Tooth Jump Protection for Chain Slack and Higher Jump Torque

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Solution Overview

Problem

Chain slack buildup in conventional chain systems leads to reduced jump torque performance, as chain jumps can occur on either the driven or drive sprocket, affecting the efficiency and reliability of the chain system.

Innovation Solution

A tooth jump protection device (TJPD) is employed to control chain slack, ensuring it builds only on the drive sprocket, thereby increasing jump torque performance and allowing for reduced chain width.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If chain slack is allowed to accumulate freely in the chain system, then the chain system operates with simpler structure and lower manufacturing cost, but chain jumps occur on either driven or drive sprocket resulting in reduced jump torque performance

Engineering Contradiction:

Improvejump torque performanceVSAvoidchain system structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

A tooth jump protection device is introduced as an intermediary component between the chain and sprockets. This device selectively allows slack accumulation on the drive sprocket while preventing it on the driven sprocket, thereby mediating the interaction between chain slack and sprocket engagement to ensure jumps occur only on the drive sprocket where they produce higher torque

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The harmful effect of random slack accumulation is extracted and isolated to specific locations. By removing the freedom of slack movement and constraining it to occur only on the drive sprocket, the system eliminates the harmful variability of jump locations while maintaining overall system functionality

Inventive Principle:

Principle #2Taking out (Extraction)

2Force

If chain slack accumulation is controlled to occur only on the drive sprocket, then jump torque performance increases, but the device complexity increases due to additional protection mechanisms

Engineering Contradiction:

Improvejump torqueVSAvoidprotection device structure

Core Design Contradiction:

ForceVSDevice complexity

Solution Approach 1:

The protection device applies different constraints to different locations in the chain system. Specifically, it allows slack accumulation on the drive sprocket side while preventing it on the driven sprocket side, creating local differences in slack management to optimize jump torque without requiring complete slack elimination throughout the entire system

Inventive Principle:

Principle #3Local quality

3Ease of manufacture

If the chain system is designed without slack control mechanisms, then manufacturing and installation are simpler, but chain jumps reduce system reliability and performance

Engineering Contradiction:

Improvechain system assemblyVSAvoidchain jump control

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The tooth jump protection device is pre-installed in the chain system to establish predetermined slack accumulation zones before operation. This preliminary configuration ensures that during normal operation, slack will naturally accumulate in the correct location (on the drive sprocket) without requiring active control or complex adjustment mechanisms during operation

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS12320425B2Tooth jump protection device

Publication Date: 2025.06.03 BORGWARNER INC

AI summary

A tooth jump protection device is used to control chain slack and delay the torque at which chain jump occurs, thus increasing jump torque performance. The tooth jump protection device is preferably mounted to the transfer case.