Deformable Shim Bearing Stack Assembly
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Solution Overview
Problem
The existing methods for clamping inner and outer bearing races in down-hole drilling motors are time-consuming and prone to errors, requiring precise shim selection and assembly procedures to ensure proper axial clamping force, which can lead to uneven load sharing and premature failure of ball bearings due to relative rotation and wear between races.
Innovation Solution
A bearing assembly method using a deformable shim that follows a deformation curve with a plastic deformation component, allowing for adjustable compressive loads between inner and outer races, eliminating the need for precise shim selection by applying axial thrust through threaded connections and ensuring consistent clamping forces across the bearing stack.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If precise shim selection and assembly procedures are used to ensure proper axial clamping force, then bearing race clamping accuracy is improved, but assembly time and complexity increase significantly
Solution Approach 1:
The patent uses a deformable shim that is intentionally designed to be crushed during assembly, serving its purpose once and then discarded or deformed permanently. This disposable approach eliminates the need for precise shim selection and measurement, as the shim's deformation provides self-adjusting clamping force without requiring complex assembly procedures or precise tolerances.
Solution Approach 2:
The patent changes the physical state of the shim from rigid to deformable, allowing it to undergo plastic deformation under compression. This parameter change enables the shim to automatically adjust to the correct clamping force through its deformation characteristics, eliminating the need for precise dimensional control and complex assembly procedures while maintaining accurate axial clamping force.
2Adaptability or versatility
If multiple shims are used to adjust axial clamping force for inner and outer races, then clamping force adjustment capability is improved, but device complexity and error risk increase
Solution Approach 1:
The patent extracts the adjustment capability from multiple separate shims and concentrates it into a single deformable shim. By removing the need for multiple shims and their associated selection and assembly steps, the device complexity is reduced while maintaining the ability to achieve proper clamping force through the shim's controlled deformation during assembly.
Solution Approach 2:
The deformable shim serves multiple functions simultaneously: it acts as a spacer, a force distributor, and a self-adjusting element. This multi-functional design eliminates the need for multiple separate components and assembly steps, reducing device complexity while maintaining comprehensive clamping force adjustment capability for both inner and outer bearing races.
3Measurement precision
If tight tolerances on shim width (e.g., 0.005 inches) are used, then clamping force accuracy is improved, but manufacturing precision requirements and assembly difficulty increase
Solution Approach 1:
The patent changes the shim from a precision-critical component to a deformable element whose final clamping force is determined by its deformation characteristics rather than its initial dimensional precision. This allows the shim to be manufactured with much broader tolerances, as the actual clamping force is established during assembly through controlled crushing and deformation, not through precise pre-manufacturing dimensions.
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 method simplifies the assembly process, reduces the risk of errors, and ensures consistent axial compressive stresses across the bearing stack, improving load sharing and extending the lifespan of the ball bearings by maintaining proper clamping forces with a larger tolerance range, thus reducing assembly time and improving accuracy.
Implementation Method 1
a deformable shim that follows a deformation curve having at least a plastic deformation component when compressed across the predetermined range of compressive loads
Data Source
AI summary
There is provided a method of assembling a bearing assembly, having the steps of mounting a bearing stack on an inner mandrel, the bearing stack having a plurality of inner and outer races, compressing the plurality of inner races between first and second inner shoulders to within a predetermined range of compressive loads, the first and second inner shoulders being carried by the inner mandrel, inserting the inner mandrel and bearing stack into an outer housing, compressing the plurality of outer races between first and second outer shoulders to within a predetermined range of compressive loads, the first and second outer shoulders being carried by the housing, wherein at least one of the first outer shoulder and the second outer shoulder comprises a deformable shim that follows a deformation curve having at least a plastic deformation component when compressed across the predetermined range of compressive loads.