Semi-Trailer Support Device Spindle Bending Stress Reduction
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Solution Overview
Problem
Existing support devices for semi-trailers experience bending stress and material inefficiencies due to rigid spindle connections, leading to potential unusability under load conditions.
Innovation Solution
A support device with a rotatable spindle and a spindle nut fixed to a supporting edge on the inner tube, allowing for relative movement between inner and outer tubes, and featuring a curved bearing surface to distribute loads and reduce bending stress, along with a support flange for load transfer and radially protruding hooking areas for secure fixation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the spindle nut is rigidly connected to the inner tube of the support, then the vertical load is effectively absorbed, but the bending stress on the spindle increases significantly under lateral forces
Solution Approach 1:
The connection between the spindle nut and inner tube is segmented into two independent functions: the spindle nut remains stationary relative to the outer tube to absorb vertical loads, while the inner tube can move independently to accommodate lateral forces. This segmentation prevents the transmission of bending moments from the inner tube to the spindle.
Solution Approach 2:
The supporting edge on the inner tube acts as an intermediary element between the spindle nut and the inner tube body. It provides a localized bearing surface that allows the spindle nut to be fixed to the inner tube without rigidly connecting the entire inner tube structure to the spindle, thereby reducing bending stress.
2Stability of the object's composition
If the inner tube and outer tube are rigidly connected, then structural stability is improved, but the device complexity and material requirements increase
Solution Approach 1:
The connection between the inner tube and outer tube transitions from a rigid static connection to a dynamic arrangement where the inner tube can move independently within the outer tube. The spindle nut remains stationary relative to the outer tube while the inner tube can shift position, providing adaptability without requiring complex rigid connection structures.
3Reliability
If the spindle nut has greater lateral movement play than the inner tube, then spindle bending is avoided, but the manufacturing precision requirements increase
Solution Approach 1:
The supporting edge provides a localized bearing surface with precise geometry that controls lateral movement play. Instead of requiring the entire spindle nut assembly to have controlled play, only the local contact area at the supporting edge needs precise manufacturing, reducing overall manufacturing precision requirements while still protecting the spindle.
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 reduces bending stress on the spindle, requires less material, simplifies assembly and disassembly, and enhances the support device's durability and usability under load conditions.
Implementation Method 1
featuring a curved bearing surface to distribute loads and reduce bending stress
Data Source
Figure 1~2
Figure 3~4
AI summary
Support device, preferably for commercial vehicles such as semi-trailers, comprising an inner support tube and an outer support tube, which can be displaced relative to one another along a longitudinal axis in an extension and retraction direction; a spindle that can be rotated via a gear section and is arranged such that it is stationary relative to the outer support tube; and a spindle nut which is mounted on the spindle, wherein the spindle nut is fixed on a mounting region of the inner support tube, said mounting region being formed as a support edge facing the longitudinal axis.