A rotor assembly of an electric machine includes a rotor body and a shaft assembly positioned at a central axis of the rotor assembly, and operably connected thereto. The shaft assembly includes a main rotor shaft operably connected to the rotor body, a center drive shaft located inside of the main rotor shaft, and a hydraulic damper sleeve located radially between the main rotor shaft and the center drive shaft. The hydraulic damper sleeve defines a plurality of cavities between the hydraulic damper sleeve and the center drive shaft. The hydraulic damper sleeve is configured to urge a fluid into and out of the plurality of cavities thereby damping relative circumferential motion between the main rotor shaft and the center drive shaft. A plurality of flow restrictors are configured to easily allow fluid into the plurality of cavities, while restricting flow of fluid out of the plurality of cavities.

A rotor assembly of an electric machine includes a rotor body and a shaft assembly positioned at a central axis of the rotor assembly, and operably connected thereto. The shaft assembly includes a main rotor shaft operably connected to the rotor body, a center drive shaft located inside of the main rotor shaft, and a hydraulic damper sleeve located radially between the main rotor shaft and the center drive shaft. The hydraulic damper sleeve defines a plurality of cavities between the hydraulic damper sleeve and the center drive shaft. The hydraulic damper sleeve is configured to urge a fluid into and out of the plurality of cavities thereby damping relative circumferential motion between the main rotor shaft and the center drive shaft. A plurality of flow restrictors are configured to easily allow fluid into the plurality of cavities, while restricting flow of fluid out of the plurality of cavities.

A fluid moving apparatus includes an electric motor having a rotor and a stator and a propeller. The rotor rotates relative to the stator on an axis to generate a rotational output. The rotational output is provided to the propeller to power the marine propulsion apparatus. The stator includes one or more coils configured to power rotation of the rotor. The one or more coils extend circumferentially around and can be coaxial on the axis. A portion of a housing of the motor extends into the aquatic environment to facilitate heat dissipation.

A rotary machine includes a seal device capable of restricting a flow of a fluid in a clearance between a stationary member and a rotational member. The seal device includes a pressure loss element mounted to the stationary member, a first non-contact type seal protruding from the rotational member toward the pressure loss element and facing the pressure loss element via a first gap, and a second non-contact type seal protruding from the stationary member toward the rotational member, facing the rotational member via a second gap, and being positioned on one side of the pressure loss element in a flow direction of the fluid. The seal device also includes a contact type seal protruding from the stationary member toward the rotational member and being disposed downstream of the pressure loss element and the second non-contact type seal in the flow direction of the fluid.

A hydrogen expander magnetic generator apparatus can include a magnetic generator to recover energy. Embodiments can utilize a permanent magnetic motor (PM) and energy conversion system (ECS) for converting energy from a rotating shaft of a turboexpander. Some embodiments can position magnets on the shaft such that the magnets are protected from exposure to hydrogen to avoid damage to the magnets. Some embodiments can include retrofitting of a pre-existing expander to remove an oil brake and replace it with an embodiment of the PM and ECS.

A stator core of an electric motor is provided with a first core block and a second core block formed by laminating a plurality of large-diameter thin plates in a reversed arrangement with respect to each other causing outer circumferential edge burrs of the large-diameter thin plates to face each other, and with a small-diameter thin plate sandwiched between the first core block and the second core block, and having an outer diameter smaller than the cuter diameter of the large-diameter thin plate.

A stator core of an electric motor is provided with a first core block and a second core block formed by laminating a plurality of large-diameter thin plates in a reversed arrangement with respect to each other causing outer circumferential edge burrs of the large-diameter thin plates to face each other, and with a small-diameter thin plate sandwiched between the first core block and the second core block, and having an outer diameter smaller than the cuter diameter of the large-diameter thin plate.

A vibrator includes a frame, a swing unit, and an elastic member. The swing unit is disposed within the frame and holds a magnet. The elastic member connects the swing unit and the frame. The swing unit is movable with respect to the frame while deforming the elastic member. The frame, the swing unit, and the elastic member are integrally molded with each other.

A drive unit includes a housing having first and second chambers. An electromotive drive is disposed in the first chamber and including a hollow rotor shaft. A transmission is disposed in the second chamber and includes an output shaft extending through the rotor shaft such that a gap is formed. The transmission further includes a gearing arrangement that operably couples the output shaft to the rotor shaft and reduces a speed ratio between the rotor shaft and the output shaft so that the output shaft rotates slower than the rotor shaft when operating. The gearing arrangement includes a first element fixed to the rotor shaft and a second element that rotates slower than the first element when operating. An annular clearance is defined between the first and second elements. An annular seal has a first portion engaging with the first element and a second portion engaging with the second element.

A drive unit includes a housing having first and second chambers. An electromotive drive is disposed in the first chamber and including a hollow rotor shaft. A transmission is disposed in the second chamber and includes an output shaft extending through the rotor shaft such that a gap is formed. The transmission further includes a gearing arrangement that operably couples the output shaft to the rotor shaft and reduces a speed ratio between the rotor shaft and the output shaft so that the output shaft rotates slower than the rotor shaft when operating. The gearing arrangement includes a first element fixed to the rotor shaft and a second element that rotates slower than the first element when operating. An annular clearance is defined between the first and second elements. An annular seal has a first portion engaging with the first element and a second portion engaging with the second element.