An apparatus includes a position adjustment circuit to receive a gap setpoint and a gap feedback signal corresponding to a gap width between a pair of meshing gear teeth of a first gear and a second gear. The position adjustment circuit outputs a gap adjustment signal corresponding to a difference between the gap setpoint and the gap feedback signal. The apparatus includes a motion control circuit to provide a first speed demand signal to the first motor that drives the first gear and a second demand signal to the second motor that drives the second gear, and dynamically synchronize position between the pair of meshing gear teeth such that the gap width between the pair of meshing gear teeth is within a predetermined range of the gap setpoint by adjusting at least one of the first speed demand signal or the second speed demand signal.

A single-screw compressor includes a screw rotor with a helical groove, a cylindrical wall rotatably housing the screw rotor, a gap adjuster mechanism, and a gear-shaped gate rotor having a plurality of flat gates. The gate rotor is arranged outside the wall. Some of the gates enter a space inside the wall via an opening formed in the cylindrical wall and mesh with the screw rotor. A fluid is compressed in a compression chamber defined in the helical move by the screw rotor, the gates meshing with the screw rotor, and the wall. The gap adjuster mechanism avoids contact between a front surface of the gate rotor toward the compression chamber and a sealing surface of the wall facing the front surface, by displacing at least one of the gate rotor and the sealing surface of the wall in an axial direction of the gate rotor.

A compressor may include first and second compression members, first and second bearing assemblies, a sensor, and processing circuitry. The second compression member cooperates with the first compression member to define a compression pocket. The first and second bearing assemblies rotatably support the first and second compression members, respectively. The first bearing assembly may include a bearing rotor and a bearing stator. The bearing stator may surround the bearing rotor and may include poles each having a winding. The sensor may measure a radial position of the bearing rotor relative to the bearing stator. The processing circuitry may be in communication with the sensor and may control electrical current supplied to the windings based on the radial position measured by the sensor to adjust the radial position of the bearing rotor relative to the bearing stator.

A vane pump includes: a casing forming a pump chamber therein; a rotor arranged inside the casing to rotate eccentrically with respect to the casing; and a plurality of vanes configured to rotate with the rotor and slide on an inner side surface of the casing. At least one of Formula (1): I(b/a)k and Formula (2): I(c/a)j is satisfied, where a represents a height of the pump chamber, b represents a height of the rotor, c represents a height of the vane in a rotation axis direction of the rotor, and where I represents a linear expansion coefficient of the casing in the rotation axis direction, k represents a linear expansion coefficient of the rotor in the rotation axis direction, and j represents a linear expansion coefficient of the vane in the rotation axis direction.

A fluid pump includes a stator. A rotor is rotationally operable with respect to the stator. A drive shaft extends from the rotor to a pump assembly that delivers a fluid from an inlet to an outlet. A pump housing includes an interior cavity that contains the stator, the rotor and the pump assembly. A pump cover is disposed at an end of the pump housing. The pump cover defines an end of the interior cavity. A spring assembly biases the pump cover in an axial direction toward the pump assembly.

A compressor includes a housing defining a working chamber. The housing further includes a bore and an endplate disposed toward a discharge end. The compressor further includes a rotor having helical threads, the rotor being configured to be housed in the bore, a rotor clearance, a controllable bearing supporting the rotor, and a controller configured to control the controllable bearing such that the controllable bearing moves the rotor in a manner to reduce and/or enlarge the rotor clearance.

To provide a displacement pump that can be assembled while properly maintaining side clearances. The displacement pump (100, 101, 102, 103, 104, 105) of the present invention for sucking and discharging a fluid such as gasoline vapor by changing pressure in a space constituted by an outer peripheral surface of a rotor (1) and an inner wall surface of a casing (2), comprising a side clearance adjusting member (4), rotating with respect to the pump main body (6), for moving a shaft (3) integrally formed with the rotor (1) in an axial direction of the shaft (3).

A single-screw compressor includes a screw rotor with a helical groove, a cylindrical wall rotatably housing the screw rotor, a gap adjuster mechanism, and a gear-shaped gate rotor having a plurality of flat gates. The gate rotor is arranged outside the wall. Some of the gates enter a space inside the wall via an opening formed in the cylindrical wall and mesh with the screw rotor. A fluid is compressed in a compression chamber defined in the helical move by the screw rotor, the gates meshing with the screw rotor, and the wall. The gap adjuster mechanism avoids contact between a front surface of the gate rotor toward the compression chamber and a sealing surface of the wall facing the front surface, by displacing at least one of the gate rotor and the sealing surface of the wall in an axial direction of the gate rotor.

A compressor includes a housing defining a working chamber. The housing further includes a bore and an endplate disposed toward a discharge end. The compressor further includes a rotor having helical threads, the rotor being configured to be housed in the bore, a rotor clearance, a controllable bearing supporting the rotor, and a controller configured to control the controllable bearing such that the controllable bearing moves the rotor in a manner to reduce and/or enlarge the rotor clearance.

A compressor includes a housing defining a working chamber. The housing further includes a bore and an endplate disposed toward a discharge end. The compressor further includes a rotor having helical threads, the rotor being configured to be housed in the bore, a rotor clearance, a controllable bearing supporting the rotor, and a controller configured to control the controllable bearing such that the controllable bearing moves the rotor in a manner to reduce and/or enlarge the rotor clearance.