Tractor Clutch Calibration Using Output Shaft Angular Acceleration
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Solution Overview
Problem
Existing methods for calibrating hydraulically operated clutches in agricultural machines are complex and costly, lacking a precise and cost-effective means to determine torque characteristics within the drivetrain.
Innovation Solution
A method and device that calibrate a selected clutch by determining the relationship between the electrical current of a hydraulic valve and the angular acceleration of the output shaft, using known moment of inertia, to generate clutch-specific calibration data, which includes drag and friction torques, enabling precise torque determination with minimal technical effort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing methods for calibrating hydraulically operated clutches are used, then torque characteristics can be determined, but the calibration process becomes complex and costly
Solution Approach 1:
The patent extracts only the essential measurement elements needed for calibration: a sensor to detect rotational speed of the output shaft. By removing unnecessary complexity from existing calibration methods and retaining only the critical measurement function, the system achieves accurate torque characteristic determination with minimal equipment
Solution Approach 2:
The calibration method utilizes the clutch system's own operational characteristics during normal operation. By measuring rotational speed during engagement and using the known moment of inertia of the output shaft, the system self-calibrates without requiring external calibration equipment or complex procedures
2Measurement precision
If existing calibration methods are implemented, then torque data can be obtained, but the technical effort and cost increase significantly
Solution Approach 1:
The system uses the clutch's own operational dynamics during normal engagement to generate calibration data. The rotational speed sensor captures data during engagement, and the control unit processes this information to determine torque characteristics, eliminating the need for separate calibration procedures or specialized equipment
Solution Approach 2:
The method determines torque characteristics by analyzing changes in rotational speed parameters during clutch engagement. By measuring angular acceleration (the rate of change of rotational speed) and using the known moment of inertia, the system calculates torque without requiring direct torque measurement equipment
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
Enables precise and cost-effective calibration of clutches in agricultural tractors, supporting flexible torque determination and drive management systems with high accuracy and reduced complexity.
Implementation Method 1
The selected clutch can be controlled between a closed state (with complete power transmission) and an open state (with interrupted power transmission)... The clutch is actuated, and the value of a physical quantity that triggers the clutch actuation (e.g., the electrical current of a hydraulic valve acting on the clutch) is determined or set
Implementation Method 2
a physical quantity representing the rotation of the output shaft, namely the angular acceleration according to the invention, is determined. Depending on this rotational quantity of the output shaft—and especially taking into account other physical quantities such as a known moment of inertia of this output shaft—a torque of the selected clutch can be determined
Data Source
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AI summary
The invention relates to a method for calibrating a selected coupling (K1.1) which is arranged within a drive train (20) of an agricultural tractor (10) and can be controlled between a closed and an open state. The selected coupling (K1.1) is connected on the drive side to a running drive motor (22) of the agricultural tractor (10) and on the output side to an output shaft (W1). The value of a physical quantity (l_st_m.n, l_st_1.1) that effects the coupling control is determined. The value of a physical quantity (ω1) representing the rotation of the output shaft (W1) is determined and assigned to the value of the physical quantity (l_st_m.n, l_st_1.1) that effects the coupling control. Depending on this assignment, calibration data (β) for the selected coupling (K1.1) are generated.The invention further relates to a device (50) with a control unit (52) for carrying out such a method. The invention also relates to an agricultural tractor (10) comprising such a device (50).