Valve Device Single Spring Mechanical Stopper EGR
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Solution Overview
Problem
Conventional valve devices for exhaust gas recirculation (EGR) units require complex double-spring structures to manage valve rotation, increasing production costs and assembly complexity, and lack responsiveness when fully closed due to unnecessary speed reduction to prevent collisions with stoppers.
Innovation Solution
A valve device with a single return spring that biases the valve only in the closing direction, combined with a mechanical stopper to control rotation limits, allowing the valve to rotate on both sides of the full-close position and eliminating the need for speed reduction, thereby enhancing responsiveness and reducing production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a double-spring structure is used to control valve rotation from both plus and minus sides, then the valve can be controlled to rotate back to the full-close position from both directions, but the structure becomes complicated and production cost increases
Solution Approach 1:
The patent extracts the unnecessary minus-side control function from the spring system. By removing the second spring that controlled the minus side, the design simplifies to a single-spring system that only provides plus-side control, while the mechanical stopper handles the minus-side limitation.
Solution Approach 2:
The mechanical stopper acts as an intermediary element that replaces the need for the second spring. It physically limits the valve rotation to prevent exceeding the minus-side threshold, achieving the same control objective without the complexity of a dual-spring system.
2Ease of manufacture
If the valve rotates toward the minus side for deposit removal, then the valve cleaning function is improved, but the structure requires a double-spring system increasing assembly process
Solution Approach 1:
The patent separates the deposit removal function from the spring control system. The valve can still rotate toward the minus side for cleaning, but the mechanical stopper (rather than a second spring) defines the rotation limit, simplifying the assembly process while maintaining the cleaning capability.
3Reliability
If speed reduction control is applied to prevent valve collision with stopper, then collision prevention is improved, but the response time of the valve decreases
Solution Approach 1:
The mechanical stopper is positioned to define the minus-side threshold before the valve can collide with it. This preliminary positioning allows the valve to approach the stopper at full speed without requiring speed reduction control, as the stopper physically prevents exceeding the safe rotation limit.
4Reliability
If the valve is controlled to rotate within a limited range, then collision with stopper is prevented, but the deposit removing capability is reduced
Solution Approach 1:
The patent applies local quality by allowing the valve to rotate beyond the full-close position toward the minus side for deposit removal, but uses the mechanical stopper to locally limit the rotation at a specific threshold. This creates a localized control zone that enables cleaning while preventing damage.
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
The solution ensures high responsiveness of the valve when fully closed, reduces production costs, and prevents valve collisions with stoppers, enhancing the reliability and efficiency of the EGR unit.
Implementation Method 1
The return spring, constructed with a single spring, biases the valve only in a valve-closing direction
Data Source
AI summary
A valve device includes a valve, an actuator actuating the valve, a control unit controlling an opening degree of the valve, a return spring biasing the valve only in a valve-closing direction, and a mechanical stopper controlling a rotating limit of the valve in the valve-closing direction. The valve is defined to rotate on a plus side from the full-close position in a valve-opening direction and to rotate on a minus side from the full-close position in a direction opposite from the valve-opening direction. The mechanical stopper stops the valve at a stopper position which is set on the minus side from the full-close position, and a predetermined overshoot range is defined between the full-close position and the stopper position.