JP2006269461A - Ignition coil and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ignition coil in which the winding width of an axial direction of a primary winding of primary coil is stably maintained, and also to provide a manufacturing method thereof. <P>SOLUTION: The ignition coil 1 is provided with the primary coil 2 and a secondary coil. The primary coil 2 is provided with a primary spool 3 and the primary winding 4. The primary winding 4 is provided with a first layer winding 41 formed by winding a primary wire 40 from one side D1 of the axial direction of the primary spool 3 toward the other side D2 of the axial direction ; and a second layer wiring 42 formed by winding a primary wire 40 from the other side D2 of the axial direction toward the one side D1 of the axial direction in the external periphery side of the first layer winding 41. The first and second layer wiring sections 41 and 42 are formed into a roughly winding state in which winding pitches P1, P2 are larger than the external dimension A of the primary wire 40. In the first layer winding 41, a winding termination 411 positioned at the other side D2 of the axial direction is engaged on an external periphery protrusion 32 formed so as to protrude from an external peripheral surface 31 of the primary spool 3. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ignition coil for generating a spark from a spark plug in an internal combustion engine and a method for manufacturing the same.

An ignition coil used by being installed in each cylinder in an internal combustion engine such as a vehicle is inserted into a plug hole in an engine case and spark is generated from a spark plug attached to the ignition coil, thereby igniting combustion in each cylinder. It is carried out.
The ignition coil includes a primary coil and a secondary coil wound concentrically, and the primary coil is formed by winding a primary wire coated with insulation around the outer peripheral surface of a primary spool made of a cylindrical resin. Thus, the secondary coil is formed by winding a secondary electric wire coated with insulation around the outer peripheral surface of a secondary spool made of a cylindrical resin. In the ignition coil, an induced magnetic field is generated along with a magnetic field generated by energizing the primary coil instantaneously, and a spark is generated from the spark plug by an induced electromotive force generated in the secondary coil.

  Incidentally, for example, in an ignition coil such as a CDI method (capacitor-discharged ignition system), the electric charge accumulated in the capacitor is supplied to the primary coil, so that the inductance of the primary coil is relatively small. In order to reduce the inductance while maintaining the performance of the primary coil, the primary wire is wound at a winding pitch larger than its outer diameter, and a predetermined gap is provided between the primary wires, and the winding is loosely wound. The primary winding of the state is formed.

However, as shown in FIG. 10, when the primary coil 92 having the loosely wound primary winding 94 is inserted and disposed in the cylindrical part 99 having a cylindrical cross section when the ignition coil is assembled or the like, The winding 94 may come into contact with the cylindrical part 99.
At this time, when the primary winding 94 is pulled by the cylindrical part 99, the end of the primary winding 94 may be displaced in the axial direction D of the primary spool 93. And when this position shift arises, the winding width W in the axial direction D of the primary winding 94 in the primary coil 92 will become small.

Patent Document 1 discloses an internal combustion engine ignition coil in which the number of turns per unit length of the primary coil is changed. In this primary coil, in order to increase the amount of magnetic energy stored, the number of turns in the portion near the permanent magnet in the iron core inserted in the primary coil is made larger than the number of turns in the far portion.
However, in Patent Document 1, the first-layer winding is formed in a closely wound state in which the respective wound wires are in close contact with each other, and the winding does not shift in position. For this reason, no effort has been made to stably maintain the winding width in the axial direction of the winding.

Japanese Patent No. 2830367

  The present invention has been made in view of such conventional problems, and intends to provide an ignition coil capable of stably maintaining the winding width in the axial direction of the primary winding in the primary coil and a method for manufacturing the same. It is.

A first invention is an ignition coil including a primary coil and a secondary coil arranged concentrically.
The primary coil includes a primary spool having a cylindrical cross-sectional shape, and a primary winding formed by winding a primary wire having an insulating coating around the outer peripheral surface of the primary spool a plurality of times.
The primary winding is a first-layer winding portion formed by winding the primary electric wire a plurality of times from one axial direction side of the primary spool to the other axial direction side, and an outer peripheral side of the first-layer winding portion. A second-layer winding portion formed by winding the primary electric wire a plurality of times from the other axial side toward the one axial side, the second-layer winding portion and the first-layer winding portion Is a loosely wound state in which the winding pitch of the primary wire is larger than the outer diameter of the primary wire,
The first-layer winding portion is an ignition coil characterized in that a winding end portion located on the other side in the axial direction is engaged with an outer peripheral protrusion formed to protrude from the outer peripheral surface of the primary spool. (Claim 1).

The primary coil in the ignition coil of the present invention is a sparsely wound primary winding formed by winding a primary wire at a predetermined interval, and stably maintains the winding width in the axial direction of the primary winding. I'm doing some ingenuity.
Specifically, the primary coil of the present invention includes a primary winding formed by forming a second layer winding portion on the outer peripheral side of the first layer winding portion, and the first layer winding portion and the second layer winding portion are provided. The wire portion is wound with a winding pitch larger than the outer diameter of the primary electric wire (which means the outer diameter of the primary electric wire itself), thereby forming a predetermined interval between the primary electric wires. It is formed in a sparsely wound state.
In addition, the outer peripheral protrusion is formed on the outer peripheral surface of the primary spool, and the winding end portion in the first-layer winding portion is locked to the outer peripheral protrusion.

Therefore, even when the primary winding wound on the outer peripheral surface of the primary spool is pulled toward one side in the axial direction of the primary spool, the winding end portion in the first winding portion is positioned in the axial direction of the primary spool. Misalignment is prevented. For example, when the ignition coil is assembled, when the primary coil is inserted and disposed in a cylindrical part having a cylindrical cross-sectional shape, the primary winding is pulled toward the one side in the axial direction by the cylindrical part. Even at this time, it is possible to prevent the winding end portion in the first-layer winding portion from being displaced in the axial direction of the primary spool.
Thereby, it can prevent that the winding width in the axial direction of the primary winding provided with the 1st layer winding part and the 2nd layer winding part becomes small.
Therefore, according to the ignition coil of the present invention, the winding width in the axial direction of the primary winding in the primary coil can be stably maintained.

According to a second aspect of the present invention, there is provided an ignition coil manufacturing method including a primary coil and a secondary coil arranged concentrically.
A primary wire having an insulating coating is wound a plurality of times from one axial direction side of the primary spool having a cylindrical cross-sectional shape toward the other axial direction side to form a first winding portion, and then the first winding layer On the outer peripheral side of the part, the primary wire is wound a plurality of times from the other axial side of the primary spool to the one axial side to form a second layer winding part to produce the primary coil. Hitting
The first-layer winding portion and the second-layer winding portion are formed in a state where the winding pitch of the primary wire is larger than the outer diameter of the primary wire, and the other axial side of the first-layer winding portion The winding end portion located at the outer peripheral surface of the primary spool is engaged with the outer peripheral protrusion, and then the second-layer winding portion is formed. (Claim 5).

In the ignition coil manufacturing method of the present invention, a primary coil that can stably maintain the winding width in the axial direction of the primary winding can be produced.
Specifically, in the present invention, the first-layer winding portion and the second-layer winding portion are wound at a predetermined pitch between the primary wires by winding with a winding pitch larger than the outer diameter of the primary wire. Are formed in a loosely wound state. And the 2nd layer winding part is formed in the state where the above-mentioned volume termination part in the 1st layer winding part was locked to the perimeter projection part formed in the above-mentioned primary spool.

In the primary coil thus manufactured, even when the primary winding wound on the outer peripheral surface of the primary spool is pulled toward one side in the axial direction of the primary spool, the winding end portion in the first winding portion is the primary winding. It is possible to prevent displacement in the axial direction of the spool.
Therefore, according to the method for manufacturing an ignition coil of the present invention, a primary coil that can stably maintain the winding width in the axial direction of the primary winding in the primary coil can be easily manufactured.

A preferred embodiment in the first and second inventions described above will be described.
In the first and second inventions, it is preferable that the outer peripheral projection is integrally formed with the primary spool. In this case, the outer peripheral protrusion can be formed simultaneously with the formation of the primary spool, and the outer peripheral protrusion can be easily formed.
In the first invention, the outer peripheral projection can be provided on the primary spool after the primary spool is molded. Further, the outer peripheral projection can also be provided on the primary spool so as to lock the winding end portion in the first winding portion of the primary winding after the primary winding is wound around the primary spool.

In the first aspect of the invention, it is preferable that the winding pitch of the primary electric wire in the second layer winding portion is larger than the winding pitch of the primary electric wire in the first layer winding portion. In the second aspect of the invention, it is preferable that the winding pitch of the primary wire in the second layer winding portion is larger than the winding pitch of the primary wire in the first layer winding portion. ).
In this case, the interval between the primary wires in the second layer winding portion is larger than the interval between the primary wires in the first layer winding portion, and the first layer winding portion and the second layer winding. It is possible to prevent the primary winding from being collapsed by the portion. Therefore, the winding state of the primary winding can be stabilized.

In the first aspect of the invention, the outer peripheral projection is formed on a part of the outer peripheral surface of the primary spool in the circumferential direction, and has a long and narrow shape in a direction perpendicular to the axial direction of the primary spool. It is preferable to have (claim 3).
In this case, it is easy to lock the winding end portion of the first-layer winding portion to the outer peripheral projection. In addition, the locked state of the winding end portion with respect to the outer peripheral projection portion can be stably maintained.

Further, it is preferable that a plurality of the outer peripheral projections are formed side by side in the circumferential direction on the outer peripheral surface of the primary spool.
In this case, the winding end portion of the first-layer winding portion can be locked to any one of the plurality of outer peripheral protrusions, and this locking can be performed more easily.

Embodiments of the ignition coil and the manufacturing method thereof according to the present invention will be described below with reference to the drawings.
As shown in FIGS. 1 to 3, the ignition coil 1 of this example includes a primary coil 2 and a secondary coil 5 arranged concentrically, and is used by being inserted into a plug hole 81 in an engine case 8. It is a stick type. And in the ignition coil 1 of this example, the device for maintaining stably the winding width W in the axial direction D of the primary winding 4 in the primary coil 2 is performed.

  As shown in FIGS. 1 and 2, the primary coil 2 includes a primary winding 3 in which a primary spool 3 having a cylindrical cross-sectional shape and a primary electric wire 40 having an insulating coating are wound around an outer peripheral surface 31 of the primary spool 3 a plurality of times. 4 is provided. The primary winding 4 includes a first-layer winding portion 41 formed by winding the primary wire 40 a plurality of times from the one axial side D1 of the primary spool 3 toward the other axial side D2, and On the outer peripheral side, it is provided with a second layer winding portion 42 formed by winding the primary wire 40 a plurality of times from the other axial side D2 to the one axial direction D1.

Further, the first-layer winding portion 41 and the second-layer winding portion 42 are in a loosely wound state in which the winding pitches P1 and P2 of the primary wire 40 are larger than the outer diameter A of the primary wire 40. The first winding portion 41 has a winding end portion 411 located on the other axial side D2 thereof engaged with an outer peripheral protrusion 32 formed protruding from the outer peripheral surface 31 of the primary spool 3.
Here, the winding pitches P <b> 1 and P <b> 2 are intervals between the central axes of the primary electric wires 40 wound around the outer peripheral surface 31 of the primary spool 3, and the winding pitch P <b> 1 is larger than the outer diameter A of the primary electric wires 40. , P2 is large, so that a predetermined gap 45 is formed between the primary electric wires 40.

Hereinafter, the ignition coil 1 of this example will be described in detail with reference to FIGS.
The ignition coil 1 in this example is a CDI (capacitor-discharged ignition system) ignition coil 1 and supplies the primary coil 2 with the electric charge accumulated in a capacitor arranged in the power supply circuit of the igniter 712. To generate a spark. And the primary coil 2 does not need to make the inductance so large, and forms the primary winding 4 of the said sparsely wound state.

As shown in FIGS. 1 and 2, the primary spool 3 is formed from a synthetic resin material.
The primary spool 3 has a locking portion 33 for locking the lead wire 43 drawn from both ends of the primary winding 4 at the end on the one axial side D1 thereof.
The primary winding 4 has a pair of lead wires 43 locked by a locking portion 33 at the end of the primary spool 3 on the one axial side D1, and the end of the primary spool 3 on the other axial side D2 , The winding end portion 411 of the first-layer winding portion 41 is locked by the outer peripheral projection portion 32. Further, the outer peripheral projection 32 of this example is integrally formed with the primary spool 3.

As shown in FIG. 1, in the primary winding 4, the winding pitch P <b> 2 of the second-layer winding portion 42 is larger than the winding pitch P <b> 1 of the first-layer winding portion 41. Thereby, the gap 45 between the primary electric wires 40 in the second layer winding portion 42 is larger than the gap 45 between the primary electric wires 40 in the first layer winding portion 41, and the first layer winding portion The primary winding 4 is less likely to collapse due to the 41 and the second layer winding portion 42.
Further, the winding pitch P <b> 1 of the primary wire 40 in the first-layer winding portion 41 of this example is 2 to 4 times the outer diameter A of the primary wire 40. A gap 45 larger than the outer diameter A of the primary wire 40 is formed between the primary wires 40 in the first-layer winding portion 41. Further, the winding pitch P2 of the primary wire 40 in the second layer winding portion 42 of this example is twice or more the winding pitch P1 of the primary wire 40 in the first layer winding portion 41.

As shown in FIGS. 1 and 2, the outer peripheral projection 32 of the primary spool 3 of this example is formed to protrude radially outward from the outer peripheral surface 31 of the primary spool 3. The outer peripheral projection 32 is formed in a part of the outer peripheral surface 31 of the primary spool 3 in the circumferential direction R, and has a long and narrow shape in a direction perpendicular to the axial direction D of the primary spool 3. Further, the outer peripheral projection 32 of this example is formed at one location of the primary spool 3.
Further, the outer peripheral projection 32 is formed at the final design position of the primary wire 40 in the first layer winding 41.

  Moreover, the formation length in the direction orthogonal to the said axial direction D of the outer periphery protrusion part 32 can be changed suitably. For example, as shown in FIG. 2, the outer circumferential protrusion 32 has a constant protruding height from the outer circumferential surface 31 in a portion of the outer circumferential surface 31 of the primary spool 3 that is less than a half circumference (for example, about 45 °, 90 °, etc.) Can be formed. In addition, the outer peripheral projection part 32 of this example was formed in the range of about 90 ° in the circumferential direction R of the outer peripheral surface 31 of the primary spool 3.

Further, as shown in FIG. 4, the outer peripheral protrusion 32 has a constant protrusion height from the outer peripheral surface 31 in a portion (for example, about 180 °, 270 °, etc.) of more than half of the outer peripheral surface 31 of the primary spool 3. It can also be formed.
Further, as shown in FIG. 5, the outer peripheral protrusion 32 can be formed to protrude from the outer peripheral surface 31 of the primary spool 3 toward one side in the circumferential direction R.

Also, a plurality of outer peripheral projections 32 can be formed side by side in the circumferential direction R on the outer peripheral surface 31 of the primary spool 3. For example, as shown in FIG. 6, the outer circumferential protrusion 32 can be formed at two equal intervals in the circumferential direction R of the outer circumferential surface 31 of the primary spool 3. Further, for example, as shown in FIG. 7, the outer peripheral protrusions 32 can be formed at four equal intervals in the circumferential direction R of the outer peripheral surface 31 of the primary spool 3.
As described above, when a plurality of outer peripheral projections 32 are formed in the circumferential direction R, the winding terminal portion 411 in the first-layer winding portion 41 is set to any one of the plurality of outer peripheral projections 32. 32 can be locked, and this locking can be easily performed.

  As shown in FIG. 3, the secondary coil 5 of this example is formed by winding a secondary spool 51 having a cylindrical cross section and a secondary wire having an insulating coating around the outer peripheral surface 31 of the secondary spool 51 a plurality of times. The secondary winding 52 is provided. The secondary wire constituting the secondary winding 52 has a smaller outer diameter than the primary wire 40 constituting the primary winding 4, and the secondary winding 52 is more than the number of turns of the primary wire 40 in the primary winding 4. A secondary wire is wound by the number of windings.

  The ignition coil 1 includes a cylindrical portion 11 having a primary coil 2 and a secondary coil 5, an igniter head 71 disposed at one end D 1 in the axial direction of the cylindrical portion 11, and a shaft of the cylindrical portion 11. And a plug mounting portion 72 disposed at the end of the other direction side D2. The cylindrical portion 11 and the igniter head 71 are filled with an insulating resin such as an epoxy resin.

As shown in FIG. 3, the primary coil 2 and the secondary coil 5 are disposed in a resin coil case 63. A central core 61 made of a soft magnetic material is disposed on the inner peripheral side of the primary coil 2 and the secondary coil 5, and a soft magnetic material is provided on the outer peripheral side of the primary coil 2 and the secondary coil 5. An outer peripheral core 62 is disposed.
The secondary coil 5 is inserted into the inner peripheral side of the primary coil 2, and the central core 61 is inserted into the inner peripheral side of the secondary coil 5. The primary coil 2 is inserted into the inner peripheral side of the coil case 63, and the coil case 63 is inserted into the inner peripheral side of the outer peripheral core 62.

As shown in the figure, the igniter head 71 includes an igniter 712 having a power supply circuit for energizing the primary winding 4 of the primary coil 2 and a resin igniter case in which the igniter 712 is disposed. Part 711.
The plug attachment portion 72 has a rubber plug cap 721 for attaching the spark plug 75. The plug cap 721 is held by a cap holding portion 631 that extends from the other axial side D2 of the coil case 63. A coil spring 723 that contacts the head of the spark plug 75 is disposed in the cap holding portion 631, and this coil spring 723 is connected to the secondary winding 52 of the secondary coil 5 via the high-voltage terminal 722. It is electrically connected to the high voltage side end.

  When a pulse-like spark generation signal is transmitted from the engine control unit (ECU) to the power supply circuit of the igniter 712, a switching element or the like in the power supply circuit operates, and the primary coil 4 instantaneously Thus, a current flows and a magnetic field passing through the central core 61 and the outer core 62 is formed. Along with the formation and disappearance of this magnetic field, an induction magnetic field passing through the central core 61 and the outer peripheral core 62 is formed in a direction opposite to the magnetic field formation direction. Then, due to the formation of the induction magnetic field, an induced electromotive force (counterelectromotive force) is generated in the secondary winding 52 of the secondary coil 5, and a spark can be generated from the spark plug 75 attached to the ignition coil 1.

Next, a method for manufacturing the ignition coil 1 having the primary coil 2 will be described.
In the manufacturing method of the ignition coil 1 of this example, the device for producing the primary coil 2 is devised.
That is, in producing the primary coil 2, the primary spool 3 is first formed. At the time of this molding, the outer peripheral protrusion 32 is formed on the outer peripheral surface 31 of the primary spool 3, and a pair of primary windings 4 in the primary winding 4 are formed at the end of the axial direction one side D 1 of the primary spool 3. A locking portion 33 for locking the lead wire 43 is also formed.

Next, as shown in FIG. 9, the primary spool 3 is set on a rotating device (not shown), and the primary wire 40 is supplied to the outer peripheral surface 31 of the primary spool 3 from a wire supply portion (not shown) in the wire supply device. The primary wire 3 is wound by rotating the primary spool 3 with a rotating device.
At this time, the electric wire supply unit is moved toward the other axial side D2 of the primary spool 3 at a predetermined feed speed. Then, the primary electric wire 40 is wound from the one axial side D1 of the primary spool 3 toward the other axial side D2, and the first layer winding portion 41 is formed.
Moreover, in order to form the loosely wound first layer winding portion 41, the feed speed of the wire supply portion is set so that the winding pitch P <b> 1 of the primary wire 40 is larger than the outer diameter A of the primary wire 40.

Next, when the primary wire 40 is wound through the position where the outer circumferential protrusion 32 of the primary spool 3 is formed in the axial direction, the moving direction of the wire supply portion is reversed, and the wire supply portion is moved to one side in the axial direction of the primary spool 3. Move toward D1. At this time, the primary electric wire 40 supplied from the electric wire supply unit to the primary spool 3 becomes a winding end portion 411 in the first-layer winding portion 41 and is locked to the outer peripheral projection portion 32.
At this time, the feed rate of the wire supply unit is set faster than the feed rate when forming the first-layer winding portion 41.

Then, the primary electric wire 40 is wound from the other axial side D2 of the primary spool 3 toward the one axial side D1, and the second layer winding portion 42 is formed. Further, the primary wire 40 in the second layer winding portion 42 is formed in a state in which the winding pitch P2 is larger than the winding pitch P1 of the primary wire 40 in the first layer winding portion 41.
In this way, the primary coil 2 that can stably maintain the winding width W in the axial direction D of the primary winding 4 can be manufactured.

In addition, components (secondary coil 5 etc.) other than the primary coil 2 in the ignition coil 1 can be produced by a method similar to the conventional method.
The primary electric wire 40 is wound by moving the electric wire supply unit in the electric wire supply device in the axial direction D while rotating the outer periphery of the primary spool 3 instead of rotating the primary spool 3 by the rotating device. Can also be performed.

  As described above, the cap holding portion 631 is formed on the other axial side D <b> 2 of the coil case 63. As shown in FIG. 1, when the ignition coil 1 is assembled, the primary coil 2 is inserted into the coil case 63 from one axial side D <b> 1 of the coil case 63. At this time, when the primary winding 4 in the primary coil 2 comes into contact with the coil case 63 as a cylindrical part, the primary winding 4 is pulled toward the one side D1 in the axial direction.

On the other hand, in the primary coil 2 of this example, the winding end portion 411 in the first-layer winding portion 41 is locked to the outer peripheral projection portion 32 in the primary spool 3, so that the winding end portion 411 becomes the primary spool. 3 can be prevented from being displaced in the axial direction D.
Thereby, it can prevent that the winding width W in the axial direction D of the primary winding 4 provided with the 1st layer winding part 41 and the 2nd layer winding part 42 becomes small.

  Moreover, the ignition coil 1 of this example is a small diameter whose outer diameter of the cylindrical part 11 is (phi) 16-24mm. When the diameter of the ignition coil 1 is reduced, the gap between the primary coil 2 and the cylindrical part (in this example, the coil case 63) disposed on the outer peripheral side is narrowed. Therefore, when the ignition coil 1 is assembled, the primary winding 4 in the primary coil 2 and the cylindrical part are in contact with each other, and the winding width W in the axial direction D of the primary winding 4 tends to be small. By forming the outer peripheral projection 32, the winding width W in the axial direction D of the primary winding 4 can be stably maintained.

  Therefore, according to the ignition coil 1 of this example, the winding width W in the axial direction D of the primary winding 4 in the primary coil 2 can be stably maintained.

The ignition coil 1 can have various structures other than the structure shown in the first embodiment.
For example, the primary coil 2 can be inserted into the secondary coil 5. In this case, when the primary coil 2 is inserted and arranged in the secondary coil 5 as the cylindrical part, it is possible to prevent the displacement of the winding end portion 411 in the first-layer winding portion 41.
In addition, the primary coil 2 can be inserted into the outer core 62. In this case, when the primary coil 2 is inserted and arranged in the outer peripheral core 62 as the cylindrical part, it is possible to prevent the displacement of the winding end portion 411 in the first-layer winding portion 41.
Further, the primary coil 2 can also be inserted and disposed in an insulating cylinder made of synthetic resin disposed on the inner peripheral side of the outer peripheral core 62. In this case, when the primary coil 2 is inserted and arranged in the insulating cylinder as the cylindrical part, it is possible to prevent the displacement of the winding end portion 411 in the first-layer winding portion 41.

  Further, as shown in FIG. 9, in the primary spool 3, an auxiliary outer peripheral protrusion 34 that protrudes from the outer peripheral surface 31 of the primary spool 3 is formed between the outer peripheral protrusion 32 and the locking portion 33. You can also In this case, the first-layer winding portion 41 can be prevented from being displaced in the axial direction D of the primary spool 3 at the intermediate position in the axial direction D.

Explanatory drawing which shows the primary coil in an Example. Cross-sectional explanatory drawing which shows the primary coil in an Example. Cross-sectional explanatory drawing which shows the ignition coil in an Example. Sectional explanatory drawing which shows the other primary coil in an Example. Sectional explanatory drawing which shows the other primary coil in an Example. Sectional explanatory drawing which shows the other primary coil in an Example. Sectional explanatory drawing which shows the other primary coil in an Example. Explanatory drawing which shows the state which has wound the primary wire around the outer peripheral surface of the primary spool in an Example. Explanatory drawing which shows the other primary coil in an Example. Explanatory drawing which shows the primary coil in a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ignition coil 2 Primary coil 3 Primary spool 31 Outer peripheral surface 32 Outer peripheral projection part 4 Primary winding 40 Primary electric wire 41 First layer winding part 411 Winding end part 42 Second layer winding part 5 Secondary coil D1 Axial direction one side D2 Axial direction other side R Circumferential direction A Outer diameter P1, P2 Winding pitch W Winding width

Claims (6)

In an ignition coil having a primary coil and a secondary coil arranged concentrically,
The primary coil includes a primary spool having a cylindrical cross-sectional shape, and a primary winding formed by winding a primary wire having an insulating coating around the outer peripheral surface of the primary spool a plurality of times.
The primary winding is a first-layer winding portion formed by winding the primary electric wire a plurality of times from one axial direction side of the primary spool to the other axial direction side, and an outer peripheral side of the first-layer winding portion. A second-layer winding portion formed by winding the primary electric wire a plurality of times from the other axial side toward the one axial side, the second-layer winding portion and the first-layer winding portion Is a loosely wound state in which the winding pitch of the primary wire is larger than the outer diameter of the primary wire,
The ignition coil, wherein the first winding portion has a winding end portion located on the other side in the axial direction engaged with an outer peripheral protrusion formed to protrude from the outer peripheral surface of the primary spool.   2. The ignition coil according to claim 1, wherein a winding pitch of the primary electric wire in the second-layer winding portion is larger than a winding pitch of the primary electric wire in the first-layer winding portion.   3. The outer peripheral projection according to claim 1, wherein the outer peripheral protrusion is formed in a part of the outer peripheral surface of the primary spool in a circumferential direction and has a long and narrow shape in a direction perpendicular to the axial direction of the primary spool. An ignition coil characterized by that.   4. The ignition coil according to claim 3, wherein a plurality of the outer peripheral protrusions are arranged side by side in the circumferential direction on the outer peripheral surface of the primary spool. In the method of manufacturing an ignition coil having a primary coil and a secondary coil arranged concentrically,
A primary wire having an insulating coating is wound a plurality of times from one axial direction side of the primary spool having a cylindrical cross-sectional shape toward the other axial direction side to form a first winding portion, and then the first winding layer On the outer peripheral side of the part, the primary wire is wound a plurality of times from the other side in the axial direction of the primary spool to the one side in the axial direction to form a second-layer winding part, and the primary coil is manufactured. In doing so,
The first-layer winding portion and the second-layer winding portion are formed in a state where the winding pitch of the primary wire is larger than the outer diameter of the primary wire, and the other axial side of the first-layer winding portion A method for producing an ignition coil comprising: forming a second winding portion after engaging a winding terminal portion positioned at a peripheral protrusion portion protruding from an outer peripheral surface of the primary spool.   6. The method for manufacturing an ignition coil according to claim 5, wherein a winding pitch of the primary electric wire in the second layer winding portion is larger than a winding pitch of the primary electric wire in the first layer winding portion.

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