Shaft Torque and Speed Detection Using Helical Actuator
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Solution Overview
Problem
Existing methods for determining torque and speed of rotating machine elements in agricultural machines are costly, require significant installation space, and face challenges in accurate measurement, especially at higher speeds, due to the need for multiple sensors and complex signal transmission.
Innovation Solution
A device that uses a single sensor to detect the axial displacement of an actuator with markings on its peripheral area, allowing for simultaneous determination of torque and speed, utilizing an elastic helix structure to convert torsion into axial displacement and contactless detection principles to avoid friction losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a stationary sensor arrangement measures rotation angle at two axially spaced-apart locations to determine torsion, then torque can be determined, but installation space and cost increase significantly
Solution Approach 1:
The patent combines torque measurement and speed measurement functions into a single sensor arrangement. The sensor detects both the axial displacement of the actuator (which indicates torque) and the rotational position (which indicates speed), eliminating the need for separate sensor systems and reducing overall device complexity
Solution Approach 2:
The sensor system is designed to perform multiple functions simultaneously: it measures both the axial displacement of the actuator for torque determination and the rotational position for speed determination. This multi-functional approach reduces the number of components needed and simplifies the overall measurement system
2Measurement precision
If strain gauges are used to measure torsion, then torque can be determined, but signal transmission becomes complex and error-prone
Solution Approach 1:
The patent replaces strain gauge technology with a magnetic sensor system that detects axial displacement of an actuator. This substitution eliminates the need for complex signal transmission from rotating components, as the sensor can be positioned stationary and detect changes in magnetic field caused by actuator displacement, thereby simplifying the measurement system
3Speed
If a separate speed sensor is used to determine rotational speed, then speed can be measured, but installation space and costs increase
Solution Approach 1:
The patent merges torque measurement and speed measurement into a single sensor system. The same sensor that detects axial displacement of the actuator also detects rotational position through markings on the actuator, allowing both torque and speed to be determined without requiring separate sensor installations
Solution Approach 2:
The sensor system is designed with universal functionality to perform both torque measurement (via axial displacement detection) and speed measurement (via rotational position detection of markings). This multi-functional design eliminates the need for additional speed sensors and reduces overall system complexity
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 compact and cost-effective measurement of torque, speed, and transmitted power with a single sensor, improving accuracy and reducing installation space requirements, particularly effective at lower speeds and in high-speed applications.
Implementation Method 1
An elastic helical structure (with opposite turns) connects the actuator to both shaft ends. Torsion of the shaft caused by a torque transmitted by the shaft leads to a displacement of the central actuator in the axial direction.
Implementation Method 2
By sensory, for example inductive, detection of the displacement of the actuator, the torsion of the shaft and the torque transmitted by the shaft can be determined in this way.
Data Source
Figure 1~2
AI summary
A device (1) for detecting the mechanical state of a machine element rotatable about an axis (3), in particular a shaft (2), comprises an actuator (4) arranged axially movable on the machine element (2), means (9, 10, 11, 12) for converting a torsion of the machine element (2) into an axial displacement of the actuator (4), a sensor (5) arranged at rest relative to the machine element (2) for detecting the axial displacement of the actuator (4), and is characterized in that a marking (6) is assigned to the actuator (4), which can be detected by the sensor (5) for detecting the axial displacement of the actuator (4), wherein a rotational speed (n) of the machine element (2) can be determined from the number of detected markings (6) per unit of time.