Integral Tripod Drive Shaft for Simpler Torque Transmission
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Solution Overview
Problem
Manufacturing drive shafts with tripod joints for motor vehicles is complex due to the need for separate production of the tripod joint and splined connection, which complicates assembly and increases manufacturing effort.
Innovation Solution
A drive shaft with a tripod coupling formed by a formed section of the shaft body, eliminating the need for separate manufacturing and assembly, and utilizing a forged steel alloy with a one-piece design to enhance torque transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the tripod joint is produced using a forming process and fitted with splined teeth separately, then the tripod joint can be manufactured, but the manufacturing complexity increases and assembly becomes more difficult
Solution Approach 1:
The patent merges the tripod joint and the shaft into a single integrated component. The tripod joint is formed directly from the shaft body through a forming process, eliminating the need for separate manufacturing and assembly of the tripod joint and shaft. This integration resolves the technical contradiction by simplifying both manufacturing and assembly processes while maintaining the functional requirements of the drive shaft system
2Strength
If a positive-locking connection between shaft and tripod coupling is used, then torque transmission is achieved, but the torque transmission capability is limited compared to integral design
Solution Approach 1:
The integral design merges the shaft and tripod joint into one continuous component, eliminating the positive-locking connection interface. This allows for more effective torque transmission as there is no discontinuity or potential failure point at a connection interface, while simultaneously reducing device complexity by removing the need for separate coupling components and their associated fastening mechanisms
3Weight of moving object
If the shaft body is made hollow to reduce weight, then weight is reduced, but the torsional stiffness may be compromised
Solution Approach 1:
The patent applies local quality by varying the wall thickness of the hollow shaft body. The shaft has different wall thicknesses in different sections, with thicker walls in regions requiring higher strength and stiffness, and thinner walls where weight reduction is prioritized. This allows the hollow shaft to maintain adequate torsional stiffness while achieving weight reduction, resolving the technical contradiction between these two parameters
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 allows for cost-effective, efficient manufacturing of a drive shaft with improved torque transmission capabilities and reduced weight, while maintaining high strength and mechanical properties.
Implementation Method 1
the tripod coupling is formed by upsetting the shaft
Implementation Method 2
this material enables area-specific hardening
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention relates to a drive shaft for the drive train of a motor vehicle, comprising a shaft body (11) provided at at least one end with a tripod star having three tripod pins (22) for each receiving a roller unit, wherein the tripod star is formed by a formed section of the shaft body (11). The shaft body (11) is in particular tubular in shape. According to a method for manufacturing a hollow drive shaft, a tripod star is formed at at least one end of a metal tube by forming, the tripod star having three circumferentially arranged tripod pins (22), after which the tripod star is machined.