JP2013197319A - Resin mold coil device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the gap of a contact part between cores as uniform as possible, when covering the surface with an elastic body by pressing the outermost surface plane part of a core with a molding pin, and to prevent generation of cracks as much as possible when holding a permanent magnet between the cores.SOLUTION: The trace of a molding pin drawn out forms an exposed surface of a core, where the height in the lamination direction of the core is longer than the width in a direction perpendicular to the lamination direction of the core. The temporary fixed trace (molding pin trace) after molding can be reduced, and concentration of stress on a permanent magnet held by the cores is reduced, thus preventing occurrence of cracking in the permanent magnet.

Description

  The present invention is, for example, a coil device used in an ignition coil for an internal combustion engine that supplies a high voltage to cause a spark discharge to an ignition plug of the internal combustion engine, and particularly forms a closed magnetic circuit by combining a plurality of laminated core portions. The present invention relates to a resin mold coil device comprising a so-called mold core in which a core part forming this closed magnetic path is covered with an elastic member, and mounting a coil on a main core part and molding the core part and the coil part with resin. The present invention relates to an ignition coil for an internal combustion engine provided with a mold coil device.

  Such a coil device has a main core portion (also referred to as a main yoke portion or a main core portion) and an auxiliary core portion (also referred to as an auxiliary yoke portion or an auxiliary core portion) that is combined with the main core portion to form a closed magnetic circuit. ) Or a side core portion (also referred to as a side yoke portion or a side core portion).

  Install the coil on the main core (some with an auxiliary core) and assemble the side core (if the main core does not have an auxiliary core, assemble the auxiliary core and side core) Set in. A winding start end portion of the coil is connected to a terminal of an external connection connector provided in the casing. Thereafter, an insulating resin is poured into the casing and molded.

  However, until the resin molding is completed, the divided core members (or permanent magnets including permanent magnets) are affected by molding pressure due to external force and molding resin flow, and molding strain during curing. There is a problem that the position is easily shifted due to the action, and the performance variation of each ignition coil becomes large.

  For example, what is described in Japanese Utility Model Publication No. 59-30501 describes that the periphery of the core portion is previously coated with an elastic body such as a soft resin before resin molding.

  Further, when the core part is covered with an elastic body, the outermost surface flat part of the core part is pressed in the laminating direction with a molding pin so that the cores are not displaced from each other by the flow pressure of the resin.

Japanese Utility Model Publication No.59-30501

  However, the dimensional tolerances of the moldings of each core part are integrated on the contact surfaces of the plurality of laminated core parts, and there are slight gaps that differ for each coil. When covered with an elastic body in the presence of this gap, there is a problem that the coils have different magnetic characteristics for each coil, and the performance of each coil becomes non-uniform.

  In the case where the permanent magnet is provided, there is a possibility that the permanent magnet sandwiched between the cores may be cracked due to temporary fixing when the periphery of the core is covered with the elastic body by the molding pressure of the elastic body.

  The object of the present invention is to provide such a coil device in which the gap of the contact portion between the cores to be combined is as uniform as possible. Further, in the case where the permanent magnet is sandwiched between the yoke portions, the object is to prevent the permanent magnet from being cracked as much as possible when molding with the elastic body.

  In order to achieve the above object, the present invention is to press a laminated surface toward a contact surface of a core with a molding pin when the periphery of the core portion is covered with an elastic body, and to laminate the core A core exposed surface having a shape that is longer in the stacking direction than the width in the direction perpendicular to the direction and parallel to the contact surface is formed.

  The present invention is temporary fixing performed when covering the periphery of the core part, can reduce stress concentration due to the effect of lamination on the permanent magnet sandwiched between the cores, can prevent cracks occurring in the permanent magnet, Moreover, the outflow of the core foreign matter can be suppressed as much as possible by reducing the temporarily fixed trace (molded pin trace) after molding and minimizing the exposure of the core.

1 is a top view showing a first embodiment of an ignition coil for an internal combustion engine according to the present invention. AA sectional view taken on the line AA of FIG. FIG. 3 is a sectional view taken along line BB in FIG. 1. The perspective view which shows the external appearance shape of the core assembly of 1st Example. The perspective view which shows the core mold of 1st Example. VIEW A diagram of FIG. The CC sectional view taken on the line of FIG. The right side enlarged view of FIG. The perspective view which shows the core mold of 2nd Example. VIEW B diagram of FIG.

  Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

  1 to 8 show a first embodiment of an internal combustion engine ignition coil according to the present invention. FIG. 1 is a top view of an internal combustion engine ignition coil according to the present embodiment, and FIG. 2 is a cross-sectional view of the internal combustion engine ignition coil shown in FIG. FIG. 3 is a cross-sectional view of the internal combustion engine ignition coil shown in FIG. 4 is a perspective view showing an arrangement shape of each core, FIG. 5 is a perspective view showing a state in which the core is covered with an elastic body coating, and FIG. 6 is a core mold of the first embodiment as seen from the VIEW A direction of FIG. 7 is a cross-sectional view of the core mold shown in FIG. 6 taken along the line CC, and FIG. 8 is an enlarged view of the right side portion of FIG.

In FIG. 1, the ignition coil 1 includes a coil case 7 made of a resin material.
The coil case 7 is integrally molded with a connector portion 8B for connecting to an external connector and a mounting flange 1B for mounting and fixing the ignition coil 1 on the wall of the engine. The mounting flange 1B is provided with a hole 1C into which a mounting screw is inserted. The surface of the insulating resin 10 for insulating the inside of the coil case is visible on the upper surface of the coil case 7.

As shown in FIGS. 2 and 3, the ignition coil 1 according to the present embodiment has a plug hole insertion portion 9A (described later) formed integrally with the coil case 7 inserted into plug holes formed in each cylinder of the internal combustion engine. The output end of the secondary coil is directly connected to a spark plug (not shown).
This is a so-called independent ignition type ignition coil for an internal combustion engine.

  The ignition coil 1 which becomes 1st Example has the core assembly 6 comprised from the main core part 6a, the side core part 6b, and the auxiliary | assistant core part 6c.

  The core assembly 6 is formed by press-molding a plurality of 0.2 to 0.7 mm silicon steel sheets punched into the shapes of the main core portion 6a, the side core portion 6b, and the auxiliary core portion 6c. A core part is formed.

  As shown in FIGS. 2 and 3, the main core portion 6 a is inserted inside the primary coil bobbin 2 having a rectangular cross section. The primary coil bobbin 2 is formed of a thermoplastic synthetic resin. On the outer periphery of the primary coil bobbin 2, enameled wires having a wire diameter of about 0.3 to 1.0 mm are wound several tens of times per layer, several layers, a total of about 100 to 300 times, and the primary coil 3 is formed. Yes.

  In addition, a secondary coil bobbin 4 having a rectangular cross section is disposed concentrically around the primary coil bobbin 2 with a gap therebetween. The secondary coil bobbin 4 is formed of a thermoplastic synthetic resin in the same manner as the primary coil bobbin 2, and a plurality of winding grooves are formed in the longitudinal direction on the outer periphery of the secondary coil bobbin 4. On the outer periphery of the secondary coil bobbin 4, enameled wires having a wire diameter of about 0.03 to 0.1 mm are wound about tens to hundreds of layers in each groove for a total of about 5,000 to 30,000 times. A coil 5 is formed.

  The primary coil bobbin 2 is inserted into the secondary coil bobbin 4. Moreover, between the auxiliary core part side end of the main core part 6a and the auxiliary core part 6c, it magnetized in the reverse direction with respect to the direction of the magnetic flux generated in the main core part 6a when the primary coil 3 is energized. A magnet member 11 is mounted in a sandwich shape. The primary coil bobbin 2 and the primary coil part C1 composed of the primary coil 3 wound around the primary coil bobbin 2, the secondary coil bobbin 4 and the secondary coil part C2 composed of the secondary coil 5 wound around the secondary coil bobbin 4 and the core The assembly 6 is housed in a coil case 7.

  The coil case 7 is integrally molded with a connector portion 8B. The connector portion 8B has an electrical connection terminal 8A for electrically connecting the primary coil 3 to the outside integrally with the resin molded body of the coil case 7. It is insert molded. A protruding portion 2C extending to the upper surface in the stacking direction of the auxiliary core portion 6c is formed at the end of the primary coil bobbin 2 of the primary coil 3 on the auxiliary core portion 6c side, and the input terminal 8C is press-fitted into the protruding portion 2C. . The input terminal 8C and the electrical connection terminal 8A of the connector portion 8B are electrically connected by the wiring 8D inside the coil case 7, and the current supplied to the primary coil 3 is supplied via the electrical connection terminal 8A. . Although not shown, an external connector is inserted and connected to the connector portion 8B, and the electrical connection terminal 8A is connected to the power supply terminal of the external connector.

  On the other hand, the high voltage terminal 9 is integrally formed by resin molding on the plug hole insertion portion 9A side of the coil case 7. The high voltage terminal 9 is connected to the output terminal 5A of the secondary coil 5. A high voltage is induced in the secondary coil 5 by interrupting the current supplied to the primary coil 3 by a semiconductor switching element (not shown). The high voltage induced in the secondary coil 5 is supplied to a spark plug (not shown) through a high voltage terminal 9 integrally molded with the coil case 7, and the spark plug generates a spark discharge.

  In the state where the output end 5A of the winding of the secondary coil 5 is connected to the high voltage terminal 9 and the input end 8C of the winding of the primary coil 3 is connected to the electrical connection terminal 8A of the connector portion 8B, the core assembly 6, The coil part C1 and the secondary coil part C2 are accommodated in the coil case 7 and set. The coil case 7 is filled with a thermosetting resin (specifically, an epoxy resin) as the insulating resin 10. The insulating resin 10 is filled in the entire inside of the coil case 7, and the primary coil 3 wound around the primary coil bobbin 2, the gap between the windings of the secondary coil 5 wound around the secondary coil bobbin 4, the primary coil portion C1. , The secondary coil part C2, the periphery of the core assembly 6 and the gap between them, the connection part between the input end 8C of the primary coil 3 and the connection terminal 8A of the connector part 8B, the high-voltage terminal 9 and the secondary coil 5 These are filled around the connection portion of the output end 5 </ b> A to insulate them and to be integrated with the coil case 7.

  As shown in FIGS. 4 and 5, the core assembly 6 to which the present invention relates includes three parts divided into a main core part 6 a, a side core part 6 b, and an auxiliary core part 6 c. The magnet member 11 has a thin plate shape and is assembled between the main core portion 6a and the auxiliary core portion 6c. Further, as shown in FIG. 4 and FIG. 5, the joining surface portions 6a1 and 6b2 between the main core portion 6a and the side core portion 6b, the joining surface 6c2 between the magnet member 11 and the auxiliary core portion 6c, and the side core portion 6b and the auxiliary core portion 6c. Except for the joining surfaces 6c1 and 6b1 and the joining surface 6a2 between the magnet member 11 and the main core portion 6a, the outer surfaces of the core assembly 6 and the magnet member 11 are covered with a molding material. Hereinafter, this coating layer is referred to as core molds 12a and 12b. The core molds 12a and 12b are made of thermoplastic resin, elastomer or rubber.

  In the embodiment, a non-magnetized magnet member 11 is sandwiched between the flange 6a2 formed at the end of the main core portion 6a and the auxiliary core portion 6c and set in a mold, and the mold is placed in the mold. A material (thermoplastic resin, elastomer or rubber such as silicon rubber) is injected, and the peripheral surfaces of the main core portion 6a, the magnet member 11 and the auxiliary core portion 6c are covered with a molding material, and these three members are formed into one mold assembly. Configured as parts.

  At this time, molding is performed by pressing the three members tightly so that the molding material does not flow into the joint surface between the main core and the magnet member 11 and the joint surface between the magnet member 11 and the auxiliary core portion 6c. This pressing is referred to as temporary fixing, and the temporary fixing uses a pin called a molding pin, and the molding pin is pressed against the auxiliary core portion 6c to prevent the molding material from flowing into the joint surface of the three members. Further, the molding material is closely attached to the surface of the mold so that the molding material does not enter the joint surface (both sides) 6c1 of the auxiliary core portion 6c with the side core portion 6b and the contact surface 6a1 of the main core portion 6a with the side core portion 6b. did. A tape that can be removed later is affixed to the joint surface (both sides) 6c1 between the auxiliary core portion 6c and the side core portion 6b or the contact surface 6a1 with the side core portion 6b of the main core portion 6a, and then molded, and then the tape is peeled off. The joint surface may be exposed.

  If comprised in this way, since the position at the time of the assembly of the auxiliary | assistant core part 6c, the magnet member 11, and the main core part 6a will be decided in a shaping | molding die, these will not raise | generate a position shift after mold shaping | molding. Further, the peripheral surface of the magnet member 11 sandwiched between the main core portion 6a and the auxiliary core portion 6c is covered with a coating of the core mold 12a for protection. For this reason, since the edge part of the magnet member 11 is hard to be damaged with respect to the impact at the time of assembly, etc., even if it is damaged, the pieces of the permanent magnet are not scattered. Do not let it fall.

Next, the main part of the present invention will be described with reference to FIGS.
As shown in FIGS. 6 and 8, the core mold 12a and the core mold 12b are coated on the peripheral surfaces of the main core portion 6a, the auxiliary core portion 6c, the side core portion 6b, and the magnet member 11 while being temporarily fixed in the mold. As a result, core exposed surfaces 6b3 and 6c3 are formed.

  At this time, the shape of the core exposed surface 6c3 is set such that the width W2 in the stacking direction is longer than the width W1 in the direction perpendicular to the stacking direction of the auxiliary core portion 6c and parallel to the exposed surface. By doing so, it is possible to suppress stress concentration due to the effect of stacking on the magnet member 11 sandwiched between the main core portion 6a and the auxiliary core portion 6c, leading to prevention of breakage of the magnet member.

  The core exposed surfaces 6c3 and 6b3 at this time are arranged so as to be symmetric with respect to the center line Y shown in FIG. This is to apply a force evenly to the left and right when temporarily fixing.

  In forming the core exposed surface 6c3, since the magnet member 11 is sandwiched between the main core portion 6a and the auxiliary core portion 6c, the range in which the core exposed surface 6c3 is formed is included within the range of the magnet member 11. To. Specifically, as shown in FIGS. 6 and 7, when the lateral width of the magnet member 11 is L, the magnet member 11 is formed 0.15 L or more inside from the left end and the right end of the magnet member 11. This is because when the core exposed surface 6c3 is formed on the outer side, stress tends to concentrate on the edge portion of the magnet member 11, and the magnet member 11 is easily damaged.

  For the same reason, assuming that the width in the direction perpendicular to the lateral width L of the magnet member 11 is H, the core exposed surface 6c3 is formed in a range inside 0.15H from the upper end and the lower end of the magnet member 11.

  Further, as shown in FIG. 7, the core molds 12a1 and 12b1 around the core exposed surfaces 6c3 and 6b3 are rounded. This is to make the core exposed surface as small as possible and prevent the core foreign matter from flowing out. Furthermore, by taking R, the mold life of the forming pin can be extended.

  Next, a second embodiment will be described with reference to FIGS. The second embodiment shows an example in which the shape of the core exposed surfaces 6b3 and 6c3 of the first embodiment is changed.

  9 and 10 show an example in which two exposed core surfaces 6b4 and 6c4 are formed in the core stacking direction. By forming the core exposed surface in this way, the same effect as in the first embodiment can be obtained.

  At this time, in the second embodiment, the two exposed core surfaces 6b4 and 6c4 are formed in the core stacking direction, but a large number of exposed core surfaces 6b4 and 6c4 may be formed.

  The embodiments of the present embodiment are summarized as follows.

Embodiment 1
To accommodate a primary coil wound around a primary bobbin, a secondary coil wound around a secondary bobbin, a core laminated with steel plates for magnetically coupling the primary coil and the secondary coil, and these In the ignition coil for an internal combustion engine, which is made of an insulating resin for electrically insulating each member and in which a coating layer is formed of an elastic body around the iron core, when the coating layer is formed, The core exposed surface formed by the molding pin used for temporary fixing (fixed by pressing the molding pin against the iron core) to prevent displacement in the direction perpendicular to the laminating direction due to the resin flow pressure of the iron core. An ignition coil for an internal combustion engine, characterized in that a width W2 of the iron core in the stacking direction of the iron core exposed surface is longer than a width W1 in a direction perpendicular to the stacking direction of the core and parallel to the contact surface.

Embodiment 2
In the internal combustion engine ignition coil according to Embodiment 1, two or many of the molding pins are used for the temporary fixing, and the direction perpendicular to the molding pin with respect to the contact surface of the iron core that contacts the molding pin An ignition coil for an internal combustion engine, characterized in that the exposed surface of the iron core is formed so as to be symmetric with respect to the center line of the contact surface of the iron core.

Embodiment 3
2. The ignition coil for an internal combustion engine according to the first embodiment, wherein two or a plurality of exposed surfaces of the iron core are arranged in the stacking direction of the iron cores.

Embodiment 4
In the ignition coil for an internal combustion engine according to any one of the first to third embodiments, a permanent magnet (whether magnetized or not magnetized) is sandwiched between any of the main iron core portion, the auxiliary iron core portion, and the side iron core portion. An ignition coil for an internal combustion engine.

Embodiment 5
In the ignition coil for an internal combustion engine according to the fourth embodiment, two or a plurality of the exposed surfaces of the iron core are set to the width H in the stacking direction of the iron cores of the permanent magnet sandwiched between the iron cores. An ignition coil for an internal combustion engine, which is not formed within a range of 0.15H from the upper end and the lower end of the width H of the permanent magnet.

Embodiment 6
6. The ignition coil for an internal combustion engine according to the fourth embodiment, wherein two or many of the exposed core surfaces are perpendicular to the stacking direction of the iron cores of the permanent magnet sandwiched between the iron cores. An internal combustion engine ignition coil characterized by not being formed in a range of 0.15 L from the right end and the left end of the width L of the permanent magnet with respect to a width L in a direction parallel to the surface.

DESCRIPTION OF SYMBOLS 1 Ignition coil 2 Primary coil bobbin 3 Primary coil 4 Secondary coil bobbin 5 Secondary coil 6a Main core part 6b Side core part 6c Auxiliary core part 7 Coil case 10 Insulating resin 11 Magnet members 12a and 12b Core mold

Claims (6)

To accommodate a primary coil wound around a primary bobbin, a secondary coil wound around a secondary bobbin, a core laminated with steel plates for magnetically coupling the primary coil and the secondary coil, and these In the ignition coil for an internal combustion engine, which is made of an insulating resin for electrically insulating each member, and in which a coating layer is formed with an elastic body around the core,
An ignition coil for an internal combustion engine, wherein an exposed surface of the core formed on the covering layer has a shape in which a width W1 of an exposed surface in a direction perpendicular to the width W2 in the stacking direction of the cores is shorter.   2. The ignition coil for an internal combustion engine according to claim 1, wherein two or more ignition coils are provided, and the core exposed surface is formed so as to be symmetrical with respect to a center line of the laminated surface of the core. An ignition coil for an internal combustion engine.   2. The ignition coil for an internal combustion engine according to claim 1, wherein a plurality of the core exposed surfaces are arranged in a stacking direction of the cores. 3.   4. The ignition coil for an internal combustion engine according to claim 1, wherein the core is composed of a main core portion, an auxiliary core portion, and a side core portion, and a permanent magnet is sandwiched between any of them. An ignition coil for an internal combustion engine.   5. The ignition coil for an internal combustion engine according to claim 4, wherein a width of the permanent magnet is greater than a width H in a stacking direction of the core of the permanent magnet sandwiched between the cores. An ignition coil for an internal combustion engine, wherein the ignition coil is formed inside 0.15H from an upper end and a lower end of H.   5. The ignition coil for an internal combustion engine according to claim 4, wherein the exposed surfaces of the plurality of cores have a width L in a direction perpendicular to a stacking direction of the cores of the permanent magnet sandwiched between the cores. An ignition coil for an internal combustion engine, wherein the ignition coil is formed inside a range of 0.15 L from the right end and the left end of the width L of the permanent magnet.