Valve Timing Eccentric Member Arc Segmentation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing valve opening-closing timing control devices face challenges in reducing noise due to the complexity and cost of forming elliptical displacement regulation portions on the drive shaft, which are necessary to regulate gear displacement orthogonal to the biasing direction.
Innovation Solution
A valve opening-closing timing control device with a phase adjustment mechanism that includes an eccentric member with a first and second arc portion and a spaced portion on its outer peripheral surface, which reduces noise by regulating gear displacement and preventing contact between internal and external teeth, using a hypo-cycloid gear deceleration mechanism to alter the relative rotational phase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If displacement regulation portions are formed into elliptic shapes by grinding or cutting, then gear displacement orthogonal to biasing direction is regulated effectively, but manufacturing cost increases
Solution Approach 1:
The displacement regulation portions are segmented into multiple arc portions (first arc portion, second arc portion, third arc portion) instead of forming a continuous elliptic shape. Each arc portion is disposed at different angular positions around the drive shaft, collectively achieving the displacement regulation function while allowing simpler circular cross-section manufacturing
Solution Approach 2:
The invention uses arc-shaped portions with specific radius of curvature to regulate displacement. Each arc portion has a radius of curvature that is 0.05 to 0.15 times the outer diameter of the drive shaft, creating effective displacement regulation through curved surfaces that are easier to manufacture than full elliptic shapes
2Reliability
If elliptic displacement regulation portions are formed on drive shaft, then responsiveness and noise reduction are improved, but device complexity increases
Solution Approach 1:
The displacement regulation function is achieved by segmenting the regulation portions into multiple discrete arc portions arranged around the drive shaft. This segmentation simplifies the overall structure compared to continuous elliptic formations while maintaining the ability to regulate gear displacement in orthogonal directions
Solution Approach 2:
Instead of making the drive shaft itself elliptic in cross-section (which would increase complexity), the invention inverts the approach by adding discrete arc portions to a circular drive shaft. The arc portions protrude radially outward and provide the necessary displacement regulation without requiring the drive shaft to have a complex elliptic geometry
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 solution effectively reduces noise and improves the responsiveness of the valve opening-closing timing control device while simplifying the manufacturing process by using a hypo-cycloid gear deceleration mechanism and precise arc-shaped surfaces, reducing the need for expensive elliptical shape formation.
Implementation Method 1
a spring which applies biasing force in a direction where a part of the external tooth portion of the inner gear is engaged with a part of the internal tooth portion of the ring gear
Implementation Method 2
A ball bearing is disposed between an inner periphery of the inner gear and the drive shaft, and the drive shaft and the inner gear are relatively rotatable around the eccentric axis
Implementation Method 3
an eccentric member being rotated by the electric actuator and having an outer peripheral surface centered on an eccentric axis in a posture parallel to the rotational axis and with a predetermined amount of eccentricity with respect to the rotational axis
Data Source
AI summary
A phase adjustment mechanism for setting a relative rotational phase of a driven-side rotational body to a drive-side rotational body of a valve opening-closing timing control device includes a output gear around a rotational axis, an input gear being rotated around an eccentric axis, and an eccentric member. The eccentric member includes an outer peripheral surface with a first arc portion, a second arc portion, a plate spring fitted between the first arc portion and the second arc portion, and a spaced portion. Each of the first arc portion and the second arc portion is disposed from a position less than 90 degrees to a position more than 90 degrees as a central angle with respect to the eccentric axis from a biasing direction of the plate spring in the peripheral direction.