Valve Timing Lock Mechanism Centrifugal Release
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Solution Overview
Problem
Existing valve opening/closing timing control apparatuses face challenges in rapid lock release due to shear forces acting on lock members, requiring time for hydraulic pressure to change the relative rotational phase, leading to delayed lock release.
Innovation Solution
A valve opening/closing timing control apparatus with a driving side rotational body and a driven side rotational body, featuring an advanced angle chamber and a retarded angle chamber, and a lock mechanism with first and second lock members biased to engage with recesses, where the first release rotational frequency of the first lock member is set lower than the second, allowing centrifugal force to disengage the lock members and controlling the relative phase to minimize shear force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydraulic oil is supplied to lock recesses to release lock members, then lock members can be disengaged, but rapid lock release cannot be achieved due to shear force acting on lock members
Solution Approach 1:
The patent applies preliminary action by controlling the relative rotational phase before lock release to a specific phase where shear force on lock members is minimized. By pre-positioning the system at an optimal phase angle, the lock members can be disengaged more rapidly when hydraulic oil is supplied, as the adverse shear force is already reduced. This preliminary phase control enables faster lock release while maintaining reliable engagement during normal operation.
2Ease of operation
If time is required for hydraulic pressure to change relative rotational phase, then lock release control can be achieved, but lock release time is delayed
Solution Approach 1:
The control system performs preliminary action by pre-controlling the relative rotational phase to an optimal position before initiating lock release. This advance phase positioning reduces the time required for hydraulic pressure to effect lock member disengagement, as the system is already in a favorable configuration. The preliminary phase control eliminates delays that would otherwise be required to overcome adverse shear forces during phase change.
Solution Approach 2:
The patent applies parameter changes by optimizing the relative rotational phase angle as a control parameter. By changing the phase angle to a specific value where shear force is minimized, the system achieves rapid lock release. This parameter optimization transforms the lock release process from a time-consuming operation to a rapid response, while maintaining ease of control through hydraulic actuation.
3Device complexity
If a single lock member is used, then device complexity is reduced, but lock release cannot be achieved under high shear force conditions
Solution Approach 1:
The patent applies preliminary action by controlling the relative rotational phase before lock release to a specific phase where shear force on lock members is minimized. By pre-positioning the system at an optimal phase angle, the lock members can be disengaged more rapidly when hydraulic oil is supplied, as the adverse shear force is already reduced. This preliminary phase control enables faster lock release while maintaining reliable engagement during normal operation.
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
Enables rapid lock release without relying on hydraulic fluid pressure for the first lock member, suppressing shear forces and allowing quicker phase control, thus improving the efficiency of valve timing control.
Implementation Method 1
As a rotational frequency of the driving side rotational body to bring the first and second lock members into a lock released state by a centrifugal force, a first release rotational frequency of the first lock member is set to be lower than a second release rotational frequency of the second lock member
Data Source
AI summary
A valve opening/closing timing control apparatus includes: a driving side rotational body synchronously rotating with a crankshaft of an internal combustion engine; a driven side rotational body arranged in the driving side rotational body to share a rotational axis therewith and integrally rotating with a camshaft; advanced angle and retarded angle chambers defined between the driving side and driven side rotational bodies; a lock mechanism maintaining a relative rotational phase between the driving side and driven side rotational bodies by separately biasing first and second lock members to be engaged with first and second recesses; and a fluid controller releasing the locked state by supplying a hydraulic fluid to the first and second recesses, and controlling the relative rotational phase by supplying and discharging the hydraulic fluid to the advanced angle and retarded angle chambers.