An improved screw pump such as, for example, a twin screw pump is disclosed. In one embodiment, the screw pump includes a casing, first and second intermeshing rotors, and a liner positioned between the first and second rotors and the casing. In use, the liner is arranged and configured to bend and/or pivot in unison with the first and second rotors under the axial hydraulic pressure experienced by the screw pump during use. In one embodiment, the liner may be arranged and configured to include an asymmetric axial stiffness to facilitate bending of the liner. In another embodiment, the liner may be arranged and configured in multiple segments, the segments being arranged and configured to pivot to approximate the bending of the rotor shafts.

A pump body assembly, a compressor and an air conditioner. The pump body assembly includes: an upper flange. The upper flange includes a disc portion and a neck portion extending upward from the disc portion, an outer peripheral surface of the disc portion is connected with a housing of the compressor, a height a1 of the disc portion and a distance b1 between an upper end surface of the neck portion and a lower end surface of the disc portion satisfy: 0.3≤a1/b1≤0.4, and the height a1 of the disc portion and a diameter d1 of the disc portion satisfy: 0.1≤a1/d1≤0.2.

The scroll compressor comprises a fixed scroll having a fixed end plate and a fixed spiral wrap extending from the fixed end plate; an orbiting scroll (9) having an orbiting end plate and an orbiting spiral wrap extending from the orbiting end plate, the fixed spiral wrap and the orbiting spiral wrap meshing with each other to form compression chambers; a vertical drive shaft (19) having a crankpin (21) at an upper end portion of the vertical drive shaft (19), the crankpin (21) including an outer circumferential surface (23) cooperating with an orbiting scroll bearing (24). The crankpin (21) includes a recess (25) formed in an axial end face (26) of the crankpin (21), the recess (25) and an upper portion (27) of the outer circumferential surface (23) defining therebetween a circumferential wall (28) extending along at least a part of the circumference of the crankpin (21), the circumferential wall (28) being deformable in a radial direction during operation of the scroll compressor.

Disclosed herein is a scroll compressor having a shaft balancer capable of attenuating vibration while preventing deformation of the rotary shaft during operation at a high speed.

According to one embodiment, a rotary shaft of a rotary compressor includes a first connection shaft and a second connection shaft. The first connection shaft has a cross-sectional shape including a first outer surface, a second outer surface, and a third outer surface. L1 represents a distance from an intersecting point located on one end side where the first outer surface and the second outer surface intersect each other to the rotation center, L2 represents a distance from an intersecting point located on an other end side where the first outer surface and the second outer surface intersect each other, to the rotation center, and L3 represents a distance from the third outer surface to the rotation center, a relationship of L1>L3≥L2 is satisfied.

The disclosure herein relates to device, for example a gear pump, for pumping fluid. The gear pump comprises a motor for driving a rotatable drive shaft; a drive gear configured to be driven by the drive shaft; an idler gear which meshes with the drive gear; an annular magnet disposed coaxially with the drive shaft and configured to rotate therewith; and a sensor for sensing rotation of the annular magnet and generating an output signal corresponding to a rotational position of the drive shaft.

Some embodiments are directed to a positive displacement pump having an eccentric piston, comprising a tube having a first end and a second end that is terminated by a cylinder secured to a delivery zone, the tube including an intake opening and a delivery opening, a drive shaft extending between the transmission zone and the tube, a piston arranged in the delivery zone and mounted in a sliding manner at the end of the shaft, being pressed against the cylinder by an elastic presser so as to prevent fluid displacement between the tube and the delivery zone when the pump is dry, and the elastic presser is provided to press the piston against the cylinder when the pump is running under load.

Disclosed herein is a scroll compressor having a shaft balancer capable of attenuating vibration while preventing deformation of the rotary shaft during operation at a high speed.

In the two-cylinder hermetic compressor, a main bearing is disposed on one surface of a first cylinder, an intermediate plate is disposed on another surface of the first cylinder, the intermediate plate is disposed on one surface of a second cylinder, and an auxiliary bearing is disposed on another surface of the second cylinder. A shaft is constituted by a main shaft portion which has a rotor attached thereto and is supported by the main bearing, a first eccentric portion having a first piston attached thereto, a second eccentric portion having a second piston attached thereto, and an auxiliary shaft portion supported by the auxiliary bearing. A thrust receiving portion is provided on a side of the second eccentric portion facing the auxiliary shaft portion, and the auxiliary bearing is provided with a thrust surface on which the end face of the thrust receiving portion slides while contacting therewith. The thrust surface is provided with a ring groove.

A compressor crankshaft assembly includes a crankshaft and an eccentric drive pin extending from one end of the crankshaft. The shape of the drive pin viewed into the exposed end of the drive pin is defined by the intersection of a first cylinder that is coaxial with the axis of a substantially cylindrical orbital bearing journaled and installed to receive the eccentric drive pin and a second cylinder that is coaxial with the axis of a substantially cylindrical main bearing journaled and installed to rotatably receive the crankshaft, such that the area defined by the intersecting portion is less than the area defined by either cylinder.