Steering Shaft Assembly With Redundant Rotary Torque Coupling
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Solution Overview
Problem
Existing steering shaft assemblies for motor vehicles lack robustness in torque transmission during defects, particularly in the coupling area, which can lead to reduced steerability and increased effort in axial adjustments.
Innovation Solution
A redundant torque transmission coupling system with two rotary coupling mechanisms of differing play, where one mechanism with rolling elements provides reliable torque transmission and easy axial adjustment, while the other mechanism with greater play ensures continued steerability in case of defects, using rolling bodies and coupling projections for secure and easy mounting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single rotary coupling mechanism is used to couple the first shaft and second shaft, then the device complexity is reduced, but the reliability of torque transmission deteriorates in case of defect
Solution Approach 1:
The coupling mechanism is segmented into two independent rotary coupling mechanisms (first and second mechanisms) that operate in parallel. Each mechanism can independently transmit torque, so if one fails, the other continues to function, ensuring reliable torque transmission while maintaining relatively simple individual mechanism designs
Solution Approach 2:
The redundant second rotary coupling mechanism serves as a pre-prepared backup system. In normal operation, the first mechanism handles torque transmission, while the second mechanism stands ready to take over if the first mechanism fails, providing beforehand cushioning against potential defects
2Manufacturing precision
If a rotary coupling mechanism with small play is used, then the torque transmission precision is improved, but the ease of axial adjustment deteriorates
Solution Approach 1:
The axial adjustment function is segmented from the torque transmission function. The first rotary coupling mechanism with small play handles precise torque transmission, while the second mechanism with greater play handles axial adjustment, allowing both functions to optimize for their respective purposes without compromise
Solution Approach 2:
The second rotary coupling mechanism with greater play acts as an intermediary that facilitates easy axial adjustment between the first and second shafts. Its larger play allows smooth axial movement with minimal resistance, while the first mechanism maintains precise torque transmission during rotation
3Ease of operation
If a rotary coupling mechanism with greater play is used, then the ease of axial adjustment is improved, but the torque transmission precision deteriorates
Solution Approach 1:
The system segments the functions of axial adjustment and torque transmission into two separate rotary coupling mechanisms. The second mechanism with greater play is dedicated to axial adjustment, while the first mechanism with small play handles precise torque transmission, eliminating the need to compromise precision for adjustment ease
Solution Approach 2:
The system dynamically switches between the two rotary coupling mechanisms based on operational needs. During axial adjustment, the second mechanism with greater play is engaged to reduce resistance, while during torque transmission, the first mechanism with small play provides precise coupling
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 ensures the motor vehicle remains steerable even with defects, allows easy axial adjustment with minimal effort, and maintains a simple and cost-effective manufacturing process by utilizing rolling bodies and coupling projections for reliable torque transmission and easy assembly.
Implementation Method 1
The first shaft and the second shaft are coupled in a torque-conducting manner via a first rotary coupling mechanism and a second rotary coupling mechanism. The first of the two rotary coupling mechanisms has at least one rolling body which is mounted in a form-fitting manner on both the first shaft and the second shaft
Implementation Method 2
The rotary coupling part is reliably connected to the first shaft due to the frictional connection
Data Source
Figure 1~2
Figure 3~4
AI summary
A steering shaft assembly (10) for a motor vehicle is described, comprising a first shaft (20) and a second shaft (22), both of which are rotatable about a central axis (24). The second shaft (22) is a hollow shaft, and a section of the first shaft (20) is axially displaceable within the second shaft (22). The first shaft (20) and the second shaft (22) are also torque-conductingly coupled via two separate rotary coupling mechanisms (26, 28).