JP7434723B2 - ignition coil - Google Patents

Description

The present invention relates to an ignition coil whose case is filled with resin.

Conventionally, there is an ignition coil that includes a case having an opening that opens upward, and that is manufactured by pouring liquid resin into the case through the opening and then hardening the resin in a heating process (see Patent Document 1). . In the ignition coil described in Patent Document 1, the opening is provided with an annular cover member that protrudes from the inner periphery of the opening toward the inside of the case and has a through hole that penetrates inside the opening in the vertical direction. There is. This reduces the exposed area of the liquid surface of the liquid resin before hardening, reduces the wave height when the liquid surface ripples due to external forces such as vibrations, and suppresses resin leakage. .

Japanese Patent Application 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.

Furthermore, in order to prevent the liquid resin from leaking, it is conceivable to make the height of the case higher than the liquid level of the resin, but this is not preferable because it increases the size of the ignition coil.

The present invention has been made to solve the above problems, and its main purpose is to provide an ignition coil that can suppress leakage of liquid resin and increase in size of the ignition coil without providing a cover member. It is about providing.

The first means to solve the above problem is
An ignition coil (10) comprising a case (50) housing a primary coil (20) and a secondary coil (30), and a resin (80) filled inside the case,
The case has a bottomed cylindrical shape with 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 a first distance (h1),
In the case, a thin wall portion (60, 60a) is provided along the circumferential direction of the opening at a second distance (h2, h21 to h24) shorter than the first distance from the end of the opening in the predetermined direction. ~60d, 260) are formed.

According to the above configuration, the ignition coil includes a case housing 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 state), and is hardened by a heating process or the like.

Here, the case has a bottomed cylindrical shape with an opening formed at an end in a predetermined direction. Therefore, liquid resin can be poured into the case through the opening and stored therein. The distance from the end of the opening in the predetermined direction to the surface of the resin in the predetermined direction is a 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 level to the end of the opening in a predetermined direction becomes longer. In that case, even if the ignition coil is tilted or an external force such as vibration is applied to the ignition coil when moving the ignition coil to a heating process etc., leakage of liquid resin from the opening can be suppressed. . However, if the case is designed in this way, the first distance becomes longer and the ignition coil becomes larger, which is not preferable.

In this regard, in the case, a thin wall portion is formed along the circumferential direction of the opening at a second distance shorter than the first distance from the end of the opening in the predetermined direction. In the case, the strength of the portion where the thin wall portion is formed is lower than the strength of the portion where the thin wall portion is not formed. For this reason, even if the first distance is increased in order to suppress leakage of liquid resin, the edge of the case in the predetermined direction where the opening is formed (hereinafter referred to as the "predetermined end") can be moved along the thin wall part. Can be divided. As a result, leakage of liquid resin and enlargement of the ignition coil can be suppressed without providing a cover member.

The second means is
An ignition coil (10) comprising a case (50) housing a primary coil (20) and a secondary coil (30), the inside of the case being filled with a resin (80),
The case has a bottomed cylindrical shape with an opening (51) formed at an end (59) in a predetermined direction,
In the case, a thin wall portion (60, 60a to 60d, 260 ) is formed.

According to the above configuration, similarly to the first means, when a necessary predetermined amount of liquid resin is poured into the inside of the case from the opening, the distance from the liquid level to the end of the opening in the predetermined direction becomes longer. You can also design a case. In that case, the first distance becomes longer and the ignition coil becomes larger, which is not preferable. In this regard, in the case, a thin wall portion is formed along the circumferential direction of the opening at a second distance from the end of the opening in the predetermined direction. Thereby, the same effect as the first means can be achieved.

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

In a fourth means, the thin wall portion is formed by forming a groove in the outer peripheral edge of the case. According to this configuration, compared to a configuration in which the thin wall portion is formed by forming a groove on the inner peripheral edge of the case, it is easier to visually confirm the position of the thin wall portion where the case is divided. , the work of dividing the case becomes easier.

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

According to the above configuration, the case has a bottomed rectangular cylindrical shape with an opening formed at an end in a predetermined direction. Therefore, the case has four sides and four corners. In the case, first vertical grooves extending from the end of the opening in the predetermined direction to the second distance are formed in the inner edges of the four corners of the end in the predetermined direction, respectively. Therefore, when dividing the predetermined end portion of the case along the thin wall portion, by dividing the predetermined end portion at the first longitudinal groove, the predetermined end portion can be separated for each side of the case. Therefore, the predetermined end of the case can be easily separated.

In a sixth means, the case has a bottomed square cylindrical shape with the opening formed at the end in the predetermined direction, and in the case, four corners (58) of the end in the predetermined direction are formed. A second vertical groove (68) is formed in each outer edge portion, and extends from the end of the opening in the predetermined direction to a portion of the second distance. According to this 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 side of the case by dividing the predetermined end portion along the second longitudinal groove. Therefore, the predetermined end of the case can be easily separated.

A seventh means is a method for manufacturing an ignition coil (10), comprising:
A bottomed cylindrical case (50) having an opening (51) formed at an end (59) in a predetermined direction, the case (50) having a second distance (h2, h21 to h24) from the end of the opening in the predetermined direction. Creating the case in which a thin wall portion (60, 60a to 60d, 260) is formed along the circumferential direction of the opening,
A primary coil (20) and a secondary coil (30) are stored inside the case,
pouring a predetermined amount of liquid resin into the inside of the case from the opening;
The liquid resin is cured, and 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 set to a first distance that is longer than the second distance. (h1),
After the liquid resin is cured, the end portion of the case in the predetermined direction where the opening is formed is divided along the thin wall portion.

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

If the distance from the liquid level to the end of the opening in the specified direction is long, the ignition coil may be tilted or external force such as vibration may be applied to the ignition coil before the liquid resin inside the case hardens. Also, leakage of liquid resin from the opening can be suppressed. However, if the case is designed so that the distance from the liquid level to the end of the opening in the predetermined direction is long, the first distance becomes long and the ignition coil becomes large, which is not preferable.

In this regard, a thin wall portion is formed along the circumferential direction of the opening at a portion of the second distance shorter than the first distance from the end of the opening in the predetermined direction. 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 wall portion. Therefore, even without providing a cover member, leakage of liquid resin and enlargement of the ignition coil can be suppressed.

A cross-sectional view of an ignition coil. A partial perspective view of an ignition coil. A partial sectional view of a case and resin. A partial plan view of a case and resin. FIG. 3 is a schematic diagram showing how the upper end portion is cut. FIG. 3 is a schematic diagram showing how the upper end portion is cut. FIG. 3 is a schematic diagram showing how the upper end portion is divided. FIG. 6 is a partial cross-sectional view showing an example of a change in the thin wall portion of the case. FIG. 7 is a partial cross-sectional view showing another example of a modification of the thin wall portion of the case. FIG. 7 is a partial cross-sectional view showing another example of a modification of the thin wall portion of the case. FIG. 7 is a partial cross-sectional view showing another example of a modification of the thin wall portion of the case. FIG. 7 is a partial cross-sectional view showing another example of a modification of the thin wall portion of the case.

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

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

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

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

The primary coil 20 of the ignition coil 10 is formed by winding a primary winding around the outer periphery of a primary spool 25. The primary spool 25 is made of insulating resin and has a cylindrical shape. By winding the primary winding around the primary spool 25, a cylindrical primary coil 20 is formed.

The secondary coil 30 is formed by winding a secondary winding around a secondary spool 35. The secondary spool 35 is disposed coaxially with the primary spool 25 and on the outer periphery of the primary spool 25. The secondary spool 35 has a cylindrical main body 36 and a plurality of flanges 37 that stand upright from the outer circumferential surface of the main body 36 toward the outer circumferential side. The plurality of collar 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 into a rectangular column shape by vertically stacking a plurality of magnetic steel plates. 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 periphery of the secondary spool 35. The outer core 45 has a laminate made of a plurality of magnetic steel plates laminated together, and a coating layer made of an insulating resin that covers the outer periphery of the laminate. The outer circumferential core 45 is formed into a rectangular cylindrical shape that penetrates in the vertical direction. The primary coil 20 , the secondary coil 30 , and the central core 40 are arranged inside the outer peripheral core 45 . The outer peripheral core 45 surrounds these in the left-right direction (the above-mentioned axial direction) and the depth direction (perpendicular to the plane of the paper), that is, on the sides. A magnet 72 is provided between one side portion of the outer core 45 and one end of the central core 40 to generate a magnetic flux in the magnetic path in the opposite direction to the magnetic flux generated in the primary coil 20.

A connector 55 is formed on the side wall portion 52 of the case 50 so as to extend along the axial direction of the central core 40 . A connecting terminal 73 electrically connected to the igniter 70 is arranged inside the connector 55.

A cylindrical protrusion 57 that protrudes downward is formed on the bottom 53 . A high voltage terminal 76 electrically connected to the secondary coil 30 via a high voltage connection terminal 74 is inserted inside the protrusion 57 . 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 resin 80 from the bottom 53 to the vicinity of the end 59. The resin 80 is poured in a liquid state from the opening 51 and then heated and hardened. The distance from the upper end 51a of the opening 51 to the upper surface 80a of the resin 80 is a first distance h1. Note that 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 due to heating. The first distance h1 is the distance from the end 51a to the lowest part of the surface 80a.

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

As shown in FIGS. 2 and 4, in the case 50, the inner edges of the four corners 58 of the upper end 59 are provided with first holes extending from the upper end 51a of the opening 51 to a second distance h2. A vertical groove 64 is formed respectively. That is, the first longitudinal groove 64 extends from the upper end 51 a of the opening 51 to the thinnest part of the thin wall portion 60 at the inner edge of the corner portion 58 . The cross-sectional shape of the first vertical groove 64 is triangular (V-shaped).

In the case 50, second vertical grooves 68 extending from the upper end 51a of the opening 51 to a second distance h2 are formed in the outer edges of the four corners 58 of the upper end 59, respectively. . That is, the second longitudinal groove 68 extends from the upper end 51 a of the opening 51 to the thinnest part of the thin wall portion 60 at the outer edge 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 positions of the first vertical groove 64 and the second vertical groove 68 match. That is, the first vertical groove 64 and the second vertical groove 68 are opposed to each other.

Next, a method for manufacturing the ignition coil 10 will be explained.

First, the case 50 is created by integrally molding an insulating resin using a mold or the like. Specifically, the case 50 is shaped like a rectangular cylinder with a bottom and has an opening 51 formed in the upper part 51a, and a second distance h2 from the upper part 51a of the opening 51 is provided along the circumferential direction of the opening 51. A case 50 in which an annular thin wall portion 60 is formed is created.

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

Next, in a vacuum environment, a predetermined amount of thermosetting and electrically insulating liquid resin (resin before thermosetting) is poured into the case 50 from the opening 51. The predetermined amount is an amount that allows the resin 80 after thermosetting to cover and protect the primary coil 20, secondary coil 30, central core 40, outer core 45, igniter 70, etc. The liquid resin poured into the case 50 impregnates the gaps within 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 thermosetting. The distance from the liquid level of the liquid resin to the upper end 51a of the opening 51 is determined in such a way that the ignition coil 10 is not tilted or external force such as vibration is applied to the ignition coil 10 when the ignition coil 10 is moved to the heating process. The distance is such that leakage of liquid resin from the opening 51 can be suppressed even if the opening 51 is opened. That is, the case 50 is designed such that the distance from the surface of the liquid resin to the upper end 51a of the opening 51 is such that the liquid resin does not leak.

However, if the case 50 is designed so that the distance from the liquid level of the liquid resin to the upper end 51a of the opening 51 is long, the first distance h1 after thermosetting the resin becomes long, and the ignition coil 10 becomes large. This is not desirable because it causes In this regard, leakage of the liquid resin and enlargement of the ignition coil 10 are suppressed by the following steps.

Subsequently, the ignition coil 10 is placed on a conveyor (moving device) and moved to a heating process. Specifically, a plurality of ignition coils 10 are placed on a pallet (loading table), and the pallet is placed on a conveyor. The conveyor moves the pallet horizontally to the heating process. At this time, there is a risk that the pallet (ignition coil 10) may be tilted or vibration may be applied to the pallet, causing the liquid level to fluctuate. In particular, an ignition coil that has a plurality of primary coils and can input additional energy tends to be large in size and has a large opening area. In such a large ignition coil 10, the difference in height that occurs when the ignition coil 10 is tilted is large, and the exposed surface area of the liquid resin is large, so the liquid resin is likely to leak from the opening 51. However, since the case 50 is designed such that the distance from the surface of the liquid resin to the upper end 51a of the opening 51 is long, leakage of the liquid resin from the opening 51 cannot be suppressed. , a large coil particularly has a physique-suppressing effect.

Subsequently, in a heating step, the ignition coil 10 is held substantially horizontally, and the liquid resin is heated and hardened using a heating device. Liquid resin contracts slightly when heated. Furthermore, in the process of heating and curing, the viscosity of the liquid resin decreases, promoting impregnation into the gaps between the primary coil 20, secondary coil 30, central core 40, outer core 45, etc. The surface 80a of the resin 80 after curing is reduced. The distance from the upper end 51a of the opening 51 to the upper surface 80a of the resin 80 is the first distance h1, which is longer than the second distance h2.

Subsequently, as shown in FIG. 5, the ignition coil 10 is fixed with a 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 upper end 59 of the case 50 where the opening 51 is formed is cut (divided) along the groove 62 by the blade E of the cutting device. At this time, inside the case 50, the surface 80a of the resin 80 is located at a lower position than the thin portion 60, so 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 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 wall portion 60 is formed is lower than the strength of the portion where the thin wall portion 60 is not formed. Therefore, even if the first distance h1 is increased in order to suppress leakage of liquid resin, the upper end 59 where the opening 51 is formed in the case 50 can be cut along the thin wall portion 60. . As a result, leakage of liquid resin and enlargement of the ignition coil 10 can be suppressed without providing a cover member.

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

- The thin wall portion 60 is formed by forming a groove 62 in the outer peripheral edge of the case 50. According to this configuration, compared to a configuration in which the thin wall portion 60 is formed by forming a groove 62 on the inner peripheral edge of the case 50, the thin wall portion 60 is formed at the groove 62 (i.e., the thin wall portion 60 ) can be easily visually confirmed, and the work of cutting the case 50 becomes easier.

Note that the above embodiment can be modified and implemented as follows. The same parts as those in the above embodiment are given 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 separated using pliers P, nippers, or the like.

- The case 50 has a square tube shape with a bottom and an opening 51 formed at an upper end 59. For this reason, the case 50 has four side walls 52 (surfaces) and four corners 58 (corners). In the case 50, first vertical grooves 64 extending from the upper end 51a of the opening 51 to the second distance h2 are formed in the inner edges of the four corners 58 of the upper end 59, respectively. has been done. Therefore, when cutting the end portion 59 of the case 50 along the thin wall portion 60 using pliers P, nippers, etc., by cutting the end portion 59 along the first vertical groove 64, the end portion of the case 50 can be cut on each side of the case 50. 59 can be divided. Therefore, the end portion 59 of the case 50 can be easily separated.

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

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

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

- As shown in FIG. 11, instead of the grooves 62, 162, a plurality of recesses 262 may be formed along the circumferential direction of the opening 51 at the end 59 of the case 50. The thin portions 260 are formed by forming recesses 262 in the outer peripheral edge of the case 50, respectively. With this configuration as well, the upper end 59 of the case 50 in which the opening 51 is formed can be cut along the plurality of thin parts 260. As shown in FIG. 12, the number of recesses 262 can also be changed. Further, the cross-sectional shape of the recess 262 is not limited to a trapezoid, but may be any shape such as a rectangle, a triangle, or a semicircle.

- The first vertical groove 64 and the second vertical groove 68 may be formed only in the two diagonal corner portions 58. Moreover, the first vertical groove 64 can also be omitted. Further, the second vertical groove 68 can also be omitted.

- The case 50 can also be formed into a hexagonal tube shape with a bottom or a cylindrical shape with a bottom.

- The thin parts 60, 260 can also be formed by forming the grooves 62, 162, 62A to 62D, and the recess 262 in the inner peripheral edge of the case 50.

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

DESCRIPTION OF SYMBOLS 10...Ignition coil, 20...Primary coil, 30...Secondary coil, 50...Case, 51...Opening, 51a...End, 59...End, 60...Thin wall part, 60a...Thin wall part, 60b...Thin wall part, 60c ... Thin wall portion, 60d... Thin wall portion, 80... Resin, 80a... Surface, 260... Thin wall portion.

Claims (7)

An ignition coil (10) comprising a case (50) housing a primary coil (20) and a secondary coil (30), and a resin (80) filled inside the case,
The case has a bottomed cylindrical shape with 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 a first distance (h1),
In the case, a thin wall portion (60, 60a) is provided along the circumferential direction of the opening at a second distance (h2, h21 to h24) shorter than the first distance from the end of the opening in the predetermined direction. ~60d, 260) is formed,
The case has a bottomed square cylindrical shape with the opening formed at the end in the predetermined direction,
In the case, inner edges of the four corners (58) of the end in the predetermined direction are provided with first longitudinal grooves (64) that extend only to the second distance from the end in the predetermined direction of the opening. are each formed into an ignition coil. An ignition coil (10) comprising a case (50) housing a primary coil (20) and a secondary coil (30), the inside of the case being filled with a resin (80),
The case has a bottomed cylindrical shape with an opening (51) formed at an end (59) in a predetermined direction,
In the case, a thin wall portion (60, 60a to 60d, 260 ) is formed,
The case has a bottomed square cylindrical shape with the opening formed at the end in the predetermined direction,
In the case, inner edges of the four corners (58) of the end in the predetermined direction are provided with first longitudinal grooves (64) that extend only to the second distance from the end in the predetermined direction of the opening. are each formed into an ignition coil. The case has a bottomed square cylindrical shape with 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 a portion of the second distance is formed on an outer edge of each of the four corners (58) of the end in the predetermined direction. The ignition coil according to claim 1 or 2 , wherein the ignition coil is formed. An ignition coil (10) comprising a case (50) housing a primary coil (20) and a secondary coil (30), and a resin (80) filled inside the case,
The case has a bottomed cylindrical shape with 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 a first distance (h1),
In the case, a thin wall portion (60, 60a) is provided along the circumferential direction of the opening at a second distance (h2, h21 to h24) shorter than the first distance from the end of the opening in the predetermined direction. ~60d, 260) is formed,
The case has a bottomed square cylindrical shape with 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 a portion of the second distance is formed on an outer edge of each of the four corners (58) of the end in the predetermined direction. The ignition coil is formed. An ignition coil (10) comprising a case (50) housing a primary coil (20) and a secondary coil (30), the inside of the case being filled with a resin (80),
The case has a bottomed cylindrical shape with an opening (51) formed at an end (59) in a predetermined direction,
In the case, a thin wall portion (60, 60a to 60d, 260 ) is formed,
The case has a bottomed square cylindrical shape with 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 a portion of the second distance is formed on an outer edge of each of the four corners (58) of the end in the predetermined direction. The ignition coil is formed. The ignition coil according to any one of claims 1 to 5 , wherein the thin wall portion (60, 60a to 60d) is formed continuously over the entire circumference in the circumferential direction of the opening. The ignition coil according to claim 6 , wherein the thin wall portion (60, 60a to 60d) is formed by forming a groove in the outer peripheral edge of the case.

Images