Variable Nozzle Mechanism Wear Resistance via Localized Clearance Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Variable nozzle mechanisms in turbochargers face wear and sticking issues due to high engine speed and temperature, leading to insufficient wear resistance, especially at maximum opening, which increases manufacturing costs.
Innovation Solution
The variable nozzle mechanism minimizes clearance between annular members and levers by strategically arranging surfaces and providing recessed portions, protruding portions, and engaging portions to reduce vibrations and adhesion, enhancing wear resistance while maintaining cost-effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the variable nozzle mechanism operates at high engine speed with wide nozzle opening, then the fluid flow rate is maximized, but wear and adhesion problems occur due to strong vibrations and high-temperature exhaust gases
Solution Approach 1:
The patent applies local quality by providing a first surface on the first annular member that locally reduces clearance specifically at the position opposing the lever side facing surface when the nozzle vane is at full opening. This localized modification targets the specific wear problem area without affecting other parts of the mechanism, allowing reduced wear at the critical location while maintaining overall mechanism functionality.
Solution Approach 2:
The patent implements preliminary action by pre-positioning the first surface to minimize clearance before the mechanism operates at high speed and temperature conditions. The reduced clearance is established in advance to prevent vibrations and adhesion that would occur during wide-open operation, thereby preventing wear before it happens rather than addressing it after damage occurs.
2Reliability
If the clearance between the first annular member and lever is reduced to suppress vibrations, then wear is reduced, but the risk of adhesion increases at positions other than full opening
Solution Approach 1:
The patent uses local quality by providing different surface configurations at different locations: the first surface with reduced clearance at the position opposing the lever side facing surface for vibration suppression, and a second surface with increased clearance at other positions to prevent adhesion. This spatial differentiation of clearance characteristics resolves the contradiction between reducing vibrations and preventing adhesion.
3Ease of operation
If a valve or nozzle is used to regulate exhaust gas energy, then supercharging pressure control is achieved, but wear and sticking problems occur in the movable portions
Solution Approach 1:
The patent applies parameter changes by modifying the clearance parameter between the first annular member and lever. By changing the clearance from a uniform value to a variable value (smaller at the first surface position, larger at the second surface position), the patent optimizes both vibration suppression and adhesion prevention while maintaining the nozzle mechanism's controllability for supercharging pressure regulation.
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A variable nozzle mechanism in which a nozzle mount (31) has a first surface (61) which has a minimum clearance in a direction of an axis with respect to a lever side facing surface (901) in an opposing region facing the lever side facing surface (901) in the direction of the axis, and a second surface (71) which is disposed adjacent to the first surface (61) in a circumferential direction of the nozzle mount (31) and has a clearance in the direction of the axis with respect to the lever side facing surface (901) larger than the clearance in the direction of the axis between the first surface (61) and the lever side facing surface (901).