Analysis of winding tension of loop winding machine
Analysis of winding tension of loop winding machine
Toroidal winding machine-Toroidal coil winding machine-Enameled wire is wound radially on the closed toroidal structure (for details, please refer to the toroidal winding machine tutorial): With the rapid development of the domestic power industry, the demand for current transformer coils Increasingly, the development of current transformer coil winding equipment is imminent. In order to meet the needs of the market, we have developed a current transformer toroidal coil winding machine based on imported equipment. During the design and testing process, we found that, The key to the design of toroidal winding machine is the control of winding tension.
This automatic winding machine is composed of a frame, a pay-off mechanism, a winding head, a tape head, a clamping device, and a control system.
loop winding machine, automatic winding machine,
1, the working principle of toroidal winding machine
Firstly, the wires are evenly wound on the wire storage ring, and then the wires wound on the wire storage ring are wound on the skeleton by a shuttle. The skeleton is driven by the servo motor to rotate, so that the wires are evenly arranged on the skeleton when the wire is wound to a certain amount , And then wind the tape on the frame through the wire storage ring, and then wind it.
2, analysis of winding tension
Through our continuous practice, we have discovered that during the entire winding process, using appropriate force to wind the wire tightly on the skeleton is the key to the quality of the winding. Therefore, we will focus on the factors that affect the winding tension.
1. The grinding moment of the rotating part of the thread bobbin
2. The moment of inertia caused by the acceleration of the thread bobbin part (including the wire wrapped in the bobbin).
The main part of the frictional torque is generated by the tension mechanism, which prevents the wire shuttle from moving and tightens the wire to generate winding tension.
Due to the influence of the winding ring surface and its deviation from the center position in the winding gear, even if the winding is at a constant speed, the movement speed of the thread shuttle is small and uniform, which generates the moment of inertia caused by acceleration, which affects the winding tension.
The movement speed of the thread shuttle can be regarded as composed of two speeds: one is the speed Vo equal to the speed of the pulley on the winding gear, and the other is the speed at which the thread shuttle releases the amount of wire. The former is a constant, and the latter is calculated as follows ( see picture 1)
loop winding machine winding tension analysis 1
So in order to reduce the acceleration of the thread bobbin, it is required:
1. The frame profile H should be small, and the profile should be as close as possible to the center of the winding gear, that is, the value of 1 should be small.
2. The thread hook flat diameter R should be as small as possible.
3. The winding speed ω cannot be too high (this is in conflict with improving production efficiency).
The approximate curve of the speed Vx and acceleration а of the mountain thread shuttle is obtained by the graphical method, and the description is as follows (see Figure 2 and Figure 3):
loop winding machine winding tension analysis 2
1. When the small pulley on the winding gear is at the 0° position, the speed of the thread shuttle is equal to the speed of the small pulley V0, when the speed of the thread shuttle gradually increases from 0-60°, there is a positive acceleration at this time. =600-180`) when the thread shuttle moves at a constant speed, the speed is Vm>Vo. When а=180°~263°, the speed of the thread shuttle gradually decreases. At this time, there is a negative acceleration a = 263°. The speed of the thread shuttle is equal to the pulley speed V. When а=263°~345°, the speed of the thread shuttle continues to decrease. Small, that is, it is lower than V and has a negative acceleration. When а=345°, the speed of the thread shuttle is the minimum Vo, when а=345°~360°, the speed of the thread shuttle increases gradually and there is a positive acceleration.
2. When the winding gear rotates at a constant speed, the speed of the thread shuttle will be zero if it is small, so the friction tension mechanism always acts as a brake to keep the wire tensioned.
3. If Vp is the average linear velocity of the thread bobbin; Vo is the linear velocity of the pulley on the winding gear; L is the perimeter of the wire of the potentiometer, then
4. When the winding speed ω is not large: the wire bobbin diameter R is small, and the potentiometer profile size H is also small. When the profile is as close as possible to the center of the winding gear, the acceleration change is small and large, and the inertia caused by the acceleration The torque is much smaller