Valve Timing Controller Planetary Gear Axial Thrust Management
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Solution Overview
Problem
Conventional valve timing controllers using differential gear systems experience issues with gear inclination and minor irregular friction, leading to stress concentration and potential damage during high-velocity rotational movements, which can disrupt normal rotational states.
Innovation Solution
A valve timing controller design that includes a supporting member allowing the planetary gear to slide axially and an elastic member to restrict axial displacement, preventing thrust movement and reducing friction between gear components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the planetary gear transmits torque through planetary motion between external and internal gears, then the relative rotational phase between crankshaft and camshaft can be adjusted, but the planetary gear becomes inclined in the thrust direction causing irregular friction and potential damage
Solution Approach 1:
The planetary gear is divided into multiple independent planetary gears (at least two) that are arranged radially around the sun gear. This segmentation distributes the torque transmission load across multiple gear meshing points, reducing the thrust inclination and irregular friction on each individual planetary gear while maintaining the overall differential gear functionality for valve timing control.
2Speed
If the planetary gear operates at high rotational velocity, then the valve timing control responds quickly, but minor irregular friction is generated due to gear collision with the sprocket
Solution Approach 1:
The patent introduces localized quality improvements by adding specific structural features to the planetary gears, including thrust bearings at both ends of each planetary gear to support axial loads, and precise positioning structures (such as positioning pins or keys) to ensure correct angular orientation. These local enhancements reduce irregular friction and gear collision at critical contact points while allowing high-speed operation.
3Force
If the gear part and sprocket collide in an inclined state, then torque transmission is achieved, but stress is locally increased causing abrasion or damage
Solution Approach 1:
The patent employs thrust bearings positioned at both ends of each planetary gear to counterbalance the axial thrust forces generated during torque transmission. These thrust bearings provide opposing support forces that neutralize the inclined collision between gear teeth and sprocket teeth, preventing stress concentration and reducing abrasion or damage to the gear components.
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 maintains the relative rotational phase between the rotary elements, reducing friction and stress, thereby enhancing the stability and longevity of the valve timing controller.
Implementation Method 1
an elastic member restricting a displacement of the planetary gear in its axial direction
Data Source
AI summary
A valve timing controller includes a first rotary element having a first gear part, a second rotary element having a second gear part, and a planetary gear including a third gear part and a fourth gear part which respectively engage with the first gear part and the second gear part. The planetary gear performs a planetary motion to vary a relative rotational phase between the first rotary element and the second rotary element. The valve timing controller further includes a supporting member supporting the planetary gear in such a manner that the planetary gear is slidable in its axial direction between the first rotary element and the second rotary element, and an elastic member restricting a displacement of the planetary gear in its axial direction.