Exhaust Flap Shaft Preloading to Suppress Vibration and Noise
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Solution Overview
Problem
Existing flap devices for controlling exhaust gas flow in motor vehicles experience vibrations and noise due to temperature fluctuations and pressure pulsations, which are not effectively mitigated by existing spring-based solutions.
Innovation Solution
A flap device with a spring mechanism that loads the flap shaft tangentially and/or radially only when the flap is rotated from the open to the closed position, ensuring the flap shaft is tense in its closed position and reducing vibrations and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the flap shaft is spring-loaded in both open and closed positions to prevent vibrations, then vibrations and noise are reduced, but an increased force is required to rotate the valve from open to closed position
Solution Approach 1:
The spring means is designed to apply elastic loading only in specific local positions (closed position and intermediate range) rather than continuously throughout the entire rotation range. This localized application of spring force suppresses vibrations and noise at critical positions while avoiding increased rotational force requirements during the full stroke operation.
Solution Approach 2:
The spring means is configured with variable engagement characteristics throughout the rotation range, being actively engaged in the closed position and intermediate range to provide vibration suppression, while disengaged or less engaged in the open position and first rotation range. This dynamic engagement pattern optimizes both vibration control and rotational ease.
2Reliability
If a relatively large bearing clearance is used to prevent jamming due to thermal expansion, then the valve shaft can move freely at high temperatures, but vibrations occur in cold conditions due to excessive play
Solution Approach 1:
The spring means introduces a variable elastic loading parameter that changes with temperature and position. In cold conditions, the spring provides sufficient preloading to reduce bearing play and suppress vibrations. In hot conditions, the spring accommodates thermal expansion through elastic deformation, maintaining reliable operation without jamming while the bearing clearance remains relatively large.
3Object-affected harmful factors
If the spring means loads the flap shaft in the open position to prevent vibrations, then vibrations are suppressed, but the flap shaft cannot rotate smoothly from the open position
Solution Approach 1:
The spring means applies periodic or intermittent loading rather than continuous loading throughout the rotation cycle. The spring is designed to engage and provide vibration suppression only in specific phases (closed position and intermediate range), while allowing free, smooth rotation during other phases (open position and first rotation range). This periodic action pattern eliminates vibrations when needed while preserving ease of operation when the spring is disengaged.
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 effectively suppresses vibrations and noise associated with the flap device, particularly in the closed position, while allowing for smooth rotation and maintaining the flap's tension both in warm and cold states.
Implementation Method 1
a spring means (18) which, when the flap (10) is rotated from the open position into the closed position, at the latest in the closed position of the flap (10), elastically loads the flap shaft (14)
Implementation Method 2
the spring force of the spring means (18) acts in a tangential and/or radial direction with respect to the axis of rotation of the flap shaft (14), in particular towards the axis of rotation
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The invention relates to a flap device for controlling a gas flow through a pipeline, in particular an exhaust flap device for an exhaust system of a motor vehicle, with at least one flap which is rotatably arranged in a flap housing, in particular a tubular one, about an axis of rotation of a flap shaft between an open position and a closed position, in particular by means of a drive unit, wherein a spring element is provided which, when the flap is rotated from the open position to the closed position, at the latest in the closed position of the flap, elastically loads the flap shaft tangentially and/or radially, wherein the spring element is directly or indirectly connected to the flap housing in a rotationally fixed manner with respect to a rotation about the axis of rotation by at least one section.