What Is a Torque Meter?
A torque meter is a device that measures the rotational force applied to a shaft, called torque.
Using the elastic force of a spring or a sensor, it is possible to obtain the force in the direction of rotation as a numerical value. Analog torque meters can display numerical values by themselves, while digital torque meters require a numerical value display and a power supply to operate.
Torque is classified into static torque and dynamic torque, and it is necessary to decide in advance which of the two needs to be measured depending on the purpose of measurement. In recent years, models that can measure both types of torque have become widely used.
Uses of Torque Meters
Torque meters are used to apply a rotational force to a shaft and measure the force in the rotational direction numerically. They are used to measure and control the actual numerical values of the tightening force of screws, the torque to open and close container caps, and the torsional rigidity of shafts, beams, and other structural members.
In recent years, many of them can simultaneously measure not only torque but also strain and shaft rotation speed. Measuring and controlling torque is a very important item to ensure not only proper operation and maintenance of equipment but also safety in the event of life or failure.
Principles of Torque Meters
The simplest principle of torque meters is to rotate torque meters directly connected to a shaft and display the rotational force as a numerical value by the repulsive force of a spring or the like. In recent years, various types of torque meters have become available, including those that use a sensor to measure the strain during rotation as a torsional angle of the shaft to calculate torque, and those that measure torque indirectly as well as directly.
A rotating shaft always has both a motor or other power source to transmit rotation and a turbine or other mechanism to utilize rotation, so a mechanical type torque meter with scale at the end of the shaft requires either mechanism to be removed to use it.
There are also torque meters that are inserted in the middle of the shaft, but the shaft is removed in the same way to install the torque meters. Therefore, mounting and dismounting must be considered when installing torque meters.
Other Information on Torque Meters
1. Motor Testing With a Torque Meters
Torque meters are available in non-rotating strain gauge types, rotating magnetostrictive types, and strain gauge types. The rotary-type torque meters are used for experimental and research purposes and quality control of products. Torque is often heard in the tightening of tire nuts, and the specified torque varies depending on the type of nut.
Torque is also important in motors. Motors are used in many other places besides trains and automobiles, such as pumps, compressors, and elevators.
In motor manufacturing, torque meters are used to confirm that the final torque value is the desired one. Generally, after a motor is manufactured, a load is applied to the motor in a motor testing machine, and measurement is made with sensor-type torque meters.
2. How to Use a Torque Meters
There are two types of torque meters: non-rotating type and rotating type.
Non-Rotating Type
The non-rotating type has a gauge attached to the device to be measured, and the gauge displays the value of the torque applied. Torque wrenches used to check the tightening of car tires are set to the specified torque, and when the torque reaches that value, the wrench makes a sound to confirm that it has been tightened. Since the original torque has been confirmed by calibration equipment, the desired tightening can be achieved simply by setting the torque to the specified value.
Rotary Type
The rotary type is mainly used for torque measurement of motors, and torque meters are installed on the core of the motor via a coupling. In addition to the torque meters, peripheral devices such as a device to receive signals from the equipment and a PC for online confirmation are also required.
The torque meters measure the torsion or distortion of that shaft caused by the torque applied to the shaft, so the motor is rotated and the signal corresponding to the load is converted into a value called torque, which is then measured.