Offset-Axis Shaft Coupling With Rolling Pins for Low Friction
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Solution Overview
Problem
Existing couplings that transmit torque between offset axes of rotation often suffer from inefficiencies and reduced stiffness due to sliding friction, leading to energy losses and increased costs from the use of roller bearings.
Innovation Solution
A coupling design featuring pins or rollers that engage in substantially pure rolling motion within holes and rods, eliminating the need for additional bearings and reducing friction, thereby enhancing efficiency and load capacity while maintaining high stiffness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If traditional sliding friction couplings are used to transmit torque between offset axes, then the structure is simple, but efficiency is reduced and energy losses increase
Solution Approach 1:
The patent employs curved, arc-shaped contact surfaces on the coupling elements instead of flat sliding surfaces. The cylindrical pins engage with curved slots in the coupling members, creating rolling contact geometry that reduces friction and improves torque transmission efficiency between offset axes.
Solution Approach 2:
The invention replaces traditional sliding friction-based torque transmission with a rolling contact mechanism. Cylindrical pins rolling within curved slots substitute for direct sliding contact, eliminating the need for roller bearings while achieving higher efficiency through reduced friction losses.
2Loss of energy
If roller bearings are added to reduce friction, then efficiency improves, but cost and device complexity increase
Solution Approach 1:
The patent extracts and eliminates the roller bearing component from the coupling system. By designing cylindrical pins that engage directly with curved slots in the coupling members, the invention removes the need for separate roller bearings while maintaining low friction through rolling contact geometry.
Solution Approach 2:
The coupling elements are designed with self-contained rolling contact geometry where the curved slots and cylindrical pins create inherent rolling motion. This self-service mechanism eliminates the need for external roller bearings, reducing both cost and device complexity while maintaining efficiency.
3Strength
If pins engage in sliding motion, then the coupling structure is simple, but stiffness is reduced and load capacity decreases
Solution Approach 1:
The curved, arc-shaped slots in the coupling members work with cylindrical pins to create rolling contact geometry. This curvature allows the pins to engage multiple teeth simultaneously through rolling motion, increasing stiffness and load capacity compared to simple sliding pin mechanisms.
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 coupling achieves high efficiency and high load capacity with reduced friction losses and cost, providing improved torque transmission characteristics compared to traditional designs.
Implementation Method 1
pins or rollers that engage in substantially pure rolling motion within holes and rods
Implementation Method 2
eliminating the need for additional bearings and reducing friction
Data Source
AI summary
A variety of mechanisms are provided for coupling the rotation of shafts or other mechanical elements having parallel but offset axes of rotation. The coupling mechanisms can couple such input and output elements via pins that are in contact with the input and output elements. The pins, upon rotation of the input and output elements, can engage in substantially pure roiling motion with respect to respective contact surfaces on the input and output members. Accordingly, the pins can reduce the number of bearings and increase efficiency relative to alternative coupling mechanisms. Such couplings may be employed in a variety of applications, including the coupling of rotations between elements of a cycloidal drive or a transmission that includes a member that undergoes cycloidal motion. For example, this coupling could replace the cage gear of a cycloidal drive in coupling the output to the cycloidal disc of a cycloidal drive.