A mud motor stator or a pump comprising of a tubular outer portion; a number of lobes extending radially inwardly from the tubular outer portion, at least one of which comprises a skeletal structure and method for producing a mud motor stator or a pump comprising of placing material and bonding the material together in a pattern dictated by the design shape of the stator or pump.

A compressor includes a drive shaft having a main shaft and an eccentric portion, and a compression mechanism having a fitted tubular portion into which a fitted shaft portion of the drive shaft is fitted. The fitted shaft portion and the fitted tubular portion slide relative to each other with an oil film interposed between. The fitted tubular portion has first and second sliding surfaces formed as portions of an inner peripheral surface of the fitted tubular portion in the circumferential direction. The second sliding surface has a smaller axial width than the first sliding surface. A sliding portion between the fitted shaft portion and the fitted tubular portion has a gap adjacent to the second sliding surface into which a lubricating oil flows, and an oil retainer to keep the lubricating oil in the gap from flowing out toward an end surface of the fitted tubular portion.

Sealing in rotary positive displacement machines based on trochoidal geometry that comprise a helical rotor that undergoes planetary motion within a helical stator is described. Seals can be mounted on the rotor, the stator, or both. The rotor can have a hypotrochoidal cross-section, with the corresponding stator cavity profile being the outer envelope of the rotor as it undergoes planetary motion, or the stator cavity can have an epitrochoidal cross-section with the corresponding rotor profile being the inner envelope of the trochoid as it undergoes planetary motion. In some embodiments, the geometry is offset in a manner that provides advantages with respect to sealing in the rotary machine. In multi-stage embodiments, the rotor-stator geometry remains substantially constant or varies along the axis of the rotary machine.

A variable hydraulic pump include a rotor mounted on a pump housing of which a housing spring end is formed, a pivot pin, an outer ring rotatably coupled to the pivot pin and of which a ring spring end is formed, a spring mounted between the housing spring end and the ring spring end, a pressure chamber formed in the pump housing to push the outer ring, a plurality of vane provided to form a plurality of pockets, an input port to supply oil to the plurality of pockets and a discharge port to exhaust oil supplied to the plurality of pockets, wherein at the reference position of the outer ring, the angle between a first imaginary line connecting the center of the rotor and the pivot pin and a second imaginary line connecting the ring spring end and the pivot pin is 0 to 10 degrees.

This disclosure concerns an advanced nutating positive displacement device having a high power to mass ratio and low production cost. This device in one example forms an exemplary pump as will be discussed in detail. The examples disclosed herein are of the rotary positive displacement type, but in a class by themselves. The devices are formed by a nutating rotor having a face comprising lobes and valleys, and a fixed stator also having a face with lobes and valleys. The face of the rotor opposes and cooperates with the face of the stator. The opposing faces define chambers that change volume with rotation of the rotor.

A high-pressure fuel pump includes a drive shaft, and a vane pump and a plunger pump which are driven by the drive shaft. The vane pump is configured to supply pre-pressurized fuel to the plunger pump. The drive shaft includes a cam configured to drive a piston rod of the plunger pump such that the plunger pump alternately executes a fuel suction stroke and a fuel discharge stroke. The drive shaft further includes a shaft portion for driving a rotor of the vane pump. The vane pump is configured such that for each fuel suction stroke of the plunger pump the vane pump provides a fuel supply cycle that is advanced by a phase angle relative to the fuel suction stroke.

A vane pump sucks the hydraulic fluid from a first inlet port and discharges it into a first outlet port and, at the same time, sucks the hydraulic fluid from a second inlet port and discharges it into a second outlet port, as a rotor having a plurality of slits housing vanes and extending in a radial manner rotates. The vane pump has a first back-pressure groove that is communicated with some of the slits to supply a back pressure from the first outlet port to the corresponding vanes and a second back-pressure groove that is communicated with other of the slits to supply a back pressure from the second outlet port to the corresponding vanes. The vanes to which the back pressure is supplied from the first back-pressure groove include the vanes in pump chambers into which the hydraulic fluid is sucked from the second inlet port.

A variable displacement oil pump includes an adjustable member that is configured to shift according to changes in pressure inside a control oil chamber. The adjustable member has a long hole. A guide pin is disposed inside the long hole. The guide pin is fixed to either a housing or a cover of the variable displacement oil pump. The width of the long hole is larger at a part of the long hole farther away from a fixed end of the guide pin in its lengthwise direction than at a part thereof closer to the fixed end.

A compressor may include a non-orbiting scroll, an orbiting scroll, a driveshaft and an Oldham coupling. The orbiting scroll meshingly engages the non-orbiting scroll. The driveshaft includes a crankpin engaging the orbiting scroll and driving the orbiting scroll in an orbital path relative to the non-orbiting scroll. The Oldham coupling may include an annular body and a plurality of first keys extending from the annular body and slidably received in slots formed in the orbiting scroll. Each of the first keys may include a first post and a first cap covering at least a portion of the first post. The first posts may be integrally formed with the annular body from a first material. The first caps may be attached to the first posts and formed from a second material.

A scroll compressor is disclosed, which comprises an auxiliary discharge path capable of sufficiently making sure of a discharge area at an initial discharge stage. The compressor comprises a fixed scroll including a fixed end plate portion and a fixed wrap, and an orbiting scroll including an orbiting end plate portion and an orbiting wrap, wherein a discharge hole is formed in the fixed end plate portion, and an auxiliary discharge path for connecting a side of the orbiting wrap with a bottom surface of the orbiting wrap is provided to be communicated with the discharge hole, whereby a compressed refrigerant may be discharged through the auxiliary discharge path.