Wrapped V-Belt Notch Structure for Crack-Resistant Bending

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Solution Overview

Problem

Wrapped V-belts with notch portions suffer from early fracture due to localized stress concentration at the notch tops, leading to crack generation and reduced durability.

Innovation Solution

A wrapped V-belt design featuring a compression layer with a fabric-laminated body layer, where the notch portions are not covered by the outside cloth, with the notch tops positioned in the fabric-laminated body layer to act as a reinforcing layer, enhancing crack resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If notch portions are formed by mechanical cutting or punching on the belt inner surface side, then bendability is enhanced and bending rigidity is reduced, but cracks generate from the top of the notch portions due to localized stress concentration, causing early fracture

Engineering Contradiction:
ImprovebendabilityVSAvoidcrack resistance
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent applies composite materials by combining rubber composition with fabric reinforcement. The fabric-laminated body layer is formed by laminating multiple fabric pieces treated with rubber composition, creating a composite structure that provides both flexibility and strength. This composite construction prevents crack propagation while maintaining bendability, as the fabric layers distribute stress throughout the material rather than concentrating it at notch tops.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent applies local quality by positioning the fabric-laminated body layer specifically at the top regions of the notch portions, where stress concentration occurs during bending. The fabric pieces are strategically laminated at these critical locations to provide localized reinforcement exactly where needed, while other areas of the belt maintain their original properties for optimal performance.

Inventive Principle:
Principle #3Local quality

2Device complexity

If the top of the notch portion is positioned in the compression rubber layer, then the structure is simpler, but the deforming stress concentrates at the rubber surface, leading to crack generation

Engineering Contradiction:
Improvestructural complexityVSAvoidnotch portion resistance
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent introduces a fabric-laminated body layer as a composite material within the compression layer structure. This fabric reinforcement, treated with rubber composition and laminated in multiple layers, creates a composite structure that distributes deforming stress throughout the fabric network rather than concentrating it at the rubber surface, thereby preventing crack generation while maintaining structural integrity.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The fabric-laminated body layer acts as an intermediary between the compression rubber layer and the outside cloth. By positioning the fabric-reinforced layer at the notch top, it serves as a stress-distributing mediator that prevents direct stress concentration at the rubber surface, thereby protecting against crack initiation while allowing the overall structure to remain relatively simple.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 solution effectively suppresses crack generation and improves notch portion resistance by distributing deforming stress and increasing the rigidity of the compression layer, thereby extending the belt's lifespan.

Implementation Method 1

The solution effectively suppresses crack generation and improves notch portion resistance by distributing deforming stress and increasing the rigidity of the compression layer

Methodology Applied
Scientific EffectStress distribution:

Implementation Method 2

a fabric-laminated body layer in which a plurality of pieces of a rubber composition-attached fabric are laminated and adhered to each other

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP3290743B1Wrapped v-belt and method for manufacturing wrapped v-belt
Publication Date: 2021.08.25 MITSUBOSHI BELTING LTD
  • EP3290743B1 patent drawingFigure 1(A)~1(B)
  • EP3290743B1 patent drawingFigure 2(A)~2(B)
  • EP3290743B1 patent drawingFigure 3(A)~3(B)

AI summary

The present invention relates to a wrapped V-belt (100) containing: a belt main body (150) containing a compression layer (110) disposed on a belt inner surface side and containing a compression rubber layer (111) and a fabric-laminated body layer (120) in which a plurality of pieces of a rubber composition-attached fabric are laminated and adhered to each other, a tension rubber layer (130) disposed on a belt outer surface side and a tension member (140) buried between the compression layer (110) and the tension rubber layer (130); and an outside cloth (160) that covers a periphery of the belt main body (150) over an entire length in a belt circumferential direction, in which the compression layer (110) has a plurality of notch portions (170) to be open on the belt inner surface side and not covered with the outside cloth (160), and the notch portion (170) has a top positioned on the most belt outer surface side in a belt thickness direction and disposed in the fabric-laminated body layer (120).