Downhole power drilling tool having multi-stage dual plunger eccentric gear mechanism

A downhole power drilling tool, comprising:

• a flow distribution shaft,
• an outer pipe, and
• a plurality of eccentric gear driving mechanisms which are coaxially arranged, wherein the flow distribution shaft is suspended and supported in the outer pipe by the plurality of eccentric gear driving mechanisms;
• each of the plurality of eccentric gear driving mechanisms defining a stage and comprising:
• a planetary gear train, and
• plunger driving structures symmetrically arranged on two axial end faces of the planetary gear train;
• wherein two pairs of planetary gears which are symmetrically distributed are arranged on a planetary carrier of the planetary gear train, a gear ring of the planetary gear train is in an interference fit with the outer pipe;
• each of the plunger driving structures comprises a mounting block, a through hole is formed in a center of the mounting block, and an inner diameter of the through hole is the same as an inner diameter of a sun gear of the planetary gear train;
• four plunger passages are formed in a radial direction of the mounting block, and the four plunger passages are uniformly distributed around the center of the mounting block;
• each of the four plunger passages is filled with a plunger in a sliding fit;
• a guide post is integrally formed in a wall of the plunger, an axial direction of the guide post is the same as an axial direction of the flow distribution shaft, and a guide groove is formed at a position corresponding to the guide post of a corresponding one of the four plunger passages;
• the guide groove facing one side of the planetary gear train is a through groove, and the guide post extends through the through groove to be in eccentric connection with one of the two pairs of planetary gears on the planetary gear train;
• and
• wherein one end of the flow distribution shaft is open, a second end of the flow distribution shaft is closed, and an inner cavity of the flow distribution shaft is a flow distribution passage;
• the plurality of eccentric gear driving mechanisms are arranged on the flow distribution shaft at intervals in the axial direction of the flow distribution shaft, the sun gear is keyed onto the flow distribution shaft;
• four rows of water inlet ports and four rows of water outlet grooves are uniformly and circumferentially formed in the flow distribution shaft, the water inlet ports are in fluid communication with the flow distribution passage, the water inlet ports and the water outlet grooves in each row are spaced apart from each other, and an angular difference between the water inlet ports and the water outlet grooves in adjacent rows is 45°;
• an angular difference between eccentric gear driving mechanisms of the plurality of eccentric gear driving mechanisms in two adjacent stages is 45°, and when the four plunger passages of one stage are in fluid communication with the water inlet ports on the flow distribution shaft, the four plunger passages of an adjacent stage are in fluid communication with the water outlet grooves.