Transfer Case Chain Jump Prevention via Clutch Disengagement
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Solution Overview
Problem
In four-wheel drive vehicles, the chain in the transfer case often jumps over teeth on the drive and driven sprockets due to brake system imbalances, leading to increased costs and weight modifications that reduce fuel efficiency.
Innovation Solution
A method and system that utilize sensors to detect vehicle parameters and generate chain-jump parameters, triggering the disengagement of a clutch pack in the transfer case to prevent chain jump without modifying the chain, by sending command signals to initiate disengagement when chain-jump thresholds are met.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the chain width, pitch and strength are increased to prevent chain jump, then the chain reliability is improved, but the device weight increases and fuel efficiency deteriorates
Solution Approach 1:
The system performs preliminary detection of chain jump risk using sensors before the actual chain jump occurs. When risk parameters are detected, the clutch pack is proactively disengaged to prevent the chain jump, rather than reacting after the problem occurs. This prevents the need for heavier chain modifications.
Solution Approach 2:
The invention replaces the traditional mechanical solution (modifying the chain structure with increased width, pitch, and strength) with an electronic control system consisting of sensors, a microprocessor, and a clutch pack control mechanism. This substitution eliminates the need for heavier chain components while maintaining chain jump prevention capability.
2Reliability
If the chain width, pitch and strength are increased to prevent chain jump, then the chain reliability is improved, but the manufacturing cost increases
Solution Approach 1:
The invention replaces the expensive mechanical solution (manufacturing heavier and stronger chains with increased width and pitch) with a more cost-effective electronic control system. The sensors, microprocessor, and clutch control mechanism represent a lower-cost approach to achieving the same reliability outcome.
Solution Approach 2:
Instead of changing the physical parameters of the chain (width, pitch, strength), the system changes the operational parameters by dynamically controlling clutch pack engagement based on detected vehicle conditions. This parameter-based control approach avoids the cost of manufacturing modified chains.
3Reliability
If sensors and control systems are added to prevent chain jump, then the chain jump prevention capability is improved, but the device complexity increases
Solution Approach 1:
The microprocessor-based control system serves multiple functions: it detects chain jump risk parameters, processes sensor signals, determines when disengagement is necessary, and controls the clutch pack actuation. This multi-functionality consolidates what could be multiple separate systems into a single integrated unit, reducing overall complexity.
Solution Approach 2:
The clutch pack acts as an intermediary mechanism between the sensor detection system and the chain drive system. Rather than directly modifying the chain or using complex mechanical linkages, the clutch pack provides a simple on/off engagement control that effectively prevents chain jump while maintaining system simplicity.
Data Source
AI summary
A method to prevent chain jump in a drivetrain of a four-wheel drive vehicle including receiving sensed vehicle parameters from sensors in the four-wheel drive vehicle, generating transfer case chain-jump parameters based on the sensed vehicle parameters and sending a command signal to initiate disengagement of a clutch pack in a transfer case of the drivetrain responsive to the generated transfer case chain-jump parameters.