JPH0812827B2 - Ignition coil for internal combustion engine - Google Patents

Description

TECHNICAL FIELD The present invention relates to an ignition coil for an internal combustion engine in which a permanent magnet is arranged in a magnetic circuit.

[Prior Art] In recent years, there is an ignition coil in which a permanent magnet is arranged in a magnetic circuit of a core for the purpose of downsizing and high performance of a product (US Pat. No. 4,658,799).

As an example of an ignition coil that uses this permanent magnet, a T-shaped first core around which a primary coil and a secondary coil are wound around an outer periphery, and a square-shaped second core that forms a magnetic path with the first core And the first core is arranged inside the second core, and the permanent magnet is arranged in the air gap formed between the end surface of the first core and the inner peripheral surface of the second core. Proposed.

[Problems to be Solved by the Invention] However, in the structure in which the T-shaped first core is arranged in the square shaped second core as described above, the core dimensions (the length of the first core and the inner circumference of the second core are Due to the variation in the width) and the variation in the thickness dimension of the permanent magnet, a gap is generated somewhere on the joint surface.

According to the measurement results of the inventors of the present application, when a gap is generated on the air gap side (that is, between the other end surface of the first core and the permanent magnet or between the permanent magnet and the second core), the ignition coil It was confirmed that there was little effect on the performance, but when there was a gap between the one end surface of the first core and the second core, the variation in performance was large.

The present invention has been made based on the above circumstances, and an object thereof is to fix a gap at each joint surface caused by a variation in a core dimension and a thickness dimension of a permanent magnet on the air gap side to reduce or vary performance. An object of the present invention is to provide an ignition coil for an internal combustion engine that has less influence on the above.

[Means for Solving the Problems] The present invention adopts the following configurations in order to achieve the above object.

In Claim 1, a primary coil and a secondary coil, a first core that penetrates the primary coil and the secondary coil, one end of the first core is in contact with one end of the first core, and the other end is through an air gap. And a second core that faces the other end of the first core and forms a closed magnetic path that includes the air gap, and is disposed in the air gap so as to repel magnetic flux generated by energizing the primary coil. And a plate-shaped permanent magnet, which is interposed between the first core and the second core in the air gap portion, and presses one end of the first core and one end of the second core. A gap forming member that forms the air gap between the other end of the first core and the other end of the second core in a state of being brought into contact with each other.

According to a second aspect of the present invention, in the ignition coil for an internal combustion engine according to the first aspect, the gap forming member is a resin member integrally formed with at least one of the first core and the second core, Between the first core and the second core on the air gap side, it is interposed so as to separate the other end of the first core and the other end of the second core. Characterize.

According to a third aspect of the present invention, in the internal combustion engine ignition coil according to the first or second aspect, the first core has a larger area in which the other end faces the second core than the one end. It is characterized by being

According to a fourth aspect of the present invention, in the ignition coil for an internal combustion engine according to any one of the first to third aspects, the second core is provided with the one end and the other end in parallel, and the first core is provided. Is disposed in a press-fit state between the one end and the other end of the second core via the gap forming member.

[Operation] According to the present invention, with the gap forming member, the one end of the first core is pressed against the one end of the second core to be in contact with the other end of the first core and the other end of the second core. An air gap is formed between them. As a result, the gap between the first core and the second core, which is caused by variations in the core size and the thickness of the permanent magnet, is located on the air gap side (that is, between the other end surface of the first core and the permanent magnet, or It is fixed between the permanent magnet and the other end surface of the second core).

EFFECTS OF THE INVENTION According to the present invention, since the gap can be fixed on the air gap side of the first core, it is possible to provide an ignition coil for an internal combustion engine that is less affected by deterioration in performance and variations.

[Embodiment] Next, an ignition coil for an internal combustion engine of the present invention will be described based on an embodiment shown in the drawings. FIG. 1 is a cross-sectional view of an internal combustion engine ignition coil (hereinafter abbreviated as ignition coil) 1.

The ignition coil 1 of the present embodiment is excited by the energization of the primary coil 2 to accumulate magnetic energy, and the energization of the primary coil 2 is stopped to release the accumulated magnetic energy during energization. And a core 4 for generating an induced electromotive force in the secondary coil 3.

The core 4 includes a first T-shaped first core 5 and a second substantially U-shaped second core 5.
The first core 5 is arranged inside the second core 6 as shown in FIG.

The first core 5 is obtained by punching a grain-oriented thin plate-shaped magnetic plate (for example, soft iron) into a substantially T shape by pressing, and laminating a plurality of the molded products and press-crimping the one end surface 5a to the other end surface 5b. Is more widely formed. That is, the other end surface 5b of the first core 5 is provided so as to have a larger area than the one end surface 5a. The first core 5 is integrally formed with a resin-made primary spool 7 forming a winding frame portion of the primary coil 2.

One end (lower end in FIG. 1) of the primary spool 7 is the first core 5
A protruding portion 7a that is provided at the same height as one end surface 5a of the first core 5, that is, on the same surface, and that protrudes from the other end surface 5b of the first core 5 on the other end side.
(The gap forming member of the present invention) is integrally provided. The total length of the primary spool 7 including the protruding portion 7a (the length in the vertical direction in FIG. 1) is determined by the vertical width of the inner space of the second core 6 into which the first core 5 is inserted (the vertical length in FIG. 1). It is formed slightly larger than the length in the direction).

Therefore, the primary spool 7 is fixed in the inner peripheral portion of the second core 6 in the lengthwise direction in a press-fitted state. At this time, the first core 5 integrally formed with the primary spool 7 is in contact with one end surface 5a of the first core 5 being pressed against one side surface 6a of the second core 6, and the other end surface 5b of the first core 5 is in contact therewith. An air gap is formed between the second core 6 and the other side surface 6b of the second core 6.

In this air gap, a plate-shaped permanent magnet 8 is arranged over the entire other end surface 5b of the first core 5. The permanent magnet 8 is a rare-earth magnet that generates a large magnetic force even if it is thin, and the magnetic flux generated by exciting the first core 5 is repulsive, that is, the surfaces adjacent to each other have the same pole. It is arranged so that.

Similar to the first core 5, the second core 6 is obtained by punching a particle-oriented thin plate-shaped magnetic plate (for example, soft iron) into a substantially square shape by a press or the like, and laminating a plurality of the molded products and press-crimping the molded products. , Is integrally formed with the resin coil case 9.

In this ignition coil 1, the above-mentioned first core 5 is fitted on the primary spool 7 around which the primary coil 2 is wound, and around the primary spool 7 and around which the secondary coil 3 is wound.
It is configured as an assembly with the next spool 10, assembled with the permanent magnet 8 and press-fitted and fixed in the second core 6, and then integrally molded in the coil case 9 with a casting resin (not shown) such as epoxy resin. .

As shown in FIG. 1, due to variations in the dimensions of the core 4 (length of the first core 5: h1, inner peripheral width of the second core 6: h2) and thickness hm of the permanent magnet 8, the first Even when a gap S is formed in each joint surface of the core 5, the second core 6 and the permanent magnet 8, in this embodiment, the protruding portion 7a provided on the primary spool 7 is provided.
The one end surface 5a of the first core 5 to the one side surface 6a of the second core 6
In order to press-fit and fix the primary spool 7 integrally formed with the first core 5 into the second core 6 in a state of being brought into contact with the first core 5,
There is no gap S between the one end surface 5a of the core 5 and the one side surface 6a of the second core 6, and the air gap side of the first core 5 (that is, the other end surface 5b of the first core 5 and the permanent magnet 8). And the gap S is fixed between the permanent magnet 8 and the other side surface 6b of the second core 6).

There are three kinds of places where the gap S is generated, as shown in FIGS. 1 to 3. Here, the performance of the ignition coil 1 (variation of secondary arc energy) depending on the place where the gap S is generated is measured. did.

The core 4 shown in FIG. 1 ((A) in FIG. 4) is the case shown in this embodiment, and a gap S is formed between the permanent magnet 8 and the other side surface 6b of the second core 6. This is the case. In the core 4 shown in FIG. 2 ((a) in FIG. 4), the permanent magnet 8 is fixed to the other side surface 6b of the second core 6, and the permanent magnet 8 and the other end surface 5b of the first core 5 are connected. This is the case where a gap S is formed between them. Further, the core 4 shown in FIG. 3 ((c) in FIG. 4) has a gap S between the one end surface 5a of the first core 5 and the one side surface 6a of the second core 6.
Is the case that occurs.

As a result of the measurement, as shown in FIG. 4, there is a large variation in performance only when the gap S occurs between the one end surface 5a of the first core 5 and the one side surface 6a of the second core 6 (c). The performance degradation is also significant.

As can be seen from this measurement result, the gap S caused by variations in the dimensions of the core 4 (the first core 5 and the second core 6) and the thickness dimension of the permanent magnet 8 is set to the air gap side of the first core 5 (that is, the first core 5). Between the other end surface 5b of the one core 5 and the permanent magnet 8,
Alternatively, by fixing to the permanent magnet 8 and the other side surface 6b of the second core 6, one end surface 5a side of the first core 5 (one end surface 5a of the first core 5 and one side surface 6a of the second core 6). By configuring so that the gap S is not generated in (between), it is possible to suppress performance deterioration and performance variation of the ignition coil 1.

In this embodiment, a projecting portion 7a is provided on the other end side of the primary spool 7 and is press-fitted and fixed in the second core 6, so that the one end surface 5a of the first core 5 can be inserted into the second core 6. Although contacted with the side surface 6a, as shown in FIG. 9, a convex portion 9a (gap forming member of the present invention) is formed on the inner peripheral side of the coil case 9 integrally formed with the second core 6, You may make it press-fit.

Further, as shown in FIG. 1, the permanent magnet 8 is fixed to the other end surface 5b of the first core 5, but as shown in FIG.
The permanent magnet 8 may be fixed to the other side surface 6b of the second core 6 so that a gap S is formed between the permanent magnet 8 and the other end surface 5b of the first core 5.

The first core 5 has a substantially T shape and the second core 6 has a substantially square shape, but the first core 5 is not limited to such a shape, and the first core 5 is a substantially I shape and the second core 6 is a substantially U shape. Also good.

 A second embodiment of the present invention is shown in FIGS.

 FIG. 5 is an exploded perspective view of the ignition coil device 1.

 The same parts as those in the first embodiment are designated by the same reference numerals.

The ignition coil 1 of this embodiment includes a first core 5, a primary spool 7 around which a primary coil (not shown) is wound,
Secondary spool 1 around which a secondary coil (not shown) is wound
0 and a connector 11 for electrical connection with the outside are integrally assembled and housed in a coil case 9 in which the second core 6 is incorporated.

The permanent magnet (not shown) is arranged on the other end surface 5b side of the first core 5 having a large area, and is fixed to the inner peripheral portion of the second core 6 in advance.

The primary spool 7 in which the first core 5 is incorporated is provided with the other end side protruding from the other end surface 5b of the first core 5 by the thickness dimension of the permanent magnet, and one end is flush with the one end surface 5a of the first core 5. It is provided on the same surface. Further, at both ends on the other end side of the primary spool 7, a projecting portion having a slight height is formed.
7b (gap forming member of the present invention) is formed, and the total length from the protruding portion 7b to one end of the primary spool 7 is slightly larger than the length of the inner hollow portion of the second core 6 into which the first core 5 is inserted. Has been formed.

As a result, the first core 5 inserted into the inner space of the second core 6 is arranged so that its one end surface 5a is pressed against the one side surface 6a of the second core 6. Therefore, a gap generated between the first core 5 and the second core 6 due to variations in the core size and the thickness size of the permanent magnet is generated on the other end surface 5b side of the first core 5 having a large area.

The connector 11 has a structure that fits into both the coil case 9 and the primary spool 7, and is movable with respect to the primary spool 7 in the longitudinal direction of the first core 5 (shown by the arrow in FIG. 5). It is provided.

On the back side of the connector 11, a first fitting portion 12 for fitting with the coil case 9 and a second fitting portion 13 for fitting with the primary spool 7 are provided.

As shown in FIG. 6 (top view of the connector 11 ), the first fitting portion 12 is composed of a pair of fitting grooves 12a provided on both left and right sides of the connector 11, and the fitting groove 12a has a bottom portion at the bottom. , Mating groove 12
An engaging portion 12b having a convex cross section that extends along a is formed.

The second fitting portion 13 is a male fitting portion 13a having a rectangular parallelepiped shape.
And a convex portion 13b protruding from the male fitting portion 13a. The male fitting portion 13a and the convex portion 13b are provided on a flat plate 14 which stands upright on the rear surface of the connector 11 (sixth). See figure).

On the other hand, in the coil case 9, a concave portion 9b corresponding to the rear surface shape of the connector 11 is formed in a part of the side wall corresponding to the mounting position of the connector 11, and the inner peripheral edge of the concave portion 9b has a first concave portion A guide groove 9c that is fitted with the fitting portion 12 is formed.

A box-shaped fitting portion 15 into which the second fitting portion 13 of the connector 11 is fitted is provided on the other end side of the primary spool 7. As shown in FIG. 7 (top view of the primary spool 7), the fitting portion 15 corresponds to the female fitting portion 15a having a rectangular cross section corresponding to the male fitting portion 13a and the convex portion 13b. Recess
It consists of 15b and. Then, the female fitting portion 15a and the concave portion 15
Protrusions 15c and 15d that engage with the male fitting portion 13a and the convex portion 13b are formed on the two opposing surfaces of b.

Here, the female fitting portion 15a, as shown in FIG.
Vertical dimension L1 of the opening (longitudinal dimension of the first core 5)
Is set to be larger than the thickness dimension L2 of the male fitting portion 13a. For this reason, the male fitting portion 13a fitted to the female fitting portion 15a has a vertical direction (eighth direction) with respect to the female fitting portion 15a.
It can be moved in the direction of the arrow). That is, the primary spool 7 and the connector 11 are fitted to each other in a relatively movable state in the longitudinal direction of the first core 5.

 Next, the operation of the second embodiment will be described.

In this ignition coil 1, a connector 11 is attached to a primary spool 7, and the connector 11 is further attached to a coil case 9.
Form a structure that can be assembled into.

In this case, the connector 11 is fixed to the coil case 9, but is fitted to the primary spool 7 so as to be movable in the longitudinal direction of the first core 5.

However, in the conventional ignition coil in which the connector 11 is fixed to the primary spool 7, the one end surface 5a of the first core 5 is prevented from being pressed against the one side surface 6a of the second core 6 when assembled in the coil case 9. Then, there is a possibility that a force that pulls the primary spool 7 toward the other end side is generated. In this case, since a gap generated between the first core 5 and the second core 6 due to variations in the core size and the thickness size of the permanent magnet is formed on the one end face 5a side where the area of the first core 5 is small, This results in deterioration of the performance of the ignition coil.

On the other hand, in the present embodiment, the connector 11 fitted with the coil case 9 has the first core 5 with respect to the primary spool 7.
Since it can move in the longitudinal direction of the primary spool 7
Even with the structure in which the connector 11 and the connector 11 and the coil case 9 are fitted to each other, the primary spool 7 is not attracted to the other end side, and by the effect of the projection 7b provided on the primary spool 7, One end surface 5a having a small area of the one core 5 can be pressed against and brought into contact with one side surface 6a of the second core 6.

As a result, a gap generated between the first core 5 and the second core 6 is formed (fixed) on the side of the other end surface 5b having a large area of the first core 5, so that the performance of the ignition coil 1 is deteriorated. Can be suppressed.

In this embodiment, the primary spool 7 and the connector 11
Although the two are relatively movable by mating with each other, the connector 11 may be structured so as to be mated with the secondary spool 10, and the both may be relatively movable.

Further, the connector 11 may be provided between the connector 11 and the coil case 9 so as to be movably fitted to the coil case 9 in the longitudinal direction of the first core 5.

[Brief description of drawings]

1 to 4 show a first embodiment of the present invention, and FIGS. 1 to 3 show a cross section of an ignition coil for an internal combustion engine showing an arrangement of a first core, a second core and a permanent magnet. Figure,
FIG. 4 is a measurement result showing a comparison of coil performance depending on the location where the gap is generated. 5 to 8 show a second embodiment of the present invention, FIG. 5 is an exploded perspective view of an ignition coil, FIG. 6 is a top view of a connector, FIG. 7 is a top view of a primary spool, FIG. 8 is a state diagram showing a fitted state of the primary spool and the connector. FIG. 9 is an enlarged view of an essential part showing a modified example of the arrangement of the core and the permanent magnet. In the figure, 1 ... Ignition coil for internal combustion engine, 2 ... Primary coil, 3 ... Secondary coil, 5 ... First core 5a ... One end surface (one end) of the first core, 5b ... Of the first core The other end surface (the other end portion) 6 ... Second core, 6a ... One side surface (one end portion) of the second core 6b ... The other side surface (the other end portion) of the second core, 7 ... Primary spool (made of resin Member) 7a ... Projection (gap forming member of the present invention) 7b ... Projection (gap forming member of the present invention) 8 ... Permanent magnet, 9 ... Coil case (resin member) 9a. Convex portion of coil case (gap forming member of the present invention) "

Front Page Continuation (72) Inventor Shinji Oyabu 1-1, Showa-cho, Kariya, Aichi Prefecture, Nihon Denso Co., Ltd. (72) Inventor Toshiaki Yamaura 1-1, Showa-cho, Kariya, Aichi Nippondenso Co., Ltd. (56) Reference JP-A-1-257311 (JP, A)

Claims (4)

[Claims] 1. A primary coil and a secondary coil; a first core penetrating the primary coil and the secondary coil; one end contacting with one end of the first core and the other end through an air gap; And a second magnetic path that faces the other end of the first core and forms a closed magnetic path including the air gap.
A core, a plate-shaped permanent magnet arranged in the air gap so as to repel the magnetic flux generated by energizing the primary coil, and the first core and the second core in the air gap portion. Is interposed between the one end of the first core and the second core.
A gap forming member that forms the air gap between the other end of the first core and the other end of the second core in a state where one end of the core is pressed and brought into contact with the other end of the first core. A characteristic ignition coil for an internal combustion engine. 2. The ignition coil for an internal combustion engine according to claim 1, wherein the gap forming member is the first core or the second core.
It is composed of a resin member integrally molded with at least one of the cores, and between the first core and the second core on the side of the air gap, the other end of the first core and the second core.
An ignition coil for an internal combustion engine, which is interposed so as to be separated from the other end of the core. 3. The ignition coil for an internal combustion engine according to claim 1, wherein the first core has a larger area where the other end of the first core faces the second core than the one end of the first core. An ignition coil for an internal combustion engine, which is characterized in that 4. The ignition coil for an internal combustion engine according to claim 1, wherein the second core is provided with the one end portion and the other end portion in parallel with each other, The ignition coil for an internal combustion engine, wherein the ignition coil is arranged between the one end and the other end of the second core in a press-fitted state via the gap forming member.