JPH05175058A - Ignition coil for internal combustion engine - Google Patents

Abstract

PURPOSE:To ensure the waterproofness of a core and to easily ground the core in an ignition coil wherein the core on which a primary coil and a secondary coil have been wound is housed in a case and the case is attached to an internal combustion engine. CONSTITUTION:A primary-coil assembly 10 and a secondary-coil assembly 20 are mounted on cores 2, 3; they are housed inside a case 30; a conductive plate spring 7 (an elastic member) is laid so as to come into contact with a collar 60 (a conductive member) mounted on a fange part 30b and with the core 2. The collar 60 and the core 2 are energized by the plate spring 70 to a direction in which the part between them is expanded; the cores 2, 3 are held in a pressure-contacted state. When the case 30 is attached to a cylinder head cover 100 by means of a bolt 80, the cores 2, 3 are connected electrically to an internal combustion engine via the plate spring 70 and the collar 60.

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 internal combustion engine, and more particularly to an ignition coil for an internal combustion engine in which a core wound with a primary coil and a secondary coil is housed in a case and the case is attached to the internal combustion engine. ..

[0002]

2. Description of the Related Art An ignition coil for an internal combustion engine comprises a metal core wound with a primary coil and a secondary coil, which are housed in a case and filled with a thermosetting resin. Type ignition coil is widely used, for example, Japanese Patent Laid-Open No. 61-107713 and Japanese Patent Laid-Open No. 2-3770.
No. 5, for example. In the former publication,
It has been proposed to fix an end plate of a predetermined shape to the end surface of the core to prevent cracking of the resin case.In the latter publication, the specifications of the core and the permanent magnet interposed between the core are specified. There is.

[0003]

DISCLOSURE OF THE INVENTION Problem to be Solved by the Invention
In the ignition coil shown in FIG. 7 and FIG. 8 of Japanese Patent Publication No. 05, a flange portion is formed so as to extend from the core, and a hole is bored in this flange portion. Then, a bolt is usually inserted through this hole and fixed to a cylinder head cover or the like of the internal combustion engine. As a result, the ignition coil is attached to the internal combustion engine while the core is grounded.

In the above-described ignition coil mounting structure, the core is generally exposed between the holes formed in the core and the bolts and exposed to the outside air. For this reason, when water enters from the exposed portion of the core, rust is generated in the core, and depending on the material, the primary bobbin is hydrolyzed, which may cause insulation failure of the primary coil.

On the other hand, if the entire core is housed in the case, the lead wire is joined to the core, and the lead wire is taken out of the case and electrically connected to the internal combustion engine, the core is exposed. Although it can be grounded without having to do so, not only does it have a complicated structure, but also it is difficult to handle the lead wires and electrically connect to the internal combustion engine, and workability is reduced.

Therefore, in the present invention, in the ignition coil for an internal combustion engine in which the core wound with the primary coil and the secondary coil is housed in the case and the case is attached to the internal combustion engine, the waterproofness of the core is ensured and the core is easily The purpose is to allow the core to be grounded.

[0007]

In order to achieve the above object, the present invention provides a core forming a magnetic path, a primary coil and a secondary coil wound around the core, and the primary coil and the secondary coil. And an ignition coil for an internal combustion engine, comprising a case for accommodating the core, the conductive member being mounted on the case, and the conductive member and the core being in contact with and interposed between the conductive member and the core. A conductive elastic member for urging in the opening direction is provided, and the core is electrically connected to the internal combustion engine via the elastic member and the conductive member.

In the above ignition coil for an internal combustion engine, a flange portion is formed on the case, the conductive member is mounted on the flange portion, and the ignition coil is attached to the internal combustion engine through the flange portion and the conductive member. Is desirable.

Further, according to the present invention, a core having a pair of U-shaped members and arranged so that the end surfaces of the leg portions of the U-shaped members face each other, and a primary wound around the core. An ignition coil for an internal combustion engine, comprising a coil and a secondary coil, a case accommodating the primary coil, the secondary coil, and the core, and mounting the case to an internal combustion engine, wherein the case is
The U-shaped member has a flange portion extending along an axis substantially parallel to the leg portion, a conductive member mounted on the shaft of the flange portion, and abutting on the conductive member and the core. And a conductive elastic member that urges them in a direction to expand between them, and is configured to electrically connect the core to the internal combustion engine via the elastic member and the conductive member. Good to do.

[0010]

In the ignition coil for an internal combustion engine according to the present invention, the core is wound with the primary coil and the secondary coil, which are housed in the case, and the conductive member and the core mounted on the case are contacted with each other. A conductive elastic member is interposed so as to be in contact with each other. The elastic member urges the conductive member and the core in a direction of expanding the core, and the core is held in a state of being pressed against the case. Then, when the case is attached to the internal combustion engine, the core is electrically connected to the internal combustion engine via the elastic member and the conductive member, and properly grounded. When the primary current supplied to the primary coil is intermittent, the magnetic flux changes in the core, and a high voltage is induced in the secondary coil.

When the conductive member is attached to the flange portion of the case, the conductive member can be electrically connected at the same time when the case is attached to the internal combustion engine by, for example, a bolt inserted through the flange portion. Also in this case, the core is not exposed to the outside of the case and is stably held in the case.

A core having a pair of U-shaped members,
A U-shaped member provided with a case having a flange portion extending along an axis substantially parallel to the leg portion of the U-shaped member includes, for example, a permanent magnet between end faces of one leg portion of both U-shaped members. Can be installed. Since the end faces of the leg portions of both U-shaped members are biased toward each other by the elastic member, the end faces of one leg portion of both U-shaped members and the end faces of the other leg portions are permanently attached to each other. Close contact with the magnet. This prevents formation of a gap that may occur between both U-shaped members during assembly or the like.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of an ignition coil for an internal combustion engine of the present invention will be described below with reference to the drawings. 1 to 3 show an embodiment of an ignition coil according to the present invention. The ignition coil 1 comprises a coil assembly 1a housed in a case 30, which is attached to a cylinder head cover 100 of an internal combustion engine. .. The coil assembly 1a has a pair of U-shaped cores 2 and 3, and a primary coil assembly 10 and a secondary coil assembly 2 are provided at both legs of these cores.
0 is installed.

The cores 2 and 3 are, as shown in FIG.
The leg portions 2a, 3a and the second leg portions 2b, 3b of the connecting portion 2
A U-shaped iron core connected through C and 3C, which is formed by stacking a plurality of grain-oriented silicon steel plates whose rolling direction is the left-right direction in FIG. 3 to form a U-shaped member according to the present invention. The cores referred to in the present invention are formed by arranging the end faces of 2 and 3 so as to face each other. The width of the first leg portions 2a and 3a is larger than the width of the second leg portions 2b and 3b from the relationship with the permanent magnet 5 described later, and the tip end portions of the first leg portions 2a and 3a are It has been widened.

These cores 2 and 3 are molded with a thermoplastic material, and a mold layer 4 is closely formed on each of them. As the thermoplastic material forming the mold layer 4, for example, a polyolefin-based thermoplastic elastomer (T
A mixture of PE) with a predetermined proportion of the modifier is used. As is well known, this thermoplastic elastomer is a polymeric material that has rubber elasticity at the same level as vulcanized rubber at normal temperature, is easily plasticized at high temperature, and can be molded by the same processing method as a thermoplastic resin. .. As the modifier to be mixed with the thermoplastic elastomer, an ethylene / acrylic acid ester / maleic anhydride terpolymer having excellent adhesiveness to metal, affinity for resin, and rubber elasticity is used. The ratio is 5 to 40%.

The mold layer 4 is not formed on the end surfaces of the first leg portions 2a, 3a and the second leg portions 2b, 3b of the cores 2, 3 which face each other. Further, the outer surface of the intermediate portion of the connecting portion 2c of the core 2 is not exposed with the mold layer 4 as shown in FIGS. 4 and 6, and is an exposed portion 2d. In the present embodiment, as shown in FIGS. 4 and 5, the mold layers 4 on the front and back surfaces of the first leg 2a and the second leg 2b are thinly formed. It may be configured such that the layer 4 is not formed.

As shown in FIG. 3, the first legs 2a, 3a
A permanent magnet 5 is interposed between the end faces of and and is sandwiched between the two. As the permanent magnet 5, a rare earth magnet which is a sintered body of samarium-cobalt (Sm-Co) -based metal, which has a large residual magnetic flux density and is hard to be demagnetized, is used. For example, the magnetic flux density under normal conditions is 0.8T (tesla), and the magnetic flux density in the opposite direction when the primary coil 12 is energized is 0.7T even at a temperature of 150 ° C.
A material that does not demagnetize is used until.

The permanent magnet 5 has a substantially square shape, and the width of one side is the same as the width of one side of the end faces of the first legs 2a, 3a of the cores 2, 3, and the width of the other side is the first leg 2a. , 3a is set to be the same as the width (thickness) of the other side of the end faces of the permanent magnets 5, so that the cross-sectional area of the permanent magnet 5 is the same as the area of the end faces of the first leg portions 2a, 3a of the cores 2, 3. It is larger than the area of the end faces of the second legs 2b and 3b. The permanent magnet 5 is the primary coil 1
It is arranged so as to be in the direction opposite to the direction of the magnetic flux formed in the cores 2 and 3 when the current is applied to the core 2.

A primary coil assembly 10 is mounted around the first legs 2a and 3a of the cores 2 and 3. The primary coil assembly 10 is formed by winding a primary coil 12 around a primary bobbin 11. The primary bobbin 11 is a resin cylindrical body having a substantially rectangular cross section formed by insert resin molding and having the primary terminals 13a and 13b shown in FIG. 2. Collar portions 11a are formed between both ends of the resin bobbin. The windings of the primary coil 12 are wound in two layers or four layers. Figure 2
As shown in FIG. 3, both ends of the winding of the primary coil 12 are sandwiched by the claws of the primary terminals 13a and 13b, respectively, and soldered.

A secondary coil assembly 20 is mounted around the second legs 2b and 3b of the cores 2 and 3. The secondary coil assembly 20 is formed by winding a secondary coil 22 around a secondary bobbin 21. The secondary bobbin 21 is formed by insert resin molding and has a forked secondary terminal 2 shown in FIG.
3a and a secondary terminal 23b, and is a resin tubular body having a substantially rectangular cross section in which a plurality of collar portions 21a are formed at predetermined intervals in the axial direction. Therefore, a plurality of grooves 21b are formed between these flange portions 21a, and the windings of the secondary coil 22 are sequentially wound in these grooves 21b from right to left in FIGS. There is.

As shown in FIG. 2, the winding start of the winding of the secondary coil 22 is wound around one side of the bifurcated secondary terminal 23a embedded in the right end of the secondary bobbin 21 and soldered, and the other side. The lead 8a of the diode 8 is soldered to the side. The winding end of the secondary coil 22 is connected to the secondary terminal 23b. The secondary terminal 23b is provided with a hole provided with a claw, and a terminal 7a of a high-voltage connector 7 described later is press-fitted into this hole and electrically connected.

As shown in FIGS. 1 and 7, the case 30 has an open upper surface, an opening 30a is formed on one side surface, and a side surface opposite to the opening 30a is substantially parallel to the legs of the cores 2 and 3. This is a housing made of synthetic resin in which a flange portion 30b is formed so as to extend along the axis. A support portion 30c is formed on the bottom of the case 30, and a high-voltage connector 7 is integrally formed by insert resin molding, and its terminal 7a (FIG. 2) extends into the case 30. Also, the case 30
The connector 6 is fitted in the opening 30a on the side surface of the connector. The connector 6 is formed by insert resin molding and incorporates the connector terminals 6a and 6b. The connector terminal 6a is connected to a battery (not shown),
The connector terminal 6b is connected to a control circuit (not shown), commonly called an igniter.

Further, a collar 60 is embedded in the flange portion 30b by insert resin molding. Color 60
Is a conductive member of the present invention, and is formed of a conductive material such as aluminum, has a tubular body portion 60a and an extending portion 60b, and both axial end surfaces of the tubular body portion 60a are exposed outside the case. In addition, the end surface of the extending portion 60b is the case 30.
It is integrally molded with the flange portion 30b of the case 30 so as to be exposed inside. A bolt 80 is inserted through the washer 60a into the tubular portion 60a and is supported at one end of the tubular portion 60a.

As shown in FIGS. 1 and 2, an elastic member 70 is interposed between the end face of the extending portion 60b of the collar 60 and the exposed portion 2d of the core 2 to electrically connect the two. Has been done. The elastic member 70 includes a main body 70b of a leaf spring having conductivity and an engaging portion 70 whose one end is bent at a substantially right angle.
b and a pressing portion 70c whose other end is folded back, and are arranged as shown in FIGS. 1 and 2. That is, the locking portion 70
b is locked to the mold layer 4 on the outer surface of the core 2,
a comes into contact with the exposed portion 2d of the core 2 and the pressing portion 70
c contacts the end surface of the extending portion 60b of the collar 60, and the core 2
The core 3 abutting on the connector 6 is urged in the direction of pressing the inner surface of the case 4 on the connector 6 side. Therefore, with respect to the cores 2 and 3, the gap between the end faces of the second leg portions 2b and 3b shown in FIG. 3 and the gap between the end faces of the first leg portions 2a and 3a and the permanent magnet 5 are gradually approaching zero. Bias has been added to.

The procedure for assembling the ignition coil 1 having the above-described structure will be described. The first and second cores 3 of the one core 3 are provided in the hollow portions of the primary coil assembly 10 and the secondary coil assembly 20, which are arranged side by side. Legs 3a, 3b are inserted, the permanent magnet 5 is housed in the primary bobbin 11, and then the first and second legs 2a, 2b of the other core 2 are inserted. As a result, the permanent magnet 5 is sandwiched between the first leg portions 2a and 3a of the cores 2 and 3, respectively.

Then, the connector terminals 6a and 6b of the connector 6 and the primary terminals 13a and 13b of the primary coil assembly 10 are joined by resistance welding. Further, the lead 8b of the diode 8 is locked in the hole formed in the primary terminal 13b and then soldered, and the lead 8a of the diode 8 is soldered to the secondary terminal 23a of the secondary coil assembly 20. It should be noted that the diode 8 is provided with 1 to 3 generated when the primary coil 12 is energized.
It prevents a spark plug (not shown) from flying due to a voltage of kV.

Thus, as shown in FIG. 7, the coil assembly 1a is formed, and after the coil assembly 1a is disposed in the case 30 and properly supported by the support portion 30c, the elastic member 70 is attached to the exposed portion 2d and the collar 60. It is interposed between the tip end surface of the extending portion 60b. As a result, the main body 70a is exposed to the exposed portion 2d of the core 2.
And the pressing portion 70c abuts on the end surface of the extending portion 60b of the collar 60, and the core 2 and the core 3 are pressed against each other by the urging force of the pressing portion 70c.
Is pressed against the inner surface of the.

After being assembled in this manner, a thermosetting synthetic resin, for example, an epoxy resin is filled in the gap in the case 30, and the resin is cured as shown by the dotted lines in FIG.
Is formed. As a result, the primary coil 12 and the secondary coil 22 are impregnated and fixed, and the insulation that can withstand the high output voltage of the secondary coil 22 is secured. Also, the core 2,
Since the mold layer 4 formed in No. 3 has an affinity for the synthetic resin, the resin portion 9 is in close contact with and bonded to the mold layer 4. The resin portion 9 is omitted in FIGS. 1 and 2.

The ignition coil 1 having the above structure is fixed to the cylinder head cover 100 by the bolts 80 inserted into the collar 60. As a result, the cores 2 and 3 are electrically connected to the cylinder head cover 100 via the elastic member 70 and the collar 60. That is, the cores 2 and 3 are grounded.

Thus, in the ignition coil 1, for example, the right side of the permanent magnet 5 in FIG. 3 is the N pole, and the flow of magnetic flux circulates in the cores 2 and 3 to form a closed loop. There is almost no leakage of magnetic flux in this state. When the primary coil 12 is energized by a control circuit (not shown) and a primary current is supplied, the magnetic flux flows in the direction opposite to the magnetization direction of the permanent magnet 5. When the primary current is cut off, a counter electromotive force is induced in the secondary coil 22 and a high voltage of 30 to 40 kV is generated. This high voltage is applied to an ignition plug (not shown) via the secondary terminal 23b and the high voltage connector 7.

In the ignition coil 1, since the cores 2 and 3 are housed in the case 30 and are not exposed to the outside, rust unlike the conventional example does not occur. Further, since the cores 2 and 3 are pressed into contact with each other by the elastic member 70 and these cores are closely contacted and held in a stable state, it is possible to secure a constant ignition performance without causing variations in ignition performance among the ignition coils. it can. Moreover, the bolt 80
If it is fixed to the cylinder head cover 100 by means of the elastic member 70 and the collar 60, the cylinder head cover 1
00, the cores 2 and 3 can be easily grounded without additional wiring.

FIG. 8 relates to another embodiment of the ignition coil of the present invention. The elastic member 70 of the above-mentioned embodiment is made of a spring material, whereas the elastic member 71 of this embodiment is made of a conductive material. It is formed in a shape shown in FIG. 9 with a conductive rubber or a conductive resin. That is, the locking portion 71 is attached to one end of the main body 71a.
While b is extended and formed, a step portion 71c is formed at the other end so as to match the step formed between the inner surface of the case 30 and the collar 60. Since the other structures are substantially the same as those of the above-described embodiment, the same reference numerals are given and the description thereof will be omitted. Thus, also in this embodiment, the cores 2 and 3 are pressed against each other by the elastic member 71, and are properly grounded via the elastic member 71 and the collar 60 without being exposed to the outside of the case 30.

[0033]

Since the present invention is configured as described above, it has the following effects. That is, in the ignition coil for an internal combustion engine of the present invention, the core is not exposed to the outside of the case, and is stably held in the case by the elastic member, and the elastic member and the conductive member attached to the case. Since it is electrically connected to the internal combustion engine via the, the core can be easily grounded and good workability can be secured.

A core having a pair of U-shaped members,
A U-shaped member having a case having a flange portion extending along an axis substantially parallel to the leg portion of the U-shaped member has both U
Since a permanent magnet can be interposed between the leg portions of the character-shaped member, the output of the ignition coil can be increased. Since the end faces of the leg portions of both U-shaped members are urged by the elastic member in the direction of approaching each other, the end faces of one leg portion of both U-shaped members and the end faces of the other leg portions are The permanent magnet and the permanent magnet can be disposed in close contact with each other, so that a gap that may occur between both U-shaped members during assembly can be prevented and stable ignition performance can be secured. ..

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of an ignition coil according to an embodiment of the present invention.

FIG. 2 is a plan view of an ignition coil according to an embodiment of the present invention.

FIG. 3 is a cross-sectional view of an ignition coil according to an embodiment of the present invention.

FIG. 4 is a plan view of one U-shaped core that constitutes the ignition coil according to the embodiment of the present invention.

FIG. 5 is a front view of one U-shaped core forming the ignition coil according to the embodiment of the present invention.

FIG. 6 is a side view of one U-shaped core that constitutes the ignition coil according to the embodiment of the present invention.

FIG. 7 is an assembly diagram of an ignition coil according to an embodiment of the present invention.

FIG. 8 is a vertical cross-sectional view of an ignition coil according to another embodiment of the present invention.

FIG. 9 is a front view of an elastic member used in an ignition coil according to another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ignition coil 2,3 core, 2a 1st leg part, 2b 2nd leg part, 2d 2nd exposure part 3a 1st leg part, 3b 2nd leg part 4 Mold layer 5 Permanent magnet 6 Connector 7 High voltage connector, 7a Terminal 9 Resin part 10 Primary coil assembly 11 Primary bobbin 12 Primary coil 13a, 13b Primary terminal 20 Secondary coil assembly 21 Secondary bobbin 22 Secondary coil 23a, 23b Secondary terminal 30 Case 30a Opening 30b Flange part 30c Support part 30d Protrusion 60 Collar (conductive member) 60a Main body 60b Extended portion 70,71 Elastic member 100 Cylinder head cover

Claims (3)

[Claims] 1. A core for forming a magnetic path, a primary coil and a secondary coil wound around the core, a case for accommodating the primary coil, the secondary coil and the core, and the case for an internal combustion engine. In an internal combustion engine ignition coil to be attached, a conductive member to be mounted on the case, and a conductive elastic member for contacting and interposing the conductive member and the core, and urging in a direction to expand between the two, An ignition coil for an internal combustion engine, wherein the core is electrically connected to the internal combustion engine through the elastic member and the conductive member. 2. A flange portion is formed on the case, the conductive member is attached to the flange portion, and the flange portion and the conductive member are attached to the internal combustion engine. Item 1. An ignition coil for an internal combustion engine according to item 1. 3. A core which has a pair of U-shaped members, and is arranged such that the end surfaces of the legs of each U-shaped member face each other, a primary coil and a secondary coil wound around the core. An ignition coil for an internal combustion engine, comprising a coil, a case for accommodating the primary coil, the secondary coil, and the core, and the case being attached to an internal combustion engine, wherein the case is substantially parallel to a leg portion of the U-shaped member. Having a flange portion extending along the axis, a conductive member to be mounted on the shaft of the flange portion, and a conductive member and the core that are in contact with the conductive member and are urged in a direction to expand between them. And an electrically conductive elastic member, wherein the core is electrically connected to the internal combustion engine via the elastic member and the electrically conductive member.