Rotary Connector Regulating Walls Guide Flat Cable
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Solution Overview
Problem
Conventional rotary connectors for automobile steering devices with inverted flat cables suffer from structural complexity and noise issues due to the use of rollers, which can lead to rattle and require high-stiffness cables, while simpler designs with planetary gears face challenges in smoothly rotating the movable-side housing with thin, low-stiffness cables.
Innovation Solution
A rotary connector design featuring a moving body with regulating walls and protrusions in the annular space, where the planetary gear meshes with internal and sun gears, and the regulating walls extend circumferentially with openings to guide the flat cable, reducing the need for rollers and simplifying the structure, while the number and arrangement of protrusions optimize sliding friction and rotation smoothness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If rollers are used to regulate flat cable movement in the annular space, then the flat cable can be smoothly fed, but the structure becomes complex and noise increases due to rattle
Solution Approach 1:
The patent removes the rollers from the system and replaces them with a guide wall structure integrated into the moving body. The guide wall directly guides the inverted portion of the flat cable without requiring intermediate rolling elements, thereby simplifying the structure while maintaining smooth cable feeding functionality.
Solution Approach 2:
The guide wall is integrated directly into the moving body structure, combining the functions of structural support and cable guidance into a single component. This eliminates the need for separate roller assemblies and reduces overall device complexity.
2Ease of operation
If rollers are used to regulate flat cable movement, then the flat cable can be smoothly fed, but noise increases due to rattle between rollers and support shafts
Solution Approach 1:
The patent eliminates the rollers and their associated support shafts from the system. By using a guide wall integrated into the moving body, the source of rattle and noise is removed entirely, while the cable guidance function is maintained through the guide wall's geometric configuration.
3Device complexity
If a planetary gear is used to rotate the moving body at the same speed as the inverted portion, then the structure is simplified, but thin low-stiffness flat cables cause rotation issues
Solution Approach 1:
The guide wall acts as an intermediary between the planetary gear mechanism and the flat cable. It provides a constrained path for the inverted portion of the cable, ensuring proper alignment and reducing lateral forces that would otherwise affect thin, low-stiffness cables during rotation.
Solution Approach 2:
The patent optimizes the geometric parameters of the guide wall, including its angle and position, to match the rotational characteristics of the planetary gear. This parameter optimization ensures that the guide wall effectively channels the cable movement during rotation, improving reliability with thin cables.
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
This design simplifies the structure, reduces noise, and allows for smooth rotation of the movable-side housing using thin, low-stiffness flat cables by optimizing the number and arrangement of protrusions and the opening angles, thereby enhancing the connector's operational efficiency and cost-effectiveness.
Implementation Method 1
A planetary gear supported by the moving body meshes with an internal gear provided on the stationary-side housing and a sun gear provided on the movable-side housing
Implementation Method 2
a plurality of protrusions, which protrude toward an inner peripheral surface of the outer cylindrical body, are repeatedly formed on outer peripheral surfaces of the regulating walls at regular intervals in the circumferential direction so that the total number N of the protrusions satisfies '11≦N≦35'
Data Source
AI summary
In a rotary connector where a moving body turning with the rotation and revolution of a planetary gear and a flat cable including an inverted portion at a middle portion thereof are received in an annular space defined between an outer cylindrical body of a stationary-side housing and an inner cylindrical body of a movable-side housing, regulating walls, which extend in a circumferential direction with an opening interposed therebetween, are erected on a moving body formed of a resin molded product and the inverted portion passes through the opening so that the movement of the flat cable in a radial direction is regulated. Further, a plurality of protrusions, which protrude toward the inner peripheral surface of the outer cylindrical body, are repeatedly formed in the circumferential direction on the outer peripheral surfaces of the regulating walls.