting apparatus. By varying the electrical characteristics on an internal generator, the kinematic characteristics of the energy harvesting apparatus can be dynamically altered. In another mode, the apparatus can be used as an actuator to create linear movement. Applications include vehicle suspension systems (to act as the primary damper component), railcar bogie dampers, or industrial applications such as machinery dampers and wave energy harvesters, and electro-hydraulic actuators.

The present invention relates to a multi-cylinder rotary engine having triangular cylinders. The present invention only applies to a multiple-type rotary engine having triangular cylinders and an elliptical rotor piston, from among rotary engines having various structures. Therefore, by applying a serial type of the present invention, whereas a parallel type has to be used in a multi-cylinder type engine according to the prior art, effects of addressing a rotation error during operation and improving durability are achieved because an integrated-type crank shaft, rather than a separated assembly type which is complicated and weak at a crank shaft portion, can be used. Also, in the serial-type structure, as the number of components such as parallel shafts, gears, etc. is greatly reduced, the size of the engine is also reduced to improve economic efficiency, and moreover, noise and a failure rate are lowered, which ultimately contributes to the extension of the lifespan of the engine and miniaturization of the engine. In addition, although ignition and explosion locations of the cylinders are different from each other, deformation at one side (ignition, explosion, and opposite position), which is one of the problems of rotary engines, is reduced, and thus, an effect of contributing to the extension of the lifespan of the engine is provided.

Rotary positive displacement machines based on trochoidal geometry, that comprise a helical rotor that undergoes planetary motion within a helical stator are described. The rotor can have a hypotrochoidal cross-section, with the corresponding stator cavity profile being the outer envelope of the rotor as it undergoes planetary motion, or the stator cavity can have an epitrochoidal cross-section with the corresponding rotor profile being the inner envelope of the trochoid as it undergoes planetary motion. In some embodiments, the geometry is offset in a manner that provides structural and/or operational advantages in the rotary machine.

Tapered stator designs are engineered in a positive displacement motor (PDM) power section to relieve stator stress concentrations at the lower (downhole) end of the power section in the presence of rotor tilt. A contoured stress relief (i.e. a taper) is provided in the stator to compensate for rotor tilt, where the taper is preferably more aggressive at the lower end of the stator near the bit.

A rotary fluid pressure device, such as a low-speed, high-torque gerotor motor, is provided with a valve drive shaft that is partially inserted into and engaged with a main drive shaft as the main drive shaft engages a rotating output shaft and engages a rotating and orbiting star member of a positive displacement device. The device is also provided with a drive retainer configured to retain the engagement of the main drive shaft and the valve drive shaft.

Downhole tools for earth-boring applications may include a component of a steel material and including a bore. An inner surface defining the bore may be treated with a surface treatment. The surface treatment may include a nitrided region having nitrogen diffused into the steel material and a ceramic material adjacent to the nitrided region; the ceramic material defining the inner surface. Methods of making downhole tools for earth-boring applications may involve exposing a component of the downhole tool to an elevated temperature to heat the component in a nitrogen-rich environment. Nitrogen may be diffused into a steel material of the component and a nitrided region may be formed at one or more surfaces of the component. A ceramic material may be coated on the nitrided region of the component.