JP2007329332A - Ignition coil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ignition coil where overlap of noise with a signal line of a sensor is effectively controlled when the signal line of the sensor is arranged at a periphery of a secondary coil. <P>SOLUTION: The ignition coil is provided with a connector which performs electrical connection with an external part at one end in an axial direction of a coil main body having a primary coil 2 and a secondary coil, and with a sparking plug generating sparks by the secondary coil at the other end part in the axial direction of the coil main body. The coil also has a sensor measuring a state amount in a gas column of an engine in the sparking plug. In the primary coil 2, a primary electric wire 211 is wound in the axial direction L for a plurality of times and is wound to a plurality of layers in a radial direction R so as to form a plurality of winding layers 21. A sensor signal line 751 is arranged between an inner winding layer 21A positioned on an inner side in a plurality of winding layers 21 and an outer winding layer 21B positioned outside the inner wiring layer 21A, and it is pulled out to the connector part. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an ignition coil for igniting combustion by generating a spark in a combustion chamber in an engine cylinder.

An ignition coil used by being installed in each cylinder of an engine such as a vehicle is inserted and arranged in a plug hole in a cylinder head, and sparks are generated from a spark plug attached to the ignition coil, thereby igniting combustion in each cylinder. Is going.
This ignition coil generates a sparking voltage in a spark plug by a primary coil that energizes in response to a switching signal from an ECU (electronic control unit) and an induced magnetic field that is generated when the energization of the primary coil is cut off. A secondary coil. Some ignition coils include a sensor for measuring a state quantity in a combustion chamber of an engine.

The signal line of the sensor needs to be pulled out from the periphery of the spark plug inserted and arranged in the plug hole to the connector portion arranged outside the plug hole.
However, in the stick type ignition coil that is used by inserting and arranging the primary coil and the secondary coil in the plug hole, the signal line drawn from the sensor is drawn to the connector part through the periphery of the secondary coil. Become. Therefore, in this case, noise may be superimposed on the signal line of the sensor due to the influence of the spark voltage (high voltage), the influence of the magnetism remaining after the occurrence of the spark, and the like.

For example, Patent Document 1 discloses a technique related to a spark plug with a built-in pressure sensor. And the extension position in the circumferential direction of the lead wire taken out from the pressure sensor can be easily aligned with a predetermined position (direction) of, for example, a knocking detection device, and the lead wire is damaged or disconnected. A technique for preventing the occurrence of the above is disclosed.
However, the technique of Patent Document 1 is applied to an ignition coil of a type in which a primary coil and a secondary coil are arranged outside a plug hole. Therefore, the device at the time of arrange | positioning the signal wire | line of a sensor through the periphery of a secondary coil is not made | formed.

JP 2002-246147 A

  The present invention has been made in view of such conventional problems, and effectively suppresses noise from being superimposed on the signal line of the sensor when the signal line of the sensor is arranged around the secondary coil. It is intended to provide an ignition coil that can.

The present invention includes a connector part for making an electrical connection with the outside at one end in the axial direction of a coil main body provided with a primary coil and a secondary coil, and at the other end in the axial direction of the coil main body. In an ignition coil comprising a spark plug for generating a spark by a secondary coil, and comprising a sensor for measuring a state quantity in a cylinder of the engine in the spark plug,
The primary coil is formed by winding a primary wire in the axial direction and winding it in a plurality of layers in the radial direction to form a plurality of winding layers,
The signal line of the sensor is disposed between the inner winding layer located inside the plurality of winding layers and the outer winding layer located outside the inner winding layer, and the connector portion (1).

The ignition coil of the present invention includes the above-described sensor, and has a structure that is not easily affected by noise when the signal line of this sensor is arranged through the periphery of the secondary coil.
That is, in the ignition coil according to the present invention, the signal line of the sensor is arranged between the inner winding layer and the outer winding layer in the primary coil and is drawn out to the connector portion. Thereby, the signal wire | line of a sensor can be covered with the inner side winding layer and outer side winding layer in a primary coil. Therefore, even if the sensor signal line is arranged around the secondary coil, noise is superimposed on the sensor signal line due to the influence of the spark voltage (high voltage), the influence of the magnetism remaining after the occurrence of the spark, etc. This can be effectively suppressed.

  Therefore, according to the ignition coil of the present invention, when the signal line of the sensor is arranged around the secondary coil, it is possible to effectively suppress the noise from being superimposed on the signal line of the sensor.

A preferred embodiment of the present invention described above will be described.
In the present invention, the signal line of the sensor can be arranged by being wound a plurality of times in the axial direction between the inner winding layer and the outer winding layer.
In this case, the sensor signal lines can be easily arranged, and the sensor signal lines can be stably arranged between the inner winding layer and the outer winding layer.

Further, the signal line of the sensor may be disposed along the axial direction between the inner winding layer and the outer winding layer.
In this case, the arrangement of the sensor signal lines is easy, and the length of the sensor signal lines can be shortened.

Further, an outer peripheral core made of a magnetic material is disposed on the outer peripheral side of the primary coil and the secondary coil, and the outer peripheral core is formed with a gap between its circumferential end faces, When the signal lines of the sensor are arranged along the axial direction, it is preferable to arrange the sensor signal lines along the axial direction by utilizing the space formed by the gap.
In this case, the signal line of the sensor can be arranged using the space formed by the gap between the outer peripheral cores, and the increase in the outer diameter of the ignition coil can be effectively suppressed.

The primary coil is formed with two winding layers, and the signal line of the sensor includes a first winding layer as the inner winding layer and two layers as the outer winding layer. It can arrange | position between eyeglass layers (Claim 5).
In this case, it is easy to form the primary coil, and it is also easy to arrange the sensor signal line between the inner winding layer and the outer winding layer.

The sensor may be a combustion pressure sensor that detects a combustion state in a cylinder of the engine.
In this case, it is possible to effectively suppress noise from being superimposed on the signal line of the combustion pressure sensor.
In addition to the combustion pressure sensor, the sensor detects a knock sensor that detects vibration (knocking) due to abnormal combustion of the engine, a plague sensor that detects a temperature due to abnormal combustion around the spark plug, and a temperature around the spark plug. A temperature sensor or a proximity sensor that detects a gap between the piston and the engine may be used.

Hereinafter, embodiments of the ignition coil according to the present invention will be described with reference to the drawings.
(Example 1)
As shown in FIG. 1 and FIG. 2, the ignition coil 1 of the present example is a connector portion 5 that is electrically connected to the outside at an axial end portion 111 of a coil body portion 11 that includes a primary coil 2 and a secondary coil 3. And a spark plug 7 for generating a spark by the secondary coil 3 at the other axial end 112 of the coil body 11. Further, the ignition coil 1 includes a sensor 75 for measuring a state quantity in a cylinder of the engine 8 in the spark plug 7.

  As shown in FIGS. 3 and 4, the primary coil 2 forms a plurality of winding layers 21 by winding the primary wire 211 in the axial direction L a plurality of times and in the radial direction R in a plurality of layers. It becomes. The sensor signal line 751 of the sensor 75 is between the inner winding layer 21A located inside the plurality of winding layers 21 and the outer winding layer 21B located outside the inner winding layer 21A. Arranged and pulled out to the connector portion 5.

Hereinafter, the ignition coil 1 of this example will be described in detail with reference to FIGS.
As shown in FIGS. 1 and 2, the ignition coil 1 of this example is of a stick type in which the coil body 11 is inserted and used in a plug hole 81 in an engine (cylinder head cover) 8. The connector part 5 is disposed outside the plug hole 81.
1 shows the ignition coil 1 in a state before the spark plug 7 is attached, and FIG. 2 shows the ignition coil 1 in a state where the spark plug 7 is attached.

As shown in FIG. 3, the primary coil 2 of this example is obtained by winding an insulating-coated primary electric wire 211 (copper wire in this example) in the axial direction L a plurality of times on the outer peripheral surface of a primary spool 22 made of a cylindrical resin. Become. Further, the primary electric wire 211 of this example is laminated and wound in two layers in the radial direction R, and the sensor signal line 751 includes a first winding layer 21A as the inner winding layer 21A and an outer winding. It is arranged between the second winding layer 21B as the layer 21B.
In addition, the winding start end portion 212 and the winding end end portion 213 of the primary electric wire 211 are positioned on one end L1 in the axial direction of the primary coil 2 (the arrangement side of the connector portion 5).

  As shown in FIG. 1, the secondary coil 3 of this example is formed by winding an insulating-coated secondary electric wire 31 on the outer peripheral surface of a secondary spool 32 made of a cylindrical resin with a greater number of turns than the primary electric wire 211. . In addition, the secondary coil 3 includes a plurality of inclined winding layers in which the secondary electric wire 31 having a diameter smaller than that of the primary electric wire 211 is wound in an inclined state so that the winding diameter is reduced toward the other axial end L2. A plurality of windings are made toward the other axial end L2.

  The secondary coil 3 and the secondary spool 32 are disposed on the inner peripheral side of the primary coil 2 and the primary spool 22, and a central core 41 made of a magnetic material is disposed on the inner peripheral side of the secondary spool 32. It is. The primary coil 2 and the primary spool 22 are arranged in a coil case 43 made of a cylindrical resin, and an outer peripheral core 42 made of a magnetic material is arranged on the outer peripheral side of the coil case 43.

Further, as shown in FIG. 4, the central core 41 is formed by laminating a plurality of flat electromagnetic steel plates (silicon steel plates in this example) having an insulating coating in a cross-sectional direction perpendicular to the axial direction L of the ignition coil 1. It becomes. The outer peripheral core 42 is formed by laminating a plurality of cylindrical electromagnetic steel plates (silicon steel plates in this example) formed with slits (gap) 421 in the axial direction L with an adhesive in the radial direction R. That is, the outer peripheral core 42 is formed by forming a gap 422 between the end surfaces 421 in the circumferential direction C.
The central core 41 and the outer core 42 can form a magnetic circuit that allows a magnetic flux generated by passing a current to the primary coil 2 to pass therethrough. Further, a stress relaxation tape 411 is wound around the outer periphery of the central core 41.

  As shown in FIG. 1, the connector unit 5 of this example is configured by disposing an igniter 52 for supplying power to the primary coil 2 in a connector case 51. The connector case 51 is formed with a disposing portion 511 for disposing the igniter 52 and a case fitting 512 for fitting the coil case 43 and the outer core 42.

In addition, the connector case 51 has a connection portion 53 formed by insert-molding a conductive pin 531 that is electrically connected to the conductive pin in the igniter 52 toward the outside in the radial direction R, and for attaching the ignition coil 1 to the engine 8. A flange portion 54 is formed.
The igniter 52 includes a power control circuit that uses a switching element that operates in response to a signal from an ECU (electronic control unit), a sensor amplifier that processes an information signal received from the sensor signal line 751, and the like.

As shown in FIG. 1, a plug base portion 6 is connected to the other axial end portion of the coil case 43 of this example, and a rubber plug cap 61 is attached to the plug base portion 6. . The plug cap 61 is formed with a plug fitting inlet 611 into which the lever portion 71 of the spark plug 7 is fitted.
Further, between the extension 321 formed at the other axial end of the secondary spool 32 and the plug base portion 6, the secondary conducting to the high voltage winding end of the secondary wire 31 in the secondary coil 3. A terminal (high voltage terminal) 62 is sandwiched, and a spring 63 that conducts to the secondary terminal 62 is disposed on the inner peripheral side of the plug base portion 6.

Further, as shown in FIG. 2, the spark plug 7 has the lever portion 71 fitted and disposed in the plug fitting inlet 611 of the plug cap 61 with the conduction terminal portion 72 in contact with the spring 63.
A gap in the ignition coil 1 surrounded by the coil case 43, the plug base portion 6, and the connector case 51 is filled with a thermosetting resin 15 such as an epoxy resin.

As shown in the figure, the spark plug 7 of the present example includes an insulator portion 71, a conduction terminal portion 72 formed at one end portion in the axial direction of the insulator portion 71, and from the insulator portion 71 toward the other end side L2 in the axial direction. It has a threaded portion 73 that extends and is screwed into the engine 8, and a pair of electrode portions 74 that are formed at the other axial end of the threaded portion 73. The pair of electrode portions 74 are disposed so as to protrude into the combustion chamber in the cylinder of the engine 8.
The sensor 75 provided in the spark plug 7 of this example is a combustion pressure sensor that detects the combustion state in the combustion chamber in the cylinder of the engine 8. From this sensor 75, a pair of positive and negative sensor signal lines 751 is drawn out.

As shown in FIG. 3, the sensor signal line 751 of this example is arranged by being wound a plurality of times in the axial direction L between the inner winding layer 21 </ b> A and the outer winding layer 21 </ b> B in the primary coil 2.
In forming the primary coil 2 of this example, the primary wire 211 is wound a plurality of times on the outer peripheral surface of the primary spool 22 from the one axial end side L1 to the other axial end side L2 to form an inner winding. A layer (first winding layer) 21A is formed. Next, the pair of sensor signal lines 751 is wound around the outer periphery of the inner winding layer 21A a plurality of times from the other axial end L2 to the first axial end L1. After that, the outer periphery of the pair of sensor signal lines 751 is continuously wound from the end of the primary electric wire 211 in the inner winding layer 21A to the one end side L1 in the axial direction, and the outer winding layer ( (Second winding layer) 21B is formed.
Thus, from the axial direction one end side L1 of the primary spool 22, the winding start end 212 of the primary wire 211 in the inner winding layer 21A, the winding end end 213 of the primary wire 211 in the outer winding layer 21B, and a pair of sensor signals The primary coil 2 is formed by drawing the end of the wire 751.

  In the ignition coil 1, when a pulse-like spark generation signal is transmitted from the ECU to the igniter 52, the power control circuit in the igniter 52 operates, a current flows through the primary coil 2, and the central core 41 and the outer core 42 are connected. A passing magnetic field is formed. And when the electric current which flows into the primary coil 2 is interrupted | blocked, the induction magnetic field which passes the center core 41 and the outer periphery core 42 is formed toward the direction opposite to the formation direction of the said magnetic field. Due to the formation of the induction magnetic field, an induced electromotive force (back electromotive force) is generated in the secondary coil 3, and a spark can be generated from the pair of electrode portions 74 of the spark plug 7 attached to the ignition coil 1.

  In the ignition coil 1 of this example, a pair of sensor signal lines 751 are arranged between the inner winding layer 21A and the outer winding layer 21B in the primary coil 2 and drawn out to the connector unit 5. Accordingly, the pair of sensor signal lines 751 can be covered with the inner winding layer 21 </ b> A and the outer winding layer 21 </ b> B in the primary coil 2. For this reason, even if the pair of sensor signal lines 751 is routed to the igniter 52 through the vicinity of the secondary coil 3, due to the influence of the spark voltage (high voltage), the influence of the magnetism remaining after the occurrence of the spark, etc. It is possible to effectively suppress noise from being superimposed on the pair of sensor signal lines 751.

  Therefore, according to the ignition coil 1 of this example, when the pair of sensor signal lines 751 is wired to the igniter 52 through the vicinity of the secondary coil 3, noise is superimposed on the pair of sensor signal lines 751. Can be effectively suppressed.

(Example 2)
In this example, as shown in FIG. 5, the sensor signal line 751 is arranged along the axial direction L between the inner winding layer 21 </ b> A and the outer winding layer 21 </ b> B in the primary coil 2.
The outer winding layer 21B of the primary coil 2 in this example has a part in the circumferential direction C by sandwiching the sensor signal line 751 between the inner winding layer 21A in a part in the circumferential direction C. A winding protrusion 215 protruding outward in the radial direction R is formed. The coil case 43 disposed on the outer peripheral side of the primary coil 2 has a case protrusion 431 at a position corresponding to the winding protrusion 215. And this case protrusion part 431 is arrange | positioned in the clearance gap 422 formed between the end surfaces 421 of the circumferential direction C in the said outer periphery core 42. As shown in FIG.

In this example, the sensor signal line 751 can be arranged along the axial direction L using the space formed by the gap 422 in the outer peripheral core 42. Therefore, the sensor signal line 751 can be wired while preventing the outer diameter of the ignition coil 1 from increasing. In this example, the length of the sensor signal line 751 can be shortened.
Also in this example, other configurations are the same as those of the first embodiment, and the same effects as those of the first embodiment can be obtained.

  The structure of the ignition coil 1 shown in the first and second embodiments can be similarly adopted when the sensor 75 is a knock sensor, a plague sensor, a temperature sensor, a proximity sensor, or the like.

Explanatory drawing which shows the cross section in the axial direction of the ignition coil in the state before mounting | wearing with a spark plug in Example 1. FIG. Explanatory drawing which shows the cross section in the axial direction of the ignition coil in the state which mounted | wore with the spark plug in Example 1. FIG. Explanatory drawing which shows the cross section in the axial direction of the state which wound the primary coil and the sensor signal wire around the outer periphery of the primary spool in Example 1. FIG. Explanatory drawing which shows the cross section in the horizontal direction of the coil main-body part of an ignition coil in Example 1. FIG. Explanatory drawing which shows the cross section in the horizontal direction of the coil main-body part of an ignition coil in Example 2. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ignition coil 11 Coil main-body part 2 Primary coil 21 Winding layer 21A Inner winding layer 21B Outer winding layer 211 Primary electric wire 22 Primary spool 3 Secondary coil 32 Secondary spool 41 Central core 42 Outer core 422 Clearance 43 Coil case 5 Connector portion 52 Igniter 6 Plug base portion 7 Spark plug 75 Sensor 751 Sensor signal line 8 Engine 81 Plug hole L Axial direction C Circumferential direction R Radial direction

Claims (6)

A coil body provided with a primary coil and a secondary coil is provided at one end in the axial direction with a connector portion for electrical connection with the outside, and at the other end in the axial direction of the coil main body, a spark is generated by the secondary coil. In an ignition coil comprising a spark plug for generating a spark plug and a sensor for measuring a state quantity in a cylinder of an engine in the spark plug,
The primary coil is formed by winding a primary wire a plurality of times in the axial direction and winding a plurality of layers in the radial direction to form a plurality of winding layers,
The signal line of the sensor is disposed between the inner winding layer located inside the plurality of winding layers and the outer winding layer located outside the inner winding layer, and the connector portion An ignition coil characterized by being pulled out to the end.   2. The ignition coil according to claim 1, wherein the signal line of the sensor is disposed by being wound a plurality of times in the axial direction between the inner winding layer and the outer winding layer.   2. The ignition coil according to claim 1, wherein the signal line of the sensor is disposed along the axial direction between the inner winding layer and the outer winding layer. In claim 3, an outer peripheral core made of a magnetic material is disposed on the outer peripheral side of the primary coil and the secondary coil,
The outer peripheral core is formed with a gap between the circumferential end faces,
The ignition coil according to claim 1, wherein a signal line of the sensor is arranged along an axial direction using a space formed by the gap.   5. The primary coil according to claim 1, wherein the primary coil forms two winding layers, and the signal line of the sensor includes a first winding layer as the inner winding layer. An ignition coil is disposed between the second winding layer as the outer winding layer.   The ignition coil according to any one of claims 1 to 5, wherein the sensor is a combustion pressure sensor that detects a combustion state in a cylinder of the engine.

Images