JP2006140260A - Ignition coil for internal combustion engine, and automobile - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an improved ignition coil for an internal combustion engine in which parts are surely positioned and an insulating material runs through gaps between the parts. <P>SOLUTION: The ignition coil for the internal combustion engine comprises a secondary coil 4 in which a central core 5 is inserted, a primary coil 3 in which the secondary coil is inserted, and a power feeder 7 arranged at the upper part of the primary coil 3. A hooking projection 37 is formed at the lower part of the power feeder 7 that contacts with the primary coil 3, and a cylindrical hole 26 for receiving a part of the hooking projection 37 is formed at the upper part of the primary coil 3. Engagement between the hooking projection 37 and the cylindrical hole 26 forms a gap between the power feeder 7 and the primary coil 3 for the accurate positioning of them. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an ignition coil for an internal combustion engine that is attached to a plug hole of an engine of an automobile or the like and is used with an ignition plug attached to a tip portion thereof, and an automobile incorporating the ignition coil.

The ignition coil is generally composed of a secondary coil part in which a central iron core is inserted, a primary coil part arranged outside the secondary coil part, and an outer iron core arranged outside the primary coil part. . And the primary coil part by which the exterior iron core was externally fitted is accommodated in a coil case in the state which included the secondary coil part and has arrange | positioned the electric power feeding part to the upper part (patent document 1). The power supply unit is a part that supplies a pulse current to the primary coil unit.
JP 2004-71911 A

  In the ignition coil having such a configuration, with the primary coil portion, the secondary coil portion, and the center core portion 5 positioned concentrically, an insulating material such as a thermosetting epoxy resin is vacuum-injected so as to eliminate gaps in the respective portions. The Thereafter, the insulating material is thermally cured, and the above-described parts are fixed in a state where an appropriate gap is maintained.

  However, in the conventional ignition coil, since the power feeding part is disposed in contact with the primary coil part, there is a problem that the flow of the insulating material is obstructed at the bottom surface of the power feeding part when the insulating material is filled. Therefore, although it is said that vacuum injection is performed, there is a possibility that the insulating material may not be spread completely. In such a case, there arises a disadvantage that a predetermined insulating property cannot be ensured.

  The present invention has been made in view of such problems, and an object of the present invention is to provide an internal combustion engine ignition coil that can position each part with certainty and is improved so that an insulating material can be spread over a gap between the parts. It is another object of the present invention to provide an automobile incorporating the ignition coil thus improved.

  In order to achieve the above object, the present invention includes a secondary coil part in which the central core is inserted, a primary coil part in which the secondary coil part is inserted, and a power feeding part that is disposed on the upper part of the primary coil part. In the internal combustion engine ignition coil provided, by providing an engagement protrusion protruding in the axial direction on at least one of the lower part of the power supply part that contacts the primary coil part or the upper part of the primary coil part that contacts the power supply part, A gap is formed between the power feeding portion and the primary coil portion, and the positional relationship between the power feeding portion and the primary coil portion is fixed by the engagement protrusion.

  It is preferable that three or more engagement protrusions are provided. In this case, the stability during assembly is increased. Corresponding to the fact that the engaging protrusion is provided on one side of the primary coil part and the power feeding part, a part of the engaging protrusion is provided on the other side of the primary coil part and the power feeding part. If the receiving part which receives is formed, positioning will be easy. Further, the present invention is an automobile incorporating any of the ignition coils described above.

  According to the above-described present invention, it is possible to realize an internal combustion engine ignition coil that can reliably position each part and that is improved so that an insulating material is distributed in the gaps between the parts.

  Hereinafter, based on an Example, embodiment of this invention is described more concretely. Fig.1 (a) is a fragmentary sectional view which shows schematic structure of the ignition coil CL based on an Example, FIG.1 (b) is a whole circuit block diagram of the ignition coil CL.

  The ignition coil CL includes a coil case 1 (1a, 1b, 1c) formed integrally with a plastic mold, a rubber plug cap 2 fitted to the lower end portion of the coil case 1, and an internal coil case 1. The primary coil portion 3 to be inserted, the secondary coil portion 4 to be inserted into the primary coil portion 3, the center core portion 5 to be inserted into the secondary coil portion 4, and the outer periphery of the primary coil portion 3 are elastically fitted. It is comprised centering on the exterior iron core 6 and the electric power feeding part 7 accommodated in the upper part of the coil case 1. FIG.

  The primary coil portion 3, the secondary coil portion 4, and the center core portion 5 are positioned concentrically, and a thermosetting epoxy resin 8 is vacuum-injected and cured so as to eliminate gaps in the respective portions. The power supply unit 7 is a part that supplies a pulse voltage to the primary coil unit 3. In this embodiment, the power supply unit 7 includes a power transistor PTr that performs an ON / OFF operation in response to the ignition pulse S (FIG. 1B). reference).

  Specifically, the coil case 1 includes a cylindrical case body 1a, a case base end 1b that houses the power feeding unit 7, a high voltage terminal 9 that receives a high voltage from the secondary coil unit 4, and a spark plug (not shown). It is comprised with the case front-end | tip part 1c holding the spring 10 etc. which transmit a high voltage | pressure.

  As shown in FIG. 2, the case base end 1b has a substantially cylindrical shape with one side (left side in FIG. 1) cut out in a rectangular shape, and a metal tube 11a on the other side (right side in FIG. 1). An interior mounting hole 11 is provided. The mounting hole 11 is used as a bolt hole when the ignition coil CL is mounted on a cylinder head such as an engine.

  A U-shaped receiving end face 12 is formed in the cutout portion of the case base end portion 1 b so as to engage with the U-shaped slide groove 7 a of the power feeding portion 7. That is, when receiving the power feeding unit 7, the slide groove 7a is slid downward while sandwiching the receiving end face 12 of the case base end 1b.

  The material of the coil case 1 having such a configuration is not particularly limited, but a thermoplastic synthetic resin such as PPS (polyphenylene sulfide) or modified PPO (modified polyphenylene oxide) is preferably used. In any case, since the coil case 1 is integrally formed using a plastic mold, a parting line 13 is formed on the contact surfaces of the plastic molds facing each other. In this embodiment, the case main body 1a is formed by facing two plastic molds from the front and back of the paper surface of FIG. 1, so that the parting line 13 is formed at the left and right positions of FIG. 1 (a). Become.

  As shown in FIG. 1 (c), the coil case 1 has a primary coil portion 3, a secondary coil portion 4 and a center core portion 5 inserted therein. The center core portion 5 is a plate having a thickness of about 0.3 mm. A central iron core 14 formed by laminating thick silicon steel plates, a protective member 15 that covers the central iron core 14 in a cylindrical shape, and a protective cap 16 that covers both ends of the central iron core 14 in the length direction. The protective cap 16 is in close contact with the central iron core 14 and the protective member 15, thereby reliably preventing the inflow of the epoxy resin 8 filled to seal the gap of the ignition coil CL.

  The secondary coil unit 4 includes a secondary bobbin 17 and a secondary winding 18 wound around the secondary bobbin 17. The primary coil unit 3 includes a primary bobbin 19, a primary winding 20 wound around the primary bobbin 19, and a cylindrical protective tape 21 covering the periphery of the primary winding 20. The outer iron core 6 is elastically fitted to the outside of the protective tape 21. The outer iron core 6, together with the central iron core 14, is optimally disposed between the primary winding 20 and the secondary winding 18. It is for forming a magnetic path.

  As shown in FIG. 3B, the exterior iron core 6 has a substantially cylindrical shape as a whole, and has a substantially C-shaped cross section in which only one portion in the circumferential direction is opened. The material of the outer core 6 having such a structure is not particularly limited as long as it is a magnetic body having elasticity that can be fitted to the primary coil portion 3, but is preferably the same material as the central core. A thin silicon steel plate is used.

  As shown in FIG. 3A, the bobbin 19 of the primary coil unit 3 includes a bobbin main body 19a around which the primary winding 20 is wound and covered with a protective tape 21, and a bobbin upper end 19b from which the primary winding 20 is drawn. And a bobbin lower end portion 19c on the high pressure side. Note that the axial length of the bobbin main body 19 a is set to be substantially the same as the axial length of the outer core 6.

  The bobbin upper end portion 19b has a two-stage configuration with a difference in height in the axial direction. The bobbin main body portion 19a is continuous with the flange 50 provided on almost the entire circumference, and the flange 50 is continuous with the half circumference. It is divided into a connecting portion 51 from which a slightly long portion protrudes. Note that the lacking portion of the flange 50 functions as the lead-out groove 29 of the primary winding 20.

  The connecting portion 51 is provided with a total of four extension arms 24A, 24B, 25A, 25B extending in the left-right direction in FIG. Cylindrical holes 26 are respectively provided on the base end sides of the extension arms 24 and 25, and the primary coil portion 3 and the power feeding portion 7 are positioned by the four cylindrical holes 26, and the primary coil portion 3. An appropriate gap is formed between the connecting portion 51 and the power feeding portion 7 to improve the flowability when the thermosetting epoxy resin 8 is filled (this point will be described later).

  A rectangular concave portion 27 is formed between the proximal ends of the adjacent extension arms 24 and 25, and the primary coil portion 3 and the secondary coil portion 4 are positioned by the concave portion 27. Yes. Further, a cylindrical portion 28 is further provided in the axial direction on the distal end side of each extension arm 24, 25 (see FIG. 3 (e)), and the primary winding 20 drawn out to the lead-out groove 29 is the cylinder. The starting point and the end point of the primary winding 20 are held by the locking piece 30 through the portion 28 (see FIG. 4A).

  FIG. 4B illustrates a top plan view of the secondary coil unit 4. As shown in FIG. 4B, the upper end portion of the bobbin 17 of the secondary coil portion has a lead-out portion 35 of the secondary winding 18 and a pair of mounting flanges 36 extending in a direction orthogonal to the lead-out portion 35. , 36 are provided. The mounting flange 36 has a size and a shape corresponding to the concave portion 27 of the bobbin 19 of the primary coil portion, and positions the secondary coil portion 4. That is, in the state where the secondary coil portion 4 is inserted into the bobbin 19 of the primary coil portion, the two mounting flanges 36 and 36 are respectively fitted in the two concave portions 27 and 27 of the primary bobbin 19, and in this state, the primary coil portion 3 and the secondary coil part 4 are positioned concentrically.

  FIG. 5 illustrates a front view (a) and a back view (b) of the power feeding unit 7. As shown in the drawing, a pair of connection terminals 38 and another connection terminal 39 are extended from the power supply unit 7. The pair of connection terminals 38 and 38 are respectively formed in an L shape with a horizontal portion 38a and a vertical portion 38b, and in a state where the power feeding portion 7 is positioned on the bobbin 19 of the primary coil portion, the two vertical portions 38b and 38b are The primary winding 20 drawn out from the primary bobbin 19 is clamped. The connection terminal 38 is connected to the primary winding 20, and the connection terminal 39 is connected to the secondary winding 18.

  Further, four engagement protrusions 37 are provided on the back surface of the power feeding unit 7. Specifically, the engagement protrusion 37 is configured by connecting a cylindrical portion 37a and a substantially conical portion 37b. The engaging protrusion 37 has a shape and a size corresponding to the cylindrical hole 26 of the bobbin upper end portion 19b of the primary coil portion 3, and the substantially conical portion 37b is immersed in the cylindrical hole 26, but the cylindrical portion 37a. Has a size that cannot enter the cylindrical hole 26.

  Therefore, when the substantially conical portion 37 b of the engagement protrusion 37 is fitted into the cylindrical hole 26 of the connecting portion 51, the primary coil portion 3 and the power feeding portion 7 are accurately positioned, and the cylinder of the engagement protrusion 37 is Due to the presence of the portion 37 a, an appropriate gap is formed between the connecting portion 51 of the primary coil portion 3 and the power feeding portion 7.

  FIG. 6 illustrates this relationship, and shows a state in which the power feeding section 7 is lowered to the connecting section 51 of the primary coil section 3 and positioned. As described above, even if the substantially conical portion 37 b of the engaging protrusion 37 is fitted into the cylindrical hole 26, a gap δ corresponding to the height of the cylindrical portion 37 a is provided between the power feeding portion 7 and the connecting portion 51. Uniformly formed. Therefore, the epoxy resin 8 before thermosetting can be smoothly introduced into the primary bobbin 19 through the gap δ.

  Next, an assembly method for the ignition coil CL having the above configuration will be described. First, the center core portion 5 is inserted into the central opening 40 (FIG. 4B) of the secondary coil portion 4. In addition, since the outer diameter of the protective cap 16 of the center core part 5 is substantially the same as the inner diameter of the central opening 40 of the secondary coil part 4, the centers of both coincide correctly.

  Subsequently, the secondary coil portion 4 in this state is inserted into the bobbin 19 of the primary coil portion 3. As described above, the two mounting flanges 36 and 36 are fitted into the two recesses 27 and 27 for positioning. Next, the power feeding part 7 is overlapped on the primary coil part 3, and the four cylindrical protrusions 37 of the power feeding part 7 are engaged with the cylindrical holes 26 of the connecting part 51 of the primary bobbin 19. In this engaged state, the gap δ is uniformly formed in the connecting portion 51 of the primary bobbin 19 as described above.

  In this engaged state, the power feeding unit 7 and the primary coil unit 3 and the secondary coil unit 4 are correctly positioned, so that the primary winding 20 is connected to the connection terminal 38 and the secondary winding 18 is connected to the connection terminal. 39. As a result of the above processing, the primary coil unit 3, the secondary coil unit 4, and the power feeding unit 7 are integrated. Therefore, the slide groove 7a of the power feeding unit 7 is slid into the receiving end face 12 of the coil case 1 so as to be integrated as a whole. (See FIG. 2). Next, after vacuuming in this state, each gap is filled with a thermosetting epoxy resin 8 and cured to fix the whole.

  As mentioned above, although the Example of this invention was described concretely, the concrete description content does not specifically limit this invention. That is, in the embodiment, the engagement protrusion 37 is provided on the back surface of the power feeding unit 7, and the cylindrical hole 26 is provided in the connecting portion 51 of the primary coil unit 3. The engaging protrusion 37 may be provided on the connecting portion 51.

  Further, the engaging protrusions are not limited to the relationship of the cylindrical holes, and are not limited to the circular shape, but may be provided with protrusions on both sides and a receiving hole on one of the protrusions. In the embodiment, four engagement protrusions and four cylindrical holes are provided, but the number is not particularly limited as long as both are the same number. However, three or more are more stable when assembled.

It is the fragmentary sectional view (a) of the ignition coil which concerns on an Example, a circuit block diagram (b), and CC sectional drawing (c). It is drawing explaining the method of attaching an electric power feeding part to a coil case. Front view (a) of primary coil part (primary bobbin), front view (b) of exterior iron core fitted to primary bobbin, AA cross-sectional view (c) of primary bobbin, plane of primary bobbin seen from high voltage side It is a figure (d) and the principal part front view (e) of the high voltage | pressure side of a primary bobbin. It is the top view (a) which looked at the primary coil part from the high voltage | pressure side, and the top view (b) which looked at the secondary coil part from the high voltage | pressure side. It is the front view (a) and back view (b) of an electric power feeding part. They are a BB sectional view (a) of an electric supply part, a front view (b) which shows an assembling method of an electric supply part and a primary coil part, and a right side view of Drawing 6 (b).

Explanation of symbols

CL ignition coil 3 primary coil part 4 secondary coil part 5 central iron core 7 feeding part 27 cylindrical hole 37 engaging projection

Claims (4)

In an internal combustion engine ignition coil comprising: a secondary coil portion in which a central iron core is inserted; a primary coil portion in which the secondary coil portion is inserted; and a power feeding portion that is disposed above the primary coil portion.
By providing an engagement protrusion protruding in the axial direction on at least one of the lower part of the power supply part that contacts the primary coil part or the upper part of the primary coil part that contacts the power supply part,
A gap is formed between the power feeding part and the primary coil part, and the positional relationship between the power feeding part and the primary coil part is fixed by the engagement protrusion. Ignition coil. The ignition coil for an internal combustion engine according to claim 1, wherein three or more engagement protrusions are provided. In response to the engagement protrusion being provided on one side of the primary coil part and the power feeding part, the other side of the primary coil part and the power feeding part receives part of the engagement protrusion. The ignition coil for an internal combustion engine according to claim 1 or 2, wherein a portion is formed. The motor vehicle which incorporates the ignition coil in any one of Claims 1-3.

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