Valve Timing Spool Breathing Hole Relocation
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Solution Overview
Problem
Existing valve timing adjustment devices face issues with hydraulic oil leakage and decreased responsiveness due to difficulties in sealing between pressure accumulation and breathing holes, leading to potential malfunctions and reduced efficiency.
Innovation Solution
The proposed valve timing adjustment device incorporates a sleeve and spool configuration with a breathing hole located outside the sleeve, allowing the pressure in the variable volume space to equal atmospheric pressure, preventing hydraulic oil leakage and enhancing responsiveness by reducing the oil path length and eliminating the need for a separate partitioning member inside the spool.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a partitioning member is installed inside the spool to separate pressure accumulation space and breathing hole, then sealing between pressure accumulation and breathing holes is improved, but device complexity increases and manufacturing precision requirements increase
Solution Approach 1:
The breathing hole is extracted from the internal space of the spool and relocated to the outer surface of the sleeve. This eliminates the need for partitioning members inside the spool, simplifying the structure while maintaining sealing performance. The breathing hole now communicates with the atmosphere through the sleeve wall rather than requiring internal separation.
Solution Approach 2:
The breathing hole is nested within the sleeve structure itself, utilizing the sleeve wall as the communication path to the atmosphere. This integrates the breathing function into the existing sleeve component without adding separate partitioning elements, reducing overall device complexity.
2Volume of moving object
If the breathing hole is located inside the spool, then the structure is compact, but sealing difficulties cause hydraulic oil leakage and reduced reliability
Solution Approach 1:
The breathing hole is extracted from the problematic internal spool location and repositioned to the outer surface of the sleeve, eliminating sealing difficulties while maintaining compact overall device dimensions through the integrated sleeve structure.
3Speed
If the oil path length is reduced to improve responsiveness, then the spool position changes faster, but sealing between pressure accumulation and breathing holes becomes more difficult
Solution Approach 1:
By extracting the breathing hole to the outer surface of the sleeve, the patent achieves short oil paths for rapid spool response while eliminating the sealing conflicts that would arise from having the breathing hole inside the spool, thus maintaining both responsiveness and reliability.
4Reliability
If a separate partitioning member is used inside the spool, then pressure accumulation and breathing spaces are separated, but manufacturing precision requirements increase
Solution Approach 1:
The sleeve structure merges the functions of housing and breathing hole provision into a single component. The breathing hole is formed directly in the sleeve wall, eliminating the need for separate partitioning members and reducing manufacturing and assembly precision requirements.
Solution Approach 2:
The breathing hole is nested within the sleeve structure itself, utilizing the sleeve wall thickness to provide the communication path to atmosphere. This integration eliminates separate partitioning components and reduces the number of precision assembly operations required.
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 configuration improves the responsiveness and reliability of the valve timing adjustment device by ensuring smooth spool reciprocation and maintaining hydraulic oil pressure, thereby enhancing the overall performance and preventing malfunctions.
Implementation Method 1
The sleeve includes a breathing hole that communicates between the variable volume space and an atmosphere and is located at an outside of the inside space of the sleeve
Data Source
AI summary
A spool is configured to reciprocate at an inside space of a sleeve and includes: a spool tube; a spool cover, which closes an end portion of the spool tube located on a camshaft side; a pressure accumulation space, which is formed at an inside of the spool tube; a supply passage, which is configured to connect between the pressure accumulation space and a supply port; a control passage, which is configured to connect between the pressure accumulation space and a primary control port; and a control passage, which is configured to connect between the pressure accumulation space and a secondary control port. A variable volume space is formed between the spool cover and a sleeve bottom. The sleeve includes a breathing hole at an outside of the inside space while the breathing hole is a hole that communicates between the variable volume space and the atmosphere.