It can reduce the number of turns of the primary and secondary windings and make the product smaller, and it is easier to obtain high output voltage and large ignition energy, making the ignition of the spark plug more reliable. In the ignition coil failure mode, the most important is high-voltage breakdown, which is mainly caused by poor control of the secondary winding process. At present, the secondary windings for automobiles are all based on groove winding. From the process point of view, the secondary winding process control is the primary condition for determining the quality of ignition coils. In the following, we will make a detailed analysis of several aspects to be noted in the winding. The design and manufacture of the winding mandrel is generally based on the specific design of the skeleton. At present, the most commonly used is a circular skeleton and a rectangular skeleton. For the circular frame, the design of the mandrel is relatively simple, but pay attention to the following points: The diameter of the mandrel that matches with the spindle hole of the winding machine is generally designed according to the matching accuracy of H7/g6, and the mandrel is in line with the winding machine. Three threaded holes shall be uniformly distributed in the circumferential direction of the connected end, and the screws shall be used to prevent the mandrel from rotating circumferentially. The diameter of the mandrel with the skeleton bore must be based on the actual size of the frame, and with the design requirements of the precision. At the same time, it should be considered that the axial position of the frame on the mandrel does not shift due to high speed rotation. The design of the radial circumferential positioning point of the skeleton on the mandrel is preferably a two-way limitation, that is, neither the clockwise direction nor the counterclockwise direction can rotate. If you cannot balance, you must choose the opposite direction of rotation. After the general skeleton is mounted on the mandrel, axial restraint devices that limit the skeleton on the mandrel should be designed as shown in Fig. 1. For a rectangular frame, the design requirements of the winding mandrel are similar to those of the circular frame mandrel, but they also have their own unique features. The excessive arc of the mandrel is slightly larger than the excessive arc of the skeleton as shown in Fig. 2 to facilitate the skeleton installation. After the bobbin is wound, due to the effect of the enameled wire, the rectangular hole must shrink inwards, and it takes a lot of force to withdraw the bobbin from the mandrel. Therefore, when designing the rectangular frame mandrel, it needs to be on the four planes of the mandrel. Each slot is opened and a portion of the mandrel material is removed. The width of the slot depends on the skeleton structure. On the one hand, reducing the contact surface facilitates insertion and extraction of the skeleton; on the other hand, the mass of the mandrel can be reduced, thereby further reducing the moment of inertia. It is best to choose a light and hard aluminum alloy for the material of the mandrel. It not only has a small moment of inertia but also has good dynamic balance. Winding Program Adjustment The so-called winding program is an instruction for the winding machine to perform a set operation. The winding process adopts the winding process, and the key to the winding process is to ensure that the enameled wire accurately transitions in the wire passage. This is also the key to the adjustment of the winding procedure. A single-step procedure is used during the adjustment, that is, it is gradually repeated axis-by-axis. The goal of the adjustment is that there should be sufficient safety margin for the enameled wire to cross the trough, that is, to cross over the edge of the trough when crossing the trough, and the enameled wire must not be in a critical state that seems to pass. When the adjustment is made due to hardware installation or manufacturing reasons, when the individual frames do not meet the requirements, the installation position of the mandrel may be readjusted, or even the mandrel may be replaced. The initial position of the enameled wire passing through the needle is not recommended to be adjusted casually. This puts higher requirements on the adjustment of the winding program. The above are two aspects that should be paid special attention to in the secondary winding. In the actual work, there are defects in the design and manufacturing of the mandrel, as well as the defects in the installation of the mandrel and the adjustment of the winding program, which will appear in the product. One-way partial peaks, bidirectional partial peaks, full-slot overflows, and cross-slot severely affect the winding defects of the ignition coil. The typical defects that often appear in the trench winding process are analyzed one by one in the typical defects that often occur in the trench winding process. Figure 3 shows some common defect cross-sections in the winding process. The first groove is an ideal winding result, and its surface is flat. The ideal state is called because the needle must be adjusted to the edges of the two groove walls. In this position, the critical state is unstable. As a result of the winding, the two sides of the fourth groove in the drawing are high and the middle is low. It is ensured that all of the ideal conditions are achieved. Therefore, it is not recommended to adjust the position of the needle to a critical state during actual operation. 3 Winding Defects Section Diagram The second groove in the diagram is the conventional winding result. It is the best state of the groove winding. The surface is a large arc curve with a radius of about 15 to 20 mm. The needle is adjusted to an appropriate position from the groove wall, generally taking 0. 25mm, and ensuring symmetry until satisfactory. At this time, the enameled wire in the tank is in a stable state. In the figure, the third slot is the middle peak type of one of the defects. The main reason for this kind of winding shape is that the width of the needle line of the needle is adjusted too small, and the enameled wire can only be normally laid in a very small area in the middle. When the side enameled wire can't continue to increase steadily, it will inevitably slip outward and become the peak type with low height on both sides. In the figure, the fourth groove is the middle depression type of the second defect. The reason for this winding shape is that the width of the needle wire of the needle is adjusted to be too large, and the enameled wire is deposited on both sides of the groove wall. When the accumulated enameled wire can not continue to increase steadily, it will inevitably fall inwards and become an intermediate depression with a concave center. The fifth slot in the figure is a unilateral partial peak of the third defect. The reason for this winding shape is that the line width of the needle is generally deviated toward one side, and the enameled wire is insufficiently wound on one side of the slot wall and is in another. The side wall of the groove winding interference, as one side of the high side of the unilateral partial peak type. The sixth slot in the figure is a double sided peak type of the fourth defect. The reason for this winding shape is not caused by the improper adjustment of the line width of the needle, but due to the swing of the mandrel during rotation, so that the enameled wire is deflected to the left on this side, and the shape of the winding is left-biased. Peak; the enameled wire on the other side is skewed to the right, and the shape of the winding is right-handed. In summary, the first three kinds of defects are caused by improper adjustment of the needles, so the best conditions can be achieved by careful adjustment of the winding procedure. The fourth kind of defect has no direct causal relationship with the adjustment of the needle. No obvious change can be made by adjusting the winding procedure. Only by adjusting the installation condition of the mandrel and not causing the mandrel to oscillate, it can make the winding. The best shape 4 . Another important parameter in the control of the winding tension in the winding is to control the tension of the enameled wire, that is, the tension of the enameled wire during winding. The allowable tension of the enameled wire of different diameters is strictly required. If the tension is too small, the enameled wire will loosen, the enameled wire in the groove may overflow due to fluffiness, the tension will exceed the length of the assembly, the length of the enameled wire will become smaller, the diameter will become smaller, the resistance will increase, the paint film will be damaged and the insulation strength will decrease, and the enameled wire can be seriously pulled. Broken. The tension of the enameled wire when the round frame is wound at high speed is a constant that does not change much. The instantaneous linear velocity of the rectangular frame changes periodically, and the pulling force of the enameled wire will be impacted. The inertia of the mechanical spring tensioner cannot keep up with the high frequency change of the winding, and the tension of the enameled wire cannot be reflected in real time. Only one effective value is reflected. . The control of tension is achieved by adjusting the spring tension of the tension brake wheel, and the enameled wire also passes through the clamped felt. The long-term friction of the felt through the enameled wire will wear on the one hand, and the paint film on the enameled wire will also adhere to the felt due to friction. Both of these conditions will change the tension of the enameled wire. Therefore, to clean the felt often, the most practical and practical method in the work site is to change the position of the felt holding the enameled wire. Summary The author gives a detailed analysis of the design and manufacture of the winding mandrel in the secondary winding of the ignition coil, the winding procedure and the typical defects of the winding. At the same time, it also proposes corresponding solutions to some important problems in the secondary winding of automobile ignition coils. It has certain guiding significance in the actual field operation. Elevator Guide Rail,Counterweight Guide Rail,Conveyor Guide Rails,Cold Drawn Guide Rail Jiefeng Elevator & Escalator Co., Ltd. , http://www.jyelevatorparts.com