A blower assembly includes, but is not limited to, a blower housing defining a blower chamber and including a gas inlet and a gas outlet; a first rotor positioned within the blower chamber and adapted for rotation therein, the first rotor including a first shaft and at least two lobes defining a first lobe profile; and a second rotor positioned within the blower chamber and adapted for rotation therein, the second rotor including a second shaft and at least two lobes defining a second lobe profile, wherein the first and second rotors are formed from a metal having a coefficient of thermal expansion from about 1 (10.sup.-6 in/in * K) to about 13 (10.sup.-6 in/in * K), and wherein at least one of the outer surface of the first rotor, the outer surface of the second rotor, or the blower chamber includes a coating.

An oil pump includes: a first core in which an inner rotor having external teeth and an outer rotor having internal teeth are housed; a housing having a recess in which the first core is held; a second core disposed in contact with the first core in an axial direction; and a cover having a holding hole in which the second core is held. The first core has a first recess/projection portion formed on a first axial end surface at a side opposite to an axial end surface opposing a bottom wall of the recess. The second core has a second recess/projection portion formed on a second axial end surface that is in contact with the first axial end surface. A gap is formed between opposing surfaces of the housing and the cover in a state where the first and second axial end surfaces are in contact with each other.

Provided is a gear pump device that enables improvement in volumetric efficiency and manufacturability, and also makes it possible to ensure sealing property and to reduce drive torque. According to the present invention, a sealing mechanism is provided with an annular rubber member, an outer member, and an inner member, wherein: the inner member has, at an end of an outer peripheral wall on the side of an inner gear in the axial direction, a notch which is recessed radially inward of the inner gear so as to form, together with an axial one end face of the inner gear, a depressed part; and the outer member has an insertion part which is disposed within the depressed part and which abuts against the axial one end face of the inner gear so as to constitute a part of a sealing surface on the other side.

A screw pump, including a housing with a running bore having at least two intersecting bores, each of which receives a spindle, wherein the spindles have worm screw profiles which intermesh in portions and in operation bend in a defined bending direction under a hydraulic bending pressure, wherein each bore is configured as a slot with a longer first axis of symmetry and a shorter second axis of symmetry standing orthogonally thereto, wherein the longer first axis of symmetry runs in the bending direction.

The pump device includes a motor portion that includes a shaft rotating about a central axis and a pump portion that is driven by a motor portion via the shaft. The pump portion includes a pump rotor that rotates along with the shaft and a pump housing that includes an accommodation portion that accommodates the pump rotor. The pump housing includes a pump body that includes a first bearing portion that supports the shaft and a pump cover with an accommodation portion disposed between the pump cover and the pump body. The pump cover includes a flow path through which oil is discharged and suctioned, and includes a second bearing portion that rotatably supports the shaft and that communicates with the flow path. An end portion of the shaft on one side in the axial direction is disposed at the second bearing portion or inside the flow path.

Technologies are generally described for clearance adjustments in twin-screw pump assemblies. A twin-screw pump assembly may include a conically shaped portion of a drive shaft enveloped by a bushing. For clearance adjustment, both clamping nuts of the drive shaft, which provide pretention to the bushing and secure an axial position of a threaded screw to the drive shaft, may be removed on the flow side of the pump assembly and the bushing loosened to adjust the angularity between bushing and drive shaft. The bushing may then be pushed over the conically shaped portion and both clamping nuts re-assembled. In some examples, a clamping nut of the driven shaft may be designed and used as removal/loosening tool for the drive shaft bushing.

A scroll compressor includes a casing, compression mechanism housed in the casing, and drive shaft. The compression mechanism includes fixed and movable scrolls, and a housing. The housing includes a bearing portion configured to rotatably support the drive shaft, a body portion continuous with the bearing portion and extending radially outward, a pressing portion provided radially outside the body portion to press the casing, and a supporting portion extending from a face of the body portion near the fixed scroll. An end face of the supporting portion near the fixed scroll is a fastening face to which the fixed scroll is fastened. A gap is formed between an inner peripheral surface of the casing and outer peripheral surfaces of the body and supporting portions. An axial length of the gap is greater than or equal to an axial length of an inner peripheral surface of the supporting portion.

A blower assembly includes, but is not limited to, a blower housing defining a blower chamber and including a gas inlet and a gas outlet; a first rotor positioned within the blower chamber and adapted for rotation therein, the first rotor including a first shaft and at least two lobes defining a first lobe profile; and a second rotor positioned within the blower chamber and adapted for rotation therein, the second rotor including a second shaft and at least two lobes defining a second lobe profile, wherein the first and second rotors are formed from a metal having a coefficient of thermal expansion from about 1 (10.sup.−6 in/in*K) to about 13 (10.sup.−6 in/in*K), and wherein at least one of the outer surface of the first rotor, the outer surface of the second rotor, or the blower chamber includes a coating.

The present disclosure provides a rotary device and a rotary system, to which a press-actuated gate valve mechanism is applied. In the rotary device and the rotary system, a pressure fluid chamber is disposed on an outside of a gate valve groove so that an action of a gate valve is controlled by means of a fluid pressure. Based on the rotary device and the rotary system, the present disclosure also provides a fluid motor, a compressor, a pump and a compressor corresponding to the rotary device and the rotary system.

Disclosed herein is a scroll compressor that includes a first bearing rotatably supporting a rotary shaft relative to a casing at one side of the rotary shaft with respect to a motor, a second bearing rotatably supporting the rotary shaft relative to the casing at the other side of the rotary shaft with respect to the motor, and a third bearing rotatably supporting the rotary shaft relative to an orbiting scroll at the opposite side of the first bearing with respect to the second bearing, wherein the distance between a first bearing center and a third bearing center may be a predetermined distance, the distance between a motor center and the third bearing center may be longer than the distance between the motor center and the first bearing center, and the distance between a second bearing center and the motor center may be longer than the distance between the second bearing center and the third bearing center. Thus, it is possible to prevent the damage of the second bearing under poor load conditions.