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.

A variable displacement vane pump has a control slide displaceable within its housing and a first control chamber and a second control chamber for receiving pressurized lubricant. A thermally adjustable control valve is provided in the housing for adjusting pump displacement based on a temperature of the lubricant. In addition to fluid communication channels in the control chambers, at least one vent port is provided in the second chamber. The control valve is configured to control pressure and fluid communication between the chambers along with the control slide. The control valve can help reduce pump displacement at lower temperatures and low engine speeds. At lower temperatures, the second control chamber can be pressurized by the first control chamber. At higher temperatures, the second control chamber can be vented through the control valve and/or the vent port, despite the position of the control slide.

A variable displacement vane pump includes: a restrictor configured to impart resistance to flow of working fluid discharged from the pump chambers; a control valve configured to introduce the working fluid which is discharged from the pump chambers to the first fluid pressure chamber as a differential pressure between upstream and downstream of the restrictor is increased, the control valve being configured to discharge the working fluid in the first fluid pressure chamber as the differential pressure between upstream and downstream of the restrictor is reduced; a suction passage configured to guide the working fluid to be sucked into the pump chambers, the suction passage being configured to always communicate with the second fluid pressure chamber; and a guiding passage configured to allow communication between the control valve and the second fluid pressure chamber, the guiding passage being configured to guide the working fluid, which is discharged from the first fluid pressure chamber to the control valve, to the second fluid pressure chamber.

A delivery element for a rotary pump is proposed which is formed in one part from a metallic material, wherein the delivery element includes at least one first surface and at least one second surface which differ from each other, at least in regions, in at least one material property. A method for manufacturing a delivery element in accordance with the invention, a rotary pump including at least one delivery element in accordance with the invention, and the use of a delivery element in accordance with the invention in a rotary pump is also proposed.

A vane pump unit assembled into a housing includes a rotor; a plurality of vanes; a cam ring; a first plate; a second plate; a connecting bar that has a first end portion fixed to the first plate, and a second end portion which protrudes from the second plate; and a clip that prevents the second plate and the cam ring from slipping out of the connecting bar. Before the clip is assembled into the housing, the retaining of the clip is positioned at least either between the first plate and the cam ring or between the second plate and the cam ring, in a place where a gap is formed. After the clip is assembled into the housing, the housing interposes the first plate, the cam ring, and the second plate in the axial direction, and the first and second plates are in close contact with the cam ring.

A rotary positive displacement pump for fluids, in particular for the lubrication oil of a motor vehicle engine (60), has a displacement that can be regulated by means of the rotation of a stator ring (12) having an eccentric cavity (13) in which the rotor (15) of the pump (1) rotates. The stator ring (12) is configured as a multistage rotary piston for displacement regulation and is arranged to be directly driven by a fluid under pressure, in particular oil taken from a delivery side (19) of the pump or from a point of the lubrication circuit located downstream the oil filter (62). The invention also concerns a method of regulating the displacement of the pump (1) and a lubrication system for a motor vehicle engine in which the pump (1) is used.

A vane pump with a pump housing in which a cam ring is constructed or arranged, and wherein a rotor is provided that is mounted in the cam ring so that it can rotate about a rotational axis , wherein the cam ring has an inner contour with a variable radius that varies between a maximum radius and a minimum radius in the circumferential direction about the rotational axis , wherein, in the radial gap between the inner contour and the rotor , a number of lift sections is constructed with pump chambers constructed in these sections, and wherein vane elements are mounted on the rotor , wherein these elements slide against the inner contour of the cam ring and limit the pump chambers in the circumferential direction. According to the invention, the radius of the inner contour varies about the rotational axis according to the function: r=r.sub.0+a.Math.sin(n.Math.φ), where r.sub.0=(r.sub.max+r.sub.min)/2, a =(r.sub.max−r.sub.min)/2, and φ=phase angle of the radius (r) between (r.sub.min) and (r.sub.max) in the direction of rotation of the rotor .

A lubricant vane pump for providing a pressurized lubricant for an internal combustion engine includes a pump housing, a pump chamber, a shiftable control ring comprising a pressure-relief-valve, a pump rotor, a pretensioning element which pushes the control ring into a high pumping volume position, a control chamber, and a pump outlet cavity fluidically connected to the control chamber. The pump chamber comprises pump compartments which rotate from a charge to discharge zone. The control ring envelops the pump chamber. The pump rotor comprises radially slidable vanes which rotate in the control ring to provide the pump chamber with the pump compartments. A high lubricant pressure in the control chamber moves the control ring into a low pumping volume direction against the pretensioning element. The pressure-relief-valve of the control ring connects or disconnects the control chamber with one of the pump compartments between the charge zone and the discharge zone.

A lubricant pump includes a housing having a shiftable control ring which radially confines a pumping chamber, an outlet chamber, a rotor, a pumping chamber pressure section, and a slide bearing. An interface between the outlet chamber and the control ring defines an outside pressure surface of the control ring. An interface between the pumping chamber pressure section and the control ring defines an inside pressure surface of the control ring. The slide bearing supports the control ring within the housing and includes a first slide bearing surface defined by the housing and which extends in a slide plane, and a second slide bearing surface defined by the control ring. An outside projection area defined by an orthographic projection of the outside pressure surface onto the slide plane is smaller than a maximum inside projection area defined by an orthographic projection of the inside pressure surface onto the slide plane.

A vane pump for providing a pressurized lubricant includes a static pump housing defining an inlet and an outlet, a shiftable control ring with at least one slide support surface, a pump rotor with rotor vanes which rotate within the control ring, and metal slide support pad(s). The control ring shifts with respect to the pump rotor to vary an eccentricity and to thereby control a volumetric pump performance. The pump housing comprises a static control ring housing body which radially surrounds and supports the control ring, and two static pump housing lids which axially support the control ring housing body and the control ring. The control ring housing body is made of plastic. The metal slide support pad(s) is fixed to the static control ring housing body and, together with the at least one slide support surface, provides a friction bearing for the control ring.