JP2012064610A - Closed magnetic circuit voltage transformer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve such a problem that since a closed magnetic circuit is assembled by mating a core formed of multiple parts in a closed magnetic circuit voltage transformer, a clearance occurs at the mating part when the core is mated due to manufacturing tolerance of a component or dimensional variation when the closed magnetic circuit is assembled and performance variation (machine difference) occurs among individual closed magnetic circuit voltage transformers.SOLUTION: The problem is solved by providing the mating part with two mating plane areas adjacent to each other, and a step in the axial direction formed between the two mating plane areas. Preferably, a magnet is provided in a cavity which is provided between one end of a center core and a side core.

Description

  The present invention relates to a closed magnetic circuit type transformer used for an ignition coil that supplies a high voltage to an ignition plug, for example, to generate a spark discharge in an ignition plug of an internal combustion engine.

  An example of a conventional closed magnetic circuit type transformer is an ignition coil for an internal combustion engine as shown in FIG. 6 (Japanese Patent Laid-Open No. 2005-19869). In this example, a center iron core and a side iron core surrounding the center iron core are provided so as to form a closed magnetic circuit. A primary coil connected to the battery is wound around the outer periphery of the center core, and a secondary coil connected to the plug is wound around the outer periphery of the primary coil to form a closed magnetic circuit type transformer. is doing. The iron core and the coil are accommodated in a coil case, and a portion not filled with an insulating resin is insulated in the coil case. In addition, a gap is provided between one end of the center iron core and the side iron core, and some of the gap portions include a permanent magnet.

Japanese Patent Laid-Open No. 2005-19869

  In such a closed magnetic circuit type transformer, since a closed magnetic circuit is assembled by fitting an iron core formed from a plurality of parts, due to manufacturing tolerances of parts and dimensional variations at the time of assembly, there is a gap in the fitting part at the time of fitting. May occur. For this reason, in such a closed magnetic circuit type transformer, performance variation (machine difference) occurs depending on the individual closed magnetic circuit type transformer. Also, in the type in which permanent magnets are arranged in a closed magnetic path, in the case of being magnetized after being fitted in a non-magnetized state, there is no force to hold the member that becomes the magnet between the iron core, the iron core and the magnet The member cannot be fixed.

  An object of the present invention is to allow the iron core to be fixed even when the permanent magnet is not magnetized when there is little performance variation (machine difference) and a permanent magnet is provided.

  The above object can be achieved by providing the fitting portion with two adjacent fitting plane areas and an axial step formed between the two fitting plane areas. Preferably, a magnet is provided in a gap provided between one end of the center iron core and the side iron core.

  According to the present invention, the machine difference of a closed magnetic circuit type transformer such as an ignition coil can be reduced, and the yield is improved. In the case of a type using a permanent magnet, the magnet can be easily fixed between the iron cores even in a non-magnetized state.

The top view of one Example of the internal combustion engine ignition coil provided with the closed magnetic circuit type transformation apparatus by which this invention was implemented. AA sectional drawing of FIG. BB sectional drawing of FIG. Sectional drawing which expanded only the iron core part of FIG. The fitting part enlarged view of the iron core of FIG. Sectional drawing which shows the conventional iron core shape for comparing with FIG. (A), (B) The figure which shows the other Example of the internal combustion engine ignition coil as a closed magnetic circuit type transformation apparatus (with magnet) by which this invention was implemented. (A), (B), (C) The figure which shows the other Example of the internal combustion engine ignition coil as a closed magnetic circuit type transformation apparatus (no magnet) in which this invention was implemented.

  Hereinafter, an internal combustion engine ignition coil as a closed magnetic circuit type transformer (with a magnet) in which the present invention is implemented will be described with reference to the drawings.

  A first embodiment of the present invention will be described in detail with reference to FIGS.

  The internal combustion engine ignition coil 1 is an independent ignition type internal combustion engine ignition coil that is attached to a plug hole of each cylinder of the internal combustion engine and directly connected to the ignition plug.

  The internal combustion engine ignition coil 1 has a closed magnetic circuit type iron core 6. This closed magnetic path type iron core 6 is formed by laminating a plurality of press-molded 0.2 to 0.7 mm silicon steel plates.

  The iron core 6 includes a center iron core portion 6A (hereinafter referred to as a main iron core 6A) around which an ignition coil is wound. The iron core 6 is further surrounded by side iron cores 6C and 6B.

  The side iron core 6C is located at one end of the main iron core 6 at a right angle with respect to the main iron core 6A. The side iron core central portion 6CC is located at both ends of the side iron core central portion 6CC, and is paired in parallel with the main iron core 6A. The side iron core legs 6CR and 6CL are provided, and thus the side iron core 6C has a C-shaped cross section. The inner peripheral surface of the side iron core center portion 6CC is in close contact with one end of the main iron core 6A to form a magnetic path. On the other end of the main iron core 6A, an enlarged flat portion 6AF extending on both sides is formed integrally with the main iron core 6A. The auxiliary iron core 6B as a part of the side iron core having the inner surface facing the enlarged flat surface portion 6AF is fitted at both ends with the ends of the pair of side iron core legs 6CR and 6CL, and as a result, a part of the closed magnetic circuit is formed. Form.

  A member that becomes the permanent magnet 11 or the permanent magnet itself is sandwiched between the enlarged flat surface portion 6AF at the other end of the main iron core 6A and the inner surface of the auxiliary iron core 6B.

  As shown in FIGS. 2 and 3, a primary bobbin 2 and a secondary bobbin 4 are concentrically mounted in that order around the main iron core 6A.

  The primary bobbin 2 is made of a thermoplastic synthetic resin. The primary bobbin 2 is formed with a primary coil 3 in which enameled wires having a wire diameter of about 0.3 to 1.0 mm are stacked and wound on the primary bobbin 2 several tens of times per layer for a total of several hundred to three hundred times. ing.

  A secondary bobbin 4 is disposed on the outer periphery of the primary bobbin 2 with a gap. The secondary bobbin 4 is formed of a thermoplastic synthetic resin in the same manner as the primary bobbin 2, and a plurality of winding grooves are formed on the secondary bobbin 4. A secondary coil 5 is formed on the secondary bobbin 4 by being divided and wound into a total of about 5,000 to 30,000 times using an enameled wire having a wire diameter of about 0.03 to 0.1 mm. As described above, the primary bobbin 2 is inserted inside the secondary bobbin 4. A permanent magnet magnetized in the direction opposite to the magnetic flux passing through the iron core 6 by energization of the primary coil is inserted into the gap between the other end of the center iron core portion 6A and the side iron core portion 6B. The iron coil 6, the primary coil 3 wound around the primary bobbin 2, and the secondary coil 5 wound around the secondary bobbin 4 are housed in a coil case 7.

  The primary coil 3 is connected to an external power source (battery) via a terminal 8 of a connector portion formed in the case 7. On the other hand, the secondary coil 5 is connected to the high voltage terminal 9 (provided on the high voltage side of the coil case 7) connected to the spark plug inside the coil case 7. Thus, a high voltage for generating a spark discharge in the spark plug is induced in the secondary coil 5 by energization / cutoff of the primary coil 3. The high voltage induced in the secondary coil 5 is supplied to the spark plug via the high-voltage terminal 9, and the spark plug generates a spark discharge upon receiving the high voltage induced in the secondary coil 5.

  The coil case 7 encloses an insulating resin (specifically, an epoxy resin) 10 that is a thermosetting resin. This insulating resin (specifically, epoxy resin) 10 is wound around the iron core 6 accommodated in the coil case 7, around the primary coil 3 wound around the primary bobbin 2, and the secondary bobbin 4. The secondary coil 5 and the gap between them are filled. When the insulating resin 10 is cured, the primary coil 3, the secondary coil 5, the primary bobbin 2, the secondary bobbin 4 and the iron core 6 housed in the coil case are insulated and integrated. It is fixed with.

  As shown in FIG. 4, the iron core 6 of the present embodiment has a pair of side iron core legs 6CR, 6CL (first side iron core of claim) in addition to the main iron core 6A and auxiliary iron core 6B (second side iron core of claim). ) And a side iron core central portion 6CC (the third iron core in the claims) that connects them to each other.

  FIG. 6 shows an enlarged view of a fitting portion between the auxiliary iron core 6B and the side iron core 6C. A fitting portion between one end 6BL of the auxiliary iron core 6B and one end portion of the side iron core leg portion 6CR has a stepped shape as shown in FIG. 6, and is formed at the back of the stepped portion 62 (round frame P3 portion). In the first fitting plane area 61 (round frame P2 portion), the inner surface of the tip 6CP of the side iron core leg 6CR and the outer surface of the tip 6B1 of the auxiliary iron core 6B face each other with a clearance of 0.1 mm or less or in a surface contact state. is doing. A second fitting plane area 63 is formed on the outside of the stepped portion 62. In this area, the inner surface of the tip 6C1 of the side iron core leg 6CR and the outer surface of the one end 6BP of the auxiliary iron core 6B are in pressure contact state. Are facing each other. In the first mating plane area 61, if the contact state is 0.1 mm or less and the width is more than 0.5 times that of the auxiliary iron core 6B, the output energy reduction of the ignition coil is 1% or less. The decrease in output energy is a level that does not affect the output energy.

  The first fitting plane area 61 and the second fitting plane area 63 are configured such that the distances L1 and L2 from the center of the main iron core 6A are L1 <L2.

  For this reason, when the auxiliary iron core 6B is fitted to the side iron core 6C, the tip 6B1 of the auxiliary iron core 6B is pushed into the stepped portion 62 while pushing the side iron core leg portion 6C1 outward, and points to the stepped portion 62. When this occurs, the return force of the elastic force of the side iron core leg 6C1 narrows to the outer surface of the end 6BR of the auxiliary iron core 6B that forms the second fitting plane area 63 along the inclined surface (taper) of the stepped portion 62, The inner surface of the side iron core leg portion 6C1 is in pressure contact with the outer surface of the end portion 6BR of the auxiliary iron core 6B to form the second fitting plane area 63.

  At this time, the pressure input (pressure contact force) acts in a direction substantially perpendicular to the direction in which the auxiliary iron core 6B is inserted into the side iron core legs 6CL (6CR). In the two mating plane areas, the outer surface of the end portion 6BR of the auxiliary iron core 6B and the inner surface of the side iron core leg portion 6CL face each other.

  Insertion of the front end portion 6B1 of the auxiliary iron core 6B is restricted by a restriction portion 6C2 formed at the innermost peripheral portion of the side iron core leg portion 6CL. This prevents excessive insertion. Further, after the auxiliary iron core 6B is inserted into the side iron core leg portion 6CL (6CR) and fitted, if a force in the pulling direction acts on both, the stepped portion 62 formed between the pair of fitting plane areas 61 and 63 is formed. Acts as a stopper for the tip 6B1 of the auxiliary iron core 6B.

  By this fitting step, the main iron core 6A and the magnet member (or permanent magnet) 11 are sandwiched between the side iron core center portion 6CC and the auxiliary iron core 6B. Thus, even when the main iron core 6A and the magnet member (or permanent magnet) 11 are sandwiched in the insertion direction, the degree of freedom of movement can be made only in the dimension variation. A void that is so large as to cause an output energy loss is not formed. Moreover, the main iron core 6A and the magnet member (or magnet) are placed between the side iron core central portion 6CC and the auxiliary iron core 6B by forming the stepped portion 62 between the two fitting plane areas 61 and 63 into a tapered shape. Since it is held in a state having elasticity, an excessive force is not applied to the magnet member 11. In Example 1, the material of the iron core 6 is composed of a laminated body of silicon steel plates, but the same shape can be applied to the fitting structure even by compression molding of iron-based powder.

  The problems and embodiments of the examples are summarized as follows.

  In this embodiment, the present invention is applied to an ignition coil for an independent ignition type internal combustion engine that is attached to a plug hole of each cylinder of the internal combustion engine and directly connected to the ignition plug.

  Specifically, the side iron core and the center iron core constitute a magnetic circuit, and the center iron core is arranged with one end fixed to the side iron core and the other end provided with the side iron core and the gap, and a closed magnetic circuit. A permanent magnet is provided in the gap, and a primary coil is wound on the primary bobbin in which the center iron core is accommodated, and the secondary bobbin arranged with the primary bobbin and the gap is accommodated. A secondary coil is wound and housed on the top, and the primary bobbin and the secondary bobbin are disposed at intervals with each other and housed in the coil case, and an insulating resin is enclosed in the coil case and integrated.

  In such an ignition coil for an internal combustion engine, if the iron core is divided into three parts and a permanent magnet is provided in the gap, a gap or the like may be generated in the fitting part during fitting due to a variation in dimensions. Becomes larger. In addition, when the permanent magnets are fitted in a non-magnetized state, there is no force to push even if they are inserted, and the iron cores cannot be fixed.

  In the present embodiment, the fitting portion between the both end portions 6BR and 6BL of the auxiliary iron core 6B (second side iron core) and the side iron core leg portions 6BR and 6BL is inserted in the insertion direction along the longitudinal direction of the main iron core 6A. The pressure input (pressure contact force) at this time is approximately perpendicular to the longitudinal direction of the main iron core 6A and is at both ends 6BR of the auxiliary iron core 6B (second side iron core) with respect to the central axis in the longitudinal direction of the main iron core 6A. 6BL and the side iron core leg portions 6BR and 6BL have a shape that works so that the pressing force acting between them faces each other.

  The embodiment is as follows.

Embodiment 1
The fitting portions P1, P2, and P3 of the both end portions 6BR and 6BL of the auxiliary iron core 6B and the side iron core leg portions 6CR and 6CL have a stepped shape, and a pair of fitting plane areas 61 and 63 are provided across the stepped portion 62. In the fitting plane area 61, a press-fit contact portion or a gap of 0.1 mm or less is provided.

Embodiment 2
In the ignition coil described in the first embodiment, a press-fit contact portion or a gap of 0.1 mm or less in the fitting plane area 61 of the fitting portions of the both end portions 6BR and 6BL of the auxiliary iron core 6B and the side iron core leg portions 6CR and 6CL. The area of is set to 0.5 times or more of the cross-sectional area of the auxiliary iron core 6B.

Embodiment 3
In the ignition coil described in the second embodiment, from the central axis LL of the main core 6A of the two fitting plane areas 61, 63 of the two ends 6BR, 6BL of the auxiliary iron core 6B and the side iron core legs 6CR, 6CL. The dimensions L1 and L2 are configured so that the dimension L2 of the fitting plane area 63 formed at the back of the stepped shape is widened, and the stepped portion 62 connecting the steps is tapered.

Embodiment 4
In the ignition coil described in the third embodiment, the side iron core leg portions 6CR, the restricting portions 6C2 for restricting excessive insertion with respect to the inserting direction of the front end portion 6B1 of the auxiliary iron core 6B are provided in the back of the fitting plane area 63. A stopper was provided on the inner peripheral surface side of 6CL.

Embodiment 5
In the ignition coils described in Embodiments 1 to 4, the iron core 6 is formed by laminating silicon steel plates, or by an iron-based powdered material.

  The present invention is not limited to the ignition coil for an internal combustion engine of an independent ignition type but can be used for a closed magnetic circuit type ignition coil, a transformer, and the like.

  If the iron core has a different shape, it should be used for the CE type, CT type, CI type, EI type, etc. described in JP-A-3-116704 and US Pat. No. 4,990,881. Can do.

  FIGS. 7 and 8 show diagrams used for the CE type, the CT type, the CI type, and the EI type.

  7 and 8, S is a round frame indicating the entire stepped portion. LL is the longitudinal center axis of the main iron core 6A, CP1 and CP2 are fitting plane areas 61 and 63 of the first embodiment, SP is the stepped portion 62 of the first embodiment, and ST is the regulation of the first embodiment. Each part 6C2 is shown. Other reference numerals are the same as those in the first embodiment, and indicate the same items.

  In FIG. 7A, the main iron core 6A is formed integrally with the side iron core 6C, and the two fitting portions of the both end portions 6BR and 6BL of the auxiliary iron core 6B and the side iron core leg portions 6CR and 6CL are solid circles S. As shown by the dotted round frame S, an example formed at different positions is shown. What was formed in the position of a broken line becomes an E-I type iron core with a magnet. What is formed at the position of the solid line is a C-T iron core with magnet. The fitting portion may be formed at any position of the side core leg portions 6CR and 6CL.

  Further, in the fitting portion, either end portion 6BR, 6BL of the auxiliary iron core 6B and the front end portion of the side iron core leg portions 6CR, 6CL may be located outside.

  In FIG. 7B, the main iron core 6A is divided into two at the center, and each is provided integrally with the auxiliary iron core 6B and the side iron core 6C, and the type in which the magnet is arranged at the axial center position of the main iron core 6A is shown. Show. In this case, it becomes an EE type iron core with a magnet.

  FIG. 8 (A) shows the type without magnet of FIG. 7 (A). A broken line indicates a magnetless CT core and a solid line indicates a magnetless IE or magnetless CT core. In the thing of a broken line, the side iron core leg part 6CR, 6CL side shows the type arrange | positioned on the outer side of a fitting part.

  FIG. 8B shows a structure in which fitting portions are provided between both ends 6AR, 6AL of the main iron core 6A and both ends 6BR, 6BL of the auxiliary iron core 6B. In this example, it becomes a C-I type iron core without a magnet. In this embodiment, both end portions 6BR and 6BL of the auxiliary iron core 6B are outside the fitting portion.

  FIG. 8 (C) shows that both end portions 6AR and 6AL of the main iron core 6A are outside the fitting portion in FIG. 8 (B).

  In the first embodiment described above, and in the embodiments shown in FIGS. 7A, 7B and 8A, the plane forming the fitting plane area is formed in a plane parallel to the central axis of the main iron core 6A. Is done. In the embodiment of FIGS. 8B and 8C, it is formed by a plane perpendicular to the central axis of the main iron core 6A.

DESCRIPTION OF SYMBOLS 1 Ignition coil for internal combustion engines 2 Primary bobbin 3 Primary coil 4 Secondary bobbin 5 Secondary coil 6 Iron core 7 Coil case 8 Terminal 9 High voltage terminal 10 Insulating resin 11 Permanent magnet

Claims (9)

A main iron core fitted with a coil,
A side iron core that forms a closed magnetic circuit in combination with this main iron core,
In what has a fitting part of an iron core in the middle of the closed magnetic path,
The fitting portion is a closed magnetic circuit type transformer having two adjacent fitting plane sections and an axial step formed between the two fitting plane sections. In claim 1,
A closed magnetic circuit type transformer in which a permanent magnet is disposed in the middle of the closed magnetic circuit. In one of claims 1 and 2,
The main magnetic core and the side iron core are closed magnetic circuit type transformers configured such that pressure input acts in a direction intersecting the insertion direction when both iron cores are inserted in the fitting portion. In claim 3,
The said side iron core is a closed magnetic circuit type | mold transformer provided with the 1st side iron core part parallel to the said main iron core, and the 2nd side iron core provided in the end of the said main iron core, and connecting the said 1st side iron core and the said main iron core. The thing of Claim 4 WHEREIN:
The first side iron core is formed integrally with two iron core portions parallel to the center iron core and the third iron core portion connecting the two iron core portions with the center iron core sandwiched between them.
A closed magnetic circuit type transformer configured to constitute a pair of closed magnetic circuits passing through the main iron core by assembling the second side iron core portion in parallel with the third iron core portion. The thing of Claim 5 WHEREIN:
The fitting portion has two fitting portions of the first side iron core and the second side iron core with respect to a central axis in the longitudinal direction of the center iron core, and the two fitting portions are arranged symmetrically. Closed magnetic circuit type transformer. The thing of Claim 6 WHEREIN:
Each of the two fitting portions includes the two fitting plane areas facing each other with respect to the central axis in the longitudinal direction of the center iron core, and the stepped portion formed between the two fitting plane areas. Road type transformer. In claim 1,
The fitting part is a closed magnetic circuit type transformer having a stopper for receiving the tip of at least one iron core. In the thing of Claim 1 thru | or 7,
The planes of the two mating plane areas are formed in a direction along the central axis of the main iron core, and the plane of the mating plane area on the outer side located on the outer side is more main than the plane of the mating plane area on the other side. A closed magnetic circuit type transformer formed at a position close to the central axis of the iron core.

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