Valve Timing Control Apparatus Torsion Spring Assembly

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Solution Overview

Problem

The conventional valve timing control apparatus for internal combustion engines requires labor-intensive assembly of the torsion spring before assembling the front plate to the housing body, making the process inconvenient and inefficient.

Innovation Solution

The apparatus includes a cutout portion on the front plate's sleeve portion that allows the torsion spring to be assembled after the front plate is attached to the housing body, with a design that prevents damage and abrasion by forming an obtuse angle at the inner circumferential end, enabling easy engagement of the torsion spring's end portion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the torsion spring is fixedly engaged in a through hole formed in a cylindrical sleeve portion before assembling the front plate to the housing body, then the torsion spring can be properly installed, but the assembly operation becomes labor-intensive and inconvenient

Engineering Contradiction:

Improvetorsion spring installation reliabilityVSAvoidassembly convenience

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent divides the assembly process into two independent stages: first assembling the front plate to the housing body, then separately installing the torsion spring through the cutout portion. This segmentation allows each component to be assembled in its optimal sequence, eliminating the need to pre-install the torsion spring and reducing assembly labor.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent extracts the torsion spring installation from the pre-assembly process by creating a cutout portion in the cylindrical sleeve. This allows the torsion spring to be installed after the front plate is already attached to the housing body, removing the constraint that previously required labor-intensive pre-installation.

Inventive Principle:

Principle #2Taking out (Extraction)

2Force

If the torsion spring is assembled before the front plate is attached to the housing body, then the biasing force can be properly established, but the assembly process requires additional labor to counteract the biasing force

Engineering Contradiction:

Improvebiasing force establishmentVSAvoidassembly efficiency

Core Design Contradiction:

ForceVSProductivity

Solution Approach 1:

The patent performs the front plate assembly to the housing body before installing the torsion spring. This preliminary action allows the structural base to be established first, and then the torsion spring is added in a subsequent step when its biasing force can be easily engaged without requiring labor to counteract it during assembly.

Inventive Principle:

Principle #10Preliminary action

3Reliability

If a through hole is used to engage the torsion spring, then the spring can be fixed, but the spring may suffer from damage and abrasion during assembly and operation

Engineering Contradiction:

Improvetorsion spring fixationVSAvoidtorsion spring damage and abrasion

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent creates a cutout portion with specific geometric characteristics (obtuse angle at the inner circumferential end) in the cylindrical sleeve. This local structural modification provides a favorable engagement surface for the torsion spring, reducing stress concentration and abrasion while maintaining reliable fixation.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent converts the potential harm of sharp edges in a through hole into a beneficial obtuse-angled cutout portion. This design change eliminates the risk of damage and abrasion to the torsion spring while maintaining effective engagement, turning a potential failure point into a protective feature.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 facilitates assembly without requiring labor to counteract the torsion spring's biasing force, enhancing productivity and reducing costs while preventing damage to the torsion spring during assembly.

Implementation Method 1

a torsion spring having one end portion fixed to the vane rotor and the other end portion bent in a radially outward direction of the torsion spring and fixedly engaged with the cutout portion

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

the vane rotor being rotatable relative to the housing body toward a phase-advance side by supplying hydraulic pressure to the phase-advance hydraulic chambers and discharging hydraulic pressure from the phase-retard hydraulic chambers

Methodology Applied

Scientific EffectHydraulic pressure: Pressure Increase

Data Source

PatentUS9151187B2Valve timing control apparatus for internal combustion engine

Publication Date: 2015.10.06 ASTEMO LTD

AI summary

A valve timing control apparatus including a vane rotor, a torsion spring having one end portion fixed to the vane rotor, and a front plate having a cylindrical sleeve portion and a cutout portion formed in the sleeve portion, the cutout portion having an end wall surface with which the other end portion of the torsion spring is engaged and a side wall surface opposed to the end wall surface, the cutout portion being formed such that a first straight line extending through the end wall surface toward a radial inside of the sleeve portion is located closer to a central axis of the sleeve portion than a second straight line extending through the side wall surface toward the radial inside of the sleeve portion.