CN108630417B

CN108630417B - Ignition coil for internal combustion engine

Info

Publication number: CN108630417B
Application number: CN201810245684.XA
Authority: CN
Inventors: 篠原笃史
Original assignee: Diamond Jiebula Motor Co ltd
Current assignee: Diamond Jiebula Motor Co ltd
Priority date: 2017-03-24
Filing date: 2018-03-23
Publication date: 2022-03-01
Anticipated expiration: 2038-03-23
Also published as: CN108630416A; CN113223834A; CN108630417A

Abstract

The invention provides a rectangular ignition coil device which achieves miniaturization and light weight. In the ignition coil device (2), an outer peripheral iron core portion (40) of a coil body (14) includes: a pair of upright portions (53) extending from both ends of the I-shaped core (38) toward the open face side; and a linking part (54) which is bridged between the two upright parts and exposes the part on the opening surface side from the gap filler (18). The upright setting portion is opposed to an inner wall (28) of the housing (12). In the at least one upstanding location, the corners of the outer surface thereof and the outer surface of the link portion have rounded corners. The end on the bottom surface side of the round is set as a lower end (P1), the end on the opening surface side of the round is set as an upper end (P2), and when the contact point between the surface on the opening surface side of the gap filler and the outer peripheral core portion between the upright setting portion and the inner wall of the housing is set as a contact point (Pe), the contact point is located between the lower end and the upper end in the direction perpendicular to the opening surface.

Description

Ignition coil for internal combustion engine

Technical Field

The present invention relates to an ignition coil device for an internal combustion engine.

Background

As a typical ignition coil device for an internal combustion engine, there are a "pen type" in which a coil portion is accommodated in a plugged hole (plug hole) of the engine, and a "rectangular type" in which a coil portion is disposed above a plugged hole. The pen-type ignition coil device is suitable for space saving, and the structure of the coil is limited by the shape or size of the closed hole. In recent years, ignition coil devices are required to have higher output voltages than ever before because of higher engine performance and fuel consumption. In recent years, rectangular ignition coil devices that have a degree of freedom in shape and are easily adaptable to high output voltages have been widely used.

In manufacturing the rectangular ignition coil device, the coil body is accommodated in a box-shaped case having an open upper surface. The coil body includes: a primary coil; a secondary coil located outside the primary coil; an I-shaped iron core penetrating the center of the primary coil; and an outer peripheral core passing through the case opening side of the secondary coil from one end of the "I" core and reaching the other end of the "I" core. A gap generated inside the case when the coil body is accommodated in the case is filled with a gap filler composed of a thermosetting resin. The secondary coil generating a high voltage is insulated from the outside by the gap filler. In order to reduce the amount of gap filler, the opening surface side of the outer peripheral core is exposed to the outside from the gap filler. An example of a rectangular ignition coil device is disclosed in japanese patent application laid-open No. 2014-179459.

[ Prior art documents ]

[ patent document ]

Patent document 1 Japanese patent laid-open No. 2014-179459

Disclosure of Invention

Problems to be solved by the invention

With the increasing demand for smaller and lighter engines, ignition coil devices are required to be further smaller and lighter. Therefore, in the rectangular type ignition coil device, the gap between the case and the coil body is reduced. In particular, a narrow portion is present in a gap between the outer peripheral core and the inner wall of the housing. When the liquid gap filler is injected into the housing, the liquid level of the gap filler in the gap rises due to the capillary phenomenon compared with other portions. This causes the gap filler to leak from the housing. If the height of the inner wall of the case is increased to prevent leakage of the gap filler, the ignition coil is increased in size and the mass thereof is increased.

The invention aims to provide a rectangular ignition coil device which achieves miniaturization and light weight.

Means for solving the problems

The ignition coil device of the present invention includes:

a coil body which combines the I-shaped iron core and the コ -shaped iron core to form a closed magnetic circuit,

a case accommodating the coil body, an

A gap filler made of an insulating resin filling the gap inside the case;

the コ -shaped iron core is integrally formed with: 2 upright installation parts arranged at both ends of the I-shaped iron core, a frame connecting part connected to each of the upright installation parts, and a rounded part formed on an outer peripheral surface of a connecting part between the upright installation parts and the frame connecting part, wherein the コ -shaped iron core comprises: a cover part which is at least covered on the surface of the iron core of the upright setting part, and a cover part which is arranged in a mode of covering the connecting part;

the linking part is arranged closer to the opening side of the housing than the I-shaped iron core, and the cover part has a curved surface part which is arranged at a position where a part of the linking part is exposed from the gap filler and is formed corresponding to the round part;

the interface between the gap filler and the external air is in contact with the curved surface portion.

Preferably, the cover portion has a portion exposing a core surface of the link portion, and the cover portion is attached so as to cover the portion.

Preferably, an end of the curved portion on the housing bottom surface side is a lower end P1, an end of the curved portion on the opening side is an upper end P2, and a contact point Pe at which the boundary surface contacts the curved portion between the upright portion and the inner wall of the housing is located between the lower end P1 and the upper end P2 in a direction perpendicular to the opening surface of the housing (vertical direction).

Preferably, when an end of the inner wall of the housing on the opening side is an end E, the end E is located between the lower end P1 and the upper end P2 in the vertical direction.

Preferably, when a portion of the cover portion facing a portion of the link portion where the core surface is exposed is an opposing portion, the end E includes a portion disposed at a position lower than the opposing portion in the vertical direction.

Effects of the invention

In the coil body of the ignition coil device of the present invention, the upright portion of the outer peripheral core portion is opposed to the inner wall of the case. The outer surface of the upright portion and the outer surface of the link portion of the outer peripheral core portion have rounded corners. When a contact point Pe between the surface of the gap filler on the opening surface side and the outer peripheral core portion is set between the upright portion and the inner wall of the housing, the contact point Pe is located between the rounded bottom surface side end P1 and the opening surface side end P2 in the direction perpendicular to the opening surface. Due to this curvature, the width of the gap between the outer peripheral core portion and the inner wall of the case at the opening surface side than the lower end P1 is larger than the width of the gap at the bottom surface side than the lower end P1. This suppresses the rise of the liquid level in the gap due to the capillary phenomenon when injecting the gap filler into the housing. The difference between the height of the liquid surface in the gap and the height of the liquid surface in other positions is small. Therefore, even if the contact Pe is positioned on the bottom side of the upper end P2, the gap filling portion can be buried in the portion of the coil body that needs to be insulated. By positioning the contact point Pe on the bottom surface side of the upper end P2, the amount of gap filler to be filled can be reduced. Further, the height of the inner wall of the housing can be reduced by positioning the contact point Pe on the bottom surface side of the upper end P2. In the ignition coil, a smaller volume and mass are achieved. In the ignition coil device, miniaturization and light weight are realized.

Drawings

Fig. 1 is a perspective view showing an ignition coil device according to an embodiment of the present invention.

Fig. 2 is an exploded perspective view of the ignition coil device of fig. 1.

Fig. 3 is a sectional view taken along line III-III of fig. 1.

Fig. 4 is an enlarged cross-sectional view of a part of the coil part of fig. 3.

Fig. 5 is an exploded perspective view of the coil body of fig. 2.

Detailed Description

Hereinafter, the present invention will be described in detail based on preferred embodiments with reference to the accompanying drawings as appropriate.

Fig. 1 shows an ignition coil device 2 according to an embodiment of the present invention. The ignition coil device 2 is of a rectangular shape. In fig. 1, an arrow X indicates the front of the ignition coil device 2. Otherwise, it is the rear. The arrow Y indicates the right direction of the ignition coil device 2. Otherwise, the left direction. The arrow Z indicates the upward direction of the ignition coil device 2. Otherwise, the direction is downward. Fig. 2 is an exploded perspective view of the ignition coil device 2 of fig. 1. Fig. 3 is a sectional view taken along line III-III of fig. 1. Fig. 4 is a cross-sectional view of a portion of the ignition coil device 2 of fig. 3 enlarged. The arrows X, Y and Z have the same meaning in fig. 2 to 4. The ignition coil device 2 includes a main body 4, a connector portion 6, a flange portion 8, and a high-voltage output portion 10.

The body 4 is located at the center of the ignition coil device 2. The body 4 is box-shaped. As shown in fig. 1 to 3, the body 4 includes a case 12, a coil body 14, an igniter 16, and a gap filler 18. In fig. 2, the gap filler 18 is omitted.

As shown in fig. 2, the case 12 has a box shape with a hollow inside. The upper surface of the housing 12 is open. That is, the upper surface of the housing 12 is an open surface. The connector portion 6 extends from the front surface of the housing 12, the flange portion 8 extends from the rear surface of the housing 12, and the high-voltage output portion 10 extends from the surface (bottom surface) opposite to the opening surface of the housing 12. In this embodiment, the housing 12 is formed integrally with the connector portion 6, the flange portion 8, and the high-voltage output portion 10. The housing 12 is made of resin. Examples of preferable materials for the case 12 include PBT (polybutylene terephthalate), PPS (polyphenylene sulfide), and PET (polyethylene terephthalate).

As shown in fig. 2 and 3, the igniter 16 is housed in the housing 12. As is apparent from fig. 1 and 3, with respect to the igniter 16, the entirety thereof is buried by the gap filler 18. The igniter 16 is located between the coil body 14 and the connector portion 6. The igniter 16 is located on the front side of the coil body 14. The igniter 16 includes an element housing portion 20 and a plurality of terminals 22. In this embodiment, the igniter 16 includes 6 terminals 22. The element accommodating portion 20 has a box shape. The terminals 22 protrude upward from the upper surface of the element insertion portion 20, respectively. The terminals 22 protrude from the opening surface side of the element placement portion 20.

As shown in fig. 1-3, the coil body 14 is housed in the case 12. In fig. 3, a broken line M indicates a surface (upper surface) on the opening surface side of the gap filler 18. Which shows the upper surface of the gap filler 18 on the side surface sides of the coil body 14 (left and right sides of the coil body 14). As shown in fig. 1 and 3, the coil body 14 has a portion of its opening surface side exposed to the outside from the upper surface of the gap filler 18. Another portion of the coil body 14 is buried by the gap filler 18. The coil body 14 includes a primary bobbin 30, a primary coil 32, a secondary bobbin 34, a secondary coil 36, an "I" core 38, and an outer peripheral core portion 40.

The primary bobbin 30 is cylindrical. The primary bobbin 30 extends in the front-rear direction. The primary bobbin 30 is made of resin. The primary coil 32 is formed by winding a primary electric wire 46 around the outer periphery of the primary bobbin 30. In fig. 3, a cross section of the primary coil form 30 and a cross section of the primary electric wire 46 wound thereon are shown. Typically, the primary wire 46 has about 100 turns. A typical material of the primary wire 46 is copper (Cu).

The secondary bobbin 34 is cylindrical. The secondary bobbin 34 extends in the front-rear direction. The secondary former 34 is located outside the primary coil 32. The secondary bobbin 34 is made of resin. As shown in fig. 3, the secondary bobbin 34 includes: a trunk 48; and a plurality of flanges 50 projecting outward from the trunk 48.

The secondary coil 36 is disposed coaxially with the primary coil 32 outside the primary coil 32. The secondary coil 36 is formed by winding a secondary electric wire 52 around the outer periphery of the secondary bobbin 34. The secondary wire 52 is wound around the outer periphery of the trunk 48 between the adjacent 2 flanges 50. Typically, the number of turns of the secondary wire 52 is 8000 to 15000 turns. A typical material of the secondary wire 52 is copper (Cu).

As shown in fig. 3, the "I" core 38 extends through the center of the primary coil 32. Typically, the "I" core 38 is constructed of silicon steel.

The outer peripheral core portion 40 is constituted by a main portion 41, a cover 42, and a cover 44. The main section 41 reaches the other end of the "I" word core 38 from one end of the "I" word core 38 through the opening surface side of the secondary coil 36. Typically, the main portion 41 is composed of silicon steel. The main portion 41 and the "I" core 38 form a magnetic loop (loop) of the core.

The cover 42 is overlaid on the main portion 41. The cover 42 covers a portion of the main portion 41 on the opening face side. As shown in fig. 1 and 3, the cover 42 is exposed from the gap filler 18. The cover 42 protects the main portion 41 from the outside. The cover 42 is made of resin having excellent durability. Examples of preferable materials for the cover 42 include PBT, PPS, and PET.

The cover 44 covers the main portion 41. The cover 44 covers both side surfaces of the main portion 41. As shown in fig. 2 and 3, the cover 44 also covers the front and rear surfaces of the main portion 41. That is, the cover 44 covers 4 surfaces perpendicular to the surface (upper surface) on the opening side of the main portion 41. As shown in fig. 3, the cover 44 covers the inner face of the main portion 41 (the face opposite to the secondary coil 36). The cover 44 covers the main portion 41 so that the main portion 41 does not directly contact the gap filler 18. The cover 44 is made of an elastomer having a property of being easily peeled off from the gap filler 18. The cover 44 may be made of a resin less brittle than the gap filler 18. The cover 44 prevents cracks in the gap filler 18 due to expansion and contraction of the main portion 41 caused by heat.

In the outer peripheral core portion 40, a portion extending from both ends of the "I" core 38 toward the opening surface side is referred to as an upright-disposed portion 53. The portion that is bridged between these upright portions 53 is referred to as a link portion 54. In other words, the outer peripheral core portion 40 ("コ" -shaped iron core) includes the link portion 54 and the pair of standing portions 53. In addition, a round corner part is formed between the upright part and the connecting frame part, and the part is a curved surface. The upright portions 53 are opposed to the inner walls 28 of the housing 12, respectively. In this embodiment, one upright setting portion 53 is adjacent to the igniter 16. The igniter 16 is located between the upstanding portion 53 and the inner wall 28 of the housing 12 opposite thereto. Therefore, the gap between the standing portion 53 and the inner wall 28 of the housing 12 opposed thereto is larger than the gap between the other standing portion 53 and the inner wall 28 of the housing 12 opposed thereto.

In this embodiment, the outer peripheral core portion 40 includes the cover 42 and the cover 44, but the outer peripheral core portion 40 may not include the cover 42. The outer peripheral iron core 40 may not include the cover 44. The outer peripheral core portion 40 may be constituted only by the main portion 41.

When the coil body 14 and the igniter 16 are accommodated in the case 12, the gap filler 18 fills a gap generated in the case 12. The gap filler 18 is made of a thermosetting resin. The opening surface side portion of the link portion 54 protrudes outward from the upper surface of the gap filler 18. The opening surface side portion of the main portion 41, the opening surface side portion of the cover 44, and the opening surface side portion of the cover 42 protrude outward from the upper surface of the gap filler 18. The inner surface of the main portion 41 and the secondary coil 36 are located on the bottom surface side of the upper surface of the gap filler 18. In other words, the gap between the inner surface of the main portion 41 and the secondary coil 36 is filled with the gap filler 18. As shown in fig. 3, the gap filler 18 fills the gap between the inner wall 28 of the housing 12 and the coil body 14 and igniter 16. The gap filler 18 insulates the secondary coil 36, which generates a high voltage, from other components. Therefore, a thermosetting resin having excellent insulating properties is selected as a material of the gap filler 18. In order to fill the resin into the corners of the gap in the housing 12, a thermosetting resin having a low viscosity is selected as the material of the gap filler 18.

Fig. 4 is a cross-sectional view of a portion of the ignition coil device 2 of fig. 3 enlarged. In the figure, the vicinity of one upright setting portion 53 is shown. This is the standing portion 53 on the side not adjacent to the igniter 16. As shown in the drawing, the outer surface of the upright portion 53 is constituted by the outer surface of the cover 42 and the outer surface of the cover 44 from the opening surface side thereof. A gap is provided between the upright portion 53 and the inner wall 28 of the housing 12 opposed thereto. In the gap, a gap filler 18 is filled. The upper surface of the gap filler 18 in the gap is slightly raised toward the opening surface side than the upper surface M on the side surface side of the coil body 14 by the capillary phenomenon.

As shown in fig. 4, corners of the outer surface of the upright portion 53 and the outer surface of the frame portion 54 have rounded corners. In fig. 4, reference numeral P1 denotes the rounded bottom surface side end (lower end). Reference numeral P2 denotes an end (upper end) on the opening face side of the round. Reference numeral Pe denotes a junction of the upper surface of the gap filler 18 in the gap and the outer peripheral core portion 40. As shown in the drawing, in the ignition coil device 2, the contact point Pe is located between the rounded bottom surface side end P1 and the opening surface side end P2 in the direction perpendicular to the opening surface (vertical direction). In the ignition coil device 2, the contact point Pe is located between the lower end P1 and the upper end P2 in the vertical direction. Due to the rounded corner, the width of the gap between the upright portion 53 and the inner wall 28 of the housing 12 on the opening surface side from the lower end P1 is larger than the width of the gap on the bottom surface side from the lower end P1.

In fig. 4, reference symbol E denotes an end of the inner wall 28 of the housing 12 on the opening surface side, which is opposed to the upright setting portion 53. As shown in the drawing, the end E of the inner wall 28 of the housing 12 is located between the rounded bottom surface side end P1 and the opening surface side end P2 in the up-down direction. In the ignition coil device 2, the end E is located between the lower end P1 and the upper end P2 in the vertical direction.

As described above, the ignition coil device 2 includes the connector portion 6, the flange portion 8, and the high voltage output portion 10 in addition to the main body 4. The connector portion 6 is located in front of the body 4. The connector portion 6 has a cylindrical shape. The connector portion 6 is open at the front thereof. As shown in fig. 3, the connector section 6 includes a connector terminal 56 on the inside. Although not shown, the plurality of connector terminals 56 are juxtaposed in the left-right direction. When the ignition coil device 2 is mounted on a vehicle, the connector terminal 56 is connected to a control unit (ECU) of the vehicle. The connector terminals 56 are also connected to the terminals 22 of the igniter 16.

The flange portion 8 is located rearward of the body 4. The flange 8 is provided with a hole 58 penetrating vertically. Although not shown, the ignition coil device 2 is fixed to the engine by inserting a bolt through the hole 58 and a hole provided in the engine. The flange portion 8 firmly fixes the ignition coil device 2 to the engine.

The high voltage output part 10 is located at the lower side of the body 4. Although not shown, the high voltage output section 10 includes a high voltage terminal inside thereof. The high voltage terminal is connected to a terminal of the secondary coil 36. Although not shown, when the ignition coil device 2 is mounted on a vehicle, the high-voltage output portion 10 is inserted into the blind hole. The high voltage terminal is connected to a spark plug.

The ignition coil device 2 operates as follows. A control signal from a control device of the automobile is sent to the igniter 16 via the connector terminal 56. The igniter 16 is a switch for controlling the on/off of the current of the primary coil 32. In response to the control signal, the igniter 16 conducts or cuts off the current of the primary coil 32. As described above, the number of turns of the secondary wire 52 is large compared to the number of turns of the primary wire 46. Therefore, by changing the current of the primary coil 32, a high voltage of several tens kV is generated in the secondary coil 36. The high voltage generated in the secondary coil 36 is applied to the spark plug through the high voltage output unit 10. Whereby the gasoline is ignited. The control device controls the timing of the ignition of the gasoline by the spark plug.

In manufacturing the ignition coil device 2, the case 12, the coil body 14, and the igniter 16 are prepared. As shown in fig. 2, the housing 12 is formed integrally with the connector portion 6, the flange portion 8, and the high-voltage output portion 10. As shown in fig. 2, a coil body 14 and an igniter 16 are accommodated in the housing 12. The coil body 14 and the igniter 16 are disposed at predetermined positions inside the case 12. The terminal 22 of the igniter 16 is connected to the connector terminal 56 and the primary coil 32. A liquid gap filler 18 is filled into the interior of the housing 12. The gap filler 18 is injected from the upper portion of the igniter 16. The gap filler 18 is injected until the liquid level of the gap filler 18 reaches a predetermined height. The gap filler 18 is then heated and cured. Thereby, the ignition coil device 2 is obtained.

The operation and effect of the present invention will be described below.

In the coil body 14 of the ignition coil device 2 of the present invention, the upright portion 53 of the outer peripheral core portion 40 faces the inner wall 28 of the case 12. The corners of the outer surface of the standing portion 53 and the outer surface of the linking portion 54 of the outer peripheral core portion 40 have rounded corners. When a contact point Pe between the surface of the gap filler 18 on the opening surface side and the outer peripheral core portion 40 is set as a contact point Pe between the upright portion 53 and the inner wall 28 of the housing 12, the contact point Pe is located between the rounded bottom surface side end P1 and the opening surface side end P2 in the direction perpendicular to the opening surface. Due to the round, the width of the gap between the outer peripheral core portion 40 and the inner wall 28 of the case 12 at the opening surface side than the lower end P1 is larger than the width of the gap at the bottom surface side than the lower end P1. This suppresses the rise of the liquid level in the gap due to the capillary phenomenon when the gap filler 18 is injected into the housing 12. The difference between the height of the liquid surface in the gap and the height of the liquid surface in other positions is small. Therefore, even if the contact Pe is positioned on the bottom side of the upper end P2, the gap filling part 18 can be buried in the portion of the coil body 14 that needs to be insulated. By locating the contact point Pe on the bottom surface side of the upper end P2, the amount of gap filler 18 to be filled can be reduced. Further, the height of the inner wall 28 of the housing 12 can be reduced by positioning the contact point Pe on the bottom surface side of the upper end P2. In the ignition coil, a smaller volume and mass are achieved. In the ignition coil device, miniaturization and light weight are realized.

As described above, the end E is located between the lower end P1 and the upper end P2 in the up-down direction. By positioning the lower end P1 on the bottom surface side from the end E, the width of the gap between the outer peripheral core portion 40 and the inner wall 28 of the case 12 on the opening surface side from the lower end P1 is larger than the width of the gap on the bottom surface side from the lower end P1. This suppresses the rise of the liquid level in the gap due to the capillary phenomenon when the gap filler 18 is injected into the housing 12. Even if the end E is located further to the bottom side than the upper end P2, leakage of the gap filler 18 from the case 12 is suppressed. By locating the end E on the bottom surface side of the upper end P2, the ignition coil device 2 achieves a smaller volume and mass. In the ignition coil device 2, downsizing and weight reduction are achieved.

In fig. 4, a double arrow H indicates a height in the up-down direction from the lower end P1 to the upper end P2. The double arrow L1 indicates the distance in the up-down direction from the lower end P1 to the junction Pe. The ratio of the distance L1 to the height H (L1/H) is preferably 20% or more. By setting the ratio (L1/H) to 20% or more, the rounded corners effectively suppress the rise of the liquid level in the gap due to the capillary phenomenon. The ratio (L1/H) is preferably 60% or less. By setting the ratio (L1/H) to 60% or less, the amount of gap filler 18 to be filled can be reduced. By setting the ratio (L1/H) to 60% or less, the height of the inner wall 28 of the housing 12 can be reduced. In the ignition coil device 2, downsizing and weight reduction are achieved.

In fig. 4, a double arrow L2 indicates a distance in the up-down direction from the lower end P1 to the end E. The ratio of the distance L2 to the height H (L2/H) is preferably 30% or more. By setting the ratio (L2/H) to 30% or more, the gap between the upright portion 53 and the inner wall 28 of the housing 12 can be effectively enlarged on the opening surface side of the lower end P1. In the ignition coil device 2, the rise of the liquid level in the gap due to the capillary phenomenon is effectively suppressed. The ratio (L2/H) is preferably 70% or less. By setting the ratio (L2/H) to 70% or less, the volume of the housing 12 can be reduced more effectively. In the ignition coil device 2, downsizing and weight reduction are achieved.

As shown in fig. 3, in this embodiment, with respect to the two standing portions 53, corners of the outer surface thereof and the outer surface of the shelf portion 54 each include a rounded corner. It is also possible that, for only one of the upright portions 53, the corners of the outer surface thereof with the outer surface of the shelf portion 54 include rounded corners. The contact point Pe may be located between the rounded bottom-surface-side end P1 and the opening-surface-side end P2 with respect to only one upright portion 53. In this case, in the upright portion 53 having a smaller clearance from the inner wall 28 of the housing 12, the corner between the outer surface thereof and the outer surface of the shelf 54 is preferably rounded, and the contact point Pe is preferably located between the rounded bottom surface side end P1 and the opening surface side end P2.

Epoxy resin is preferable as a material of the gap filler 18. The epoxy resin has high insulating property. The epoxy resin can insulate the high voltage portion of the secondary coil 36 with a small volume. This contributes to miniaturization of the ignition coil device 2. Thus, miniaturization and excellent insulating performance are realized. Further, the viscosity of the epoxy resin before curing is low. The gap filler 18 can be spread over the corners of the gap within the housing 12. Voids are inhibited from remaining in the gap filler 18. This realizes high-voltage resistance and high-quality insulation performance in the ignition coil device 2.

The embodiment of fig. 5 is an exploded perspective view of the coil body 14 of fig. 1, and is provided with a cover 42. Fig. 5 is a view showing the coil body 14 exploded into the cover 42 and other parts. The cover 42 is covered on the upper portion of the outer peripheral core portion 40. The cover 42 covers a portion of the outer peripheral core portion 40 on the opening surface side. As shown in fig. 1, the cover 42 is exposed from the gap filler 18. The cover 42 protects the outer peripheral core portion 40 from contact with the outside. The cover 42 is made of resin having excellent durability. Examples of preferable materials for the cover 42 include PBT, PPS, and PET.

As shown in the figure, the lid portion has a curved laminated structure corresponding to the rounded corner portion of the outer peripheral core. Hereinafter, this is referred to as a curved surface portion.

In the embodiment shown in fig. 5, the barrier members 37 for cracks extend outward from both sides of the cover 42 toward the bottom surface side and in the width direction of the cover 42. However, the crack stopper member 37 may not extend in this direction.

The cover 44 covers the outer peripheral iron core 40. As shown in fig. 5, the cover 44 covers one side surface of the outer peripheral core portion 40. Although not shown, the cover 44 also covers the other side surface of the outer peripheral core portion 40. As shown in fig. 3 and 5, the cover 44 also covers the front and rear surfaces of the outer peripheral core portion 40. That is, the cover 44 covers 4 surfaces perpendicular to the surface (upper surface) of the outer peripheral core portion 40 on the opening side. As shown in fig. 5, the cover 44 covers portions of the front and rear ends of the upper surface of the outer peripheral core portion 40. Further, as shown in fig. 3, the cover 44 covers the inner surface of the outer peripheral core portion 40 (the surface facing the secondary coil 36). The cover 44 covers the outer peripheral iron core 40 so that the outer peripheral iron core 40 is not in direct contact with the gap filler 18. The cover 44 is made of an elastomer having a property of being easily peeled off from the gap filler 18. The cover 44 may be made of a resin less brittle than the gap filler 18. The cover 44 prevents cracks in the gap filler 18 due to expansion and contraction of the outer peripheral core portion 40 caused by heat generation.

When the coil body 14 and the igniter 16 are accommodated in the case 12, the gap filler 18 fills a gap generated inside the case 12. The gap filler 18 is made of a thermosetting resin. As shown in fig. 3, the opening surface side portion of the outer peripheral core portion 40, the opening surface side portion of the cover 44, and the opening surface side portion of the cover 42 protrude outward from the upper surface of the gap filler 18. The crack stopper 37, the inner surface of the outer core portion 40, the secondary coil 36, and the igniter 16 are located on the bottom surface side of the upper surface of the gap filler 18. In other words, the crack barrier member 37, the inner surface of the outer peripheral core portion 40, the secondary coil 36, and the igniter 16 are buried by the gap filler 18. As shown in fig. 3, the gap filler 18 fills the gap between the inner wall of the case 12 and the coil body 14 and igniter 16. Further, the gap filler 18 fills the gap between the secondary coil 36 and the outer peripheral core portion 40 inside the coil body 14. The gap filler 18 insulates the secondary coil 36, which generates a high voltage, from other components. Therefore, a thermosetting resin having excellent insulating properties is selected as a material of the gap filler 18. In order to fill the resin into the corners of the gap in the housing 12, a thermosetting resin having a low viscosity is selected as the material of the gap filler 18.

As described above, the ignition coil device 2 includes the connector portion 6, the flange portion 8, and the high voltage output portion 10 in addition to the main body 4. The connector portion 6 is located in front of the body 4. The connector portion 6 has a cylindrical shape. The connector portion 6 is open at the front thereof. As shown in fig. 3, the connector section 6 includes a connector terminal 56 on the inside. Although not shown, the plurality of connector terminals 56 are juxtaposed in the left-right direction. When the ignition coil device 2 is mounted on a vehicle, the connector terminal 56 is connected to a control unit (ECU) of the vehicle. The connector terminals 56 are also connected to the terminals of the igniter 16.

When the coil body 14 and the igniter 16 are accommodated in the case 12, the gap filler 18 fills a gap generated inside the case 12. The gap filler 18 is made of a thermosetting resin. The opening surface side portion of the link portion 54 protrudes outward from the upper surface of the gap filler 18. The opening surface side portion of the main portion 41, the opening surface side portion of the cover 44, and the opening surface side portion of the cover 42 protrude outward from the upper surface of the gap filler 18. The inner surface of the main portion 41 and the secondary coil 36 are located on the bottom surface side of the upper surface of the gap filler 18. In other words, the gap between the inner surface of the main portion 41 and the secondary coil 36 is filled with the gap filler 18. As shown in fig. 3, the gap filler 18 fills the gap between the inner wall 28 of the housing 12 and the coil body 14 and igniter 16. The gap filler 18 insulates the secondary coil 36, which generates a high voltage, from other components. Therefore, a thermosetting resin having excellent insulating properties is selected as a material of the gap filler 18. In order to fill the resin into the corners of the gap in the housing 12, a thermosetting resin having a low viscosity is selected as the material of the gap filler 18.

As shown in fig. 4, corners of the outer surface of the upright portion 53 and the outer surface of the frame portion 54 have rounded corners. In fig. 4, reference numeral P1 denotes an end (lower end) on the bottom surface side of the curved portion of the cover 42. Reference numeral P2 denotes an end (upper end) of the opening surface side of the round (curved surface portion). Reference numeral Pe denotes a junction of the upper surface of the gap filler 18 in the gap and the outer peripheral core portion 40. As shown in the drawing, in the ignition coil device 2, the contact point Pe is located between the bottom-side end P1 of the rounded corner (curved surface portion) and the opening-surface-side end P2 in the direction perpendicular to the opening surface (vertical direction). In the ignition coil device 2, the contact point Pe is located between the lower end P1 and the upper end P2 in the vertical direction. Due to the rounded corner, the width of the gap between the upright portion 53 and the inner wall 28 of the housing 12 on the opening surface side from the lower end P1 is larger than the width of the gap on the bottom surface side from the lower end P1.

As described above, the present invention includes: a coil body which combines the I-shaped iron core and the コ -shaped iron core to form a closed magnetic circuit; a case that houses the coil body; and a gap filler made of an insulating resin filling the gap inside the case. Further, the コ -shaped iron core is integrally formed with: 2 standing portions arranged at both ends of the I-shaped iron core, a frame connecting portion connected to each of the standing portions, and a rounded portion formed on an outer peripheral surface of a connecting portion between the standing portions and the frame connecting portion; the コ -shaped iron core includes: a cover part which is at least covered on the surface of the iron core of the upright setting part, and a cover part which is arranged in a mode of covering the connecting part. Further, the linking portion is disposed on the opening side of the housing with respect to the I-shaped core, and the cover portion has a curved portion which is disposed at a position where a part of the linking portion is exposed from the gap filler and is formed corresponding to the rounded portion. Further, an interface between the gap filler and the outside air is in contact with the curved surface portion.

Therefore, the ignition coil of the present invention has the clearance between the outer peripheral core portion and the inner wall of the case on the opening surface side with respect to the lower end P1 larger in width than the clearance on the bottom surface side with respect to the lower end P1 due to the round of the curved surface portion. This suppresses the rise of the liquid level in the gap due to the capillary phenomenon when injecting the gap filler into the housing. Also, the difference between the height of the liquid surface in the gap and the height of the liquid surface in other positions is small. Therefore, even if the contact Pe is positioned on the bottom side of the upper end P2, the gap filling portion can be buried in the portion of the coil body that needs to be insulated.

Further, the contact point Pe can be positioned on the bottom surface side of the upper end P2, thereby reducing the amount of gap filler to be filled. Further, the height of the inner wall of the housing can be reduced by positioning the contact point Pe on the bottom surface side of the upper end P2. In this way, the ignition coil of the present invention is intended to reduce the size and mass thereof, and to reduce the size and weight of the device.

In fig. 4, a portion of the cover portion facing a portion of the link portion where the core surface is exposed is visible. Hereinafter, this portion is referred to as an opposing portion. In the example of the same drawing, the end E is provided with a portion disposed at a position lower than the opposing portion in the vertical direction (Z-axis direction) of the ignition coil. Accordingly, the height of the side wall of the housing can be designed to be lower, which is advantageous in reducing the volume and mass and realizing further downsizing and weight reduction of the device.

Further, the housing depicted in fig. 1 to 4 has: a flange portion; and a side wall which is erected on the flange portion and has a rectangular section in a cross section parallel to the opening surface of the housing. In addition, one end of the I-shaped iron core is inserted into the rectangular portion of the case. In this example, the gap filler is filled between the rectangular portion and one end of the I-shaped core.

As a result, the groove serving as the gap portion is filled with resin throughout the gap, although the space is narrow, and no unnecessary gap is formed. This eliminates the cause of cracking and the like, and contributes to the increase in life.

In fig. 1 to 4, shapes defined as follows are depicted: the longitudinal direction of the I-shaped iron core is taken as the axial center direction, a groove part is formed between the rectangular part and one end of the I-shaped iron core, the groove part parallel to the axial center direction in the groove parts is taken as the 1 st groove, and the groove part vertical to the axial center direction in the groove parts is taken as the 2 nd groove. Then, according to the same drawing, it is understood that an interface between the gap filler and the outside air is formed in both the 1 st groove and the 2 nd groove.

As a result, in each of the grooves serving as the gap portions, the gap filling resin spreads over the narrow groove regardless of the X-axis direction and the Y-axis direction, and no unnecessary gap is formed.

In particular, the boundary surface formed in the slot portion is preferably formed in a shape of "コ" along the contour of one end of the aforementioned "I" -shaped core. Thus, in the ignition coil according to this example, the entire circumference of the groove portion is filled with the gap filling resin, and no remaining gap is formed.

As shown in fig. 4, the inner surface 28 of the side wall preferably faces the outer surface of the cover, and a gap is preferably formed to locally increase the distance from the outer surface of the cover. Thereby, the gap filling resin fills the gap portion from the Z-axis lower side, and is lifted up to the Z-axis upper side. That is, in this gap, the gap filling resin is filled from below in the Z-axis direction over the entire resin interface by the above operation. A typical example of such a shape is shown in fig. 4, and the distance is preferably increased by the step portion.

Industrial applicability

The ignition coil device described above is used for various internal combustion engines.

Description of the reference numerals

2. ignition coil device

4. body

6. connector part

8. flange part

10. high voltage output part

12. outer shell

14. coil body

16. igniter

18. gap filler

20. element built-in part

22. terminal

28. inner wall of housing

30. primary coil former

32. primary coil

34. secondary coil former

36 secondary coil

38. I-shaped iron core

40. outer peripheral iron core

41 main part

42. lid

44 cover

46. Primary wire

48. trunk part

50. flange

52. Secondary wire

53. upright setting part

54. connecting frame part

56. connector terminal

58. hole

Claims

1. An ignition coil for an internal combustion engine, comprising:

a case accommodating the coil body, an

A gap filler made of an insulating resin filling the gap inside the case;

the interface between the gap filler and the external air is contacted with the curved surface part;

a narrow part is arranged in a gap between the inner wall of the shell and the cover part;

the curved portion suppresses the liquid level of the gap filler in a liquid state from rising in the narrow portion compared to other portions due to capillary phenomenon,

the cover portion is made of an elastomer having a property of easily peeling off the gap filler, or a resin having a lower brittleness than the gap filler.

2. The ignition coil for an internal combustion engine according to claim 1,

the cover portion has a portion where the core surface of the link portion is exposed, and the cover portion is attached so as to cover the portion.

3. The ignition coil for an internal combustion engine according to claim 1 or 2,

the end of the curved portion on the bottom surface side of the housing is a lower end (P1), the end of the curved portion on the opening side is an upper end (P2), and when a contact point where the dividing surface and the curved portion are in contact is a contact point (Pe) between the upright portion and the inner wall of the housing, the contact point (Pe) is located between the lower end (P1) and the upper end (P2) in a vertical direction which is a direction perpendicular to the opening surface of the housing.

4. An ignition coil for an internal combustion engine according to claim 3,

when the end of the inner wall of the housing on the opening side is an end (E), the end (E) is located between the lower end (P1) and the upper end (P2) in the vertical direction.

5. The ignition coil for an internal combustion engine according to claim 4,

when a portion of the cover portion facing a portion of the link portion where the core surface is exposed is defined as an opposing portion, the end (E) includes a portion disposed at a position lower than the opposing portion in the vertical direction.