Flexible Pipe Assembly Bellows Vibration Absorption
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Solution Overview
Problem
Existing exhaust pipe systems in vehicles face challenges in withstanding vibrational stresses due to resonance frequencies, leading to potential failure at points of connection between the exhaust aftertreatment system and the vehicle chassis or cab, as they struggle to balance stiffness and flexibility to absorb relative movements between these components.
Innovation Solution
A flexible pipe assembly featuring a pipe within a sleeve with connection assemblies that constrain radial, axial, and torsional degrees of freedom, incorporating a bellows to allow bending and deformation, thereby increasing resistance to failure from vibrational stresses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the exhaust pipe is rigidly connected to the EAS outlet to improve resistance against vibrational stresses, then the connection strength is improved, but the ability to accommodate relative movement between chassis and cab deteriorates
Solution Approach 1:
The patent employs a flexible exhaust pipe with integrated bellows sections that can expand and contract to accommodate relative movement between the chassis-mounted EAS and the cab-mounted exhaust outlet. The flexible pipe material and bellows structure allow the connection to maintain structural integrity while adapting to vibrational movements and position changes, thus resolving the contradiction between connection strength and adaptability.
Solution Approach 2:
The exhaust pipe system is designed with dynamic characteristics that allow it to respond to vibrational stresses and relative movements. The pipe's flexibility and the bellows' expansion/contraction capability enable the system to dynamically adjust to changing conditions during vehicle operation, maintaining both strength and adaptability simultaneously.
2Adaptability or versatility
If the exhaust pipe is mounted too loosely to allow relative movement, then the adaptability is improved, but the harmfulness of stresses and movements increases due to excessive movement or resonance
Solution Approach 1:
The flexible pipe with controlled flexibility provides a balanced solution that allows necessary relative movement while maintaining sufficient structural rigidity to prevent excessive movement and resonance. The bellows structure provides flexibility for movement accommodation while the overall pipe design maintains structural integrity to filter out harmful vibrations.
Solution Approach 2:
The patent optimizes the physical parameters of the exhaust pipe, including its flexibility modulus, wall thickness, and bellows geometry, to achieve the right balance between allowing relative movement and preventing excessive movement. By carefully controlling these parameters, the system accommodates necessary movements while filtering out harmful vibrations and resonances.
3Adaptability or versatility
If the exhaust pipe is provided with bends to couple to the EAS outlet, then the adaptability to different positions is improved, but the likelihood of failure at bend points increases due to stress concentration
Solution Approach 1:
The flexible pipe design eliminates rigid bends and sharp corners that create stress concentration points. Instead, the pipe uses gradual curves and flexible bellows sections that can accommodate position changes without creating localized stress peaks, thereby maintaining both adaptability and reliability.
Solution Approach 2:
The flexible pipe with bellows provides a dynamic solution that allows the exhaust system to adapt to different positions through controlled flexing rather than rigid geometric changes. This dynamic adaptation reduces stress concentration at connection points while maintaining coupling adaptability.
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 flexible pipe assembly enhances the lifespan of the exhaust system by absorbing vibrational forces and relative movements, maintaining high stiffness in necessary degrees of freedom to prevent resonance and modal vibrations, while allowing flexibility to reduce stress and strain.
Implementation Method 1
The pipe may include a first end portion, a second end portion, and a bellows between the first end portion and the second end portion. The bellows may allow flexing, bending, and deformation in the pipe between the first end portion and the second end portion to increase resistance against failure in the exhaust pipe system due to relative movement between a chassis and a cab of the truck when in use.
Data Source
Figure 1A
Figure 1B~1C
Figure 1D
AI summary
The present disclosure is directed to a flexible pipe assembly (100) that includes a pipe (102), a sleeve (104), a first connection assembly (106), and a second connection assembly (108). The pipe of the flexible pipe assembly includes a first end portion (130) that is coupled to an external vertical exhaust pipe that allows exhaust to escape from a truck and a second end portion (132) that is coupled to a pipe to an outlet of an exhaust aftertreatment system (EAS). The pipe also includes a third portion (134), which is a bellows, coupling the first end portion (130) to the second end portion (132) of the pipe of the flexible pipe assembly. The first and second connection assemblies couple the sleeve to the pipe of the flexible pipe assembly by passing through holes (144, 146, 148, 150) in the sleeve and the pipe (136, 138, 140, 142) of the flexible pipe assembly.