JPH01196106A - Split type ferrite core - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a split ferrite core used for countermeasures against electromagnetic noise in various electronic devices.

BACKGROUND OF THE INVENTION Split ferrite cores are commonly used to provide electromagnetic noise (EMI) attenuation for non-removable cables and the like. .

By the way, such a conventional split type ferrite core is
For example, as shown in FIG. 6, a pair of semi-annular ferrite cores 11.1 are divided into two in the radial direction into an annular ferrite core.
2, each of which had a flat cross-section, so it took time and effort to accurately align the cross-sections when combining the two after winding cables and the like.

Furthermore, even if the semi-annular ferrite cores 11 and 12 are combined and fixed with tape, etc., the divided cross-sections tend to shift due to the restoring force against twisting of the wrapped cables, etc., which causes variations in the amount of electromagnetic noise attenuation. There is a high possibility that the damping effect will be reduced.

In other words, there is a problem in that a normal damping effect cannot be obtained because the damping characteristics of the core change.

■-Pod This invention was made in view of the above points, and aims to prevent variations in the electromagnetic noise attenuation effect by preventing misalignment of the split cross section after combining the split ferrite cores. .

Structure □Friend In order to achieve the above-mentioned object, the present invention has a split type ferrite core formed by dividing an annular ferrite core into two in the radial direction, in which each divided cross section of a pair of divided semi-annular ferrite cores is fitted into each other. The concave and convex shapes are designed to fit together.

Furthermore, it is desirable that the direction in which the concavities and convexities are formed on one and the other of the two divided cross sections of each semi-annular ferrite core are made to be different.

EMBODIMENT OF THE INVENTION Hereinafter, this invention will be specifically explained based on embodiments.

FIG. 1 is an external perspective view of a split ferrite core showing an embodiment of the present invention.

This split type ferrite core 1 consists of a pair of semi-annular ferrite cores 2 and 3 formed by dividing an annular ferrite core into two in the radial direction, and the divided cross sections 2a and 3a and 2b and 3b are as shown in the figure. 2a and 38 have an uneven shape that fits into each other, and furthermore, the unevenness formation direction (A
-A' force direction and unevenness forming direction of divided cross sections 2b and 3b (B
-T3' direction) is even 90 degrees.

When using this split type ferrite I/core 1, as shown in FIG. After winding, the semi-circular ferrite 1 to core 2. The divided cross-sections having concave and convex shapes opposite to each other are fitted and assembled, and the tape 5 is wrapped around the fitted portion to fix it.

Therefore, semi-annular ferrite 1-core 2. The assembling work of B becomes easier, and even if the restoring force against the twisting of the wrapped cable 5 or external force is applied, one split cross section 2a
Since the direction in which the fitting portion of 2b and 3a and the fitting portion of the other divided cross section 2b and 3b can be separated is 90 degrees apart, each acts to prevent the other fitting portion from shifting, and the divided cross sections Compared to conventional split-type ferrite cores, which were flat, misalignment is much less likely to occur.

Next, other embodiments of the split type ferrite core according to the present invention are shown in FIGS. 3 and 4.

Fig. 3 shows an example of a small split-type ferrite core with a relatively small inner diameter d. It is surrounded by a heat-shrinkable tube 6, and hot air is applied from the outside to shrink and fix the heat-shrinkable tube 6.

Figure 4 shows an example of a split type ferrite core with a long length L in the axial direction. , and fix it by wrapping tape 5 in the circumferential direction.

In addition, in this example, two semi-annular ferrite cores 2' and 3'
Although the directions in which the unevenness is formed on the divided cross sections are in the same direction, sliding in the radial direction is prevented by the uneven fitting and tape fixing, and since the area of the uneven divided cross section is large, the friction effect causes it to move in the axial direction (Fig. (in the vertical direction) is also prevented, so there is no problem.

Next, a specific usage example of the split type ferrite core according to the present invention will be explained with reference to FIG.

This is a split type for electromagnetic noise countermeasures for the interface cable 9 used to connect between the controller board 7 inside the laser printer and the external interface board 8 for connecting the host 1 to external devices such as computers. This is an example using ferrite core 1.

That is, since the harmonics of the microcomputer active clock signal (for example, 16MH2) output from the oscillator mounted on the controller board 7 leak to the outside through the interface cable 9, this interface cable 9 is connected to a split-type ferrite in the middle. It is wound around the core 1 to attenuate harmonics and prevent the emission of electromagnetic noise.

In this case, a connector (socket 1-) 71 for connecting the controller board 7 and the interface cable 9 is attached to the controller board 7 side, and a connector 72 is attached to one end of the interface cable 9. A connector (socket) 81 is placed on the external interface board 8 side for connection with
A connector 82 is attached to the other end of interface cable 9.

Each of these connectors is relatively large according to standards such as the R8-232C interface or Senronics interface, and cannot be wrapped around a general link-shaped fiber core through the interface cable 9, but the present invention The use of a split type ferrite core according to the invention is extremely effective because it is easy to install, and there is no fear that the split cross section will be misaligned after installation and the electromagnetic noise reduction effect will be reduced.

The split type ferrite core according to the present invention can be widely used for countermeasures against electromagnetic noise in various other electronic devices.

As explained above, according to the present invention, the split ferrite core can be easily installed, and the variation in the amount of electromagnetic noise attenuation after installation is reduced, thereby reducing electromagnetic noise in various electronic devices. Countermeasures can be taken effectively.

Furthermore, by making the direction in which the unevenness is formed on one and the other of the two divided sections of each semi-annular ferrite core different, it is possible to more reliably prevent displacement after fixing, so that the specified electromagnetic noise attenuation effect can be maintained for a long period of time. can be maintained reliably.

[Brief explanation of the drawing]

FIG. 1 is an external perspective view of a split type ferrite core showing an embodiment of the present invention; FIGS. 2 to 4 are external perspective views showing how various split type ferrite cores according to the invention are attached to a cable; FIG. 5 is a perspective view showing a specific usage example of the split-type ferrite core according to the present invention, and FIG. 6 is an external perspective view showing an example of a conventional split-type ferrite core. 1. Split type ferrite core 2.2', 3. "l' ・Semi-annular ferrite core 4
・Cable 5 Tape 6... Heat shrink tube 7 Controller board = 7
- 8... External interface board 9... Interface cable Figure 1 Figure 6

Claims (1)

[Scope of Claims] 1. In a split type ferrite core formed by dividing an annular ferrite core into two in the radial direction, each split cross section of a pair of split semi-annular ferrite cores forms an uneven shape that fits into each other. A split type ferrite core that is characterized by: 2. The split type ferrite core according to claim 1, wherein the direction in which the unevenness is formed on one and the other of the two divided cross sections of each semi-annular ferrite core is different.