Livestock Feed Mixer CVT Torque Control Under Heavy Load

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Solution Overview

Problem

Conventional livestock feed mixers often face power management issues, where the torque demand exceeds the power source's capacity when handling large quantities of feed materials, leading to abrupt mixing cessation.

Innovation Solution

A control system utilizing a continuously variable transmission and an electronic control unit to adjust the speed ratio between the power source and the mixer, ensuring a linear relationship between input and output torque, thereby extending the power source's capacity and preventing overload.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If more feed materials are added to the mixer, then the mixing capacity and productivity are improved, but the torque demand quickly reaches and exceeds the power source limit, causing mixing to stop

Engineering Contradiction:
Improvemixing capacityVSAvoidtorque demand
Core Design Contradiction:
ProductivityVSPower

Solution Approach 1:

The patent implements dynamic speed ratio adjustment through a continuously variable transmission (CVT) system. The electronic control unit continuously monitors torque demand and adjusts the speed ratio in real-time, allowing the system to adapt to changing load conditions as feed materials are added, thereby maintaining continuous operation without exceeding power source limits

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the operational parameters by adjusting the speed ratio between input and output shafts. By modifying this parameter dynamically, the system can deliver appropriate torque levels to match the power source capacity while maintaining productivity, preventing the torque demand from exceeding the power source limit

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the speed ratio is adjusted to extend power source capacity, then the torque control precision is improved, but the device complexity increases due to the continuously variable transmission and electronic control system

Engineering Contradiction:
Improvetorque control precisionVSAvoidtransmission control complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The electronic control unit implements a feedback mechanism by continuously monitoring the torque demand through torque sensors and adjusting the speed ratio accordingly. This closed-loop control ensures precise torque management while automating the complex adjustments, reducing the operational burden despite increased system complexity

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The continuously variable transmission acts as an intermediary between the power source and the mixing mechanism. It provides a buffer that allows smooth torque adjustment, protecting the power source from overload while maintaining the required mixing torque, thus managing the complexity through a dedicated intermediate system

Inventive Principle:
Principle #24Intermediary (Mediator)

3Device complexity

If conventional mixers operate without torque control, then the device complexity is reduced, but the power source is quickly overcome when handling large quantities of feed materials

Engineering Contradiction:
Improvecontrol system complexityVSAvoidcontinuous mixing capability
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The system implements self-service through automated electronic control that monitors torque demand and adjusts the speed ratio without external intervention. The electronic control unit automatically manages the torque control based on real-time conditions, allowing the system to maintain optimal performance independently, thus justifying the added complexity through autonomous operation

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3391741B1Control system for a livestock feed mixer
Publication Date: 2021.09.01 KUHN NORTH AMERICA INC
  • EP3391741B1 patent drawingFigure 1A
  • EP3391741B1 patent drawingFigure 1B
  • EP3391741B1 patent drawingFigure 1C

AI summary

A control system (A-1000) for mixing materials (100) having a container (B-1100) to receive the materials (100), agitators (B-1300), a driveline (B-1200) to drive the agitators at an output speed with an output torque (Tout), an power source (C-1000) to provide an input speed with an input torque (Tin), a continuously variable transmission (A-1500) that connects the driveline and the power source, and an electronic control unit (A-1100) configured to adjust a speed ratio of the continuously variable transmission to provide a linear relationship between the input torque and the output torque with a slope (M), when the input torque is below a control input threshold (Tin_control), and to follow a corrected linear relationship between the input torque and the output torque with a corrected slope (Mc) smaller than the slope when the input torque is above the control input threshold.