A screw pump comprising a housing defining a chamber and two screw rotors. Wherein each screw rotor comprises a rotor shaft and at least two displacement elements connected with the rotor shaft. Each displacement element having at least one helical protrusion. One of the displacement elements is a suction-side displacement element arranged in a suction-side section of the chamber. Another one of the displacement elements is a pressure-side displacement element arranged in a pressure-side section of the chamber. The suction-side displacement element is designed tapering in the conveying direction. The clearance between the pressure-side displacement element and the pressure-side section of the chamber at least partly decreases in the conveying direction. Furthermore, a screw rotor, a method of manufacturing a screw rotor and a use of a screw pump or a screw rotor.

A bearing assembly includes a first gear shaft aligned with a first axis and a second gear shaft aligned with a second axis. The second axis is oriented parallel to the first axis. A first bearing is supported on the first gear shaft and a second bearing is supported on the second gear shaft. A coupling mechanism extends between and radially clamps the first bearing to the second bearing. The coupling mechanism is operable to restrict relative radial movement between the first bearing and the second bearing.

Provided is a two-shaft rotary pump which is capable of improving reliability and operation efficiency by preventing an exhaust gas from flowing backward into a pump as much as possible, preventing the interior of the pump form being excessively compressed as much as possible, and suppressing temperature rise in the pump. A two-shaft rotary pump in which two rotating shafts (20, 20) provided with rotors (30, 30) are supported by bearings, such that the two rotors (30, 30) are rotated in a noncontact manner with a small clearance kept therebetween and the two rotors (30, 30) are rotated in a noncontact manner with a small clearance between an inner surface of a cylinder (50) and the two rotors, and a gas sucked into the cylinder (50) and compressed is discharged from the cylinder (50), wherein an escape hole capable of letting a part of the compressed gas escape is provided in at least one of end wall portions (52) constituting both ends of the cylinder (50) and opened in the axial direction of the rotating shafts (20, 20).

Scroll compressor with a stationary, stator scroll and a movable rotor scroll and a drive to move the rotor, whereby in each position places are formed with an instantaneous minimum opening between the rotor scroll and the stator scroll whereby at each height in a minimum opening there is a local transverse internal clearance (S), whereby at least one of the stator flanks or rotor flanks comprises an adapted flank section with an initial local stator flank deviation (T.sub.0i, AT.sub.0u) or rotor flank deviation (R.sub.0i/AR.sub.0u) that is different to zero at each point when the rotor is stationary, and during nominal operation of the scroll compressor corresponding instantaneous final local stator flank deviations (T.sub.fi, T.sub.fu) or rotor flank deviations (R.sub.fi, R.sub.fU) whose absolute values are smaller.

A dry vacuum pump may include a stator which defines an internal chamber in which a rotor is rotationally mounted. A sensor is mounted to the stator and has an output connected to a processing circuit arranged to analyse the output of the sensor to determine the absolute distance between a point on the surface of the rotor and internal stator surface. The rotor to stator clearance can thus be accurately determined in real time during operation of the pump, so that the pump performance can be optimised over its serviceable life.

In the present invention, polishing lines 71f are connected to an outer circumferential high-pressure region, but are not connected to each area that is a low-pressure region. In this configuration, the polishing lines 71f are connected to the outer circumferential high-pressure region where there is high discharge pressure, so high-pressure brake fluid is introduced within the polishing lines 71f. Therefore, a pushback effect is obtained, wherein gear pumps 19 and 39 are pushed back on the basis of the high-pressure brake fluid pressure. Furthermore, the polishing lines 71f are connected to the outer circumferential high-pressure region but are not connected to each area that is a low-pressure region, so high-pressure can be maintained within the polishing lines 71f, and a reduction in the pushback effect can be prevented. Accordingly, a decrease in the loss torque reduction effect can be prevented, and the loss torque can be further reduced.

According to one embodiment, a rotary compressor accommodating an electric motor portion and a compression mechanism portion in a sealed case, wherein the compression mechanism portion comprises a cylinder, a roller, and a vane. The vane is disposed by stacking two divided vanes in a height direction of the cylinder, which is an axis direction of the rotation axis, and where a height dimension of one divided vane is H, and a minute gap between a height dimension of the cylinder and a height dimension of the two stacked divided vanes is L, a proportion of the minute gap L to the vane height dimension H per one divided vane is
0.001<L/number of divided vanes/H<0.0015.

A gear pump includes a pump casing and a gear assembly. The gear assembly includes a driving gear, a driven gear, a driving gear shaft, a driven gear shaft, and a bearing frame. The bearing frame includes a frame main body, a pair of driving side bearing portions, and a pair of driven side bearing portions. The frame main body has a pair of bearing support potions, in which the driving side bearing portion and the driven side bearing portion are provided, and a connecting portion which connects the bearing support portions. The bearing support portions and the connecting portion are integrated together as a one-piece member.

The invention relates to a two-spindle screw pump of single-flow construction, comprising a pump housing, which has a pump portion, a bearing portion and a gear portion with a gear chamber, wherein the bearing portion and the pump portion are realized separately from each other characterized in that the gearwheel and the fastening element (and thus the shaft) are mutually rotatable, so that a spacing of the flanks of the feed screws (the flank clearance of the feed screws) is adjustable, that an opening is provided on the gear portion of the pump housing, that the opening is provided with a detachable cover, that the opening is arranged such that the cover is detachable in the mounted state of the screw pump, and that the gear chamber, for the adjustment of the flank clearance of the feed screws, can be reached with the tool necessary for this purpose.

Provided is an oil pump rotor capable of improving a volume efficiency and a quietness. When a diameter of a base circle bi of an inner rotor is bi; a diameter of a first outer rolling circle Di is Di; a diameter of a first inner rolling circle di is di; a diameter of a base circle bo of an outer rotor is bo; a diameter of a second outer rolling circle Do is Do; a diameter of a second inner rolling circle do is do; and an eccentricity amount between the inner rotor and the outer rotor is e, bi=n.Math.( Di+ di) and bo=(n+1).Math.( Do+ do) hold; either Di+ di=2e or Do+ do=2e holds; and Do> Di and di> do hold. When a clearance between the inner rotor and the outer rotor is t, 0.3(( Do+ do)( Di+ di)).Math.(n+1)/t0.6 holds, provided that Di+ di=2e; or 0.3(( Do+ do)( Di+ di)).Math.n/t0.6 holds, provided that Do+ do=2e.