Roller Coating for CVVT Speed Reducer Noise
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Solution Overview
Problem
Existing electric CVVT speed reduction devices generate excessive noise due to backlash between rollers and cage or rollers and inner tooth, caused by torque changes in the camshaft, leading to impact noise.
Innovation Solution
A noise reducing coating layer is applied to the exterior circumference of rollers, the inner surface of the pocket, and the roller contact surface of the inner tooth, composed of a polyamideimide resin with dispersed aerogel, which absorbs and eases the impact from collisions, reducing noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a speed reduction device with rollers and cage is used to transmit rotation from electric motor to camshaft, then the valve timing control precision is improved, but excessive noise is generated due to backlash between rollers and cage or between rollers and inner tooth
Solution Approach 1:
A coating layer is applied to the surface of rollers and/or inner tooth to serve as an intermediary material that absorbs impact energy during collisions caused by backlash, thereby reducing noise while preserving the mechanical transmission function
Solution Approach 2:
The surface properties of rollers and/or inner tooth are modified by applying a coating layer with different physical properties (softer, more compliant), changing the impact characteristics from hard collision to cushioned contact, thus reducing noise
2Object-generated harmful factors
If a coating layer is applied to reduce impact noise, then the noise level is reduced, but the device complexity increases
Solution Approach 1:
The coating layer is applied locally only to specific surfaces (rollers and/or inner tooth) where impact occurs, rather than throughout the entire device, thereby reducing noise with minimal increase in overall device complexity
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 coating layer effectively absorbs and reduces impact noise by minimizing the impact from collisions between rollers and the cage or inner tooth, enhancing mechanical properties and durability while maintaining the physical properties of the aerogel.
Implementation Method 1
a coating layer that eases impact is formed in exterior circumference portions of the rollers... a coating layer that eases impact is formed in an inner surface of the pocket and a roller contact surface of the inner tooth
Data Source
AI summary
A noise reducing apparatus of a speed reduction device for electric continuous variable valve timing (CVVT), may include the speed reduction device having an inner tooth portion formed to be faced opposing an external wheel of a ball bearing in an interior diameter surface of a housing that may be integrally formed with a sprocket and rollers arranged through a cage between an inner tooth of the inner tooth portion and the external wheel of the ball bearing, wherein a coating layer may be formed to ease impact in exterior circumference portions of the rollers.