Shaft-Hub Connection With Variable Excess Press-Fit
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Solution Overview
Problem
Conventional shaft-to-hub connections in drive trains face challenges in achieving cost-effective and time-effective assembly while maintaining resistance to high rotating speeds, thermal resistance, and torque transmission, often resulting in potential damage during the joining process due to high joining forces and contact pressures.
Innovation Solution
A shaft-to-hub connection with a longitudinal press-fit featuring variable excess regions, allowing for a rotationally-fixed connection with a large contact face, which reduces the risk of damage during assembly and enhances cooling and torque transmission, by incorporating different excess values and angles in the circumferential direction of the shaft element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional longitudinal press-fit with uniform excess is used to connect the shaft element to the hub element, then a rotationally-fixed connection is achieved, but the joining process causes damage due to high joining forces and contact pressures
Solution Approach 1:
The patent applies local quality by varying the excess distribution along the longitudinal press-fit interface. Different regions of the press-fit have different excess values, allowing optimization of joining forces in different zones. This reduces peak contact pressures that cause damage while maintaining sufficient connection stability in critical regions.
Solution Approach 2:
The patent changes the geometric parameter of the excess distribution from uniform to variable. By adjusting the excess value at different positions along the press-fit length, the joining characteristics are optimized to reduce harmful contact pressures while maintaining connection reliability.
2Reliability
If a longitudinal press-fit with large excess is used to ensure rotationally-fixed connection, then connection stability is improved, but assembly cost and time increase
Solution Approach 1:
The variable excess distribution allows critical regions requiring high connection stability to have larger excess values, while non-critical regions have reduced excess. This maintains overall connection reliability while reducing the total material removal and assembly complexity, improving productivity.
3Ease of manufacture
If a longitudinal press-fit with uniform excess is used, then manufacturing is simplified, but thermal resistance and torque transmission are insufficient
Solution Approach 1:
The patent optimizes excess distribution to create regions with enhanced contact pressure that improve thermal conduction paths and torque transmission capability. While manufacturing complexity increases slightly, the localized optimization provides superior thermal and mechanical performance compared to uniform excess designs.
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 enables a cost-effective, stable, and efficient assembly that withstands high rotating speeds without hub lifting, while providing improved thermal resistance and torque transmission, with reduced energy input and production costs compared to traditional methods.
Implementation Method 1
The shaft element by way of a longitudinal press-fit that includes the longitudinal regions is connected to the hub part at least in a rotationally-fixed manner. This means that at least one press-fit is formed between the longitudinal regions and thus between the shaft element and between the hub element
Implementation Method 2
The longitudinal press-fit has at least one first excess region having a first excess and, so as to follow the first excess region in the circumferential direction of the shaft element, at least one second excess region having a second excess that is smaller in relation to the first excess
Data Source
AI summary
A shaft-hub connection including a hub element and a shaft element is provided. The hub element includes a hub. The shaft element includes at least one first elongated region arranged in at least one second elongated region of the hub and is at least rotationally fixed to the hub element by way of a longitudinal press-fit including the elongated regions. The longitudinal press-fit has at least one first excess region with a first excess, and at least one second excess region, following the first excess region in the circumferential direction of the shaft element, with a second excess that is smaller than the first excess.