Torque control of mechanical torque screwdriver: exquisite coordination of structure and mechanics- Hangzhou Hao Gong Tools Co., Ltd.

The core mission of mechanical torque screwdriver is to transmit the rotational force applied by the operator to the handle to the screwdriver head with minimal loss and highest precision, so as to achieve precise tightening of the screw. To achieve this goal, the design of the transmission mechanism needs to seek a perfect balance between force transmission efficiency and structural compactness. The coordinated operation of its internal multi-stage gear set, transmission shaft and bearing constitutes a precise and efficient transmission chain.
In the design of mechanical torque screwdriver, the configuration of the gear set needs to be customized according to the torque output requirements of the actual application scenario. The input force can be amplified step by step by meshing gears with different numbers of teeth and modules. For example, when the handle applies a small rotational force, the torque output by the large gear will increase significantly through the transmission mode of the small gear driving the large gear, thereby meeting the larger torque required for screw tightening. At the same time, the tooth profile design of the gear set is very important. The involute tooth profile has the advantages of stable transmission, strong load-bearing capacity and low wear, making it a common choice for the gear set of mechanical torque screwdrivers. This tooth shape can ensure that the force transmission path is stable during the meshing process of the gears, reduce the energy loss and noise caused by the impact between the teeth, and thus ensure the stability and accuracy of the torque output.
The drive shaft is like the "central nervous system" in the transmission mechanism, responsible for uninterrupted transmission of the torque amplified by the gear set to the screwdriver head. In order to ensure that there is no deformation or distortion during the force transmission process, the drive shaft must have extremely high rigidity. Its material is usually made of high-strength alloy steel, and it undergoes a special heat treatment process to improve the hardness and toughness of the material. The structural design of the drive shaft also needs to be considered comprehensively. The slender shaft body is prone to bending vibration when rotating at high speed, which affects the torque transmission accuracy. Therefore, it is necessary to optimize the shaft diameter and increase the support structure during the design to enhance the vibration resistance of the shaft body. The connection between the drive shaft and the gear and the screwdriver head adopts a high-precision key connection or spline connection to ensure that there is no relative sliding between the components during the torque transmission process, thereby ensuring the integrity and accuracy of the force transmission.
In the transmission chain of the mechanical torque screwdriver, the bearing is mainly used to support the rotational movement of the drive shaft and the gear. Rolling bearings are often used in this type of tools because of their low friction coefficient and high rotation accuracy. The sealing design of the bearing should not be ignored. A good sealing structure can prevent dust, oil and other impurities from entering the bearing, avoiding the increase of friction coefficient and the decrease of rotation accuracy caused by impurity wear. The preload technology of the bearing is also widely used. By applying appropriate preload force to the bearing, the internal clearance of the bearing can be eliminated, the rotation rigidity and stability of the shaft can be improved, and the accuracy of torque transmission can be further guaranteed.
When the operator rotates the handle, the force is first transmitted to the gear set. After being amplified by the multi-stage gears, the torque is transmitted to the screwdriver head through the transmission shaft. In this process, the low friction characteristics of the bearing ensure the smooth rotation and reduce the energy loss during the force transmission process; the precise tooth design of the gear set and the high rigidity structure of the transmission shaft ensure the stability and accuracy of the torque transmission. The performance defects of any component may lead to a decrease in the force transmission efficiency of the entire transmission mechanism and affect the torque control accuracy of the mechanical torque screwdriver.
The transmission mechanism of the mechanical torque screwdriver realizes efficient and accurate force transmission through the precise design and coordinated operation of the multi-stage gear set, transmission shaft and bearing. The design and optimization of each of its components are closely centered around the core goal of improving force transmission efficiency and ensuring torque output stability.