What is the principle of torque sensor? In modern industrial production and automation control,

In modern industrial production and automation control, torque sensors play a crucial role. Torque sensors can measure torque and rotational force, and are widely used in various fields such as machinery, automobiles, aerospace, and energy. Understanding the principle of torque sensors helps to better understand their applications and performance characteristics. This article will provide a detailed introduction to the principle, types, and working methods of torque sensors.

The Principle of Torque Sensors

Torque sensors are based on the electrical measurement conversion principle of strain gauges, which converts torque into electrical signals. When an object is subjected to external forces, it will produce strain, causing changes in its size and shape. By measuring this strain, the magnitude of the external force can be determined.

In torque sensors, strain gauges are attached to elastic elements, which undergo deformation when subjected to torque. As a resistance strain gauge, the resistance value of a strain gauge will change with deformation. This resistance change is converted into an electrical signal through a measurement circuit, and ultimately outputs an electrical signal reflecting the magnitude of the torque.

Types of Torque Sensors

1. Resistance Strain Torque Sensor: Uses a resistance strain gauge as a sensitive element; when torque is applied to the sensor, the resistance value of the strain gauge changes, and the resistance change is converted into an electrical signal via a measurement circuit.
2. Inductive Torque Sensor: Utilizes the magnetic resistance effect of magnetic materials; torque is detected by measuring the inductance change of the coil.
3. Fiber Optic Torque Sensor: Uses optical fibers to transmit optical signals; torque is detected by measuring parameters such as the intensity and phase of the optical signal.
4. Piezoelectric Torque Sensor: Uses the piezoelectric effect to convert torque into electrical energy; torque is detected by measuring voltage or charge.

Working Modes of Torque Sensors

1. Direct Measurement: Installing the torque sensor on the drive shaft to directly measure the torque and rotational force of the drive shaft. The advantage of this method is its simple structure, high reliability, and suitability for most mechanical transmission systems.
2. Indirect Measurement: Measuring other physical quantities related to torque, such as speed and angle, and calculating the torque value through a certain conversion relationship. This method requires the addition of other sensors in the system but is suitable for situations where torque sensors cannot be directly installed.

Torque sensors can be classified based on their working principle, measurement method, installation method, etc. Here are some common types of torque sensors:

• Dynamic Torque Sensor: Also known as a torque speed sensor or non-contact torque sensor, primarily used to measure the dynamic torque and speed of rotating objects. It usually consists of induction coils, signal processing circuits, and magnets, and can obtain torque and speed signals by measuring magneto-electric induction.
• Static Torque Sensor: Primarily used to measure static or steady-state torque, such as in door control systems or locking devices. This type of sensor usually consists of an elastic body and a measuring mechanism, which obtains torque values by measuring the deformation of the elastic body.
• Fiber Optic Torque Sensor: Utilizing fiber optic transmission signals, it has the characteristics of high precision, high sensitivity, and strong anti-interference ability. Fiber optic torque sensors can measure small torques down to micro-newton-meters and are widely used in precision measurement and scientific research fields.
• Resistance Strain Type Torque Sensor: Using resistance strain gauges as sensitive elements, converting torque into resistance changes, and obtaining electrical signals through measurement circuits. This type of sensor has a simple structure, high reliability, and is suitable for torque measurement in most mechanical transmission systems.
• Inductive Torque Sensor: Utilizing the magnetoresistance effect of magnetic materials, the torque is detected by measuring the changes in the coil's inductance. This sensor has the characteristics of high precision, low inertia, and fast response speed, and is suitable for high-precision measurement and high-speed applications.
• Hall Effect Torque Sensor: Utilizing the Hall effect principle, torque values are obtained by measuring changes in magnetic field strength. This type of sensor has the characteristics of non-contact, high precision, and high speed, but it needs to be used in conjunction with an external magnetic field generator.
• Piezoelectric Torque Sensor: Using the principle of the piezoelectric effect, torque is converted into electrical energy, and the torque value is obtained by measuring voltage or charge. This type of sensor has the characteristics of high sensitivity and high resolution, but it requires a stable power supply.

In addition to the common types mentioned above, there are other types of torque sensors such as current-type torque sensors and capacitive torque sensors. Different types of torque sensors have different characteristics and application scenarios, and selecting the appropriate sensor type needs to be determined based on actual needs and working conditions.

Conclusion

In summary, torque sensors are based on the principle of electrical measurement conversion using strain gauges, converting torque into electrical signals for measurement. There are various types and working modes of torque sensors to choose from based on different principles and sensitive components. Understanding the principles and characteristics of torque sensors helps to better select and use sensors that are suitable for application needs, improving the efficiency and accuracy of production and automation control. With the continuous development and innovation of technology, it is believed that more high-performance and high-precision torque sensors will emerge in the future, bringing more possibilities for industrial production and automation control.