Valve Timing Rotor Sleeve Fit for Misalignment-Tolerant Fixing
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Solution Overview
Problem
Integrated valve timing adjustment devices face reliability issues due to manufacturing errors causing misalignment between components, leading to a decrease in the axial force required to fix the hydraulic oil control valve, which affects the device's responsiveness and reliability.
Innovation Solution
The valve timing adjustment device incorporates a design where the radial dimension difference between the shaft fixing hole and the fixing portion is set greater than the total predetermined coaxiality, allowing for the absorption of misalignment errors and ensuring a sufficient axial force for fixing the hydraulic oil control valve, thereby enhancing reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the radial dimension difference between the shaft fixing hole and the fixing portion is reduced to minimize misalignment, then manufacturing precision is improved, but the axial force required to fix the hydraulic oil control valve decreases, worsening reliability
Solution Approach 1:
The patent applies beforehand cushioning by intentionally designing a radial dimension difference (clearance) between the shaft fixing hole and the fixing portion that is greater than the total predetermined coaxiality. This pre-established clearance acts as a buffer that absorbs misalignment errors from manufacturing, ensuring that the axial fixing force remains sufficient even when coaxiality deviations occur, thus preventing reliability degradation before it can happen.
2Reliability
If the radial dimension difference is increased to absorb misalignment errors, then reliability is improved, but manufacturing precision requirements become more stringent, worsening manufacturing complexity
Solution Approach 1:
The patent applies parameter changes by modifying the radial dimension parameters of the shaft fixing hole and fixing portion. Specifically, it sets the radial dimension difference to be greater than the total predetermined coaxiality, thereby changing the dimensional parameters to create a clearance that absorbs misalignment. This parameter adjustment ensures sufficient axial fixing force while maintaining reasonable manufacturing precision requirements.
3Manufacturing precision
If tight tolerances are applied to ensure precise alignment, then manufacturing precision is improved, but device complexity increases due to stricter quality control requirements
Solution Approach 1:
The patent reduces device complexity by applying beforehand cushioning through intentional clearance design. Instead of requiring tight tolerances and complex quality control processes to ensure precise alignment, the invention pre-establishes a radial dimension difference that naturally absorbs misalignment errors. This approach simplifies quality control requirements while maintaining adequate alignment accuracy.
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 effectively suppresses the decrease in axial force and reliability issues by absorbing misalignment errors, ensuring the hydraulic oil control valve is securely fixed with an axial force equal to or higher than a predetermined value, thus improving the device's responsiveness and reliability.
Implementation Method 1
configured to alter a phase of the one of the drive shaft and the driven shaft relative to the other of the drive shaft and the driven shaft according to a pressure of a hydraulic oil supplied from a hydraulic oil supply source
Implementation Method 2
The spool is configured to slidably move in the axial direction within the sleeve
Data Source
AI summary
A valve timing adjustment device includes a vane rotor and a hydraulic oil control valve. The vane rotor is fixed to an end portion of one of a drive shaft and a driven shaft and defines a through hole. The hydraulic oil control valve includes a sleeve and a spool. The sleeve includes a body portion in the through hole and a fixing portion fixed into a shaft fixing hole defined in the one. At least a portion of the through hole is sealed by the body portion. A difference between a radial dimension of the shaft fixing hole and a radial dimension of the fixing portion is greater than a total of a predetermined coaxiality between the through hole and the shaft fixing portion and a predetermined coaxiality between the body portion and the fixing portion.