JP2008166582A - Ignition coil for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ignition coil having a reduced reliability and presenting a miniaturized structure with good reliability.
[Solution]
The case is disposed outside the plug hole, and the case has at least two openings, a coil insertion opening for inserting each coil and a high-pressure tower insertion opening for inserting the high-voltage tower. The coil insertion opening is a high-pressure tower. The winding axis of the primary coil and the secondary coil is substantially perpendicular to the axial direction of the high-voltage tower, and the entire outer circumferential surface of the secondary coil and the case. An ignition coil characterized in that the distance to the inner wall is substantially the same.
[Selection] Figure 1

Description

  The present invention relates to an ignition coil for an internal combustion engine, and more particularly to a structure for reducing the size of an ignition coil.

  Recent internal combustion engines for automobiles have conflicting demands for high output with lean combustion in consideration of the global environment, and the engine is required to be smaller in order to reduce vehicle weight and contribute to fuel efficiency in order to improve automobile efficiency. By reducing the height direction, each wiring and component can be reduced. Accordingly, there is a demand for miniaturization of the ignition coil, and in order to maintain the performance of the ignition coil while corresponding to the miniaturization, it is necessary to design a magnetic circuit and component arrangement with high efficiency in a limited space. FIG. 10 is a top view of a conventional ignition coil for an internal combustion engine. FIG. 11 is a vertical sectional view taken along line AA in FIG. FIG. 12 is a BB longitudinal sectional view of FIG. 13 is a CC longitudinal sectional view of FIG. 10 attached to the engine. FIG. 14 is a punching view of a silicon steel thin plate constituting a U-shaped outer peripheral side core and a T-shaped central side core of an ignition coil for an internal combustion engine according to the prior art.

  10 to 14, the ignition coil 10 to which the prior art is applied has a primary coil 20 in which a primary conductor is wound around a primary bobbin 21 and a secondary conductor is wound around a secondary bobbin 31 on the outer periphery thereof. The secondary coil 30 is disposed, and the primary coil 20 and the secondary coil 30 are housed in a case 40 made of polybutylene terephthalate resin (hereinafter referred to as PBT) having a large coil insertion opening 47. The primary conductor end of the primary coil 20 is electrically connected to a primary connector terminal 51 provided in the primary connector 50, and the high-voltage side of the secondary coil 30 has a cylindrical protrusion 2 at its tip. The secondary bobbin terminal 32 is electrically connected to a high voltage terminal 70 that is a screw via a high voltage lead terminal 60 described later.

  The low voltage side of the secondary coil 30 is electrically connected to the primary connector terminal 51. In the case 40, the primary coil 20, the secondary coil 30, and a center side core 81 and an outer side core 82, which will be described later, are embedded and integrated by injection-hardening an epoxy resin 96 as an insulating material. ing. The case 40 integrally has a high voltage tower 41 that distributes a high voltage generated by the secondary coil 30 on the side opposite to the opening surface. The high voltage tower 41 is electrically connected to the outside of the ignition coil 10. The high-voltage terminal 70, which is a screw to be connected, is provided. Further, a T-shaped central core 81 formed by laminating thin sheets of silicon steel plates is inserted into the internal space of the primary bobbin 21, and the thin sheets of silicon steel plates forming a closed magnetic circuit are laminated with the central core 81. A U-shaped outer peripheral core 82 formed in this manner is positioned outside the coil.

  The central core 81 and the outer peripheral core 82 have a core shape in which the cross section in the magnetic path direction is a quadrangle, and the stacking directions of the cores are arranged in the same direction. The joint surface between the central core 81 and the outer core 82 is a flat surface, and one end of the central core 81 serving as the joint surface with the U-shaped outer core 82 has a cross section in the magnetic path direction from the other end. It has a substantially T-shaped portion that gradually widens and widens. Further, in the substantially T-shaped portion, a magnet 90 having a bonding area smaller than the area of the substantially T-shaped portion of the central core as a magnet for applying a reverse bias of the magnetic field generated in the primary coil 20 is a gap. It is installed without. Further, as shown in FIG. 14, thin pieces of silicon steel plates constituting the T-shaped central core 81 and the U-shaped outer peripheral core 82 are pulled out of the silicon steel sheet 80 and laminated, respectively, and the T-shaped central side. The core 81 and the U-shaped outer peripheral core 82 are formed. Although not shown, the core is connected to GND so as not to charge the core to suppress radio noise during coil operation. Further, the core is covered with a core cover 85 made of an elastic material such as an elastomer in order to reduce a difference in linear expansion coefficient with the epoxy resin as a crack prevention with the core as a base point.

  The secondary coil 30 is provided with a receiving portion 95 that contains a radio noise suppression resistor 94 that is formed in a cylindrical shape and suppresses radio noise during coil operation. Electrically connected. The electrical connection for distributing the high voltage generated in the secondary coil 30 to the high voltage terminal 70, which is a screw, is provided with a high voltage lead terminal 60 having a plate shape made of a conductor and provided with through holes at both ends. In order to connect the high-voltage lead terminal 60 and the high-voltage terminal 70 which is a screw, the high-voltage lead terminal 60 is subjected to burring / tapping to make a pilot hole and stretch-flange into a cylindrical shape. , Mechanically screwed.

  The secondary bobbin terminal 32 has a cylindrical protrusion at the tip and is formed of a conductive material, and is attached to the high-pressure side of the secondary bobbin 31. The secondary bobbin terminal 32 and the high-voltage lead terminal 60 are connected to each other by projecting a cylindrical protrusion at the tip of the secondary bobbin terminal 32 through a through-hole provided in the high-voltage lead terminal and projecting from the through-hole. Next, the bobbin terminal is bent to form a bent portion, and then the bent portion is electrically and mechanically connected by soldering.

  A plug boot 98 that is connected to an ignition plug (not shown) made of an elastic material such as rubber is attached to the outside of the high-pressure tower portion 41, and the ignition coil 10 is fixed to the engine head 99.

  The above-described conventional ignition coil 10 is an ignition coil that supplies a high voltage to an ignition plug. When an ignition signal is input from an ignition signal generation circuit (not shown), a current flows from a battery power source (not shown) into the primary coil 20 to generate a magnetic field. The generated magnetic field is held in the cores 81 and 82. Next, when the ignition signal is cut off, the current flowing through the primary coil 20 is also cut off, and a high voltage corresponding to the turn ratio of the primary coil 20 and the secondary coil 30 is excited in the secondary coil 30. Electric power is distributed from the secondary coil 30 to a spark plug (not shown) that is electrically connected via a high voltage terminal 70 that is a screw and a spring 97 that is connected to the high voltage terminal 70.

Further, in Patent Document 1 (Japanese Patent Laid-Open No. 2001-23839), the case has a funnel-shaped lower part that follows the lower part of the ball shape to accommodate the lower part of the ball-shaped secondary coil part, and a part of the case is attached to the engine. An ignition coil is disclosed which is adapted to be housed in a plug hole at the time.
JP 2001-23839 A

  However, in the said structure, since the lamination direction of the thin plate of the silicon steel plate of the said center side core and the said outer peripheral side core is comprised in the same direction, the height direction of a core is high. Further, since the core is covered with an elastic material such as an expensive elastomer, the manufacturing cost is high. Although the thin sheet piece of the silicon steel plate constituting the U-shaped outer peripheral core is pulled out from the sheet of silicon steel plate, there is a lot of punching loss, and the core material is wasted. In addition, since the secondary coil is provided with a housing portion that accommodates a radio noise suppression resistor and is electrically connected to the radio noise suppression resistor, a large number of processing steps can be achieved by designing the housing portion in an extra manner. Was bulky. Further, the epoxy resin 96 is injected and cured into the coil insertion opening 47, but the side surface of the secondary coil 30 may be exposed due to variations in the injection amount. Further, since the high-voltage lead terminal and the high-voltage terminal are connected by screw connection, burring to the high-voltage lead terminal and screw connection man-hours are required, and many processing man-hours are increased. Furthermore, the connection between the secondary bobbin terminal and the high-voltage lead terminal requires a large number of assembly steps as described above, and also contaminates the global environment by using solder. Moreover, in patent document 1 (Unexamined-Japanese-Patent No. 2001-23839), although a part of coil part is arrange | positioned inside a plug hole, it is not applied in the ignition coil which arrange | positions a coil part outside a plug hole. Accordingly, an object of the present invention is to solve the above problems and to provide an ignition coil for an internal combustion engine that presents a miniaturized structure and has good reliability that does not pollute the global environment.

  In order to solve the above-mentioned problems, in claim 1 of the present invention, a rod-shaped central core, a primary coil wound around the central core in the coaxial direction, and a coaxial coil of the primary coil outside the primary coil. Secondary coils that are wound in a direction, each coil is provided with a bobbin that serves as a winding axis, and an outer core that is provided so as to form a closed magnetic path at both ends of the central core. A part of the primary coil and the secondary coil are disposed in a space formed by the case, a case for accommodating the primary coil and the secondary coil, and a case for supplying a high voltage from the secondary coil to the spark plug In an ignition coil having a high-pressure tower portion having a shaft in a more projecting direction and injecting and hardening a filling resin inside the case, the case is disposed outside the plug hole, and each coil is inserted into the case Having at least two openings, a coil insertion opening and a high-pressure tower insertion opening for inserting the high-pressure tower, wherein the coil insertion opening is provided in a direction substantially perpendicular to the axial direction of the high-pressure tower, The winding axis of the primary coil and the secondary coil is substantially perpendicular to the axial direction of the high-voltage tower, and the distance between the entire axial outer peripheral surface of the secondary coil and the case inner wall is substantially the same. Ignition coil.

  According to a second aspect of the present invention, the case and the high-voltage tower portion are integrated by fitting, the secondary bobbin is provided with a secondary bobbin terminal for taking out a high voltage directly from a secondary coil, and the high-voltage tower portion has the above-mentioned A high voltage terminal for distributing a high voltage from the secondary coil to the outside, and a high voltage lead terminal for electrically connecting the high voltage of the secondary coil to the high voltage terminal; 2. The ignition coil according to claim 1, wherein the secondary bobbin terminal and the high-voltage lead terminal are arranged in a positional relationship that can be connected and fixed at the same time.

  According to a third aspect of the present invention, the high-pressure tower section has a high-pressure tower insertion section slightly larger in diameter than the inner diameter of the high-pressure tower insertion opening section of the case, and the high-pressure tower insertion section is inserted toward the high-pressure tower insertion opening section. Thus, the case and the high-pressure tower portion are integrated by fitting to form an ignition coil for an internal combustion engine according to claim 1.

  According to a fourth aspect of the present invention, the high-voltage terminal and a high-voltage lead terminal that is electrically connected to the high-voltage terminal are arranged inside the high-voltage tower, and the high-voltage tower is arranged inside the plug hole. The ignition coil according to claim 1.

  According to a fifth aspect of the present invention, an axis of the high-voltage tower portion and an end of the high-voltage lead terminal on the side connected to the secondary bobbin terminal have a certain distance in a direction perpendicular to the axis of the high-voltage tower portion. The ignition coil according to claim 2, wherein the ignition coil is provided.

  According to a sixth aspect of the present invention, in the ignition coil for an internal combustion engine according to the second aspect, the high-voltage lead terminal is made of a plate-like conductive material and has a through hole at one end.

  According to a seventh aspect of the present invention, the high-voltage lead terminal is a terminal formed of a rod-shaped conductive material and having a substantially conical spiral portion with one end portion having a diameter increasing toward the tip end. 2. An ignition coil for an internal combustion engine as described in 2.

  Further, in the present invention, the high-voltage tower section includes a radio noise suppression resistor that suppresses radio noise during coil operation, an inductor having an inductance component, and an erroneous ignition prevention diode that prevents erroneous ignition. 2. An ignition coil for an internal combustion engine according to claim 1, wherein at least one kind is arranged.

  According to a ninth aspect of the present invention, there is provided a plug boot made of an elastic material such as rubber attached to the outside of the high-pressure tower section, and the outer diameter of the high-pressure tower insertion section is equal to the outer diameter of the cylindrical section of the plug boot. 2. An ignition coil for an internal combustion engine according to claim 1, wherein the ignition coil is the same or at least small in diameter.

  Further, in claim 10, the seal between the high-pressure tower insertion portion of the high-pressure tower portion and the high-pressure tower insertion opening portion of the case is a seal that interposes welding, an adhesive, an O-ring, or the like. An ignition coil for an internal combustion engine according to claim 3, wherein

  In the eleventh aspect, the case includes a primary bobbin engagement hole that engages with a part of the primary bobbin on a side opposite to the coil insertion opening, and the central core is provided inside the primary bobbin. 2. The closed magnetic circuit is formed by holding the central core end part, exposing a part of the primary bobbin engagement hole, and disposing the outer peripheral core on the outer periphery of the central core. It is set as the ignition coil for internal combustion engines of description.

  Further, in claim 12, the center core is a T-type or I-type core, and the outer peripheral core is a U-shaped core formed by combining two L-type cores. A coil.

  According to a thirteenth aspect of the present invention, there is provided the ignition coil for an internal combustion engine according to the first aspect, wherein the outer peripheral core is covered with a resin or rubber cover on the outer periphery.

  Further, in claim 14, a locking part is provided in a part of the cover, and a key-like part is provided in a part of the case so as to be fitted to the locking part. Ignition coil.

  Further, in the fifteenth aspect of the invention, the internal combustion engine ignition coil according to the first aspect, wherein the outer peripheral core is formed by stacking silicon steel thin plates of the central core in a direction perpendicular to the stacking direction. .

  According to a sixteenth aspect of the present invention, there is provided the ignition coil for an internal combustion engine according to the first aspect, wherein the number of the central core and the outer peripheral core is equal.

  According to a seventeenth aspect of the present invention, there is provided an internal combustion engine ignition coil characterized by combining at least two of the first to sixteenth aspects.

  By applying the configuration of the present invention as described above, it is possible to provide a small and high performance ignition coil.

  FIG. 1 is a top view of an internal combustion engine ignition coil according to a first embodiment of the present invention. FIG. 2 is a vertical sectional view taken along line AA in FIG. FIG. 3 is a BB longitudinal sectional view of FIG. FIG. 4 is a punched view of a silicon steel sheet constituting the L-shaped outer peripheral core A, the L-shaped outer peripheral core B, and the T-shaped central core of the ignition coil for the internal combustion engine of the present invention. FIG. 5 is a CC longitudinal sectional view of FIG. 1 attached to the engine. FIG. 6 is an assembly diagram of the radio noise suppression resistor and the high voltage lead terminal of the ignition coil for the internal combustion engine according to the technique of the present invention. FIG. 7 is an assembly diagram of Modification 1 of the ignition coil for an internal combustion engine according to the technique of the present invention. FIG. 8 is a longitudinal sectional view of a second modification of the ignition coil for an internal combustion engine according to the technique of the present invention. FIG. 9 is a longitudinal sectional view of an ignition coil for an internal combustion engine according to the second embodiment of the technology of the present invention.

  The ignition coil 100 of the present invention shows only the difference from the prior art. 1 to 4, the ignition coil 100 for an internal combustion engine according to the first embodiment of the present invention includes a primary coil 120 and a secondary coil 130, and the primary coil 120 and the secondary coil 130 are made of PBT resin. The case 140 is housed. The case 140 is formed integrally with a primary connector 150 having a primary connector terminal 151, and the side surface portion of the case 140 is arranged so that the primary connector terminal 151 is in the same direction as the axial direction of the central core. Is arranged.

  Further, as shown in FIG. 4, the thin pieces of silicon steel plate constituting the center side core 181 and the L-shaped outer peripheral sides 182 and 183 are pulled out from the silicon steel sheet 180 and laminated to be respectively L-shaped outer peripheral core 182. 183 and the central core 181. The outer peripheral side core 183 has a locking portion 183a. It is covered with a core cover 185 made of PBT resin similar to the material of the case 140 or made of insulating rubber. The case 140 is formed with a key part 146, and the core cover 185 is formed with a locking part 183 a that locks the key part 146. The outer peripheral core 183 is held by the case by the key part 146 and the locking part 183a, and contributes to the improvement of assembly.

  The case 140 is provided with a primary bobbin engagement hole 142 that engages with a part of the primary bobbin 121 on the side opposite to the coil insertion opening 147, and the center core 181 is disposed inside the primary bobbin 121. The center side core end portion is partially exposed from the primary bobbin engagement hole 142, and the outer peripheral side cores 182 and 183 are arranged on the outer periphery of the center side core 181 to constitute a closed magnetic circuit. The central core 181 and the outer peripheral cores 182 and 183 have a core shape with a quadrilateral cross section in the magnetic path direction, and the stacking directions of the cores are arranged in different vertical directions. Further, the number of laminated cores 181 and outer cores 182 and 183 is equal, and the same number of sheets are punched from the same silicon steel sheet 180. Thus, the silicon steel sheet 180 can be used effectively. The cross section of the center side core 181 in the magnetic path direction has a long side and a short side, and the short side is arranged in the height direction of the ignition coil 100 so that the primary coils 120 and 2 arranged on the outer peripheral side are arranged. The height of the secondary coil 130 can be suppressed, and the height of the ignition coil 100 can be suppressed. In addition, one end of the center side core 181 serving as a joint surface with the outer peripheral side cores 182 and 183 has a substantially T-shaped portion that widens toward the end so that the cross section in the magnetic path direction becomes gradually larger than the other end. In addition, a magnet 190 having a bonding area smaller than the area of the substantially T-shaped portion of the central core 181 is provided on the substantially T-shaped portion as a magnet 190 for applying a reverse bias to the magnetic field generated in the primary coil 120. It is installed without gaps. Further, the case 140 has a high voltage tower 141 for distributing a high voltage generated by the secondary coil 130. The high voltage tower 141 has an axis in a direction perpendicular to the case surface and is located with respect to the case surface. Protrusively arranged.

  In FIG. 5, the ignition coil 100 arranged and fixed outside the plug hole 199 a of the engine head 199 has a case 140 with a coil insertion opening 147 into which each coil is inserted with respect to the axial direction of the high-voltage tower 141. The primary coil 120 is formed of a hollow resin and has a primary bobbin 121 having an opening having a large diameter at one end so as to accommodate the substantially T-shaped portion of the central core 181. A primary conductor is wound around the outer periphery. The large opening end 121a at one end of the primary bobbin 121 is configured to have the same length as the end of the coil insertion opening 147 of the case when housed in the case 140. A secondary coil 130 around which a secondary conducting wire is wound is disposed on the outer periphery of the primary coil 120. A secondary bobbin terminal 132 is mounted on the high voltage side end of the secondary coil 130, and the coil insertion opening is arranged such that the winding axis of the secondary coil 130 is substantially perpendicular to the axial direction of the high voltage tower. The primary coil 120 and the secondary coil 130 are inserted from the portion 147 and disposed in the case 140. At this time, the end of the primary bobbin 121 opposite to the opening end 121a is partially exposed from the primary bobbin engagement hole 142, but the end opposite to the opening end 121a is engaged with the primary bobbin engagement. The case 142 is sealed to isolate the inside of the case. Further, since the inner wall of the case 140 is configured to have an optimum distance substantially coincident with the outer peripheral surface in the axial direction of the secondary coil, the height of the ignition coil 100 can be reduced. The secondary bobbin terminal 132 has a cylindrical shape that suppresses radio noise during coil operation via a high-voltage lead terminal 161 described later, and both ends thereof are connected to a radio noise suppression resistor 194 formed of conductors 194a and 194b. It is electrically connected to a spark plug (not shown) via a spring 197.

  The high-voltage tower 141 is formed of a member different from the case 140 and is provided with a conduction hole that penetrates the outside and the inside. The inside of the high-voltage tower 141 is an end of the conductor 194b at the lower end of the radio noise suppression resistor 194. It arrange | positions so that a part may be exposed from the said conduction hole front-end | tip. As described above, since the high-voltage tower 141 is formed of a separate member from the case 140, the radio noise suppression resistor 194 can be easily arranged. The case 140 has a high-pressure tower insertion opening 143 into which the high-pressure tower 141 is inserted and fitted, and the high-pressure tower 141 has an insertion 145 having a diameter slightly larger than the inner diameter of the opening. By inserting the insertion portion 145 toward the high-pressure tower insertion opening 143, the high-pressure tower portion 141 and the case 140 are fitted and assembled. At this time, the insertion portion 145 and the high-pressure tower insertion opening portion 143 are fitted to perform sealing, but an adhesive, an O-ring or the like is interposed in the fitting portion, or welding is performed in a later process. May be performed. When the case 140 and the high voltage tower 141 are fitted, the secondary bobbin terminal and the high voltage lead terminal 161 can be connected and fixed at the same time.

  Further, the resin is integrated by injecting and curing epoxy resin 196 from the coil insertion opening 147 to the outer peripheral side of the primary bobbin 121. Accordingly, the epoxy resin 196 is not injected into the central core 181 at all. A plug boot 198 that holds a spark plug (not shown) made of an elastic material such as rubber is mounted outside the high-pressure tower 141. At this time, the outer diameter of the insertion portion 145 is preferably the same as or at least smaller than the outer diameter of the tube portion of the plug boot 198. As a result, the high-pressure tower 141 having the insertion portion 145 can be accommodated in the plug hole as much as possible, so that the height of the ignition coil 100 can be reduced.

  Further, as shown in FIG. 6, the high-voltage lead terminal 161 is made of a conductive material having a plate-like L-shaped bent portion, and has a through hole 161a at the center of one end, and the inner periphery of the through hole 161a suppresses the radio noise. By engaging with the outer periphery of the conductor end 194a at the rear end of the resistor 194, the high voltage lead terminal 161 is fixed inside the high voltage tower 141, and the radio noise suppression resistor 194 and the high voltage lead terminal 161 are connected to each other. Electrically connected. The distance between the one end of the high-voltage lead terminal 161 and the other end in the direction perpendicular to the high-voltage tower axis is a fixed distance, and the high-voltage tower axis and the other tip of the high-voltage lead terminal 161 are separated from each other. Be placed.

  Further, as a first modification of the first embodiment, the high-voltage lead terminal is formed of a rod-shaped conductive material as shown in FIG. 7, and has a substantially conical spiral portion 162a having a tip portion that increases in diameter toward the tip. Alternatively, a high voltage lead terminal 162 may be used. The inner periphery of the substantially conical upper spiral portion 162a of the high voltage lead terminal 162 is engaged with the outer periphery of the conductor end portion 194a at the rear end of the radio noise suppression resistor 194, so that the high voltage lead terminal 162 is connected to the high voltage tower portion. The radio noise suppression resistor 194 and the high voltage lead terminal 162 are electrically connected to each other. In addition, the distance in the direction perpendicular to the high-voltage tower axis between one tip of the high-voltage lead terminal 162 and the other tip connected to the secondary bobbin terminal is a fixed distance, and the high-voltage tower axis and the high-voltage lead The other end of the terminal 162 is spaced apart.

  The high-voltage tower 141 contains a radio noise suppression resistor 194 that suppresses radio noise during coil operation. For example, an inductance component can be used as long as radio noise during coil operation can be suppressed. May be accommodated, or both the radio noise suppression resistor and the inductor may be accommodated. Further, a high voltage diode that prevents ignition at an unexpected ignition timing may be arranged. At least two types of the radio noise suppression resistor, the inductor, and the high voltage diode may be accommodated.

  Although not shown, the center-side core 181 has a substantially T-shaped shape in which one end of the center-side core 181 serving as a joint surface with the outer-side cores 182 and 183 gradually expands in cross section in the magnetic path direction from the other end. The center-side core 181 serving as a joint surface with the outer peripheral side cores 182 and 183 is an I-type center-side core having the same cross section in the magnetic path direction at the other end. Also good. In this case, a magnet is not attached to the joint surface between the central core and the outer core, and the joint surface between the I-type central core and the outer core may have an equally spaced air gap. .

  As a second modification of the first embodiment, as shown in FIG. 8, the ignition coil 100 may have the following configuration when the radio noise suppression resistor 194 is not provided. A high voltage terminal 270 having a convex portion 270a at the top is disposed inside the high voltage tower portion 141 formed of a member different from the case 140, and is fitted with the convex portion 270a and has a plate shape having an L-shaped bent portion. A high voltage lead terminal 261 is arranged. The high voltage terminal 270 is electrically connected to the spring 297. Note that the distance in the direction perpendicular to the high-voltage tower axis between the one tip of the high-voltage lead terminal 261 and the other tip connected to the secondary bobbin terminal is a fixed distance, and the high-voltage tower axis and the high-voltage lead The other tip of the terminal 261 is spaced apart.

  In the above-described embodiment, the ignition coil 100 constituted by a member different from the high-pressure tower portion 141 and the case 140 has been described. However, the ignition coil 300 for an internal combustion engine according to the second embodiment of the present invention is as follows. It can also be configured. As shown in FIG. 9, the ignition coil 300 has a configuration in which a high-voltage tower portion and a case are integrally formed. The case 340 includes a high-voltage tower 341 that projects downward and is integrally formed. Inside the high-voltage tower 341, a radio noise suppression resistor 194 that is cylindrical and has both ends formed of conductors 194a and 194b is disposed. A spring 397 connected to the radio noise suppression resistor 194 is disposed at the tip of the high voltage tower 341. The radio noise suppression resistor 194 is connected to a high voltage lead terminal 161 electrically connected to the high voltage side of the secondary coil, and the high voltage of the secondary coil is a high voltage lead terminal 361, a radio noise suppression resistor 194, Power is distributed to a spark plug (not shown) via a spring 397. Also in the case of the ignition coil 300, the radio noise suppression resistor 194 and the high voltage lead terminal 361 are disposed in the high voltage tower portion inside 341, so that the height can be reduced compared to the conventional ignition coil. . Note that the distance in the direction perpendicular to the high-voltage tower axis between one tip of the high-voltage lead terminal 361 and the other tip on the side connected to the secondary bobbin terminal is a fixed distance, and the high-voltage tower axis and the high-voltage lead The other tip of the terminal 361 is spaced apart.

  As described above, since the axial centers of the high-voltage tower portions 141 and 341 and the other tip of the high-voltage lead terminals 161, 261, and 361 connected to the secondary bobbin terminals are spaced apart from each other, the plug hole 199a The ignition coils 100 and 300 which are disposed and fixed outside the plug can be disposed immediately above the plug hole 199a. For this reason, in an internal combustion engine in which a cam or the like is arranged on the upper part of the engine head, the space for fixing the ignition coil around the plug hole becomes scarce. However, by adopting the ignition coil to which the configuration of the present invention is applied, the plug hole The ignition coil can be easily fixed immediately above.

  As described above, the embodiment of the present invention has been described based on the gist of the present invention. However, it is possible to reduce the number of assembling steps, present a miniaturized structure that suppresses the height, and has good reliability without polluting the global environment. The combination, size, position, and material of the ignition coil are not particularly limited as long as the ignition coil can be provided. That is, various modifications can be made without departing from the spirit of the present invention.

It is an upper view which comprises the ignition coil for internal combustion engines of Example 1 of the technique of this invention. It is AA longitudinal cross-sectional view of FIG. FIG. 3 is a BB vertical sectional view of FIG. 2. FIG. 4 is a punching view of a silicon steel sheet constituting an L-shaped outer peripheral core A, an L-shaped outer peripheral core B, and a T-shaped central core of an ignition coil for an internal combustion engine according to the technique of the present invention. It is CC longitudinal cross-sectional view of FIG. 1 with which the engine was mounted | worn. It is an assembly drawing of the resistance for radio noise suppression and the high voltage lead terminal of the ignition coil for the internal combustion engine of the technology of the present invention. It is an assembly drawing of the modification 1 of the ignition coil for internal combustion engines of the technique of this invention. It is a longitudinal cross-sectional view of the modification 2 of the ignition coil for internal combustion engines of the technique of this invention. It is a longitudinal cross-sectional view of the ignition coil for internal combustion engines of Example 2 of the technique of this invention. It is a top view which comprises the ignition coil for internal combustion engines of a prior art. It is AA longitudinal cross-sectional view of FIG. It is BB longitudinal cross-sectional view of FIG. It is CC longitudinal cross-sectional view of FIG. 10 with which the engine was mounted | worn. It is a punching figure of the silicon steel thin plate which comprises the U-shaped outer peripheral side core and T type | mold center side core of the ignition coil for internal combustion engines of a prior art.

Explanation of symbols

10, 100, 300 Ignition coil 20, 120 Primary coil 21 121 Primary bobbin 30, 130 Secondary coil 31, 131 Secondary bobbin 40, 140, 340 Case 41, 141 High voltage tower 47, 147 Coil insertion opening 50 , 150 Primary connector 51, 151 Primary connector terminal 60, 161, 162, 261, 361 High voltage lead terminal 70, 270 High voltage terminal 80, 180 Sheet 81, 181 Center side core 82, 182, 183 Outer side core 85, 185 Core cover 90, 190 Magnet 94, 194 Radio noise suppression resistor 95 Housing portion 96, 196, 396 Epoxy resin 97, 197, 297, 397 Spring 98, 198, 398 Plug boot 99, 199 Engine head 142 Primary bobbin engagement Hole 143 High-pressure tower insertion opening 145 High voltage tower insertion part 146 Key part 185 Core cover 183a Locking part 194a, 194b Conductor 199a Plug hole

Claims (17)

  A rod-shaped central core, a primary coil wound around the central core in the coaxial direction, and a secondary coil outside the primary coil and wound around the primary coil in the coaxial direction. Each bobbin serving as a winding shaft is provided, and an outer peripheral core is provided at both ends of the central core so as to form a closed magnetic path, and one of the primary coil and the secondary coil is formed in a space formed by the central core and the outer core. A case for housing the primary coil and the secondary coil, and a high voltage tower having a shaft in a direction protruding from the case by supplying a high voltage from the secondary coil to the spark plug. In the ignition coil in which filled resin is injected and cured, the case is disposed outside the plug hole, and the coil insertion opening for inserting each coil and the high-voltage tower portion are inserted into the case. There are at least two openings of the pressure tower insertion opening, the coil insertion opening is provided in a direction substantially perpendicular to the axial direction of the high voltage tower, and the winding axes of the primary coil and the secondary coil are high voltage. The distance between the case inner wall and the surface perpendicular to the plug hole axial direction out of the axially outer peripheral surface of the secondary coil is substantially perpendicular to the axial direction of the tower portion. Ignition coil to play.   The case and the high-voltage tower portion are integrated by fitting, the secondary bobbin is provided with a secondary bobbin terminal for taking out a high voltage directly from the secondary coil, and the high-voltage tower portion is provided with a high voltage from the secondary coil. A high voltage terminal for distributing the voltage to the outside, and a high voltage lead terminal for electrically connecting the high voltage of the secondary coil to the high voltage terminal; The ignition coil according to claim 1, wherein the next bobbin terminal and the high-voltage lead terminal are arranged in a positional relationship that allows connection and fixing at the same time.   The high-pressure tower portion has a high-pressure tower insertion portion slightly larger in diameter than the inner diameter of the high-pressure tower insertion opening portion of the case, and the high-pressure tower insertion portion is inserted toward the high-pressure tower insertion opening portion, 2. The ignition coil for an internal combustion engine according to claim 1, wherein the ignition coil is integrated with the high-pressure tower by fitting.   The high-voltage tower part includes a high-voltage terminal and a high-voltage lead terminal that is electrically connected to the high-voltage terminal, and the high-voltage tower part is arranged inside a plug hole. 1. The ignition coil according to 1.   The axis of the high-voltage tower and the end of the high-voltage lead terminal on the side connected to the secondary bobbin terminal have a certain distance in a direction perpendicular to the axis of the high-voltage tower. The ignition coil according to claim 2.   The ignition coil for an internal combustion engine according to claim 2, wherein the high-voltage lead terminal is made of a plate-like conductive material and has a through hole at one end.   3. The internal combustion engine for an internal combustion engine according to claim 2, wherein the high-voltage lead terminal is a terminal formed of a rod-like conductive material and having a substantially conical spiral portion whose one end portion increases in diameter toward the tip end. Ignition coil.   The high-voltage tower unit includes at least one of a radio noise suppression resistor that suppresses radio noise during coil operation, an inductor having an inductance component, and a misfire prevention diode that prevents misfire. 2. The ignition coil for an internal combustion engine according to claim 1, wherein the ignition coil is disposed.   It has a plug boot made of an elastic material such as rubber attached to the outside of the high-pressure tower portion, and the outer diameter of the high-pressure tower insertion portion is the same as or at least smaller than the outer diameter of the cylindrical portion of the plug boot. The ignition coil for an internal combustion engine according to claim 1, wherein   4. The seal between the high-pressure tower insertion portion of the high-pressure tower portion and the high-pressure tower insertion opening portion of the case is a seal that interposes welding, an adhesive, an O-ring, or the like. The ignition coil for internal combustion engines as described.   The case has a primary bobbin engagement hole that engages with a part of the primary bobbin on a side opposite to the coil insertion opening, and the central core is held inside the primary bobbin, The ignition for an internal combustion engine according to claim 1, wherein a part of the end portion is exposed from the primary bobbin engagement hole, and the outer peripheral core is arranged on the outer periphery of the central core to form a closed magnetic circuit. coil.   2. The ignition coil for an internal combustion engine according to claim 1, wherein the central core is a T-shaped or I-shaped core, and the outer peripheral core is a U-shaped core formed by combining two L-shaped cores.   The ignition coil for an internal combustion engine according to claim 1, wherein the outer peripheral core is covered with a resin or rubber cover on an outer periphery.   The ignition coil for an internal combustion engine according to claim 12, wherein a locking part is provided in a part of the cover, and a key-like part is provided in a part of the case so as to be fitted to the locking part.   2. The ignition coil for an internal combustion engine according to claim 1, wherein the outer peripheral core is formed by laminating silicon steel thin plates of the central core in a direction perpendicular to the laminating direction.   2. The ignition coil for an internal combustion engine according to claim 1, wherein the number of laminated layers of the central core and the outer peripheral core is equal.   An ignition coil for an internal combustion engine, wherein at least two of claims 1 to 16 are combined.

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