Variable Valve Mechanism Outer Arm Through-Hole Design
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Solution Overview
Problem
Existing variable valve mechanisms face challenges in achieving a balance between the strength of the outer arm and the swinging amount of the inner arm, as the installation of a lost motion spring either restricts the thickness of the upper or lower portion of the outer arm, leading to reduced strength and limited swinging capacity.
Innovation Solution
A variable valve mechanism with a through-hole in the outer arm, allowing the lost motion spring's extending portion to pass through, where connecting portions are positioned on both sides of the hole, enabling high strength and a large swinging amount without compromising the structure's integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the lost motion spring is installed from the outside of the outer arm through a portion above the outer arm onto an inner arm, then the lost motion spring can be installed, but the thickness of the upper portion of the outer arm is restricted and the strength of the outer arm may decrease
Solution Approach 1:
The patent changes the installation dimension of the lost motion spring from the vertical direction (above/below the outer arm) to the horizontal direction (through the width of the outer arm). The extending portion of the lost motion spring passes through a through-hole formed in the width direction of the outer arm, allowing the spring to be installed from the outside through the space to the inside, thereby avoiding restrictions on the thickness of the upper or lower portions of the outer arm and maintaining its strength.
2Ease of manufacture
If the lost motion spring is installed from a portion below an outer arm, then the lost motion spring can be installed, but the thickness of the lower portion of the outer arm is restricted and the strength of the outer arm may decrease
Solution Approach 1:
The patent changes the installation dimension of the lost motion spring from the vertical direction (above/below the outer arm) to the horizontal direction (through the width of the outer arm). The extending portion of the lost motion spring passes through a through-hole formed in the width direction of the outer arm, allowing the spring to be installed from the outside through the space to the inside, thereby avoiding restrictions on the thickness of the upper or lower portions of the outer arm and maintaining its strength.
3Length of moving object
If the length of the slot is increased to allow larger swinging amount of the inner arm, then the swinging amount increases, but the strength of the outer arm may decrease
Solution Approach 1:
The patent replaces the slot structure (extending in the swinging direction of the inner arm) with a through-hole structure (extending in the width direction of the outer arm). This dimensional change allows the extending portion of the lost motion spring to pass through the through-hole and swing within it, providing sufficient swinging amount for the inner arm without creating a long slot that would compromise the outer arm's strength.
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 enhances the strength of the outer arm while allowing a sufficient swinging amount of the inner arm, reducing weight and maintaining structural integrity without significant increases in the through-hole length.
Implementation Method 1
a lost motion spring that biases the inner arm toward a cam in the non-coupled state
Data Source
AI summary
A variable valve mechanism of an internal combustion engine includes an outer arm, an inner arm, a switching device that switches between a coupled state and a non-coupled state, and a lost motion spring. The lost motion spring has an extending portion extending from the outside of the space to the inside of the space. The extending portion has a contact portion that is in contact with the inner arm in the space and being configured to swing in conjunction with swinging of the inner arm. A through-hole is formed in a vertically intermediate portion of the outer arm such that connecting portions are provided at vertically opposite sides of the through-hole, and a portion of the extending portion, a swinging amount of which is smaller than that of the contact portion, passes through the through-hole that allows the portion to swing therein.