JP2003332153A - Ignition coil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ignition coil where a jointing strength between a connector-side terminal and an igniter-side terminal is large while the cost for jointing the connector-side terminal to the igniter-side terminal is suppressed to a conventional level. <P>SOLUTION: The ignition coil comprises a connector which has a connector- side terminal connected electrically to an engine controller, an igniter which has an igniter-side terminal connected electrically to the connector-side terminal, and a housing which houses the igniter. A connector-side jointing part 400 provided to a connector-side terminal 40 is jointed to an igniter-side jointing part 300 provided to an igniter-side terminal 30 by resistance welding in which one jointing part wraps around the other jointing part. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ignition coil, and more particularly to an ignition coil incorporating an igniter.

[0002]

2. Description of the Related Art An ignition coil incorporating an igniter has been developed in order to eliminate the need for wiring connecting the igniter and the ignition coil and to reduce the mounting space for the igniter and the ignition coil. A top view of this type of ignition coil is shown in FIG. As shown, the ignition coil 100
Is a housing 101, a connector 102, and an igniter 1.
03 and. The housing 101 forms the outer shell of the ignition coil 100. The upper end of the housing 101 has a rectangular tube shape. In addition, a window portion 105 is opened in a notch shape at the upper end portion of the housing 101. The igniter 103 is arranged substantially at the center of the upper end of the housing 101. An igniter-side terminal 104 extends outward from the igniter 103.
The connector 102 is provided so as to project from the window 105 toward the outside of the housing 101. The connector 102 is electrically connected to an engine control device (hereinafter appropriately referred to as “ECU”). A connector-side terminal 106 extends inward from the connector 102. Then, the connector side terminal 106 and the igniter side terminal 104
Are joined in a narrow gap 107 defined by the connector 102 and the igniter 103, as indicated by the mark X in the figure.

FIG. 9 shows a process of joining the connector side terminal and the igniter side terminal. In joining, first, the lower surface of the connector-side joint portion 108 of the connector-side terminal 106 and the upper surface of the igniter-side joint portion 109 of the igniter-side terminal 104 are brought into contact with each other. Subsequently, as shown by the arrow in the figure, the contact portion is sandwiched by the positive electrode 110 and the negative electrode 111 in this state. Then, the positive electrode 110 → the connector side joint 108 → the igniter side joint 109 → the negative electrode 11
Energize in the order of 1. Then, due to Joule heat during energization, the connector-side joint 108 and the igniter-side joint 10
9 and 9 are resistance welded. In this way, the connector side terminal 106 and the igniter side terminal 104 are joined.

[0004]

The joint strength between the connector side joint 108 and the igniter side joint 109 is proportional to the joint area of both joints. In this respect, the joint area between the conventional connector-side joint portion 108 and the igniter-side joint portion 109 is relatively small. Therefore, the joint strength of both joints is relatively small. To increase the bonding area, for example,
Connector-side joint portion 108 and igniter-side joint portion 10
9 may be extended in the longitudinal direction of the terminal. However, if these two joints are extended in the longitudinal direction of the terminal, the positive electrode 110 and the negative electrode 111 for welding both joints must also be extended in the longitudinal direction of the terminal. This requires another new resistance welder. Therefore, the cost required for the joining process and the manufacturing cost of the ignition coil are increased.

The ignition coil of the present invention has been completed in view of the above problems. Therefore, an object of the present invention is to provide an ignition coil in which the joining cost between the connector side terminal and the igniter side terminal is suppressed to the conventional level and the joining strength between the connector side terminal and the igniter side terminal is large.

[0006]

(1) In order to solve the above problems, an ignition coil according to the present invention has a connector having a connector side terminal electrically connected to an engine control device, and an electrical connection to the connector side terminal. An ignition coil for applying a high voltage to an ignition plug, comprising an igniter having electrically connected igniter-side terminals and a housing for accommodating the igniter, and a connector-side joint portion of the connector-side terminals And the igniter-side joining portion of the igniter-side terminal are joined by wrapping the other joining portion with one joining portion and performing resistance welding.

That is, in the ignition coil of the present invention, one of the connector side joint portion and the igniter side joint portion is wrapped around the other joint portion, and resistance welding is performed in this state, whereby the connector side terminal and the igniter are joined. The side terminals are joined together.

As shown in FIG. 9 described above, conventionally, the joint strength is secured by the lower surface of the connector side joint portion 108 and the upper surface of the igniter side joint portion 109. That is, the bonding strength was secured only between the surfaces of the two bonded portions facing each other. Therefore, the joint area was small.

In this respect, the ignition coil of the present invention has one of the connector side joint portion and the igniter side joint portion wrapped around the other joint portion. Therefore, a wide bonding area can be secured. Therefore, according to the ignition coil of the present invention, the joint strength between the connector side terminal and the igniter side terminal is increased.

Further, since the one joint portion wraps the other joint portion, the lengths of both joint portions in the longitudinal direction of the terminal are almost the same as those in the conventional case. Therefore, it is possible to weld both joints with the same resistance welding machine as the conventional one. Therefore, the joining cost can be suppressed to the conventional level.

(2) Preferably, at least one of the connector-side joint portion and the igniter-side joint portion has a structure made of a soluble metal that is melted by welding heat.

For example, when a commercially available terminal is purchased for an igniter-side terminal or a connector-side terminal, a film made of a soluble alloy such as Ni is often formed from the beginning. Therefore, according to the conventional method (see FIG. 9) in which the other terminal is simply placed on the other terminal and resistance welding is performed, the coating may be an obstacle and the desired bonding strength may not be obtained. Then, in order to secure a desired joint strength, it is necessary to remove the coating before welding.

In this respect, according to the ignition coil of the present invention, since one joint portion wraps the other joint portion,
Originally the joint strength is high. Therefore, even if the terminal having the coating is used as it is for the igniter-side terminal or the connector-side terminal, a desired joining strength can be easily obtained. Therefore, the ignition coil of the present invention is suitable for being embodied as an ignition coil in which at least one of the connector-side joint and the igniter-side joint has a coating.

(3) Preferably, the housing is provided with a window portion, the connector is provided so as to project from the window portion to the outside of the housing, and the igniter is housed substantially in the center of the housing. Therefore, it is preferable that the connector-side joint portion and the igniter-side joint portion are joined in a narrow gap defined by the connector and the igniter in the housing.

That is, in this structure, the connector-side joint portion and the igniter-side joint portion are joined in a narrow gap. Bonding strength is proportional to the width of the bonding area.
Therefore, in order to increase the bonding area in the narrow gap 107 shown in FIG.
For example, the connector side joint portion 108 and the igniter side joint portion 109 may be extended in the lateral direction of the terminal, that is, in the width direction. However, if these two joints are extended in the width direction, there is a risk of interference with another terminal pair adjacent in the width direction. In order to prevent interference, high welding accuracy is required. Therefore, the welding work becomes difficult.

On the other hand, the connector side joint portion and the igniter side joint portion of the ignition coil of the present invention are welded so that one joint portion wraps around the other joint portion. Therefore, according to the ignition coil of the present invention, it is possible to secure a wide joint area without extending both joint portions in the width direction. Therefore, the ignition coil of the present invention is suitable for embodying as an ignition coil in which the connector-side joint and the igniter-side joint are joined together in a narrow space.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of an ignition coil according to the present invention will be described below.

(1) First Embodiment First, the structure of the ignition coil of this embodiment will be described. FIG. 1 shows an external view of the ignition coil device 1 of this embodiment. As shown in the figure, the ignition coil 1 includes a housing 2, an igniter 3, a connector 4 and a plug cap 5.

The housing 2 is made of resin and forms the outer shell of the ignition coil 1. Upper end 20 of housing 2
The other parts have a cylindrical shape. And the upper end 2
Portions other than 0 are inserted into plug holes (not shown). A cylindrical plug cap 5 made of rubber is fitted to the lower end of the housing 2. Plug cap 5
An ignition plug (not shown) is press-fitted on the inner peripheral side of the.
Further, inside the housing 2, members such as a central core, a primary coil and a secondary coil are housed in order to apply a high voltage to the ignition plug. Further, the interior of the housing 2 is filled with an epoxy resin 6 (shown by a chain line in the figure) that ensures insulation between the respective members.

On the other hand, the upper end portion 20 of the housing 2 has a rectangular tubular shape. A window portion 21 is opened in the side wall of the upper end portion 20 in a notch shape. The connector 4 is made of resin and has a rectangular tubular shape. The connector 4 is provided so as to project from the window portion 21 to the outside of the upper end portion 20. The igniter 3 is formed by covering a circuit portion, a power transistor, and the like with a molding resin. The igniter 3 is housed in approximately the center of the upper end portion 20.

FIG. 2 shows a top view of the ignition coil of this embodiment. The epoxy resin is omitted for convenience of explanation. As shown in the figure, a narrow gap 22 is defined between the igniter 3 and the connector 4. An igniter-side terminal 30 extends outward from the igniter 3. The igniter-side terminal 30 is electrically connected to the circuit section inside the mold resin. An igniter-side joining portion 300 is arranged at the tip of the igniter-side terminal 30. The igniter side terminals 30 are parallel to each other,
A total of four are arranged.

The connector 4 is electrically connected to the ECU. From the connector 4, connect the igniter side terminal 3
The terminal 40 on the connector side faces 0 and extends inward. That is, the connector side terminal 40 is an EC
It is electrically connected to U. The connector-side joint portion 400 is arranged at the tip of the connector-side terminal 40. The connector-side terminals 40 are also arranged in parallel with each other in total of four. Then, the connector-side terminal 40 and the igniter-side terminal 30 are connected to each other by the connector-side joint portion 4 as indicated by a cross in the drawing.
00 wraps the igniter side joint portion 300 from below and is resistance-welded to be joined.

Next, the movement of the ignition coil of this embodiment will be described. The electric signal from the ECU is transmitted to the circuit portion of the igniter 3 via the connector side terminal 40 and the igniter side terminal 30. By the electric signal transmitted,
The igniter 3 interrupts the current supplied to the primary coil.
When the current is interrupted, a high voltage is generated in the secondary coil due to the mutual induction effect. This high voltage is applied to the spark plug.

Next, the joining process at the time of manufacturing the ignition coil of this embodiment will be described. In the joining process,
As shown in FIG. 3, first, a T-shaped connector-side joint 40
The igniter side joint 3
Place 00. Subsequently, as indicated by the arrow in the drawing, the bent portions 401 extending on both sides in the width direction of the base portion 402 are bent upward. Then, as shown in FIG.
Thus, the igniter side joint portion 300 is wrapped. Then, in this state, as shown by the arrow in FIG. 5, the positive electrode 70 is pressed from above the bent portion 401. Further, the negative electrode 71 is pressed against the base portion 402 from below. That is, the connector-side joint 400 is sandwiched between the positive electrode 70 and the negative electrode 71 while the igniter-side joint 300 is sandwiched. Then, in this state, the positive electrode 70, the bent portion 401, the igniter side joint portion 300, the base portion 402, and the negative electrode 71 are energized in this order. Due to Joule heat during energization, the lower surface of the bent portion 401 and the igniter-side joining portion 3
00 upper surface is welded. In addition, the igniter side joint portion 30
0 lower surface and the base 402 upper surface are welded.

Next, the effect of the ignition coil of this embodiment will be described. The connector-side terminal 40 and the igniter-side terminal 30 are joined by resistance welding with the connector-side joining portion 400 enclosing the igniter-side joining portion 300. Therefore, at the two interfaces of the bent portion 401 lower surface and the igniter side joint portion 300 upper surface, and the igniter side joint portion 300 lower surface and the base portion 402 upper surface,
The connector side joint portion 400 and the igniter side joint portion 300 are welded. Therefore, the joint area of both joints is
Compared to the joint area of both joints in the conventional ignition coil (see FIG. 9), it is almost doubled. Therefore, in the ignition coil device 1 of this embodiment, the joint strength between the connector side terminal 40 and the igniter side terminal 30 is large.

Further, according to the ignition coil device 1 of this embodiment, the igniter-side joint portion 300 is sandwiched between the base portion 402 and the bent portion 401. Also in the point that this clamping force acts, the ignition coil 1 of the present embodiment has a large joint strength between the connector side terminal 40 and the igniter side terminal 30.

Further, according to the ignition coil device 1 of this embodiment, the bonding interfaces are vertically stacked. For this reason, conventional electrodes can be used as the positive electrode 70 and the negative electrode 71. That is, it is not necessary to dispose a new resistance welding machine separately. Therefore, the joining cost can be suppressed to the conventional level.

Further, according to the ignition coil device 1 of this embodiment, although the connector-side terminal 40 and the igniter-side terminal 30 are arranged in the narrow gap 22, the space between the terminal pairs is sufficiently secured. . Therefore, the welding operation can be performed without worrying about the interference with the adjacent terminal pair.

(2) Second Embodiment The difference between this embodiment and the first embodiment is that the connector-side joint is not L-shaped but L-shaped. In addition, the igniter side joint is covered with a coating. Therefore, only the differences will be described here.

FIG. 6 shows the connector side joint and the igniter side joint before resistance welding. The parts corresponding to those in FIG. 3 are indicated by the same symbols. As shown in the figure, the connector-side joint portion 400 is L-shaped. That is, the connector-side joint portion 400 includes a base portion 402 extending in the terminal longitudinal direction and a bent portion 401 that is bent at approximately 90 ° in the width direction with respect to the base portion. Further, the igniter-side joint portion 300 has a linear shape. The surface of the igniter-side joint portion 300 is covered with the coating 8 formed by Ni plating. That is, the igniter side terminal 30 is a commercial product.

In the joining process, first, as shown in the figure, the base portion 402 is brought into contact with the lower surface of the igniter-side joining portion 300. Then, as shown by the arrow in the figure, the bent portion 40
Bend 1 upward. Then, as shown in FIG.
The igniter-side joint portion 300 is wrapped in a U-shape by the bent portion 401. After that, resistance welding is performed in this state. The coating 8 is melted by the Joule heat generated during resistance welding. Then, the igniter side joint portion 300 and the connector side joint portion 400 are resistance-welded. In this way, the igniter side terminal 30 and the connector side terminal 40 are joined.

When a commercially available terminal is purchased as a component, the Ni plating treatment is often applied from the beginning. That is, the coating 8 is often formed. Therefore,
According to the conventional method (see FIG. 9) in which the other terminal is simply placed on the other terminal and resistance welding is performed (see FIG. 9), the coating 8 may be an obstacle and the desired bonding strength may not be obtained. Then, in order to secure the desired joint strength, it is necessary to peel off the coating film 8 before welding.

In this respect, according to the ignition coil device 1 of this embodiment, a wide bonding area is ensured by stacking in the vertical direction. In addition, the bending portion 401 allows the igniter-side joining portion 30
0 is sandwiched. Therefore, even if a commercially available terminal is used as it is, it is possible to easily secure a desired bonding strength.

(3) Others The embodiments of the ignition coil of the present invention have been described above. However, the embodiment is not particularly limited to the above embodiment. Various modifications and improvements can be made by those skilled in the art.

For example, in the above embodiment, the connector-side joint portion 400 has a T-shape or L-shape, but the shapes of the connector-side joint portion 400 and the igniter-side joint portion 300 are not particularly limited. Further, the connector-side joint portion 400 is bent in the first embodiment, and the bent portion 401 is bent in the second embodiment. However, the igniter-side joint portion 300 may be bent. In addition, in the second embodiment, the coating 8 is formed on the igniter-side joint portion 300.
However, the coating 8 may be arranged on the connector-side joint portion 400. Alternatively, the coating film 8 may be arranged on both joints. The coating 8 was formed by Ni plating. However, for example, Bi, Pb, In, Ag, Cu, Sn
The coating 8 may be formed of another soluble metal including, for example, Further, in the second embodiment, the bent portion 401 has the base portion 402.
Although the bent portion 401 is bent from the horizontal state, the bent portion 401 may be bent 90 ° in advance with respect to the base portion 402.

[0036]

According to the present invention, it is possible to provide an ignition coil in which the joining cost between the connector side terminal and the igniter side terminal is suppressed to the conventional level and the joining strength between the connector side terminal and the igniter side terminal is large. .

[Brief description of drawings]

FIG. 1 is an external view of an ignition coil according to a first embodiment.

FIG. 2 is a top view of an ignition coil according to the first embodiment.

FIG. 3 is a view showing a state in which both joints are brought into contact with each other in the joining process at the time of manufacturing the ignition coil according to the first embodiment.

FIG. 4 is a diagram showing a state in which both joints are sandwiched in a joining process at the time of manufacturing the ignition coil according to the first embodiment.

FIG. 5 is a view showing a state in which both joints are resistance-welded in the joining step at the time of manufacturing the ignition coil according to the first embodiment.

FIG. 6 is a view showing a state in which both joints are brought into contact with each other in a joining process at the time of manufacturing the ignition coil according to the second embodiment.

FIG. 7 is a diagram showing a state in which both joints are sandwiched in a joining process at the time of manufacturing the ignition coil according to the second embodiment.

FIG. 8 is a top view of a conventional ignition coil.

FIG. 9 is a diagram showing a state in which both joints are resistance-welded in a joining process during manufacturing of a conventional ignition coil.

[Explanation of symbols]

1: Ignition coil, 2: Housing, 20: Upper end, 2
1: window part, 22: narrow gap, 3: igniter, 30: igniter side terminal, 300: igniter side joint part, 4: connector, 40: connector side terminal, 400: connector side joint part, 401: bent part, 402 : Base, 5: plug cap, 6: epoxy resin, 70: positive electrode, 71: negative electrode, 8: coating.

Claims (3)

[Claims] 1. A connector having a connector-side terminal electrically connected to an engine control device, an igniter having an igniter-side terminal electrically connected to the connector-side terminal, and a housing for housing the igniter. An ignition coil for applying a high voltage to an ignition plug, wherein the connector side joint part of the connector side terminal and the igniter side joint part of the igniter side terminal are one joint part An ignition coil, characterized in that it is joined by wrapping the joint part of and performing resistance welding. 2. The ignition coil according to claim 1, wherein at least one of the connector-side joint portion and the igniter-side joint portion has a film made of a soluble metal that is melted by welding heat. 3. A window is opened in the housing, the connector is provided so as to project from the window to the outside of the housing, and the igniter is housed in substantially the center of the housing. The ignition coil according to claim 1, wherein the connector-side joint portion and the igniter-side joint portion are joined in a narrow gap defined by the connector and the igniter in the housing.