Cast Idler Wheel Structure for Even Load Distribution

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Solution Overview

Problem

Existing idler wheels in track-type machines experience premature failure due to suboptimal force distribution, leading to reduced durability and increased manufacturing costs, while standard designs often require labor-intensive and expensive forging processes.

Innovation Solution

A fully cast idler wheel design featuring an annular rim portion, annular hub portion, and offset V-shaped beams that distribute loads evenly, manufactured via casting to reduce material usage and weight.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an overbuilt idler wheel is used to ensure durability and robustness, then reliability is improved, but weight increases and manufacturing costs increase

Engineering Contradiction:

ImprovedurabilityVSAvoidweight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The idler wheel employs varying wall thicknesses in different regions to provide localized strength where needed. The hub portion has a first wall thickness, while the rim portion has a second wall thickness that differs from the hub, allowing each region to be optimized for its specific functional requirements rather than uniformly overbuilding the entire structure.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The idler wheel integrates multiple material properties through its complex geometry and varying thickness profiles, creating a composite-like structure where different regions contribute different mechanical properties. This allows the single-piece structure to achieve the durability of overbuilt designs while minimizing overall material usage and weight.

Inventive Principle:

Principle #40Composite materials

2Reliability

If an overbuilt idler wheel is used to ensure durability and robustness, then reliability is improved, but manufacturing costs increase

Engineering Contradiction:

ImprovedurabilityVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The design merges multiple functional requirements into a single integrated structure. The hub portion, rim portion, and reinforcement features are all formed as one piece through injection molding, eliminating the need for separate manufacturing steps, assembly operations, and associated fasteners or joints that would increase manufacturing complexity and cost.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The design utilizes parameter variations in the molding process, including varying wall thicknesses and geometric configurations, to achieve the desired structural integrity and durability. These parameter changes are implemented within the capabilities of injection molding technology, maintaining manufacturing simplicity while achieving overbuilt-level durability.

Inventive Principle:

Principle #35Parameter changes

3Strength

If a forged billet process is used to manufacture the wheel, then strength is improved, but manufacturing complexity and cost increase

Engineering Contradiction:

ImprovestrengthVSAvoidmanufacturing process complexity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The patent replaces the traditional mechanical forging process with an injection molding process. This substitution maintains the ability to produce strong, durable components while significantly reducing manufacturing complexity. The injection molding process can directly form complex three-dimensional geometries including varying wall thicknesses and integrated features that would require multiple forging operations and assembly steps.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The design leverages the unique parameters and capabilities of injection molding technology, including the ability to form complex geometries, control wall thickness precisely, and integrate multiple features in a single process step. These parameter changes enable the manufacturing of strong, durable wheels with reduced complexity compared to forged billet approaches.

Inventive Principle:

Principle #35Parameter changes

4Productivity

If standard idler wheel designs are used for mass production, then productivity is improved, but premature failure occurs due to suboptimal force distribution

Engineering Contradiction:

Improvemass production capabilityVSAvoidservice life

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS20250303788A1Fully cast idler wheel

Publication Date: 2025.10.02 CATERPILLAR INC

AI summary

A fully cast idler wheel may include an annular rim portion, an annular hub portion, and a plurality of beams extending between the annular rim portion and the annular hub portion. The plurality of beams may include a first set of beams and a second set of beams that extend between the annular rim portion and the annular hub portion on opposite axial sides of the fully cast idler wheel. Both the first set of beams and the second set of beams may be offset from each other both axially and circumferentially.