Parallel Coil Spring Model for Variable Spring Constant Testing
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Solution Overview
Problem
Conventional coil spring modeling apparatuses are limited in producing a reactive force corresponding to the amount of compression, restricting the type of coil springs that can be modeled and failing to accurately simulate the characteristics of coil springs with variable spring constants.
Innovation Solution
A coil spring modeling apparatus featuring a Stewart-platform-type parallel mechanism with six hydraulic cylinders and linear displacement gauges, which detect displacement and adjust fluid pressure to produce a reactive force matching the spring constant of the actual coil spring, allowing for simulation of various coil springs and their characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a conventional coil spring is used with wire ends extending axially, then the spring can be manufactured simply, but the spring cannot be automatically fed into a coil spring press for mounting
Solution Approach 1:
Instead of extending the wire ends axially outward from the coil, the wire ends are configured to extend axially inward toward each other, forming a loop structure. This inverted configuration allows the spring to be automatically fed into the press from above, while the wire ends remain contained within the overall spring envelope, maintaining compactness.
Solution Approach 2:
The wire ends are bent back and nested within the coil structure, forming loops that fit within the spring's overall dimensions. This nesting allows the wire ends to be positioned for automatic feeding without increasing the spring's external size, and the loops can be inserted through the press opening and engaged with the mounting surface.
2Volume of moving object
If wire ends are bent back and nested within the coil, then the spring maintains a compact size, but the wire ends may contact each other causing interference during mounting
Solution Approach 1:
The wire ends are given a specific local configuration - bent back at right angles to the coil axis and forming loops with openings facing each other. This local quality change ensures the wire ends are contained within the spring envelope for compactness, while the loop structure prevents direct contact and interference between the wire ends during the mounting process.
3Ease of operation
If wire ends extend axially outward, then the spring structure is simple, but the spring occupies more space and cannot be fed automatically
Solution Approach 1:
The wire ends are configured to extend axially inward toward each other rather than outward, forming loops that contain the wire end extensions within the spring's overall envelope. This inverted configuration enables automatic feeding while maintaining a compact spring size, as the wire ends do not protrude beyond the spring's external dimensions.
Data Source
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AI summary
A coil spring modeling apparatus (20) includes a first attachment member (21) disposed on a lower spring seat (10A), a second attachment member (22) disposed on an upper spring seat (15A), an actuator unit (30) formed of a Stewart-platform-type parallel mechanism, a spring height detection mechanism (40A), a hydraulic pressure supply device (37), and a controller (70). The spring height detection mechanism (40A) is constituted of displacement gauges (401-406) such as a linear variable differential transformer (LVDT). These displacement gauges (401-406) are provided on hydraulic cylinders (311-316), and detect amounts of displacement relative to the reference lengths of the hydraulic cylinders (311-316), respectively. The hydraulic pressure supply device (37) is controlled by the controller (70) and supplies fluid pressure according to the amounts of displacement detected by the displacement gauges (401-406) to the respective hydraulic cylinders (311-316).