Generally speaking, the structure of the electric screwdriver is composed of a motor, a gear reducer, a clutch device, a screwdriver head and a protective sleeve, a forward and reverse power switch and a power connection device.
The electric screwdriver motor is placed in a plastic housing. The plastic shell is not only the structural part supporting the motor, but also the additional insulation of the stator core.
The additional insulation of the rotor is made of rotating shaft insulation, so that the rotor core is electrically isolated from the exposed metal parts.
The gear box is made of aluminum alloy die casting, one end is connected with the plastic shell by screws through the middle cover; The other end is connected with the outer sleeve of the inner clutch device by a thread. The gearbox is equipped with two pairs of cylindrical helical gears.
The clutch device is composed of a tooth embedded clutch, a pressure spring, an adjusting nut and a spindle with a clamping screwdriver head.
The rotary movement of the screwdriver head is decelerated by the motor through the second gear, and the hollow shaft 4 is driven to rotate. The front end of the hollow shaft is the active part of the tooth embedded clutch. After the motor starts, the hollow shaft rotates without load and the head of the screwdriver is stationary. When the head of the screwdriver is under axial pressure, the hollow shaft spring 1 is compressed, so that the tooth on the end face of the clutch follower 5 engages with the tooth of the clutch active member in the front end of the hollow shaft, so that the spindle 13 rotates unidirectional by the steel ball embedded in the clutch. The spindle is integrated with the spindle pin and the screwdriver head, and the screwdriver head rotates together to tighten or remove the screw.
After engagement of the tooth clutch, the three steel balls in the middle transfer torque. When working, if the required torque is reached or the torque is too large, the toothed clutch follower will compress the spring 8, from the toothed clutch active and driven from the slip, in order to prevent damage to the thread and motor overload.
Adjusting nut 12 Adjusts the output torque of the screwdriver head. By working spring 7, the pressing force of the follower of the tooth embedded clutch is adjusted to ensure the smooth separation of the tooth embedded clutch under a certain torque. The amount of torque can be achieved by turning the adjusting nut. If the adjusting nut to the direction of tooth clutch rotating, spring compression, transfer torque; If the adjustment nut to the tooth clutch in the opposite direction of the rotation, the spring force is small, the transfer torque is small. Screw tightening torque can be adjusted according to the above method to ensure a stable clamping force between the screw and the workpiece, so as to ensure the assembly quality of the screw and the workpiece.
