JPS6213803B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ignition coil for an internal combustion engine, and particularly to the structure of a coil cap portion in an iron case type coil.

Conventionally known products have a structure in which a coil cap is fixed to the open end of the case by tightening the wire in order to seal the assembled winding part and core with insulating oil etc. inside the iron case. In order to fix the winding, the tip of the leg of the coil cap extends to insulate the center core of the high voltage section, and this tip bites into the end of the secondary coil. It's summery.

However, the conventional method described above requires a primary spool that serves as the base for the primary coil.
In addition, the tip of the foot of the coil cap bites into the end of the secondary coil to hold down the secondary coil and indirectly fix the primary coil, or the primary spool of the primary coil is held in place by the cap's collar. However, in both cases, play occurs between the cap and the primary coil, and if the ignition coil is installed at a location where it is subject to strong vibrations, the winding section may not be secured properly. Due to the movement of the heavy primary coil, 1.
There is a drawback that the next coil may be disconnected.

In order to solve the above-mentioned drawbacks, the present invention has a shape in which the secondary coil, which is dividedly wound around the secondary bobbin, and the central core are wrapped inside the cylindrical leg of the coil cap so as to insulate the cylindrical leg. The primary coil is wound around the outer circumference of the coil cap, and the shape is such that it can be connected to the primary terminal at the top of the coil cap.
The small cylinder part of the coil cap and the tower part of the secondary bobbin are fitted and connected, and one end of the secondary coil on the cap side is connected to the secondary terminal, and the other end of the secondary coil is connected to the primary terminal. By connecting to the terminal, the primary spool, which is the base of the primary coil, can be eliminated, and the structure is such that the primary coil is wound around a fixed coil cap, so there are no other parts between the winding part and the cap part. Because there is no intervention and no backlash,
Since excellent vibration resistance can be obtained, it is possible to easily and reliably fix the secondary bobbin around which the secondary coil is wound, and further aims to improve the withstand voltage of the secondary high voltage section.

The present invention will be described below with reference to embodiments shown in the drawings. In the first embodiment shown in Figs. 1 to 4, 1 is a cup-shaped iron case, and 2 is fixed to the case 1 by closing the open end of the case 1 by wrapping the open end of the case 1. A coil cap 50 is made of high-voltage insulating resin, and 50 is a secondary bobbin made of high-voltage insulating resin that has a plurality of winding grooves 51 on the outer periphery and a closed part 52 at the lower end, and the closed part 52 is in contact with the inner bottom surface of the case 3. It is placed inside the case 1. A central core 4 is inserted into the secondary bobbin 50 and is insulated at the closed portion 52 of the secondary bobbin 50, and is disposed at the center of the case 1. Reference numeral 5 indicates a secondary coil separately wound in each winding groove 51 of the secondary bobbin 50, 6 a primary coil disposed around the outer periphery of the secondary coil 5, 7 a secondary terminal fixed to the center of the coil cap 2 by integral molding, 8a and 8b are primary coil terminals fixed to the coil cap 2 by integral molding. The end of the winding of the secondary coil 5 pulled out from the bottom side of the case 1 is electrically connected to one of the primary terminals 8b via a sub-wire 11 arranged in the axial direction keeping a sufficient distance from the case 1. The winding start of the secondary coil 5 pulled out from the cap 2 side is electrically connected to the secondary terminal 7 via the sub wire 12 and the plate spring 9. The beginning of the winding of the primary coil 6 is electrically connected to one primary terminal 8b, and the end of the winding of the primary coil 6 is electrically connected to the other primary terminal 8a. Reference numeral 10 denotes a screw for filling the case 1 with insulating oil through a screw hole provided in the secondary terminal 7 and then closing the screw hole.

The structure of the coil cap 2 includes a cylindrical foot 2a that extends toward the bottom of the case 1 and wraps around the secondary coil 5 and the central core 4 in an insulating manner. 2a toward the secondary bobbin 50, and the secondary bobbin 5
A small cylindrical portion 2b that fits onto the outer periphery of the tower portion 53 at the upper end to fix the secondary bobbin 50 within the case 1 is integrally molded. Flange portions 2c and 2d are integrally molded on the outer periphery of the cylindrical foot portion 2a at two upper and lower locations, and a primary coil 6 is wound around the outer periphery of the cylindrical foot portion 2a between the flange portions 2c and 2d. It is designed to do so. Further, a projection (not shown) for winding the end of the primary coil 6 is integrally molded on the upper flange portion 2c, and furthermore, a projection (not shown) for winding the end of the primary coil 6 is integrally molded.
A recess (not shown) extending in the axial direction and having a wide lower end is provided on the inner periphery of the recess. Further, on the outer periphery of the tower portion 53 of the secondary bobbin 50, an axially extending convex portion having a narrow upper end that fits into the recess of the small cylinder portion 2b is integrally molded. Furthermore, primary terminals 8 on the outside of each flange portion 2b, 2d
Fitting grooves 2e and 2f are formed at positions substantially facing b. Then, the insulating tube 13, which has a diameter larger than the groove width of each fitting groove 2e, 5f and covered over the sub-wire 11,
e and 2f, and are fitted and fixed in pressure contact.

Furthermore, winding protrusions 54 and 55 for winding the winding start and winding end of the secondary coil 5 are formed on the upper outer side and the lower outer side of the secondary bobbin 50, and furthermore, the upper end of the secondary bobbin 50 is formed. A notch 56 for passing the sub-wire 12 on the winding start side of the secondary coil 5 is formed in the side, and a storage groove 57 that extends in the axial direction toward the winding protrusion 54 is continuously formed in this notch 56 on the outside. It is formed.

In the above structure, a manufacturing method thereof will be explained.
First, the primary coil 6 is wound around the outer periphery of the cylindrical foot 2a between the flange parts 2c and 2d of the cap 2, and the end of the winding is wound several times around the protrusion of the flange part 2c.
Connect to one primary terminal 8a by soldering.
Further, the beginning of the winding of the primary coil 6 is also connected to the other terminal 8b by soldering. Further, the secondary coil 5 is also wound in advance around the outer periphery of the secondary bobbin 50, and the winding start thereof is wound and fixed around the winding protrusion 54, and the winding start of the secondary coil 5 wound around the winding protrusion 54 is One end of the sub-wire 12 is connected by soldering, and the end of the winding of the secondary coil 5 is wound and fixed around a winding protrusion 55. Then, the central core 4 is inserted into the secondary bobbin 50, and the sub-wire 12 on the secondary coil 5 side is guided through the storage groove 57 and the notch 56 to the upper end of the central core 4. The plate spring 9 is assembled, and the tip portion of the subwire 12 is sandwiched between the plate spring 9 and the center core 4.

Next, after closely fitting the tower portion 53 of the secondary bobbin 50 into the small cylinder portion 2b of the coil cap 2, one end of the sub-wire 11 covered with the insulating tube 13 is soldered to the beginning of the winding of the primary coil 6. The other end of this sub-wire 11 is soldered to the end of the secondary coil 5 wound around the winding protrusion 55. Then, the insulating tube 13 is inserted into each fitting groove 2 provided in each flange portion 2c, 2d by its elastic force.
Fit and fix to e and 2f.

Then, this assembly is stored in the case 1, and the open end of the case 1 is wound and tightened.
The coil cap 2 is fixed to the open end of the case 1 by closing the open end of the coil cap. At this time, the plate spring 9 comes into contact with the inner end of the secondary terminal 7, and the winding start of the secondary coil 5 is electrically connected to the secondary terminal 7 via the sub-wire 12 and the plate spring 9. Moreover, the secondary coil 5 is firmly fixed within the case 1 by the closing portion 52 of the secondary bobbin 50 coming into contact with the inner bottom surface of the case 1 . Thereafter, insulating oil is filled into the case 1 through the screw hole of the secondary terminal 7, and the screw 10 is screwed into the screw hole to seal it.

In the above configuration, the cylindrical leg portion 2a of the coil cap 2 is provided with flange portions 2c and 2d at the top and bottom of its outer circumference, so that the primary coil 6 can be directly wound around the cap 2, and the primary spool can be wound around the cap 2 directly. Obtain an ignition coil with excellent vibration resistance. Moreover, inside the cylindrical leg portion 2a, there are two
A secondary bobbin 50 having a secondary coil 5 wound around the outer periphery is housed therein, and the structure is such that the high voltage section is insulated, thereby improving insulation properties.

Here, a cut window is provided in the cylindrical leg portion 2a, and through this cut window, the winding start side of the secondary coil 5 is connected to the primary terminal 8b, and the winding end side of the secondary coil 5 is connected to the central core 4. , the secondary coil 5
Since the coil cap 2 side of the coil cap 2 becomes the low voltage side, the creepage distance between this low voltage side and the high voltage side (center core 4, plate spring 5, secondary terminal 7) becomes short, and therefore the ignition coil If the high voltage section is exposed from the insulating oil when it is tilted, the withstand voltage will be extremely low.

However, by adopting the structure of this embodiment, the coil cap 2 side of the secondary coil 5 becomes the high voltage side, and there is no need to provide a cut window in the cylindrical foot 2a. The creepage distance between the ignition coil and the voltage section is sufficiently long, and sufficient voltage resistance can be ensured even if the ignition coil is tilted and the high voltage section is exposed from within the insulating oil.

FIG. 5 shows the main part configuration of the second embodiment of the present invention, in which the cylindrical foot 2 is opened before the primary coil 6 is wound.
A sub-wire 11 is arranged on the outer surface of the cylindrical foot 2a, and this sub-wire 11 is fixed in advance to the outer surface of the cylindrical leg part 2a with an adhesive insulating tape 15.
The second coil 6 is wound.

FIG. 6 shows a third embodiment of the present invention, in which a metal plate 16 is embedded in a cylindrical foot 2a, and this metal plate 16 is integrally molded with the cylindrical foot 2a. One end of the plate 16 is made to protrude downward from the lower end of the cylindrical leg portion 2a, and the sub-wire 11 connected to the end of the winding of the secondary coil 5 is wound around this protruding part and connected by soldering, and the other end of the metal plate 16 is is made to protrude in the outer circumferential direction from the cylindrical leg portion 2a above the upper flange 2c, and the winding start portion of the primary coil 5 connected to the primary terminal 8b is wound several times around this protruding portion and soldered. It was designed to connect. According to the second embodiment, the insulating tube 13 is not required in contrast to the first embodiment, and wiring can be simplified.

FIG. 7 shows a fourth embodiment of the present invention. In contrast to the third embodiment, one end of the metal plate 16 is
It is connected and fixed to the next terminal 8b, and this connecting part is also embedded in the cap 2 and integrally molded with this cap 2.

In each of the embodiments described above, the housing groove 57 for passing the sub-wire 12 is provided in the secondary bobbin 5.
Although the sub wire 12 is provided on the outside of the sub wire 12, it may be provided on the inside of the small tube portion 2b. Also, a metal plate can be used instead of the sub wire 12, and this metal plate is a single plate with the plate spring 9. It can also be molded in one piece.

Furthermore, in each of the embodiments described above, the winding of each coil 5, 8 was started on the cap 2 side and the winding was ended on the bottom side of the case 1, but each coil 5, 8 was wound on the cap 2 side and ended on the case 1. Of course, it is also possible to start winding on the bottom side.

Furthermore, in each of the embodiments described above, a concave portion was provided on the inner periphery of the small cylinder portion 2b of the coil cap 2, and a convex portion was provided on the outer periphery of the tower portion 53 of the secondary bobbin 50. A convex portion is provided on the tower portion 5.
A recess may be provided on the outer periphery of 3.

Furthermore, in each of the embodiments described above, the small cylinder portion 2
Although the tower part 53 is fitted to the inner circumference of the tower part 53, the small cylinder part 2b can be fitted to the inner circumference of the tower part 53 by reversing the diameter relationship between the tower part 53 and the small cylinder part 2b. It is also possible to make them fit together.

As described above, in the present invention, the cylindrical leg portion of the coil cap is extended, and the secondary bobbin assembled around the central core and having the secondary coil wound in segments around the outer periphery is housed inside the cylindrical leg portion, and the cylindrical leg portion of the coil cap is extended. Since the configuration allows the primary coil to be wound around the outer circumference of the leg, the coil cap itself serves as the primary spool, which is the base of the primary coil, making it possible to eliminate the primary spool. Since the primary coil is wound directly on the coil cap, there is no play between the cap and the primary coil.
Not only is reliability greatly increased against vibration, but
Since the secondary bobbin around which the secondary coil is wound is wrapped around the cylindrical leg, there is an excellent effect of improving the insulation of the high voltage section.

Furthermore, since the small cylindrical part of the coil cap and the tower part of the secondary bobbin are fitted together, the secondary bobbin on which the secondary coil is wound can be easily and reliably fixed. There is.

Furthermore, one end of the secondary coil on the cap side was connected to the secondary terminal, and the other end of the secondary coil on the bottom side of the case and the primary terminal were electrically connected by a connecting member arranged in the axial direction. from,
The coil cap side of the secondary coil becomes the high voltage side, and the creepage distance between the high voltage side and the low voltage part can be made long enough, which has the excellent effect of ensuring sufficient withstand voltage.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing a first embodiment of the ignition coil of the present invention, FIG. 2 is a perspective view showing the main part configuration of the above ignition coil, and FIGS. 3 and 4 are the main part structure of the above ignition coil. 5th enlarged longitudinal sectional view showing each
FIG. 6 is a front view showing the configuration of main parts of a second embodiment of the ignition coil of the present invention, and FIGS. 6 and 7 are longitudinal sectional views showing third and fourth embodiments of the ignition coil of the present invention. DESCRIPTION OF SYMBOLS 1... Iron case, 2... Coil cap, 2a... Cylindrical foot part, 2b... Small cylinder part, 2c, 2d... Flange part, 2e, 2f... Fitting groove, 4... Central core, 5... 2
Secondary coil, 6...Primary coil, 7...Secondary terminal, 8a, 8b...Primary terminal, 11, 13,
16... Sub wire, insulating tube, metal plate, 50... Secondary bobbin, 51... Winding groove,
52...Closing part, 53...Tower part.

Claims (1)

[Claims] 1. A central core, disposed around the outer periphery of the central core,
A secondary bobbin having a plurality of winding grooves on its outer periphery;
A secondary coil that is divided into windings in the winding groove of the next bobbin, a primary coil that is placed around the outer circumference of this secondary coil, an iron case that houses these, and an insulator that is fixed by closing the open end of this case. coil cap and
The coil cap includes a primary and a secondary terminal fixed to the coil gap, and the coil cap has a cylindrical foot portion extending toward the bottom of the case and wrapping the secondary coil inside, and the cylindrical foot portion. A small cylindrical part extending toward the secondary bobbin and fitting into the tower part of the secondary bobbin is integrally molded on the inside of the cylindrical leg, and the primary coil is wound around the outer periphery of the cylindrical foot part. One end of the secondary coil on the cap side is connected to the secondary terminal, and a connecting member for electrically connecting between the other end of the secondary coil on the bottom side of the case and the primary terminal is axially connected. Ignition coil for internal combustion engine located in. 2. The ignition coil for an internal combustion engine according to claim 1, wherein flange portions are integrally molded on the upper and lower outer periphery of the cylindrical foot portion, and the primary coil is wound between the flange portions. 3. The ignition coil according to claim 2, wherein the connecting member is disposed around the outer periphery of the primary coil and is fitted and fixed in each fitting groove provided in each of the flange parts. 4. The connecting member is disposed on the outer surface of the cylindrical foot on the inner peripheral side of the primary coil,
The ignition coil according to claim 1 or 2, which is fixed to the outer surface of the cylindrical foot. 5. The ignition coil according to claim 1 or 2, wherein the connecting member is embedded in the cylindrical foot and integrally molded with the cylindrical foot. 6. Claim 3, wherein the connecting member includes a sub-wire made of an electrically conductive material and an insulating tube placed over the sub-wire, and the tube is press-fitted into each groove by its elastic force.
Ignition coil as described in section. 7. Claim 5, wherein the connecting member includes a metal plate, and a connecting portion between one end of the metal plate and the primary terminal is embedded in the cap and integrally molded with the cap. Ignition coil as described.