Elastic Crawler Resin Cover Root Reinforcement

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Solution Overview

Problem

Existing elastic crawlers face issues with crack formation due to strain concentration at the interface between the elastic protrusion and resin cover member, either from embedding the resin or stress concentration at the base of the resin cover when external forces are applied.

Innovation Solution

An elastic crawler design featuring a resin cover member that covers the surface of the elastic protrusion except the root portion, with a reinforcing fiber part embedded along the side face of the root portion to prevent crack formation, and a thickened corner portion for increased endurance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the resin cover member is embedded in the elastic protrusion portion, then the resin cover member covers the top face and side faces of the protruding elastic protrusion portion, but strain is concentrated on the interface and a crack is likely to occur at the interface due to a difference in rigidity at the interface

Engineering Contradiction:
Improvecrack resistance at interfaceVSAvoidinterface strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The resin cover member is extracted from the embedded configuration and repositioned to sit on top of the elastic protrusion portion without biting into it. This removes the harmful interface contact that causes strain concentration and cracking, while the resin cover still performs its protective function of covering the top face and side faces of the elastic protrusion portion.

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If the resin cover member covers the entire surface of the elastic protrusion portion, then an interface at which a crack may occur does not exist between the elastic member and the resin member, but when an external force acts on the resin cover member, stress is likely to concentrate at the base of the elastic protrusion portion to cause a crack

Engineering Contradiction:
Improvecrack resistance at interfaceVSAvoidstress resistance at base
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The resin cover member is designed to cover only the top face and side faces of the elastic protrusion portion, deliberately leaving the base (root portion) exposed. This local differentiation allows the resin cover to protect against interface cracking while avoiding stress concentration at the base, as the external forces are distributed away from the vulnerable root portion.

Inventive Principle:
Principle #3Local quality

3Reliability

If the resin cover member is put on the elastic protrusion portion to cover the surface except the root portion, then an interface does not exist between the elastic protrusion portion and the resin cover member, but the root portion remains vulnerable to stress concentration

Engineering Contradiction:
Improvecrack resistance at interfaceVSAvoidstrength at root portion
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

A reinforcing fiber part is embedded in the root portion of the elastic protrusion portion to create a composite structure. This combines the elasticity of the elastic material with the high strength of the fiber material, providing crack resistance at the root portion without creating an interface with the resin cover member.

Inventive Principle:
Principle #40Composite materials

Data Source

PatentEP4324727A1Elastic crawler
Publication Date: 2024.02.21 BRIDGESTONE CORP
  • EP4324727A1 patent drawingFigure 1~2
  • EP4324727A1 patent drawingFigure 3
  • EP4324727A1 patent drawingFigure 4~5

AI summary

[Object] To provide an elastic crawler which can prevent occurrence and progression of a crack in an elastic protrusion portion to achieve high endurance of a guide protrusion. [Solving Means] An elastic crawler 10 includes a plurality of elastic protrusion portions 13 formed in a manner protruding on an inner circumferential face of a crawler main body 11, which is made of an elastic material and formed in an endless belt shape, at regular intervals in a crawler circumferential direction, and a resin cover member 14 made of a resin material and covering a surface of each elastic protrusion portion 13, and the resin cover member 14 covers the elastic protrusion portion 13 to form a guide protrusion 15. In the elastic crawler 10, the resin cover member 14 of the guide protrusion 15 is put on the elastic protrusion portion 13 to cover the surface of the elastic protrusion portion 13 except a root portion 13r, and a reinforcing fiber part 25 is embedded at least in the root portion 13r of the elastic protrusion portion 13 along a side face 13b of the elastic protrusion portion 13.