JPH0219940Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an ignition coil bobbin used for winding a high-voltage coil (secondary coil) of an ignition coil used in an ignition device for an internal combustion engine.

[Prior Art] As a bobbin for winding a high-voltage coil of an ignition coil, a large number of flanges are provided at intervals around the outer periphery of a cylindrical body, and grooves for winding the high-voltage coil are formed between the flanges. Things (Unexamined Japanese Patent Publication No. 1983-21614, Utility Model Application No. 1983-
No. 59113) is known. FIG. 4 schematically shows this type of bobbin that has been proposed in the past. In the figure, 1 is a cylindrical body, and 2 is a large number of flanges integrally formed on the outer periphery of the body 1. The coil winding grooves 3, 3, . . . are arranged between the collar portions 2, 2, .
is formed. Coil conductor guide slots 4, 4, . . . are formed in the collar portions 2, 2, . To wind a high-voltage coil around this bobbin, first pass the coil conductor through the coil conductor guide slot 4 of the first flange located at one end of the body (the left end in the example in Figure 4). The coil conductor 6 is guided to the first coil winding groove 3 located at , and the unit coil 5 is wound around the groove. Next, as shown in FIG. 5, the coil conductor 6 is guided into the second coil winding groove 3 through the coil conductor guide slot 4 of the second collar 2, and the coil conductor 6 is guided into the second coil winding groove 3. The second unit coil 5 is wound. Thereafter, unit coils 5 are sequentially wound in each coil winding groove in the same manner, and the final coil winding groove 3 is formed on the other end side of the body 1 (the right end side in the example shown).
After winding the end unit coil,
The coil conductor 6 at the end of the winding of the high-voltage coil is led out to the outside through the coil conductor guide slot 4 of the flange 2 at the end. A low voltage coil 8 wound around an iron core 7 is inserted inside the body 1 of the bobbin around which the high voltage coil is wound, and the entire body is molded with resin to form an ignition coil.

When a high voltage coil is constructed by winding a unit coil with the same number of turns in each coil winding groove of this type of bobbin, the distribution of potential E along the axial direction of the coil is as shown in Figure 8. , the potential gradient becomes high near the starting end La and near the ending end Lb of the high voltage coil L. Therefore, when winding a high-voltage coil on this type of bobbin, the number of turns of the unit coil wound in the coil winding groove 3 located at the end of the bobbin in the axial direction is minimized (usually only one layer is wound). care is taken to reduce the potential gradient at the end of the high-voltage coil.

[Problems to be solved by the invention] When a high voltage coil is wound in parts using a high voltage coil winding bobbin as described above, it is not necessary to insert insulating paper between the layers of the coil, so it is possible to automate the winding work. Therefore, the manufacturing efficiency of the ignition coil can be improved. However, in the conventional bobbin, the depth of all the coil winding grooves is set to be the same, and as shown in FIG. coil and 2
The transition portion 6a that crosses between the coil to be wound in the th coil winding groove portion is the coil conductor guide slot 4.
will be in contact with the bottom of the When the coil conductor is in contact with the bottom of slot 4, the seventh
As shown in the figure, when a high-voltage coil is molded with resin 8, air bubbles 9 may be generated in the resin because the air near the part of the coil conductor 6 that contacts the slot bottom cannot be expelled. There is a possibility that these air bubbles become weak points in the insulation, causing dielectric breakdown.

In addition, in this type of bobbin, each collar 2 is provided with a coil conductor guide slot 4 extending in the tangential direction of the body 1, so the direction in which the bobbin molding die is divided is the direction of the coil conductor guide slot, and the coil conductor guide slot 4 extends in the tangential direction of the body 1. The mating surface of the mold is located near the bottom of each coil conductor guide slot 4. Therefore, burrs are likely to form near the bottom of each coil conductor guide slot, and as shown in FIG. In some cases, it became impossible to wind the eye from a position adjacent to the collar portion 2. In such a state, the coil cannot be wound in an aligned manner in the coil winding groove 3, so the upper layer conductor of the coil in the groove may slip between the lower layer conductors. There was a risk that an interlayer short circuit would occur within the groove. Note that the above problem with burrs can be solved by winding the coil conductor with a large tension, but the coil conductor that makes up the high voltage coil is generally made of extremely thin wire with a wire diameter of about 0.05 mm.
If a large tension is applied, the wire will break.

The purpose of this invention is to eliminate the possibility of bubbles forming in the resin used to mold the high-voltage coil, and also to eliminate the risk of air bubbles forming in the resin used to mold the high-voltage coil. To provide a bobbin for an ignition coil which is prevented from running out.

[Means for solving the problem] The present invention is a coil winding method in which a large number of flanges are arranged in parallel at intervals around the outer periphery of a cylindrical body, and a high voltage coil is wound between the flanges. The above-mentioned problem is solved in an ignition coil bobbin in which a winding groove is formed, and in the present invention, at least one of the plurality of coil winding grooves formed between the collar parts is The depth of the endmost coil winding groove located on the winding start end side is set to be deeper than the depth of the adjacent coil winding groove.

[Operation of the device] With the above structure, the transition portion of the coil conductor from the coil winding groove at the end of the coil winding start end side to the next coil winding groove is obliquely inclined. It becomes a state. Therefore, a gap can be formed between the transition part of the coil conductor and the bottom of the coil conductor guide slot, and when the high voltage coil is molded with resin, it is possible to prevent air bubbles from remaining in the vicinity of the transition part. Can be done. In addition, the transition portion of the coil conductor from the coil wound in the coil winding groove at the end of the winding start side of the high-voltage coil to the next coil winding groove is from the bottom of the coil conductor guide slot where burrs are likely to occur. Since the coil conductor passes through a remote location, the coil conductor can be passed over the crossover portion without being affected by burrs, and the coil can be wound in alignment within the second coil winding groove.

[Embodiments] Examples of the present invention will be described below with reference to the accompanying drawings.

1 and 2 schematically show an embodiment of the present invention, in which 1 is a body, 2 is a number of flanges integrally provided on the body 1, and 3 is a flange. The coil conductor guide slots 4, 4, . . . extending in the tangential direction of the body 1 are alternately formed in the collar portions 2, 2, . . .
They are set 180 degrees apart. In this embodiment, among the coil winding grooves 3, 3, . . . formed between the flanges 2, 2, . The depth of the coil winding grooves 3, 3 at the end portions is set to be deeper than the adjacent coil winding groove by at least the thickness of one coil layer.

With the above configuration, as shown in FIG. The portion 6a crosses diagonally between both unit coils, and a gap S is created between the crossing portion 6a and the bottom portion 4a of the coil conductor guide slot 4. Therefore, when the high-voltage coil is molded with resin, air between the transition portion 6a and the bottom of the coil conductor guide slot 4 can be completely expelled, leaving air bubbles in the resin molding resin and causing weak points in the insulation. can be prevented. Also, crossing section 6
As a result, even if there is a burr near the bottom 4a of the coil conductor guide slot 4, the coil can be passed without being affected by the burr, and the inside of each coil winding groove is The coil can be wound in an aligned manner. Furthermore, since the distance G between adjacent unit coils 5, 5 becomes longer, the insulation distance between adjacent unit coils can be increased, and the insulation strength at the winding start end of the coil can be increased.

In the above embodiment, the coil winding grooves at both ends of the bobbin are deeper than the adjacent coil winding grooves, but only the coil winding grooves at the end of the coil winding start side are used for the adjacent coil winding grooves. It may be made deeper than the circulation groove.

[Effects of the invention] As described above, according to the invention, the depth of the coil winding groove at the end of the coil winding start end is made deeper than the adjacent coil winding groove. , the transition portion of the coil conductor extending from the endmost coil winding groove on the winding start side to the next coil winding groove can be made obliquely inclined, and the transition portion of the coil conductor and the coil conductor can be A gap can be formed between the guide slot and the bottom of the guide slot. Therefore, when a high-voltage coil is molded with resin, it is possible to prevent air bubbles from remaining near the transition portion of the coil conductor on the winding start end side of the coil. In addition, the transition part of the coil conductor from the coil wound in the coil winding groove at the end of the winding start side to the next coil winding groove should be placed away from the bottom of the coil conductor guide slot where burrs are likely to occur. Because it can pass through
The transition portion of the coil conductor can be passed without being affected by burrs, and the coil winding state is disturbed within the second coil winding groove from the end on the winding start side, causing an interlayer short circuit. can be prevented.

[Brief explanation of the drawing]

Fig. 1 is a side view showing an embodiment of the present invention, Fig. 2 is a sectional view taken along the - line in Fig. 1, and Fig. 3 is a coil winding when a high voltage coil is wound around the bobbin of the same embodiment. Fig. 4 is an enlarged longitudinal sectional view of the main part showing the spinning state, Fig. 4 is a longitudinal sectional view showing the conventional example, Fig. 5 is an enlarged longitudinal sectional view of the main part of the conventional example, and Fig. 6 shows the use of the bobbin of Fig. 4. FIG. 7 is an enlarged top view of the main part illustrating problems in the winding state of the coil when the conventional bobbin is used; FIG. FIG. 8 is an explanatory diagram showing an example of the potential distribution along the winding axis direction of the high voltage winding of the ignition coil. 1... Body part, 2... Flam part, 3... Coil winding groove part, 4... Coil conductor guide slot.

Claims (1)

[Scope of utility model registration request] In the ignition coil bobbin, in which a large number of flanges are arranged in parallel at intervals on the outer periphery of a cylindrical body, and a coil winding groove for winding a high voltage coil is formed between the flanges. Among the plurality of coil winding grooves formed between the flanges, at least the endmost coil winding groove located on the winding start end side of the high voltage coil has a depth equal to that of the adjacent coil winding. A bobbin for an ignition coil, characterized in that the depth is set deeper than the depth of the groove.