A method for forming drilled cast which includes drilling with a drill so as to provide communication with a cast hole includes a casting step and a drilling step. The casting step is to cast a cast having a cast hole which includes a flat inner wall surface in which width of a position to be drilled with the drill is obtained by adding first length H1 serving as a manufacturing error range of the cast to a diameter D of the drill, which is a second length H2. The drilling step is to form a through hole providing communication between an interior of the cast hole and an exterior of the cast through the flat inner wall surface with the drill.

A stator and a method of manufacturing at least a portion of a progressive cavity motor or pump include disposing a cylindrical shell within a cylindrical housing, disposing a stator mold within the cylindrical shell, disposing an elastomeric material between the stator mold and the cylindrical shell, removing the stator mold from within the elastomeric material, thereby forming an elastomeric material layer having a stator profile within the cylindrical shell, and removing the cylindrical shell from within the cylindrical housing, thereby forming a cartridge having the elastomeric material layer disposed within the cylindrical shell.

An oil-free screw compressor includes: a casing having a rotor chamber; a bearing supporting rotary shafts of the screw rotors; a shaft seal device including an oil seal portion and an air seal portion; an atmosphere open hole formed in the shaft seal device; at least one communication hole formed in the rotary shaft; and an annular space communicating the atmosphere open hole with the at least one communication hole communicate with each other. The annular space includes an inner peripheral annular space formed on an inner peripheral side of the casing. Assuming an open cross-sectional area of the inner peripheral annular space as S1, a total open cross-sectional area of the communication holes as S2, an open cross-sectional area of the i-th communication hole out of the communication holes as S2i, and the number of communication holes as n (n being a natural number of 1 or more), a following relationship is satisfied. $S1S2=\underset{i=1}{\overset{n}{.Math.}}S2i$

An electromagnetic actuating device for a torque transmission system includes a shell arranged around an axis X, the shell being fixed relative to the axis X. The shell includes walls defining an annular cavity which houses a coil and at least partially a plunger which is able to move axially along the axis X to actuate a coupling device.

The present invention recites a method of fabricating a stator for a downhole motor, the method comprising the steps of providing a stator tube having an interior surface and applying a bonding agent to the interior surface of the stator tube. Additionally, a mandrel is positioned within the stator tube, the mandrel having an outer geometry that is complimentary to a desired inner geometry for the stator. Furthermore, a reinforcing material is introduced into the stator tube to fill space between the mandrel and the interior surface of the stator tube and subsequently solidified to bond the reinforcing material to the interior surface of the stator tube. The mandrel is then removed from the bonded stator tube and reinforcing material such that a stator is fabricated.

A transverse internal gear pump 1 having a trochoid 4, in which an inner rotor 3 having a plurality of outer teeth is rotatably accommodated within an outer rotor 2 having a plurality of inner teeth, the inner rotor being rotatably accommodated within the outer rotor in an eccentric state and with the outer teeth and the inner teeth meshing, and in which an intake-side volume chamber for taking in a liquid and an ejection-side volume chamber for ejecting liquid taken into the intake-side volume chamber are formed between the inner teeth and the outer teeth; a liquid intake nozzle 9 extending in a non-perpendicular direction with respect to the trochoid rotation surfaces and having a distal end immersed in a liquid reservoir 18; a pump casing 5 in which a recessed portion 5a for accommodating the trochoid is formed; and a pump cover 6.

A supercharger rotor with reduced rotational inertia may result in increased performance of a supercharger. The rotor may include composite material and may be extrusion molded, injection molded, or otherwise molded or laid-up. In certain embodiments, the rotor may include a core with a central portion and one or more radially extending portions. The core may be extruded or formed of stacked sheets. A molded portion of the rotor, including one or more lobes, may be molded over a corresponding one of the radially extending portions. In other embodiments, a main portion of the rotor includes one or more lobes but no central hole nor a corresponding shaft extending between ends of the main portion. Instead, stub shafts are attached to the ends of the main portion. The increased performance may include decreased noise, decreased cost, increased reliability and/or durability, increased thermal efficiency, an increased power-to-weight ratio, etc.

A method of casting a rotor using a cavity and core mold allows a longitudinal slot oriented transversely to the axis of rotation to be finish ground to high precision and tight tolerances by casting the slot to have a wider section which extends from the axis to a radius greater than the radii of the hubs of the rotor, and a narrower section which extends from the wider section to the outer surface of the rotor. The geometrical relation of the slot sections to the hubs as cast permits the grinding step to be performed without forming a leak path in either of the hubs.

An internal gear pump integrally provided with a plain bearing requiring fewer machining steps, allowing inexpensive manufacture, and offering a highly stable seizing property. The internal gear pump has a trochoid (4), in which an inner rotor (3) having a plurality of outer teeth is eccentrically and rotatably accommodated in an outer rotor (2) having a plurality of inner teeth, the outer teeth meshing with the inner teeth, and in which a suction-side chamber for suctioning liquid and a discharge-side chamber for discharging the liquid that has been suctioned into the suction-side chamber are formed between the inner teeth and outer teeth; a drive shaft (9) fixed to the inner rotor (3); a casing (5) in which is formed a recess (5a) for accommodating the trochoid (4); and a cover (6) for closing off the recess (5a) of the casing (5).

An electric pump includes a pump portion including a pump housing and a gear pump which is housed in the pump housing, the pump portion suctioning and discharging a hydraulic fluid by a rotation of the gear pump. The electric pump also includes a motor portion arranged adjacent to the pump portion in a direction along an axis of the pump portion and including a rotor which rotates synchronously with the gear pump and coaxially with the axis, the motor portion including a stator which is arranged at an outer periphery of the rotor and disposed coaxially with the axis, the stator applying a rotation drive force to the rotor. The electric pump further includes a resin portion integrally surrounding at least an outer periphery of the pump housing and an outer periphery of the stator.