Abstract: A casing with housing space for retaining a first gear and a second gear in a condition where the tooth tips and both side surfaces slide, comprises a main casing which retains the first gear in a manner which allows rotation but restricts movement in the axial direction, and a gear holder which can move in the rotating shaft direction in the main casing and which rotatably retains the second gear. The main casing contains a biasing member which applies a biasing force to bias the gear holder to one side in the rotating shaft direction, and a piston which is acted on by hydraulic pressure and presses the gear holder on the other end side in the rotating shaft direction to counteract the biasing force. The gear holder is acted on by the hydraulic force from the piston to counteract the bias from the biasing member and moves in the rotating shaft direction according to the hydraulic force so that the engagement width between the first gear and the second gear which is retained by the gear holder is changed.

Abstract: The invention relates to a gear pump, especially for a power steering system, having a housing, a first cover and a second cover, the first cover being integrated into the housing.

Abstract: A complex dry vacuum pump including a root rotor and a screw rotor is disclosed for manufacturing semiconductors and/or displays in a vacuum state in a process chamber, and discharging gaseous material and/or by-products generated during manufacturing to the exterior of the process chamber. The pump can provide high gas compression transfer efficiency so as to form a vacuum in the process chamber and/or keep high gas compression transfer efficiency when the gaseous material and/or by-products are discharged. Balance between the root rotor and the screw rotor can prevent vibration and noise generated in the vacuum pump, and molding material associated with the pump may allow a stator coil to be separated and prevent various by-products from flowing from the vacuum pump.

Abstract: A method of pumping a gas stream containing a condensable species and a light gas and an apparatus therefore, the method comprising the steps of conveying the gas stream to a multistage vacuum pump comprising an inlet stage and an exhaust stage downstream from the inlet stage, and adding to the gas stream upstream of or at the inlet stage a purge gas heavier than said light gas to both inhibit migration of the light gas from the exhaust stage towards the inlet stage and to inhibit condensation of the condensable species within the pump.

Abstract: The variable displacement gear pump for a loading system in an industrial vehicle has main and sub gear pump portions, suction, discharge and bypass passages, and check and opening valves. The main gear pump portion has main drive and driven gears, and has suction and discharge side spaces. The sub gear pump portion has sub drive and driven gears, and has suction and discharge side spaces. The bypass passage returns hydraulic fluid in the discharge-side space of the sub gear pump portion to the suction passage. The check valve prevents hydraulic fluid in the discharge-side space of the main gear pump portion from flowing to that of the sub gear pump portion. The opening valve is used for opening and closing the bypass passage, and closes the bypass passage due to a pressure in a discharge conduit of the loading system increased by the load applied to the loading system.

Abstract: A high-performance gear pump that does not require highly accurate machining is disclosed. The gear pump includes a housing having an accommodation chamber. A drive gear and a driven gear are positioned in contact with an inner surface of the accommodation chamber. The drive shaft is loosely received by the shaft hole of the drive gear, and the driven shaft is loosely received by the shaft support formed in the housing and the cover.

Abstract: A twin screw pump includes a pair of rotors disposed inside a casing having an inlet and an outlet. Each rotor includes a set of threads disposed on a portion of an outer surface of a shaft. A first bearing is coupled at a first end of the shaft and a second bearing is coupled at a second end of the shaft. The first and second bearings are not separated by one or more seals. The first and second bearings are configured for being lubricated by the liquid medium of the process fluid when the twin screw pump is in an operational mode.

Abstract: A rotary machine including: a housing; a plurality of rotor spindles aligned along three orthogonal axes; rotor blades on the rotor spindles and arranged relative to each other so that each rotor blade is in tangential sliding contact with at least two other rotor blades and forming a plurality of working chambers each having a volume which changes as the rotor spindles rotate; a gear system including a plurality of internal bevel gears on the ends of the plurality of rotor spindles and for synchronizing rotation of the rotor spindles during operation; and a central valve mechanism with the rotor spindles extending radially outward therefrom and around which the rotor blades are arranged, wherein the central valve mechanism controls flow of a fluid to at least some of the working chambers formed by the rotary blades.

Abstract: A variable displacement type gear pump has gear chambers, one of which is a specific gear chamber. A suction passage is formed in the housing so as to communicate with suction-side spaces. An outlet passage communicates with discharge-side spaces. A return passage returns the fluid discharged to the discharge-side space of the specific gear chamber to the suction passage. The return passage communicates with the suction passage at a confluence portion located upstream side of the suction-side space. An opening and closing valve opens the return passage in a small displacement operational state. A check valve is located between the discharge-side space of the specific gear chamber and the outlet passage for preventing the fluid discharged from the gear chamber other than the specific gear chamber from flowing into the discharge-side space of the specific gear chamber in the small displacement operational state.

Abstract: A gear pump for an axle assembly circulates lubricating fluid from a reservoir to a fluid cooler external to the axle assembly. The gear pump includes a first housing section and a second housing section and a center section located between the first and second housing sections. An input gear mounted on an input shaft is engaged with a reduction gear, which are located in a first housing section. Two pumping gears are located in the second housing section. The center section serves as a wall and separates the first housing section from the second housing section. The gear ratio between the input gear and the reduction gear is such that the pumping gears rotate at a speed between at about 47% and at about 75% of the speed of the input shaft.

Abstract: A motor direct drive air pump comprises a housing, a first shaft, and a second shaft. The housing is formed with a left space and a right space; one of the spaces is a compression chamber having an air inlet and an air outlet; the other space has a transmission chamber and a driving chamber; stators are disposed in the driving chamber. A first shaft is disposed through a central partition of the housing; a first impeller is embedded at a portion of the first shaft located in the compression chamber, while a first gear is embedded at a portion of the first shaft located in the transmission chamber, and rotors are embedded at a portion of the first shaft located in the compression chamber.

Abstract: The invention relates to a rotor for a positive displacement rotary pump. The rotor comprises a hub with an aperture and a centre axis through said aperture and at least 2 lobes radially extending from said hub and in a direction essentially perpendicular to the axis of said hub. The rotor comprises a core of a first polymer material and a cover of a second polymer material, which second polymer material has a hardness which is lower than the first polymer material. The first and the second polymer materials are connected to each other. The hub or the major part of the hub is preferably provided by the core, whereas at least a part of the lobes is provided by the cover. The invention also relates to a method of providing the rotor and a pump comprising the rotor. The rotor has a high durability and provides an excellent sealing towards inner surface sections of the pumping house as well as towards an engaged rotor.

Abstract: The object of the invention is to provide a screw type fluid machine in which leak of gas is kept in constant, in other words, in which a gap between the screw rotors is kept substantially in constant in a discharging chamber during operation.

Abstract: An oil-free fluid machine unit is provided of which the fluid machine has two or more rotors and torque transmission between the rotors can be performed without a need of using lubrication oil thereby eliminating contamination induced by lubrication oil and without reduction of longevity of the synchronizing gears. The drive shaft 12 of the drive motor 11 is connected to the rotor shaft 14 of the fluid machine, synchronization gears 18 and 19 are attached to the rotor shafts 14 and 15 at the motor 11 side end of the rotor shafts respectively, and pulleys 16 and 17 are attached to the rotor shafts 14 and 15 at the other side ends respectively opposite to the motor 11 and a belt is looped over the pulleys so that the pulleys are rotated in counter direction to each other. At least one of the synchronization gears is made of plastic material. Thus, torque transmission between the rotors is done in two ways, via synchronization gear drive and belt drive.

Abstract: A compressor (20) has a housing (22) having first (52) and second (48) members. A motor (24) within the housing (22) is coupled to one or more working elements (26, 28) to drive the one or more working elements (26, 28) to compress a fluid. A number of electrical terminals (104) are each mounted in an associated aperture (132) in the second housing member (48) and electrically connected to the motor (24).

Abstract: A three-gear type gear pump or double gear pump wherein the first driven gear and the second driven gear are opposed to one another with the driving gear disposed between them, wherein the number of teeth of the driving gear is greater than the number of teeth of each of the first driven gear and the second driven gear.

Abstract: A drive mechanism for a bicycle comprising a pump unit driven by the rotation of the bicycle pedals, a hydraulic motor driven by the pump unit, a conduit system creating a closed hydraulic system for circulating hydraulic fluid between the pump unit and the hydraulic motor, and a pressure regulator for controlling the flow of hydraulic fluid from the pump unit to the hydraulic motor and thereby controlling the speed at which the bicycle is propelled. The pump unit has a first gear assembly having teeth with a face width w.sub.1 and a whole depth d.sub.1 and the hydraulic motor has a second gear assembly having teeth with a face width w.sub.2 and a whole depth d.sub.2. The teeth upon the respective gear assemblies mesh together to form inter-tooth pockets which facilitates hydraulic fluid transfer about the closed hydraulic system. The rotary motion relationship between the first and second gear assemblies of the present invention, as defined by their respective teeth, may vary from approximately 2.

Abstract: Disclosed is a cam pump with two sets of driving and driven pump cams, which receive polymer melt from an extruder and exit the polymer melt through two exit channels in a sequence of 1/2 volume unit, followed by a 0 volume unit, followed by 1 volume unit for one exit channel and simultaneously in a sequence of 1/2 volume unit followed by a 1 volume unit, followed by 0 volume unit for the second exit channel. The cam pump is used in a apparatus for melt mixing and spinning synthetic polymers for the manufacture of yarns with a multiplicity of bundles of filaments, whereby the properties of all filaments in all bundles alternate along their length and the properties of the filaments of each bundle of adjacent bundles alternate between the adjacent bundles.

Abstract: A rotary pump having a plurality of rotor structures disposed in a pump casing, each structure having a rotor disposed in a casing, a hollow drive shaft each for driving said rotor, a headed bolt disposed within the hollow drive shaft for attaching said rotor to the drive shaft, an internally threaded rotor shaft being attached to the rotor and having said bolt threaded therein, the rotor shaft being disposed within an enlarged diameter hollow end of the hollow drive shaft, and the head of the bolt is disposed at the end of the hollow drive shaft opposite to its end to which the rotor is attached, whereby no rotor attaching means are employed on the face of the rotor opposite to the rotor shaft, and the pump casing has a flat rotor cover over the rotor structures, without any substantial spaces between the rotor cover and the rotors.

Abstract: Two essentially identical oval shaped blades each attached rotatably by axles within a cylindrically shaped main chamber of a housing. Each blade has a cross-sectional profile approximating opposing larger radius 90 degree arcs connected by opposing smaller radius 90 degree arcs. Each blade is attached to a rotatable carriage assembly within the housing, and 180 degrees apart in the same orbital path about the rotational axis of the carriage assembly. The rotational axis of the carriage assembly, and the orbital path of the blades about the carriage assembly axis are eccentric relative to the center of the main chamber. A transmission and timing arrangement communicates and coordinates rotational movement between the carriage assembly and blades. The blades are positioned with the length of one blade perpendicular to the other blade length while rotating and orbiting about the axis of the rotating carriage assembly.

Abstract: A pump or motor comprising a casing, housing at least one rotary member and having an inlet port and an outlet port, cam means rotatable by said member and a fluid displacement device which is driven by the cam means and which includes at least one reciprocable element. This element, upon rotation of said member through each revolution, so repeatedly projects into a chamber in the casing which is in communication with one of said ports as to effect a series of momentary decreases in the effective volume of that chamber and the element is also so repeatedly retracted from that chamber as to effect a series of momentary increases in the effective volume of the chamber. In this way momentary flow of fluid is caused repeatedly to occur out from, and back into, the chamber thereby substantially reducing pulsation of flow through the pump or motor, and also attendant noise, during operation.

Abstract: An arrangement for aligning a drive shaft of a fluid-operated gear machine having a cover enclosing a housing of the machine is provided. The aligning arrangement includes a plate connected to the axial end face of the cover, which side is directed to a pair of meshing gears mounted within the housing of the machine. This plate is formed with an opening receiving the drive shaft without a play when the cover is placed in a position in which it sealingly closes the housing.

Abstract: A gear machine, such as a gear pump or gear motor, has a housing in a chamber of which there are journalled two gears which mesh with one another. One of the gears is mounted on a drive shaft the end of which is extended outwardly from the housing. The housing is closed at one side thereof with a cover having a stepped bore for receiving the end portion of the drive shaft. The cover is formed with a circumferential projection concentric with the drive shaft and adapted for centering the cover relative to an external element to be coupled with the gear machine. The stepped bore provided in the cover forms a chamber in which a centering ring with a certain radial play is positioned, which centering ring surrounds the drive shaft. A sealing ring is also positioned in the chamber formed in the stepped bore, which sealing ring sealingly closes the housing. The centering ring provides for reliable aligning of the gear machine to the external element adapted to be coupled with the machine.