Composite Bush Axial Rigidity Tuning for CTBA Suspension
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Solution Overview
Problem
The existing bush systems in vehicle suspension systems face limitations in tuning freedom due to rubber characteristics, which restrict the achievement of optimal Ride and Handling (R&H), Noise, Vibration, Harshness (NVH), steering, and durability, particularly in Coupled Torsion Beam Axle (CTBA) systems, leading to response delays and over-steer tendencies.
Innovation Solution
A bush design that combines the rigidity and shape of the bush with rubber characteristics, enhancing tuning freedom by increasing axial and rotational rigidity while reducing front and rear directional rigidity, achieved through a combination of plastic and rubber modulus of elasticity, with specific protrusions and voids, and a composite structure using engineering plastic and rubber, allowing for adjustable rigidity and elasticity tuning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a bush is designed using only rubber characteristics for elastic tuning, then it can provide vibration damping and flexibility, but the tuning freedom degree is reduced and it is difficult to achieve optimal R&H/NVH/steering/durability performance simultaneously
Solution Approach 1:
The bush combines rubber material with plastic material to create a composite structure that integrates both elastic tuning (via rubber) and rigidity tuning (via plastic). This composite approach enables simultaneous optimization of vibration damping and structural rigidity, achieving improved R&H/NVH/steering/durability performance while increasing tuning freedom degree
Solution Approach 2:
The bush is divided into multiple functional sections: a rubber portion for elastic tuning and vibration damping, and a plastic portion for rigidity tuning and structural support. This segmentation allows independent optimization of each material's properties to achieve overall performance goals
2Stability of the object's composition
If the bush is tilted to provide stability through Toe In induction, then lateral force resistance is improved, but response delay occurs to initial lateral acceleration due to over-steer tendency
Solution Approach 1:
The plastic portion of the bush is designed with adjustable rigidity parameters that can be tuned to optimize the balance between stability and response time. By modifying the plastic modulus of elasticity and geometric parameters of the plastic structure, the bush can provide sufficient lateral force resistance while reducing response delay to initial lateral acceleration
3Strength
If the bush increases rigidity in axial and rotational directions, then steering precision and durability are improved, but front and rear directional rigidity becomes excessive affecting ride comfort
Solution Approach 1:
The bush design applies different rigidity characteristics to different directions and locations. The plastic portion is specifically engineered to provide high rigidity in axial and rotational directions for steering precision and durability, while maintaining appropriate flexibility in front and rear directions for ride comfort. This is achieved through localized geometric features and material distribution in the plastic structure
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 design significantly increases the tuning freedom degree, optimizing R&H, NVH, steering, and durability performance, reduces development load, and allows for cost-effective and weight-efficient manufacturing, while improving handling and stability by adjusting coupling and detaching forces.
Implementation Method 1
an outer pipe forming a third protrusion at a first inner side, and a fourth protrusion at a second inner side. In particular, the third and fourth protrusions are arranged outside of the central protrusion. The bush sets the plastic modulus of elasticity of the second inner pipe as the rigidity tuning, sets the rubber modulus of elasticity of a rubber part provided between the second inner pipe and the outer pipe so as to have a value different from the plastic modulus of elasticity as the elastic tuning
Implementation Method 2
The bush sets the plastic modulus of elasticity of the second inner pipe as the rigidity tuning, sets the rubber modulus of elasticity of a rubber part provided between the second inner pipe and the outer pipe so as to have a value different from the plastic modulus of elasticity
Data Source
AI summary
A bush may include: a second inner pipe forming a central protrusion in a central section of the second inner pipe; and an outer pipe forming a third protrusion at a first inner side and a fourth protrusion at a second inner side. In particular, the third and fourth protrusions are arranged outside of the central protrusion.