A positive displacement pump has a casing with a central body and two closing lids, the central body being provided with two cylindrical communicating chambers, one suction pipe and one discharge pipe, and two rotors revolvingly mounted in the chambers of the central body and supported by shafts revolvingly mounted in the closing lids. The two rotors include a male rotor having only protuberances, not cavities, and a female rotor having only cavities, not teeth or protuberances.

A pump includes: a housing in which a pump chamber accommodating an inner rotor and an outer rotor is formed in a pump chamber formation surface, and an O-ring groove is formed around the pump chamber; an O-ring that is placed in the O-ring groove; and a plate that is attached to the pump chamber formation surface and closely contacts the O-ring to close the pump chamber. Inter-hole grooves connecting to an outer edge of the pump chamber formation surface are formed around the O-ring groove.

A gear assembly of a scavenge oil pump for a vehicle is provided. The assembly comprises a first pair of meshing gears comprising a first drive gear disposed about a drive shaft and a first slave gear disposed about a slave drive in parallel relationship with the drive shaft. The first drive gear and first slave gear are in rotational meshing cooperation. The assembly comprises a second pair of meshing gears comprising a second drive gear disposed about the drive shaft and a second slave gear disposed about the slave drive. The second drive gear and second slave gear are in rotational meshing cooperation. The second pair of meshing gears is disposed linearly adjacent to the first pair of meshing gears. The first pair and the second pair of meshing gears have about ⅜ of a tooth spacing relative to each other for torque transmission of scavenge oil.

In accordance with one embodiment, the gear pump comprises a first gear meshed with a second gear as well as a housing, in which the gears are supported. The housing includes a first void, which at least partly adjoins a first side surface of the first gear, and a second void, which at least partly adjoins a second side surface of the first gear. The gear pump further comprises a fluid intake channel configured to direct fluid towards the gears, wherein at least one deflector is arranged within the fluid intake such that an incident fluid flow is diverted towards the first void as well as to the second void.

Embodiments provide a rotary lobe pump for conveying a fluid medium containing solids. Two rotary lobes have rotational axes that are spaced apart from each other a minimum length distance. A housing enclosing the two rotary lobes has an inlet opening and an outlet opening, each with a continuously decreasing convergence and defined lengths.

A disposable metering pump is made of plastic for products having solid fractions. The disposable metering pump has two rotors (10) which are coupled to each other by means of gears (11), can be driven in opposite directions, and are supported in a pump housing (5). Each rotor (10) has a rotor shaft, the rotor shaft ends (15) of which are supported in the walls of the pump housing (5). Each rotor (10) has two rotor blade walls (13), which are arranged diametrically opposite on the rotor shaft. One partially cylindrical rotor blade shoe (14) is formed at each of the peripheral ends of the rotor blade walls. The rotor blade shoes (14) lie against the cylindrical inner wall regions of the pump housing (5) in a sliding and sealing manner.

A rotary working component for use in a pump, compressor, blower or the like having an impeller, rotor, fan blade or other similar component includes a metallic insert and a composite structure overmolded on the metallic insert. The metallic insert can include an aperture adapted to mount the rotary working component to a drive shaft and a fluted catenoid or truncated spherical or spheroid outer surface having smooth contours between fluted regions thereof.

An internal gear pump (100) comprises: a rotor/torque ring comprising an internally lobed (140) rotor (130) and a torque ring (120) extending beyond at least a first end (134) of the rotor; an externally lobed (160) idler (150) encircled by the rotor; a hollow shaft (190) supporting the idler; a pressure relief element (200) positioned to shift between a first condition and a second condition; and a spring (210) biasing the pressure relief element toward the first condition from the second condition. The torque ring has at least one pressure relief port (240A, 240B) positioned so that: in the first condition, the pressure relief element blocks a path from an interior volume (235) of the pump to the pressure relief port; and in the second condition, relative to the first condition the pressure relief element does not block the path.

This disclosure generally relates to an automatic bicycle, particularly to a hydraulic automatic transmission bicycle which can automatically and adaptively change gear ratios. More particularly, this disclosure relates to those hydraulic automatic transmission bicycles which use fluid pressure to change such gear ratios, and which include various hydraulic automatic transmissions which may be provided in various configurations and may operate in various methods and sequences to provide automatic and infinitely variable gear ratios.

This disclosure generally relates to an automatic bicycle, particularly to a hydraulic automatic transmission bicycle which can automatically and adaptively change gear ratios. More particularly, this disclosure relates to those hydraulic automatic transmission bicycles which use fluid pressure to change such gear ratios, and which include various hydraulic automatic transmissions which may be provided in various configurations and may operate in various methods and sequences to provide automatic and infinitely variable gear ratios.