Downhole Drive Shaft CV Joint Assembly for Low-Vibration Torque Transfer
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Solution Overview
Problem
Conventional constant velocity joints for downhole drilling applications face challenges in achieving improved performance characteristics while maintaining low manufacturing costs, as they often require high design and manufacturing costs and struggle with vibration reduction.
Innovation Solution
A drive shaft assembly with CV joints that incorporate cylindrical sector-shaped prongs and ball bearings, allowing for torque and thrust load transfer with angular offset, utilizing a housing with internal wall grooves and chambers to support the prongs and shaft, enabling omni-directional articulation and reduced vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional constant velocity joints are used for downhole drilling, then torque can be transmitted, but vibrations increase and performance deteriorates
Solution Approach 1:
The joint is divided into multiple functional elements: a first element with a first surface and a second element with a second surface, each having distinct geometric features. The segmentation allows independent optimization of each element's function - the first element handles torque transmission while the second element provides vibration damping through its complementary geometric features, thereby reducing harmful vibrations while maintaining torque transmission capability
Solution Approach 2:
Different regions of the joint surfaces are given different geometric qualities. The first surface has specific geometric features optimized for torque transmission, while the second surface has complementary features optimized for vibration reduction. This local differentiation of surface qualities allows the joint to simultaneously achieve high torque transmission and low vibration operation
2Reliability
If new joint designs are developed to improve performance, then vibration reduction and torque capability improve, but manufacturing cost increases
Solution Approach 1:
The joint surfaces utilize spherical or curved geometric features that can be manufactured using standard machining operations. The first surface and second surface employ curved profiles that are compatible with conventional CNC machining and grinding processes, avoiding the need for expensive specialized manufacturing equipment or processes while achieving the desired performance characteristics
Solution Approach 2:
The invention optimizes existing geometric parameters within conventional manufacturing capabilities rather than requiring new manufacturing technologies. By adjusting surface curvature radii, contact angles, and dimensional tolerances of the first and second surfaces, the joint achieves improved performance while remaining manufacturable using standard industrial processes
3Adaptability or versatility
If joints are designed to handle angular offset, then versatility improves, but device complexity increases
Solution Approach 1:
The spherical or curved surfaces of the first and second elements naturally accommodate angular offset between the drive shaft and driven member. The curved geometry allows the contact points to shift as the relative angle changes, providing inherent adaptability to angular misalignment without requiring complex mechanical mechanisms such as multiple bearings or articulated linkages
Solution Approach 2:
The first surface and second surface are designed to perform multiple functions simultaneously: they transmit torque, accommodate angular offset, and reduce vibrations. This multi-functionality is achieved through the complementary geometric features of the two surfaces, which work together to provide versatile performance without increasing the number of separate components or complicating the overall joint configuration
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
The solution provides a cost-effective, low-vibration drive shaft assembly capable of transferring torque and thrust efficiently across joints with angular deflection, enhancing the longevity and performance of downhole drilling systems.
Implementation Method 1
a cylindrical side wall having a plurality of ball bearings held in a plurality of circumferentially spaced pockets
Data Source
AI summary
A drive shaft assembly for a downhole drilling motor includes a drive shaft having a first end portion engaging a first housing and a second end portion engaging a second housing. The first end portion and the first housing form the first constant velocity joint and the second end portion and the second housing form the second constant velocity joint of the drive shaft assembly. Each end portion including a base surface having a pair of prongs extending away from the base surface and a cylindrical side wall having a plurality of ball bearings held in a plurality of circumferentially spaced pockets. Each housing includes a cavity to retain respective end portions of the drive shaft. An inner side wall of each housing includes a plurality of cylindrical grooves to receive the plurality of ball bearings to transfer torque. An internal wall of the housing includes a first chamber and a second chamber to receive and retain the first prong and the second prong to transfer torque and thrust loads between the shaft and the housings.