Rolling Element Cam Mechanism for Downhole Axial Actuation
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Solution Overview
Problem
Current downhole drilling tools face challenges in efficiently transferring axial movement and reducing friction and wear between rotating and stationary cam surfaces, leading to increased operational costs and reduced tool lifespan.
Innovation Solution
The use of rolling elements, such as spherical members, between the rotating and stationary cam surfaces, which allows for reduced direct impact and friction, and the incorporation of a guide member to maintain the rolling elements in a fixed position, enhancing the axial movement and reducing wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If direct contact between rotating and stationary cam surfaces is used, then the structure is simple, but friction and wear increase
Solution Approach 1:
Rolling elements are introduced as intermediary components between the rotating cam surface and the stationary cam surface. These rolling elements transfer axial movement while reducing direct frictional contact, thereby decreasing wear and extending the lifespan of the cam surfaces without significantly complicating the overall device structure.
2Reliability
If rolling elements are added between cam surfaces, then friction and wear are reduced, but device complexity increases
Solution Approach 1:
The contact interface between the rotating and stationary cam surfaces is segmented by introducing multiple rolling elements. This segmentation distributes the load and reduces wear on any single point, while the modular nature of rolling elements makes them easy to incorporate and maintain, balancing complexity reduction with reliability improvement.
3Duration of action of stationary object
If rolling elements are used to transfer axial movement, then operational lifespan is extended, but device complexity increases
Solution Approach 1:
Rolling elements serve as mediators that transfer axial movement between the rotating and stationary segments. By introducing these intermediary components, the direct wear between cam surfaces is eliminated, significantly extending the operational lifespan of the downhole drilling tool while adding only a modest increase in device complexity.
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 decreases friction, abrasive wear, and stress, thereby increasing the lifespan of the cam surfaces and improving the efficiency of axial movement in downhole drilling operations.
Implementation Method 1
one or more rolling elements disposed between and in contact with the first and second radial surfaces for transferring the non-rotating segment in an axial direction upon rotation of the rotating segment
Data Source
AI summary
An apparatus including a rotating segment having a first radial surface, a non-rotating segment having a second radial surface, a housing disposed around the first and second radial surfaces, and one or more rolling elements disposed between and in contact with the first and second radial surfaces for transferring the non-rotating segment in an axial direction upon rotation of the rotating segment. The non-rotating element may be a second rotating element that rotates at a different rotational rate than the rotating element. Each rolling element moves 360 degrees along a circular path relative to the first radial surface and the second radial surface. The first or second radial surface has a tapered section. A downhole apparatus includes a power mandrel having a first end connected to a power section member and a second end having a rotating cam surface; a rotating element engaging the rotating cam surface; an anvil sub attached to a workstring, with the anvil sub having a stationary cam surface configured to engage with the rotating cam surface. Rotation of the rotating cam surface moves the anvil sub and the workstring axially within the wellbore.