The emergency bearing for a rotary machine having magnetic bearings comprises an emergency landing device including an intermediate element (9) having a large contact area with a stator element (10), the intermediate element (9) being interposed between a bearing member (1, 2, 3) and the stator element (10) fixed to the stator (15) with radial clearance (11, 13) relative to said stator element (10). A damper element (13) acting in the radial direction is interposed between the intermediate element (9) and the stator element (10), and a contact element (14) having very low friction is implemented between the intermediate element (9) and the stator element (10) to reduce friction during rotary movements between these two elements.

A gas turbine engine (10) is provided with a plurality of shafts (18, 19, 20) interconnecting its compressor portions (11, 12, 13) with its turbine portions (15, 16, 17). Each shaft (18, 19, 20) is supported in the hotter part of the engine by electromagnetic bearings (26, 28, 32) and by rolling element bearings (24, 27, 29, 31, 33) in the remainder of the engine (10). The arrangement provides a simplified liquid lubrication system for the rolling element bearings (24, 27, 29, 31, 33) which reduces the likelihood of lubricant thermal degradation of the lubricant.

Electric power is stored in a flywheel assembly, from a dc power buss, and supplied to the buss, through electronics associated with a motor/generator, its rotor integral with a flywheel supported by magnetic bearings. The power is reciprocally converted by the motor/generator, controlled by current in its polyphase stator windings, between electricity and kinetic energy. The flywheel and rotor assembly spins around a vertical axis. The rotor contains radial-field permanent magnets attached to supporting outer annular high-permeability steel, attached to inner annular steel. This completes a path for the magnets' field, which interacts with current in the stator windings, to produce torque between the rotor and the stator. Polyphase sinusoidal currents in the stator windings are controlled by the associated electronics, responsive to respective rotation angle sensors and the dc power buss voltage, with override control responsive to flywheel rotation speed, axial and radial position sensors, and operator settings. During normal operation, the flywheel assembly is levitated by axial attraction of its annular high-permeability poles near its top, to a fixed annular permanent magnet and high-permeability poles above it. The stator windings and non-rotating parts are affixed to a sealed and evacuated stationary flywheel enclosure. The flywheel assembly is released by mechanical backup bearings at startup, which then normally remain disengaged until shutdown. During normal operation, the flywheel assembly is levitated by the axial magnetic field, which also provides inherently stable centering. Axial position stability, and continuous axial position adjustment to seek and maintain axial position where force due to the permanent magnet is equal to levitated weight, is provided by a cooperative annular concentric coil whose current is controlled by an axial servo responsive to an axial position sensor. The coil adjusts strength of the magnetic field between the fixed and rotating poles, and thereby dynamically adjusts and stabilizes lift force. A coil current time-integral is combined with axial position feedback, so that average current is continuously adjusted to zero, by axial position adjustment. Radial electromagnets damp flywheel swirling at resonant vibration frequencies, stabilize its spin axis attitude at spin speeds too low for effective gyro stabilization, and constrain radial position during possible earth tremors. At normal spin rates, with the spin-axis at the rotor assembly center of mass, spin-axis verticality is stabilized by gyroscopics and leveled by gravity.

A touchdown bearing and actuator ring assembly for selectively biasing a ball bearing into direct engagement with a rotating shaft subject to significant axial thrust forces. The Actuator ring assembly includes a pair of relatively rotatable ring members abutting the bearing assembly. Confronting faces of the ring members include protuberances. As the ring members undergo relative rotation, the protuberances come into alignment, wedging-apart the ring members and biasing the bearing assembly into contact with the rotating shaft. A disengagement actuator selectively rotates the ring members in the opposite direction until the protuberances are out of alignment, allowing a restraining spring to bias the bearing assembly away from the rotating shaft. The present invention provides an assembly capable of quickly and repeatedly engaging and disengaging the touchdown bearing with the rotating shaft, using a minimum of envelop space and weight.

A drive motor has a shaft supported by a casing to be rotatable and movable in the axial direction over a predetermined stroke. A portion of the shaft is utilized in order to form a rotary motor section for rotating the shaft, and another portion of the shaft is utilized in order to form an electromagnetic plunger section for moving the shaft in the axial direction. The rotary motor section and the electromagnetic plunger section are integrally built in the casing. The drive motor is used in a drive apparatus for a pre-plasticization-type injection molding machine. The front end of the shaft is connected to the rear end of a screw disposed within a barrel of a plasticizing unit of molding machine. Through axial movement of the shaft, a resin passage of the barrel is opened and closed by a valve portion provided at the front end of the screw.