An electric torque wrench is a high-precision wrench that can be set with torque powered by a power source. It is a tool for tightening and removing bolts.
Torsion-shear type is specially used for twisting torsion-shear type bolts, and electric wrenches are selected according to the bolt specifications; high-precision fixed torque is mainly used in occasions where torque is required, and electric wrenches are selected according to the torque size; impact type electric wrenches are cheap and efficient, but torque accuracy Poor, choose the electric wrench mainly according to the bolt specifications.
As the precision of work increases, the demand for torque wrenches in all walks of life is also increasing. So, what should be paid attention to in the selection of torque wrenches?
First, look at the motor
Current electric motors are divided into brushed and brushless.
What is a carbon brush?
The inside of the brushed motor is on the surface of the commutator. When the motor is rotating, the electric energy is sent to the coil through the commutator. Because its main component is carbon, called carbon brush, it is easy to wear. Should be regularly maintained and replaced, and clean up carbon deposits.
How does a brushless motor work?
The brushless motor adopts electronic commutation, the coil does not move, and the magnetic pole rotates. The brushless motor uses a set of electronic equipment to sense the position of the magnetic pole of the permanent magnet through the Hall element. Based on this perception, an electronic circuit is used to switch the direction of the current in the coil in time to ensure that the correct direction of magnetic force is generated to drive the motor . Eliminate the disadvantages of brush motors.
Although the price of the brushless motor is slightly more expensive, it has a relatively low failure rate, long life, and relatively high cost performance.
Second, look at torque
Generally, the highest torque of domestic torque wrenches can reach about 10,000 Nm, while the highest torque of German electric wrenches can reach 40,000 Nm. According to the bolt size and process requirements, select the appropriate torque range.
Bolt torque value
Bolt torque value
Third, look at the speed
The speed directly determines the working efficiency, and the fast speed wrench can save the operator valuable working time.
Fourth, look at accuracy
High-precision wrenches will stop rotating accurately when the preset torque is reached. Especially for flange bolts that require high tightening accuracy, it is recommended to use high-precision wrenches to effectively prevent leakage. The general accuracy of the German electric wrench is plus or minus 3%, which is currently the highest precision wrench in the world.