JPH06349651A - Ignition coil used for internal combustion engine - Google Patents

Abstract

PURPOSE: To obtain an ignition coil provided with reproducible output characteristics by a method, wherein a notch is provided on the region of overcoat cores facing the edge face of both end parts, and both end parts are at least partially thrusted into the notch. CONSTITUTION: A core 11 of this ignition coil is composed of a frame-like closed overcoat core 12 and two rod-like center leg parts 13 which are symmetrically arranged in the overcoat core 12. Further, a primary coil and a secondary coil are supported by the center leg parts 13 on a center part 14 in a coaxial arrangement relation. The edge face of both edge parts 17 is separated from the overcoat core 12 by caps 18, formed by low permeability material. The region of the overcoat core 12, which faces the edge face of both edge parts 17, has a notch 24, and both edge parts 17 are partially thrusted into the notch 24.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ignition coil used in an internal combustion engine, which is provided with a core made of a material having a high magnetic permeability, and one portion of the core is at least substantially closed. The other part of the core is formed as a central leg that traverses the mantle core, the central part of the central leg supporting the primary coil and the secondary coil being the central leg. Has a cross-section smaller than the cross-section of one of its two ends, the end faces of which are separated from the mantle core by at least one gap with a material of low magnetic permeability. Regarding the type of existing.

[0002]

2. Description of the Prior Art Ignition coils of this type are known from DE-A 1 259 990. The ferromagnetic core of this known ignition coil is formed as a central magnetic core, which is formed as a central magnet core and is arranged inside the primary coil, and a magnetic core for the return path, which surrounds the central leg. Made of cloak core and. An air gap is provided between the ends of the central leg and the outer core, which face each other as a flat surface. The air gap can be filled with permanent magnets to bias magnetize the core. Taking into account manufacturing tolerances for cores constructed from layered lamellas, it is difficult to adhere to precisely defined values for the width of such air gaps.

However, the width of the air gap affects the overall function of the ignition coil. Because that
This width decisively defines the magnetic energy of the ignition coil. As the width of the air gap changes during the manufacturing process, the ignition coil has different output characteristics, so under these circumstances, a cheap supply of mass produced ignition coil with reproducible output characteristics is guaranteed. Can't do it.

[0004]

SUMMARY OF THE INVENTION The object of the present invention is to improve an ignition coil of the type mentioned at the outset so that ignition coils with reproducible output characteristics can be mass-produced inexpensively. is there.

[0005]

In order to solve this problem, in the structure of the present invention, the region of the outer core facing the end faces of both end portions has a notch, and the notch has both end portions. Was at least partially inrush.

[0006]

With the structure of the present invention, the inconveniences described above can be sufficiently avoided. In the configuration of the present invention, the ignition coil has the notch in each region of the outer core facing the end faces of the both ends of the central leg portion, and these notches,
The ends of the central legs project at least partially.

By providing such a shape, the length of the air gap and the transition surface of the magnetic force line between the outer core and the end portion of the central leg portion are increased. Therefore, assuming that the magnetic circuits have the same reluctance, the air gap according to the present invention can be expanded over the conventional configuration of the air gap. If the manufacturing tolerance of the width of the air gap is specified to be constant, the adverse effect of the manufacturing tolerance will be reduced if the air gap is widened, and this reduces the functional value of the ignition coil product by mass production. Renewability is improved.

Furthermore, the energy storage capacity of the ignition coil can be enhanced by the larger air gap.

Claims 2 and below describe advantageous measures for implementing the invention.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A core 11 of an ignition coil used in an internal combustion engine, which is shown in a schematic form, includes an outer core 12 closed in a frame shape, and a rod-shaped basic core symmetrically arranged in the outer core 12. It is composed of a central leg portion 13 having a shape. In a known manner, this core 11 is made of a highly magnetically permeable material and has the form of stamped and laminated iron sheets. Furthermore, the central leg 13
Supports a primary coil and a secondary coil (not shown) in the central portion 14 in a coaxial arrangement.

Following the central portion 14, a longitudinal axis 16
There are ends 17 on either side when viewed in the direction of, and these ends have an increased cross-section with respect to the central portion 14. This cross section shows a pole piece-like extension of the ends 17 with respect to the central portion 14, which extends symmetrically with respect to the longitudinal axis 16.

The end faces of both ends 17 are separated from the outer core 12 by respective caps 18 made of a low magnetic permeability material. This low magnetic permeability material is air in this example. Alternatively, however, a non-conductive permanent magnet may be inserted in this gap 18 to bias magnetize the core 11.

The outer core 12 of this embodiment can be divided into two lateral legs 19 or transverse yokes 21 facing each other in parallel. These lateral legs and the lateral yoke are arranged integrally so as to form a square, the two lateral yokes 21 and the central leg 13 all having the same height. ing. These transverse yokes 21 extend parallel to the longitudinal axis 16 and the lateral legs 19 extend at right angles to the longitudinal axis 16. For this purpose, projections 22 are attached to the two diametrically opposite corners formed at the connection between the respective lateral yoke 21 and the lateral leg 19. These protrusions have respective holes 23 for fixing the core 11 to the ignition coil (not shown).

Lateral leg portions 19 facing the end faces of both end portions 17
Each region has a notch 24. In this case, the gap 18 has a partial width over its length extending so as to have an optimum width such that the manufacturing tolerances influence the functional value of the ignition coil as little as possible. The end 17 protruding into the notch 24 is separated from the side leg 19.

In this embodiment, each end 17 has on its end face a first section 26 extending into a notch 24. This first section is oriented perpendicular to the longitudinal axis 16 and is divided in half by this longitudinal axis. Continuing from both ends of this first section 26, diagonal chamfers 27 are provided on both sides. These beveled chamfers are inclined with respect to the first section 26 at an interior angle of approximately 150 °. Such beveled chamfers 27 extending symmetrically with respect to the longitudinal axis 16 are such that these beveled chamfers at the end opposite the first section 26 project slightly from the cutout 24. Has been formed. Following these ends, a second section 28 is provided so as to make an interior angle of approximately 40 ° with the bevelled chamfer 27. These second sections are arcuately shaped in their end contours and continue to the respective longitudinally outwardly restricted portions of the central portion 14.

Optionally, the end faces of these ends 17 are, for example, the first section 26 and the bevelled chamfer 27 together,
It may be machined to have a curved profile. In this case, while maintaining a constant width of the gap 18,
The cutout 24 has a corresponding counter-formed part.

Further optionally, the mantle core 12 may have an annular cross section and the central leg 13 may be arranged within a diameter.

In order to obtain the longest possible gap 18 between the respective end 17 and the outer core 12, the depth of the cutout 24 is such that in the region of the outer core 12 facing the first section 26. Side legs 19 of mantle core 12
Extends to almost 70% of its width. Such a constricted part of the cross section of the mantle core 12 is made by the current flowing through the coil arranged so as to surround the central part 14 of the core 1.
The magnetic flux generated in 1 has no significant effect. This is because the magnetic flux in the central portion 14 is branched at one end 17 to form two magnetic flux circuits that face each other, and further, through the diagonal chamfered portion 27, both sides of one side leg portion 19 are supported. An arcuate transition to the part, whereby it passes through the other lateral leg 19 and again to the other end 17
This is because it enters the central portion 14 through the two beveled chamfered portions 27 provided on the. By such a magnetic flux guide performed through the beveled chamfer 27, the mantle core 12 is
It is guaranteed that the entire cross section of is available for magnetic flux. The gap between the central leg 13 and the outer core 12 is
The central leg portion 13 protruding into the cutout 24 of the outer core 12.
Is increased by the end portion 17 of the core 11, particularly when the magnetic resistance of the core 11 is determined, which is determined by the surface extending along the gap 18 and the width of the gap 18,
The width of the gap 18 can be increased. As a result, it is possible to manufacture an ignition coil which has a small variation in functional value during mass production and has a high energy storage capacity.

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of a core of an ignition coil according to the present invention.

[Explanation of symbols]

11 cores, 12 mantle cores, 13 central legs,
14 central part, 16 longitudinal axis, 17 end, 18 gap, 19 lateral leg, 21 lateral yoke, 22 protrusion, 23 hole, 24 notch, 26 first section, 27 diagonal chamfer,
28 Second division

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Dieter Betz Germany Feihingen Goethestraße 23-4 (72) Inventor Volgang Gede Schweaverdingen Peter-von-Koblenz-Schutlasse 68 (72) Inventor Armin Kunz Germany Rütesheim Schipselstraße 105

Claims (8)

[Claims] 1. An ignition coil for use in an internal combustion engine, comprising a core (11) made of a highly magnetically permeable material, and one portion of the core being at least substantially closed to a mantle core (12). ), The other part of the core is formed by a central leg (1) that traverses the mantle core (12).
3), the central part (14) of the central leg (13) supporting the primary coil and the secondary coil is
It has a cross-section smaller than the cross-section of one of the two ends (17) of the central leg (13), the end faces of which are at least one with a material of low magnetic permeability. In the type separated from the outer core (12) by the gap (18), the region of the outer core (12) facing the end faces of both ends (17) has a notch (24).
An ignition coil for use in an internal combustion engine, characterized in that both ends (17) of the notch (24) project at least partially. 2. The gap (18) is formed as an air gap and the longitudinal axis (1) of the central leg (13).
Ignition coil according to claim 1, arranged symmetrically with respect to 6). 3. Ignition coil according to claim 2, wherein the width of the gap (18) is substantially constant. 4. The gap (18) is arranged partly perpendicular to the longitudinal axis (16) of the central leg (13) and partly at a different angle. The ignition coil as claimed in claim 3, wherein 5. Ignition coil according to claim 4, wherein the gap (18) extends curvedly. 6. Ignition coil according to claim 1, wherein a permanent magnet is arranged in the gap (18). 7. The ignition coil according to claim 1, wherein the outer core (12) is formed in a frame shape. 8. The ignition coil according to claim 1, wherein the outer core has an annular cross section.