Rotary Joint Wiring Unit Roller Slide Aid
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Solution Overview
Problem
Existing rotary joint wiring units for industrial robots face issues with early wear and tear of flexible printed wiring boards due to high-speed and long-duration rotation, leading to reduced lifespan and potential disconnection.
Innovation Solution
A rotary joint wiring unit design featuring a cylindrical housing with a reel and a slide aid, including rollers and a protective pole, which allows the flexible printed wiring board to wind and unwind, reducing friction and wear by using rollers with larger diameters and protective structures to prevent entanglement and buckling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a cable is wired through the center of rotation of a rotary joint to absorb relative rotation by twisting the cable, then the wiring structure allows rotation between two members, but the high rate of twisting per unit length hastens damage or disconnection of the cable
Solution Approach 1:
The cable is divided into multiple strands that can twist independently relative to each other. This segmentation allows the cable to accommodate rotation through distributed twisting of individual strands rather than forcing the entire cable to twist as a single unit, reducing stress concentration and preventing damage.
Solution Approach 2:
The cable structure incorporates radial expansion capability, allowing strands to move not only axially but also radially outward during rotation. This dimensional change provides additional space for strand movement, reducing twisting stress and preventing cable damage while maintaining rotation capability.
2Reliability
If the portion corresponding to the center of rotation of a rotary joint is elongated to reduce twisting rate, then cable damage is reduced, but the space required for wiring increases and the size of the rotary joint increases
Solution Approach 1:
By segmenting the cable into multiple movable strands, the effective twisting length is increased without increasing the overall rotary joint dimensions. Each strand can twist independently within the compact space, maintaining cable durability while avoiding size increase.
Solution Approach 2:
The cable employs a flexible stranded construction with thin insulation layers that allows significant twisting and bending within a compact volume. This flexible structure enables the cable to accommodate rotation stresses without requiring excessive space, maintaining both durability and compactness.
3Ease of operation
If a flexible sheet is flexed and extended with relative rotation between two members, then rotation is absorbed, but force concentration in certain areas accelerates fatigue and breakage
Solution Approach 1:
The flexible sheet is segmented into multiple parallel conductors or strands that can deform independently. This segmentation distributes the mechanical stress and force concentration across multiple elements rather than concentrating it in a single sheet, reducing fatigue accumulation and extending lifespan while maintaining rotation absorption capability.
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 design effectively extends the lifespan of the wiring unit by minimizing wear and preventing entanglement, allowing for continuous high-speed operation without premature damage to the flexible printed wiring board.
Implementation Method 1
a plurality of rollers provided on the rotary plate to be located around the core member and rotatable about an axis of each roller
Data Source
AI summary
A wiring unit is provided for robots having a rotary joint. This unit includes a wiring case, a slide aid contained in the wiring case, and a flexible printed wiring board for electric wiring. The wiring case includes a cylindrical housing and a reel with a cylindrical core member. The reel is relatively rotatable to the housing. The reel and housing are linked with robot's two members requiring the rotary joint. In the slide aid, an annular rotary plate surrounds the core member and is rotatable about the core member. Plural rollers are provided on the rotary plate and self-rotatable. The wiring board has electrical wires and is connected to the core member and housing and is wound and unwound in radially inside and outside spaces of the rollers via the vacant space by moving on and along the rollers.