JP3192170B2 - Ignition coil for internal combustion engine - Google Patents

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 a primary coil wound around a first leg of a core and a secondary coil wound around a second leg of the core. The present invention relates to an ignition coil housed in a case.

[0002]

2. Description of the Related Art An ignition coil of an internal combustion engine has a core wound with a primary coil and a secondary coil. The primary coil is connected to a control circuit for controlling a primary current through a connector. It is connected to a spark plug via a high pressure terminal.

[0003] The connection relationship between the primary coil and the secondary coil is as follows.
For example, as described in Japanese Utility Model Laid-Open Publication No. 59-9524, both ends of a winding of a primary coil are connected to a pair of primary terminals (primary terminals), and one end of a winding of a secondary coil is connected to the primary terminal. The other end is connected to a high voltage terminal (high voltage terminal).

In Japanese Utility Model Application Laid-Open No. 54-144212, mounting feet are provided on each of the primary low voltage terminal and a part of the secondary high voltage terminal, and these feet are inserted and fixed to a primary spool (primary bobbin). An ignition coil provided with a fixing portion is disclosed. Further, Japanese Utility Model Application Laid-Open No. 54-62014 discloses an apparatus in which the winding of a coil is directly connected to a lead wire, and a guide means for the lead wire is integrally formed with a spool. Similarly, Japanese Utility Model Publication No. 54-150911
Japanese Patent Application Laid-Open Publication No. Hei 11 (1995) No. 11-313873 discloses an arrangement in which a code clip is provided on an outer surface of a coil via an insulator, and a lead wire connected to a lead wire of the coil is held by the code clip.

[0005]

In the case of an ignition coil for an internal combustion engine, when the coil is assembled with the coil wound around a bobbin, the end of the winding may be caught by another part or the like and cut off. Therefore, attention must be paid to the transportation, and the assembling work is complicated. For this reason, as described in the above publications, various measures have been taken in connection with the connection between the windings of the coil and the terminals and the like in order to ensure a good connection state and prevent the assembly work from becoming complicated. .

However, if the winding of the coil and the lead wire are connected in advance, the lead wire hinders the assembly work. Also, Japanese Utility Model Application No. 54-144212
If the primary low-voltage terminal and the secondary high-voltage terminal are fixed to the primary spool (bobbin) in advance, as described in Japanese Patent Application Laid-Open Publication No. H10-157, it becomes difficult to connect the coil winding to each terminal.

Therefore, the present invention provides a method for connecting a winding of a primary coil to a primary terminal and a winding of a secondary coil to a secondary terminal .
It is an object of the present invention to provide an ignition coil for an internal combustion engine that facilitates connection with a terminal and can always maintain a good connection state.

[0008]

In order to achieve the above object, the present invention provides a core having a first leg and a second leg,
A primary coil assembly including a primary bobbin for accommodating a first leg of the core and a primary coil wound on the primary bobbin, a secondary bobbin for accommodating a second leg of the core, and the secondary bobbin An internal combustion engine ignition coil comprising a secondary coil assembly having a secondary coil wound in a case, wherein the primary coil assembly is fixed to the primary bobbin and has one end of a winding of the primary coil. And a pair of primary terminals having one end connected to the other and the other end of the winding of the primary coil connected to the other.
The file assembly is secured to the secondary bobbin and
One end of the coil of the coil and the secondary coil
Pair of secondary terminals with the other end of the coil winding connected to the other
Comprising a, a connector in which said each pair of primary terminal end is fixed to the casing has a pair of connector terminals arranged so as to abut, joining the pair of primary terminals to said pair of connector terminals
Together with one of the pair of secondary terminals
Connect to one of the connector terminals via a diode.
It was decided.

[0009]

[0010]

In the ignition coil for an internal combustion engine of the present invention, a pair of primary terminals are fixed to a primary bobbin, and both ends of a winding of the primary coil are connected to these terminals to form a primary coil assembly. Therefore, after the primary coil assembly is accommodated in the case, the primary terminal and the connector terminal
Can be joined, and during the assembling work, they are transported as a primary coil assembly, so that the winding of the primary coil does not catch on other parts or the like. Further, the connection of the secondary coil assembly can be similarly performed.

In the ignition coil for an internal combustion engine configured as described above, when the primary current supplied to the primary coil is intermittent, a change in magnetic flux occurs in the core, and a high voltage is induced in the secondary coil.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of an ignition coil for an internal combustion engine according to the present invention will be described below with reference to the drawings. FIGS. 1 to 4 show an embodiment of an ignition coil according to the present invention. An ignition coil 1 has a pair of U-shaped cores 2 and 3, and a primary coil assembly 10 and a secondary coil assembly 2 are respectively attached to both legs. The next coil assembly 20 is mounted.

Each of the cores 2 and 3 has a first
U having the legs 2a, 3a and the second legs 2b, 3b
The steel core is formed by stacking a plurality of directional silicon steel plates having a vertical rolling direction shown in FIG. 3 in a rolling direction. As is well known, a grain-oriented silicon steel sheet exhibits extremely good magnetic properties in the rolling direction, but the magnetic properties deteriorate at an angle different from the rolling direction. For this reason, in the cores 2 and 3, the connecting portions 2 orthogonal to the rolling direction are provided.
The width of c, 3c is set to 1.5 to 1.8 times the width of the second leg portions 2b, 3b in the rolling direction. For example, when a magnetic flux density of 1.7 T (Tesla) is allowed in the rolling direction, the magnetic flux density of 1.1 T is limited in a direction at 45 ° to the rolling direction, so that the longitudinal direction of the second legs 2 b and 3 b is limited. The width Wc of the connecting portions 2c and 3c extending in a direction orthogonal to the width Wc is approximately equal to the width Wb of the second arms 2b and 3b in the longitudinal direction.
It is set so as to have a relationship of 1.7 / 1.1.

The surfaces of the cores 2 and 3 are covered with an elastic member such as an elastomer, and an elastic member layer 4 is formed. The elastic member layer 4 absorbs the difference in thermal expansion between the cores 2 and 3 and the components surrounding the cores. In this embodiment, the first leg portions 2a and 3a have only the front and back surfaces, Legs 2b,
On the 3b side, the elastomer is covered on both sides only,
You may comprise so that the whole surface may be covered.

As the permanent magnet 5, a rare earth magnet of a sintered body of a samarium-cobalt (Sm-Co) -based metal having a large residual magnetic flux density and being hardly demagnetized is used. For example,
Normal magnetic flux density is 0.8T (tesla) and temperature is 150T.
Even if the magnetic flux density in the opposite direction when the primary coil 12 is energized becomes 0.7 T (tesla) even at ° C., a material that does not demagnetize is used.

The permanent magnet 5 has a substantially square shape, and the width of one side thereof is set to a value within a range of 1.5 to 2.6 times the width of one side of the cross section of the second legs 2b, 3b of the cores 2, 3. It is set to about twice in this embodiment, and is equal to the width of one side of the cross section of the first leg portions 2a and 3a. The width of the other side of the permanent magnet 5 is set to be the same as the width (thickness) of the other side of the cross section of the second legs 2b, 3b of the cores 2, 3, so that the cross-sectional area of the permanent magnet 5 is The cross-sectional area of the first and second legs 2a, 3a is the same as the cross-sectional area of the second legs 2b, 3b.
It is about twice within the range of 5 to 2.6 times. The permanent magnet 5 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 primary coil 12 is energized.

A primary coil assembly 10 is mounted around the first legs 2a, 3a of the cores 2, 3. The primary coil assembly 10 has a primary coil 12 wound around a primary bobbin 11. The primary bobbin 11 is a resin cylinder having a substantially rectangular cross section formed by insert resin molding and having primary terminals 13a and 13b shown in FIG. 1, and has flanges 11a formed at both ends. The winding of the primary coil 12 is wound in two or four layers. FIG.
As shown in FIG. 2, both ends of the winding of the primary coil 12 are wound around primary terminals 13a and 13b, respectively, and soldered.

A secondary coil assembly 20 is mounted around the second legs 2b, 3b of the cores 2, 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, is provided with a secondary terminal 23b shown in FIG. 4, and is a resin cylinder having a substantially rectangular cross section in which a plurality of flanges 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 above to below in FIGS.

As shown in FIG. 1 and FIG.
1a, a support portion 21c is formed extending in the axial direction.
A secondary terminal 23a is fitted in a groove 21d formed in the support portion 21c. The beginning of the winding of the secondary coil 22 is wound around the secondary terminal 23a and soldered. The end of the winding of the secondary coil 22 is wound around the secondary terminal 23b and soldered. The secondary terminal 23b is provided with a hole having a claw, into which a connecting portion 7a of the high-voltage terminal 7 described later is press-fitted.

The case 30 is a housing made of synthetic resin, and has a secondary connector portion 30a formed at the bottom. A high-voltage terminal 7 having a bottomed cylindrical body is accommodated in the secondary connector portion 30a by insert resin molding, and a connection portion 7a extending and formed at the bottom portion penetrates through the bottom surface of the secondary connector portion 30a to form a case. It extends into 30.

An opening is formed in the side surface of the case 30, and the connector 6 is fitted into the opening. The connector 6 has connector terminals 6a and 6b built therein by insert resin molding. The connector terminal 6a is connected to a battery (not shown), and the connector terminal 6b is connected to a control circuit (not shown), commonly called an igniter.

The primary coil assembly 10 and the secondary coil assembly 20 are juxtaposed, and the first and second legs 3a, 3b of one core 3 are inserted into each hollow portion, and are permanently installed in the primary bobbin 11. After housing the magnet 5, the other core 2
The first and second legs 2a and 2b are inserted. Thereby, the permanent magnet 5 is connected to the first leg 2 of each of the cores 2 and 3.
a, 3a. When these assemblies are accommodated in the case 30, the connection portions 7a of the high-voltage terminals 7 are press-fitted into the holes of the secondary terminals 23b and are electrically connected.

Then, the connector terminals 6a and 6b of the connector 6 mounted on the case 30 and the primary terminals 13a and 13b of the primary coil assembly 10 are respectively joined by resistance welding. Further, after the lead 8b of the diode 8 is clamped by the claw 6c provided upright on the connector terminal 6b, it is joined by resistance welding, and the lead 8a of the diode 8 is joined to the secondary terminal 23a of the secondary coil assembly 20 by resistance welding. Joined.
The diode 8 is connected to an ignition plug 4 described later by a voltage of 1 to 3 kV generated when the primary coil 12 is energized.
0 is to prevent a fire.

The space inside the case 30 is filled with a thermosetting synthetic resin, for example, an epoxy resin, and cured to form a resin portion 9. As a result, the primary coil 12 and the secondary coil 22 are impregnated and fixed, and the insulation property that can withstand the output high voltage of the secondary coil 22 is secured.

The ignition coil 1 is mounted on a cylinder head cover 53 of an internal combustion engine 50 for each cylinder as shown in FIG. The internal combustion engine 50 in this embodiment includes a plurality of cylinders arranged in series, and FIG. 5 shows a cross section of a cylinder head of one of the cylinders. The cylinder head 52 of the internal combustion engine 50 is integrally formed with an intake port and an exhaust port that open to the combustion chamber 51 for each cylinder, and a pair of an intake valve 56 and an exhaust valve 57 are mounted on these, respectively. , FIG. 5 shows only one of these sets. That is, in the present embodiment, a so-called four-valve engine is provided with a pair of intake valve 56 and exhaust valve 57 for each cylinder, that is, a so-called four-valve engine. It has become.

In the internal combustion engine 50, the cylinder head 5
A cylinder head cover 53 is joined to the upper part of the cylinder head 2, and an oil chamber 55 is defined between the two. Cylinder head 5
A mounting hole 54 is formed between the second intake valve 56 and the exhaust valve 57 from the oil chamber 55 toward the combustion chamber 51.
A spark plug 4 is inserted into a small diameter hole of the mounting hole 54 on the combustion chamber 51 side.
0 is screwed, and the electrode portion is fixed in a state where it is exposed inside the combustion chamber 51.

On the other hand, on the top of the cylinder head cover 53,
A mounting recess 53a is formed to face the opening of the mounting hole 54 to the oil chamber 55, and an insertion hole 53b is formed in the bottom of the mounting recess 53a. A cylindrical shielding cylinder 41 formed of metal is inserted into the mounting hole 54,
One end is fixed to the vicinity of the lower end of the mounting hole 54 by press fitting or the like. The other end of the shielding cylinder 41 protrudes from the mounting hole 54 and extends to the insertion hole 53b of the mounting recess 53a.

The ignition coil 1 has a secondary connector 30
After an annular seal member 42 is fitted around the outer periphery of the cylinder a, the annular seal member 42 is inserted into the shielding cylinder 41, and its main body is accommodated in the mounting recess 53 a of the cylinder head cover 53. As a result, the secondary connector 30a of the ignition coil 1 is electrically connected to one end of the connecting member 43, and the other end is electrically connected to the ignition coil 40. As described above, the ignition coil 1 of the present embodiment is small in size, and particularly the main body is formed thin, so that it can be easily housed in the cylinder head cover 53. Further, the storage chamber in the shielding cylinder 41 and the oil chamber 55 are completely separated from each other, and the oil droplets in the oil chamber 55 do not enter the shielding cylinder 41.

The operation of this embodiment will be described. The internal combustion engine 50 is started, and the intake valve 56 and the exhaust valve 57 are driven at a predetermined cycle. Then, the primary current of the ignition coil 1 is controlled by an ignition signal output in a predetermined order according to the rotation of the internal combustion engine 50, and a predetermined high voltage is generated in the secondary coil 22. This high voltage is applied to the high voltage terminal 7
And applied to the ignition plug 40 via the connecting member 43,
Spark discharge occurs at the electrode portion at the tip of the spark plug 40, and the compressed air-fuel mixture in the combustion chamber 51 is ignited.

In the ignition coil 1, for example, the upper part of the permanent magnet 5 in FIG. 3 is an 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 a direction opposite to the magnetization direction of the permanent magnet 5. And
When the primary current is cut off, a back 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 the ignition plug 40 via the secondary terminal 23b and the high voltage terminal 7.

In the ignition coil 1 of this embodiment, a large change in effective magnetic flux can be secured by the permanent magnet 5 interposed between the cores 2 and 3. In particular, the permanent magnet 5 is housed in the primary coil 12 and is arranged at an appropriate position at the center in the axial direction, and furthermore, the cross-sectional area of the minimum cross-section (the second leg 2b, 3b) of the cores 2, 3 Permanent magnet 5 for
Is about twice as large. Therefore, the magnetic flux density formed in the primary coil 12 becomes large with respect to the magnetomotive force caused by the application of the primary current, and the discharge energy increases,
Since the change in the magnetic flux linking the secondary coil 22 is large, the output voltage of the secondary coil 22 is large.

[0032]

Since the present invention is configured as described above, the following effects can be obtained. That is, according to the present invention,
Both ends of the winding of the primary coil are connected to a pair of primary terminals fixed to the primary bobbin to form a primary coil assembly. The primary coil assembly is mounted on the first leg of the core and the second coil is mounted on the second leg. a secondary coil assembly the legs are configured to be mounted primary Koirua
The assembly is fixed to the primary bobbin and one of the windings of the primary coil.
One end and the other end of the primary coil winding to the other end.
With a pair of primary terminals connected to
Assembly is fixed to the secondary bobbin and the secondary coil winding
To one end and the other end of the secondary coil winding
A pair of secondary terminals connected to the other,
Also converts a pair of primary terminals into a pair of connector terminals
Along with joining, one of the pair of secondary terminals
Connect to one of the connector terminals via a diode.
Which is configured to so that, winding and secondary Terminal connections and secondary coil windings and the primary terminal of the primary coil
The connection of the cables is easy, and it is possible to easily assemble while always maintaining a good connection state.

[0033]

[Brief description of the drawings]

FIG. 1 is a plan view of an ignition coil according to an embodiment of the present invention.

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

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

FIG. 4 is a longitudinal sectional view of an ignition coil according to one embodiment of the present invention.

FIG. 5 is a sectional view of an internal combustion engine provided with an ignition coil according to one embodiment of the present invention.

[Explanation of symbols]

1 ignition coil 2 core, 2a first leg, 2b second leg,
2c connecting part 3 core, 3a second leg, 3b second leg,
3c connection part 4 elastomer 5 permanent magnet 6 connector, 6a, 6b connector terminal 7 high voltage terminal, 7a connection part 8 diode 9 resin part 10 primary coil assembly 11 primary bobbin, 11a, 11b flange, 11c
Notch 12 Primary coil 13a, 13b Primary terminal 20 Secondary coil assembly 21 Secondary bobbin, 21a Flange, 21b groove,
21c Support part 22 Secondary coil 23a, 23b Secondary terminal 30 Case 30a Secondary connector part

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01F 38/12 F02P 15/00 303

Claims (1)

(57) [Claims] 1. A primary coil assembly comprising a core having a first leg and a second leg, a primary bobbin for accommodating the first leg of the core, and a primary coil wound on the primary bobbin. And a secondary coil assembly including a secondary bobbin for accommodating the second leg of the core and a secondary coil wound around the secondary bobbin in a case. , The primary coil assembly
Comprises a pair of primary terminals connected to the other end of the winding of the primary coil to the other with and fixed to the primary bobbin connecting one end of the winding of the primary coil in one direction, the
The secondary coil assembly is fixedly attached to the secondary bobbin.
Connect one end of the secondary coil winding to one and
A pair of secondary terminals with the other end of the secondary coil winding connected to the other
Comprising a Terminal, a connector in which said each pair of primary terminal end is fixed to the casing has a pair of connector terminals arranged so as to abut, joining the pair of primary terminals to said pair of connector terminals And one of the pair of secondary terminals is
Through a diode to one of the pair of connector terminals
An ignition coil for an internal combustion engine, which is connected .