A gear pump includes a pair of gears having meshed teeth. One of the gears is configured for connection to a source of drive. The gears are received within a housing. The housing has an inlet port configured for connection to a source of fluid and an outlet port. Each of the gears have a shaft rotating within the housing on a bearing on each axial side of each gear. At least one of the bearings associated with each of the pair of gears has a plurality of springs received in recesses to bias the said at least one bearing against an end face of a respective one of the pair of gears. A retention plate holds each of the plurality springs. A method of assembly is also disclosed.

A gear pump includes a pair of gears having meshed teeth. One of the gears is configured for connection to a source of drive. The gears are received within a housing. The housing has an inlet port configured for connection to a source of fluid and an outlet port. Each of the gears have a shaft rotating within the housing on a bearing on each axial side of each gear. At least one of the bearings associated with each of the pair of gears has a plurality of springs received in recesses to bias the said at least one bearing against an end face of a respective one of the pair of gears. A retention plate holds each of the plurality springs. A method of assembly is also disclosed.

A mud motor, system, and method for using same are disclosed. A mud motor can include a continuously formed power section stator housing having a first end, a second end, and an internal cavity comprising a series of stator lobes and a housing portion passing. The stator lobes can extend from the first end of the power section stator housing until a first end of a transition portion. The transition portion can form a unitary combination with the stator lobes. The mud motor further includes a rotor assembly including a power section rotor having rotor lobes to be disposed completely within the internal cavity. Additional apparatuses, systems, and methods are disclosed.

A balance shaft module includes a balance shaft for receiving a driving force from a crankshaft of an engine by a driving gear and rotating inside a balance shaft housing, an oil pump gear being geared with the driving gear to rotate along with the driving gear, an oil pump shaft having the oil pump gear press-fitted therein and rotating as the oil pump gear rotates, and an oil pump assembly mounted in the oil pump shaft and pumping oil as the oil pump shaft rotates, wherein a pair of support rings is provided at both side surfaces of the oil pump gear to support both side portions of the oil pump gear in the oil pump shaft.

A balance shaft module includes a balance shaft for receiving a driving force from a crankshaft of an engine by a driving gear and rotating inside a balance shaft housing, an oil pump gear being geared with the driving gear to rotate along with the driving gear, an oil pump shaft having the oil pump gear press-fitted therein and rotating as the oil pump gear rotates, and an oil pump assembly mounted in the oil pump shaft and pumping oil as the oil pump shaft rotates, wherein a pair of support rings is provided at both side surfaces of the oil pump gear to support both side portions of the oil pump gear in the oil pump shaft.

A longer-lasting, lower cost, more powerful, all metal, mud motor than the presently available progressing cavity type mud motors for drilling boreholes into the earth. A mud motor apparatus possessing one single drive shaft that turns a rotary drill bit, which apparatus is attached to a drill pipe which provides high pressure mud to the mud motor, wherein the drive shaft receives at least a first portion of its rotational torque from any high pressure mud flowing through a first hydraulic chamber within the apparatus, and receives at least a second portion of its rotational torque from any high pressure mud flowing through a second hydraulic chamber within the apparatus. A typical mud motor apparatus possesses two or more hydraulic chambers, each having its own power stroke, and return stroke, which act together in a controlled fashion to provide continuous power to a rotary drill bit.

An engine fuel control system includes a main pump which receives fuel from a low pressure source and delivers the fuel at a first high pressure, and a variable displacement augmenter pump which receives fuel from the low pressure source and delivers the fuel at a second high pressure. The augmenter pump has a servo-controller to vary its pump flow rate. The system includes an augmentation valve which is actuatable by an electrically operated control valve to open a flow path therethrough which diverts fuel delivered by the augmenter pump or to shut the flow path. The system includes a pressure drop control valve which senses a pressure differential between the second high pressure and a reference pressure, and controls the servo-controller to vary the pump flow rate of the augmenter pump. The pressure drop control valve spills some of the fuel delivered by the augmenter pump.

A rotary pump with a rotational direction which can be switched, including: a housing which has a pump space featuring an inlet into a low-pressure region of the pump space for a medium to be pumped and an outlet out of a high-pressure region of the pump space for the medium to be pumped; at least one rotor; at least one bearing for the at least one rotor; at least one sealing stay which axially faces the rotor and separates the low-pressure region from the high-pressure region in the rotational direction of the rotor; and a lubricant feed which feeds a lubricant from the pump space to at least the bearing, wherein the lubricant feed is formed in the sealing stay.

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.

An air ejection port for ejecting air-mixed oil is structured with a first air ejection port provided on the inner peripheral side from an inscribed circle of an outer rotor and a second air ejection port provided on the outer peripheral side from a circumscribed circle of the inner rotor, the air ejection port can have an enlarged port area as the total of area of the first air ejection port and area of the second air ejection port in a state without being in communication with either of a suction port and a discharge port, and a disadvantage that a pump chamber of a previous stroke and a pump chamber of a subsequent stroke communicate with each other through the air ejection port can be avoided.