ignition coil

Abstract

The ignition coil includes a center core, a first core element, and a second core element. The first core element includes a first core facing portion facing the front core surface of the center core and a first core side portion extending rearward from the first core facing portion. The second core element includes a second core facing portion facing the rear core surface of the center core and a second core side portion extending forward from the second core facing portion. The first core facing portion has an end face that contacts a portion of the second core side portion to create a first contact area. Similarly, the second core facing portion has an end face that contacts a portion of the first core side portion to create a second contact area. Both the first and second contact areas are shaped to move forward close to the first core side portion. This structure improves the productivity of the ignition coil.

Description

Technical Field

[0001] This disclosure relates to an ignition coil. Background Technology

[0002] Japanese Patent First Publication No. 2009-290147 teaches an ignition coil having a central core disposed inside a primary coil and a secondary coil, a permanent magnet disposed at an end of the central core, and a first side core and a second side core. The first side core and the second side core partially face the corresponding ends of the central core along its length or axis. The first side core and the second side core surround the central core in a ring shape.

[0003] Both the first and second side cores are approximately L-shaped and connected together in a circular shape. The first side core contacts the first end of the central core, on which the permanent magnet is disposed. The second side core contacts the second end of the central core, opposite to the first end. The ends of the first and second side cores face a direction perpendicular to the axis of the windings of the primary and secondary coils (also referred to as the vertical direction) and are connected to each other.

[0004] An air gap between the first side core and the permanent magnet, or between the second side core and the second end of the center core, will cause a decrease in the performance of the ignition coil.

[0005] To mitigate the aforementioned drawbacks, the disclosed ignition coil is designed with a connection end having a first side core and a second side core, the shape of which has a surface extending in an axial direction parallel to the central core. In the assembly process of the ignition coil, the first and second side cores are assembled with the central core and the permanent magnet in the following manner: the ends of the first and second side cores face each other in the vertical direction; the end of the first side core is placed in contact with the end of the second side core; and the first and second side cores are slid in the vertical direction to move their ends closer together, thereby aligning the end of the first side core with the end of the second side core in the vertical direction.

[0006] However, the ignition coil disclosed above requires pressing the first and second side cores together in both the vertical and axial directions of the central core during assembly, thus complicating the assembly process. Therefore, there is still room for improvement in ignition coil productivity. Summary of the Invention

[0007] Therefore, the purpose of this disclosure is to provide an ignition coil that can improve its productivity.

[0008] According to one aspect of the invention, an ignition coil is provided, comprising: (a) a primary coil and a secondary coil magnetically coupled to each other; (b) a central core disposed inside the inner periphery of the primary coil and the secondary coil, the central core having a first surface and a second surface aligned with the first surface in an axial direction of the primary coil and the secondary coil; (c) a first core element comprising a first core facing portion and a first core side portion, the first core facing portion facing the first surface of the central core, the first core side portion extending from the first core facing portion in a first axial direction defined as opposite to a second axial direction along the axial directions of the primary coil and the secondary coil, the first core element being disposed outside the outer periphery of the primary coil and the secondary coil; and (d) a second core element comprising a second core facing portion and a second core side portion, the second core facing portion facing the second surface of the central core, the second core side portion extending from the second core facing portion in a second axial direction and located on the side of the central core opposite to the first core side portion in an orthogonal direction perpendicular to the axial directions of the primary coil and the secondary coil, the second core element being disposed outside the outer periphery of the primary coil and the secondary coil. The first core face portion has an end face that faces away from the first core side portion in an orthogonal direction. The end face of the first core face portion makes face-to-face contact with a portion of the second core side portion to create a first contact area. The second core face portion has an end face that faces away from the second core side portion in an orthogonal direction. The end face of the second core face portion makes face-to-face contact with a portion of the first core side portion to create a second contact area. Each of the first contact area and the second contact area is geometrically oriented to approach the first core side portion facing the second core side portion in an orthogonal direction in a second axial direction.

[0009] As described above, the ignition coil has a first contact area and a second contact area, both of which are shaped to approach the first core side in the second axial direction; in other words, they extend at a certain angle relative to the centerline of the outer core composed of the first and second core elements. This facilitates the assembly of the first and second core elements, thereby improving the productivity of the ignition coil.

[0010] The symbols in parentheses in the claims are only used to indicate the correspondence with the components discussed in the following embodiments, and do not limit the technical scope of the invention. Attached Figure Description

[0011] The invention will be more fully understood from the detailed description given below and the accompanying drawings of preferred embodiments of the invention. However, it should not be construed as limiting the invention to the specific embodiments, as these are merely for illustrative and understanding purposes.

[0012] In the attached diagram:

[0013] Figure 1 This is a cross-sectional view showing the ignition coil according to the first embodiment;

[0014] Figure 2 It is along Figure 1 A cross-sectional view taken from line II-II;

[0015] Figure 3 This is a perspective view showing the outer core of the first embodiment;

[0016] Figure 4 It means Figure 1 An exploded view of the outer core of the ignition coil shown;

[0017] Figure 5 This is a cross-sectional view of the ignition coil before the second core element of the ignition coil is attached to the first core element in the first embodiment;

[0018] Figure 6 This is a cross-sectional view showing the first core element and the second core element placed in contact with each other during the assembly process of the ignition coil in the first embodiment;

[0019] Figure 7 This is a cross-sectional view showing a first core element and a second core element positioned relative to each other in an ignition coil according to the first embodiment;

[0020] Figure 8 This is a cross-sectional view showing the center core, magnet, and outer core of the ignition coil according to the second embodiment; and

[0021] Figure 9 This is a cross-sectional view showing the center core, magnet, and outer core of the ignition coil according to the third embodiment. Detailed Implementation

[0022] First Embodiment

[0023] The following will refer to Figures 1 to 7 Describe the structure of ignition coil 1.

[0024] like Figure 1 As shown, the ignition coil 1 includes a primary coil 11, a secondary coil 12, a center core 2, a first core element 4, and a second core element 5.

[0025] The primary coil 11 and the secondary coil 12 are magnetically coupled to each other. The center core 2 is located inside the inner circumference of the primary coil 11 and the secondary coil 12.

[0026] like Figure 1 , 3 As clearly shown in Figure 4, the first core element 4 includes a first core face portion 41 and a first core side portion 42. (As illustrated in Figure 4) Figure 1As clearly shown, the first core face portion 41 faces the front core surface (also referred to as the first surface) of the central core 2 in the longitudinal direction of the central core 2 (i.e., the axial direction of the primary coil 11 and the secondary coil 12). The first core side portion 42 faces the periphery of the central core 2 and extends rearward (also referred to as the first axial direction) from the first core face portion 41 in the axial direction X (also referred to as the coil axial direction) of the ignition coil 1. The first core element 4 is disposed outside the outer periphery of the primary coil 11 and the secondary coil 12.

[0027] Similarly, such as Figure 1 , 3 As shown in Figure 4, the second core element 5 includes a second core facing portion 51 and a second core side portion 52. From Figure 2 As can be seen, the second core face portion 51 faces the rear core surface 22 (also referred to as the second surface) of the central core 2 along the length direction of the central core 2. The second core side portion 52 extends forward (also referred to as the second axis) from the second core face portion 51 in the axial direction X of the ignition coil 1. The second core side portion 52 is disposed on the side of the central core 2 opposite to the first core side portion 42 in the direction Y (also referred to as the orthogonal direction) perpendicular to the coil axis X. The second core element 5 is disposed on the outer periphery of the primary coil 11 and the secondary coil 12.

[0028] like Figure 1 and Figure 3 As clearly shown, the first core side portion 41 has an end face 411 that faces away from the first core side portion 41 along the orthogonal direction Y. The end face 411 directly contacts a portion (i.e., the end face) of the second core side portion 52 to create a first contact area 61. Similarly, the second core side portion 51 has an end face 511 that faces away from the second core side portion 52 along the orthogonal direction Y. The end face 511 directly contacts a portion (i.e., the end face) of the first core side portion 42 to create a second contact area 62. Each of the first contact area 61 and the second contact area 62 is tilted at a given angle relative to the coil axis X. In other words, each of the first contact area 61 and the second contact area 62 is shaped or oriented forward toward the first core side portion 42 facing the second core side portion 51 in the orthogonal direction Y. In other words, each of the first contact area 61 and the second contact area 62 has a first edge and a second edge aligned with each other in the X direction. The first contact area 61 and the second contact area 62 are shaped or oriented such that the first edge is positioned closer to the first core side 42 in the X direction than the second edge.

[0029] The structure of ignition coil 1 will be described in detail below.

[0030] As indicated herein, the coil axis X is the direction along which the axis of each winding in the primary coil 11 and the secondary coil 12 extends. In the following discussion, the coil axis direction X will also be referred to simply as the X direction. The forward direction of the ignition coil 1 will also be referred to as the first X direction (i.e., the second axis described above). As described herein, the front side is the region on the central core 2 where the magnet 3, which will be described in detail later, is mounted. The rearward direction of the ignition coil 1 will also be referred to as the second X direction (i.e., the first axis described above). As described herein, the rear side is the region along the second X direction away from the front side. The terms "front" or "rear" used in this discussion are for convenience only and do not specifically refer to the orientation of the ignition coil 1 installed in the vehicle. The orthogonal direction Y will also be referred to simply as the Y direction. The direction perpendicular to the X and Y directions will also be referred to as the Z direction.

[0031] In this embodiment, the ignition coil 1 is used, for example, with an internal combustion engine in a motor vehicle or a combined heat and power system. The ignition coil 1 is connected to a spark plug (not shown) installed in the internal combustion engine and is used to apply high voltage to the spark plug to generate an electric spark.

[0032] like Figure 1 and Figure 2 As clearly shown, the central core 2 has a length extending along the X direction. For example, the central core 2 is made of multiple magnetic steel plates, each made of a soft magnetic material and stacked overlapping each other in the Z direction. Figure 1 As can be seen, the central core 2 has a basic T-shaped cross-section extending perpendicular to the Z direction. Specifically, the central core 2 includes a rectangular column 23 and a flange 24. The column 23 has a length extending in the X direction. The flange 24 protrudes outward from the front end of the column 23 in the opposite direction parallel to the Y direction. The flange 24 provides an increased area for the front core surface 21 of the central core 2 to allow a magnet 3 with a large cross-sectional area extending perpendicular to the X direction to be mounted on the front core surface 21. The ignition coil 1 has a magnet 3 facing the front core surface 21 and arranged to contact the front core surface 21.

[0033] Magnet 3 is a rectangular plate with a given thickness in the X direction. Viewed from the X direction, magnet 3 has the same dimensions as the front core surface 21 and occupies substantially the entire area of ​​the front core surface 21. Magnet 3 is used to magnetically bias the central core 2, thereby increasing the change in magnetic flux Φ when the primary coil 11 is de-energized, thus increasing the voltage induced in the secondary coil 12 to increase the output voltage of the ignition coil 1. The larger the cross-sectional area of ​​magnet 3, the higher the magnetic bias applied to the central core 2, unless the material of magnet 3 is changed. The first core element 4 and the second core element 5 are configured to surround the central core 2 and magnet 3 along the X and Y directions, respectively.

[0034] like Figure 3As can be seen, each of the first core element 4 and the second core element 5 is made of multiple magnetic steel plates, all made of soft magnetic material and stacked on top of each other to have a thickness in the Z direction. The first core element 4 and the second core element 5 are assembled together to complete the annular outer core 6. The outer core 6, together with the central core 2, forms a magnetic circuit through which the magnetic flux Φ generated around the primary coil 11 and the secondary coil 12 when the primary coil 11 is de-energized passes. The outer core 6 is a rectangular frame shape, having two transverse sides 63 extending in the Y direction and two longitudinal sides 64 extending in the X direction.

[0035] like Figure 1 and Figure 3 As shown, each lateral side 63 of the outer core 6 has two protruding cores 65 aligned with each other along the Y direction at its end. The protruding cores 65 protrude from the end of each lateral side 63 along the X direction to the outside of the outer core 6. In other words, the protruding cores 65 of each lateral side 63 define a recessed core portion 66 located at the midpoint of the length of the lateral side 63 along the Y direction and hollow in the X direction. Each recessed core portion 66 occupies the entire thickness of each first core face portion 41 and second core face portion 51 along the Z direction, thus having open ends opposite to each other in the Z direction.

[0036] like Figure 2 As shown, the outer core 6 is larger in the Z direction than the central core 2 and the magnet 3. In other words, the outer core 6 has ends that are aligned with each other in the Z direction and protrude outwards from the central core 2 and the magnet 3 in the Z direction.

[0037] like Figure 1 , 3 As clearly shown in Figure 4, each of the first core element 4 and the second core element 5 has a substantially L-shaped cross-section extending perpendicular to the Z direction. In this embodiment, the first core element 4 and the second core element 5 are identical in structure and shape to each other. Specifically, when one of the first core element 4 and the second core element 5 is rotated 180° about a centerline extending along the Y direction, the first core element 4 and the second core element 5 are mirror images of each other.

[0038] The first core element 4 has a plate-like first core surface portion 41 with a thickness in the X direction. For example... Figure 1 As can be seen, the first core-facing portion 41 extends along the Y direction and faces the front surface 2 of the central core 2 through the magnet 3. The first core-facing portion 41 has a rear surface that is in direct contact with the front surface of the magnet 3.

[0039] like Figure 1 , 3 As shown in Figure 4, the first core face of the portion 41 faces the Y2 direction (i.e., in...). Figure 1 , 3The end face 411 (to the left in direction 4) is formed as flat or smooth and tapers relative to the longitudinal centerline of the ignition coil 1. As viewed in cross-section of the first core face portion 41, the end face 411 is inclined vertically at a given angle (excluding 0 degrees) relative to the X and Y directions. The end face 411 of the first core face portion 41 is located in the region where the left core protrusion 65 of the first core face portion 41 is located. In other words, a portion of the end face 411 defines a portion of the surface of the core protrusion 65. The core recess 66 in the Y1 direction (i.e., Figure 1 , 3 The end face 411 of the first core face portion 41 is located away from the end face 41 of the first core face portion 41 at a given interval in the right direction (as in 4). The first core side portion 42 extends rearward from the end face of the first core face portion 41 facing the Y1 direction.

[0040] The first core side portion 42 includes a first straight portion 420 and a first protrusion 421. The first straight portion 420 extends straight rearward from the first core facing portion 41 in the X direction. The first straight portion 420 has a first end and a second end aligned with the first end in the X direction. The first end faces forward. The second end faces rearward. The first protrusion 421 protrudes from the rear end (i.e., the second end) of the first straight portion 420 in the Y2 direction. The first protrusion 421 has a first protruding end face 421a facing away from the first straight portion 420 in the Y2 direction. In other words, as Figure 3 and 4 As shown, the first protruding end face 421a is positioned away from the first straight portion 420 and has a front edge that is continuous with the inner surface of the first straight portion 420 via an inwardly (i.e., forward) inner surface 421b of the first protrusion 421. The shape of the first protruding end face 421a is flat or smooth, and it extends parallel to the end face 511 of the second core face portion 51. Figure 1 and 3 As shown, the first core element 4 is configured to have a first protruding end face 421a, which faces and directly contacts the end face 511 of the second core facing portion 51.

[0041] like Figure 1 , 3 As shown in Figure 4, the second core surface portion 51 of the second core element 5 is plate-shaped and has a thickness along the X direction. Figure 1 As clearly shown, the second core surface portion 51 extends along the Y direction and has a front surface (i.e., inner surface) facing and positioned to directly contact the rear core surface 22.

[0042] like Figure 1 , 3 As shown in Figure 4, the second core face of the portion 51 faces the Y1 direction (i.e., in...). Figure 1 , 3The end face 511 (to the right in direction 4) is shaped to be flat or smooth and tapers relative to the longitudinal centerline of the ignition coil 1. As viewed in cross-section of the second core face portion 51, the end face 511 is inclined vertically at a given angle (excluding 0 degrees) relative to the X and Y directions. In other words, the end face 511 extends parallel to the first protruding end face 421a of the first protrusion 421 of the first core element 4. The end face 511 of the second core face portion 51 is located in the region where the right core protrusion 65 exists. The core recess 66 of the second core face portion 51 is spaced away from the second core face portion 51 in the Y2 direction (i.e., Figure 1 , 3 The end face 511 of the second core face portion 51 (to the right in direction 4) is substantially the same in size or area as the first protruding end face 421a of the first protrusion 421. The entire end face 511 of the second core face portion 51 coincides with the entire first protruding end face 421a of the first protrusion 421; in other words, the entire end face 511 of the second core face portion 51 is in direct contact with the entire first protruding end face 421a of the first protrusion 421. The end face 511 of the second core face portion 51 and the first protruding end face 421a of the first protrusion 421 face each other in direct contact to create a second contact area 62. The second core side portion 52 extends forward from the end of the second core face portion 51 facing the Y2 direction.

[0043] The second core side portion 52 includes a second straight portion 520 and a second protrusion 521. The second straight portion 520 extends straight forward from the second core facing portion 51 in the X direction. The second straight portion 520 has a first end and a second end aligned with the first end in the X direction. The first end faces forward. The second end faces backward. The second protrusion 521 protrudes from the front end (i.e., the first end) of the second straight portion 520 in the Y1 direction. The second protrusion 521 has a second protruding end face 521a, which faces away from the second straight portion 520 in the Y1 direction. In other words, as Figure 3 and Figure 4 As can be seen, the second protruding end face 521a is positioned away from the second straight portion 520 and has a rear edge, which is continuous with the inner surface of the second straight portion 520 via the inward-facing (i.e., rearward-facing) inner surface 521b of the second protrusion 521. The second protruding end face 521a is shaped to be flat or smooth and extends parallel to the end face 411 of the first core face portion 41. In this embodiment, the end face 411 of the first core face portion 41, the first protruding end face 421a of the first protrusion 421, the end face 511 of the second core face portion 51, and the second protruding end face 521a of the second protrusion 521 extend substantially parallel to each other. Figure 1 and Figure 3 As shown, the second core element 5 is configured to have a second protruding end face 521a, which faces and directly contacts the end face 411 of the first core face portion 41.

[0044] The second protruding end face 521a of the second protrusion 521 is the same in size or area as the end face 411 of the first core facing portion 41. The entire second protruding end face 521a of the second protrusion 521 coincides with the entire end face 411 of the first core facing portion 41; in other words, the entire second protruding end face 521a of the second protrusion 521 directly contacts the entire end face 411 of the first core facing portion 41. The second protruding end face 521a of the second protrusion 521 and the end face 411 of the first core facing portion 41 directly contact each other to create a first contact area 61. Both the first contact area 61 and the second contact area 62 are shaped to have flat or smooth surfaces and extend parallel to each other.

[0045] like Figure 4 As shown, the dimension (i.e., width) of at least one of the end face 411 of the first core face portion 41 defining the first contact area 61 and the second protruding end face 521a of the second protrusion 521 is greater in the X direction than the dimension of a given portion of the first core face portion 41 away from the first contact area 61 in the Y1 direction. Specifically, in this embodiment, both the end face 411 of the first core face portion 41 and the second protruding end face 521a of the second protrusion 521 have a dimension L1, which is greater in the X direction than the dimension L2 of the portion of the first core face portion 41 in which the core recess 66 is formed. Similarly, the dimension (i.e., width) of at least one of the end face 511 of the second core face portion 51 defining the second contact area 62 and the first protruding end face 421a of the first protrusion 421 is greater in the X direction than the dimension of a given portion of the second core face portion 51 away from the second contact area 62 in the Y2 direction. Specifically, in this embodiment, both the end face 511 of the second core face portion 51 and the first protruding end face 421a of the first protrusion 421 have a dimension L3, which is larger in the X direction than the dimension L4 of the portion of the second core face portion 51 in which the core recess 66 is formed. In this embodiment, dimension L1 is equal to dimension L3, and dimension L2 is equal to dimension L4.

[0046] like Figure 1 and Figure 2 As clearly shown, the ignition coil 1 is provided with a primary spool (i.e., a bobbin) 71, into which a central core 2 is embedded. The primary spool 71 has a primary coil 11 wound around its outer periphery. The central core 2 has a front core surface 21 and a rear core surface 22 exposed to the outside of the primary spool 71. The primary spool 71, together with the connector 72, constitutes the connector module 7.

[0047] Connector module 7 has a connector 72 forming its front end. Connector 72 is a connector used for electrically connecting ignition coil 1 to an external device. Figure 1As shown, connector module 7 has a connector wall 73 that enables the connector module 7 to connect or engage with the housing 15 of ignition coil 1. Connector 72 protrudes forward from connector wall 73 of connector module 7. Figure 2 As can be seen, the connector wall 73 and the primary spool 71 are connected together by the connecting wall 74. The connecting wall 74 is offset along the Z direction from the central axis of the first core face portion 41 and the magnet 3.

[0048] Connector 72, connector wall 73, connecting wall 74, and primary spool 71 constitute connector module 7. Specifically, connector module 7 is formed by placing the metal connecting terminals and center core 2 of connector 72 into a molding die, and then injecting electrically insulating resin into the molding die.

[0049] like Figure 2 As shown, connector module 7 has a mounting chamber 75, which is surrounded by connector wall 73, connecting wall 74 and primary spool 71 and formed as a concave recess. Mounting chamber 75 has an opening oriented in the Z direction, and also has openings oriented in the Y1 and Y2 directions. The first core face 41 of outer core 6 and igniter 13 (described in detail later) are inserted into mounting chamber 75.

[0050] Igniter 13 is positioned in front of outer core 6 within mounting chamber 75. Igniter 13 is used to control the energization or de-energization of primary coil 11. Figure 1 As can be seen, the igniter 13 is positioned in front of the outer core 6, between the core protrusions 65 facing each other along the Y direction on the transverse side 63. The igniter 13 faces the front core recess 66 of the outer core 6 along the X direction. The dimension (i.e., length) of the igniter 13 along the Y direction is smaller than the dimension along the Y direction of the core recess 66 of the first core facing portion 41. Viewed along the Y direction, the igniter 13 is located inside the core recess 66 of the first core facing portion 41. Although not shown, the igniter 13 is provided with a terminal that extends away from the opening facing the Z direction of the mounting chamber 75 and passes through a hole formed in the connecting wall 74.

[0051] like Figure 1 and 2 As shown, the secondary spool 14 is disposed outside the outer periphery of the primary spool 71. The secondary spool 14 is a hollow cylindrical shape and is made of electrically insulating resin. The primary spool 71 is disposed inside the secondary spool 14. The secondary coil 12 is wound around the outer periphery of the secondary spool 14. The secondary coil 12 is coaxially disposed with the primary coil 11.

[0052] like Figure 1As can be seen, the components of the ignition coil 1 are disposed inside the housing 15 and the connector wall 73 fixed to the housing 15. The housing 15 is made of electrically insulating resin. The housing 15 has an opening that faces away from the Z-direction opening of the mounting chamber 75. A recessed connector recess 151 is formed in the front wall of the housing 15, and the connector wall 73 is mounted in the connector recess 151. The connector recess 151 is formed by cutting a portion of the front wall of the housing 15 into an opening facing the Z-direction. The connector wall 73 of the connector module 7 is mounted in the housing 15 by engaging the connector wall 73 with the connector recess 151 and inserting the connector module 7 into the opening of the housing 15.

[0053] A resin seal 16 is disposed within an inner cavity surrounded by the housing 15 and the connector wall 73. The resin seal 16 is made of, for example, an electrically insulating thermosetting resin. The resin seal 16 hermetically seals the components of the ignition coil 1 disposed within the housing 15 and the connector wall 73.

[0054] The following will refer to Figures 5 to 7 An example describing how the components of ignition coil 1 are mounted in housing 15.

[0055] First, such as Figure 5 As shown, in connector module 7, a primary spool 71 with a primary coil 11 wound on it is inserted into a secondary spool 14 with a secondary coil 12 wound on it. Igniter 13 is inserted into mounting chamber 75. The terminals (not shown) of igniter 13 are mated or soldered to the terminals of connector 72.

[0056] Next, magnet 3 is placed on the front core surface 21 of the center core 2, which is exposed to the outside of connector module 7. Then, magnet 3 is firmly bonded to the front core surface 21 of center core 2 by the magnetic force generated by magnet 3. Magnet 3 is installed in mounting chamber 75 by inserting magnet 3 into the opening of mounting chamber 75 from the Z direction.

[0057] Subsequently, the first core element 4 is inserted into the mounting chamber 75 so that the first core face portion 41 faces and contacts the front surface of the magnet 3. The first core element 4 can be inserted into the mounting chamber 75 along either the Y or Z direction. As described above, the first core face portion 41 of the first core element 4 is positioned to contact the front surface of the magnet 3 in the mounting chamber 75, thereby achieving a secure engagement between the first core face portion 41 and the magnet 3 using the magnetic force generated by the magnet 3. This securely fixes the first core element 4 to the connector module 7 via the magnet 3.

[0058] Next, as Figure 5 and Figure 6As shown, the second core element 5 is assembled with the first core element 4. Specifically, the second core element 5 moves in the Y direction closer to the first core element 4, so that the end face 511 of the second core surface portion 51 of the second core element 5 contacts the first protruding end face 421a of the first protrusion 421 of the first core element 4, and also contacts the second protruding end face 521a of the second protrusion 521 of the second core element 5 contacts the end face 411 of the first core surface portion 41 of the first core element 4. This arrangement is as follows. Figure 6 As shown. The second core surface 51 of the second core element 5 is separated from the rear core surface 22 of the central core 2 by an air gap.

[0059] Subsequently, as Figure 6 and Figure 7 As shown, the second core element 5 is further pressed against the first core element 4 along the Y1 direction, causing the end face 511 of the second core element 5's second core face portion 51 to slide on the first protruding end face 421a of the first protrusion 421 of the first core element 4, and also causing the second protruding end face 521a of the second protrusion 521 to slide on the end face 411 of the first core face portion 41. This causes the second core element 5 to move relative to the first core element 4 along the Y1 direction, and simultaneously forward (i.e., along the Y1 direction). Figure 6 Move in the diagonal direction indicated by the middle arrow. For example... Figure 7 As shown, this movement causes a reduction in the gap between the first core face portion 41 and the second core face portion 51. Finally, the second core face portion 51 of the second core element 5 contacts the rear core surface 22 of the central core 2, causing the first core face portion 41 of the first core element 4 to be magnetically attracted by the magnet 3, thereby forming a firm bond between them. The second core face portion 51 of the second core element 5 is firmly attached to the rear core surface 22 of the central core 2, thereby positioning the second core element 5 relative to the first core element 4 in the X and Y directions.

[0060] like Figure 5 As shown, the igniter 13 and connector 72 are located in front of the outer core 6 just before the first core element 4 and the second core element 5 are about to be attached to each other. Therefore, it is impossible to press the first core element 4 and the second core element 5 in the X direction to position them relative to each other. To eliminate this defect, the ignition coil 1 is designed to position the first core element 4 and the second core element 5 in the X and Y directions only by pressing the second core element 5 in the Y direction to make the first core face 41 contact the front surface of the magnet 3 and also to make the second core face 51 contact the rear core surface 22 of the center core 2.

[0061] In this embodiment, the ignition coil 1 provides the following advantages.

[0062] The first contact area 61 and the second contact area 62 of the ignition coil 1 are shaped to move forward due to being pressed in the Y1 direction. This allows the first core element 4 and the second core element 5 to be assembled with the center core 2 and the magnet 3 in the manner described above, i.e., by moving the first core element 4 and the second core element 5 closer to each other in the Y direction to create the first contact area 61 and the second contact area 62, and then pressing the second core element 5 against the first core element in the Y1 direction, thereby causing the first core element 4 and the second core element 5 to slide at the first contact area 61 and the second contact area 62, thus moving the second core element 5 forward in the Y1 direction. This reduces the gap between the second core surface portion 51 and the first core surface portion 41, such that the first core surface portion 41 subsequently contacts the front surface of the magnet 3, and the second core surface portion 5 also contacts the rear core surface 22 of the center core 2. The first core element 4 and the second core element 5 are positioned relative to each other in the X and Y directions in the manner described above. That is, the first core element 4 and the second core element 5 are pressed together in the Y direction so that the first core surface 41 contacts the front surface of the magnet 3, and the second core surface 51 contacts the rear core surface 22 of the center core 2. This improves the productivity of the ignition coil 1.

[0063] The magnet 3 is disposed between the front core surface 21 of the central core 2 and the first core surface 41 of the first core element 4, thereby improving the productivity of the ignition coil 1. For example, the assembly of the central core 2, magnet 3, first core element 4 and second core element 5 can be achieved by placing the magnet 3 on the front core surface 21 of the central core 2, placing the first core element 4 in front of the magnet 3 so that the magnetic attraction generated by the magnet 3 will join the central core 2, magnet 3 and first core element 4 together, and then attaching the second core element 5 to the first core element 4 that has been joined to the central core 2 and magnet 3.

[0064] Dimensional variations in the first core element 4 or the second core element 5 may cause misalignment between the end face 411 of the first core element 41 and the second protruding end face 521a of the second protrusion 521, or between the first protruding end face 421a of the first protrusion 421 and the end face 511 of the second core element 51, when the first core element 4 and the second core element 5 are attached to each other. This results in a reduction in the area where the first core element 4 and the second core element 5 face each other, thereby increasing the risk of magnetic flux leakage from the outer core 6.

[0065] To avoid the aforementioned problems, as described above, at least one of the end face 411 of the first core face portion 41 that forms the first contact area 61 and the second protruding end face 521a of the second protrusion 521 is shaped to have a size in the X direction that is larger than the size of a given portion of the first core face portion 41 away from the first contact area 61 along the Y1 direction (i.e., toward the first core side portion 42). Furthermore, at least one of the end face 511 of the second core face portion 51 that forms the second contact area 62 and the first protruding end face 421a of the first protrusion 421 is shaped to have a size in the X direction that is larger than the size of a given portion of the second core face portion 51 away from the second contact area 62 along the Y2 direction (i.e., toward the second core side portion 52). This ensures that the end face 411 of the first core face portion 41 and the second core element 5 face each other, in other words, the required area of ​​alignment in the Y direction, and ensures that the end face 511 of the second core face portion 51 and the first core element 4 face each other, in other words, the required area of ​​alignment in the Y direction, thereby minimizing the leakage of magnetic flux from the outer core 6 to ensure the desired capability of the ignition coil 1.

[0066] The front lateral side 63 of the outer core 6 is provided with a core protrusion 65, which crosses the igniter 13 in the Y direction and protrudes forward relative to each other, i.e., protrudes towards the igniter 13 in the X direction. This facilitates the release of heat generated by the igniter 13 from the core protrusion 65 to the outer core 6. The core protrusion 65 does not occupy a portion of the area of ​​the front lateral side 63 facing the igniter 13 in the X direction (i.e., the core recess 66), thereby reducing the size of the ignition coil 1 in the X direction. The rear lateral side 63, like the front lateral side 63, has a core protrusion 65 formed at its end and protruding rearward. This allows the first core element 4 and the second core element 5 to be formed in the same shape, thereby improving the productivity of the outer core 6.

[0067] The first contact area 61 and the second contact area 62 are both shaped to have flat or smooth surfaces and extend parallel to each other. This ensures the desired area of ​​each of the first contact area 61 and the second contact area 62, namely, the contact area between the end face 411 of the first core face portion 41 and the second protruding end face 521a of the second protrusion 521, and the contact area between the end face 511 of the second core face portion 51 and the first protruding end face 421a of the first protrusion 421. This minimizes the risk of air gaps appearing in the first contact area 62 and the second contact area 62, thereby ensuring the required capability of the ignition coil 1.

[0068] The first core side portion 42 includes a first straight portion 420 and a first protrusion 421. Similarly, the second core side portion 52 includes a second straight portion 520 and a second protrusion 521. The first protruding end face 421a of the first protrusion 421 forms a second contact area 62. The second protruding end face 521a of the second protrusion 521 forms a first contact area 61. In other words, the first contact area 61 is formed by the end face (i.e., the second protruding end face 521a) of the second protrusion 521 protruding from the second straight portion 520. Similarly, the second contact area 62 is formed by the end face (i.e., the first protruding end face 421a) of the first protrusion 421 protruding from the first straight portion 420. Therefore, for the ignition coil 1 of this embodiment, the first contact area 61 and the second contact area 62 can be generated by a simple structure.

[0069] The entire first protrusion end face 421a of the first protrusion 421 is away from the first straight portion 420 in the Y direction. Similarly, the entire second protrusion end face 521a of the second protrusion 521 is away from the second straight portion 520 in the vertical direction (i.e., the Y direction). This minimizes the risk that undesirable contact between the first core element 4 and the second straight portion 520 or between the second core element 5 and the first straight portion 420 during the assembly of the first core element 4 and the second core element 5 might prevent the first core element 4 and the second core element 5 from sliding relative to each other.

[0070] It is clear from the above discussion that the structure of the ignition coil 1 in this embodiment improves productivity.

[0071] Second Embodiment

[0072] like Figure 8 As shown, the second embodiment differs from the first embodiment in the position of contact or engagement between the first core element 4 and the second core element 5 of the outer core 6.

[0073] Specifically, the end face 411 of the first core element 4's first core face portion 41 is formed to have a front edge continuous with the first end of the bottom surface 661 of the core recess 66 of the front lateral side 63 of the outer core 6. The bottom surface 661 has a first end and a second end aligned with the first end in the Y direction. The first end is closer to the second core side portion 51 than the second end. The dimension of the end face 411 of the first core face portion 41 in the X direction is the same as the dimension of the portion of the first core face portion 41 forming the core recess 66 in the X direction. The bottom surface 661 of the core recess 66 of the rear lateral side 63 has a first end and a second end aligned with the first end in the Y direction. The first end of the bottom surface 661 is closer to the second core side portion 52 than the second end. The second core element 5's second core face portion 51 is formed to have a rear end continuous with the second end of the bottom surface 661 of the core recess 66 of the rear lateral side 63. The end face 511 of the second core face portion 51 is shaped such that its dimension in the X direction is the same as the dimension in the X direction of the portion of the second core face portion 51 that forms the core recess 66. The structure or shape of the first core element 4 and the second core element 5 are identical to each other.

[0074] The other configurations of the ignition coil 1 in the second embodiment are the same as those in the first embodiment.

[0075] Unless otherwise stated, the reference numerals used in the second and subsequent embodiments refer to the same components as in the first embodiment.

[0076] The structure of the ignition coil 1 in the second embodiment provides essentially the same beneficial advantages as in the first embodiment.

[0077] Third Embodiment

[0078] Figure 9 The assembly of the center core 2 and outer core 6 of the ignition coil 1 according to the third embodiment is shown. The third embodiment differs from the first embodiment in the structure of the first contact region 61 and the second contact region 62.

[0079] Specifically, the end face 411 of the first core face portion 41 that forms the first contact area 61 and the end face 511 of the second core face portion 51 that forms the second contact area 62 are both shaped as convex surfaces, which bulge forward diagonally. The first protruding end face 421a of the first protrusion 421 is shaped as a concave surface, the contour of which matches the end face 511 of the second core face portion 51. Similarly, the second protruding end face 521a of the second protrusion 521 is shaped as a concave surface, the contour of which matches the end face 411 of the first core face portion 41. The structure or shape of the first core element 4 and the second core element 5 are identical to each other. The end faces 411 of the first core face portion 41 and the end faces 511 of the second core face portion 51 can be shaped as concave, while the first protruding end face 421a of the first protrusion 421 and the second protruding end face 521a of the second protrusion 521 can be convex.

[0080] The other configurations of the ignition coil 1 in the third embodiment are the same as those in the first embodiment.

[0081] The structure of the ignition coil 1 in the third embodiment provides essentially the same beneficial advantages as in the first embodiment.

[0082] Although the invention has been disclosed with reference to preferred embodiments to facilitate a better understanding of it, it should be understood that the invention can be implemented in various ways without departing from the principles of the invention. Therefore, the invention should be understood to include all possible embodiments and modifications to the illustrated embodiments, which can be implemented without departing from the principles of the invention set forth in the appended claims.

Claims

1. An ignition coil (1), comprising: A primary coil (11) and a secondary coil (12) are magnetically coupled to each other; A central core (2) is arranged inside the inner periphery of the primary coil and the secondary coil, the central core having a first surface (21) and a second surface (22) aligned with the first surface along the axial direction (X) of the primary coil and the secondary coil; A first core element (4) includes a first core facing portion (41) and a first core side portion (42), the first core facing portion facing the first surface of the central core, the first core side portion extending from the first core facing portion in a first axial direction, the first axial direction being defined as being opposite to a second axial direction along the axial direction of the primary coil and the secondary coil, the first core element being disposed outside the outer periphery of the primary coil and the secondary coil. and The second core element (5) includes a second core facing portion (51) and a second core side portion (52). The second core facing portion faces the second surface of the central core. The second core side portion extends from the second core facing portion in the second axial direction and is located on the side of the central core opposite to the first core side portion in an orthogonal direction perpendicular to the axial directions of the primary coil and the secondary coil. The second core element is disposed outside the outer periphery of the primary coil and the secondary coil. The first core face portion has an end face (411) facing away from the first core side portion in the orthogonal direction, and the end face of the first core face portion makes face-to-face contact with a portion of the second core side portion to form a first contact area (61). The second core face portion has an end face (511) facing away from the second core side portion in the orthogonal direction, and the end face of the second core face portion makes face-to-face contact with a portion of the first core side portion to create a second contact area (62). Each of the first contact region and the second contact region is shaped to approach the first core side portion in the second axial direction, wherein the first core side portion faces the second core side portion in the orthogonal direction.

2. The ignition coil according to claim 1, wherein, A magnet (3) is disposed between the first surface of the central core and the first core surface portion of the first core element.

3. The ignition coil according to claim 1, wherein, At least one of the end face of the first core face portion and the surface of the second core side portion that forms the first contact area has a size (L1) that is greater in the axial direction of the primary coil and the secondary coil than the size (L2) of a given portion of the first core face portion located closer to the first core side portion than the first contact area in the orthogonal direction. At least one of the end face of the second core face portion and the surface of the first core side portion that forms the second contact area has a size (L3) that is greater in the axial direction of the primary coil and the secondary coil than the size (L4) of a given portion of the second core face portion located closer to the second core side portion than the second contact area in the orthogonal direction.

4. The ignition coil according to claim 2, wherein, At least one of the end face of the first core face portion and the surface of the second core side portion that forms the first contact area has a size (L1) that is greater in the axial direction of the primary coil and the secondary coil than the size (L2) of a given portion of the first core face portion located closer to the first core side portion than the first contact area in the orthogonal direction. At least one of the end face of the second core face portion and the surface of the first core side portion that forms the second contact area has a size (L3) that is greater in the axial direction of the primary coil and the secondary coil than the size (L4) of a given portion of the second core face portion located closer to the second core side portion than the second contact area in the orthogonal direction.

5. The ignition coil according to any one of claims 1 to 4, wherein, Both the first contact area and the second contact area are shaped to have flat surfaces and extend parallel to each other.

6. The ignition coil according to any one of claims 1 to 4, wherein, The first core side portion includes a first straight portion (420) and a first protrusion (421). The first straight portion extends straight from the first core side portion in the first axial direction and has an end facing the first axial direction. The first protrusion protrudes from the end of the first straight portion toward the second core side portion in the orthogonal direction. The second core side portion includes a second straight portion (520) and a second protrusion (521), the second straight portion extending straight from the second core side portion in the second axial direction and having an end facing the second axial direction, and the second protrusion protruding from the end of the second straight portion toward the first core side portion in the orthogonal direction. The first protrusion has a first protrusion end face (421a), which faces the second core side portion in the orthogonal direction and defines the second contact area. The second protrusion has a second protrusion end face (521a), which faces the first core side portion in the orthogonal direction and defines the first contact area.

7. The ignition coil according to claim 5, wherein, The first core side portion includes a first straight portion (420) and a first protrusion (421). The first straight portion extends straight from the first core side portion in the first axial direction and has an end facing the first axial direction. The first protrusion protrudes from the end of the first straight portion toward the second core side portion in the orthogonal direction. The second core side portion includes a second straight portion (520) and a second protrusion (521), the second straight portion extending straight from the second core side portion in the second axial direction and having an end facing the second axial direction, and the second protrusion protruding from the end of the second straight portion toward the first core side portion in the orthogonal direction. The first protrusion has a first protrusion end face (421a), which faces the second core side portion in the orthogonal direction and defines the second contact area. The second protrusion has a second protrusion end face (521a), which faces the first core side portion in the orthogonal direction and defines the first contact area.

8. The ignition coil according to claim 6, wherein, The entire first protrusion end face of the first protrusion is positioned away from the first straight portion in the orthogonal direction, and the entire second protrusion end face of the second protrusion is positioned away from the second straight portion in the orthogonal direction.

9. The ignition coil according to claim 7, wherein, The entire first protrusion end face of the first protrusion is positioned away from the first straight portion in the orthogonal direction, and the entire second protrusion end face of the second protrusion is positioned away from the second straight portion in the orthogonal direction.

Images