JPH0922825A - Ignition coil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the influence of heat and vibration from an internal engine and to save space around the internal engine by covering a secondary coil winding floor where a secondary coil is formed with an insulating material. SOLUTION: A primary coil 13 is formed by winding an enamel wire 13a around a primary coil winding floor 13 formed from one edge to the other of a cable-shaped magnetic core 11 with a specific length which is a ferromagnetic body. Also, a secondary coil 15 is formed by winding an enamel wire 15a around a secondary winding floor 14 which is formed over the entire region on the primary coil winding floor 12 where the primary coil 13 is formed. Then, an insulation layer 16 is formed over the entire region on the secondary coil winding floor 14 where the secondary coil 15 is formed, an iron foil 17 is wound around the outer periphery of the insulation layer 16, and a sheath 18 is formed on the iron foil 17. Therefore, since an ignition coil 10 is formed entirely in a line as in a normal cable, thus reducing installation space and eliminating the need for directly placing it to an internal engine.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ignition coil for an independent ignition system used in an internal combustion engine.

[0002]

2. Description of the Related Art As shown in FIG. 11, an ignition coil of this type includes a magnetic core 51 in which electromagnetic steel sheets are laminated, a primary coil bobbin 52 mounted on the magnetic core 51, and an enamel on the primary coil bobbin 52. A primary coil 53 formed by winding a wire, a secondary coil bobbin 54 fitted on the outside of the primary coil bobbin 52 in which the primary coil 53 is formed, and an enamel wire wound on the secondary coil bobbin 54. Ignition coil body 50 having a secondary coil 55 formed by turning, and this ignition coil body 50
And a case 60 for accommodating the secondary coil 55 and a primary connector portion 61 having a connection terminal 62 to which the primary coil 53 is connected, and a connection to which the secondary coil 55 is connected. A secondary connector portion 63 having terminals 64 is formed.

A thermosetting resin such as an epoxy resin is filled in the space inside the case 60 in which the ignition coil body 50 is housed.
The secondary coil 53 and the secondary coil 55 are impregnated and fixed, and at the same time, the insulating property of withstanding the high output voltage of the secondary coil 55 is ensured.

In the ignition coil constructed as described above, the case 60 is directly fixed to the internal combustion engine with the secondary connector portion 63 fitted and inserted in the plug hole of the internal combustion engine.
The primary connector portion 61 is connected to a battery via a cable, and the secondary connector portion 63 is connected to an ignition plug via a connection terminal in the plug hole.

[0005]

By the way, as described above, in the ignition coil in which the primary coil bobbin 52 and the secondary coil bobbin 54 are assembled to the magnetic core 51 in which electromagnetic steel sheets are laminated, the ignition coil main body 50 itself is bulky. , It is necessary to secure some installation space around the internal combustion engine to be installed.

Further, since such an ignition coil has a large number of constituent parts and the shapes of the respective parts are complicated, the cost for manufacturing a die for manufacturing these parts is high, and these parts are required for the ignition coil. Since it depends on the shape of the internal combustion engine in which it is installed, it is not versatile and different parts must be prepared according to the shape of the internal combustion engine.
This is a factor that increases the product cost of the ignition coil.

Further, as described above, such an ignition coil has a case 60 in which the ignition coil main body 50 is housed.
Since it is directly attached to the internal combustion engine, it is directly affected by heat and vibration from the internal combustion engine, which is a factor of shortening the life of the ignition coil.

Therefore, an object of the present invention is to provide an ignition coil which is less susceptible to heat and vibration from the internal combustion engine, and which can save space around the internal combustion engine and reduce the product cost. .

[0009]

In order to solve the above problems, the present invention provides a flexible cable-like magnetic core formed by bundling wires formed of a ferromagnetic material, and an insulating material for the magnetic core. A primary coil winding bed formed by extrusion coating, a primary coil formed by winding an electric wire on the primary coil winding bed, and a primary coil formed with the primary coil A secondary coil winding bed formed by extrusion coating an insulating material on the winding bed, a secondary coil formed by winding an electric wire around the secondary coil winding bed, and the secondary coil are formed. And an insulating layer formed by coating an insulating material on the secondary coil winding bed.

The outer peripheral surface of the insulating layer is covered with a magnetic shield layer made of a ferromagnetic material such as iron foil, cobalt or amorphous alloy, and the outside of the magnetic shield layer is made of an insulating material. The magnetic core may be formed by twisting the bundled wires or compressing them in the radial direction.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, the ignition coil 10 includes a cable-shaped magnetic core 11 having a predetermined length, which is a ferromagnetic body, and a primary coil winding bed formed from one end to the other end of the magnetic core 11. 12 and the primary coil winding floor 12
A primary coil 13 formed by winding an enamel wire 13a on the inner surface of the primary coil 13 and a secondary coil winding floor formed over the entire area of the primary coil winding floor 12 on which the primary coil 13 is formed. 14, a secondary coil 15 formed by winding an enamel wire 15a around the secondary coil winding bed 14, and the entire area of the secondary coil winding bed 14 on which the secondary coil 15 is formed. The insulating layer 16 formed across and the iron foil 1 wrapped around the outer periphery of the insulating layer 16
7 and a sheath 18 that covers the iron foil 17.

The magnetic core 11 is an electromagnetic soft iron rod (JISC2
503 SUYB1) is φ0.3-2.
A wire rod 11a drawn into 5 mm is bundled and twisted from several to several tens, and then compressed in a radial direction by passing through a cemented carbide or diamond die and has a certain flexibility. Therefore, it can be bent freely.

The primary coil winding bed 12 includes the magnetic core 11
It is formed by extrusion-coating an insulating organic material with a thickness of 0.1 to 1.0 mm, and examples of the insulating organic material include fluororubber, ethylene-propylene rubber (EPDM, EPM), and silicone rubber. It is suitable to use a plastic material such as cross-linked polyethylene that can be extruded, has an appropriately high heat resistant temperature, has a proven record as a cable insulating material, and has flexibility.

The secondary coil winding bed 14 has an insulating organic material similar to that of the primary coil winding bed 12 having a thickness of 0.
The insulating layer 16 is formed by extrusion coating with a thickness of 3 to 2.0 mm, and the insulating layer 16 is formed by extrusion coating an insulating organic material similar to that of the primary coil winding bed 12 with a thickness of about 1 to 4 mm. Has been done.

As the insulating organic material forming the secondary coil winding bed 14, it is important that it has heat resistance since Joule heat generation from the primary coil 13 is large. On the other hand, as the insulating organic material forming the insulating layer 16, although the heat generated from the secondary coil is small, since it is installed in the vicinity of the internal combustion engine, the ambient temperature is high and the heat resistance of about 200 ° C. is also required. Become. The electrical characteristics required for the insulating organic material forming the secondary coil winding bed 14 and the insulating layer 16 are a specific resistance of 10 ¹² Ω · cm.
As described above, the withstand voltage is required to be 20 KV / mm or more, and it is also an important condition to have a certain flexibility like the primary coil winding floor 12.

The enameled wire 13a which is the winding of the primary coil 13 has a diameter of 0.1 to 0.6 mm, and the enameled wire 1 which is the winding of the secondary coil 15 is used.
5a has a diameter of 0.03 to 0.1 mm.

As the material of the sheath 18, silicone rubber, ethylene-propylene rubber (EPDM,
EPM), acrylic rubber, etc. are suitable.

The ignition coil 10 is coated with the iron foil 17 as described above. The reason why the iron foil 17 is provided is that since the coil is a noise source, the coil is provided with a shielding function. This is because the magnetic field generated by the magnetic field is adjusted, the withstand voltage with respect to the outside is improved, and the electrostatic capacity is increased by grounding the shield to increase the ignition energy. In addition to the iron foil 17, a ferromagnetic material such as cobalt or amorphous alloy may be coated.

Ignition coil 10 constructed as described above
Is manufactured as follows. First, in the first step, the electromagnetic soft iron rod is Φ by a wire drawing machine (not shown).
Since the plurality of wire rods 11a drawn to 0.3 to 2.5 are continuously supplied, as shown in FIG. 2, after the plurality of wire rods 11a are bundled by the binding device 31 and twisted,
It is compressed in the radial direction by passing it through a cemented carbide or diamond die 32, and is sent to the next step as a continuous flexible cable-shaped magnetic core 11.

In the second step, as shown in FIG. 3, the first magnetic core 11 is continuously sent out in this manner.
The organic coil extrusion device 33 continuously extrudes and coats an insulating organic material such as fluororubber to cover the primary coil winding bed 12
Are formed and sent to the next step.

In the third step, on the primary coil winding bed 12 formed on the magnetic core 11 thus continuous, as shown in FIG. 4, the enamel wire is wound by the primary coil winding device 34. By winding 13a laterally, the primary coil 13 is formed on each primary coil winding bed 12 and sent to the next step.

In the fourth step, as shown in FIG. 5, on the respective primary coil winding beds 12 on which the primary coils 13 are formed in this manner, a fluororubber or the like is produced by the second organic material extrusion device 35. The insulative organic material is continuously extrusion-coated to form the secondary coil winding bed 14 in sequence and is sent to the next step.

In the fifth step, the enamel wire 15a is horizontally wound on the secondary coil winding bed 14 thus formed by the secondary coil winding device 36 as shown in FIG. The secondary coil 15 is formed on the secondary coil winding bed 14 and sent to the next step.

In the sixth step, as shown in FIG. 7, fluororubber or the like is applied to each of the secondary coil winding beds 14 thus formed with the secondary coil 15 by the third organic material extruding device 37. The insulating organic material is continuously extrusion-coated to form the insulating layer 16, and the insulating layer 16 is sent to the next step.

In the seventh step, as shown in FIG. 8, after the iron foil 17 is wound on the insulating layer 16 by the iron foil winding device 38, the iron foil 17 is wound on the iron foil 17 by the fourth organic material extrusion device 39. An insulating organic material such as silicone rubber is continuously extrusion-coated to form a sheath 18, which is then sent to the next step.

In the final eighth step, as shown in FIG.
By cutting into a predetermined length, the cable-shaped ignition coil 10 having a predetermined length is sequentially manufactured.

In this embodiment, a plurality of wire rods 11
The magnetic core 11 is formed by bundling a and twisting them together, and then compressing them in the radial direction. The magnetic core 11 is formed by simply twisting a plurality of wire rods 11a, or without twisting. It may be just compressed in the radial direction.

In this embodiment, the insulating layer 16 is formed by extrusion-coating an insulating organic material such as fluororubber, but the present invention is not limited to this. For example, the insulating layer 16 is formed of an insulating material. It can also be formed by covering the above tube, winding an insulating tape, applying a liquid resin, or molding with an insulating resin.

In this embodiment, a magnetic shield layer made of a ferromagnetic material such as iron foil 17 is provided outside the insulating layer 16, but such a magnetic shield layer is not always required. Absent.

Ignition coil 10 manufactured in this way
Is a flexible cable and can be handled in the same manner as a normal high tension cord, and is specifically used as follows.

As shown in FIG. 10, one end of a connection terminal 24 accommodated in the plug hole 21 is connected to the terminal 23 of the spark plug 22 installed in the plug hole 21 of the internal combustion engine 20. The other end side of the connection terminal 24 is supported by a fixing member 25 fixed to the internal combustion engine 20, and the ignition coil 10 has the secondary coil 15 connected to the other end side of the connection terminal 24 at one end side thereof. And the primary coil 13 on the other end side.
Are connected to control circuits such as the power transistor 26, the igniter 27, and the electronic control unit (ECU) 28.

As described above, since the ignition coil 10 is in the form of a flexible cable, the installation space for the ignition coil 10 is smaller than the conventional one, and it is not necessary to directly mount the ignition coil 10 on the internal combustion engine 20 as described above. Since it is not necessary to change the shape, structure, etc. of the ignition coil according to the shape of the internal combustion engine 20, versatility is enhanced.

Further, since the ignition coil 10 is made into a cable shape to increase the distance from the internal combustion engine 20, it is less susceptible to heat and vibration from the internal combustion engine 20, and the life of the ignition coil 10 itself is extended. Since it is not necessary to make the insulating layer 16 and the sheath 18 surrounding the secondary coil 13 thicker than necessary, the capacitance increases, and the ignition energy increases accordingly.

Also, since the primary coil bobbin 12 and the secondary coil bobbin 14 corresponding to the conventional primary coil bobbin and secondary coil bobbin are formed by extrusion coating of an insulating organic material, the number of parts is small. In addition, since the mold is not used, it is possible to reduce the product cost by reducing the mold cost.

Further, in the above-mentioned manufacturing method, since extrusion molding is frequently used, it is possible to use the extrusion coating device used for manufacturing the coated electric wire, and it is possible to reduce the equipment cost.

[0036]

As described above, the entire ignition coil of the present invention is formed in the same linear shape as that of a normal cable, so that the installation space can be reduced.
Moreover, since it does not need to be directly attached to the internal combustion engine, it is not affected by the shape of the internal combustion engine, the versatility is increased, and heat and vibration from the internal combustion engine are not directly received.
This has the effect of extending the product life.

Also, since the number of constituent parts is small and the primary coil winding bed and the secondary coil winding floor are formed by extrusion coating with an insulating material respectively, it is not necessary to use a mold for manufacturing the parts. The product cost can be reduced by reducing the die cost.

[Brief description of drawings]

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

FIG. 2 is a process chart showing a manufacturing method of the same.

FIG. 3 is a process drawing showing the manufacturing method of the above.

FIG. 4 is a process drawing showing the manufacturing method of the above.

FIG. 5 is a process drawing showing the manufacturing method of the above.

FIG. 6 is a process drawing showing the manufacturing method of the above.

FIG. 7 is a process drawing showing the manufacturing method of the above.

FIG. 8 is a process drawing showing the manufacturing method of the above.

FIG. 9 is a process drawing showing the manufacturing method of the above.

FIG. 10 is a schematic view showing a usage example of the above.

FIG. 11 is a sectional view showing a conventional example.

[Explanation of symbols]

 10 Ignition coil 11 Magnetic core 12 Primary coil winding bed 13 Primary coil 14 Secondary coil winding bed 15 Secondary coil 16 Insulating layer 17 Iron foil 18 Sheath 31 Bundling device 32 Carbide or diamond die 33 First organic material extrusion device 34 Primary coil winding device 35 Second organic material extruding device 36 Secondary coil winding device 37 Third organic material extruding device 38 Iron foil winding device 39 Cutting device

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location 9375-5E H01F 31/00 501E

Claims (5)

[Claims] 1. A flexible cable-shaped magnetic core formed by bundling wires made of a ferromagnetic material, and a primary coil winding bed formed by extrusion-coating the magnetic core with an insulating material. A primary coil formed by winding an electric wire on the primary coil winding bed, and a secondary formed by extrusion coating an insulating material on the primary coil winding bed on which the primary coil is formed. A coil winding bed, a secondary coil formed by winding an electric wire around the secondary coil winding bed, and an insulating material formed on the secondary coil winding bed on which the secondary coil is formed. Ignition coil with an insulated layer. 2. The ignition according to claim 1, wherein an outer peripheral surface of the insulating layer is covered with a magnetic shield layer formed of a ferromagnetic material, and an outer side of the magnetic shield layer is covered with a sheath formed of an insulating material. coil. 3. The ignition coil according to claim 2, wherein the magnetic shield layer is formed of iron foil, cobalt or an amorphous alloy. 4. The ignition coil according to claim 1, wherein the magnetic core is formed by twisting the bundled wires together. 5. The ignition coil according to claim 1, 2, 3 or 4, wherein the magnetic core is compressed in the radial direction.