Transmission Directional Shift Control for Mobile Machines
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Solution Overview
Problem
Existing transmission systems in mobile machines like haul trucks and loaders experience excessive wear during directional shifts due to momentum dissipation and frictional losses, leading to reduced component lifespan.
Innovation Solution
A control system that detects requests for directional shifts, overrides them if the ground speed is above a threshold, limits the power source output speed, and uses the brake unit to reduce speed before executing the shift, ensuring the transmission can change directions without straining the powertrain components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a directional shift is attempted while the machine is in motion, then the transmission can change direction quickly, but momentum dissipation causes excessive wear on transmission and powertrain components
Solution Approach 1:
The control system detects a directional shift request and determines ground speed before the shift is executed. If the ground speed exceeds a threshold, the system overrides the request or prepares the machine by limiting power source output speed and applying brake force to reduce ground speed below the threshold. This preliminary speed verification and reduction prevents high-speed directional shifts that would cause excessive momentum dissipation and component wear.
2Adaptability or versatility
If the transmission shifts between multiple speeds to allow different travel speeds, then the machine can adapt to varying operational requirements, but the complexity of the transmission system increases
Solution Approach 1:
The control system continuously monitors ground speed and compares it against a threshold value. Based on this feedback, the system dynamically adjusts its response to directional shift requests—either overriding them, preparing the machine through speed limitation and braking, or allowing the shift to proceed. This feedback mechanism enables the transmission system to manage complexity through intelligent control rather than mechanical complexity.
3Speed
If a clutch is engaged to attain the second direction while momentum is high, then the transmission can switch directions, but the clutch slips and friction material wears away
Solution Approach 1:
Before engaging the clutch for directional switching, the control system performs preliminary checks to ensure ground speed is below the threshold. If the speed is too high, the system first limits the power source output speed and applies brake force to reduce ground speed. This preliminary speed reduction ensures that when the clutch is subsequently engaged, the momentum difference is minimal, preventing clutch slip and friction material wear.
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
This method allows for smooth directional shifts with reduced wear on powertrain components, minimizing momentum dissipation and extending their lifespan.
Implementation Method 1
a brake unit to apply braking force against the traction devices to retard machine motion
Data Source
AI summary
A method for shifting a transmission in a machine. The method includes detecting a request for a directional shift of the transmission and determining a ground speed of the machine in response to the request. The method further includes overriding the request if the ground speed is above a ground speed threshold. Further, the method includes preparing the machine for the directional shift by limiting an output speed of a power source of the machine and by issuing a command to a brake unit of the machine to reduce the ground speed of the machine. Furthermore, the method includes validating and raising the request to the transmission to execute the directional shift if the ground speed is below the ground speed threshold.