JP2020056362A - Ignition coil for internal combustion engine - Google Patents

Abstract

To provide a technology that facilitates fitting between a terminal of a member forming an ignition coil for an internal combustion engine and a cap.SOLUTION: An ignition coil for an internal combustion engine includes: a coil assembly 120; a lead terminal 121 which has a first end part 121a and a second end part 121b and in which the first end part 121a is electrically connected to the output side of the coil assembly 120; a high voltage terminal 152 having a connection surface 152a electrically connected to the second end part 121b; a case 110 which houses the coil assembly 120, the lead terminal 121, and the high voltage terminal 152; and a resin cap 140 which fits in an end part of the high voltage terminal 152. The cap 140 has an opening 143 which exposes the connection surface 152a.SELECTED DRAWING: Figure 3

Description

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

  In an ignition coil for an internal combustion engine, it is required to reliably transmit a voltage boosted by a coil assembly of the ignition coil for an internal combustion engine to an ignition plug. Therefore, it is desired that the reliability of the electrical connection between the members constituting the ignition coil for the internal combustion engine be high.

  Here, in order to improve the reliability of the electrical connection between the members in the internal combustion engine ignition coil, as described in Patent Document 1, the terminal of the member constituting the internal combustion engine ignition coil is made of metal. A cap may be installed. Fitting is often used for assembling the terminal and the cap.

JP 2017-98462 A

  However, the cap described in Patent Literature 1 is formed of a metal that is difficult to deform. Therefore, in the ignition coil for an internal combustion engine described in Patent Literature 1, the cap may not be fitted to the terminal unless the fitting tolerance in fitting the cap to the terminal is set strictly.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a technique that facilitates fitting of a terminal of a member constituting an internal combustion engine ignition coil with a cap.

  According to one aspect of the present invention, there is provided an ignition coil for an internal combustion engine having a coil assembly, a first end and a second end, and wherein the first end is an output of the coil assembly. A lead terminal electrically connected to the side, a high-voltage terminal having a connection surface electrically connected to the second end, a case accommodating the coil assembly, the lead terminal and the high-voltage terminal, A resin cap fitted to an end of the high voltage terminal, wherein the cap has an opening for exposing the connection surface.

  It is preferable that the bottom surface of the opening is constituted only by the connection surface.

  It is preferable that the inner wall surface forming the opening has an enlarged portion that increases the diameter of the opening from the high voltage terminal side toward the coil assembly side.

  It is preferable that the cap has a flange protruding radially outward of the opening at an end on the coil assembly side.

  The high voltage terminal is a terminal that constitutes a noise resistance.

  In the ignition coil for an internal combustion engine according to the present invention, since the cap is made of resin, it is easier to fit the high-voltage terminal of the member constituting the ignition coil for the internal combustion engine and the cap than in the case where the cap is made of metal. Becomes

  Further, in the present invention in which the bottom surface of the opening is formed only by the connection surface of the high-voltage terminal, the lead terminal is more likely to come into contact with the connection surface than when the bottom surface of the opening is not formed only by the connection surface. As a result, the reliability of the electrical connection between the lead terminal and the high voltage terminal is improved.

  In addition, according to the present invention, when the ignition coil is assembled, the lead terminal and the cap come into contact with each other when the inner wall surface forming the opening has an enlarged diameter portion that increases the diameter of the opening from the high-voltage terminal toward the coil assembly. In this case, the lead terminal can easily move to the bottom surface of the opening where the connection surface of the high-voltage terminal is exposed. As a result, the reliability of the electrical connection between the lead terminal and the high voltage terminal is improved.

  Further, according to the present invention, in which the cap has a flange protruding radially outward of the opening at the end on the coil assembly side, the lead terminal and the cap are easily brought into contact with each other when the ignition coil is assembled. When the lead terminal comes into contact with the cap, the lead terminal is likely to move to the bottom surface of the opening where the connection surface of the high-voltage terminal is exposed, along the shape of the cap. As a result, the reliability of the electrical connection between the lead terminal and the high voltage terminal is improved.

FIG. 1 is a perspective view illustrating an appearance of an ignition coil for an internal combustion engine according to an embodiment. It is a figure showing the sectional view of the ignition coil for internal-combustion engines concerning an embodiment. It is a figure for explaining the cap concerning an embodiment.

<Appearance of ignition coil for internal combustion engine>
FIG. 1 is a perspective view showing an appearance of an ignition coil 100 for an internal combustion engine according to the embodiment. As shown in FIG. 1, a case 110 of an internal combustion engine ignition coil 100 (hereinafter, simply referred to as “ignition coil 100”) includes a connector section 111, a fixing section 112, a housing section 113, and a high-pressure section 114. I have.

  A connector of a wire harness (not shown) is connected to the connector section 111. A plurality of connector terminals 111a are provided inside the connector unit 111, and the connector terminals 111a are connected to electronic devices such as an ECU (Engine Control Unit) via a wire harness. Thus, the input voltage and the signal from the ECU are input to the ignition coil 100.

  The fixing portion 112 has a through hole into which a fixing bolt can be inserted. By fixing the fixing bolt to the engine block with the fixing bolt inserted into the through hole of the fixing portion 112, the ignition coil 100 is fixed to the engine block.

  The housing section 113 and the high-pressure section 114 house other members (parts) constituting the ignition coil 100 described later. Further, the voltage boosted by the ignition coil 100 based on the input voltage or signal input from the connector terminal 111a is applied from the high voltage unit 114 to an ignition plug (not shown).

<Structure of ignition coil>
FIG. 2 is a diagram illustrating a cross section of the ignition coil 100 according to the embodiment. As shown in FIG. 2, a coil assembly 120, a lead terminal 121, a noise resistance 150, a cap 140, and a filling resin 130 are accommodated in the accommodating portion 113 and the high voltage portion 114. In addition, as shown in FIG. 2, the spaces inside the housing unit 113 and the high-pressure unit 114 are connected.

  The coil assembly 120 includes a primary coil 120a, a secondary coil 120b, and the like, and is fixed in the housing 113. More specifically, the coil assembly 120 is positioned and fixed by the side surface and the bottom surface inside the housing portion 113. The input terminal of the coil assembly 120 is connected to the connector terminal 111a. The coil assembly 120 induces a high voltage in the secondary coil 120b by cutting off the power supply to the primary coil 120a based on a signal from the ECU. Then, the coil assembly 120 outputs the voltage induced by the secondary coil 120b from an output terminal of the coil assembly 120.

  The lead terminal 121 supplies the voltage applied from the output terminal of the coil assembly 120 to the noise resistance 150. The lead terminal 121 has a first end 121a and a second end 121b. The first end 121a is connected to an output terminal of the coil assembly 120. Then, in the assembly process of the ignition coil 100, the second end 121 b of the lead terminal 121 comes into contact with the noise resistance 150 by inserting the coil assembly 120 to which the lead terminal 121 is connected into the housing 113. Thereby, the coil assembly 120 and the noise resistance 150 are electrically connected via the lead terminals 121.

  The shape of the second end 121b of the lead terminal 121 is not limited to the shape shown in FIG. The second end 121b may be bent at an angle different from the angle shown in FIG. 2 or may not be bent.

  The noise resistance 150 removes noise in the ignition coil 100. The noise resistance 150 includes a first high-voltage terminal 152, a resistance member 151, and a second high-voltage terminal 153. Then, as shown in FIG. 2, the noise resistance 150 is fixed in the high-voltage unit 114 such that the first high-voltage terminal 152 is located near the boundary between the housing unit 113 and the high-voltage unit 114. More specifically, in the assembly process of the ignition coil 100, the jig is positioned and the noise resistance 150 is fitted to the case 100. Thereafter, the first high-voltage terminal 152 and the lead terminal 121 are connected by inserting the coil assembly 120 to which the lead terminal 121 is connected into the housing 113. The voltage applied to the first high-voltage terminal 152 is applied via the resistance member 151 from the second high-voltage terminal 153 to the side of the ignition plug (the device following the ignition coil 100).

  The cap 140 is fitted to the noise resistance 150. The cap 140 will be described later in detail. The gap formed in the housing 113 and the high-pressure part 114 is filled with the filling resin 130.

<About the cap>
FIG. 3 is a diagram for explaining the cap 140 according to the embodiment. As shown in FIG. 3, the cap 140 is fitted to an end of the first high-voltage terminal 152 which is an input terminal of the noise resistance 150.

  In addition, as shown in FIG. 3, the cap 140 is provided with an opening 143. The opening 143 exposes a connection surface 152 a that is electrically connected to the lead terminal 121 at the first high-voltage terminal 152. More specifically, when the cap 140 is fitted to the first high-voltage terminal 152, the connection surface 152 a of the first high-voltage terminal 152 is located on the bottom surface of the opening 143. Then, when the coil assembly 120 connected to the lead terminal 121 is inserted into the accommodating portion 113 in a state where the cap 140 is fitted to the first high-voltage terminal 152, as shown in FIG. Inside (in a state of being surrounded by the inner wall surface 145 forming the opening 143), the second end 121b of the lead terminal 121 and the connection surface 152a of the first high-voltage terminal 152 come into contact with each other. Thereby, the lead terminal 121 and the noise resistance 150 are electrically connected.

  The cap 140 is formed of a resin material. More specifically, the cap 140 is formed of a thermoplastic plastic such as engineering plastic or super engineering plastic. Examples include polybutylene terephthalate (PBT), polyphenylene sulfide (PPS), and polyphenylene ether (PPE). Generally, resin materials such as thermoplastics are more likely to be elastically deformed than metal materials such as aluminum. Therefore, for example, even when the diameter of the first high-voltage terminal 152 is larger than the diameter of the opening hole 143 of the cap 140, the resin cap 140 according to the present embodiment is smaller than the metal cap. It easily deforms according to the diameter of one high-voltage terminal 152.

  In the ignition coil 100 according to the present embodiment, since the cap 140 is made of resin, the fitting (the first high-voltage terminal 152) of the ignition coil 100 and the cap 140 are more fitted than when the cap is made of metal. Alignment becomes easy.

  In addition, the lead terminal 121 and the first high-voltage terminal 152 may not be in contact with each other due to a dimensional tolerance of components constituting the ignition coil 100 or a tolerance at the time of assembly. For example, when assembling the ignition coil 100 (more specifically, when inserting the coil assembly 120 into the housing portion 113), the second end 121b of the lead terminal 121 moves from the inside of the connection surface 152a to the outside of the connection surface 152a. May move toward. However, in ignition coil 100 according to the present embodiment, connection surface 152a is located on the bottom surface of opening 143. Therefore, when the second end 121b largely moves toward the outside of the connection surface 152a, the second end 121b comes into contact with the inner wall surface 145 forming the opening 143. That is, the second end 121b is restricted from being separated from the connection surface 152a by the inner wall surface 145. In other words, the cap 140 has a fitting portion 142 fitted to the first high-voltage terminal 152 and a locking portion 144 that regulates the movement of the lead terminal 121 (the second end 121b) by the inner wall surface 145. ing. In the ignition coil 100 according to the present embodiment, since the cap 140 has the locking portion 144, it is difficult for the second end 121b and the connection surface 152a to separate. As a result, the reliability of the electrical connection between the lead terminal 121 and the first high voltage terminal 152 is improved.

  Note that, in the present embodiment, as shown in FIG. 3, the bottom surface of the opening 143 is constituted only by the connection surface 152a of the first high-voltage terminal 152. However, the bottom surface of the opening 143 does not need to be constituted only by the connection surface 152a. For example, there is a case where the hole diameter of the opening hole 143 is not uniform, and the hole diameter of the locking portion 144 is larger than the hole diameter of the fitting portion 142. In this case, the outer edge portion of the bottom surface of the opening 143 is formed by the cap 140. However, the higher the proportion of the connection surface 152a in the bottom surface of the opening 143, the higher the possibility that the lead terminal 121 contacts the connection surface 152a.

  In the ignition coil 100 according to the present embodiment, since the bottom surface of the opening 143 is formed only by the connection surface 152a of the high-voltage terminal (first high-voltage terminal 152), the bottom surface of the opening 143 is formed only by the connection surface 152a. The lead terminal 121 is more likely to come into contact with the connection surface 152a as compared with a case where it is not configured. As a result, the reliability of the electrical connection between the lead terminal 121 and the high voltage terminal (first high voltage terminal 152) is improved.

  In the present embodiment, as shown in FIG. 3, the entire connection surface 152a of the first high-voltage terminal 152 is exposed from the opening 143, but the portion exposed from the opening 143 is a connection surface. 152a. The higher the exposed area of the connection surface 152a, the higher the possibility that the lead terminal 121 and the connection surface 152a come into contact with each other. In the present embodiment, since the opening 143 exposes all of the connection surface 152a of the first high-voltage terminal 152, the lead terminal 121 easily contacts the connection surface 152a. As a result, the reliability of the electrical connection between the lead terminal 121 and the high voltage terminal (first high voltage terminal 152) is improved.

<About the shape of the locking part>
The cap 140 is opened from the first high-voltage terminal 152 side to the coil assembly 120 side on the inner wall surface 145 of the locking portion 144 (that is, the end of the cap 140 on the side of the coil assembly 120) which forms the opening hole 143. The hole 143 may have an enlarged portion 146 for increasing the diameter. Here, the enlarged diameter portion 146 may be formed on the entire inner wall surface 145, or may be formed on a part of the inner wall surface 145.

  As an example of the shape of the enlarged diameter portion 146, as shown in FIG. 3, the end of the inner wall surface 145 on the coil assembly 120 side may be rounded (rounded). When assembling the ignition coil 100 (more specifically, when the coil assembly 120 is inserted into the accommodating portion 113), when the second end 121b of the lead terminal 121 contacts such an enlarged diameter portion 146, In addition, there is a high possibility that the lead terminal 121 is guided to the bottom surface of the opening 143 along the shape of the enlarged diameter portion 146.

  In the ignition coil 100 according to the present embodiment, the inner wall surface 145 forming the opening 143 increases the diameter of the opening 143 from the high voltage terminal (first high voltage terminal 152) side toward the coil assembly 120 side. Since the terminal 146 has the portion 146, when the lead terminal 121 comes into contact with the cap 140 at the time of assembling the ignition coil 100, the connection surface 152a of the high-voltage terminal (first high-voltage terminal 152) is exposed. It is easy to move to the bottom surface of the opening 143. As a result, the reliability of the electrical connection between the lead terminal 121 and the high voltage terminal (first high voltage terminal 152) can be improved.

  Note that the shape of the enlarged diameter portion 146 is not limited to the shape shown in FIG. For example, in the enlarged diameter portion 146, the entire inner wall surface 145 may be tapered, and the diameter of the opening 143 may be increased from the first high-voltage terminal 152 toward the coil assembly 120. In this case, the lead terminal 121 that has come into contact with the inner wall surface 145 (that is, the enlarged diameter portion 146) at the time of assembling the ignition coil 100 moves to the bottom surface of the opening 143 along the tapered shape of the inner wall surface 145. As a result, the reliability of the electrical connection between the lead terminal 121 and the high voltage terminal (first high voltage terminal 152) can be improved.

  Further, the enlarged diameter portion 146 may be a slope provided on a part of the inner wall surface 145. For example, when a portion of the inner wall surface 145 that is likely to be in contact with the lead terminal 121 is known in advance, only the portion that is likely to be in contact with the lead terminal 121 is inclined such that the lead terminal 121 is guided to the bottom surface of the opening 143. It may be provided. When assembling the ignition coil 100, the lead terminal 121 that has contacted such an inclination (the enlarged diameter portion 146) moves to the bottom surface of the opening 143 along the inclination. As described above, by providing the enlarged diameter portion 146 at a portion of the inner wall surface 145 that is likely to come into contact with the lead terminal 121, the reliability of the electrical connection between the lead terminal 121 and the high-voltage terminal (first high-voltage terminal 152) is improved. Can be improved.

  In addition, the cap 140 may have a flange portion 141 protruding radially outward of the opening 143 at the locking portion 144 (that is, the end on the coil assembly 120 side). The larger the size of the protrusion of the flange portion 141, the more the lead terminal 121 may come into contact with the cap 140 at the time of assembling the ignition coil 100 (more specifically, when the coil assembly 120 is inserted into the housing portion 113). Will be higher.

  In the ignition coil 100 according to the present embodiment, the cap 140 has the flange 141 projecting outward in the radial direction of the opening 143 at the end on the coil assembly 120 side. The lead terminals 121 and the cap 140 are easily brought into contact with each other. When the lead terminal 121 and the cap 140 come into contact with each other, the lead terminal 121 is formed on the bottom surface of the opening 143 where the connection surface 152a of the high-voltage terminal (first high-voltage terminal 152) is exposed along the shape of the cap 140. More likely to move. As a result, the reliability of the electrical connection between the lead terminal 121 and the high voltage terminal (first high voltage terminal 152) is improved.

  Note that the protrusion dimensions of the flange portion 141 need not be the same in all directions. For example, the protrusion dimension of the flange 141 may change depending on the direction. Further, there may be a direction in which the flange 141 is not provided.

<Modification>
In the above-described embodiment, the cap 140 is fitted to the first high-voltage terminal 152 that is the terminal of the noise resistance 150. However, the cap 140 may be fitted to a terminal of a member other than the noise resistance 150. For example, when the noise resistance 150 is not provided in the ignition coil 100 and the lead terminal 121 is connected to the output terminal of the ignition coil 100, the cap 140 may be fitted to the output terminal.

100: ignition coil 110 for internal combustion engine: case 111: connector part 112: fixing part 113: housing part 114: high voltage part 120: coil assembly 121: lead terminal 121a: first end part 121b: second end part 130: filling resin 140: Cap 141: Flange 142: Fitting part 143: Opening hole 144: Locking part 145: Inner wall surface 146: Enlarged diameter part 150: Anti-noise resistance 151: Resistance member 152: First high voltage terminal 152a: Connection surface 153 : Second high voltage terminal

Claims (5)

A coil assembly;
A lead terminal having a first end and a second end, and wherein the first end is electrically connected to an output side of the coil assembly;
A high-voltage terminal having a connection surface electrically connected to the second end,
A case accommodating the coil assembly, the lead terminal, and the high-voltage terminal;
A resin cap fitted to the end of the high-voltage terminal,
The ignition coil for an internal combustion engine, wherein the cap has an opening that exposes the connection surface.   The ignition coil for an internal combustion engine according to claim 1, wherein a bottom surface of the opening is formed only by the connection surface.   The ignition coil for an internal combustion engine according to claim 1 or 2, wherein the inner wall surface forming the opening has an enlarged diameter portion that increases the diameter of the opening from the high voltage terminal side toward the coil assembly.   The ignition coil for an internal combustion engine according to any one of claims 1 to 3, wherein the cap has a flange protruding radially outward of the opening at an end on the coil assembly side. .   The ignition coil for an internal combustion engine according to any one of claims 1 to 4, wherein the high-voltage terminal is a terminal constituting a noise resistance.

Images