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Torque meter (what is a torque meter?)
Torque or (Torque): The product of the force applied to an object from the point of effect of the force to the point where the object begins to rotate due to the same force. Torque is the force and energy needed to rotate an object. The engine generates traction or thrust to turn the wheels. For example, when you want to turn a screw with a wrench, the force required to turn the screw is called the torque. In this case, the torque is equal to the amount of force required by the distance from the center of the screw to the place where the force is applied to the wrench.
The units of torque are Newtons per meter, kilograms per centimeter, and feet per pound. The equation of torque is T = R * N, where: T is the torque (TORQUE) and: R is the radius and: N is the applied force, so whenever we want to increase the torque, I either choose a longer wrench or increase the applied force.
Torque is measured by sensing the true deviation of the axis created by a torsional force or by appearing the effects of this deviation. The surface torque of an axis is compressed and stretched. To measure torque, the strain gauges are usually placed in pairs on the shaft. The increase in length is measured by one gauge (in the direction in which the surface is under tension) and the decrease in length is measured by another gauge in the other direction. Primary torque sensors were composed of optimal mechanical structures with strain gauges. Their high cost and low reliability have led to industrial rejection. Although modern technology has reduced the cost of torque sensors, quality control over the product has increased the need for accurate torque measurement.
The torque sensor is a tool for converting, measuring and recording the torque of rotating systems, such as the engine crankshaft or generator shaft, etc. We have two torque models called static torque and dynamic torque. Measuring static torque is relatively easy, but measuring dynamic torque is much more difficult because it requires the transfer of effects such as electricity and magnetism from the measured shaft to a static system.
The sensors used as torque sensors are strain gauges that are mounted on a rotating shaft. Because the sensor needs power and the output signal must be read, dynamic torque measurement becomes more difficult. To do this, circular slip rings were often used in older systems, which are used in newer systems of wireless sensors.
Also, with the help of wireless transmission methods, now even A / D converter and Track Recorder can be placed on the shaft and the measurement accuracy can be greatly increased. Torque measurement with piezoelectric technique is based on SAW and BAW. One of the applications of torque sensor that reduces fuel consumption is in car engine. If you want to know more about SAW effect sensors, you should first read about Rayleigh wave theory or Acoustic Wave Surface theory. For example, insert two combs so that their teeth do not come in contact with each other. In this case, you have created a structure called the Interdigital Transducer (IDT).
Now, if you apply this structure to a piezoelectric substrate with the right materials and apply an AC voltage to both ends at a certain frequency, a surface wave called a SAW will form on the surface of the substrate. If we have another IDT structure on the other side of the substrate, after the surface wave is generated by the first IDT, the two ends of the second IDT generate a voltage whose frequency is approximately equal to the frequency of the input wave in normal conditions where no external mechanical effect enters the substrate. Equal to. However, by applying quantities such as pressure or tension or temperature, etc., below the surface layer, the surface wave frequency of the two output IDT heads will change with the output frequency in the first IDT in proportion to the applied mechanical change (known as mass loading). . The generating frequency in the first IDT is propagated depending on the distance of the comb teeth of its shape from each other, their shape and length in a direction perpendicular to the surface of the teeth in the substrate surface.
But to measure the torque of a shaft with SAW, two SAW resonators are connected in the form of a half-bridge and are fastened on the shaft at right angles to the shaft axis. Now by applying an RF wave (usually 200 MHz) wirelessly to the SAW, on the other hand, depending on the amount of rotation and torque applied from the shaft to the SAW as a load effect, the received wave frequency will change up to one MHz. Accordingly, the measured torque can be up to 1rpm.
Torque sensor sensor configurations
Torque can be measured by rotating strain gauges or magnetoelastic and magnetostrictive sensors, all of which are temperature sensitive. As the torque changes, the magnetic permeability coefficient for the rod changes, which can be measured by a magnetostrictive sensor. , When the rod is unloaded, its permeability coefficient is uniform everywhere. But under torque, the number of magnetic field lines changes in proportion to the torque of the permeability coefficient.
This type of sensor is made up of two primary windings and two secondary windings that are placed on one side of the rod. The magnetoelastic torque sensor measures changes in its permeability by measuring changes in its magnetic field. This type of sensor consists of a thin steel rod that is firmly coupled to the rotating rod. This compound acts as a fixed magnet whose magnetic field strength is proportional to the torque applied to the rod. This narrow bar is placed between the motor and the load. A magnetic sensor converts the generated field into an output electrical signal that alternates with the applied torque.
Torque meter applications
Torque gauges or trackers are used to measure the torque of devices such as engines, gearboxes or even in soda bottles that are part of a rotating system. For example, if the beverage bottle is closed with more than standard torque, it is difficult to open it by hand, so beverage companies must adjust the crack meter or the appropriate torque for twisting in the glass.
The torque meter can also be a torque transmitter or transducer, ie it can be manually and a pointer or with an output. Of course, this measurement is easily done using new technologies and remote models. The information collected on dataloggers for quality control can be accumulated and the results reported. Other industrial applications of torque sensors include measuring chip removal rate, calibrating torque instruments, measuring wear forces, testing springs, and biodynamic measurements.
When buying a torque meter, you should pay attention to the following points:
- Torque and Newton suffering per meter required
- Torque measurement accuracy
- Analog or digital torque meter or crack meter
- Ability to send output signal to torque meter