A compressor or pump stage is provided. The compressor or pump stage at least comprising a central shaft (8) and one rotor (3), where the axis of rotation of the rotor (3) is the central shaft (8) and where the rotor comprises a number, n, of rows of impellers (5) arranged at an outer perimeter of the rotor with an axial distance between neighbouring rows of impellers (5), where n={2, 3, 4 . . . }.

A fluid-dynamic bearing system comprising a stationary bearing component (12, 16, 18) and a bearing component (14, 14a) rotatable about a rotation axis, wherein, during operation of the bearing, the stationary and rotary components are separated from each other by a bearing gap (20) filled with a bearing fluid, wherein at least one fluid-dynamic radial bearing (22, 24) and at least one fluid-dynamic thrust bearing (28) or, alternatively, at least one conical fluid-dynamic bearing are arranged along the bearing gap (20), and wherein the bearing gap (20) comprises first and second open ends sealed by a first sealing gap (34) and a second sealing gap (36). The second sealing gap (36) exclusively extends normal to the rotation axis (40).

The bearing unit comprises: a bearing housing being formed into a cylindrical shape; and a bearing section being attached in the bearing housing. The bearing housing is made of resin. Grooves and projecting stripes are formed in an inner circumferential face of a housing hole of the bearing housing and an outer circumferential face of the bearing section, and they are extended in an axial direction. The bearing section is fitted into the bearing housing from an opening part of the bearing housing, in a state where the grooves and the projecting stripes are corresponded to each other, until the bearing section contacts an inner end face of the housing hole. A retaining projection of the bearing housing, which is formed at one end of the housing hole located on the one end side of the bearing housing, is deformed to overlap an end face of the bearing section.

Provided is a slide bearing (bearing sleeve (8)), comprising an oxidized green compact in which particles (11) of metal powder are bonded to each other by an oxide film (12) formed on surfaces of the particles (11). The oxidized green compact has a bearing surface (A, B) configured to slide, through intermediation of a lubricating film, relative to a mating member (shaft member (2)) to be supported. The bearing surface (A, B) has a large number of opening portions (13a), and the large number of opening portions (13a) and inner pores (13b) are interrupted in communication therebetween by the oxide film (12).

The present invention proposes an electric blower which can strongly hold and fix a sleeve onto a frame, and eventually provide high reliability. An electric blower 1 includes a centrifugal fan 2; a shaft 9 installed integrally rotatably with the centrifugal fan 2; a sleeve 16; a bearing 17 provided in the sleeve 16 and adapted to rotatably support the shaft 9; a diffuser 6 provided with a through hole 21 in which the sleeve 16 is fixed; a recess 41 provided in an outer circumferential surface of the sleeve 16; and a stopper 43 filling a gap between the diffuser 6 and the recess 41 and adapted to harden and thereby prevent the sleeve 16 from being detached from the through hole 21.

A motor according to an embodiment of the present invention includes a rotary shaft; a rotor mounted on the rotary shaft; a stator surrounding an outer periphery of the rotor; an impeller mounted on the rotary shaft to be spaced apart from the rotor; a bearing housing positioned between the impeller and the rotor and formed with a through-hole through which the rotary shaft passes; and a gas bearing disposed in the bearing housing, wherein a thickness of the gas bearing is equal to or greater than 50% of a gap between an inner surface of the bearing housing and an outer peripheral surface of the rotary shaft and is equal to or less than 0.3 mm.

A sintered metal bearing is formed through sintering of a compact obtained through compression molding of raw-material powder. The sintered metal bearing includes chamfered portions that are respectively formed at least along outer rims of both end surfaces of the sintered metal bearing, and a dynamic pressure generating portion formed on an inner peripheral surface of the sintered metal bearing by sizing. An axial dimension of each of the chamfered portions is set larger than a radial dimension of the each of the chamfered portions, and a difference in axial dimension between the chamfered portions on one end side and another end side in an axial direction of the sintered metal bearing is set larger than a difference in radial dimension between the chamfered portions on the one end side and the another end side in the axial direction.

A rotary reciprocating drive actuator capable of increasing the size and amplitude of a movable object such as a mirror, and of stabilizing the drive performance is provided. The rotary reciprocating drive actuator includes a movable part including a rotating shaft, a fixed part supporting the rotating shaft, and a driving part that includes a coil and a core disposed on the fixed part and a magnet disposed on the rotating shaft, and rotates the rotating shaft about the axis thereof with respect to the fixed part by utilizing electromagnetic interaction. The fixed part includes first and second supports disposed so as to face each other with the magnet therebetween in the axial direction. The rotating shaft is rotatably attached to the first and second supports via first and second bearings. One of the first and second bearings is a rolling bearing, and the other is a slide bearing.

A ratio W1/W2 of a circumferential width W1 of each of inclined hill portions G2 of a radial dynamic pressure generating portion G and a circumferential width W2 of each of inclined groove portions G3 is 1.2 or larger. And when an inner diameter of a bearing member is D, the circumferential width W2 of each of the inclined groove portions satisfies 0.2D≦W2≦0.4D.

A motor includes a stationary portion including an annular stator centered on a central axis extending in a vertical direction, and a rotating portion including a magnet radially opposite to the stator, and rotatable about the central axis. The stationary portion includes a circuit board axially below the magnet and an electronic component mounted on the circuit board, the circuit board includes a board hole passing therethrough in an axial direction. The electronic component includes a component body portion including at least a portion thereof in the board hole, a first terminal portion extending in a first direction from the component body portion, the first direction being not parallel to the axial direction, a second terminal portion extending downward from the first terminal portion, and a third terminal portion extending from the second terminal portion, and joined to the circuit board through solder.