Wave Spring Shim Assembly for Precise Preload Adjustment
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Solution Overview
Problem
Existing torque limiting devices require iterative and time-consuming processes to accurately set the preloading force of compression coil springs, involving shim adjustments and disassembly, to ensure consistent operation.
Innovation Solution
An edge wound wave spring assembly with a shim having radially projecting mounting lugs that securely attach to the spring, allowing for adjustable preload by rotating the shim to achieve the desired axial length, eliminating the need for iterative shim adjustments and disassembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a compression coil spring with shim is used to set preloading force, then the preload can be adjusted, but the process requires iterative disassembly and machining of shims which is time-consuming
Solution Approach 1:
The invention uses an edge-wound wave spring with a movable mounting lug that can be positioned at different locations along the spring's length. By moving the mounting lug axially, the preload force is dynamically adjusted without requiring disassembly or machining, thus resolving the contradiction between precision and time consumption.
Solution Approach 2:
The preload force is adjusted by changing the axial position of the mounting lug along the spring, which modifies the effective length and stiffness of the spring. This parameter change allows precise preload setting while avoiding time-consuming iterative processes.
2Manufacturing precision
If the shim thickness is changed to adjust preload, then the preloading force accuracy improves, but the device requires disassembly and reassembly which reduces productivity
Solution Approach 1:
The mounting lug is designed to be movable along the spring's axial direction, allowing preload adjustment without disassembly. This dynamic adjustment mechanism maintains precision while significantly improving assembly efficiency and productivity.
Solution Approach 2:
The spring assembly itself provides the adjustment mechanism through the movable mounting lug, eliminating the need for external shims and their associated disassembly/reassembly operations. The system adjusts itself without requiring removal from the device.
3Device complexity
If a fixed shim is used between spring and surface, then the structure is simple, but the preload cannot be adjusted without disassembly
Solution Approach 1:
The mounting lug transitions from a fixed position to a movable position along the spring, enabling preload adjustment while maintaining structural simplicity. The adjustment mechanism is integrated into the existing spring structure rather than adding separate components.
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 precise and efficient setting of the preload force without disassembly, reducing the time and effort required to achieve the correct torque limiting characteristics in torque limiting devices and other applications.
Implementation Method 1
The edge wound wave spring comprises a plurality of axially spaced, axially compressible wave-like turns
Data Source
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AI summary
A spring assembly (50) comprises an edge wound wave spring (52) and a shim (54). The spring (52) comprises a plurality of axially spaced, axially compressible wave-like turns (56) extending between a first end portion (58) and a second end portion (58). The first end portion (58) comprises a plurality of closely arranged parallel turns (64). The shim (54) comprises a shim body (66) and at least one mounting lug (68) projecting radially from the shim body (66). The mounting lug (68) is received between adjacent turns (64) of the first end portion (60) of the edge wound wave spring (52) for retaining the shim (54) to the edge wound wave spring (52).