Split Sprocket Track Drive for Outdoor Power Equipment

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Solution Overview

Problem

Current track drives for outdoor power equipment face limitations such as lateral derailment, drive lug skipping, and backlash during load and direction reversals, leading to performance issues and suboptimal conversion of wheeled configurations to tracked configurations, which affect travel speed, center of gravity, and traction system stress.

Innovation Solution

A track drive system featuring a support frame with a centrally located aperture, a drive axle with hub bearings, and split half sprockets that reduce slippage and allow for efficient power transfer, along with idler and bogie wheels for weight distribution, and a track tensioning mechanism to maintain tension on the endless track.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If unitary sprockets are used, then the structure is simpler, but installation and removal become difficult

Engineering Contradiction:
Improvesprocket structureVSAvoidinstallation and removal
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

The sprocket is divided into two half-sprockets that can be assembled around the drive axle separately and then joined together. This segmentation allows each half-sprocket to be independently installed onto the axle from opposite sides, making installation and removal significantly easier while maintaining structural integrity during operation.

Inventive Principle:
Principle #1Segmentation

2Reliability

If conventional track drives are used, then the basic propulsion function is achieved, but lateral derailment and drive lug skipping occur

Engineering Contradiction:
Improvetrack engagementVSAvoidlateral derailment and skipping
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The hub bearing assembly serves as an intermediary component between the drive axle and the half-sprockets. It provides precise alignment and stable mounting for the sprockets, ensuring proper track engagement and eliminating lateral derailment and drive lug skipping by maintaining consistent geometric relationships among all drive components.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Force

If tracked configuration is implemented, then traction performance improves, but center of gravity increases

Engineering Contradiction:
ImprovetractionVSAvoidcenter of gravity
Core Design Contradiction:
ForceVSWeight of moving object

Solution Approach 1:

The drive components are arranged in a compact, space-efficient configuration that utilizes the vertical dimension effectively. The half-sprockets are positioned on either side of the support frame, and the hub bearing is mounted close to the frame, creating a compact drive assembly that minimizes the height and raises the center of gravity less than conventional tracked designs.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 enhances the performance of outdoor power equipment by reducing slippage and stress on the traction system, maintaining travel speed, and evenly distributing weight, thereby improving handling and reducing the risk of track deformation.

Implementation Method 1

a hub bearing mounted on the drive axle and the support frame, the hub bearing enabling the drive axle to rotate relative to the support frame

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3183163B1Track drive
Publication Date: 2019.12.11 MTD PRODUCTS INC
  • EP3183163B1 patent drawingFigure 1
  • EP3183163B1 patent drawingFigure 2
  • EP3183163B1 patent drawingFigure 3A

AI summary

A track drive (24) for outdoor power equipment (20) comprising, a support frame (26); a drive axle (44) configured to attach to an associated drive hub (54) on said outdoor power equipment (20); a hub bearing (64) mounted on said drive axle (44) and said support frame (26), said hub bearing (64) enables said drive axle (44) to rotate relative to said support frame (26); a drive sprocket (66) attached to said drive axle (44), wherein said drive sprocket (66) comprises an interior half sprocket (68) and an exterior half sprocket (70), said half sprockets (68) are located on either side (154) of said support frame (26), wherein said drive sprocket (66) comprises drive teeth (94) spaced radially about said drive sprocket (66); and an endless track (130), wherein said drive sprocket (66) is movably engaged with said endless track (130) to transmit force to rotate said endless track (130) and propel said outdoor power equipment (20).