Torque sensor itself appeared in a short period of time should be used in various industries, become indispensable varieties of the sensor series.
First, the characteristics of the torque sensor:
1、 can measure both static torque and rotating torque, both static torque and dynamic torque.
2、 high detection accuracy, good stability; prevent interference;
3、Small size, light weight, diverse mounting structure, easy to install and use. No need to repeat 0, can continuously measure positive and negative torque.
4、No wear parts such as conduction ring, can run for a long time at high speed.
5、 the sensor output high-level frequency signal can be sent directly to the computer processing.
6、measuring elastomer strength can withstand high overload.
Second, the torque sensor measurement principle:
Specialized torsion strain gauge as a strain adhesive attached to the measurement of the elastic shaft, constituting a strain bridge, the power supply for the strain bridge, you can measure the elastic shaft torsion of the electrical signal. After amplifying this deformation signal, it undergoes pressure/frequency conversion into a frequency signal that is proportional to the torsional response. The system's energy input and signal output by two sets of special toroidal transformers with a gap is responsible for, and therefore provide contactless energy and signal transmission function.
Third, the principle structure of the torque sensor:
A special torque measuring piece is pasted on a special elastic shaft to form the basic torque sensor - variable bridge. Fixed on the shaft: (1) the secondary coil of the energy toroidal transformer, (2) the primary coil of the signal toroidal transformer, (3) the shaft printed circuits, circuit boards including rectifier stabilized power supply, instrumentation amplification circuits, V/F conversion circuits and signal output circuits.
Fourth, the torque sensor work process:
To provide 15V power supply for the sensor, the crystal oscillator on the magnetic circuit generates a square wave of 400Hz, which generates an AC magnetic power supply through the TDA2030 power amplifier. It is transmitted from the stationary primary coil to the rotating secondary coil through the energy toroidal transformer T1. The resultant AC power supply is passed through a rectifier-filter circuit on the shaft to obtain a 5V DC power supply. This supply is used as the operating power supply for the operational amplifier AD822. A high-precision power supply consisting of a reference power supply AD589 and a dual op-amp AD822 produces a 4.5V DC power supply. This power supply is used as the operating power supply for the bridge power supply, amplifiers and V/F converters.
When the elastic shaft is twisted, the mV level deformation signal detected on the deformation bridge is amplified to a strong 1.5v 1v signal by the instrumentation amplifier AD620 and then converted to a frequency signal by the V/F converter LM131. Through the signal ring transformer T2, this can be passed from the rotating primary coil to the static secondary coil, and then filtered and shaped by the signal processing circuitry in the sensor housing to obtain a frequency signal proportional to the torque received by the elastic bearing, which is zero between the static rings due to the fact that this rotary transformer is in motion. Only a few millimeters of clearance, the sensor shaft partially sealed in the metal housing, forming an effective shielding, and therefore has a strong anti-interference ability.
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