JP2013026560A - Ignition coil for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problems that: when an igniter is not held in a case, this requires a manufacturing device, such as a tool to temporarily fix the igniter during manufacturing; no distance or a narrow distance between an iron core cover and the igniter makes it difficult for insulating resin to enter between the iron core cover and the igniter, thus failing to sufficiently fill the insulating resin; and due to no distance or the narrow distance between the iron core cover and the igniter, the insulating resin between the iron core cover and the igniter is thin, and a crack is likely to occur.SOLUTION: A fixed wall is formed between an iron core cover in a case and an igniter. The iron core cover has at least two kinds of thicknesses on a surface thereof opposed to the fixed wall of the iron core cover. The fixed wall has a height that is not more than half the height of the igniter in a vertical direction. The thickest part of the surface of the iron core cover opposed to the fixed wall is disposed at a position higher than the height of the igniter in the vertical direction.

Description

The present invention relates to an ignition coil for an internal combustion engine.

Conventionally, in order to narrow the engine room and widen the interior space, it has been required to reduce the size of the components arranged in the engine room. The case is provided with a primary coil, a secondary coil, and an iron core. Further, downsizing of an ignition coil for an internal combustion engine in which a coil housing portion filled with a mold resin is disposed outside the plug hole is being promoted. In addition to downsizing the primary coil, secondary coil, and iron core to reduce the size of the entire ignition coil, several configurations are aimed at reducing the size of the case by reducing the distance between the outer iron core and the igniter. Has been proposed. As a typical example of this, for example, Japanese Patent Application Laid-Open No. 2010-027669 (hereinafter “Patent Document 1”) is known.

A cross-sectional view of the ignition coil disclosed in Patent Document 1 is shown in FIG. In FIG. 16, a primary coil 103 wound around a primary bobbin 102 is provided in an insulating case 101. A secondary bobbin 104 is provided outside the primary bobbin 102. A secondary coil 105 is wound around the secondary bobbin 104. The cylindrical primary bobbin 102 has an I magnetically coupled to the primary coil 103 and the secondary coil 105.
A center iron core 106 of the mold penetrates. The center iron core 106 forms a closed magnetic circuit with a C-shaped side iron core 107 surrounding the primary coil 103 and the secondary coil 105. Here, the primary bobbin 102, the primary coil 103, the secondary bobbin 104, the secondary coil 105, the center iron core 106, and the side iron core 107 constitute an ignition coil 120. The side iron core 107 is covered with a shock-absorbing cover 108 made of a shock-absorbing material, except for the region of the inner wall side surface 100A that is separated from the end face of the center iron core 106. The buffer cover 108 is made of, for example, a thermoplastic elastomer, and the side iron core 107 covered with the buffer cover 108 is formed by insert molding.

In the insulating case 101, an igniter 109 is disposed between an inner wall side surface of the insulating case 101 and a side iron core 107 whose surface is covered with a buffer cover 108. A cutout portion is formed on one side of the opening of the insulating case 101, and a low voltage side connector 112 having a low voltage side terminal 113 is fitted into the cutout portion. Further, the insulation case 101 is provided with a high voltage side connector 110 into which the high voltage side terminal 111 is fitted and is electrically connected to the spark plug. The igniter 109 has three igniter terminals 116. One is electrically connected to the conducting wire of the primary coil 103. 2 after
The book is electrically connected to a low voltage side terminal 113 connected to an electronic control unit (not shown) and a grounded low voltage side terminal 113, respectively. Of the three low-voltage terminals 113, the remaining one that is not electrically connected to the igniter 109
The book is electrically connected to a battery (not shown). The high voltage side terminal 111 connected to the conducting wire of the secondary coil 105 is electrically connected to the spark plug. An ignition coil for an internal combustion engine has been proposed in which an insulating resin 115, which is a thermosetting epoxy resin, is filled in the insulating case 101 and then solidified.

As another example, Japanese Unexamined Patent Application Publication No. 2009-188364 (hereinafter “Patent Document 2”) is known.

A cross-sectional view of the ignition coil disclosed in Patent Document 2 is shown in FIG. In FIG. 17, a primary coil 221 and a secondary coil 222 arranged on the inner and outer circumferences, a soft magnetic central core 241 arranged on the inner circumference side of the primary coil 221 and the secondary coil 222, a primary coil 221 and a secondary coil And a soft magnetic outer core 242 disposed on the end surface side and the outer peripheral side of the coil 222 in the axial direction. Outer core 242
Is formed by connecting a relay portion 242A disposed on the axial end surface side of the central core 241 and an outer peripheral portion disposed on the outer peripheral side of the primary coil 221 and the secondary coil 222. The ignition coil 201 incorporates an igniter 205 formed by molding an electronic component with resin, and the igniter 205 includes a switching control circuit that performs energization to the primary coil 221 and interruption of energization.

The ignition coil 201 includes a primary coil 221, a secondary coil 222, a central core 241, an outer core 242, and an igniter 205 disposed in a case component 203 made of thermoplastic resin, and the thermosetting resin in the case component 203. Insulating fixing resin 215 is filled and each component is fixed in an insulated state. Further, in the ignition coil 201, in order to effectively suppress the igniter 205 from becoming high temperature, the igniter 205 is disposed so as to face the outer surface of the relay portion 242A in the outer peripheral core 242 and relays with the igniter 205. An ignition coil has been proposed in which a gap 250 between the portion 242A is filled with an insulating fixing resin 215.

JP 2010-027669 A JP 2009-188364 A

However, the conventional ignition coil has the following problems. In other words, in the ignition coil of Patent Document 1, the igniter is disposed on the low voltage side connector side in the insulating case so that the inner wall side surface of the insulating case and the side iron core covered with the buffer cover are sandwiched between the igniter. Therefore, the amount of insulating resin around the igniter is small, the thermal stress of the insulating resin is reduced, the generation of cracks in the insulating resin is suppressed, and the stress on the igniter is also reduced, but the igniter is not held in the case Therefore, a manufacturing apparatus such as a jig for temporarily fixing the igniter at the time of manufacture is required.

In addition, since there is no or narrow distance between the buffer cover and the igniter, the insulating resin is difficult to enter between the buffer cover and the igniter, and there is a possibility that poor filling of the insulating resin occurs. Further, since there is no or narrow distance between the buffer cover and the igniter, the resin layer between the buffer cover and the igniter becomes thin and cracks are likely to occur.

Further, in the ignition coil of Patent Document 2, the igniter is made to face the outer surface of the relay portion in the outer core, so that the heat generated by the igniter itself can be absorbed by the outer core, and the temperature rise of the igniter is effective. However, the problem about the crack of the insulating fixing resin remains. Furthermore, since there is no specific description about the installation of the igniter, a manufacturing apparatus such as a jig for temporarily fixing the igniter at the time of manufacture is required.

The present invention has been made in view of the above problems, and it is possible to simplify the manufacturing process without requiring a manufacturing device such as a jig for temporarily fixing the igniter at the time of manufacturing, and to improve mold resin filling properties between the iron core cover and the igniter. It is an object of the present invention to provide an ignition coil for an internal combustion engine that can be improved and the amount of mold resin between the iron core cover and the igniter can be increased.

In order to solve the above problems, the present invention is configured as follows. That is, a case and a primary coil in which at least a part of an iron core composed of a central iron core and an outer peripheral iron core is accommodated in the case, and a primary winding is wound around a primary bobbin in the case; An internal combustion engine in which a secondary coil having a secondary winding wound around a secondary bobbin is accommodated, an igniter that supplies an ignition signal to the primary coil is provided in the case, and a mold resin is filled in the coil accommodating portion in the case In the engine ignition coil, at least a part of the periphery of the outer peripheral iron core is provided with a resin iron core cover, a fixed wall is formed between the iron core cover and the igniter in the case, and the iron core The cover is an ignition coil for an internal combustion engine characterized in that at least two types of thicknesses are provided on a surface of the iron core cover facing the fixed wall.

In the above-described configuration, the fixed wall may have a height that is ½ or less of the vertical height of the igniter, and the thickest portion of the surface of the iron core cover that faces the fixed wall is the vertical of the igniter. You may arrange | position in the position higher than the height of a direction. Further, the outer peripheral iron core may be arranged such that the magnetic path of the iron core is oriented in a direction perpendicular to the opening surface of the case, and the coil facing portion of the outer peripheral iron core is provided at a position higher than the resin surface of the mold resin. Good. Furthermore, the thickness of the iron core cover provided in the coil facing portion of the outer peripheral iron core may be wider than the thickness of the thinnest portion of the surface of the iron core cover facing the fixed wall.

As described above, at least a part of the periphery of the outer peripheral iron core is provided with a resin iron core cover, and a fixed wall is formed between the iron core cover and the igniter in the case, so that the igniter is fixed by the fixed wall. The manufacturing process can be simplified. Moreover, the internal combustion engine which can improve the filling property of the mold resin between an iron core cover and an igniter because the iron core cover has at least two kinds of thicknesses on the surface facing the fixed wall of the iron core cover. An ignition coil can be realized.

Also, the fixed wall should be less than half the vertical height of the igniter, and the thickest part of the surface facing the fixed wall of the iron core cover should be placed at a position higher than the vertical height of the igniter. Since the gap between the iron core cover and the igniter widens, the filling property of the mold resin between the iron core cover and the igniter can be further improved, and the amount of the mold resin between the iron core cover and the igniter can be increased.

1 is a perspective view of an ignition coil for an internal combustion engine according to a first embodiment of the present invention. It is BB sectional drawing seen from the arrow (A) direction of FIG. It is the C section enlarged view of FIG. It is a top view of the case of the ignition coil which is the 1st example of the present invention. 1 is a circuit diagram of an ignition coil according to a first embodiment of the present invention. FIG. 6 is a perspective view of an ignition coil for an internal combustion engine according to a second embodiment of the present invention. It is EE sectional drawing seen from the arrow (D) direction of FIG. It is the F section enlarged view of FIG. It is a top view of the case of the ignition coil which is the 2nd example of the present invention. FIG. 3 is a circuit diagram of an ignition coil according to a second embodiment of the present invention. FIG. 6 is a perspective view of an ignition coil for an internal combustion engine according to a third embodiment of the present invention. It is HH sectional drawing seen from the arrow (G) direction of FIG. It is the I section enlarged view of FIG. It is a top view of the case of the ignition coil which is the 3rd example of the present invention. It is a circuit diagram of the ignition coil which is the 3rd example of the present invention. 2 is a cross-sectional view of an ignition coil disclosed in Patent Document 1. FIG. 6 is a cross-sectional view of an ignition coil disclosed in Patent Document 2. FIG.

An example showing the embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is a perspective view of an ignition coil for an internal combustion engine according to a first embodiment of the present invention, FIG. 2 is a cross-sectional view taken along the line BB in the direction of the arrow (A) in FIG. 1, and FIG. FIG. 3 is a top view of the ignition coil case according to the first embodiment of the present invention, and FIG. 5 is a circuit diagram of the ignition coil according to the first embodiment of the present invention.

1 to 5, a case 40 forming the outer shape of the ignition coil 90 is formed by a box-shaped integral molding having an opening surface on the upper surface in the vertical direction. Further, the case 40 is formed with a case fixing portion 42 for attaching and fixing the ignition coil 90 to an engine head (not shown). Furthermore, a high voltage tower 44 having a high voltage terminal 60 for supplying a secondary voltage to the spark plug 96 is formed on the bottom surface of the ignition coil 90 so as to protrude into a plug hole formed in the upper part of the engine. ing.

The ignition coil 90 includes an iron core 36 formed by laminating a plurality of thin plates and an iron core 36 formed of an I-shaped center iron core 30 and a B-shaped outer iron core 32, and an outer periphery of the center iron core 30. The primary coil 14 in which the primary winding 12 is wound about 100 turns around the outer periphery of the primary bobbin 10 molded with resin, and the outer periphery of the secondary bobbin 20 molded with resin on the outer periphery of the primary coil 14 The secondary winding 22 is composed of a coil portion of a secondary coil 24 in which the secondary winding 22 is wound about 8000 to 15000 turns. Further, the outer peripheral iron core 32 is arranged so that the magnetic path of the iron core 36 is parallel to the opening surface of the case 40.

Also, a magnet 38 for generating a magnetic flux in the opposite direction to the magnetic flux generated by the primary coil 14 in the magnetic path is provided at one end of the connecting surface of the central iron core 30 and the outer peripheral iron core 32. . Further, a secondary high voltage terminal 26 for supplying a secondary voltage to the high voltage terminal 60 is provided at one end of the secondary bobbin 20, and a primary voltage from the primary coil 14 is supplied to the other end. A secondary low-voltage terminal (not shown) is provided.

An igniter 70 for supplying an ignition signal to the primary coil 14 is provided in the case 40. The igniter 70 includes a switching element and a lead frame. The lead frame includes a base and a collector of the switching element, Each of the emitters is arranged as an igniter terminal 72 for connection to the outside. Further, a connector 46 having a connector terminal 62 for supplying a primary voltage from the battery 92 and an ignition signal from the ECU 94 is formed on the side surface of the case 40.

The connector terminal 62 connects a terminal connecting the battery 92 to the low voltage side of the primary coil 14 and the secondary coil 24, and connecting the igniter terminal 72 arranged on the base side of the igniter 70 from the ECU 94. The terminal is composed of a total of three terminals: the igniter terminal 72 arranged on the emitter side of the igniter 70 and the terminal connecting the outer peripheral iron core 32 to the ground. Further, the igniter terminal 72 disposed on the collector side of the igniter 70 is connected to the high voltage side of the primary coil 14.

Further, the connector terminal 62 and the igniter terminal 72 have a substantially flat metal terminal, and two of the connector terminal 62 and the igniter terminal 72 are led out in the same direction and are electrically connected to each other. They are connected using welding as is realized. Further, the connector terminal 62 and the igniter terminal 72 are led out in a direction perpendicular to the opening surface of the case 40, and the connector terminal 62 extends over the inner wall of the case 40 on the same surface as the connector 46 formed on the case 40. Is arranged.

Further, the periphery of the outer peripheral iron core 32 excluding the connection surface with the central iron core 30 and the magnet 38 is covered with an iron core cover 34 formed of polybutylene terephthalate (hereinafter referred to as “PBT”). . Further, a fixing wall 48 for fixing the igniter 70 is formed between the igniter facing surface 35 of the iron core cover 34 on the inner bottom surface of the case 40 and the igniter 70, and the fixing wall 48 is an inner bottom surface of the case 40. To the igniter 70 in the vertical direction, and is formed on a straight line connecting the igniter facing surface 35 and the igniter 70.

Further, the igniter-facing surface 35 of the iron core cover 34 is formed in three kinds of thicknesses: a thinnest part 35a, an intermediate part 35b, and a thickest part 35c. Further, the intermediate portion 35b is formed at a position higher than the vertical height of the fixed wall 48, and the thickest portion 35c is formed at a position higher than the vertical height of the igniter 70.

The case 40 is filled with a mold resin 80 that realizes electrical insulation of the ignition coil 90 and physical fixation of each member. Further, the mold resin 80 is filled to the vicinity of the opening surface of the case 40, and the iron core 36, the primary coil 14, and the secondary coil 24 are formed on the resin surface near the opening surface of the case 40. Located below 82.

With the above configuration, the fixed wall 48 for fixing the igniter 70 is formed between the igniter facing surface 35 of the iron core cover 34 on the inner bottom surface of the case 40 and the igniter 70. Since 48 fixes the igniter 70, it is not necessary to fix the igniter 70 with a jig. Further, the igniter facing surface 35 of the iron core cover 34 has three types of thicknesses, the thinnest portion 35a, the intermediate portion 35b, and the thickest portion 35c. The intermediate portion 35b is formed on the fixed wall 48. By forming it at a position higher than the height in the vertical direction, the distance L1 between the thinnest part 35a and the igniter 70 is increased, and the gap between the thinnest part 35a and the igniter 70 is widened. The filling property of the mold resin 80 between the portion 35a and the fixed wall 48 can be improved. Further, the thickest portion 35c is formed at a position higher than the vertical height of the igniter 70, so that the distance L2 between the intermediate portion 35b and the igniter terminal 72 is increased, and the intermediate portion 35b and the igniter are increased. Since the gap between the terminals 72 is widened, the filling property of the mold resin 80 between the intermediate portion 35b and the igniter 70 can be improved.

As a modification of the first embodiment, the iron core cover 34 may be formed of polyethylene terephthalate, elastomer, nylon, or the like, and the igniter facing surface 35 of the iron core cover 34 has at least two types of thickness. If necessary, it can be changed as appropriate. The fixed wall 48 can be appropriately changed as long as the fixed wall 48 is formed with a height of ½ or less of the vertical height of the igniter 70. Further, the intermediate portion 35b formed on the igniter facing surface 35 of the iron core cover 34 may be changed to any height as long as it is higher than the vertical height of the fixed wall 48. The thickest portion 35c formed on the igniter facing surface 35 of the iron core cover 34 may be changed to any height as long as it is higher than the vertical height of the igniter 70.

Further, the thickness dimension of the iron core cover 34 and the thickness dimension of the thinnest part 35a and the intermediate part 35b and the thickest part 35c formed on the igniter facing surface 35 of the iron core cover 34 are as follows. You may change to arbitrary dimensions according to design circumstances. Further, the iron core cover 34 is provided around the outer peripheral iron core 32 except for the connection surface with the central iron core 30 and the magnet 38. For example, the iron core cover 34 is lower than the height of the fixed wall 48 of the igniter facing surface 35. Without being provided with the iron core cover 34 at the position, the outer peripheral iron core 32 is exposed, the filling property of the mold resin 80 between the outer peripheral iron core 32 and the fixed wall 48 is improved, etc. It is.

The distance L1 between the thinnest portion 35a and the igniter 70 and the distance L2 between the intermediate portion 35b and the igniter terminal 72 are determined from the igniter facing surface 35 of the iron core cover 34 of the fixed wall 48. The distance between the iron core cover 34 and the igniter 70 may be changed to a distance that can further improve the filling property of the mold resin 80 by changing the dimension in the igniter 70 direction. Furthermore, as long as the fixed wall 48 is formed in a linear range connecting the igniter facing surface 35 and the igniter 70, the shape and the formation position may be arbitrarily changed depending on the design circumstances.

Further, the case 40 has a shape having an opening surface on the upper surface in the vertical direction, but the igniter facing surface 35 of the iron core cover 34 is the thickest portion 35c from the opening surface with the filling direction of the mold resin 80 as the opening surface. As long as the intermediate portion 35b and the thinnest portion 35a are configured in this order, the intermediate portion 35b and the thinnest portion 35a may be arbitrarily changed depending on design circumstances. Further, the outer peripheral iron core 32 may be changed to, for example, a U-shaped outer peripheral iron core other than the square-shaped iron core.

FIG. 6 is a perspective view of an ignition coil for an internal combustion engine according to a second embodiment of the present invention, FIG. 7 is a cross-sectional view taken along the line EE viewed from the direction of the arrow (D) in FIG. 6, and FIG. FIG. 8 is a top view of the ignition coil case according to the second embodiment of the present invention, and FIG. 10 is a circuit diagram of the ignition coil according to the second embodiment of the present invention.

6 to 10, the case 40 forming the outer shape of the ignition coil 90 is formed by box-shaped integral molding having an opening surface on the upper surface in the vertical direction. Further, the case 40 is formed with a case fixing portion 42 for attaching and fixing the ignition coil 90 to an engine head (not shown). Furthermore, a high voltage tower 44 having a high voltage terminal 60 for supplying a secondary voltage to the spark plug 96 is formed on the bottom surface of the ignition coil 90 so as to protrude into a plug hole formed in the upper part of the engine. ing.

The ignition coil 90 includes an iron core 36 formed by laminating a plurality of thin plates and an iron core 36 formed of an I-shaped center iron core 30 and a B-shaped outer iron core 32, and an outer periphery of the center iron core 30. The primary coil 14 in which the primary winding 12 is wound about 100 turns around the outer periphery of the primary bobbin 10 molded with resin, and the outer periphery of the secondary bobbin 20 molded with resin on the outer periphery of the primary coil 14 The secondary winding 22 is composed of a coil portion of a secondary coil 24 in which the secondary winding 22 is wound about 8000 to 15000 turns. Further, the outer peripheral iron core 32 is arranged so that the magnetic path of the iron core 36 is parallel to the opening surface of the case 40.

Also, a magnet 38 for generating a magnetic flux in the opposite direction to the magnetic flux generated by the primary coil 14 in the magnetic path is provided at one end of the connecting surface of the central iron core 30 and the outer peripheral iron core 32. . Further, a secondary high voltage terminal 26 for supplying a secondary voltage to the high voltage terminal 60 is provided at one end of the secondary bobbin 20, and a primary voltage from the primary coil 14 is supplied to the other end. A secondary low-voltage terminal (not shown) is provided.

An igniter 70 for supplying an ignition signal to the primary coil 14 is provided in the case 40. The igniter 70 includes a switching element and a lead frame. The lead frame includes a base and a collector of the switching element, Each of the emitters is arranged as an igniter terminal 72 for connection to the outside. Further, a connector 46 having a connector terminal 62 for supplying a primary voltage from the battery 92 and an ignition signal from the ECU 94 is formed on the side surface of the case 40.

The connector terminal 62 connects a terminal connecting the battery 92 to the low voltage side of the primary coil 14 and the secondary coil 24, and connecting the igniter terminal 72 arranged on the base side of the igniter 70 from the ECU 94. The terminal is composed of a total of three terminals: the igniter terminal 72 arranged on the emitter side of the igniter 70 and the terminal connecting the outer peripheral iron core 32 to the ground. Further, the igniter terminal 72 disposed on the collector side of the igniter 70 is connected to the high voltage side of the primary coil 14.

Further, the connector terminal 62 and the igniter terminal 72 have a substantially flat metal terminal, and two of the connector terminal 62 and the igniter terminal 72 are led out in the same direction and are electrically connected to each other. They are connected using welding as is realized. Further, the connector terminal 62 and the igniter terminal 72 are led out in a direction perpendicular to the opening surface of the case 40, and the connector terminal 62 extends over the inner wall of the case 40 on the same surface as the connector 46 formed on the case 40. Is arranged.

Further, a ground terminal wiring groove 50 for inserting the connector terminal 62 connecting the ground from the outer peripheral iron core 32 is formed on the surface of the inner bottom surface of the case 40.

Further, the periphery of the outer peripheral iron core 32 excluding the connection surface with the central iron core 30 and the magnet 38 is covered with an iron core cover 34 formed of polybutylene terephthalate (hereinafter referred to as “PBT”). . Further, a fixing wall 48 for fixing the igniter 70 is formed between the igniter facing surface 35 of the iron core cover 34 on the inner bottom surface of the case 40 and the igniter 70, and the fixing wall 48 is an inner bottom surface of the case 40. From the height of the igniter 70 in the vertical direction.

The fixed wall 48 is formed between the igniter facing surface 35 of the iron core cover 34 and the igniter 70 so as to avoid the ground terminal wiring groove 50.

Further, the igniter-facing surface 35 of the iron core cover 34 is formed in three kinds of thicknesses: a thinnest part 35a, an intermediate part 35b, and a thickest part 35c. Further, the intermediate portion 35b is formed at a position higher than the vertical height of the fixed wall 48, and the thickest portion 35c is formed at a position higher than the vertical height of the igniter 70.

The case 40 is filled with a mold resin 80 that realizes electrical insulation of the ignition coil 90 and physical fixation of each member. Further, the mold resin 80 is filled to the vicinity of the opening surface of the case 40, and the iron core 36, the primary coil 14, and the secondary coil 24 are formed on the resin surface near the opening surface of the case 40. Located below 82.

With the above configuration, the fixed wall 48 for fixing the igniter 70 is formed between the igniter facing surface 35 of the iron core cover 34 on the inner bottom surface of the case 40 and the igniter 70. Since 48 fixes the igniter 70, it is not necessary to fix the igniter 70 with a jig. Further, the igniter facing surface 35 of the iron core cover 34 has three types of thicknesses, the thinnest portion 35a, the intermediate portion 35b, and the thickest portion 35c. The intermediate portion 35b is formed on the fixed wall 48. By forming it at a position higher than the height in the vertical direction, the distance L3 between the thinnest part 35a and the igniter 70 is increased, and the gap between the thinnest part 35a and the igniter 70 is widened. The filling property of the mold resin 80 between the portion 35a and the fixed wall 48 can be improved. Further, the thickest portion 35c is formed at a position higher than the vertical height of the igniter 70, so that the distance L4 between the intermediate portion 35b and the igniter terminal 72 is increased, and the intermediate portion 35b and the igniter are increased. Since the gap between the terminals 72 is widened, the filling property of the mold resin 80 between the intermediate portion 35b and the igniter 70 can be improved.

As a modification of the second embodiment, the iron core cover 34 may be formed of polyethylene terephthalate, elastomer, nylon, or the like, and the igniter facing surface 35 of the iron core cover 34 has at least two types of thickness. If necessary, it can be changed as appropriate. The fixed wall 48 can be appropriately changed as long as the fixed wall 48 is formed with a height of ½ or less of the vertical height of the igniter 70. Further, the intermediate portion 35b formed on the igniter facing surface 35 of the iron core cover 34 may be changed to any height as long as it is higher than the vertical height of the fixed wall 48. The thickest portion 35c formed on the igniter facing surface 35 of the iron core cover 34 may be changed to any height as long as it is higher than the vertical height of the igniter 70.

Further, the thickness dimension of the iron core cover 34 and the thickness dimension of the thinnest part 35a and the intermediate part 35b and the thickest part 35c formed on the igniter facing surface 35 of the iron core cover 34 are as follows. You may change to arbitrary dimensions according to design circumstances. Further, the iron core cover 34 is provided around the outer peripheral iron core 32 except for the connection surface with the central iron core 30 and the magnet 38. For example, the iron core cover 34 is lower than the height of the fixed wall 48 of the igniter facing surface 35. Without being provided with the iron core cover 34 at the position, the outer peripheral iron core 32 is exposed, the filling property of the mold resin 80 between the outer peripheral iron core 32 and the fixed wall 48 is improved, etc. It is.

The distance L3 between the thinnest portion 35a and the igniter 70 and the distance L4 between the intermediate portion 35b and the igniter terminal 72 are determined from the igniter facing surface 35 of the iron core cover 34 of the fixed wall 48. The distance between the iron core cover 34 and the igniter 70 may be changed to a distance that can further improve the filling property of the mold resin 80 by changing the dimension in the igniter 70 direction. Furthermore, as long as the fixed wall 48 is formed in at least a part between the igniter facing surface 35 and the igniter 70, the shape and formation position may be arbitrarily changed depending on the design circumstances.

Further, the case 40 has a shape having an opening surface on the upper surface in the vertical direction, but the igniter facing surface 35 of the iron core cover 34 is the thickest portion 35c from the opening surface with the filling direction of the mold resin 80 as the opening surface. As long as the intermediate portion 35b and the thinnest portion 35a are configured in this order, the intermediate portion 35b and the thinnest portion 35a may be arbitrarily changed depending on design circumstances. Further, the outer peripheral iron core 32 may be changed to, for example, a U-shaped outer peripheral iron core other than the square-shaped iron core.

Next, FIG. 11 is a perspective view of an ignition coil for an internal combustion engine according to a third embodiment of the present invention, FIG. 12 is a cross-sectional view taken along the line HH as viewed from the direction of the arrow (G) in FIG. FIG. 13 is an enlarged view of part I, FIG. 14 is a top view of the case of the ignition coil according to the third embodiment of the present invention, and FIG. 15 is a circuit diagram of the ignition coil according to the third embodiment of the present invention. Respectively.

11 to 15, the case 40 forming the outer shape of the ignition coil 90 is formed by a box-shaped integral molding having an opening surface on the upper surface in the vertical direction. Further, the case 40 is formed with a case fixing portion 42 for attaching and fixing the ignition coil 90 to an engine head (not shown). Furthermore, a high voltage tower 44 having a high voltage terminal 60 for supplying a secondary voltage to the spark plug 96 is formed on the bottom surface of the ignition coil 90 so as to protrude into a plug hole formed in the upper part of the engine. ing.

The ignition coil 90 includes an iron core 36 formed by laminating a plurality of thin plates and an I-shaped central iron core 30 and a U-shaped outer peripheral iron core 32, and an outer periphery of the central iron core 30. The primary coil 14 in which the primary winding 12 is wound about 100 turns around the outer periphery of the primary bobbin 10 molded with resin, and the outer periphery of the secondary bobbin 20 molded with resin on the outer periphery of the primary coil 14 The secondary winding 22 is composed of a coil portion of a secondary coil 24 in which the secondary winding 22 is wound about 8000 to 15000 turns. Further, the outer peripheral iron core 32 is disposed such that the magnetic path of the iron core 36 is perpendicular to the opening surface of the case 40.

Also, a magnet 38 for generating a magnetic flux in the opposite direction to the magnetic flux generated by the primary coil 14 in the magnetic path is provided at one end of the connecting surface of the central iron core 30 and the outer peripheral iron core 32. . Further, a secondary high voltage terminal 26 for supplying a secondary voltage to the high voltage terminal 60 is provided at one end of the secondary bobbin 20, and a primary voltage from the primary coil 14 is supplied to the other end. A secondary low-voltage terminal (not shown) is provided.

An igniter 70 for supplying an ignition signal to the primary coil 14 is provided in the case 40. The igniter 70 includes a switching element and a lead frame. The lead frame includes a base and a collector of the switching element, Each of the emitters is arranged as an igniter terminal 72 for connection to the outside. Further, a connector 46 having a connector terminal 62 for supplying a primary voltage from the battery 92 and an ignition signal from the ECU 94 is formed on the side surface of the case 40.

The connector terminal 62 connects a terminal connecting the battery 92 to the low voltage side of the primary coil 14 and the secondary coil 24, and connecting the igniter terminal 72 arranged on the base side of the igniter 70 from the ECU 94. The terminal is composed of a total of three terminals: the igniter terminal 72 arranged on the emitter side of the igniter 70 and the terminal connecting the outer peripheral iron core 32 to the ground. Further, the igniter terminal 72 disposed on the collector side of the igniter 70 is connected to the high voltage side of the primary coil 14.

Further, the connector terminal 62 and the igniter terminal 72 have a substantially flat metal terminal, and two of the connector terminal 62 and the igniter terminal 72 are led out in the same direction and are electrically connected to each other. They are connected using welding as is realized. Further, the connector terminal 62 and the igniter terminal 72 are led out in a direction perpendicular to the opening surface of the case 40, and the connector terminal 62 extends over the inner wall of the case 40 on the same surface as the connector 46 formed on the case 40. Is arranged.

Further, a ground terminal wiring groove 50 for inserting the connector terminal 62 connecting the ground from the outer peripheral iron core 32 is formed on the surface of the inner bottom surface of the case 40.

Further, the periphery of the outer peripheral iron core 32 excluding the connection surface with the central iron core 30 and the magnet 38 is used for preventing rust of the outer peripheral iron core 32 formed of polybutylene terephthalate (hereinafter referred to as “PBT”). The iron core cover 34 is covered. Further, a fixing wall 48 for fixing the igniter 70 is formed between the igniter facing surface 35 of the iron core cover 34 on the inner bottom surface of the case 40 and the igniter 70, and the fixing wall 48 is an inner bottom surface of the case 40. From the height of the igniter 70 in the vertical direction.

The fixed wall 48 is formed between the igniter facing surface 35 of the iron core cover 34 and the igniter 70 so as to avoid the ground terminal wiring groove 50.

The igniter-facing surface 35 of the iron core cover 34 is formed in three types of thicknesses, a thinnest part 35a, an intermediate part 35b, and a thickest part 35c, and the axial direction of the coil part of the iron core cover 34 The coil facing portion 34a positioned horizontally is formed with the same thickness as the thickest portion 35c of the iron core cover 34. Further, the intermediate portion 35b is formed at a position higher than the vertical height of the fixed wall 48, and the thickest portion 35c is formed at a position higher than the vertical height of the igniter 70.

The case 40 is filled with a mold resin 80 that realizes electrical insulation of the ignition coil 90 and physical fixation of each member. Further, the mold resin 80 is filled up to the vicinity of the opening surface of the case 40, and the central iron core 30, the primary coil 14, and the secondary coil 24 are formed in the vicinity of the opening surface of the case 40. The coil facing portion 34a of the iron core cover 34 is provided at a position higher than the resin surface 82 by a length L5.

With the above configuration, the outer peripheral iron core 32 is arranged so that the magnetic path of the iron core 36 is perpendicular to the opening surface of the case 40, and the coil facing portion 34a of the iron core cover 34 is formed of the resin surface. Since it is provided at a position higher by L5 length than 82, the lateral L8 dimension of the case 40 can be suppressed, the case 40 can be miniaturized, and the amount of the mold resin 80 filled in the case 40 can be reduced. It can also be reduced. Further, by covering the periphery of the outer peripheral iron core 32 excluding the connection surface with the central iron core 30 and the magnet 38 with the iron core cover 34, the outer peripheral iron core provided at a position higher than the resin surface 82. 32 rust can be prevented. Further, the coil facing portion 34a of the iron core cover 34 is formed with the thickness of the iron core cover 34 similar to that of the thickest portion 35c, thereby preventing the occurrence of defects due to water, dust, etc. it can.

Further, by forming the fixing wall 48 for fixing the igniter 70 between the igniter facing surface 35 of the iron core cover 34 on the inner bottom surface of the case 40 and the igniter 70, the fixing wall 48 is formed during manufacturing. Fixing the igniter 70 eliminates the need to fix the igniter 70 with a jig. Further, the igniter facing surface 35 of the iron core cover 34 has three types of thicknesses, the thinnest portion 35a, the intermediate portion 35b, and the thickest portion 35c. By forming it at a position higher than the height in the vertical direction, the distance L6 between the thinnest portion 35a and the igniter 70 is increased, and the gap between the thinnest portion 35a and the igniter 70 is widened. The filling property of the mold resin 80 between the portion 35a and the fixed wall 48 can be improved.

The thickest portion 35c is formed at a position higher than the vertical height of the igniter 70, so that the distance L7 between the intermediate portion 35b and the igniter terminal 72 is increased, and the intermediate portion 35b and the igniter Since the gap between the terminals 72 is widened, the filling property of the mold resin 80 between the intermediate portion 35b and the igniter 70 can be improved.

As a modified example of the third embodiment, the iron core cover 34 may be formed of polyethylene terephthalate, elastomer, nylon, or the like, and the igniter facing surface 35 of the iron core cover 34 has at least two types of thickness. If necessary, it can be changed as appropriate. The fixed wall 48 can be appropriately changed as long as the fixed wall 48 is formed with a height of ½ or less of the vertical height of the igniter 70. Further, the intermediate portion 35b formed on the igniter facing surface 35 of the iron core cover 34 may be changed to any height as long as it is higher than the vertical height of the fixed wall 48. The thickest portion 35c formed on the igniter facing surface 35 of the iron core cover 34 may be changed to any height as long as it is higher than the vertical height of the igniter 70.

Further, the thickness dimension of the coil facing portion 34a of the iron core cover 34 and the thicknesses of the thinnest portion 35a and the intermediate portion 35b and the thickest portion 35c formed on the igniter facing surface 35 of the iron core cover 34. The dimension may be changed to an arbitrary dimension depending on the design circumstances. Further, the iron core cover 34 is provided around the outer peripheral iron core 32 except for the connection surface with the central iron core 30 and the magnet 38. For example, the iron core cover 34 is lower than the height of the fixed wall 48 of the igniter facing surface 35. Without being provided with the iron core cover 34 at the position, the outer peripheral iron core 32 is exposed, the filling property of the mold resin 80 between the outer peripheral iron core 32 and the fixed wall 48 is improved, etc. It is.

The distance L6 between the thinnest portion 35a and the igniter 70 and the distance L7 between the intermediate portion 35b and the igniter terminal 72 are determined from the igniter facing surface 35 of the iron core cover 34 of the fixed wall 48. The distance between the iron core cover 34 and the igniter 70 may be changed to a distance that can further improve the filling property of the mold resin 80 by changing the dimension in the igniter 70 direction. Furthermore, as long as the fixed wall 48 is formed in at least a part between the igniter facing surface 35 and the igniter 70, the shape and formation position may be arbitrarily changed depending on the design circumstances.

In addition, as long as at least a part of the coil facing portion 34a of the iron core cover 34 is provided at a position higher than the resin surface 82, the dimension of the length L5 may be changed to an arbitrary length depending on design circumstances. Further, although the case 40 has a shape having an opening surface on the upper surface in the vertical direction, the igniter facing surface 35 of the iron core cover 34 is the thickest portion 35c from the opening surface with the filling direction of the mold resin 80 as the opening surface. As long as the intermediate portion 35b and the thinnest portion 35a are configured in this order, the intermediate portion 35b and the thinnest portion 35a may be arbitrarily changed depending on design circumstances.

10: 1 primary bobbin
12: Primary winding
14: Primary coil
20: Secondary bobbin
22: Secondary winding
24: Secondary coil
26: Secondary high-voltage terminal
30: Central iron core
32: Outer iron core
34: Iron core cover
34a: Coil facing part
35: Igniter facing surface
35a: Thinnest part
35b: Middle part
35c: Thickest part
36: Iron core
38: Magnet
40: Case
42: Case fixing part
44: High-pressure tower
46: Connector
48: Fixed wall
50: Ground terminal wiring groove
60: High voltage terminal
62: Connector terminal
70: Igniter
72: Igniter terminal
80: Mold resin
82: Resin surface
90: Ignition coil
92: Battery
94: ECU
96: Spark plug

Claims (5)

A case, and at least a part of an iron core composed of a central iron core and an outer peripheral iron core is accommodated in the case,
A primary coil in which a primary winding is wound around a primary bobbin and a secondary coil in which a secondary winding is wound around a secondary bobbin are accommodated in the case.
An igniter for supplying an ignition signal to the primary coil in the case;
In the ignition coil for an internal combustion engine in which the coil housing portion in the case is filled with mold resin,
A resin iron core cover is provided on at least a part of the periphery of the outer peripheral iron core,
Forming a fixed wall between the iron core cover in the case and the igniter;
An ignition coil for an internal combustion engine, wherein the iron core cover has at least two types of thickness on a surface of the iron core cover facing the fixed wall. 2. The ignition coil for an internal combustion engine according to claim 1, wherein the fixed wall has a height that is ½ or less of a vertical height of the igniter. 3. The ignition for an internal combustion engine according to claim 1, wherein a thickest portion of a surface of the iron core cover facing the fixed wall is disposed at a position higher than a vertical height of the igniter. coil. The outer peripheral iron core is arranged such that the magnetic path of the iron core is oriented in a direction perpendicular to the opening surface of the case,
4. The ignition coil for an internal combustion engine according to claim 1, wherein the coil facing portion of the outer peripheral iron core is provided at a position higher than a resin surface of the mold resin. 5. 5. The thickness of the iron core cover provided in the coil facing portion of the outer peripheral iron core is wider than the thickness of the thinnest portion of the surface of the iron core cover facing the fixed wall. 2. An ignition coil for an internal combustion engine according to 1.

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