Valve Timing Adjustment Apparatus Tilt Control
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Solution Overview
Problem
Existing valve timing adjustment apparatuses suffer from reduced durability due to excessive wear caused by gear rattle and increased contact pressure in ball bearing rollers, leading to a shorter lifespan.
Innovation Solution
A valve timing adjustment apparatus with a single-row ball bearing roller and a planetary carrier that tilts at a smaller angle, reducing contact pressure and wear by distributing the radial load over a smaller contact area, and utilizing an eccentric geared rotor for enhanced contact area without increasing thrust on the inner ring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a two-row ball bearing roller is used to regulate tilt, then the tilt of the inner ring is received through rolling elements in two circumferences, but the total contact area becomes large causing increased contact pressure and wear
Solution Approach 1:
The bearing roller is segmented into two distinct regions: a first region with rolling elements arranged in two rows for tilt regulation, and a second region with rolling elements arranged in a single row for reduced contact pressure. This segmentation allows each region to fulfill its specific function without compromising the other.
Solution Approach 2:
Different regions of the bearing roller are given different local qualities: the first region has higher rolling element density (two rows) for effective tilt regulation, while the second region has lower rolling element density (single row) for reduced contact pressure and wear. This local differentiation optimizes both tilt control and durability.
2Force
If the planetary carrier is tilted around a specific point to support radial load, then the geared rotor tilts together with the planetary carrier, but gear rattle occurs at meshing locations causing increased wear
Solution Approach 1:
The biased element acts as an intermediary between the planetary carrier and the geared rotor. It transmits the radial load while maintaining a predetermined clearance that prevents direct contact and gear rattle, thereby reducing wear at meshing locations while still supporting the radial load effectively.
Solution Approach 2:
The biased element provides beforehand cushioning by maintaining a predetermined clearance between the planetary carrier and geared rotor. This clearance prevents harmful gear rattle before it can occur, cushioning against impact loads and reducing wear at the meshing locations of the geared rotor.
3Stability of the object's composition
If multiple rows of rolling elements are used to receive tilt, then tilt regulation effects become great, but contact pressure occurs in a large area causing increased wear and reduced lifespan
Solution Approach 1:
The bearing roller is segmented into two distinct regions: a first region with rolling elements arranged in two rows for tilt regulation, and a second region with rolling elements arranged in a single row for reduced contact pressure. This segmentation allows each region to fulfill its specific function without compromising the other.
Solution Approach 2:
Different regions of the bearing roller are given different local qualities: the first region has higher rolling element density (two rows) for effective tilt regulation, while the second region has lower rolling element density (single row) for reduced contact pressure and wear. This local differentiation optimizes both tilt control and durability.
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 improves durability by minimizing wear on both the geared rotor and the ball bearing roller, reducing the risk of gear rattle and extending the lifespan of the apparatus while maintaining effective valve timing adjustment.
Implementation Method 1
a ball bearing roller that is supported by the second rotor and supports the planetary carrier in the radial direction from an outside of the planetary carrier
Implementation Method 2
a geared rotor meshing with the first gear portion and the second gear portion and moving in planetary motion to adjust a relative phase between the first rotor and the second rotor
Data Source
AI summary
A planetary carrier supports a geared rotor from an inside in a radial direction, and receives a radial load in a first region, which is offset to one end from a center position in an axial direction. A ball bearing roller supports the planetary carrier from an outside in the radial direction in a second region, which is offset to an other end from the center position. The ball bearing roller is a single-row ball bearing roller that has an outer ring supported by a drive rotor, an inner ring which supports the planetary carrier, and a plurality of rolling elements which are rotatably installed in a single row to be in contact with and between the outer and the inner rings. The geared rotor is tilted relative to the axial direction, and contacts a driven rotor in the axial direction. An angle of the geared rotor relative to the axial direction is set to be smaller than a maximum allowable angle at which the inner ring is allowed to be tilted relative to the axial direction.