Drive Unit Cable Groove Design for Sliding Door
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Solution Overview
Problem
Existing drive units for sliding doors in vehicles face issues with cable derailing due to narrow spacing between spiral grooves on the drum, leading to cable slipping out when transitioning from a large diameter portion to a small diameter portion during operation.
Innovation Solution
Incorporating a slip preventing wall in the small diameter portion of the drum with a height greater than the cable diameter and increased spacing between adjacent cable grooves, along with a covering wall to prevent cable derailing, ensures reliable cable retention across different drum diameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the spacing between spiral grooves is reduced to increase winding speed, then the winding speed increases, but the cable may slip out of the grooves
Solution Approach 1:
The groove depth is varied locally along the axial direction of the drum. Grooves in the large diameter portion have a first depth, while grooves in the small diameter portion have a second depth that is greater than the first depth. This local variation in groove depth provides enhanced cable retention in the small diameter portion where cables are more prone to slipping, while maintaining adequate winding speed across the entire drum surface.
2Weight of stationary object
If the drum diameter is reduced to decrease moment of inertia, then the moment of inertia decreases, but the cable may derail more easily
Solution Approach 1:
The drum is designed with a tapered structure where the small diameter portion has a greater groove depth compared to the large diameter portion. This local differentiation in groove geometry compensates for the reduced structural containment in the smaller diameter region, preventing cable derailment while maintaining the lower moment of inertia benefits of the tapered drum design.
3Reliability
If the groove depth is increased to prevent cable slippage, then the cable retention improves, but the device complexity increases
Solution Approach 1:
The groove depth parameter is changed along the axial direction of the drum, creating a tapered groove structure. The groove depth increases from the large diameter portion to the small diameter portion. This continuous parameter change provides enhanced cable retention where needed without requiring additional components or complex mechanisms, maintaining manufacturing simplicity while improving reliability.
Data Source
AI summary
A large diameter portion is provided on one side of a closing side drum in an axial direction, a small diameter portion having a diameter gradually decreasing from the large diameter portion to the other side of the closing side drum is provided on the other side of the closing side drum, a partition wall disposed between adjacent small diameter cable grooves in the axial direction of the closing side drum to prevent a closing side cable from slipping out of the small diameter cable grooves is provided in the small diameter portion. Accordingly, the thick partition wall provided in the small diameter portion can reliably prevent the closing side cable from slipping out (derailing) from the small diameter cable grooves even when a winding position of the closing side cable on the closing side drum is changed and transferred from the large diameter portion to the small diameter portion.