Nested Press Forming for Coned Disc Spring Material Yield
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Solution Overview
Problem
The production of coned disc springs for clutch apparatuses results in low material yield due to scrap material from punching processes, leading to increased production costs, as coned disc springs with different outer diameters require different thicknesses and material usage is inefficient.
Innovation Solution
A method involving press forming to create primary and secondary coned disc springs from a single sheet, where flat or tapered portions are formed on the coned disc springs to adjust load conditions, allowing for the production of springs with varying diameters and thicknesses from a single material, thereby optimizing material usage and reducing production steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If coned disc springs with different outer diameters are produced by punching blanks from sheets of material, then various sizes of coned disc springs can be manufactured, but large amounts of sheet material are scrapped leading to low material yield
Solution Approach 1:
The patent applies nesting by punching a smaller outer diameter blank from the inner area of a larger outer diameter blank in a single press forming operation. This nested approach allows two blanks of different sizes to be obtained from one sheet, significantly improving material utilization and reducing scrap compared to producing each blank separately.
Solution Approach 2:
The patent segments the sheet material into multiple blanks of different sizes (primary and secondary blanks) within a single sheet. By dividing the material usage into hierarchical segments, the process optimizes material consumption while producing multiple components from one sheet.
2Force
If coned disc springs are made from materials of different thicknesses to achieve different loads in flat conditions, then the load requirements for different clutch structures can be met, but the production process becomes more complex
Solution Approach 1:
The patent applies local quality by forming flat portions or tapered portions at specific locations (inner peripheral portion or outer peripheral portion) of the coned disc spring. This localized structural modification allows adjustment of the load in flat condition without changing the overall material thickness, thereby meeting different load requirements while maintaining uniform material thickness across all springs.
Solution Approach 2:
The patent changes the geometric parameters of the coned disc spring by adding flat or tapered portions to modify the load characteristics. This parameter change approach allows different load capacities to be achieved through geometric variation rather than material thickness variation, simplifying the production process.
3Adaptability or versatility
If multiple punching operations are performed to produce blanks of different outer diameters, then various sizes of coned disc springs can be produced, but the number of production steps increases
Solution Approach 1:
The patent merges multiple punching operations into a single press forming step by designing a die that can simultaneously punch out both the primary blank (larger outer diameter) and the secondary blank (smaller outer diameter) from the same sheet. This consolidation reduces the number of production steps while maintaining the ability to produce various sizes.
Solution Approach 2:
The patent performs preliminary action by pre-planning the blank layout and die design to enable simultaneous punching of multiple blanks in one operation. The die is designed in advance to accommodate the nested blank configuration, allowing efficient production without requiring sequential punching operations.
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 enhances material yield and reduces production costs by enabling the production of coned disc springs with desired load conditions from a single sheet of material, improving the efficiency and cost-effectiveness of the process.
Implementation Method 1
punching plural ring-shaped blanks from the sheet of material by press forming
Implementation Method 2
The coned disc spring is elastically deformed from the dish shape into an approximately flattened shape, thereby absorbing shocks occurring during the engagement of the clutch
Data Source
AI summary
A clutch apparatus is equipped with two clutch structures having a clutch drum therein. A driven plate and a piston are provided in the clutch drum of each clutch structure, and a primary coned disc spring and a secondary coned disc spring, which are ring-shaped, are provided between the driven plate and the piston. A flat portion is formed on an inner peripheral portion of a convex surface of the primary coned disc spring, and the flat portion can come into contact with a counter member first when a load is applied. A load in a flat condition due to elastic deformation is adjusted by the flat portion so as to be a desirable value. Blanks and of the primary coned disc spring and the secondary coned disc spring can be obtained from one sheet of material having the same thickness. In this case, the flat portion is formed by press forming on an inner peripheral portion of the blank in view of the shape thereof after bending forming is performed.