Wave-Shaped Disk Spring for Turbocharger VTG Heat Resistance
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Solution Overview
Problem
Conventional disk springs in variable turbine geometries of exhaust gas turbochargers undergo plastic deformation due to high operating temperatures and have limited installation space, resulting in high stiffness and short spring deflection.
Innovation Solution
A wave-shaped disk spring with large radii of curvature, featuring a profile with one intermediate maximum and two minima, is designed to minimize relaxation effects while maintaining stiffness, achieved through a sheet metal configuration with offset profile sections and continuous transitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If conventional disk springs are used with high tension level, then pre-tensioning function is achieved, but plastic deformation occurs due to high operating temperatures
Solution Approach 1:
The disk spring features a wave-shaped contour with large radii of curvature instead of sharp corners. This curvature distribution prevents stress concentration and reduces the formation of relaxation zones where plastic deformation would occur, allowing the spring to maintain its pre-tensioning function without undergoing plastic deformation at high temperatures
Solution Approach 2:
The invention modifies the geometric parameters of the disk spring by introducing a wave-shaped profile with specific radii of curvature. This changes the stress distribution pattern throughout the spring, shifting from concentrated stress at corners to distributed stress along curved surfaces, thereby preventing plastic deformation while maintaining operational tension
2Volume of moving object
If installation space is limited, then compact design is achieved, but spring deflection becomes short and stiffness increases excessively
Solution Approach 1:
The wave-shaped contour introduces additional geometric complexity in the radial and axial dimensions, allowing the spring to achieve greater effective deflection through the wave profile's vertical undulations rather than requiring increased overall spring height. This enables adequate spring deflection within limited installation space
3Reliability
If wave-shaped contour with large radii of curvature is implemented, then elastically deformable region is enlarged, but manufacturing complexity increases
Solution Approach 1:
The wave-shaped contour is defined by specific geometric parameters including radius values and axial offsets that can be directly programmed into forming tools. By establishing precise parameter relationships (such as the offset distance between radially inner and outer end points), the complex shape becomes manufacturable through controlled forming processes
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 wave-shaped design enhances the elastically deformable region, preventing plastic deformation and maintaining high stiffness, thus addressing the issues of relaxation and space constraints in conventional disk springs.
Implementation Method 1
the elastically deformable region of the disk spring is enlarged compared with conventional disk springs. Undesired operation-induced relaxation effects in the disk spring can be minimized in this way or even completely prevented
Data Source
AI summary
A disk spring may include an annular base body, a central longitudinal axis of which defines an axial direction of the base body. A profile of the base body in a profile plane containing the central longitudinal axis may have a wave-shaped contour with two minima including a radially inner minimum and a radially outer minimum and with an intermediate maximum disposed between the two minima. The wave-shaped contour may extend from a radially inner end point to a radially outer end point. The radially inner end point may be arranged offset in the axial direction with respect to the radially outer end point.