JPH11186078A - Ignition coil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize both assembly accuracy and assembly workability, when high tension terminals at a secondary wiring side and a high tension tower part side of an ignition coil are connected. SOLUTION: A terminal holding part 25 is formed integrally in the lower end of a secondary side spool 21, and an approximately U-shape bent wiring side high tension terminal 26 is force-fitted in a mounting hole 28 formed sideways in the terminal holding part 25. A tower side high tension terminal 29 is provided to project upward to a high tension tower part connected to an ignition plug, and three positioning projection parts 32, 33, for example, for positioning the tower side high tension terminal 29 are formed at almost regular intervals in an inner circumferential part of a terminal insertion hole 31 formed in a central part of the terminal holding part 25. A lower part of each of position projection parts 32, 33 is formed to a tilting surface which is tilted diagonally upward towards an inner circumferential side, so that the toward side high tension terminal 29 can be inserted readily. The positioning projection parts 32, 33 function to align a lower end part of the secondary side spool 21.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ignition coil having an improved structure of a high voltage terminal connecting portion between a secondary winding and a high voltage tower.

[0002]

2. Description of the Related Art For example, in a so-called stick type ignition coil which is mounted in a plug hole of each cylinder of an engine, a primary winding and a secondary winding wound on two spools having different diameters are formed in a rod shape. It is housed concentrically in a cylindrical coil case together with the central core, and a high-pressure tower connected to a spark plug is attached to the lower end of this coil case by bonding or the like, and epoxy-based heat is applied from the upper end opening of the coil case. It has a structure filled with a filler such as a curable resin. In this device, as shown in FIG. 6, in order to reduce the manufacturing cost of the secondary winding side high voltage terminal (hereinafter referred to as “winding side high voltage terminal”), as shown in FIG.
Is formed by bending a copper wire or the like into a U-shape, and this winding-side high-voltage terminal 1 is press-fitted laterally into a terminal holding portion 2 integrally formed at the lower end of a spool 5 on the secondary winding side. And a pin-shaped tower-side high-voltage terminal 3 projecting upward from a high-voltage tower section (not shown).
To connect from below. The terminal holding portion 2 has a circular terminal insertion hole 4 for inserting the tower-side high-voltage terminal 3 from below.

[0003]

FIG. 6 (b)
As shown in (2), when the tower-side high-voltage terminal 3 is sandwiched between the U-shaped winding-side high-voltage terminals 1, both sides of the tower-side high-voltage terminal 3 are expanded to some extent so that the contact pressure therebetween is sufficiently ensured. It is set to be in a state where it was done. In this state, a force for pushing the tower-side high-voltage terminal 3 toward the opening side of the winding-side high-voltage terminal 1 indicated by an arrow A acts due to the springback force of both sides of the winding-side high-voltage terminal 1. When assembling, when inserting the tower side high voltage terminal 3 into the winding side high voltage terminal 1,
Since the filler is not yet filled in the coil case and the position of the lower end portion (terminal holding portion 2) of the spool 5 of the secondary winding is not fixed, the arrow A acting on the tower side high voltage terminal 3
The lower end of the spool 5 of the secondary winding shifts in the direction opposite to the arrow A and is eccentric due to the reaction of the force in the directional direction. As a result, the concentric accuracy between the components in the coil case decreases, and The insulation distance between the parts varies, and the insulation is reduced.

In this case, the maximum displacement of the spool 5 of the secondary winding is determined by the size of the clearance B between the terminal insertion hole 4 of the terminal holding portion 2 and the tower-side high-voltage terminal 3. Then, the amount of displacement of the spool 5 can be reduced. However, if the clearance of the terminal insertion hole 4 is reduced, it becomes difficult to insert the tower-side high-voltage terminal 3 into the terminal insertion hole 4, and the assembling workability is reduced. Therefore, in the above-described conventional high-voltage terminal connection structure, it is difficult to achieve both assembly accuracy (insulation) and assembly workability.

The present invention has been made in view of such circumstances, and accordingly, it is an object of the present invention to provide an assembling precision and an assembling work for connecting a high voltage terminal of a secondary winding to a high voltage terminal of a high voltage tower. It is an object of the present invention to provide an ignition coil capable of achieving both characteristics.

[0006]

In order to achieve the above object, in the ignition coil according to the first aspect of the present invention, the winding-side high-voltage terminal is formed by bending a linear conductor into a substantially U-shape or a substantially V-shape. A terminal insertion hole into which a tower side high voltage terminal is inserted is formed in a terminal holding portion provided at a lower end of a spool of the secondary winding, and the tower insertion hole is formed in an inner peripheral portion of the terminal insertion hole. A positioning projection for positioning the side high-voltage terminal is formed. In this case, the positioning projection may be pressed or contacted with the tower-side high-voltage terminal inserted into the terminal insertion hole, or may be merely brought close to it. In any case, due to the positioning effect of the positioning projections, the positional accuracy between the terminal insertion hole of the terminal holding portion and the tower-side high-voltage terminal can be improved as compared with the related art, and thus, the tower-side high-voltage terminal , The lower end portion (terminal holding portion) of the spool of the secondary winding can be accurately positioned. That is, in the present invention, the positioning convex portion plays a role of centering the lower end portion of the spool of the secondary winding, so that the concentric accuracy between the components in the coil case can be improved, and the insulating property can be improved.

If the clearance is reduced by reducing the inner diameter of the terminal insertion hole in order to increase the concentric accuracy, it becomes difficult to insert the tower-side high-voltage terminal into the terminal insertion hole, and the assembling workability is reduced. However, in the present invention, since the concentric accuracy is improved by the positioning projection, it is not necessary to reduce the inner diameter of the terminal insertion hole. Furthermore, when the tower side high voltage terminal is inserted into the terminal insertion hole, even if the tower side high voltage terminal comes into contact or pressure contact with the positioning projection, the contact / pressure contact area is small. Is not so large, and the tower side high voltage terminal can be relatively easily inserted into the terminal insertion hole. Generally, the terminal holding portion and the positioning protrusion are formed of insulating resin together with the spool, and when the tower-side high-voltage terminal is pressed against the positioning protrusion, the positioning protrusion is deformed accordingly. The contact and press-contact resistance force is small, and the assembling workability is good.

In this case, it is preferable that the positioning projection is formed at a portion of the inner peripheral portion of the terminal insertion hole located at least on the opening side of the winding-side high voltage terminal. In other words, the spring-back force on both sides of the winding-side high-voltage terminal exerts a force that pushes the tower-side high-voltage terminal toward the opening of the winding-side high-voltage terminal. In this case, the displacement of the tower-side high-voltage terminal due to the springback force of the winding-side high-voltage terminal can be effectively prevented by the positioning projection.

It is preferable that the positioning projections are formed in at least three places on the inner peripheral portion of the terminal insertion hole. With this configuration, the tower-side high-voltage terminal can be accurately positioned at the center of the terminal insertion hole.

Further, it is preferable that the lower part of the positioning protrusion is formed on an inclined surface which is inclined obliquely upward toward the inner peripheral side. In this way, when the tower-side high-voltage terminal is inserted into the terminal insertion hole, the lower inclined surface of the positioning projection serves as a guide surface for guiding the insertion of the tower-side high-voltage terminal. Performance can be improved.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a stick type ignition coil will be described below with reference to FIGS. First, the configuration of the entire ignition coil 10 will be described with reference to FIG. The cylindrical coil case 11 is formed of an insulating resin, and a connector housing 14 in which a connector pin 13 is insert-molded is assembled into a head case 12 integrally formed on an upper end thereof by press fitting or the like. An igniter 16 is mounted on a pedestal 15 integrally formed with the connector housing 14, and an ignition signal output from an engine control computer (not shown) is input to the igniter 16 via a connector pin 13.

Inside the coil case 11, a rod-shaped center core 18 and a cylindrical outer core 19 are accommodated concentrically at the center and the outer periphery, respectively. Cylindrical outer core 19
A primary winding 20 wound around a primary spool (not shown) made of an insulating resin is housed on the inner peripheral side of the first winding. Further, an inner peripheral side of the primary winding 20 is made of an insulating resin made of an insulating resin. The secondary winding 22 wound around the secondary spool 21 is housed. The center core 18 is housed inside the secondary spool 21,
A cushion member 23 made of a heat-resistant elastic material such as an anti-magnetostriction sponge or an elastomer is applied to the upper and lower ends of the center core 18, respectively. Inside the coil case 11 and the head case 12, as a filler 30,
An insulating resin such as an epoxy-based thermosetting resin is vacuum-filled.

The lower end of the pedestal 15 of the connector housing 14 is fitted with a positioning cylinder 35 for positioning the upper end of the secondary spool 21 by fitting, and the upper end of a spool (not shown) of the primary winding 20. A positioning cylinder portion 36 for positioning is formed integrally with each other. Secondary spool 2
1 is fitted into an annular gap between the positioning cylinder portions 35 and 36, and an elastic engaging claw 37 integrally formed on the upper end portion of the secondary spool 21 toward the outer peripheral side is provided on the outer peripheral side. The secondary spool 21 is engaged with the pedestal 15 of the connector housing 14 by being engaged with the step portion of the positioning cylinder portion 36. The upper end of the center core 18 is fitted on the inner peripheral side of the positioning cylinder 35, whereby the upper end of the center core 18 is positioned.

On the other hand, a terminal holding portion 25 is integrally formed at the lower end of the secondary spool 21, and the terminal holding portion 25 has a winding-side high-voltage terminal 2 connected to one end of the secondary winding 22.
6 are assembled. The winding side high voltage terminal 26 is
As shown in FIG. 5 to FIG. 5, a wire conductor such as a copper wire is formed by bending into a substantially U-shape.
A connecting portion 27 connected to one end of the secondary winding 22 is formed at one end of the secondary winding 22. The winding-side high-voltage terminal 26 is press-fitted from a lateral direction into a mounting hole 28 (see FIGS. 2 and 3) formed laterally in the terminal holding portion 25 and fixed.

In the center of the terminal holding portion 25, a circular terminal insertion hole 31 for inserting a tower side high voltage terminal 29 described below from below is formed upward. A tapered surface 34 for guiding the insertion of the tower-side high-voltage terminal 29 is formed on the peripheral edge. For example, three positioning projections 32 and 33 for positioning the tower-side high-voltage terminal 29 are provided on the inner peripheral portion of the terminal insertion hole 31.
Are formed at substantially equal intervals above the winding side high voltage terminal 26. Among them, two positioning projections 32 are formed on the opening side (the right side in the drawing) of the winding-side high-voltage terminal 26, and the remaining 1
The positioning protrusions 33 are formed on the bottom side (left side in the drawing) of the winding-side high voltage terminal 26. The lower portion of each of the positioning projections 32 and 33 is formed as an inclined surface that is inclined obliquely upward toward the inner peripheral side, and this inclined surface serves as a guide surface for guiding the insertion of the tower-side high-voltage terminal 29. In this case, the positioning projections 32 and 33 may be pressed into contact with or contact with the tower-side high-voltage terminal 29 inserted into the terminal insertion hole 31 or may be brought into close proximity.

On the other hand, as shown in FIG.
A high-pressure tower 38 made of an insulating resin is attached to the lower end of 1 by bonding or the like. At the upper center of the high-voltage tower section 38, a terminal cup 39 in which a pin-shaped tower-side high-voltage terminal 29 is fixed upward is insert-molded. It is kept in the electrically conductive state. When the high-pressure tower 38 is inserted into a plug hole (not shown) and press-fitted into the upper portion of a spark plug (not shown), a conductive spring 40 locked in a terminal cup 39 causes a terminal of the spark plug to be connected. , Whereby one end of the secondary winding 22 was electrically connected to the terminal of the ignition plug via the winding side high voltage terminal 26, the tower side high voltage terminal 29, the terminal cup 39, and the spring 40. State.

When assembling the ignition coil 10 configured as described above, the secondary winding 2 is placed in the coil case 11.
2. After assembling the components such as the primary winding 20, the central core 18, and the like, a high-voltage tower 38
Assemble. At this time, the tower-side high-voltage terminal 29 is inserted into the terminal insertion hole 31 of the terminal holder 25 from below, and the tower-side high-voltage terminal 29 is sandwiched and connected to the U-shaped winding-side high-voltage terminal 26.

The high voltage terminal 29 on the tower side is connected to the high voltage terminal 2 on the winding side.
In the state before being sandwiched between the high voltage terminals 6 (the state shown in FIG. 4), the distance between both sides of the high voltage terminal 26 on the winding side is smaller than the diameter of the high voltage terminal 29 on the tower side. When sandwiched between the high-side terminals 26, as shown in FIGS. 3 and 4, both sides of the high-side terminals 26 are pushed out. In this state, a force that pushes the tower-side high-voltage terminal 29 toward the opening side of the winding-side high-voltage terminal 26 indicated by the arrow A acts due to the springback force of both sides of the winding-side high-voltage terminal 26.

In this case, the terminal insertion hole 3 of the terminal holding portion 25
1, the positioning protrusions 32 and 33 are formed on the inner peripheral portion, so that the lower end (terminal holding portion 25) of the secondary spool 21 is opposite to the arrow A due to the springback force of the winding-side high-voltage terminal 26. The displacement in the direction is determined by the positioning projections 32, 33.
Thus, the lower end portion (terminal holding portion 25) of the secondary spool 21 can be accurately positioned with respect to the tower side high voltage terminal 29. That is, the positioning projections 32 and 33 play a role of centering the lower end of the secondary spool 21, and can improve the concentric accuracy between the components in the coil case 11 and can improve the insulation.

If the clearance is reduced by reducing the inner diameter of the terminal insertion hole 31 in order to increase the concentric accuracy, it becomes difficult to insert the tower side high voltage terminal 29 into the terminal insertion hole 31 and the assembling workability is reduced. However, in the present embodiment, it is not necessary to reduce the inner diameter of the terminal insertion hole 31 because the concentric accuracy is improved by the positioning projections 32 and 33. Furthermore, when the tower side high voltage terminal 29 is inserted into the terminal insertion hole 31, the tower side high voltage terminal 29 is
2 and 33, the contact and press contact area is small, so that the contact and press contact resistance at the time of insertion is not so large, and the tower side high voltage terminal 29 can be relatively easily inserted into the terminal insertion hole 31. Can be plugged in.

In this embodiment, since the terminal holding portion 25 and the positioning protrusions 32, 33 are formed of an insulating resin together with the secondary spool 21, the tower-side high-voltage terminal 29 is connected to the positioning protrusions 32, 33. When pressed, the positioning projections 32, 33 are deformed accordingly, so that the contact / pressure contact resistance by the positioning projections 32, 33 at the time of insertion is small, and the assembling workability is not impaired.

In this embodiment, since three positioning projections 32 and 33 are formed on the inner periphery of the terminal insertion hole 31,
The tower-side high-voltage terminal 29 can be accurately positioned at the center of the terminal insertion hole 31, and concentric accuracy between the two can be improved. This effect can be obtained even if four or more positioning projections are formed.
Obtained similarly.

Of course, two or only one positioning protrusion may be formed on the inner peripheral portion of the terminal insertion hole 31. Even in this case, the intended object of the present invention is sufficiently achieved. Can be. Further, the shape of the winding-side high-voltage terminal 26 is not limited to a substantially U-shape, and may be formed in a substantially V-shape.

In addition, the present invention is not limited to the stick type ignition coil, but can be applied to an ignition coil having a connection part of a high voltage terminal between a secondary winding and a high voltage tower.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an ignition coil showing an embodiment of the present invention.

FIG. 2 is an enlarged longitudinal sectional view showing a structure around a high voltage terminal connection portion between a secondary winding and a high voltage tower.

FIG. 3 is an enlarged cross-sectional view taken along the line III-III in FIG. 2;

FIG. 4 is an enlarged bottom view around the terminal holding portion showing a state before the tower-side high-voltage terminal is inserted into the winding-side high-voltage terminal.

FIG. 5 is an enlarged bottom view of the periphery of the terminal holding portion showing a state in which the tower side high voltage terminal is inserted into the winding side high voltage terminal.

6A and 6B show a conventional structure, in which FIG. 6A is an enlarged bottom view around a terminal holding portion showing a state before a tower-side high-voltage terminal is inserted into a winding-side high-voltage terminal, and FIG. Enlarged bottom view of the area around the terminal holder showing the state where the tower side high voltage terminal is inserted into the

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Ignition coil, 11 ... Coil case, 12 ... Head case, 14 ... Connector housing, 15 ... Pedestal, 16 ...
Igniter, 18: Center core, 19: Outer core, 20 ...
Primary winding, 21 ... Secondary spool, 22 ... Secondary winding, 2
5: Terminal holding part, 26: Winding side high voltage terminal, 29: Tower side high voltage terminal, 30: Filling material, 31: Terminal insertion hole, 32,
33: positioning convex portion, 34: tapered surface, 39: terminal cup, 40: spring.

Claims (4)

[Claims] 1. A terminal holding portion is provided at a lower end of a spool around which a secondary winding is wound, and a winding-side high-voltage terminal connected to one end of the secondary winding is attached to the terminal holding portion. In the high-voltage tower unit connected to the plug, a tower-side high-voltage terminal is projected upward, and the tower-side high-voltage terminal is sandwiched between the winding-side high-voltage terminals and connected to the ignition coil. A linear conductor is bent into a substantially U-shape or a substantially V-shape, and a terminal insertion hole into which the tower-side high-voltage terminal is inserted is formed in the terminal holding portion, and an inner periphery of the terminal insertion hole is formed. An ignition coil, wherein a positioning projection for positioning the tower-side high-voltage terminal is formed in the portion. 2. The device according to claim 1, wherein the positioning projection is formed at least in a portion of an inner peripheral portion of the terminal insertion hole which is located on an opening side of the winding-side high voltage terminal. The ignition coil according to claim 1. 3. The ignition coil according to claim 1, wherein the positioning protrusion is formed at at least three places on an inner peripheral portion of the terminal insertion hole. 4. The ignition coil according to claim 1, wherein a lower portion of the positioning projection is formed on an inclined surface which is inclined obliquely upward toward an inner peripheral side.