Valve Timing Gear Filtration for Low-Speed Contaminant Protection
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Solution Overview
Problem
Existing valve timing adjustment devices for internal combustion engines face issues with small foreign matter entering the gear meshing portion, particularly under low temperature or low speed conditions, leading to potential gear wear and lockage due to inadequate trapping of contaminants by centrifugal force in reduction mechanisms like wave gear mechanisms.
Innovation Solution
Incorporating a filter unit with multiple axial holes in the lubricating fluid flow path connected to the supply hole, which captures foreign matter before it reaches the gear meshing area, utilizing a mesh filter unit made of metal to restrict entry into the reduction mechanism's internal and external gear portions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a reduction mechanism like wave gear mechanism is used in valve timing adjustment device, then the relative rotation phase between driving and driven rotating bodies can be changed, but small foreign matter can enter the gear meshing portion particularly under low temperature or low speed conditions, leading to gear wear and lockage
Solution Approach 1:
The filter unit is installed in the lubricating fluid supply path before the lubricating fluid reaches the gear meshing portion. This preliminary filtration action captures foreign matter in advance, preventing it from entering the gear meshing area where it could cause wear or lockage, especially under low temperature or low speed conditions when centrifugal force is insufficient.
Solution Approach 2:
The filter unit acts as an intermediary element between the lubricating fluid supply and the gear meshing portion. It mediates by capturing foreign matter contained in the lubricating fluid, allowing the lubricating fluid to reach the gear mechanism while blocking harmful contaminants, thus protecting the gear teeth from damage.
2Reliability
If centrifugal force is used to trap foreign matter in the reduction mechanism, then foreign matter can be trapped during normal operation, but under low temperature or low speed conditions, the centrifugal force is insufficient and foreign matter enters the gear meshing portion
Solution Approach 1:
Instead of relying on centrifugal force that becomes insufficient at low speeds, the filter unit performs preliminary filtration of the lubricating fluid before it enters the gear mechanism. This preliminary action ensures foreign matter is captured regardless of the rotation speed or temperature conditions, providing reliable protection during both high and low speed operation.
Solution Approach 2:
The patent replaces the centrifugal force-based trapping mechanism with a filter unit-based mechanical filtration system. The filter unit with its mesh structure provides passive filtration that does not depend on rotation speed or centrifugal force, thereby eliminating the performance degradation observed under low speed or low temperature conditions.
3Reliability
If a filter unit is added to capture foreign matter in the lubricating fluid, then foreign matter entry into gear meshing portion is prevented, but the device complexity increases
Solution Approach 1:
The filter unit is integrated into the existing lubricating fluid supply path of the valve timing adjustment device. By utilizing the already-present lubrication system infrastructure, the filter unit adds filtration functionality without requiring separate fluid delivery mechanisms, thereby minimizing the increase in device complexity while achieving reliable foreign matter prevention.
Solution Approach 2:
The filter unit is designed to be nested within the existing structure of the valve timing adjustment device, specifically within the lubricating fluid supply path. This nesting approach allows the filter to be housed within the existing mechanical envelope without adding significant external complexity, maintaining a compact and integrated design.
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
Effectively prevents foreign matter from entering the gear meshing area, even under low centrifugal force conditions, thereby preventing gear wear and lockage, and ensuring continuous operation by capturing small foreign particles in a compact and simple structural configuration.
Implementation Method 1
a filter unit capable of capturing a foreign matter contained in lubricating fluid supplied into the reduction mechanism
Implementation Method 2
Lubricating oil may be supplied into a reduction mechanism of the valve timing adjustment device
Data Source
AI summary
A valve timing adjustment device includes: a driving rotating body that rotates with a crankshaft; a driven rotating body that rotates with a camshaft; a reduction mechanism configured to change a relative rotation phase of the driving rotating body and the driven rotating body by a driving force of an actuator; and a filter unit capable of capturing a foreign matter contained in lubricating fluid supplied into the reduction mechanism. The reduction mechanism includes: an internal gear portion having internal teeth formed inward in a radial direction, and an external gear portion having external teeth formed outward in the radial direction to mesh with the internal teeth. The driven rotating body has a supply hole penetrating in an axial direction. The filter unit has holes penetrating in the axial direction, and the holes are arranged in a flow path of the lubricating fluid connected to the supply hole.