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. The mud motor apparatus possesses two hydraulic chambers, each having its own power stroke, and return stroke, and acting together in a controlled fashion, provide continuous power to a rotary drill bit.

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. The mud motor apparatus possesses two hydraulic chambers, each having its own power stroke, and return stroke, and acting together in a controlled fashion, provide continuous power to a rotary drill bit.

An eccentric movable vane pump includes a cylinder body, a first rotor, second rotors, and movable vanes of which the number is greater than or equal to 2. The first rotor is eccentrically disposed with the second rotors. One end of each of the movable vanes is rotatably connected to the first rotor, and the other ends of the movable vanes are rotatably connected to the second rotors. The first rotor is disposed on a main shaft. The cylinder body is provided with a fluid inlet and a fluid outlet respectively corresponding to an expansion area and a compression area of a space between adjacent movable vanes. The pump has a simple structure, high efficiency, low cost, multiple operation conditions, high stability, and a long service life, can operate in a high-speed/ultra-high speed range without being sealed by an elastic device, and has a small radial impact in operation.