JPH0124892Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to an iron core, particularly to an isolation device between the ends of an iron core laminate for maintaining a gap between opposing ends of the laminates constituting a closed magnetic circuit type iron core. An example of a product using such a closed magnetic circuit iron core is a closed magnetic circuit ignition coil, which includes an iron core, a primary,
Although there are models in which both secondary coils are housed in a case and immersed in insulating oil, an exterior mold type model is shown in Fig. 1. This converts the primary coil 1 into the secondary coil 2.
The coil is passed through the bobbin of the primary coil and stored vertically on the bottom 3' of the case 3 made of metal or synthetic resin, and the thermosetting resin 4 is injected into the case to fix the coil. An iron core 5 is passed through the hole in the bottom, and then an outer layer 6 is molded using a synthetic resin mold. The iron core 5 is an L-shaped iron core laminate 5a,
5b, one of the laminates is passed through the bobbin of the primary coil before molding, and then one end of both laminates are opposed at right angles, and the thickness is
A gap is maintained by sandwiching a spacer 7 made of paper or synthetic resin pieces of 0.3 to 1.00 mm, and then U-shaped cover plates 8a and 8b are placed on both sides except for the part that penetrates into the primary coil (see Fig. 2). ), then do the molding.

In this case, if the outer shape of the spacer 7 is formed into a square or rectangle according to the cross-sectional shape of the laminate, the thickness of the laminate will be determined by the thickness of the laminate, since the thickness of the iron core usually varies by about 10%. It varies based on the variation, and when the backing plates 8a and 8b are applied to both sides of the core, if the stacking thickness is smaller than the width of the spacer 7, the spacer 7 protrudes from both sides of the core and is pushed in by the backing plates.
As shown in FIG. 3, the iron core bends between the opposing ends and widens the gap, reducing the primary inductance of the product and lowering the generated voltage.
On the other hand, if the stacking thickness is larger than the width of the spacer 7, the plates of both laminates will come into contact with each other at the part where the width of the spacer is insufficient, thereby reducing the change in magnetic flux and increasing the primary inductance of the product. As a result of increased hysteresis, the generated voltage similarly decreases.

For this reason, in the past, several types of spacers with different widths were prepared and the width was selected according to the thickness of the laminate. However, this was extremely time-consuming and reduced productivity. Significantly inhibits.

Therefore, this proposal focuses on the fact that even if there is variation in the thickness of the laminate, the value only changes between the minimum variation value and the maximum variation value. This was developed with the aim of solving the above-mentioned problem by allowing the spacer to follow this variation, and the dimension between the opposite sides of the width of the spacer facing the stacking thickness direction of the laminate is be equal to or shorter than the minimum variation value of the stacked thickness of the core, and have a protrusion that is crushed by the cover plate protrude from one or both of the opposite sides, and the dimension including the protrusion between both opposite sides is the maximum stacked thickness of the core. It is characterized by having a variable value or more. 5A, B, and C show an embodiment of the present invention, in which the dimension ₁ between opposite sides 7a and 7b in the width direction of the spacer 7 is slightly smaller than the minimum fluctuation value min of the iron core, and 9 is One opposite side 7
It is a projection that projects integrally from a, and the dimension ₂ including the projection between both opposite sides, that is, in this example, the opposite side 7a
The dimension between the tip of the protrusion 9 and the opposite side 7b at the other end is adjusted to the maximum fluctuation value max of the iron core.

Therefore, when the stacked thickness of the iron core is the minimum, most of the protrusion 9 is crushed by the cover plate 8a as shown in FIG. 5B,
When the thickness of the iron core is maximum, the protrusion is not crushed (Fig. 5 C), and when the lamination thickness is normal, a part of the tip of the protrusion is crushed (Fig. 5 D). The spacer 7 can accommodate variations in the stacking thickness of the iron core.

Note that dimension ₂ does not necessarily need to be equal to the maximum variation value max of the iron core, and may be slightly larger than that, and dimension ₁ between opposite sides may be adjusted to the minimum variation value, and the number of protrusions may be The number is not limited to one, and there may be more than one as shown by the chain line.

But for example dimension ₁ is equal to the minimum variation value,
If dimension ₂ is larger than the maximum variation value, the amount of crushing of protrusion 9 will increase when the core stacking thickness is minimum, and this will cause an adverse effect if the gap widens. Therefore, it is preferable to It is preferable to make dimension ₁ shorter than the minimum variation value, and match dimension ₂ to the maximum variation value, so that when the stacked thickness of the iron core is the minimum, the amount of the protrusion crushed is minimized.

In order to reduce the amount by which the protrusion is crushed as much as possible, the protrusion 9 should be made to protrude from both the opposite sides 7a and 7b. Figure 6 shows an example of this case.
The dimension ₁ between opposite sides is smaller than the minimum variation value,
The dimension ₂ including the protrusions between both opposite sides, that is, in this embodiment, the dimension between the tips of the protrusions 9 protruding from both opposite sides is adjusted to the maximum variation value. Therefore, when used in a core with the smallest stack thickness, both protrusions 9 are partially crushed as shown in Figure 6B, and when used in a core with the largest stack thickness, as shown in Figure 6C. Both protrusions are not crushed.

If the thickness of the core is normal and its cross-sectional shape is square, then the dimension ₁ of each side of the spacer 7 should be shorter than the minimum variation value of the thickness of the core, as shown in Figure 7. The directionality of the spacer can be eliminated by making the length square, having projections 9 protruding from its four sides, and making the dimension ₂ between the projections on two sets of opposing sides equal to or slightly longer than the maximum variation value of stacking thickness. This improves work efficiency.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of an assembled state of the ignition coil in which the present invention can be implemented, FIG. 2 is a perspective view of a part of the above in an exploded state, and FIGS. 3 and 4 are explanatory diagrams showing the problems of the conventional method. FIG. 5A is a plan view of the first embodiment of the spacer according to the present invention, FIGS. 5B, C, and D are explanatory diagrams of its use, and FIG. 6A is a plan view of the second embodiment of the spacer according to the present invention. A plan view, FIGS. 6B and 6C are explanatory diagrams of their usage, and FIG. 7 is a plan view of still another embodiment of the spacer according to the present invention. In the figure, 5 is an iron core, and 5a and 5b are iron cores. 7 is a spacer, 7a and 7b are opposite sides in the width direction of the spacer,
8a and 8b are the backing plates, 9 is the protrusion, ₁ is the dimension between opposite sides of the spacer, and ₂ is the dimension including the protrusion between the opposite sides of the spacer.

Claims (1)

[Claims for Utility Model Registration] An iron core laminate in which the ends of two laminates constituting the core are opposed to each other with a spacer interposed therebetween, and backing plates are placed on both sides of both laminates across the opposing ends. In isolation devices between the ends of the body, in order to cope with variations in the thickness of the core laminate, the width of the spacer facing the stack thickness direction is set to the minimum variation value of the core laminate thickness. be equal to or shorter than that, have a protrusion that is crushed by the cover plate protrude from one or both of the opposite sides, and make the dimension between both opposite sides, including the protrusion, equal to or greater than the maximum variation value of the stacked thickness of the core. An isolation device between ends of an iron core laminate, characterized in that: