JP2015065422A - Ignition coil device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly reliable ignition coil device in which cracks are hard to occur in a circuit housing portion and allows achieving stable control.SOLUTION: An ignition coil device 1 includes an ignition coil and a circuit module 20 controlling supply and cutoff of a voltage to the ignition coil that are housed inside a housing 30 and are sealed with an insulating resin 40. The housing 30 includes a wide portion 301 formed to a width W1 capable of housing the ignition coil with respect to a width direction of the circuit module 20, a narrow portion 311 constituting a circuit housing portion 31 for housing the circuit module 20 and formed to a width W2 narrower than the wide portion 301, and a connection portion 302 connecting the wide portion 301 and the narrow portion 311. A peeling member 50 having relatively low adhesiveness against the insulating resin 40 is inserted between the circuit module 20 and an inner peripheral corner portion 313 where the narrow portion 311 and the connection portion 302 are crossed.

Description

  The present invention relates to an ignition coil device for supplying a high voltage to an ignition plug for an internal combustion engine.

  In Patent Document 1, a case and at least a part of an iron core composed of a central iron core and an outer peripheral iron core are accommodated in the case, and a primary winding is wound around a primary bobbin in the case. An ignition coil for an internal combustion engine that houses a secondary coil and a secondary coil in which a secondary winding is wound around a secondary bobbin, and the coil housing portion in the case is filled with mold resin. A magnetic path of the iron core is disposed in a direction perpendicular to the opening surface of the case, the outer iron core side coil facing surface of the outer iron core is provided with a tape that peels from the mold resin, and the outer iron core side coil facing surface. An internal combustion engine comprising a protrusion on a horizontal extension of the outer peripheral iron-side coil facing surface and a tape that peels off from the mold resin, and the protrusion is provided at a position lower than the resin surface of the mold. An ignition coil device is disclosed That.

As a comparative example 1, in the conventional ignition coil device 1z shown in FIG. 6A, a part of the side iron core 14 covered with a core cover 15 made of a mold resin such as PET resin or PBT resin is part of the insulating resin 40z. Exposed outside.
On the other hand, the lower side of the side iron core 14 and the central iron core 10 are sealed and fixed by an insulating resin 40z filled in the housing 30z.
Further, the resin-molded circuit module 20 is accommodated in the vicinity of the connector 32 in the housing 30z, and is sealed and fixed by the insulating resin 40z.

In the ignition coil device 1z having such a structure, a part of the side iron core 14 is exposed to the outside, and the upper surface of the housing 30z is greatly opened, so that the binding force of the insulating resin 40z on the side iron core 14 is weak. Also, the thermal stress is low, and the core cover 15 and the surrounding insulating resin 40z are hardly cracked.
For this reason, as disclosed in Patent Document 1, even if a peelable tape is interposed between the secondary coil 12 and the side iron core 14, the effect of preventing cracking of the core cover 15 and the insulating resin 40z is small. Conceivable.

  On the other hand, in recent years, in order to stabilize ignition in a difficult-to-ignite internal combustion engine, the circuit module 20 is required to have high-precision control performance, and a power MOSFET, IGBT, etc. that can supply a large amount of energy. The amount of heat generated from the circuit module 20 tends to increase.

However, in the structure of the conventional ignition coil device 1z, as shown as Comparative Example 1 in FIG. 6C, the volume of the insulating resin 40z covering the periphery of the circuit module 20z is large, and the resin portion has a lower thermal conductivity than metal. There is a risk that the control stability of the circuit module 20 is reduced due to heat storage.
Further, in the conventional ignition coil device 1z, heat generated in the circuit module 20z is radiated exclusively by heat conduction via the lead 21z drawn out from the circuit module 20z.
For this reason, as the amount of heat generated from the circuit module 20z increases, the thermal stress on the lead 21z increases, leading to poor connection with the connector terminal 22z, disconnection, and the like, which may reduce the reliability of the ignition coil device 1z. It was.

  Therefore, as Comparative Example 2, as shown in FIG. 6D, by reducing the volume of the circuit housing portion 31 y according to the size of the circuit module 20, direct heat dissipation from the circuit module 20 to the outside. It was considered that heat radiation can be performed and the heat radiation path is dispersed, thereby reducing the thermal stress on the lead 21y and at the same time stabilizing the control of the circuit module 20.

JP 2012-146896 A

However, in the ignition coil device 1y of the comparative example 2, it is possible to radiate the heat directly from the circuit module 20 to the outside through the circuit housing portion 31y, but as shown on the right side of FIG. The circuit housing portion 31y receives the thermal stress from the circuit module 20.
In particular, since stress concentrates on the inner peripheral side corner 313y where the connecting portion 302y connecting the wide portion 301 of the housing and the narrow portion 311y constituting the circuit accommodating portion 31y and the narrow portion 311y intersect, It has been found that there is a possibility of causing a crack from the portion 313y toward the outer peripheral side corner portion 314y.

  Therefore, the present invention has been made in view of such circumstances, and in the ignition coil device, a narrow portion in which the lateral width of the housing is partially narrowed is provided to accommodate the circuit module in order to improve the heat dissipation of the circuit module. When the circuit housing part is used, the connecting part that connects the wide part of the housing and the narrow part of the circuit housing part is less likely to crack at the inner peripheral corner where the narrow part intersects, and stable control can be realized. An object of the present invention is to provide a highly reliable ignition coil device.

In the present invention (1, 1a, 1b, 1c, 1d, 1e, 1f), at least a primary coil (11), a secondary coil (12), and a central core (inside the primary coil (11)) ( 10), a side iron core (14) disposed outside the secondary coil (12), and an ignition coil (100), and a circuit module for controlling supply and interruption of voltage to the coil (100) (20) is an ignition coil device that is housed inside the housing (30) and sealed with an insulating resin (40),
The housing constitutes a wide portion (301) formed in a lateral width (W1) capable of accommodating the ignition coil with respect to a lateral width direction of the circuit module, and a circuit accommodating portion (31) for accommodating the circuit module. A narrow portion (311) formed in a lateral width (W2) narrower than the wide portion, and a connecting portion (302) connecting the wide portion and the narrow portion, and the narrow portion, A peeling member (50, 50a to 50g) having relatively weak adhesive force to the insulating resin is interposed between the inner peripheral side corner portion (313) where the connecting portion intersects and the circuit module. Features.

According to the present invention, by interposing the peeling member between the circuit module and the inner peripheral corner, the binding force between the insulating resin and the circuit housing portion is weakened, The stress is relieved, and it is possible to prevent the housing from cracking from the inner peripheral corner to the outer peripheral corner (314).
As a result of intensive studies by the inventors, when the width (W3) of the circuit module is 63% or more and 100 (%) or less with respect to the width (W2) of the narrow portion, the stress concentration on the inner peripheral side corner is reduced. It becomes prominent and exceeds the fatigue limit of the mold resin constituting the housing, and may cause cracking, but by interposing the peeling member, stress concentration on the inner peripheral side corner portion is alleviated, It has been found that the occurrence can be prevented.
It was also found that the stress relaxation effect of the peeling member can be exhibited by setting the width (T2) of the peeling member in the thickness direction of the circuit module to 60% or more of the thickness (T1) of the circuit module.

The perspective view of the ignition coil apparatus 1 in the 1st Embodiment of this invention. 1A is a top view of the ignition coil device 1 of FIG. 1A. Sectional drawing of the ignition coil device 1 of FIG. 1A A bottom view of the ignition coil device 1 of FIG. 1A Cross-sectional view of main parts along AA in FIG. 1C Sectional drawing of the principal part along BB in FIG. 1C The modification 1b of the ignition coil apparatus in 1st Embodiment is shown, The left side is sectional drawing along AA, The right side is sectional drawing along BB Sectional drawing of the principal part of the ignition coil apparatus 1c in 2nd Embodiment. Sectional drawing of the principal part of the modification 1d of the ignition device in 2nd Embodiment Sectional drawing of the principal part of the ignition coil apparatus 1d in 3rd Embodiment. Sectional drawing which shows the principal part which shows the modification 1e of the ignition coil apparatus in 3rd Embodiment. Sectional drawing of the principal part of the ignition coil apparatus 1f in 4th Embodiment. Sectional drawing which shows the principal part which shows the modification 1g of the ignition coil apparatus in 4th Embodiment. The perspective view of the conventional ignition device 1z shown as the comparative example 1 The perspective view of the ignition device 1y which reduced the circuit accommodating part shown as the comparative example 2 Cross-sectional view of relevant parts showing problems in Comparative Example 1 Cross-sectional view of relevant parts showing problems of Comparative Example 2 Characteristic diagram showing the results of thermal stress analysis by the finite element method Characteristic diagram showing change in maximum principal stress depending on width ratio W3 / W2 between narrow part of housing and circuit module Characteristic diagram showing the effect of peeling member on maximum principal stress Characteristic diagram showing change of maximum principal stress by width ratio W2 / W1 of wide part and narrow part of housing Characteristic diagram showing the effect of the height ratio H2 / H2 between the wide part and narrow part of the housing on the maximum principal stress

With reference to FIG. 1A, FIG. 1B, FIG. 1C, FIG. 1D, and FIG. 1E, the outline | summary of the ignition coil apparatus 1 of this invention is demonstrated.
The ignition coil device 1 according to the present invention includes a primary coil 11, a secondary coil 12, a central iron core 10 disposed inside the primary coil 11, a side iron core 14 disposed outside the secondary coil 12, and a central iron core 10. And the permanent magnet 13 disposed in the gap between the side core 14 and the ignition coil 100, the circuit module 20 for controlling the supply and interruption of the current to the primary coil 11, and the leads of the primary coil 11 and the circuit module 20 A connector terminal 22 for connecting the portion 21 to the outside, an output relay terminal 120 for connecting the output end of the secondary coil 12 and a spark plug (not shown), a high voltage terminal 121, and a spring terminal 122 are provided in the housing 30. And sealed with an insulating resin 40.

In the ignition coil device 1 of the present invention, the volume of the circuit housing portion 31 that houses the circuit module 20 of the housing 30 is reduced according to the size of the circuit module 20, and heat can be easily radiated from the circuit module 20 to the outside. It has a structure.
The housing 30 constitutes a wide portion 301 formed in a lateral width W1 that can accommodate the ignition coil 100 and a circuit accommodating portion 31 that accommodates the circuit module 20 in the lateral width direction of the circuit module 20. A narrow portion 311 having a narrow lateral width W2 and a connecting portion 302 that connects the wide portion and the narrow portion.
Further, between the circuit module 20 and the circuit housing part 31, in particular, the inner peripheral side corner part 313 where the narrow part 311 of the circuit housing part 31 and the coupling part 302 easily cause stress concentration and the side surface of the circuit module 20. A separating member 50 having low adhesion to the insulating resin 40 is interposed between the two.

An epoxy resin, a urethane resin, or the like is used for the insulating resin 40, and a resin such as silicone, polypropylene, polyamide, polyimide, nylon, or fluorine that has low adhesion to the epoxy resin is used for the peeling member 50.
The release member 50 was coated with a release agent such as a silicone resin on the surface of a base material formed of a heat-resistant resin in a sheet form, and a pressure sensitive adhesive such as a rubber adhesive or a silicone adhesive was applied on the back side. A tape-shaped member may be used.
In the above description, it is expressed that a resin having low adhesion to the epoxy resin is used for the peeling member 50, but this acts between the peeling member 50 and the epoxy resin constituting the insulating resin 40. Between the other members (for example, the resin constituting the housing 30, the primary bobbin 111, the secondary bobbin 121, the metal constituting the side iron core 14) and the epoxy resin constituting the insulating resin 40. It means that it is relatively lower than the adhesive force acting on the substrate, and does not indicate the substrate of the peeling member.

Moreover, the pasting workability can also be improved by using a tape-like silicone film or the like whose base material is PET.
In this embodiment, as shown in FIG. 1E, a peeling member 50 made of a tape-like silicone film is attached along the inner side surface of the inner peripheral side corner portion 313 of the circuit housing portion 31.
In particular, by using a tape member such as a tape-like silicone film with an adhesive on the back surface, it is possible to attach the inside of the element accommodating portion 31 very easily.

In general, the surface of such a resin tape is subjected to silicone treatment on the surface side to improve the releasability, and exhibits high releasability even for the insulating resin 40.
In addition, since the adhesive applied to the back side of the resin tape has viscoelasticity, in addition to the peelability of the silicone tape, the mold resin and the insulating resin 40 constituting the circuit module 20 are formed by the viscoelasticity of the adhesive. It is considered that the thermal stress due to the difference in thermal expansion coefficient between the element accommodating portion 31 and the insulating resin 40 can be suppressed.

As shown in FIG. 1B and FIG. 1D, the attaching range of the peeling member 50 is a range facing the side surface of the circuit module 20 or a range longer than that.
According to the inventor's earnest test, when the width W3 of the circuit module 20 with respect to the width W2 of the narrow portion 311 is 63% or more and 100% or less, the stress concentration on the inner peripheral side corner 313 becomes remarkable, and the housing 30 It has been found that there is a risk that cracks may occur from the inner peripheral side corner 313 toward the outer peripheral side corner 314 beyond the fatigue limit of the mold resin that constitutes the mold.
However, it has been found that by interposing the peeling member 50 between the circuit module 20 and the inner peripheral corner portion 313, stress concentration on the inner peripheral corner portion 313 can be alleviated and cracking can be prevented.
Further, it was found that the stress relaxation effect of the peeling member 50 can be exhibited by setting the width T2 of the peeling member in the thickness direction of the circuit module 20 to 60% or more of the thickness T1 of the circuit module 20.
By affixing the peeling member 50 to the inner peripheral side corner 313 of the circuit housing portion 31, the binding force between the inner peripheral side corner 313 and the insulating resin 40 is weakened, the thermal stress is relaxed, and the inner peripheral side corner is reduced. It is possible to prevent the portion 313 from cracking outward.

In addition, as shown in FIG. 1F, a peeling member 51 having low adhesion to the insulating resin 40 may be interposed between the central core 10 and the inner peripheral side corner portion 313 of the circuit housing portion 31. .
By adopting such a configuration, not only thermal stress due to heat generation from the circuit module 20 but also thermal stress due to heat generation of the central iron core 10 due to energization to the ignition coil 100 is concentrated on the inner peripheral side corner 313. It is possible to suppress the occurrence of cracks in the inner peripheral side corner 313.

In the present embodiment, an example in which the peeling members 50 and 51 are provided separately is shown, but the peeling member 50 and the peeling member 51 may be continuously formed with a single silicone tape.
Moreover, if the peeling member 50 is provided so as to cover the inner peripheral side corner portion 313 of the circuit housing portion 31 at least at a position facing the side surface of the circuit module 20 where the thermal stress is large, the effect of the present invention can be exhibited. .

Hereinafter, a general configuration of the ignition coil device 1 according to the present invention will be described.
A primary winding 110 is wound around the primary bobbin 111 a predetermined number of times N1 to form the primary coil 11.
One end of the primary coil 11 is connected to a power supply (not shown) provided outside via a connector terminal 22.
The other end of the primary coil 11 is connected to a predetermined lead portion 21 of the circuit module 20.

A secondary winding 120 is wound around the secondary bobbin 121 a predetermined number of times N2 to form the secondary coil 12.
One end of the secondary coil 12 is connected to one end of the primary winding 11 via a diode 16.
The other end of the secondary coil 12 is connected to an output relay terminal 122, a high voltage terminal 123, and a spring terminal 124, and can be connected to a center electrode of a spark plug provided in the internal combustion engine.

For the primary winding 110 and the secondary winding 120, a known insulated wire is used in which the surface of a conductor such as copper or aluminum is insulated with enamel, polyurethane, polyester or the like.
The primary coil 11 and the secondary coil 12 are arranged concentrically, the central iron core 10 is arranged inside the primary coil 11, and the side iron core 14 is arranged outside the secondary coil 12.

A part of the side iron core 14 is covered with a core cover 15 made of resin.
A part of the core cover 15 is exposed from the surface of the insulating resin 40.
The central iron core 13 is formed by stacking a plurality of band-shaped silicon steel plates into a columnar shape, and constitutes an exciting core.
The side iron core 14 is formed by laminating a plurality of U-shaped silicon steel plates and fixing them by caulking.
A permanent magnet 13 is disposed in the gap between the side iron core 14 and the central iron core 10.
A closed magnetic circuit is formed by the cooperation of the side iron core 14 and the central iron core 10.

The core cover 15 is made of a mold resin material such as PET resin or PBT resin, and is made of a fiber reinforced resin to which fibers for improving mechanical strength are added or a heat dissipation improving resin to which heat dissipation filler is added to improve heat dissipation. It may be used.
A part of the core cover 15 is exposed to the outside from the surface of the insulating resin 40.
By exposing a part of the core cover 15 from the surface of the insulating resin 40, the heat dissipation is improved and the thermal stress is easily released, and the core cover 15, the insulating resin 40, the housing 30 and the like are cracked. It is hard to produce.

Inside the connector 32 provided in the housing 30, an input end of the primary coil 11 and a connector terminal 22 for connecting the igniter 20 to the outside are arranged so as to be connected to a power source and a control device (not shown). It has become.
In addition, a cylindrical plug cap 33 is extended in the housing 30 so that it can be attached to an unillustrated spark plug provided in the internal combustion engine.
Inside the plug cap 33, a spring terminal 122 connected to the output end of the secondary winding 12 through the output relay terminal 120 and the high voltage terminal 121 is disposed.

The step-up coil 100 housed inside the housing 30 is disposed so that a part of the core cover 15 covering the side iron core 14 is exposed, and is sealed and fixed by an insulating resin 40.
As the insulating resin 40, an epoxy resin or the like is used, and a fiber reinforced resin to which fibers for improving mechanical strength are added or a resin to which heat radiating filler for improving heat dissipation is added may be used.

The circuit module 20 is connected to an unillustrated ECU provided outside, and controls energization and stop of the primary winding 11 in accordance with an ignition signal IGt transmitted from the ECU.
The circuit module 20 includes a switching element such as a power MOSFET or IGBT, a driver for opening and closing the switching element, a control IC, and the like.
The ignition coil device 1 is controlled by the circuit module 20 and energizes and cuts off the primary coil wire 11, whereby the ratio N2 / N1 between the number of turns N1 of the primary coil 11 and the number of turns N2 of the secondary coil 12 is set. A proportional secondary voltage can be generated.
If necessary, a noise prevention capacitor, an auxiliary power supply capacitor, or the like may be incorporated.

A modification 1a of the ignition coil device according to the first embodiment will be described with reference to FIG.
In all of the following embodiments, the basic configuration is the same as that of the first embodiment, and the arrangement position, arrangement range, shape, etc. of the peeling members 50 and 51 which are the main parts of the present invention are the same. Different.
Therefore, in the following description, the description of the same configuration as that of the first embodiment will be omitted, and the description will focus on the different configuration.

In this modification 1a, the point which uses a sheet-like silicone tape etc. as the peeling members 50a and 51a is the same as that of the ignition coil apparatus 1 in 1st Embodiment.
In the modified example 1a, as shown on the left side of FIG. 2, the peeling member 50a is pasted so as to cover the side surface and the upper surface of the circuit module 20 at a position facing the inner peripheral side corner portion 313. As shown on the right side, the peeling member 51a is pasted so as to cover the bottom surface and the side surface of the central core 10 at a position facing the inner peripheral side corner 313.

By adopting such a configuration, even if there is a difference between the thermal expansion coefficient of the circuit module 20 and the thermal expansion coefficient of the insulating resin 40, a tensile stress acts on the insulating resin 40 in the portion where the peeling member 50a is interposed. As a result, stress concentration on the inner peripheral corner 313 is suppressed, and cracks can be prevented from occurring.
Similarly, between the central iron core 100 and the insulating resin 40, thermal stress is not concentrated on the inner peripheral side corner 313 by the peeling member 51a.

With reference to FIG. 3A and FIG. 3B, the ignition coil apparatus 1b in 2nd Embodiment and its modification 1c are demonstrated.
In 1st Embodiment, peeling member 50, 50a, 51, 51a is covered so that the inner peripheral side corner | angular part 313 of the circuit accommodating part 31 may be covered, or the range which opposes the inner peripheral side corner | angular part 313 may be covered. Although pasted, in this embodiment, the points which expanded the pasting range of peeling member 50b, 50c, 51b, 51c differ.

In the ignition coil device 1b according to the second embodiment, as shown on the left side of FIG. 3A, the peeling member 50b faces not only the inner side surface of the inner peripheral side corner portion 313 but also the side surface of the circuit module 20. It is pasted so as to cover the entire inner wall of the circuit housing part 31.
Further, as shown on the right side of FIG. 3A, the peeling member 51 b is pasted so as to cover not only the inner peripheral surface of the inner peripheral side corner portion 313 but also the entire inner wall of the circuit housing portion 31.

In the modified example 1c, as shown in FIG. 3B, the peeling member 50c is pasted so as to cover a wide range on the circuit module 20 side and the peeling member 51c is covered so as to cover a wide range on the central iron core 10 side.
Also in this embodiment, the same effect as the first embodiment can be exhibited.

With reference to FIG. 4A and FIG. 4B, the ignition coil apparatus 1d in the 3rd Embodiment of this invention and its modification 1e are demonstrated.
In this embodiment, the point which further expanded the adhesion range of peeling member 50d, 51d, 50e, 51e is different.

In the ignition coil device 1 d shown in FIG. 4A, the peeling members 50 d and 51 d are extended to a position facing the lead portion 21 on the inner peripheral surface of the housing 30.
By adopting such a configuration, in addition to the same effects as those of the above-described embodiment, relaxation of thermal stress on the lead portion 21 can be expected.
However, also in this embodiment, the peeling member 50d is not exposed from the surface of the insulating resin 40, and the opening of the housing 30 must be sealed with the insulating resin 40.

4B, the peeling member 50d is disposed so as to surround a part of the top surface, the side surface, and the bottom surface of the circuit module 20, and the peeling member 51d is disposed on the side surface, the bottom surface, and the side surface core 14 of the central core 10. It arrange | positions so that each one part of each side surface may be surrounded.
By adopting such a configuration, the same effects as those of the first embodiment are exhibited, and the occurrence of cracks due to stress concentration on the inner peripheral corner 313 can be suppressed.

With reference to FIG. 5A and FIG. 5B, the ignition coil apparatus 1f in the 4th Embodiment of this invention and its modification 1g are demonstrated.
In the said embodiment, although the example which affixes a sheet-like PET film as a peeling member was shown, in this embodiment, after resin-molding the housing 30 to the peeling members 50f, 50g, 51f, 51g, The formed point is different depending on the method of accommodating and installing in the housing 30 or applying to the inner peripheral surface of the housing 30.

Also in the present embodiment, the formation range of the peeling member can be appropriately changed as in the above-described embodiment.
In the present embodiment, the peeling members 50f and 50g are in contact with both the side surface of the circuit module 20 that is a thermal stress generation source and the inner peripheral surface of the circuit housing portion 31 that faces the circuit module 20, and a restraining force therebetween. Therefore, it is considered that the stress concentration on the inner peripheral side corner 313 can be avoided and the generation of cracks can be suppressed.
Furthermore, by using not only a hard material such as PET but also an elastic material such as silicone resin or fluorine resin as the peeling member, not only the stress due to peeling off from the insulating member 40 but also elastic deformation can be achieved. Therefore, it can be expected that one-phase stress relaxation will be achieved.

With reference to FIG. 7 and Tables 1 and 2, the results of thermal stress analysis by the finite element method for the principal stress distribution accompanying the thermal change of the circuit module 20 in the ignition coil device 1 according to the present invention will be described. To do.
As a basic model of the ignition coil device 1, the width W1 of the wide portion 301 is 28 mm, the width W2 of the narrow portion 311 is 14 mm, the width W3 of the circuit module 20 is 14 mm, and the height H1 of the wide portion 301 is 16 m. The height H2 of the narrow part 311 was 6 mm, and the height H3 of the circuit module 20 was 6 mm.
Further, assuming that the material constituting the housing 30 is PBT, the material constituting the filling resin 40 is epoxy resin, and the material constituting the circuit module 20 is equal to copper, the basic conditions are set, and the circuit module Thermal analysis using a finite element method was performed on the thermal stress when 20 had a temperature change from 0 ° C to 160 ° C.
As shown in FIG. 7, the main stress at this time is highest at the upper edge of the circuit module 20, and it is understood that the main stress acts on the inner corner 313 with respect to the circuit housing portion 31.

With reference to FIG. 8, the change of the maximum principal stress when the ratio of the lateral width W3 of the circuit module 20 to the lateral width W2 of the narrow portion 311 of the housing 30 is changed will be described.
As shown in FIG. 8, when the ratio W3 / W2 of the width W3 of the circuit module 20 to the width W2 of the narrow portion 311 increases, that is, as the distance between the side surface of the circuit module 20 and the narrow portion 311 decreases. When the ratio W3 / W2 of the width W3 of the circuit module 20 to the width W2 of the narrow portion 311 exceeds 63%, the fatigue stress of the material resin is exceeded, and the maximum value PSm (MPa) of the main stress increases. It has been found that there is a risk of cracks occurring at the side corners 313.

Here, referring to FIG. 9, when the ratio T2 / T1 of the width T2 of the peeling member 50 interposed between the inner peripheral side corner 313 and the circuit module 20 to the thickness T1 of the circuit module 20 is changed. The effect of will be described.
As shown in FIG. 9, even if the ratio W3 / W2 of the lateral width W3 of the circuit module 20 and the lateral width W2 of the narrow portion 311 is 63% or more, the maximum principal stress PSm can be reduced by interposing the peeling member 50. It turns out that it can be lowered.
In particular, by setting the width T2 of the peeling member 50 in the plate thickness direction of the circuit module 20 to a ratio T2 / T1 to the plate thickness T1 of the circuit module 20 of 60% or more, the circuit module 20 has a width W2 of the narrow portion 311. Even when the width W3 ratio W3 / W2 is close to 100%, that is, when the circuit module 20 and the narrow portion 311 are in close contact via the peeling member 50, the maximum principal stress PSm exceeds the fatigue limit of the material. Therefore, it is possible to reliably prevent the inner peripheral corner portion 313 from cracking.

With reference to FIG. 10, the maximum principal stress when the ratio W2 / W1 of the width W2 of the narrow portion 311 to the width W1 of the wide portion 301 of the housing 30 is changed will be described.
In FIG. 10, the peeling member 50 is not provided, and the housing 30 is obtained when the ratio W3 / W2 of the width W3 of the circuit module 20 to the width W2 of the narrow portion 311 is 100% and 50%. The change in the maximum principal stress PSm (MPa) was analyzed when the ratio W2 / W1 of the width W2 of the narrow portion 311 to the width W1 of the wide portion 301 was changed from 20% to 100%.
As a result, as shown in FIG. 10, it has been found that the change in the maximum principal stress PSm is small when the ratio W2 / W1 of the width W2 of the narrow portion 311 to the width W1 of the wide portion 301 of the housing 30 is changed. .

With reference to FIG. 11, the influence of the height H1 of the wide portion 301 and the height H2 of the narrow portion 311 will be described.
The ratio W3 / W3 of the lateral width W3 of the circuit module 20 to the lateral width W2 of the narrow portion 311 where the main stress PSm is the maximum without the separation member 50 being 100%, and the lateral width W1 of the wide portion 301 of the housing 30 The ratio W2 / W3 of the width W2 of the narrow part 311 is 25%, 50%, and 100%, and the ratio of the height H2 of the narrow part 311 to the height H1 of the wide part 301 is 50%, 100%, and 150%. , The change in the maximum principal stress PSm at 200% was analyzed.
As a result, as shown in FIG. 11, it has been found that the change in the maximum principal stress generated by the difference between the height H1 of the wide portion 301 and the height H2 of the narrow portion 311 is small.
From the above, in order to make it difficult for the inner peripheral side corner portion 313 to crack, when the lateral width W2 of the circuit module 20 with respect to the lateral width W1 of the narrow portion 311 is 63% or more and 100% or less, the inner periphery By interposing the peeling member 50 between the side corner portion 313 and the circuit module 20, the maximum principal stress PSm can be reduced below the fatigue limit of the material constituting the housing 30. Cracks can be prevented from occurring.
Furthermore, the ratio of the width W2 of the circuit module 20 to the width W1 of the narrow portion 311 is set so that the width T2 of the peeling member 50 in the thickness direction of the circuit module 20 is 60% or more with respect to the thickness T1 of the circuit module 20. Regardless of the above, it has been found that the maximum principal stress PSm can be made equal to or less than the fatigue limit of the material constituting the housing 30, and cracks can be prevented from occurring in the inner peripheral corner portion 313.

DESCRIPTION OF SYMBOLS 1 Ignition coil apparatus 100 Ignition coil 10 Central core 11 Primary coil 110 Primary winding 111 Primary bobbin 12 Secondary coil 120 Secondary winding 121 Secondary bobbin 122 Output relay terminal 123 High voltage terminal 124 Spring terminal 13 Permanent magnet 14 Side surface core 15 Core cover 20 Circuit module 21 Lead part 22 Connector terminal 30 Housing 301 Wide part 302 Connection part 31 Circuit accommodating part 311 Narrow part 313 Inner peripheral side corner 32 Connector 33 Plug cap 34 Flange 40 Insulating resin 50, 51 Peeling resin W1 Wide part width W2 Narrow part width W3 Circuit module width T1 Circuit module thickness T2 Width of peeling member in thickness direction of circuit module

Claims (6)

At least a primary coil (11), a secondary coil (12), a central iron core (10) arranged inside the primary coil (11), and a side iron core arranged outside the secondary coil (12) ( 14), and a circuit module (20) for controlling the supply and cut-off of the voltage to the coil (100) are accommodated inside the housing (30), and an insulating resin An ignition coil device sealed by (40),
A wide portion (301) formed in a lateral width (W1) in which the housing can accommodate the ignition coil with respect to a lateral width direction of the circuit module;
A narrow portion (311) formed in a lateral width (W2) narrower than the wide portion, constituting a circuit containing portion (31) for accommodating the circuit module;
A connecting portion (302) for connecting the wide portion and the narrow portion;
A peeling member (50, 50a to 50g) having a relatively weak adhesive force with the insulating resin is provided between the inner peripheral side corner (313) where the narrow portion and the connecting portion intersect with the circuit module. Ignition coil device (1, 1a to 1g) characterized by being inserted   The ignition coil device (1, 1a to 1g) according to claim 1, wherein a ratio (W3 / W2) of a width (W3) of the circuit module to a width (W2) of the narrow portion is 63% or more and 100% or less. )   The ignition coil device (1, 1a to 1g) according to claim 1 or 2, wherein a ratio (T2 / T1) of a width (T2) of the peeling member to a thickness (T1) of the circuit module is 60% or more.   The ignition coil device (1) according to any one of claims 1 to 3, wherein the peeling member is provided at a position covering at least the inner peripheral side corner or a position covering the circuit module in a range facing the peeling member. 1a-1g)   A second peeling member (51, 51a, 51b, 51c, 51d, 51e, which has a relatively low adhesive force to the insulating resin between the central iron core and / or the side iron core and the circuit housing portion, The ignition coil device (1, 1a to 1g) according to any one of claims 1 to 4, wherein 51f, 51g) are interposed.   2. The insulating resin is made of a resin material selected from either an epoxy resin or a urethane resin, and the release member is made of a resin material selected from any of silicone, polypropylene, polyamide, polyimide, nylon, and fluororesin. To the ignition coil device (1, 1a to 1g)

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