Disclosed is an embodiment of a dual seal arrangement for the high-speed shaft of a supercharger with a centrifugal compressor and a mechanical speed step-down transmission to the shaft. A ring located about the shaft splits the rotational speed of the shaft between two seals, so that each seal spins at a speed of roughly half the speed of the shaft. The arrangement can also be used to split the shaft speed between two bearings in the same manner. The high-speed shaft may also have a turbine attached, to form a driven turbocharger.

A centrifugal compressor includes an electric motor coupled to a low-speed shaft, an impeller, and a speed increaser. The speed increaser includes a ring member, a high-speed shaft, rollers, a speed increaser housing member, a discharge passage, and a partition. The ring member includes a circumferential wall and is rotated when the low-speed shaft rotates. The high-speed shaft is coupled to the impeller. The rollers are located between the circumferential wall and the high-speed shaft. The speed increaser housing member stores oil. The discharge passage discharges oil out of the ring member. The partition is located between the speed increaser housing member and the circumferential wall in the radial direction. Power is transmitted from the low-speed shaft to the high-speed shaft by the ring member and the rollers.

A speed increaser includes a high-speed shaft, an annular peripheral wall surrounding the high-speed shaft and rotatable with a rotation of a low-speed shaft, the peripheral wall having an inner peripheral surface and a projection extending inwardly from the inner peripheral surface in a radial direction of the high-speed shaft, and a roller disposed between the high-speed shaft and the peripheral wall and having an outer peripheral surface that is in contact with both the projection and an outer peripheral surface of the high-speed shaft. A centrifugal compressor includes the speed increaser, an electric motor driving to rotate the low-speed shaft, and an impeller mounted to the high-speed shaft.

A centrifugal compressor includes a housing, a partition separating an empty space in a housing into a speed increaser chamber and an impeller chamber, an insertion hole provided in the partition to allow insertion of a high-speed shaft, a seal located in the insertion hole to seal a boundary between the partition and the high-speed shaft, and a bearing receptacle located in the partition. The partition includes a communication passage that allows communication between a portion of the insertion hole located closer to the speed increaser chamber than the seal and the bearing receptacle.

A gas turbine engine comprises a fan rotor having fan blades received within an outer nacelle, and the outer nacelle having an inner surface. At least a portion of the nacelle inner surface extends radially inwardly to be radially inward of an outer diameter of the fan blades. The inner surface of the nacelle is formed with a trench, which extends into the inner surface to a radially outer extent that is spaced radially outward of the outer diameter of the fan blades.

A gear unit having a shaft, in particular an input shaft, a fan impeller being connected to the shaft in a torsionally fixed manner, a fan hood being connected to the gear unit housing, which at least partially encloses the fan impeller, a separation plate for separating the pressure chamber of the fan from the suction chamber of the fan being connected to the fan hood, where the separation plate has an air intake opening for the fan impeller and is situated on the side of the fan impeller facing axially away from the gear unit, the fan impeller has an upper and a lower cover disk, which are axially set apart from each other, and fan blades are disposed between the cover disks, so that channels are formed, the radial clearance of the air intake opening being disposed within, especially centrally within, the radial clearance region covered by the upper cover disk, and the air intake opening is disposed axially within, especially centrally within, the axial region covered by the upper cover disk.

A centrifugal compressor includes a partition wall that is arranged between a ring member and the bottom of a main body in a speed-increaser chamber. The centrifugal compressor further includes an introduction passage that guides oil in a stirring region to a storage region. The stirring region includes a region between the partition wall and the ring member in the speed-increaser chamber. The storage region includes a region between the partition wall and the bottom of the main body in the speed-increaser chamber. The oil that has been stirred by rotation of the ring member collides the inner circumferential surface of a speed increaser housing before flowing toward the partition wall. The oil is then guided to the storage region via the introduction passage. Since the oil stored in the storage region is unlikely to be stirred by rotation of the ring member, only a small amount of oil is stirred by the ring member.

The system comprises: a main driver configured for rotating at a substantially constant rotational speed; a rotating load configured to be driven into rotation by the main driver; a controller, for controllably adjusting a load rotational speed; a variable speed transmission, arranged between the main driver and the load and comprised of a speed summing gear arrangement having a first input shaft, a second input shaft and an output shaft; an auxiliary driver, mechanically coupled to the second input shaft of the speed summing gear arrangement. The first input shaft of the speed summing gear arrangement is drivingly coupled to the main driver. The output shaft of the speed summing gear arrangement is drivingly coupled to the rotating load. The speed of the output shaft is a combination of a speed of the main driver and of a speed of the auxiliary driver.

A variable-speed speed increaser includes: an electric driving device which is configured to generate a rotational driving force; and a transmission device which is configured to change the speed of the rotational driving force generated by the electric driving device and transmit the changed rotation driving force to a driving target. The transmission device includes: a sun gear which is configured to rotate about an axis; a sun gear shaft which is fixed to the sun gear and extends in an axial direction around the axis; a planetary gear which is configured to mesh with the sun gear, revolve around the axis and rotate about a center line of the planetary gear; an internal gear which includes a plurality of teeth aligned annularly around the axis and is configured to mesh with the planetary gear; a planetary gear carrier; and an internal gear carrier.

The present disclosure relates to a geared turbofan engine. Example embodiments include a gas turbine engine (10) for an aircraft, comprising: an engine core (11) comprising a turbine (19), a compressor (14), and a core shaft (26) connecting the turbine (19) to the compressor (14); a fan assembly (23) located upstream of the engine core (11); and a gearbox (30) that receives an input from the core shaft (26) and outputs drive to the fan assembly (23) so as to drive the fan assembly (23) at a lower rotational speed than the core shaft (26), wherein the fan assembly (23) comprises a plurality of fan blades (41) mounted around a hub (42), the fan blades (41) having blade tips defining an outer diameter of the fan assembly (23) of from around 220 cm to around 400 cm, the hub (42) comprising a plurality of slots (51) located around a rim (52) of the hub (42), each slot (51) receiving a root of a corresponding fan blade (41), the rim (52) having a minimum radial thickness between a base of each slot (51) and an internal cavity (54) within the hub (42), wherein the minimum radial thickness is within a range of around 0.5% to around 1.1% of the outer fan diameter.