Toothed belt
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Solution Overview
Problem
Toothed belts used in environments where oil is present, such as for overhead camshafts in automobile engines, experience strength degradation due to oil adhesion, which existing technologies fail to adequately address.
Innovation Solution
A toothed belt design featuring a rubber body with integrated helical cord made of twisted high-strength glass fibers and a binder containing maleimide-based or polyisocyanate compounds, along with a powdery inorganic filler, and a surface-coating rubber layer with hydrogenated nitrile-butadiene rubber, which enhances adhesion and resistance to strength loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional toothed belt is used in an environment where oil adheres to it, then the belt can operate initially, but the strength of the belt degrades over time due to oil adhesion
Solution Approach 1:
The patent applies silane-modified polybutadiene rubber which has inherent oil resistance properties. The silane modification creates a chemical structure that repels oil, converting the harmful oil environment into a non-degradative condition. This allows the belt to maintain its strength and service life even when exposed to oil, effectively using the material's chemical properties to counteract the harmful environmental factor.
Solution Approach 2:
The patent uses a composite rubber composition combining silane-modified polybutadiene rubber with specific reinforcing fillers and processing aids. This composite material structure provides both the elasticity needed for belt operation and the oil resistance required for long-term durability in oily environments, resolving the contradiction between initial functionality and long-term strength maintenance.
2Strength
If the number of second twists of the cord is increased to maintain strength, then the belt strength is improved, but the manufacturing complexity and cost increase
Solution Approach 1:
Instead of increasing the number of twists to maintain strength, the patent changes the material parameter by using silane-modified polybutadiene rubber with superior inherent strength and oil resistance properties. This parameter change in material composition allows the belt to maintain high strength without requiring excessive cord twisting, thereby reducing manufacturing complexity while achieving the desired strength level.
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 design significantly reduces strength degradation of the toothed belt when exposed to oil, maintaining belt integrity and performance over time.
Implementation Method 1
the binder containing a rubber component, at least either a maleimide-based compound or a polyisocyanate compound
Implementation Method 2
a surface of the reinforcing fabric facing opposite to the toothed belt body is coated with a surface-coating rubber layer made of a rubber composition containing a rubber component including hydrogenated nitrile-butadiene rubber as a main part
Implementation Method 3
the cord is made of a twisted yarn including a band-like material, the band-like material including a filament bundle of high-strength glass fibers integrated together through a binder
Data Source
AI summary
A cord of a toothed belt is made of a twisted yarn including a band-like material. The band-like material includes a filament bundle of high-strength glass fibers integrated together through a binder. The binder contains a rubber component, at least either a maleimide-based compound or a polyisocyanate compound, and a powdery inorganic filler. A surface of a reinforcing fabric facing opposite to the toothed belt body is coated with a surface-coating rubber layer made of a rubber composition containing a rubber component including hydrogenated nitrile-butadiene rubber as a main part.