Eccentric Oscillating Gear Reducing Vibration via Friction
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Solution Overview
Problem
Eccentric oscillating reduction gear devices with two rotors experience vibration and noise due to rotational moments and friction, leading to potential downsizing and cost challenges when trying to reduce the number of components.
Innovation Solution
An eccentric oscillating reduction gear device configuration with a first rotor, a second rotor accommodated within the first, and a third rotor that varies the relative rotational phase and includes a fitting portion with a higher friction coefficient than ferrous materials to reduce rotational moments and friction between the second and third rotors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If two rotors are used in the eccentric oscillating reduction gear device, then the device can be downsized and manufacturing cost reduced, but vibration and noise occur due to rotational moments and friction between rotors
Solution Approach 1:
The patent changes the friction coefficient parameter by using resin materials instead of ferrous materials for the rotor surfaces. This parameter change increases friction to prevent rotational moment-induced shifting, thereby reducing vibration and noise while maintaining the two-rotor simple configuration
Solution Approach 2:
The patent employs composite material strategy by combining resin materials with specific surface treatments. The resin material provides high friction coefficient properties, while surface roughness treatment enhances the friction effect, creating a composite solution that addresses vibration and noise without increasing device complexity
2Object-generated harmful factors
If three rotors are used to restrict vibration and noise, then vibration and noise are reduced, but the entire structure is enlarged and manufacturing cost increases
Solution Approach 1:
Instead of adding a third rotor, the patent changes the friction coefficient parameter of the existing two-rotor system by using resin materials. This parameter change achieves vibration and noise reduction without increasing the number of rotors, thereby avoiding structural enlargement and increased manufacturing cost
Solution Approach 2:
The patent extracts the harmful rotational moment effect by increasing friction at the contact surface. By taking out the problematic relative shifting between rotors through high-friction resin materials, the system achieves vibration reduction without needing the third rotor, thus simplifying the overall structure
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 configuration effectively reduces vibration and noise while enabling downsizing and cost reduction by maintaining the second and third rotors in parallel, with increased engagement friction coefficient through resin materials and surface roughness, maintaining smooth operation without the need for additional components.
Implementation Method 1
When friction arises between the inner surface of the second rotor and the outer surface of the fitting portion, a frictional force acts in a direction to reduce a rotational moment, which acts on the third rotor
Data Source
AI summary
A second rotor and a third rotor are accommodated in a first rotor. A fitting portion of the third rotor is located in an engagement hole of the second rotor to engage the third rotor with the second rotor. The third rotor is rotational about an axis, which is eccentric to an axis of the first rotor, to vary a relative rotational phase of the first rotor to the second rotor and to accelerate and decelerate rotation of the second rotor. When friction arises between the second rotor and the fitting portion, a frictional force acts in a direction to reduce a rotational moment acting on the third rotor. A friction coefficient between the second rotor and the fitting portion is greater than a friction coefficient between ferrous objects.