Downhole Drilling Motor Transmission Axial Load Management
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Solution Overview
Problem
Conventional downhole drilling motors experience premature wear and inefficient torque transmission due to axial thrust loads on transmission couplings, leading to binding and rough rotation movements.
Innovation Solution
The design incorporates a driven shaft with connector assemblies featuring ball bearings, slide blocks, and spherical sockets to distribute axial loads without transferring them to the bearing assembly, along with a flex-shaft and thrust bearing assembly to dissipate axial loads, reducing thrust forces on the transmission and enabling smoother operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional universal joints are used as transmission couplings, then torque translation is achieved, but axial compression loads cause the coupling to bind and rotate, leading to premature wear and rough rotation movement
Solution Approach 1:
The transmission coupling is divided into multiple independent elements: outer race, inner race, and multiple rollers. Each roller is independently positioned by keepers, allowing individual rollers to carry axial loads while others transmit torque, preventing binding and premature wear of the entire coupling assembly.
2Force
If thrust bearings are used to carry both bit weight load and hydraulic load, then load carrying capacity is improved, but the transmission coupling still experiences compression loads causing inefficiency
Solution Approach 1:
The roller-bearing transmission coupling acts as an intermediary element between the power section and drive shaft. The rollers serve as mediators that can simultaneously handle axial compression loads from thrust bearings while efficiently transmitting torque, eliminating the need for the transmission coupling to bear compression loads alone.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution reduces wear on transmission components, enhances torque transfer efficiency, and allows for more power delivery to the drill bit, improving the overall performance of downhole drilling motors.
Implementation Method 1
Ball bearings, rollers, and keepers may be positioned around an inner race in the bearing assembly and may be spaced apart to reduce friction between the rollers and the inner race
Data Source
AI summary
Power section and transmission components within a downhole drilling motor that may reduce or eliminate axial thrust loads on the transmission of the drilling motor are provided. The transmission may utilize a driven shaft coupled between two connectors that enable torque transfer to and from the transmission while allowing the driven shaft to move freely in two planes. The power section may include a rotor with a through bore and a flex-shaft disposed in the through bore. The flex-shaft may be designed to rotate with the rotor. The flex-shaft may extend beyond the length of the rotor in one direction to be centralized within a bearing assembly. The opposite end of the flex-shaft may include a load-carrying shoulder that is retained in the bottom end of the rotor.