Waste Gate Valve Shaft Clearance to Prevent Clasp Reaction Force
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Solution Overview
Problem
The durability of turbochargers is compromised due to the reduction in coupling force of the valve shaft and clasp, leading to increased chattering sounds, as the weight of the clasp increases, causing a large reaction force that affects the waste gate valve's operation over time.
Innovation Solution
A variable-flow-rate valve mechanism with a stem, link member, attachment member, valve, and clasp configuration where the clearance between the attachment hole and valve shaft is set to be smaller than the interval dimension between the valve body and clasp, ensuring the clasp remains non-contact with the attachment member, even when the weight is increased, thus reducing the reaction force and enhancing durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the weight of the clasp is increased to reduce chattering sounds, then the chattering sound is suppressed, but the coupling force of the valve shaft and clasp is reduced over time, affecting durability
Solution Approach 1:
The patent introduces a reaction force receiving portion on the attachment member that acts as an intermediary to receive and redirect the reaction force generated when the valve body contacts the valve seat. This prevents the reaction force from being transmitted to the clasp, thereby maintaining the coupling force between the valve shaft and clasp even when the clasp weight is increased to suppress chattering sounds.
Solution Approach 2:
The patent extracts the harmful reaction force from the transmission path between the valve body and the clasp. By providing a dedicated reaction force receiving portion on the attachment member, the reaction force is separated from the clasp, allowing the clasp to be weighted for noise suppression without compromising the coupling force.
2Stability of the object's composition
If the weight of the clasp is increased to suppress valve vibration, then vibration is reduced, but a large reaction force acts on the clasp, reducing operational reliability over time
Solution Approach 1:
The reaction force receiving portion serves as an intermediary structure that intercepts the reaction force generated during valve operation. This allows the clasp to maintain higher weight for vibration suppression while the reaction force is redirected to the attachment member, preventing cumulative stress that would reduce operational reliability.
3Ease of operation
If the clearance between attachment hole and valve shaft is increased to allow valve movement, then valve followability is improved, but the clasp may contact the attachment member, increasing reaction force
Solution Approach 1:
The reaction force receiving portion on the attachment member acts as an intermediary that safely accommodates the reaction force when the valve moves within the clearance. This allows sufficient clearance to be provided for valve followability while preventing the clasp from contacting the attachment member, as the reaction force is redirected to the dedicated receiving portion.
Data Source
AI summary
A clearance δ between an inner peripheral surface of an attachment hole of an attachment tongue and an outer peripheral surface of a valve shaft is set to be smaller than an allowable displacement amount λ in an axial direction of a valve with respect to the attachment tongue. When a condition is satisfied in which the outer peripheral surface of the valve shaft comes into contact with a front-side periphery and a back-side periphery of the attachment hole of the attachment tongue, and in which a top surface of a valve body comes into contact with a back surface of the attachment tongue, a waste gate valve is constituted so that a metal washer becomes non-contact with a front surface of the attachment tongue.