Adjustable Locking Shaft-locating Device for Submersible Pumps
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Solution Overview
Problem
Current methods for axially locking components on a shaft in electrical submersible pumps require machining grooves or threads, which reduce the shaft's strength and increase manufacturing complexity and cost, and often necessitate the use of spacer sleeves for precise positioning.
Innovation Solution
A shaft-locating device comprising an outer nut and cylindrical inner collet with tapered surfaces that securely lock onto the shaft without the need for grooves or threads, allowing for axial positioning and reuse without permanent deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If snap rings or compression nuts are used to lock bearing assemblies on the shaft, then the bearing assembly can be secured in axial position, but the shaft strength is reduced due to grooves or threads
Solution Approach 1:
A collet is introduced as an intermediary component between the shaft and the bearing assembly. The collet grips the shaft's outer diameter surface and transmits axial loads, eliminating the need for grooves or threads on the shaft. This mediator preserves shaft integrity while achieving reliable axial locking.
Solution Approach 2:
The traditional mechanical system of grooves and snap rings is replaced with a friction-based gripping system. The collet uses radial compression against the shaft's outer surface to create sufficient friction and mechanical interlocking without material removal, substituting a non-invasive mechanical approach for the invasive groove-based system.
2Manufacturing precision
If grooves or threads are machined into the shaft for component location, then components can be precisely positioned axially, but the manufacturing complexity and cost increase
Solution Approach 1:
The requirement for machined features (grooves or threads) is extracted from the shaft and transferred to the collet. The shaft remains in its simple cylindrical form, while the collet incorporates the positioning functionality through its gripping mechanism and axial compression features, simplifying shaft manufacturing.
Solution Approach 2:
The collet serves multiple functions: it secures the bearing assembly axially, positions components precisely along the shaft, and eliminates the need for separate spacer sleeves. This multi-functional component reduces overall assembly complexity while maintaining positioning precision.
3Manufacturing precision
If spacer sleeves are used to position components on the shaft, then precise axial positioning is achieved, but the device complexity and manufacturing cost increase
Solution Approach 1:
The positioning function previously requiring separate spacer sleeves is merged into the collet itself. The collet's compressed state against the shaft and bearing assembly inherently maintains precise axial positioning, eliminating the need for additional spacer components and simplifying the overall assembly.
4Reliability
If traditional locking methods are used, then components are secured to the shaft, but the installation and assembly process becomes more complex and time-consuming
Solution Approach 1:
The collet is pre-configured with its gripping surfaces and compression mechanism before installation. During assembly, it simply needs to be positioned on the shaft and compressed axially, which automatically engages the locking action. This preliminary configuration of the locking mechanism simplifies the installation process while ensuring reliable securing.
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
Enables secure axial locking of components on a shaft without reducing its strength or increasing manufacturing complexity, allowing for easy installation and removal, and eliminating the need for spacer sleeves, thus simplifying the assembly process and reducing costs.
Implementation Method 1
The inner collet can include a tapered outer surface that interfaces with a tapered inner surface of the outer nut. As the outer nut is tightened, the tapered surfaces convert axial force into radial force, causing the inner collet to contract radially inward and grip the shaft.
Implementation Method 2
The inner surface of the inner collet contacts the shaft. As the outer nut is tightened and the inner collet contracts radially inward, friction between the inner surface of the inner collet and the shaft prevents relative motion, thereby locking the axial position of the bearing assembly.
Data Source
AI summary
A shaft-locating device can include a cylindrical inner collet having an engaging surface on an inner diameter and an outward-facing tapered portion on an outer surface and an outer nut, concentrically located around the inner collet. The outer nut can have an inward-facing tapered portion that engages the outward-facing tapered portion of the inner collet, causing the inner diameter of the inner collet to become smaller, thus engaging, for example, a shaft around which the inner collet is located. In embodiments, a shoulder on the inner collet can prevent axial movement of a shaft-mounted component such as, for example, a bearing.