JP2007242960A - Ignition coil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ignition coil capable of improving assembly properties and bending strength when assembling a coil section and a connector case section via a cylindrical fitting member. <P>SOLUTION: In the ignition coil 1, the connector case section 3 is assembled to one axial end side D1 in the coil section 2 having a primary coil 21 and a secondary coil 22 via the cylindrical fitting member 4. A central core 23 made of a magnetic material is arranged at the inner-periphery sides of the primary coil 21 and the secondary coil 22. An outer-periphery core 24 made of a magnetic material is arranged at the outer-periphery side of the primary coil 21 and the secondary coil 22. In the fitting member 4, the outer periphery is inserted into the fitting hole 31 formed at the connector case section 3, the outer-periphery core 24 is inserted into the inner periphery, and an elastic material 52 having a Young's modulus that is lower than that of a thermoplastic resin for composing the fitting member 4 is buried into one portion of the fitting member 4. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ignition coil used for generating a spark from a spark plug in an internal combustion engine.

  In an ignition coil used for an internal combustion engine such as an engine, a primary coil formed by winding an electric wire around a primary spool and a secondary coil formed by winding an electric wire around a secondary spool are arranged concentrically. In addition, a central core made of a magnetic material is arranged on the inner peripheral side of the primary coil and the secondary coil, and an outer peripheral core made of a magnetic material is arranged on the outer peripheral side of the primary coil and the secondary coil. A magnetic path passing through the core is formed. A gap generated in the ignition coil is filled with a thermosetting resin such as an epoxy resin.

Also, stick-type ignition coils are often used in which the coil portion including the primary coil, the secondary coil, the central core, and the outer core is disposed in the plug hole of the engine. In this ignition coil, a connector case portion is disposed on one end side in the axial direction of the coil portion, and a connector portion for supplying power to the primary coil and the ignition coil are fixed to the engine in the connector case portion. The mounting flange portion is formed.
Moreover, as an ignition coil of such a shape, for example, there is a stick-type ignition coil of Patent Document 1.

In the ignition coil of Patent Document 1, a connector case part (control part) is assembled to one end side in the axial direction of the coil part via a cylindrical fitting member (terminal assembly). The fitting member has a function of preventing leakage of the epoxy resin filled in the gap in the ignition coil and a function as an attachment part of the energization terminal.
Moreover, in patent document 1, the annular groove for making this fitting member bend easily is formed in the fitting member. When the coil portion is press-fitted into the connector case portion via the fitting member, the fitting member is bent by the annular groove to prevent the fitting member from being broken.

However, in the ignition coil disclosed in Patent Document 1, nothing is filled in the annular groove formed in the fitting member. Therefore, even if the assembling property of the ignition coil can be improved, the bending strength of the ignition coil when used in the engine is lowered.
That is, when the coil portion is disposed in the plug hole and the ignition coil is assembled to the engine, when a bending load due to engine vibration acts on the ignition coil, stress tends to concentrate on the fitting member. In order to secure sufficient bending strength that can withstand breakage in the ignition coil, further ingenuity has been required.

JP 2005-260209 A

  The present invention has been made in view of such conventional problems, and can improve assemblability and bending strength when the coil portion and the connector case portion are assembled through a cylindrical fitting member. An attempt is made to provide an ignition coil.

The present invention relates to an ignition coil in which a connector case portion having a connector portion and a mounting flange portion is assembled to one end side in the axial direction of a coil portion having a primary coil and a secondary coil via a cylindrical fitting member. In
A central core made of a magnetic material is arranged on the inner peripheral side of the primary coil and the secondary coil, and an outer peripheral core made of a magnetic material is arranged on the outer peripheral side of the primary coil and the secondary coil. ,
The fitting member is formed by fitting the outer periphery of the fitting member into a fitting hole formed in the connector case portion, and fitting the outer peripheral core on the inner periphery of the fitting member. The ignition coil is characterized in that an elastic material having a Young's modulus lower than that of the constituent material is embedded.

The ignition coil according to the present invention is of a stick type in which the coil portion is disposed in a plug hole of an engine.
The ignition coil of the present invention is formed by dividing the coil portion and the connector case portion, and the connector case portion is assembled to one end side in the axial direction of the coil portion via a cylindrical fitting member. Further, the outer periphery of the fitting member is fitted into a fitting hole formed in the connector case portion, and the outer peripheral core in the coil portion is fitted into the inner periphery of the fitting member.

In the present invention, an elastic material having a Young's modulus lower than that of the material constituting the fitting member is embedded in a part of the fitting member.
Therefore, when a coil part formed by assembling a primary coil, a secondary coil, a center core, and an outer core is inserted into a fitting hole in a coil case part via a fitting member, a part of the fitting member is elastic. Since the material is embedded, the fitting member can be appropriately deformed. Thereby, the assembly property of an ignition coil can be improved.

Moreover, by embedding the elastic material in the fitting member, the groove part which forms an air layer in the fitting member is not formed, and the fall of the intensity | strength of a fitting member can be suppressed small.
Therefore, in a state where the coil portion is disposed in the plug hole and the ignition coil is assembled to the engine, a bending load due to engine vibration acts on the ignition coil, and stress due to the bending load is concentrated on the fitting member. Even when it acts, this fitting member can be prevented from being damaged, and the ignition coil can be prevented from being broken.
Therefore, according to the present invention, it is possible to provide an ignition coil that can improve the assembling property and the bending strength when the coil portion and the connector case portion are assembled via the cylindrical fitting member. .

A preferred embodiment of the present invention described above will be described.
In the present invention, the fitting member has an outer periphery on one end side in the axial direction fitted into the fitting hole, and an outer circumference core on the inner circumference on the other end side in the axial direction. The material can be embedded in the fitting member from the one end side in the axial direction (Claim 2).
In this case, it is easy to embed an elastic material in a part of the fitting member.

The fitting member has an outer periphery on the other end side in the axial direction inserted into the fitting hole, and an outer periphery core on the inner periphery on the other end side in the axial direction. Can also be embedded in the fitting member from the other axial end side.
Also in this case, it is easy to embed an elastic material in a part of the fitting member.

The fitting member is preferably made of a thermoplastic resin, and the elastic material is preferably made of a resin, rubber (particularly an elastomer) or gel having a Young's modulus lower than that of the thermoplastic resin.
In this case, an elastic material having a Young's modulus lower than that of the thermoplastic resin constituting the fitting member can be easily selected.
The resin or rubber can also be a foam.

  The fitting member is made of metal or ceramics, and the elastic material is made of metal, ceramics, resin, rubber (especially elastomer) or gel having a lower Young's modulus than the metal or ceramics constituting the fitting member. You can also

Hereinafter, embodiments of the ignition coil according to the present invention will be described with reference to the drawings.
As shown in FIG. 1, the ignition coil 1 of the present example includes a connector case portion provided with a connector portion 32 and a mounting flange portion 33 on one axial end side D1 of the coil portion 2 provided with the primary coil 21 and the secondary coil 22. 3 is assembled through a cylindrical fitting member 4.
A central core 23 made of a magnetic material is arranged on the inner peripheral side of the primary coil 21 and the secondary coil 22, and an outer peripheral core 24 made of a magnetic material is arranged on the outer peripheral side of the primary coil 21 and the secondary coil 22. It is arranged.

As shown in FIG. 1, the fitting member 4 has an outer periphery fitted into a fitting hole 31 formed in the connector case portion 3, and an outer circumferential core 24 fitted into the inner circumference.
An elastic material 52 having a Young's modulus lower than that of the thermoplastic resin constituting the fitting member 4 is embedded in a part of the fitting member 4.

Hereinafter, the ignition coil 1 of this example will be described in detail with reference to FIGS.
As shown in FIG. 2, a plug attachment portion 6 for attaching a spark plug 65 is formed on the other axial end D2 of the ignition coil 1 of this example.
As shown in FIG. 3, the ignition coil 1 of this example has the coil portion 2 and the plug attachment portion 6 disposed in the plug hole 71 of the engine 7, and the attachment flange portion 33 in the connector case portion 3 is provided in the engine 7. It is a stick type configured to be fixed to the periphery of the plug hole 71 via a bolt 335.

As shown in FIG. 1, the connector part 32 in the connector case part 3 is a part that performs electrical connection between the ignition coil 1 and an electronic control unit (ECU) in the engine 7. The mounting flange portion 33 is a part for fixing the ignition coil 1 to the cylinder head of the engine 7. The connector portion 32 and the mounting flange portion 33 are formed so as to protrude outward in the radial direction from the connector case portion 3.
An igniter 34 as an electronic component having a power supply circuit and the like is disposed in the connector case portion 3. The connector case portion 3 formed with the connector portion 32 and the mounting flange portion 33 is made of a thermoplastic resin. The fitting member 4 is also formed from a thermoplastic resin.

  As shown in FIGS. 1 and 2, the primary coil 21 of this example is formed by winding a primary wire with insulation coating on the outer peripheral surface of a primary spool 211 made of a thermoplastic resin having a circular cross section. The secondary coil 22 of this example has more secondary wires coated with an insulating coating having a smaller diameter than the primary wires on the outer peripheral surface of the secondary spool 221 made of a thermoplastic resin formed in an annular cross section. It is wound by the number of windings. The secondary coil 22 of this example is inserted and arranged on the inner peripheral side of the primary coil 21. Further, the central core 23 is inserted and arranged on the inner peripheral side of the secondary coil 22.

In addition, a coil case 25 made of a thermoplastic resin formed in an annular cross section is disposed on the outer peripheral side of the primary coil 21.
The central core 23 in this example is formed by laminating flat electromagnetic steel plates (silicon steel plates or the like) in the radial direction of the ignition coil 1 and having a substantially circular cross section. The outer peripheral core 24 of this example is formed by laminating electromagnetic steel plates (silicon steel plates or the like) formed in a cylindrical shape along the shape of the outer peripheral surface of the coil case 25. The outer peripheral core 24 of this example is disposed on the outer periphery of the coil case 25.

As shown in FIG. 2, the plug attachment portion 6 of this example is obtained by attaching a rubber plug cap 61 to an attachment base portion 212 that is extended from the other axial end D <b> 2 of the primary spool 211. Further, a high voltage terminal 62 is disposed on the other axial end D2 of the secondary spool 221, and a coil spring 63 for contacting the terminal portion of the spark plug 65 is attached to the high voltage terminal 62. The winding end portion on the high voltage side of the secondary coil 22 is electrically connected to the terminal portion of the spark plug 65 through the high voltage terminal 62 and the coil spring 63.
Further, the spark plug 65 is engaged with a hollow hole formed in the plug cap 61 and the terminal portion formed at the tip of the insulator portion is fixed to the cylinder head of the engine 7 with the coil spring 63 being in contact therewith. Is done.

  As shown in FIG. 1, the fitting member 4 of this example is made of a thermoplastic resin formed in a cylindrical shape (annular cross section). The other end D2 in the axial direction of the fitting member 4 is formed with a fitting portion 43 for fitting the outer periphery thereof into the fitting hole 31 in the connector case portion 3 and fitting the outer peripheral core 24 into the inner periphery thereof. It is. A holding portion 44 for fitting the coil case 25 is formed on one end D1 in the axial direction of the fitting member 4.

  The elastic material 52 of this example is embedded in the fitting portion 43 formed on the other axial end D2 of the fitting member 4. The elastic material 52 is disposed in an annular groove 431 formed along the circumferential direction of the fitting portion 43. The elastic material 52 can be embedded in the fitting member 4 by insert molding when the fitting member 4 is molded. Insert molding can be performed by filling the molding die with a resin material in a state where the elastic material 52 is disposed in the molding die when the fitting member 4 is molded.

As shown in FIG. 1, an annular fitting groove 432 for fitting the outer core 24 is formed on the inner circumference of the fitting portion 43. The end of the outer peripheral core 24 on the one end side D <b> 1 in the axial direction is fitted into the fitting groove 432 in the core fitting portion 42 of the fitting member 4.
Further, the seal member 55 of this example is mounted on an extension forming portion 311 formed by extending a portion forming the fitting hole 31 of the connector case portion 3 toward the other axial end side D2.

The thermoplastic resin constituting the fitting member 4 of this example is made of PBT (polybutylene terephthalate). The elastic material 52 embedded in the fitting member 4 is made of an elastomer having a Young's modulus and hardness lower than those of the thermoplastic resin, and the Young's modulus and hardness of the elastic material 52 are those of the thermoplastic resin constituting the fitting member 4. It is lower than Young's modulus and hardness.
The thermoplastic resin can be composed of various thermoplastic resins other than PBT, and the elastic material 52 can be composed of a resin foam other than the elastomer.

As shown in FIG. 2, the end of the coil case 25 of this example on the one end side D1 in the axial direction is fitted into the inner periphery of the holding portion of the fitting member 4, and the end of the other end D2 in the axial direction of the coil case 25. The end portion is fitted to the attachment base portion 212 of the primary spool 211.
Further, the gap between the ignition coil 1 surrounded by the connector case portion 3, the fitting member 4, the coil case 25, the mounting base portion 212, and the high voltage terminal 62 is filled with the thermosetting resin 11 made of epoxy resin or the like. It is. The thermosetting resin 11 includes a gap between the central core 23 and the secondary coil 22, a gap between the secondary coil 22 and the primary coil 21, and a gap between the primary coil 21 and the coil case 25. And a gap in the connector case 3 is filled. The thermosetting resin 11 is obtained by filling the ignition coil 1 and filling the gap (space) formed after the assembly with the liquid thermosetting resin 11 and curing it. .

Further, as shown in FIGS. 4 and 5, the elastic material 52 can be embedded in the end portion of the fitting member 4 on the one end side D <b> 1 in the axial direction. In this case, a case fitting portion 41 for fitting into the fitting hole 31 in the connector case portion 3 is formed at one end D1 in the axial direction of the fitting member 4, and the other axial end of the fitting member 4 is formed. A core fitting portion 42 for fitting the outer peripheral core 24 can be formed on the side D2. In this case, the first fitting portion A1 where the case fitting portion 41 of the fitting member 4 and the connector case portion 3 are fitted, the core fitting portion 42 of the fitting member 4 and the outer core 24 are provided. The second fitting portion A2 to be fitted can be formed so as to be shifted in the axial direction D so as not to overlap with each other in the axial direction D of the ignition coil 1.
Further, in this case, the seal member 55 can be attached to the outer periphery of the core fitting portion 42 as shown in FIG. 4, while it is attached to the extension forming portion 311 in the connector case portion 3 as shown in FIG. You can also

  In the ignition coil 1, when a current is passed through the primary coil 21 by a pulsed spark generation signal from the ECU, a magnetic field that passes through the central core 23 and the outer peripheral core 24 is formed. Next, when the current flowing through the primary coil 21 is interrupted, an induction magnetic field passing through the central core 23 and the outer peripheral core 24 is formed in a direction opposite to the magnetic field formation direction. Then, due to the formation of the induction magnetic field, a high voltage induced electromotive force (back electromotive force) is generated in the secondary coil 22, and a spark can be generated from the spark plug 65 attached to the plug attachment portion 6 in the ignition coil 1. it can.

In the ignition coil 1 of this example, as described above, an elastic material 52 having a Young's modulus lower than that of the thermoplastic resin constituting the fitting member 4 is embedded in a part of the fitting member 4.
Therefore, when fitting the coil part 2 formed by assembling the primary coil 21, the secondary coil 22, the center core 23 and the outer core 24 into the fitting hole 31 in the connector case part 3 via the fitting member 4. Since the elastic material 52 is embedded in a part of the fitting member 4, the fitting member 4 can be appropriately deformed. Thereby, the assembly property of the ignition coil 1 can be improved.

Moreover, by embedding the elastic material 52 in the fitting member 4, the groove part which forms an air layer is not formed in the fitting member 4, and the fall of the intensity | strength of the fitting member 4 can be suppressed small.
Therefore, when the coil portion 2 is disposed in the plug hole 71 and the ignition coil 1 is assembled to the engine 7, a bending load due to the vibration of the engine 7 acts on the ignition coil 1, and the fitting member 4 is bent. Even when stress due to load is concentrated and acting, the fitting member 4 can be prevented from being damaged, and the ignition coil 1 can be prevented from being broken.
Therefore, according to the ignition coil 1 of this example, it is possible to improve the assemblability and the bending strength when the coil portion 2 and the connector case portion 3 are assembled via the cylindrical fitting member 4.

Cross-sectional explanatory drawing which shows the whole ignition coil in an Example. Sectional explanatory drawing which shows the periphery of the connector case part of an ignition coil in an Example. Cross-sectional explanatory drawing which shows the ignition coil of the state attached to the engine in an Example. Sectional explanatory drawing which shows the periphery of the connector case part of another ignition coil in an Example. Sectional explanatory drawing which shows the periphery of the connector case part of another ignition coil in an Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ignition coil 11 Thermosetting resin 2 Coil part 21 Primary coil 22 Secondary coil 23 Central core 24 Outer core 3 Connector case part 31 Fitting hole 32 Connector part 33 Mounting flange part 4 Fitting member 43 Fitting part 431 Annular groove 432 Insertion groove 44 Holding part 52 Elastic material 55 Seal member 6 Plug mounting part 7 Engine 71 Plug hole D Axial direction D1 Axial direction one end D2 Axial direction other end

Claims (4)

In an ignition coil formed by assembling a connector case portion provided with a connector portion and a mounting flange portion via a cylindrical fitting member on one end side in the axial direction of a coil portion provided with a primary coil and a secondary coil,
A central core made of a magnetic material is arranged on the inner peripheral side of the primary coil and the secondary coil, and an outer peripheral core made of a magnetic material is arranged on the outer peripheral side of the primary coil and the secondary coil. ,
The fitting member is formed by fitting the outer periphery of the fitting member into a fitting hole formed in the connector case portion, and fitting the outer peripheral core on the inner periphery of the fitting member. An ignition coil characterized in that an elastic material having a lower Young's modulus than a constituent material is embedded. In claim 1, the fitting member is formed by fitting the outer periphery on one end side in the axial direction into the fitting hole, and fitting the outer peripheral core on the inner periphery on the other end side in the axial direction.
The ignition coil, wherein the elastic material is embedded in the fitting member from one end side in the axial direction. In claim 1, the fitting member is formed by fitting the outer periphery on the other end side in the axial direction into the fitting hole, and inserting the outer core on the inner circumference on the other end side in the axial direction.
The ignition coil, wherein the elastic material is embedded in the fitting member from the other axial end side.   The fitting member according to any one of claims 1 to 3, wherein the fitting member is made of a thermoplastic resin, and the elastic material is made of a resin, rubber, or gel having a Young's modulus lower than that of the thermoplastic resin. Ignition coil to play.

Images