Asymmetric Planetary Carrier Support for Valve Timing Adjuster
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Solution Overview
Problem
The existing valve timing adjusting devices for internal combustion engines face durability issues due to the inclination of the planetary rotator, which generates thrust loads between gear sections, leading to reduced durability.
Innovation Solution
A valve timing adjusting device design where the support section of the planetary carrier is positioned on the inner peripheral side of one tooth contact center and separate from the other, ensuring the first moment generated by the radial load is larger than the second moment, thereby inhibiting the inclination of the planetary rotator and preventing thrust loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the planetary carrier supports the planetary rotator on both inner peripheral sides of tooth contact centers, then the planetary rotator is stable, but the device complexity increases and durability decreases due to thrust loads
Solution Approach 1:
The patent removes one support section from the planetary carrier, leaving it to support the planetary rotator at only one location (on the inner peripheral side of the first tooth contact center). This extraction of the unnecessary support section simplifies the support structure while preventing thrust load generation that would occur with dual support, thereby improving durability without excessive complexity
Solution Approach 2:
The patent creates an asymmetric support configuration where the planetary carrier supports the planetary rotator at one location but not symmetrically at the opposite location. This asymmetric single-point support prevents the planetary rotator from inclining and generating thrust loads, resolving the contradiction between structural simplicity and reliability
2Stability of the object's composition
If the planetary rotator is supported at both tooth contact centers, then structural symmetry is improved, but durability deteriorates due to generated thrust loads
Solution Approach 1:
The patent extracts one support section from the symmetric dual-support configuration, leaving asymmetric single-point support. This removal eliminates the thrust load generation problem while maintaining sufficient structural stability for the planetary rotator's operation
Solution Approach 2:
The patent converts the potential harm of asymmetric support (which might seem to cause instability) into a benefit by deliberately designing the asymmetric single-point support to prevent thrust load generation. The asymmetry becomes the solution rather than the problem
3Reliability
If the support section is positioned at the inner peripheral side of the first tooth contact center, then the first moment becomes larger than the second moment, but the manufacturing precision requirements increase
Solution Approach 1:
The patent applies local quality by concentrating the support function at a specific location (inner peripheral side of the first tooth contact center) with optimized characteristics. The support section is designed with specific radial and axial dimensions (radial width of 2-5mm, axial width of 3-8mm) to achieve the desired moment balance and prevent inclination without requiring excessive manufacturing precision across the entire component
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 secures the durability of the valve timing adjusting device by preventing the inclination of the planetary rotator, thus reducing the risk of thrust loads and extending the lifespan of the bearing and gear components.
Implementation Method 1
a planetary rotator (30) that has a driving external gear section (52) and a driven external gear section (54) and changes a relative phase between the driven internal gear section and the driving internal gear section through sun-and-planet motion of the driving external gear section and the driven external gear section performed while the driving external gear section is geared with the driven internal gear section and the driven external gear section is geared with the driving internal gear section
Implementation Method 2
a mode of receiving the radial load differs depending on the numbers of teeth, diameters and the like of the gear sections. The inventor of the present invention discovered the problem that the planetary rotator is inclined from a proper axial direction depending on the mode of receiving the load
Data Source
AI summary
In a valve timing adjusting device, a support section of a planetary carrier supporting a planetary rotator to enable sun-and-planet motion is located on an inner peripheral side of a first center, which is a tooth contact center between a first gear section of the first rotator and a third gear section of the planetary rotator, and is separate from an inner peripheral side of a second center, which is a tooth contact center between a second gear section of the second rotator and a fourth gear section of the planetary rotator. First moment generated in the planetary rotator by a radial load applied to the third gear section by the first gear section is larger than second moment generated in the planetary rotator by a radial load applied to the fourth gear section by the second gear section.