Nut Runner Torque Sensor Placement for Precision Control
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Solution Overview
Problem
Nut runners often fail to accurately reach the specified setpoint torque during nut tightening due to indirect torque measurement methods, resulting in a significant difference between the actual and desired torque values.
Innovation Solution
Incorporating a torque sensor between the motor and the tool holder allows for direct measurement of the generated torque, enabling the control device to switch off the motor at the actual measured torque, thereby reducing inaccuracies and improving the precision of reaching the setpoint torque. Additionally, a planetary transmission can be used to accommodate the torque sensor in a space-saving manner, and wireless data transmission can simplify the assembly and operation of the nut runner.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If indirect torque measurement method is used, then the device complexity is reduced, but the measurement precision deteriorates
Solution Approach 1:
A torque sensor is introduced as an intermediary component between the motor and the tool holder to directly measure the torque generated by the motor. This mediator provides accurate torque measurement data to the control device, enabling precise control of the tightening process while maintaining a relatively simple overall device structure.
2Measurement precision
If torque sensor is arranged close to the tool holder, then the measurement precision is improved, but the device complexity increases
Solution Approach 1:
The torque sensor is merged with the planetary transmission components, specifically integrated into the structure of the planetary gear system. This combining of functions allows the torque sensor to be positioned close to the tool holder for accurate measurement while utilizing the existing transmission structure to avoid adding separate complex mounting arrangements.
3Power
If planetary transmission is used, then the power transmission capability is improved, but the device complexity increases
Solution Approach 1:
The planetary transmission serves multiple functions: it provides the necessary torque multiplication for large screw connections, acts as a structural framework for mounting the torque sensor, and contributes to the overall compact design of the nut runner. This multi-functionality justifies the increased complexity by delivering superior power transmission capability.
Data Source
AI summary
In a nut runner with a motor (3) for generating a torque, a tool holder (9) which is operatively connected with the motor (3) and transmits the generated torque to a tool, a measuring device (7) which continuously measures at least one measurement quantity for determining the torque and forwards the measurement value, and a control device (12) which is connected with the motor (3) and the measuring device (7) and controls the operation of the motor (3) such that after starting it generates a continuously increasing torque, and which shuts off the motor upon reaching a setpoint measurement value, the measuring device is a torque sensor (7) and the torque sensor (7) is arranged between the motor (3) and the tool holder (9).