JP2009267046A - Ignition system of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ignition system of an internal combustion engine for suppressing a decrease in performance and preventing a steep rise in costs by realizing the manufacture of an exterior core conforming to dimensional tolerance. <P>SOLUTION: In the exterior core 140 used for the ignition system of an internal combustion engine, cut surfaces Ac-Dc are formed at corners A-D of a silicon steel plate, and top sections Ah1-Dh1 formed by the cut surfaces Ac-Dc and an axial side h2 are arranged at end points P and Q for prescribing an axial length Ha1 in the exterior core, thus bringing the axial length Ha1 in the exterior cores 140 or 240 closer to design dimensions. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an ignition device for an internal combustion engine, and is particularly suitable for use in improving the dimensional accuracy of an exterior iron core.

  An ignition device used in an internal combustion engine is fixed in a state where an ignition coil is inserted into a plug hole. Such an ignition coil has a coil assembly disposed in a coil case, and the coil assembly is configured by arranging a secondary coil and a primary coil in an annular shape outside the central iron core, thereby forming a transformer. An electromagnetic circuit is formed. Further, in such an ignition device, an outer iron core is further arranged on the outer periphery of the coil assembly to enhance the performance of the electromagnetic circuit.

  The exterior iron core used here is formed by rolling a sheet-shaped silicon steel sheet into a substantially cylindrical shape. In addition to the single layer type outer iron core made of only one silicon steel plate, the outer iron core has various forms of outer iron such as a multilayer type outer iron core obtained by laminating and rolling a plurality of silicon steel plates. A wick is being considered.

  Japanese Patent Laid-Open No. 11-265833 (Patent Document 1) introduces an example of an ignition coil having an exterior iron core. Such an ignition coil includes an open magnetic circuit core (a central iron core in claims), a primary coil and a secondary coil, and an exterior iron core. And since this exterior iron core serves also as the cylindrical part of a coil case, the internal diameter part in a coil case is ensured widely, Thereby, in this ignition coil, the number of turns of a primary coil and a secondary coil, and a winding ratio It is optimized and the output energy is improved.

JP-A-11-265833

  However, as shown in FIG. 6 (a), when the orientation iron core used in the ignition device is oriented between the feed direction when the silicon steel plate is guided to the roll processing machine and the reference line of the silicon steel plate, A deviation angle θ occurs with respect to the reference line AB or the reference line DC. In such a case, since the silicon steel sheet is rolled along the roll direction AB ′ and the roll direction DC ′, the short side H does not coincide with the corner A and the corner B as shown in FIG. It is formed into a cylindrical body distorted in the direction.

  Therefore, in the case of the exterior iron core processed as described above, as shown in FIG. 6B, the axial length Ha of the exterior iron core increases correspondingly and conforms to the range of dimensional tolerance required in the design. The problem of not going to occur.

  In addition, when using a grain-oriented silicon steel sheet that has the property of being easily magnetized only in one direction, the grain-oriented silicon steel sheet has a large deformation caused after plastic working because the internal structure is composed of large crystal grains. As described above, the deformation in the axial direction appears remarkably, and this also causes a problem that the size tolerance range required in the design is not met.

  And when the exterior iron core larger than this dimensional tolerance is used for an ignition device, the problem of deteriorating electromagnetic characteristics by the residual stress which has arisen in the said exterior iron core is induced. In particular, when the internal combustion engine is driven and a high amount of heat is supplied, thermal stress is generated in the outer iron core, and the electromagnetic characteristics are significantly deteriorated.

  Further, when used in an ignition device in which an exterior iron core is housed inside a coil case, cracks may occur in the epoxy resin filled inside due to corners appearing at the ends of the exterior iron core. Moreover, when using for the ignition device which arranged the armored iron core on the outer periphery of the coil case, if both ends of the armored iron core are positioned by the coil case, a compressive force acts on the axially inner side of the armored iron core. When the compression action proceeds, there is a concern that the dimension in the radial direction of the outer iron core may increase.

  In addition, if an exterior iron core that deviates from the dimensional tolerance is manufactured at a high frequency, it cannot be used as a part of the ignition device, thereby causing a problem that the cost of the ignition device is increased.

  Accordingly, in view of the above problems, the present invention has an object to provide an ignition device for an internal combustion engine that can suppress a decrease in performance and prevent an increase in cost by realizing the manufacture of an exterior iron core that conforms to dimensional tolerances. To do.

  In order to solve the above problems, the present invention has the following configuration of an ignition device for an internal combustion engine. That is, in an ignition device for an internal combustion engine, comprising: a coil assembly that boosts an input voltage; a coil case that stores the coil assembly; and an outer iron core obtained by rolling a substantially rectangular silicon steel plate into a cylindrical shape. The steel sheet has a cut surface formed in at least one corner, and the outer iron core has the cut surface and the axial side at one or both of the end points that define the axial length of the outer iron core. The intersection formed by the top or the cut surface and the periphery of the circle is formed.

  At this time, the cut surface may be formed at a diagonal position of the silicon steel plate among the corner portions, and the cut surface may be formed at all of the corner portions.

  Moreover, it is preferable that the cut angle that forms an acute angle by the line of intersection between the cut surface and the periphery of the circle is equal to or greater than the angle of deviation that occurs when the silicon steel sheet is rolled.

  In the armor core according to the present invention, even when distortion occurs due to the deviation angle caused by roll processing or the crystal grain of the silicon steel sheet, the end point that defines the axial length by the top or intersection of the cut surface Is appropriately set, and thereby the axial length of the outer iron core is adjusted so as to approach the design dimension of the silicon steel sheet.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, a cross-sectional structure of an internal combustion engine ignition device (hereinafter referred to as an ignition device) will be described with reference to FIG. As shown in FIG. 1A, the ignition device 10 includes a coil case 110, a coil assembly 120, a high voltage terminal 130, an exterior iron core 140, and an igniter 150.

  In the coil case 110, a head portion 110a, a coil storage portion 110b, and a plug connection portion 110c are integrally formed. The head 110a is provided with a fitting portion for fitting the igniter 150 and an insertion hole for inserting the connection bolt. Inside the head 110a, when the igniter 150 is fitted, a space having an opening at the top is formed. The connection bolt passed through the insertion hole is screwed into a female screw tap formed near the plug hole of the engine head, and fixes the coil case 110a inserted through the plug hole to the engine head. Further, the coil storage portion 110b is formed in a cylindrical body and stores the coil assembly 120. As shown in the figure, the coil housing portion 110b is provided with an igniter 150 at one end and a high voltage terminal 130 at the other end. The plug connecting portion 110c electrically connects the high voltage terminal 130 and the spark plug head when the spark plug head is connected.

  The coil assembly 120 includes a central iron core 120a, a secondary coil 120b, and a primary coil 120c, and boosts the input voltage applied from the igniter 150 by the action of electromagnetic induction. The central iron core 120a is formed by stacking silicon steel plates having different plate widths to form a substantially cylindrical body. The secondary coil 120 b has a secondary winding wound around an insulating bobbin, one end grounded to the ground, and the other end connected to the high voltage terminal 130. The primary coil 120 c has a primary winding wound around a primary bobbin, one end is connected to a power supply terminal arranged on the side wall of the igniter 150, and the other end is connected to a ground terminal arranged on the side wall of the igniter 150. . The coil assembly 120 and the outer iron core 140 constitute an electromagnetic circuit as a transformer.

  The exterior iron core 140 is processed from a silicon steel plate having a substantially rectangular shape having a predetermined thickness, and is rolled into a substantially cylindrical shape by a roll processing machine. As illustrated, the exterior iron core 140 is positioned within a range defined by the high-pressure side protrusion 120f. At this time, since the gap at the upper end portion is narrowed, it is preferable that the outer iron core 140 is molded within a predetermined dimensional tolerance range.

  FIG. 2 shows an example of the exterior iron core 140 used in the present embodiment. However, the external iron core 140 that can be used in the present embodiment is not limited to such an embodiment, and may be a multi-layered external iron core in which a plurality of silicon steel plates are laminated. Moreover, it can be set as the various forms mentioned later.

  Returning to FIG. 1, the igniter 150 will be described. The igniter 150 includes a connector unit 150a and a circuit storage unit 150b. The connector unit 150a is appropriately provided with a connection terminal, and receives a power supply voltage, a drive signal, or the like, and grounds predetermined power in the primary coil 120c and the igniter to the ground. The circuit storage unit 150b stores a control circuit on which a power switching element or other electrical element is mounted. In such a control circuit, a functional circuit such as a signal generation circuit, a self-shutoff circuit, or an ion current detection circuit is appropriately configured by various electrical elements.

  In the ignition device 10 having such a configuration, when a drive signal is input to the connector portion 150a of the igniter 150, the power supply voltage supplied to the igniter 150 is applied to the coil assembly 120 at an appropriate timing. At this time, the coil assembly 120 boosts the power supply voltage and applies the boosted voltage boosted in this way to the high-voltage terminal 130. Therefore, in the spark plug connected to the ignition device 10, a boosted voltage is applied via the high voltage terminal 130, and discharge occurs in the plug gap laid out in the cylinder of the engine block.

  On the other hand, FIG. 1B shows another ignition device different from the configuration of the ignition device described above. In the ignition device 20, the exterior iron core 240 is inserted into the outside of the coil housing portion 110 b. And in the coil case 110b, the low voltage | pressure side protrusion 220e and the high voltage | pressure side protrusion 220f are formed, and the exterior iron core 240 is positioned in the range prescribed | regulated by the low voltage | pressure side protrusion 220e and the high voltage | pressure side protrusion 220f. Therefore, even in such an exterior iron core 240, a predetermined dimensional tolerance is required as described above. In addition, about another structure, it is the same as that of the ignition device 10 shown to Fig.1 (a).

  FIG. 3 (a) shows a silicon steel plate before roll processing. That is, in this figure, a development view of a substantially cylindrical body is shown. In the figure, the silicon steel sheet according to the present example is shown by a solid line in the shape immediately before being rolled. Further, in the silicon steel plate according to the conventional example shown in FIG. 6, a rectangular body connecting the corners A to D is indicated by a broken line. Such a rectangular body is composed of a short side H (designed size or a size close to this) and a long side R, and each corner has a substantially right angle. Further, in the figure, a line segment AB ′ and a line segment DC ′ indicate the feed direction of the roll processing machine when a processing error in roll processing occurs.

  First, the process of processing a silicon steel plate will be described. The silicon steel sheet is sequentially processed by a press machine and a roll machine, and formed into an outer iron core 140 or 240. Specifically, first, the silicon steel sheet sent to the press machine has the apexes at the tops Ah1, Bh1, Ch1, Dh1 and the intersections Ar1, Br1, Cr1, Dr1, as indicated by solid lines 8. Die cut into squares. At this time, each vertex may be appropriately R-processed. Moreover, according to the surface shape of the ignition device 20, you may form an appropriate slit in line segment Ar1-Br1 or line segment Dr1-Cr1. The silicon steel sheet formed as described above will be described in detail. In the silicon steel sheet, cut surfaces Ac to Dc are formed on a rectangular body composed of corners A, B, C, and D. Here, it is assumed that the line segments Ar1 to Br1 and the line segments Dr1 to Cr1 are referred to as a circle periphery r2, and the line segments Ah1 to Dh1 and the line segments Bh1 to Ch1 are referred to as an axial side h2. The top portions Ah1 to Dh1 are formed by intersecting lines of the cut surfaces Ac to Dc and the axial side h2. Further, the intersecting portions Ar1 to Dr1 are formed by intersecting lines between the cut surfaces Ac to Dc and the circle periphery r2. Here, an acute cut angle α is formed at the intersection line between the cut surfaces Ac to Dc and the circle periphery r2. The cut width h1 formed by the cut angle α is preferably about 1 mm. At this time, the cut width r1 is determined by the cut angle α and the cut width h1.

  When the processing process by the press machine is completed, the silicon steel sheet is sent to the roll machine and rolled so as to be arcuate in the direction of the long side R, whereby the axial side h2 is set in the axial direction of the cylindrical body. The exterior iron core 140 or 240 is formed. Note that the short side H in the virtual quadrangle ABCD may be shorter than the long side R, and conversely, may be longer than the long side R.

  The shift angle θ shown in the figure occurs when, for example, the direction of the long side R is oriented in a direction different from the feed direction of the silicon steel sheet. Therefore, on the long side R, it is preferable that the line segments Ar1 to Br1 and Dr1 to Cr1 that are not chamfered remain as reference lines. Thereby, the shift | offset | difference angle | corner (theta) produced when rolling a silicon steel plate is reduced, and the processing error at the time of roll processing is suppressed.

  As shown in FIG. 3 (a), when a deviation angle θ occurs during roll processing, the silicon steel sheet is rolled along a line segment AB ′ and a line segment DC ′ that are in the direction of the deviation angle θ. . Therefore, as shown by the solid line part in FIG. 3B, when the silicon steel sheet is rolled in such a state, the top part Ah1 and the top part Bh1 or the top part Ch1 and the top part Dh1 do not coincide with each other, and the circle periphery r2 becomes A spiral curve with a minute pitch is formed. More specifically, the rolled cylindrical silicon steel sheet has a spiral curve formed at both ends in a three-dimensional manner as shown in the figure, so that the cylindrical body is slightly stretched in the direction of the axial side h2. It is said. In the cylindrical body having such a shape, the axial length Ha1 of the outer core 140 or 240 is defined by the distance between the end point P and the end point Q. At this time, the apex Bh1 is arranged at the end point P, and the apex Dh1 is arranged at the end point Q. The top portion Bh1 and the top portion Dh1 correspond to the diagonal positional relationship in □ ABCD. That is, when the misalignment angle θ is negative, the top portion Ah1 and the top portion Ch1, which are other combinations having a diagonal position relationship, are arranged at the end point P and the end point Q.

  Moreover, in FIG.3 (b), the shape of the silicon steel plate when not chamfering is shown with the broken line. In such a conventional exterior iron core, the axial length Ha is defined by the top portions B and D.

  Therefore, when comparing the axial length Ha1 of the armored iron core according to the present example and the axial length Ha1 of the armored iron core according to the conventional example, as illustrated, the axial length Ha1 of the present example is It can be seen that the axial length Ha of the conventional example is shorter by 2 × Hb1. In the figure, θ> α is set, so that the axial length Ha1 is longer than the short side R of the silicon steel plate. That is, in this case, the axial length Ha1 is adjusted in the range of H <Ha1 <Ha.

  Further, it is preferable that the cut angle α that forms an acute angle by the line of intersection between the cut surface and the periphery of the circle is larger than the shift angle θ. In such a case, referring to FIG. 3 (a), since ∠ (Bh1-Br1-Cr1) and ∠ (Dh1-Dr1-Ar1) are at an angle of 90 ° or less, the top portion Ah1 and the top portion Dh1 are inside the cylindrical body. Dive into. At this time, the end point P that defines the axial length Ha1 is a position where the intersecting portion Br1 is disposed. On the other hand, the end point Q that defines the axial length Ha1 is a position where the intersecting portion Dr1 is disposed. As a result, the axial length Ha1 when θ <α can be made closer to the length of the short side H of the silicon steel sheet more effectively than the axial length Ha1 when θ> α. Further, the cut angle α and the shift angle θ may be the same angle.

  In the present embodiment, the case where distortion occurs due to the deviation angle θ generated in roll processing has been described. However, the present invention is not limited to this, and even when distortion occurs due to the influence of the crystal grains of the silicon steel sheet, the amount of distortion is reduced. By predicting in advance, the axial length Ha1 of the outer iron core 140 or 240 is brought close to the length of the short side H.

  In the external iron core 140 or 240 according to the present embodiment, even when distortion occurs due to the deviation angle θ generated by roll processing, as shown in FIG. 2, the top portions Ah1 to Dh1 or the intersecting portions Ar1 of the cut surfaces Ac to Dc. ~ Dr1 appropriately sets the end point P and the end point Q that define the axial length Ha1, and thereby adjust the axial length Ha1 of the outer iron cores 140 and 240 to approach the design dimensions of the silicon steel sheet Is done.

  Further, in the exterior iron core 140 or 240 according to the present embodiment, even when the distortion occurs due to the influence of the crystal grain of the silicon steel plate, the end point P and the end point Q that define the axial length Ha1 are the same as described above. Accordingly, the axial length Ha1 of the outer iron cores 140 and 240 is adjusted so as to approach the design dimension of the silicon steel sheet.

  Further, when the exterior iron core 140 is used in the ignition device 10 housed in the coil case 110, the protrusion shape appearing at the end P or Q of the exterior iron core 140 approaches an obtuse angle, so that the epoxy resin filled inside The cracks that occur in are also reduced. Further, when the exterior iron core 240 is used in the ignition device 20 arranged on the outer periphery of the coil case 110, the axial length Ha1 approaches the design dimension, so that the compressive force does not work inward in the axial direction of the exterior iron core. The dimension in the radial direction of the iron core is maintained at an appropriate value.

  Moreover, in this Embodiment, since cut surface Ac-Dc is each formed in all the corner | angular parts AD, regardless of the direction of the gap angle produced when a silicon steel plate is roll-processed, an exterior iron core The axial lengths Ha1 of 140 and 240 are adjusted so as to approach the short side H of the silicon steel plate.

  As shown in FIG. 4 (a), the cut surface to be processed into the silicon steel plate may be formed at corners A and C arranged at diagonal positions of the silicon steel plate among the corners A to D. Here, the roll start position of the silicon steel sheet is defined as a line segment AD, the roll end position of the silicon steel sheet is defined as a line segment BC, and the long side R in the vicinity of the roll direction AB ′ passing through the silicon steel sheet by the deviation angle θ is defined as Assume that the long side R in the vicinity of the roll direction DC ′ passing through the outside of the silicon steel sheet by the deviation angle θ is the line segment DC (reference line) with the line segment AB (reference line). In this case, the cut surface Ac is formed at the intersection of the line segment AD and the line segment AB. The remaining cut surface Cc is formed at the intersection of the line segment BC and the line segment DC. As shown in the figure, the cut surface Ac and the cut surface Cc are located diagonally to the □ ABCD. Even in the case of an exterior iron core processed from such a silicon steel plate, the axial length Ha1 is adjusted so as to approach the short side H of the silicon steel plate, as shown in FIG.

  Furthermore, as shown in FIG. 5, the cut surface to be processed into the silicon steel plate is only one of the corner portion A or the corner portion C arranged at the diagonal position of the silicon steel plate among the corner portions A to D. It may be formed. Even in such a case, as shown in FIG. 5B, the axial length Ha1 is adjusted so as to approach the short side H of the silicon steel sheet. However, the axial length Ha1 is reduced only by Hb1 with respect to the axial length Ha of the conventional example.

The figure which shows the structure of the ignition device of the internal combustion engine which concerns on this Embodiment The figure which shows the exterior iron core which concerns on this Embodiment. The figure explaining an example of the cut surface formed in the exterior iron core The figure explaining the other example of the cut surface formed in the exterior iron core The figure explaining the other example of the cut surface formed in the exterior iron core The figure explaining the shape of the exterior iron core concerning a prior art example

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Internal combustion engine ignition device 110 Coil case 120 Coil assembly 120d Exterior iron core h2 Axial side r2 Circle periphery A to D Corner
P end point
Q End point Ac to Dc Cut surface Ah1 to Dh1 Top part Ar1 to Dr1 Top part
α Cut angle
θ Deviation angle

Claims (4)

In an ignition device for an internal combustion engine, comprising: a coil assembly that boosts an input voltage; a coil case that stores the coil assembly; and an outer iron core that is formed by rolling a substantially rectangular silicon steel plate into a cylindrical shape.
The silicon steel sheet has a cut surface formed in at least one corner,
The exterior iron core is formed by one or both of end points that define the axial length of the exterior iron core by a top portion formed by the cut surface and the axial side or the cut surface and the periphery of the circle. An ignition device for an internal combustion engine, characterized in that an arranged intersection is arranged.   The ignition device for an internal combustion engine according to claim 1, wherein the cut surface is formed at a diagonal position of the silicon steel plate in the corner portion.   The ignition device for an internal combustion engine according to claim 1, wherein the cut surface is formed on all of the corners.   The cut angle that forms an acute angle by the intersecting line between the cut surface and the periphery of the circle is equal to or greater than the angle of the deviation angle that occurs when the silicon steel sheet is rolled. An ignition device for an internal combustion engine as described.

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