Turbocharger Guide Vane Ring Conical Centering
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Solution Overview
Problem
Existing exhaust gas turbochargers with variable turbine geometry face challenges in assembly complexity due to the work-intensive process of centering and sealing the guide vane ring, which is often achieved through bolts or disc springs, and are prone to self-locking and thermal expansion issues.
Innovation Solution
The use of conical contact surfaces, with one surface on the guide vane ring and the other on the turbine casing, ensures automatic centering and sealing, while a disc spring preload is maintained constant through carefully designed cone angles, and a heat shielding plate protects the spring from exhaust gases, allowing for simplified assembly and reduced self-locking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the guide vane ring is connected via bolts with a support ring fixed between the turbine casing and bearing housing, then the guide vane ring is securely fixed, but the assembly process becomes work-intensive and complex
Solution Approach 1:
The invention extracts the complex bolt connection system and replaces it with a simplified spring-based centering mechanism. The guide vane ring is directly centered on the bearing housing without requiring intermediate support rings or multiple bolts, reducing assembly steps while maintaining secure fixation through the elastic force of disc springs
Solution Approach 2:
The conical contact surfaces enable self-centering of the guide vane ring through the elastic force of the disc springs. The system automatically centers itself during assembly without requiring precise manual alignment or complex fastening procedures, making the assembly process more straightforward while ensuring reliable fixation
2Ease of manufacture
If the guide vane ring is pressed against the turbine casing by means of a disc spring, then the centering is simplified, but self-locking and thermal expansion issues arise
Solution Approach 1:
The invention uses conical contact surfaces instead of flat surfaces to prevent self-locking. The inclined conical geometry allows the contact surfaces to slide relative to each other under thermal expansion and load variations, preventing the binding effect that occurs with flat surfaces while maintaining the simplified spring-based centering approach
Solution Approach 2:
The conical contact surfaces change the geometric parameters of the interface between the guide vane ring and bearing housing. The specific cone angle is designed to compensate for thermal expansion effects, maintaining proper clearance and preventing self-locking across the operating temperature range while preserving the ease of assembly provided by the disc spring mechanism
3Device complexity
If the guide vane ring is centered immediately on the bearing housing, then the assembly is simplified, but sealing and centering precision are compromised
Solution Approach 1:
The conical contact surfaces provide both simplified assembly and precise centering. The converging geometry of the cones naturally guides the guide vane ring into accurate concentric alignment with the bearing housing during the spring-based centering process, achieving both assembly simplicity and manufacturing precision simultaneously
Solution Approach 2:
The invention removes intermediate centering components and directly centers the guide vane ring on the bearing housing using conical surfaces. This extraction of unnecessary components simplifies the assembly while the precise conical geometry ensures accurate centering and sealing without compromising precision
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 solution simplifies the assembly process, maintains consistent preload despite thermal expansions, and prevents self-locking, enhancing the operational efficiency and reliability of the exhaust gas turbocharger.
Implementation Method 1
A guide vane ring is non-rotatably arranged which comprises variable guide vanes... The guide vane ring is centered relative to the turbine casing by a matched pair of two contact surfaces pressed against each other, of which at least the one of the contact surface is configured conically. This conical contact surface ensures that the other contact surface automatically assumes the correctly centered position due to the force which presses the two contact surfaces against each other.
Implementation Method 2
If the two contact surfaces are conically formed, it may be provided in a particularly advantageous manner that their matched materials and their cone angles relative to the axis of rotation ensure that no self-locking occurs at the conical centering in the direction of the axis of rotation.
Implementation Method 3
the size of the cone angle ensures that the reduction of a preload of the spring due to thermal expansions of the components of the exhaust gas turbocharger is compensated during its operation
Data Source
AI summary
An exhaust gas turbocharger includes a turbine casing (4) within which a turbine wheel (10) is rotatably arranged relative to an axis of rotation (1). A guide vane ring (22) is non-rotatably arranged which comprises variable guide vanes (44) which are arranged upstream of the turbine wheel (10) with respect to an exhaust gas flow. The guide vane ring (22) is centered by means of a matched pair of two contact surfaces (24, 26) pressed against each other with respect to the turbine casing (4), of which at least the one contact surface (24 or 26, respectively) is formed conically.