JP5340889B2 - Ignition coil - Google Patents

Description

  The present invention relates to an ignition coil inserted into a plug hole of an internal combustion engine such as an engine, and more particularly, to a pencil type ignition coil having a coil case in which a primary coil and a secondary coil are accommodated coaxially.

  In a pencil-type ignition coil, a configuration in which an appropriate resistor is disposed on the secondary side of the ignition coil to prevent generation of high-frequency noise is described in, for example, Patent Document 1 and Patent Document 2.

Japanese Patent Laid-Open No. 2001-23840 Japanese Patent Laid-Open No. 2002-50528

  In the invention described in the cited document 1, one side of the resistance member is press-fitted into the secondary terminal (T2a) on the base end side and is held by the urging force of the leaf spring member arranged in the secondary terminal (T2a). Yes. On the other hand, the other side of the resistance member is press-fitted into another secondary terminal (T2b) on the other end side, and is held by the urging force of the leaf spring member disposed in the secondary terminal (T2b). And the secondary terminal (T2b) of the front end side is employ | adopted as the structure press-fitted in the recessed part of a high voltage | pressure terminal.

  Thus, in the invention described in the cited document 1, a leaf spring member is required for each of the two secondary terminals (T2a, T2b) on the base end side and the tip end side, and the number of parts increases. There is a problem that the manufacturing cost increases by the amount and the manufacturing process becomes complicated.

  On the other hand, in the fifth embodiment of Cited Document 2, a resistor is housed in the secondary spool extended in the axial direction, and the protruding portion of the high-voltage terminal is inserted into the connection terminal on the tip side of the resistor. The electrical connection is realized.

  In the configuration of the cited document 2, although the number of parts is reduced as compared with the cited document 1, the entire ignition coil extends in the axial direction by the length of the resistor, so that it is impossible to meet the demand for downsizing the ignition coil. Moreover, in the invention of the cited document 2, there is a problem that it is not always easy to assemble each member, such as assembling a substantially cap-shaped high-voltage terminal that opens downward.

  The present invention has been made in view of the above-described problems, and provides an ignition coil that can suppress high-frequency noise without requiring an extra distance in the axial direction, and can be easily assembled with a simple configuration. Objective.

  In order to achieve the above object, an ignition coil according to the present invention includes a primary coil in which a primary winding is wound around a primary bobbin and a secondary coil in which a secondary winding is wound around a secondary bobbin. An ignition coil configured to have a coil case housed in a wire, and attached to a distal end side of the secondary bobbin and electrically connected to the secondary winding, and a proximal end side A high-voltage terminal having a protruding portion protruding toward the distal end and a receiving hole opening on the distal end side, the protruding portion being inserted into the distal end side of the secondary bobbin and electrically connected to the output terminal, and a proximal end A side terminal that is press-fitted into the receiving hole and electrically connected to the high-voltage terminal, and a tip-side terminal that is electrically connected to the spark plug through a conductive spring material, and the coil case The distal end side of is closed by the resistor.

  Preferably, the high-voltage terminal is connected to a main body portion formed in a substantially disc shape, the substantially cylindrical protrusion protruding from the main body portion to the proximal end side, and the distal end side from the main body portion. The housing hole should be formed in the cylindrical portion.

  Further, on the distal end side of the coil case, a boundary opening having a minimum diameter blocked by the resistor, a distal end hole that is enlarged from the boundary opening toward the distal end side and receives the spring material, and the boundary opening It is preferable that a bottom hole whose diameter is expanded from the base end toward the base end side is provided.

  The bottom hole includes a first part that extends in a tapered shape from the boundary port toward the base end side, a second part that extends to the base end side while maintaining an inner diameter substantially the same as the maximum inner diameter of the first part, And a third part having an inner diameter larger than two parts and extending toward the base end side. Here, the inner diameter dimension of the second part of the bottom hole substantially matches the outer diameter dimension of the cylindrical part of the high-voltage terminal, while the inner diameter dimension of the third part of the bottom hole is equal to that of the main body part of the high-voltage terminal. It is optimal that the high-voltage terminal is configured to be positioned at a step portion formed at the boundary position between the second part and the third part of the bottom hole by substantially matching the outer diameter.

  The resistor is preferably formed in a generally cylindrical shape together with the proximal end terminal and the distal end terminal, and the boundary opening of the coil case is preferably closed by the distal end terminal of the resistor. An extension bobbin that protrudes from the cylindrical body of the secondary bobbin in a small cylindrical shape is formed on the distal end side of the secondary bobbin, and the output terminal of the secondary coil is configured by bending and deforming a wire material. A winding part having a start end and a terminal end wound around the outer periphery of the extension part, an axial part extending from the terminal end of the winding part to the tip side substantially orthogonal to the winding part, And a radial portion disposed along the distal end surface of the extension portion substantially orthogonally from the most distal end of the axial direction portion, and the protruding portion of the high-voltage terminal is inserted into the extension bobbin Thus, it is preferable that the protruding portion and the radial direction portion are configured to be in electrical contact.

  The output terminal of the secondary coil is provided with a connecting portion extending in the radial direction from the starting end of the winding portion, and the high voltage side end of the secondary winding is soldered to the connecting portion. Is preferred.

  According to the present invention described above, it is possible to realize an ignition coil that can suppress high-frequency noise without requiring an extra distance in the axial direction, and can be easily assembled with a simple configuration.

It is drawing explaining the ignition coil which concerns on an Example. It is drawing which expands and shows the principal part of FIG. It is drawing which shows the shape of the front end side of a secondary bobbin.

  Hereinafter, the present invention will be described in detail based on examples. FIG. 1 is a diagram showing an outline of an ignition coil according to an embodiment, and shows a plan view (a), a central sectional view (b), and a circuit diagram (c).

  The ignition coil is integrally formed by filling each case with a coil case 1 formed in a substantially cylindrical shape by PPS resin (poly phenylene sulfide) or PBT resin (poly buthylene terephthalete) and then filling with epoxy resin. It has become.

  Specifically, the coil case 1 is divided into a box-shaped base end 1A that opens upward and a main body 1B that extends in a cylindrical shape. A switching element Q is accommodated in the base end 1A of the coil case 1, and the control signal SG and the battery voltage VB are connected to the switching element Q via the connection terminal 2 integrated with the base end 1A. Are supplied (see FIG. 1C).

  On the other hand, a plug boot 3 holding a conductor spring SP is attached to the coil case main body 1B from the distal end side. In FIG. 1, the scales of the plug boot 3 and the coil case 1 are not the same.

  As shown in the circuit diagram of FIG. 1C, the coil case main body 1B includes an electromagnetically coupled primary coil L1 and secondary coil L2, and a resistor 51 connected to the high voltage side of the secondary coil L2. Is housed. The resistor 51 has a resistance value R of about 2 kΩ to 3 kΩ, and suppresses high-frequency noise generated when the spark plug is discharged.

  The primary coil L1 is configured by winding a primary winding 11 around a substantially cylindrical primary bobbin 10, and the secondary coil L2 is formed by winding a secondary winding 21 around a substantially cylindrical secondary bobbin 20. It is configured. In this embodiment, the primary coil L <b> 1 and the secondary coil L <b> 2 are configured coaxially, and the secondary coil L <b> 2 is accommodated inside the primary bobbin 10. Further, the outer core 30 is disposed outside the primary winding 11, while the central core 31 is accommodated inside the secondary bobbin 20.

  Further, on the distal end side of the primary bobbin 10, a bottom hole 41 that is expanded from the boundary port 40 toward the proximal end side with the boundary port 40 having the smallest diameter as a boundary position, and from the boundary port 40 toward the distal end side. A tip hole 42 to be expanded is formed. The high voltage terminal 50 and the resistor 51 are disposed in the bottom hole 41 of the primary bobbin 10, and the bottom hole 41 of the primary bobbin 10 is closed by the resistor 51. Further, the conductor spring SP held by the plug boot 3 is accommodated in the tip hole 42 in a positioned state.

  As shown in the partially enlarged view of FIG. 2, the bottom hole 41 of the primary bobbin 10 has a first part 41a that tapers from the boundary port 40 toward the base end side, and is substantially the same as the maximum inner diameter of the first part 41a. A second portion 41b that extends toward the base end while maintaining the inner diameter and a third portion 41c that has a larger inner diameter than the second portion 41b and extends toward the base end are configured. A ring-shaped mounting surface PT that extends in the radial direction is formed at the boundary position (step portion) between the second portion 41b and the third portion 41c.

  The resistor 51 is integrated with a substantially cylindrical resistor main body 51a and bottomed cylindrical connection caps 51b and 51c that cover both ends of the resistor main body 51a in the axial direction. In addition, it is preferable to employ the resistor 51 that is distributed in the market in an integrated state. Here, the inner diameter dimension of the boundary port 40 of the primary bobbin 10 is set to be substantially the same as the outer diameter dimension of the connection cap 51c. Therefore, in the state where the resistor 51 is mounted (FIGS. 1 and 2), the bottom hole 41 of the primary bobbin 10 is completely closed by press-fitting the connection cap 51c into the boundary port 40.

  The high-voltage terminal 50 includes a main body portion 50a formed in a substantially disk shape, a substantially columnar protrusion 50b provided continuously from the main body portion to the proximal end side, and a cylindrical portion provided continuously from the main body portion 50a to the distal end side. 50c. The inner diameter dimension of the cylindrical portion 50c is formed to be substantially the same as the outer diameter dimension of the connection cap 51b of the resistor 51, thereby forming an accommodation hole HO into which the resistor 51 is press-fitted.

  The outer diameter dimensions of the cylindrical portion 50c and the main body portion 50a of the high-voltage terminal 50 are substantially the same as the outer diameter dimensions of the second portion 41b and the third portion 41c of the bottom hole 41 formed in the primary bobbin 10, respectively. It is formed small. Therefore, the high-voltage terminal 50 is seated and positioned on the placement surface PT of the primary bobbin 10. In this seated state, the bottom surface of the accommodation hole HO of the high-voltage terminal 50 is configured to be positioned substantially in the same plane as the placement surface PT of the primary bobbin 10.

  The high-voltage terminal 50 is inserted into the primary bobbin 10 from the base end side in a state where the resistor 51 is press-fitted. In the illustrated state where the high-voltage terminal 50 is seated, the resistor 51 penetrates the boundary port 40. The connection cap 51c of the resistor 51 is exposed from the tip hole 42. Then, the conductor spring SP mounted from the distal end side of the primary bobbin 10 presses the connection cap 51c, thereby realizing a reliable electrical connection between the secondary coil L2 and the spark plug (not shown).

  FIG. 3 is a drawing showing the shape of the distal end side of the secondary bobbin 20. The secondary bobbin 20 includes a substantially cylindrical bobbin main body 22 around which the secondary winding 21 is wound, and an extension bobbin 23 protruding from the bobbin main body 22 toward the distal end side. It is formed in a substantially cylindrical shape having a smaller diameter than the bobbin main body 22. The inner diameter of the internal hole 24 formed in the extension bobbin 23 is set to be slightly larger than the outer diameter of the protrusion 50b corresponding to the outer diameter of the protrusion 50b of the high-voltage terminal 50.

  Further, an arc groove is formed at the base of the extension bobbin 23 over a half circumference thereof, and a linear groove is formed in the axial direction continuously to the arc groove. An output terminal TR in which the conductive wire is bent and deformed is disposed along the arc groove and the linear groove.

  The output terminal TR is substantially orthogonal to the winding part 61 wound around the arc groove of the extension bobbin 23, the connection part 62 extending in the radial direction from the start end 61a of the winding part 61, and the terminal end 61b of the winding part 61. Thus, the axial direction portion 63 mounted in the linear groove of the extension bobbin 23 is divided into a radial direction portion 64 that is substantially orthogonal to the tip end of the axial direction portion 63 and extends along the distal end surface of the extension bobbin 23. And the connection part 62 is wound and soldered by the high-voltage side lead wire of the secondary winding 21 of the secondary coil L2 (FIG. 3B).

  As shown in FIG. 3C, the radial direction portion 64 of the output terminal TR is arranged slightly inside so as to surely contact the contour circle of the internal hole 24 of the extension bobbin 23. The protrusion 50b of the high-voltage terminal 50 is inserted into the internal hole 24. Since the outer diameter of the protrusion 50b is set substantially the same as the inner diameter of the internal hole 24, the protrusion 50b When inserted into 24, the outer periphery of the protruding portion 50b pushes the radial portion 64 of the output terminal TR outward in the radial direction, thereby realizing reliable electrical contact.

  In the illustrated embodiment, the radial portion 64 is formed in a straight line, but the radial portion 64 is bent into a U shape and the protruding portion 50b of the high voltage terminal 50 is inserted inside the U shape. It is also suitable to make it.

  As described above, in the ignition coil of the present embodiment, the high voltage terminal 50 having the accommodation hole HO and the protrusion 50b, the resistor 51 press-fitted into the accommodation hole HO of the high voltage terminal 50, and the protrusion 50b of the high voltage terminal are inserted. And the secondary bobbin 20 to be configured. Therefore, even if the resistor 51 is accommodated, a short ignition distance from the front end surface of the secondary bobbin 20 to the boundary port 40 of the primary bobbin 10 is sufficient, and a small ignition coil that suppresses the generation of high-frequency noise can be realized.

  Further, at the time of manufacturing, the high-voltage terminal 50 integrated with the resistor 51 is dropped into the bottom hole 41 of the primary bobbin 10, and then the secondary coil L2 is accommodated, so that the high-voltage terminal 50 and the resistor 51 Positioning and closing of the bottom hole 41 are realized, and there is an advantage that the manufacturing process is not complicated.

  As mentioned above, although the Example of this invention was described in detail, the concrete description content does not specifically limit this invention. For example, in the embodiment, the switching element Q is accommodated in the base end portion 1A of the coil case. However, instead of this configuration, the switching element may be disposed outside the coil case. Conversely, in addition to the switching element Q, a detection circuit such as an ion current detection circuit or a control circuit may be arranged at the base end 1A of the coil case.

L1 Primary coil L2 Secondary coil 10 Primary bobbin 11 Primary winding 20 Secondary bobbin 21 Secondary winding TR Output terminal 50b Protrusion 50 High-voltage terminal HO Housing hole SP Conductor spring 51 Resistor 40 Boundary port

Claims (8)

An ignition coil having a coil case in which a primary coil having a primary winding wound around a primary bobbin and a secondary coil having a secondary winding wound around a secondary bobbin are accommodated coaxially. There,
A wire-like output terminal mounted on the tip side of the secondary bobbin and electrically connected to the secondary winding;
A high-voltage terminal having a protruding portion protruding toward the proximal end side and a receiving hole opening on the distal end side, the protruding portion being inserted into the distal end side of the secondary bobbin and electrically connected to the output terminal; ,
A proximal end terminal that is press-fitted into the receiving hole and electrically connected to the high-voltage terminal, and a distal-end terminal electrically connected to the spark plug through a conductive spring material, and
An ignition coil, wherein a tip side of the coil case is closed by the resistor.   The high-voltage terminal includes a main body portion formed in a substantially disc shape, a substantially columnar protruding portion provided continuously from the main body portion to the proximal end side, and a cylindrical portion provided continuously from the main body portion to the distal end side. The ignition coil according to claim 1, wherein the accommodating hole is formed in the cylindrical portion. On the tip side of the coil case,
A boundary opening having a minimum diameter that is blocked by the resistor, a distal end hole that is expanded from the boundary opening toward the distal end side to receive the spring material, and a diameter that is expanded from the boundary opening toward the proximal end side. The ignition coil according to claim 1, wherein a bottom hole is provided.   The bottom hole includes a first part that extends in a tapered shape from the boundary port toward the base end side, a second part that extends to the base end side while maintaining an inner diameter substantially the same as the maximum inner diameter of the first part, The ignition coil according to claim 3, further comprising: a third part having an inner diameter larger than two parts and extending toward the base end side. The inner diameter dimension of the second part of the bottom hole substantially matches the outer diameter dimension of the cylindrical part of the high-voltage terminal, while the inner diameter dimension of the third part of the bottom hole is the outer diameter dimension of the main body part of the high-voltage terminal. Is almost the same as
5. The ignition coil according to claim 4, wherein the high-voltage terminal is configured to be positioned at a stepped portion formed at a boundary position between the second part and the third part of the bottom hole. The resistor is formed in a substantially cylindrical shape as a whole together with the base end side terminal and the tip end side terminal,
4. The ignition coil according to claim 3, wherein a boundary port of the coil case is closed by a distal end side terminal of the resistor. An extension bobbin that protrudes in a small cylindrical shape from the cylindrical body of the secondary bobbin is formed on the tip side of the secondary bobbin,
The output terminal of the secondary coil is configured by bending and deforming a wire material,
A winding part having a start end and a terminal end wound around the outer periphery of the extension part;
An axial portion extending substantially perpendicularly to the winding portion and extending from the end of the winding portion to the tip side; and
A radial portion arranged substantially perpendicularly from the tip of the axial portion and along the distal end surface of the extension, and
The ignition according to any one of claims 1 to 6, wherein the protruding portion of the high-voltage terminal is inserted into the extension bobbin so that the protruding portion and the radial portion are in electrical contact. coil. The output terminal of the secondary coil is provided with a connecting portion extending in the radial direction from the starting end of the winding portion,
The ignition coil according to claim 7, wherein a high-voltage side end of the secondary winding is soldered to the connection portion.