JP2003229317A - Internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To fully satisfy insulation and a high output in an ignition coil for an internal combustion engine supplying a high voltage to a spark plug under a strictly limited space. <P>SOLUTION: This engine provides an iron core and a secondary coil winding a secondary conductive wire to a secondary bobbin coaxially with the iron core and a primary coil winding a primary conductive wire to a primary bobbin. In is characterized in that the engine makes narrower the channel width of a separating width channel of the secondary bobbin, which is the channel width of a bobbin separating width channel of the low-voltage side and the high- voltage side of the secondary bobbin positioning at both ends rather than the center of the secondary bobbin, in an ignition coil for the internal combustion engine of a cylinder type accommodated inside a plug hole connected directly to the spark plug. <P>COPYRIGHT: (C)2003,JPO

Description

Description: BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to an ignition coil for an internal combustion engine which is mounted in each plug hole of an engine and is used directly connected to each ignition plug. In particular, it relates to a secondary bobbin. 2. Description of the Related Art In recent years, ignition coils for independent internal combustion engines have
Introduced into the plug hole of the engine and directly connected to each ignition plug, at least a part of the coil part is introduced and installed in the plug hole, and the coil part is inserted into the plug hole, so that an elongated cylindrical coil A central iron core, a secondary coil, a primary coil, and an exterior iron core are provided inside the case. FIGS. 3 and 4 show an ignition coil 1 for directly supplying a high voltage to an ignition plug to which the prior art is applied. Wound around a central iron core 70 made of a magnetic steel plate such as a silicon steel plate, and a secondary bobbin 21 on the outer periphery of the central iron core 70 in which the width of the dividing groove 23 is substantially uniform from the low-pressure portion to the high-pressure portion. A secondary coil 20 to be turned, a primary coil 10 wound around a primary bobbin 11 arranged coaxially with the secondary coil 20, an outer core 60 outside the coils, a case 30 And an insulating material is injected into the case 30 and cured to form a coil portion. Further, a primary current input section 31 electrically connected to the primary coil 10 and the secondary coil 20 is provided above the coil section, and in some cases, the primary current is turned on.
The power transistor 80 to be turned off is also stored. A high-pressure tower section 32 is provided at a lower portion.
2 has a secondary high voltage terminal 22 and is electrically coupled to a spring 40 for transmitting a high voltage generated by the secondary coil 20 to a spark plug (not shown). High pressure tower 3
2 is provided with a protector 50 for preventing a high voltage from leaking to the metal part of the plug hole, and is closely fitted to a spark plug (not shown). The operation of the above-described ignition coil for an internal combustion engine will be described. The current input from the primary current input unit 31 generates a magnetic flux through the primary coil 10, makes it easier to pass the magnetic flux by the center iron core 70 and the armature iron core 60, and interrupts the current at the ignition timing by the power transistor 80. As a result, a high voltage is generated in the secondary coil 20. The high voltage generated by the secondary coil 20 passes through the secondary high voltage terminal 22 attached to the high voltage tower 32, and is applied to the spark plug via the spring 40. [0006] While a high-performance, trouble-free and low-priced vehicle is desired, ignition coils are required to have higher output, longer life, and lower cost. Because it is housed in the plug hole, the space of the coil part is very narrow, and it has been an issue how to supply an ignition coil for an internal combustion engine with high output and excellent insulation in this limited space. . It is considered that the center iron core 70 is insulated at its periphery and is at an intermediate potential between the low voltage side and the high voltage side of the secondary coil under the influence of the electric field of the secondary coil. For example, if the low voltage side of the secondary coil is 0 V and the high voltage side is -30 kV, the intermediate potential of the central iron core is expected to be -15 kV. Therefore, a potential of 15 kV difference is generated between the secondary coil and the central iron core between the high voltage side of the secondary coil and the low voltage side of the secondary coil as well as the low voltage side of the secondary coil. Generates a potential difference. In addition, since the center iron core is arranged in the secondary bobbin, the center position of the inner diameter of the secondary bobbin and the center position of the center iron core are shifted, so that particularly the center iron core between the center iron core and the secondary bobbin. Thermal stress concentration occurs at both ends. For this reason, cracks occur at both ends of the secondary bobbin due to the above-mentioned concentration of thermal stress, which causes a decrease in insulation. SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and in an ignition coil for an internal combustion engine for supplying a high voltage to an ignition plug whose space is severely restricted, the stress is equalized and the insulation and the high output are sufficiently achieved. The purpose is to satisfy. According to the present invention, there is provided an ignition coil for an internal combustion engine in which a secondary conductor is wound around a secondary bobbin coaxially with the iron core. A secondary coil,
A primary coil in which a primary conductor is wound around a primary bobbin,
In the cylindrical internal combustion engine ignition coil directly connected to the ignition plug and housed in the plug hole, the secondary bobbin divided width groove of the secondary bobbin has a groove width located at both ends of the secondary bobbin rather than a center portion thereof. The width of the bobbin division width grooves on the low pressure side and the secondary bobbin high pressure side is reduced. When the above means is used, the width of the divided width groove of the secondary bobbin is set at both ends of the secondary bobbin rather than at the center thereof.
The strength of both ends of the secondary bobbin can be improved by reducing the width of the bobbin division width grooves on the low pressure side of the secondary bobbin and the high pressure side of the secondary bobbin. Since the width of the groove can be widened, it is possible to provide an ignition coil for an internal combustion engine having equalized stress, ensuring insulation, and having a long life. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an ignition coil for an internal combustion engine according to an embodiment of the present invention will be described in detail with reference to FIG. 1 and FIG. The ignition coil 1 for an internal combustion engine shown in FIG.
A central iron core 70 made of a magnetic steel plate such as a silicon steel plate, a secondary coil 201 wound around a secondary bobbin 211 on the outer periphery of the central iron core 70, and arranged coaxially with the secondary coil 201. A primary coil 10 wound around the primary bobbin 11 provided, an outer core 60 outside the coils, and a case 30. An insulating material is injected into the case 30 and cured to form a coil portion. Has formed. Further, a power transistor for electrically turning on and off the primary current is provided on the upper part of the coil section, and a primary current input section 31 electrically connected to the primary coil 10 and the secondary coil 201 is provided. 80 is also stored. A high-pressure tower section 32 is provided at a lower portion. The high-pressure tower section 32 has a secondary high-voltage terminal 22 and is electrically coupled to a spring 40 that transmits a high voltage generated in the secondary coil 201 to a spark plug (not shown). Have been. Further, the high-pressure tower portion 32 is provided with a protector 50 so that a high voltage does not leak to the metal portion of the plug hole 90, and is closely fitted to an ignition plug (not shown). Regarding the secondary coil 201 shown in FIG.
The secondary coil 201 sets the groove width of the dividing groove 23 such that the groove width of the bobbin dividing groove 23 on the secondary bobbin 211 low pressure side and the secondary bobbin 211 high pressure side located at both ends of the secondary bobbin 211 is larger than the central part thereof. It is narrow. This is because, when compared with the secondary coil 20 in which the groove width of the dividing groove 23 is substantially uniform from the low-pressure portion to the high-pressure portion, the secondary bobbin 211 located at both ends of the conventional secondary bobbin 21 on the low pressure side and The groove width of the bobbin dividing groove 23 on the high pressure side of the secondary bobbin 211 is narrow, and the number of the dividing flanges 24 at the central portion of the secondary bobbin 211 is reduced to increase the groove width of the bobbin dividing groove 23. In the present embodiment, the bobbin strength at the center of the secondary coil, which is less affected by the potential difference from the central iron core 70, of the secondary bobbin 211 may be reduced, as described above.
Therefore, the width of the dividing groove 23 can be maximized.
4 can be reduced. Further, the number of windings of the secondary coil can be increased by an amount corresponding to the reduction of the split collar 24, and the output can be improved. According to the ignition coil for an internal combustion engine of the present invention,
The secondary bobbin is formed by reducing the groove width of the secondary bobbin dividing groove on the secondary bobbin low pressure side and the secondary bobbin high pressure side located at both ends of the secondary bobbin rather than the central portion thereof. By increasing the strength at both ends and increasing the width of the dividing groove at the center, the number of secondary windings can be equalized or increased, and the insulation and high output can be sufficiently satisfied.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectional view of an ignition coil for an internal combustion engine to which the technology of the present invention is applied; FIG. 2 is a longitudinal sectional view of a secondary coil of the present invention; FIG. FIG. 4 is a longitudinal sectional view of an ignition coil. FIG. 4 is a longitudinal sectional view of a conventional secondary coil. [Description of References] In the drawings, the same reference numerals indicate the same or corresponding parts. DESCRIPTION OF SYMBOLS 1 Ignition coil 10 for internal combustion engines Primary coil 11 Primary bobbin 20, 201 Secondary coil 21, 211 Secondary bobbin 22 Secondary high voltage terminal 23 Dividing groove 24 Dividing flange 30 Case 31 Primary current input section 32 High voltage tower section 40 Spring 50 Protector 60 Exterior iron core 70 Center iron core 71 Buffer material 72 Protective tape 80 Power transistor

Claims (1)

Claims 1. An iron core, a secondary coil having a secondary bobbin wound around a secondary bobbin coaxially with the iron core, and a primary coil having a primary wire wound around a primary bobbin. A cylindrical bobbin, which is directly connected to the spark plug and housed in the plug hole, wherein the width of the divided groove of the secondary bobbin is located at both ends of the secondary bobbin rather than at the center thereof. An ignition coil for an internal combustion engine, characterized in that the widths of the bobbin dividing grooves on the secondary bobbin low pressure side and the secondary bobbin high pressure side are reduced.