Composite Interference-Fit Hub for High-Torque Lightweight Shafts
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Solution Overview
Problem
Conventional interference fit connections for coupling lightweight fiber composite drive shafts to steel shafts in drive trains are heavy and complex, failing to efficiently transmit high drive torques while maintaining low weight.
Innovation Solution
A two-component interference fit connection is developed, where a steel hub is reinforced with a fiber-reinforced plastics ring having a higher modulus of elasticity, which surrounds the sleeve portion, allowing for increased stiffness and reduced weight, along with friction-increasing measures on the conical and cylindrical surfaces to enhance torque transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a conventional solid steel hub is used for interference fit connection, then high torque transmission is achieved, but component weight increases significantly
Solution Approach 1:
The hub is constructed as a composite structure with a steel sleeve providing structural support and a fiber-reinforced plastic outer ring providing stiffness and torque transmission. This composite design reduces weight compared to solid steel while maintaining torque transmission capability through the optimized combination of materials with complementary properties.
Solution Approach 2:
Different regions of the hub have different material properties optimized for their specific functions: the steel sleeve provides structural integrity and interference fit capability, while the fiber-reinforced plastic outer ring provides radial stiffness and torque transmission. This local optimization allows weight reduction without compromising overall performance.
2Weight of moving object
If the hub is made lightweight using fiber composite materials, then weight is reduced, but radial stiffness decreases
Solution Approach 1:
The composite hub structure combines steel and fiber-reinforced plastic materials, where the steel sleeve provides the necessary radial stiffness and structural support, while the fiber-reinforced plastic outer ring contributes to overall stiffness and torque transmission. This combination achieves lightweight construction without sacrificing radial stiffness.
Solution Approach 2:
The steel sleeve is designed with specific dimensional parameters (wall thickness, length) and the fiber-reinforced plastic ring is configured with optimized geometry to ensure that the composite structure achieves the required radial stiffness. By carefully controlling these parameters, the hub maintains sufficient stiffness while minimizing weight.
3Force
If a steel ring is press-fitted on the outer circumference to increase torque transmission, then torque capacity is improved, but outer diameter and overall weight increase
Solution Approach 1:
Instead of adding a separate steel ring that increases outer diameter, the hub uses a composite structure where the fiber-reinforced plastic outer ring is integrally formed with the steel sleeve. This composite design achieves enhanced torque transmission capability without increasing the outer diameter, as the fiber-reinforced plastic material provides high specific strength and stiffness.
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 achieves significant weight reduction and increased radial stiffness, enabling high torque transmission with a compact, lightweight design, facilitating assembly through hydraulic pressing and reducing overall weight compared to conventional steel hubs.
Implementation Method 1
the fiber-reinforced plastics material has a higher modulus of elasticity than the steel of the first component
Implementation Method 2
interference fit connection... conical through opening... conical outer circumference
Data Source
AI summary
An interference fit connection for a shaft comprises a hub having a conical through opening and a reduction sleeve having a cylindrical through opening for arrangement on the shaft and a conical outer circumference, where the cone angle of the conical outer circumference corresponds to the cone angle of the corresponding conical through opening of the hub. The hub is a two-component part having a first component made of steel and a second component made of fiber-reinforced plastics material. The second component made of fiber-reinforced plastics material is designed as a ring which is arranged on the outer circumference of a sleeve portion of the first component, which sleeve portion surrounds the reduction sleeve, so as to surround this sleeve portion. The fiber-reinforced plastics material has a higher modulus of elasticity than the steel of the first component.