JP2020188040A - Ignition coil and manufacturing method of the same - Google Patents

Abstract

To provide an ignition coil capable of suppressing leakage of liquid resin and enlargement of an ignition coil without providing a cover member.SOLUTION: An ignition coil (10) includes a case (50) containing a primary coil (20) and a secondary coil (30), and a resin (80) filled inside the case. The case has a bottomed tubular shape having an opening (51) formed at an end (59) in a predetermined direction. A distance from a predetermined end (51a) of the opening to a surface (80a) of the resin in the predetermined direction is a first distance. In the case, in a part of a second distance shorter than the first distance from an end of the opening in the predetermined direction, a thin wall portion (60) is formed along a circumferential direction of the opening.SELECTED DRAWING: Figure 1

Description

The present invention relates to an ignition coil in which a resin is filled inside the case.

Conventionally, there is an ignition coil which is provided with a case having an opening opened on the upper side, and is manufactured by pouring a liquid resin from the opening into the case and then curing the resin in a heating step (see Patent Document 1). .. In the ignition coil described in Patent Document 1, an annular cover member having an annular cover member that projects from the inner circumference of the opening toward the inside of the case and penetrates in the vertical direction inside the opening is provided at the opening. There is. As a result, the exposed area of the liquid surface in the liquid resin before curing can be reduced, the wave height when the liquid surface undulates due to an external force such as vibration can be reduced, and the leakage of the resin can be suppressed. ..

Japanese Unexamined Patent Publication No. 2016-58491

By the way, in the ignition coil described in Patent Document 1, it is necessary to provide the cover member in the case of the ignition coil.

Further, it is conceivable to raise the height of the case with respect to the liquid level of the resin in order to prevent the liquid resin from leaking, but this is not preferable because the ignition coil becomes large.

The present invention has been made to solve the above problems, and a main object thereof is to provide an ignition coil capable of suppressing leakage of liquid resin and enlargement of the ignition coil without providing a cover member. To provide.

The first means for solving the above problems is
An ignition coil (10) including a case (50) containing a primary coil (20) and a secondary coil (30) and a resin (80) filled inside the case.
The case has a bottomed tubular shape having an opening (51) formed at an end (59) in a predetermined direction.
The distance from the end (51a) of the opening in the predetermined direction to the surface (80a) of the resin in the predetermined direction is the first distance (h1).
In the case, the portion of the second distance (h2, h21 to h24) shorter than the first distance from the end of the opening in the predetermined direction is a thin portion (60, 60a) along the circumferential direction of the opening. ~ 60d, 260) are formed.

According to the above configuration, the ignition coil includes a case containing the primary coil and the secondary coil, and a resin filled inside the case. The resin is poured into the case in a liquid state (liquid) and cured by a heating process or the like.

Here, the case has a bottomed tubular shape having an opening formed at an end portion in a predetermined direction. Therefore, a liquid resin can be poured into the inside of the case through the opening and stored. The distance from the end of the opening in the predetermined direction to the surface of the resin in the predetermined direction is the first distance. The case can also be designed so that when a required predetermined amount of liquid resin is poured, the distance from the liquid surface to the end of the opening in a predetermined direction becomes long. In that case, even if the ignition coil is tilted or an external force such as vibration is applied to the ignition coil when the ignition coil is moved to a heating process or the like, it is possible to prevent the liquid resin from leaking from the opening. .. However, designing the case in this way is not preferable because the first distance becomes long and the ignition coil becomes large.

In this respect, in the case, a thin portion is formed along the circumferential direction of the opening in the portion of the second distance shorter than the first distance from the end in the predetermined direction of the opening. In the case, the strength of the portion where the thin-walled portion is formed is lower than the strength of the portion where the thin-walled portion is not formed. Therefore, even if the first distance is increased in order to suppress the leakage of the liquid resin, the end portion in the predetermined direction (hereinafter referred to as “predetermined end portion”) in which the opening is formed in the case is along the thin-walled portion. Can be divided. As a result, leakage of the liquid resin and increase in size of the ignition coil can be suppressed without providing the cover member.

The second means is
An ignition coil (10) including a case (50) containing a primary coil (20) and a secondary coil (30), and the inside of the case is filled with resin (80).
The case has a bottomed tubular shape having an opening (51) formed at an end (59) in a predetermined direction.
In the case, the portion of the second distance (h2, h21 to h24) from the end (51a) of the opening in the predetermined direction is a thin portion (60, 60a to 60d, 260) along the circumferential direction of the opening. ) Is formed.

According to the above configuration, when a predetermined amount of liquid resin required is poured from the opening into the case as in the first means, the distance from the liquid surface to the end of the opening in the predetermined direction becomes long. You can also design the case. In that case, the first distance becomes long and the ignition coil becomes large, which is not preferable. In this respect, in the case, a thin-walled portion is formed along the circumferential direction of the opening in the portion of the second distance from the end in the predetermined direction of the opening. Thereby, the same action and effect as the first means can be obtained.

In the third means, the thin-walled portion is continuously formed over the entire circumference in the circumferential direction of the opening. According to such a configuration, it is possible to suppress the bias of the strength of the predetermined end portion in the case as compared with the configuration in which the thin-walled portions are formed at regular intervals in the circumferential direction of the opening. Therefore, it becomes easy to divide the predetermined end portion along the thin wall portion. Further, the shape of the thin-walled portion can be simplified, and the case can be easily formed by resin molding or the like.

In the fourth means, the thin-walled portion is formed by forming a groove on the outer peripheral edge portion of the case. According to such a configuration, it becomes easier to visually confirm the position of the thin-walled portion, which is the position for dividing the case, as compared with the configuration in which the thin-walled portion is formed by forming a groove on the inner peripheral edge of the case. , The work of dividing the case becomes easy.

In the fifth means, the case is a bottomed square cylinder having the opening formed at the end in the predetermined direction, and in the case, the four corners (58) of the end in the predetermined direction. A first vertical groove (64) extending from the end of the opening in the predetermined direction to the portion of the second distance is formed on the inner edge portion.

According to the above configuration, the case is a bottomed square cylinder having an opening formed at an end portion in a predetermined direction. Therefore, the case has four faces and four corners (corners). Then, in the case, first vertical grooves extending from the end of the opening in the predetermined direction to the portion of the second distance are formed at the inner edges of the four corners of the ends in the predetermined direction. Therefore, when the predetermined end portion of the case is divided along the thin-walled portion, the predetermined end portion can be divided for each surface of the case by dividing the predetermined end portion at the portion of the first vertical groove. Therefore, the predetermined end of the case can be easily divided.

In the sixth means, the case has a bottomed square tube shape having the opening formed at the end portion in the predetermined direction, and in the case, the four corner portions (58) of the end portion in the predetermined direction. A second vertical groove (68) extending from the end of the opening in the predetermined direction to the portion of the second distance is formed on the outer edge portion. According to such a configuration, when the predetermined end portion of the case is divided along the thin wall portion, the predetermined end portion can be divided for each surface of the case by dividing the predetermined end portion at the portion of the second vertical groove. Therefore, the predetermined end of the case can be easily divided.

The seventh means is a method for manufacturing the ignition coil (10).
A bottomed tubular case (50) having an opening (51) formed at an end (59) in a predetermined direction, at a second distance (h2, h21 to h24) from the end of the opening in the predetermined direction. The case was created in which a thin portion (60, 60a to 60d, 260) was formed in the portion along the circumferential direction of the opening.
The primary coil (20) and the secondary coil (30) are housed inside the case.
A predetermined amount of liquid resin is poured from the opening into the case,
The first distance is longer than the second distance by curing the liquid resin so that the distance from the end (51a) of the opening in the predetermined direction to the surface (80a) of the resin (80) in the predetermined direction is longer than the second distance. (H1)
After the liquid resin is cured, the end portion in the predetermined direction in which the opening is formed in the case is divided along the thin wall portion.

According to the above step, it is a bottomed tubular case in which an opening is formed at an end in a predetermined direction, and a thin portion is formed at a portion of a second distance from the end in the predetermined direction of the opening along the circumferential direction of the opening. The case in which is formed is created. The primary coil and the secondary coil are housed inside the case, and a predetermined amount of liquid resin is poured from the opening into the inside of the case.

Here, if the distance from the liquid surface to the end of the opening in the predetermined direction is long, the ignition coil may be tilted or an external force such as vibration may be applied to the ignition coil before the liquid resin inside the case is cured. However, it is possible to prevent the liquid resin from leaking from the opening. However, if the case is designed so that the distance from the liquid surface to the end of the opening in the predetermined direction becomes long, the first distance becomes long and the ignition coil becomes large, which is not preferable.

At this point, a thin portion is formed along the circumferential direction of the opening at the portion of the second distance shorter than the first distance from the end in the predetermined direction of the opening. Therefore, after the liquid resin is cured, the end portion (predetermined end portion) in the predetermined direction in which the opening is formed in the case can be divided along the thin-walled portion. Therefore, even if the cover member is not provided, the leakage of the liquid resin and the increase in size of the ignition coil can be suppressed.

Sectional view of the ignition coil. Partial perspective view of the ignition coil. Partial cross-sectional view of the case and resin. Partial plan view of the case and resin. The schematic diagram which shows the cutting mode of the upper end part. The schematic diagram which shows the cutting mode of the upper end part. The schematic diagram which shows the division mode of the upper end part. Partial sectional view which shows the modification example of the thin-walled part of a case. Partial sectional view showing another modification example of the thin part of a case. Partial sectional view showing another modification example of the thin part of a case. Partial sectional view showing another modification example of the thin part of a case. Partial sectional view showing another modification example of the thin part of a case.

Hereinafter, an embodiment embodied in the ignition coil used in the internal combustion engine will be described with reference to the drawings.

As shown in FIG. 1, the ignition coil 10 is formed by winding a primary coil 20 formed by winding a primary winding and by winding a secondary winding arranged on the outer periphery of the primary coil 20. It includes a secondary coil 30. The ignition coil 10 includes a central core 40 inserted inside the primary coil 20 and the secondary coil 30, and an outer peripheral core 45 arranged on the outer periphery of the primary coil 20 and the secondary coil 30. The primary coil 20, the secondary coil 30, the central core 40, and the outer peripheral core 45 are housed inside the case 50. The inside of the case 50 is filled with a resin 80 having electrical insulation.

The case 50 is formed in a bottomed square cylinder shape (bottomed cylinder shape). An opening 51 is formed at the end portion 59 of the case 50 in the upward direction (predetermined direction). That is, the case 50 has a bottomed square cylinder shape (bottomed cylinder shape) in which an opening 51 is formed in a predetermined direction. The case 50 has a side wall portion 52 that surrounds the primary coil 20, the secondary coil 30, the central core 40, and the outer peripheral core 45 and forms an opening 51, and a lower side (opposite to a predetermined direction) of the side wall portion 52. It has a bottom 53 that closes the side). In the following description, in the case 50, the direction from the center (center of gravity) to the opening 51 is upward, and the direction from the center to the bottom 53 is downward.

The ignition coil 10 is used in an internal combustion engine such as an automobile to apply a high voltage to an ignition plug disposed in a combustion chamber with exposed electrodes. In the ignition coil 10, a high voltage is induced in the secondary coil 30 as the current in the primary coil 20 changes.

The primary coil 20 of the ignition coil 10 is formed by winding the primary winding around the outer circumference of the primary spool 25. The primary spool 25 is formed in a cylindrical shape by an insulating resin. A cylindrical primary coil 20 is formed by winding the primary winding around the primary spool 25.

The secondary coil 30 is formed by winding a secondary winding around a secondary spool 35. The secondary spool 35 is arranged coaxially with the primary spool 25 and on the outer circumference of the primary spool 25. The secondary spool 35 has a cylindrical main body portion 36 and a plurality of flange portions 37 erected from the outer peripheral surface of the main body portion 36 toward the outer peripheral side. The plurality of flange portions 37 are arranged side by side in the axial direction of the main body portion 36. The secondary coil 30 is formed by winding a secondary winding between adjacent flanges 37.

A central core 40 is provided inside the primary spool 25. The central core 40 is formed in a square columnar shape by laminating a plurality of magnetic steel plates in the vertical direction. The longitudinal direction of the central core 40 coincides with the axial direction of the primary spool 25.

An outer peripheral core 45 is provided on the outer circumference of the secondary spool 35. The outer peripheral core 45 has a laminated body in which a plurality of magnetic steel plates are laminated, and a coating layer made of an insulating resin that covers the outer periphery of the laminated body. The outer peripheral core 45 is formed in a square cylinder shape that penetrates in the vertical direction. Inside the outer peripheral core 45, a primary coil 20, a secondary coil 30, and a central core 40 are arranged. The outer peripheral core 45 surrounds these in the left-right direction (the above-mentioned axial direction) and the depth direction (the direction perpendicular to the paper surface), that is, the sides. A magnet 72 is provided between one side portion of the outer peripheral core 45 and one end of the central core 40 to generate a magnetic flux in the direction opposite to the magnetic flux generated in the primary coil 20 in the magnetic path.

A connector 55 is formed on the side wall portion 52 of the case 50 along the axial direction of the central core 40. Inside the connector 55, a connection terminal 73 electrically connected to the igniter 70 is arranged.

The bottom portion 53 is formed with a tubular protruding portion 57 that projects downward. A high-voltage terminal 76 electrically connected to the secondary coil 30 is inserted inside the protrusion 57 via a high-voltage connection terminal 74. A joint (not shown) is assembled to the protrusion 57.

As shown in FIGS. 2 and 3, the inside of the case 50 is filled with the resin 80 from the bottom portion 53 to the vicinity of the end portion 59. The resin 80 is poured in a liquid state through the opening 51 and then heated and cured. The distance from the upward end 51a of the opening 51 to the upward surface 80a of the resin 80 is the first distance h1. The first distance h1 is the distance from the end 51a to the surface 80a after the liquid resin impregnates the gap in the case 50 and further shrinks by heating. The first distance h1 is the distance from the end 51a to the lowest portion of the surface 80a.

In the case 50, an annular thin-walled portion 60 is formed along the circumferential direction of the opening 51 at a portion of the second distance h2 shorter than the first distance h1 from the upper end 51a of the opening 51. The thin-walled portion 60 is a portion whose wall thickness (thickness) is thinner than the periphery thereof. The thin-walled portion 60 is formed by forming a groove 62 in a portion closer to the outer surface of the side wall portion 52 of the case 50, that is, in the outer peripheral edge portion of the case 50. The groove 62 is continuously formed in the case 50 in the circumferential direction of the opening 51 over the entire circumference. As a result, the thin portion 60 is continuously formed in the case 50 in the circumferential direction of the opening 51 over the entire circumference. The cross-sectional shape of the groove 62 is trapezoidal. In the vertical direction, the distance from the end 51a to the center of the thinnest portion of the thin portion 60 is defined as the second distance h2.

As shown in FIGS. 2 and 4, in the case 50, the inner edge portion of the four corner portions 58 of the upward end portion 59 has a first portion extending from the upward end 51a of the opening 51 to the portion of the second distance h2. The vertical grooves 64 are formed respectively. That is, the first vertical groove 64 extends from the upward end 51a of the opening 51 to the thinnest portion of the thin portion 60 at the inner edge portion of the corner portion 58. The cross-sectional shape of the first vertical groove 64 is triangular (V-shaped).

In the case 50, a second vertical groove 68 extending from the upper end 51a of the opening 51 to a portion of the second distance h2 is formed at the outer edge of the four corners 58 of the upper end 59, respectively. .. That is, the second vertical groove 68 extends from the upward end 51a of the opening 51 to the thinnest portion of the thin portion 60 at the outer edge portion of the corner portion 58. The cross-sectional shape of the second vertical groove 68 is trapezoidal (rectangular).

In the circumferential direction of the opening 51, the position of the first vertical groove 64 and the position of the second vertical groove 68 coincide with each other. That is, the first vertical groove 64 and the second vertical groove 68 face each other.

Next, a manufacturing method (production method) of the ignition coil 10 will be described.

First, the case 50 is created by integrally molding an insulating resin using a mold or the like. Specifically, it is a bottomed square tubular case 50 in which an opening 51 is formed in an upward 51a portion, and is a portion of the opening 51 at a second distance h2 from the upward 51a along the circumferential direction of the opening 51. The case 50 in which the annular thin-walled portion 60 is formed is created.

Subsequently, the parts of the ignition coil 10 such as the primary coil 20, the secondary coil 30, the central core 40, the outer peripheral core 45, and the igniter 70 are housed inside the case 50. Then, the stored parts are fixed to the case 50.

Subsequently, in a vacuum environment, a predetermined amount of thermosetting and electrically insulating liquid resin (resin before thermosetting) is poured from the opening 51 into the case 50. The predetermined amount is an amount that the thermosetting resin 80 can cover and protect the primary coil 20, the secondary coil 30, the central core 40, the outer peripheral core 45, the igniter 70, and the like. The liquid resin poured into the case 50 is impregnated into the gap inside the case 50. At this time, the liquid level of the liquid resin is slightly higher than the surface 80a of the resin 80 after heat curing. The distance from the liquid surface of the liquid resin to the upward end 51a of the opening 51 may cause the ignition coil 10 to tilt or an external force such as vibration to be applied to the ignition coil 10 when the ignition coil 10 is moved to the heating process. Even so, the distance is such that the liquid resin can be prevented from leaking from the opening 51. That is, the case 50 is designed so that the distance from the liquid surface of the liquid resin to the upward end 51a of the opening 51 is a distance at which the liquid resin does not leak.

However, if the case 50 is designed so that the distance from the liquid surface of the liquid resin to the upward end 51a of the opening 51 is long, the first distance h1 after thermosetting the resin is long, and the ignition coil 10 is large. It is not preferable because it becomes In this regard, the following steps suppress the leakage of the liquid resin and the increase in size of the ignition coil 10.

Subsequently, the ignition coil 10 is placed on a conveyor (moving device) and moved to the heating step. Specifically, a plurality of ignition coils 10 are placed on a pallet (loading platform), and the pallets are placed on a conveyor. The conveyor moves the pallets horizontally to the heating process. At this time, the pallet (ignition coil 10) may be tilted or vibration may be applied to the pallet, causing the liquid level to shake. In particular, an ignition coil having a plurality of primary coils and capable of additional energy input tends to be large in size and has a wide opening area. In such a large ignition coil 10, the height difference generated when the ignition coil 10 is tilted becomes large, and the exposed area of the liquid surface in the liquid resin is large, so that the liquid resin easily leaks from the opening 51. However, since the case 50 is designed so that the distance from the liquid surface of the liquid resin to the upward end 51a of the opening 51 becomes long, it is possible to prevent the liquid resin from leaking from the opening 51. , Especially has a physique suppression effect on large coils.

Subsequently, in the heating step, the ignition coil 10 is made substantially horizontal, and the liquid resin is heated and cured by the heating device. The liquid resin shrinks slightly when heated. Further, in the process of heating and curing, the viscosity of the liquid resin decreases, and the invasion of the primary coil 20, the secondary coil 30, the central core 40, the outer peripheral core 45, and the like into the gaps is promoted. The surface 80a of the resin 80 after curing is lowered. Then, the distance from the upward end 51a of the opening 51 to the upward surface 80a of the resin 80 becomes the first distance h1 which is longer than the second distance h2.

Subsequently, as shown in FIG. 5, the ignition coil 10 is fixed by the jig J. At this time, the ignition coil 10 is fixed so that the blade E of the cutting device hits the groove 62 (thin wall portion 60). Then, as shown in FIGS. 5 and 6, the blade E of the cutting device cuts (divides) the upward end portion 59 in which the opening 51 is formed in the case 50 along the groove 62. At this time, since the surface 80a of the resin 80 is located lower than the thin portion 60 inside the case 50, the resin 80 is not cut.

The present embodiment described in detail above has the following advantages.

In the case 50, a thin portion 60 is formed along the circumferential direction of the opening 51 at a portion of the second distance h2 shorter than the first distance h1 from the upper end 51a of the opening 51. In the case 50, the strength of the portion where the thin-walled portion 60 is formed is lower than the strength of the portion where the thin-walled portion 60 is not formed. Therefore, even if the first distance h1 is lengthened in order to suppress the leakage of the liquid resin, the upward end portion 59 in which the opening 51 is formed in the case 50 can be cut along the thin-walled portion 60. .. As a result, it is possible to suppress the leakage of the liquid resin and the increase in size of the ignition coil 10 without providing the cover member.

The thin portion 60 is continuously formed over the entire circumference in the circumferential direction of the opening 51. According to such a configuration, it is possible to suppress the bias of the strength of the end portion 59 in the case 50 as compared with the configuration in which the thin-walled portions 60 are formed at regular intervals in the circumferential direction of the opening 51. Therefore, it becomes easy to cut the end portion 59 along the thin portion 60. Further, the shape of the thin portion 60 can be simplified, and the case 50 can be easily formed by resin molding.

The thin-walled portion 60 is formed by forming a groove 62 on the outer peripheral edge portion of the case 50. According to such a configuration, the groove 62 (that is, the thin-walled portion 60) at which the case 50 is cut is compared with the configuration in which the thin-walled portion 60 is formed by forming the groove 62 on the inner peripheral edge portion of the case 50. ) Can be visually confirmed, and the work of cutting the case 50 becomes easy.

It should be noted that the above embodiment can be modified and implemented as follows. The same parts as those in the above embodiment are designated by the same reference numerals, and the description thereof will be omitted.

-As shown in FIG. 7, the end portion 59 of the case 50 may be divided by using pliers P, nippers, or the like.

The case 50 has a bottomed square cylinder with an opening 51 formed at an upward end 59. Therefore, the case 50 has four side wall portions 52 (faces) and four corner portions 58 (corner portions). Then, in the case 50, first vertical grooves 64 extending from the upward end 51a of the opening 51 to the portion of the second distance h2 are formed at the inner edges of the four corners 58 of the upward end 59. Has been done. Therefore, when the end portion 59 of the case 50 is divided along the thin-walled portion 60 by a pliers P, nippers, or the like, the end portion is divided by the portion of the first vertical groove 64, so that the end portion of each surface of the case 50 59 can be divided. Therefore, the end portion 59 of the case 50 can be easily divided.

In the case 50, second vertical grooves 68 extending from the upper end 51a of the opening 51 to the portion of the second distance h2 are formed at the outer edges of the four corners 58 of the upper end 59, respectively. There is. According to such a configuration, when the end portion 59 of the case 50 is divided along the thin-walled portion 60 by a pliers P, nippers, or the like, the first vertical groove 64 and the second vertical groove 68 are divided. The end portion 59 can be divided for each surface of the case 50. Therefore, the end portion 59 of the case 50 can be more easily divided.

As shown in FIG. 8, the thin portion 60 may be formed by forming a groove 162 having a right-angled trapezoidal cross section on the outer peripheral edge portion of the case 50. The groove 162 is continuously formed in the case 50 in the circumferential direction of the opening 51 over the entire circumference. As a result, the thin portion 60 is continuously formed in the case 50 in the circumferential direction of the opening 51 over the entire circumference. Further, as shown in FIG. 9, the cross-sectional shape of the groove 162 can be changed. The cross-sectional shape of the grooves 62 and 162 is not limited to a trapezoidal shape, and may be arbitrary such as a rectangular shape, a triangular shape, and a semicircular shape.

As shown in FIG. 10, a plurality of thin-walled portions 60a to 60d can be formed on the end portion 59 of the case 50. The thin-walled portions 60a to 60d are formed by forming grooves 62A to 62D, respectively, on the outer peripheral edge portion of the case 50. In the thin portions 60a to 60d, the second distances h21 to h24 are different from each other. According to such a configuration, the dimension of the case 50 in the height direction can be changed by changing the position where the end portion 59 is cut (divided).

As shown in FIG. 11, instead of the grooves 62 and 162, a plurality of recesses 262 may be formed at the end 59 of the case 50 along the circumferential direction of the opening 51. The thin-walled portion 260 is formed by forming recesses 262 on the outer peripheral edge of the case 50, respectively. With such a configuration, the upward end portion 59 in which the opening 51 is formed in the case 50 can be cut along the plurality of thin-walled portions 260. As shown in FIG. 12, the number of recesses 262 can also be changed. The cross-sectional shape of the recess 262 is not limited to a trapezoidal shape, but may be arbitrary, such as a rectangular shape, a triangular shape, or a semicircular shape.

A first vertical groove 64 and a second vertical groove 68 may be formed only in the two diagonal portions 58. Further, the first vertical groove 64 can be omitted. Further, the second vertical groove 68 can be omitted.

-The case 50 can also be formed into a bottomed hexagonal cylinder or a bottomed cylinder.

By forming grooves 62, 162, 62A to 62D and recesses 262 on the inner peripheral edge of the case 50, thin-walled portions 60 and 260 can also be formed.

-The resin 80 is not limited to a thermosetting resin, and may be any material such as an ultraviolet curable resin that is cured after being poured into the case 50 in a liquid state.

10 ... Ignition coil, 20 ... Primary coil, 30 ... Secondary coil, 50 ... Case, 51 ... Opening, 51a ... End, 59 ... End, 60 ... Thin-walled part, 60a ... Thin-walled part, 60b ... Thin-walled part, 60c ... Thin-walled part, 60d ... Thin-walled part, 80 ... Resin, 80a ... Surface, 260 ... Thin-walled part.

Claims (7)

An ignition coil (10) including a case (50) containing a primary coil (20) and a secondary coil (30) and a resin (80) filled inside the case.
The case has a bottomed tubular shape having an opening (51) formed at an end (59) in a predetermined direction.
The distance from the end (51a) of the opening in the predetermined direction to the surface (80a) of the resin in the predetermined direction is the first distance (h1).
In the case, the portion of the second distance (h2, h21 to h24) shorter than the first distance from the end of the opening in the predetermined direction is a thin portion (60, 60a) along the circumferential direction of the opening. An ignition coil in which ~ 60d, 260) is formed. An ignition coil (10) including a case (50) containing a primary coil (20) and a secondary coil (30), and the inside of the case is filled with resin (80).
The case has a bottomed tubular shape having an opening (51) formed at an end (59) in a predetermined direction.
In the case, the portion of the second distance (h2, h21 to h24) from the end (51a) of the opening in the predetermined direction is a thin portion (60, 60a to 60d, 260) along the circumferential direction of the opening. ) Is formed, the ignition coil. The ignition coil according to claim 1 or 2, wherein the thin portion (60, 60a to 60d) is continuously formed over the entire circumference in the circumferential direction of the opening. The ignition coil according to claim 3, wherein the thin portion (60, 60a to 60d) is formed by forming a groove on the outer peripheral edge portion of the case. The case has a bottomed square tube shape having the opening formed at the end in the predetermined direction.
In the case, a first flute (64) extending from the end of the opening in the predetermined direction to the second distance portion is formed at the inner edge of the four corners (58) of the end in the predetermined direction. The ignition coil according to any one of claims 1 to 4, which is formed. The case has a bottomed square tube shape having the opening formed at the end in the predetermined direction.
In the case, a second vertical groove (68) extending from the end of the opening in the predetermined direction to the portion of the second distance is formed on the outer edge of the four corners (58) of the end in the predetermined direction. The ignition coil according to any one of claims 1 to 5, which is formed. A bottomed tubular case (50) having an opening (51) formed at an end (59) in a predetermined direction, at a second distance (h2, h21 to h24) from the end of the opening in the predetermined direction. The case was created in which a thin portion (60, 60a to 60d, 260) was formed in the portion along the circumferential direction of the opening.
The primary coil (20) and the secondary coil (30) are housed inside the case.
A predetermined amount of liquid resin is poured from the opening into the case,
By curing the liquid resin, the distance from the end (51a) of the opening in the predetermined direction to the surface (80a) of the resin (80) in the predetermined direction is a first distance longer than the second distance. (H1)
A method for producing an ignition coil (10), wherein after curing the liquid resin, the end portion in the predetermined direction in which the opening is formed in the case is divided along the thin wall portion.

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