Valve Timing Control Apparatus Dual Lock Mechanism

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Solution Overview

Problem

Existing valve timing control apparatuses face challenges in maintaining stable operation and preventing noise during low-speed idling operations due to reduced feeding pressure, especially when the size and capacity of the working fluid pump are reduced, leading to instability and fluttering of the driven-side rotary body.

Innovation Solution

A valve timing control apparatus with a dual lock mechanism system that allows for precise control of the relative rotational phase between the driving-side and driven-side rotary bodies, enabling stable operation at low feeding pressures by restraining the phase to predetermined positions, and includes a fluid switchover mechanism for independent control of the lock mechanisms without affecting each other's operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stress or pressure

If the size and capacity of the working fluid pump are reduced, then the feeding pressure of working fluid is reduced, but the stability of the driven-side rotary body deteriorates due to fluttering and noise during low-speed idling operations

Engineering Contradiction:

Improvefeeding pressureVSAvoidstability of driven-side rotary body

Core Design Contradiction:

Stress or pressureVSStability of the object's composition

Solution Approach 1:

The lock mechanism proactively restrains the relative rotational phase between the driving-side and driven-side rotary bodies to predetermined phases before instability occurs during low-speed idling. By pre-establishing stable phase positions, the system prevents fluttering and noise rather than reacting to them after they begin.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces the purely hydraulic control system with a hybrid system that incorporates mechanical locking through the lock mechanism. This mechanical constraint provides additional stability to the driven-side rotary body, compensating for the reduced feeding pressure caused by the smaller pump capacity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Device complexity

If a single lock mechanism is used to restrain the relative rotational phase, then the structure is simple, but the adaptability to different operation conditions deteriorates

Engineering Contradiction:

Improvestructure complexityVSAvoidadaptability to operation conditions

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The locking function is segmented into multiple independent lock mechanisms, each capable of restraining the relative rotational phase to different predetermined phases. This segmentation allows the system to adapt to various operation conditions by activating appropriate lock mechanisms without increasing overall structural complexity, as each mechanism is identical and modular.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system dynamically selects which lock mechanism to activate based on the current operating conditions. The control unit can switch between different lock mechanisms to restrain the relative rotational phase to different phases, providing adaptability to varying engine operating conditions while maintaining a relatively simple overall structure.

Inventive Principle:

Principle #15Dynamics

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 dual lock mechanism system ensures stable idling and startup conditions for internal combustion engines, preventing noise and maintaining precise valve timing control even at low feeding pressures, thereby improving engine performance and reducing emissions.

Implementation Method 1

a fluid pressure chamber formed by the driving-side rotary body and the driven-side rotary body and partitioned into a retard angle chamber and an advance angle chamber by a partitioning portion

Methodology Applied

Scientific EffectFluid pressure: Pressure Increase

Implementation Method 2

by provision of a torsion spring for applying torque in the advance angle direction to the driven-side rotary body

Methodology Applied

Scientific EffectTorsion spring: Torsion Spring

Data Source

PatentUS8820278B2Valve timing control apparatus

Publication Date: 2014.09.02 AISIN SEIKI KK

AI summary

A valve timing control apparatus includes a driving-side rotary body, a driven-side rotary body, a fluid pressure chamber partitioned into a retard angle chamber and an advance angle chamber by a partitioning portion provided in at least one of the driving-side rotary body and the driven-side rotary body, a fluid control mechanism for controlling feeding of working fluid from a working fluid pump for feeding the working fluid to the fluid pressure chamber and controlling also discharging of the working fluid from the fluid pressure chamber, a first lock mechanism capable of restraining a relative rotational phase to a first predetermined phase between a most retarded angle phase and a most advanced angle phase, and a second lock mechanism capable of restraining the relative rotational phase to a second predetermined phase different from the first predetermined phase.