JPS5922306A - Magnetic core for discharge lamp stabilizer - Google Patents

Abstract

PURPOSE:To facilitate removal from the mold and to permit reuse of the same mold at the time of sizing (re-compressing) by a construction wherein, in the process of compacting powder in the powder metallurgy technique, the mold is provided at the side part thereof relative to the pressing direction with a taper at an angle of 1-20 degrees relative to the vetical line. CONSTITUTION:A mold is provided at the side part thereof relative to the pressing (drawing) direction with a taper at an angle of 1-20 degrees relative to the vertical line, because an angle not larger than 1 degree has no effect in facilitating removal from the mold and an angle not less than 20 degrees weakens the strength when assembled into a stabilizer. This facilitates removal from the mold at the time of the first pressing and pevents a magnetic core from adhering to and not separating from the mold. Even if the magnetic core is slightly expanded when removed after the first pressing, it is made possible to make sizing using the same mold as that which has been used for the first pressing.

Description

[Detailed Description of the Invention] Conventional magnetic cores for discharge lamp ballasts are formed by punching silicon steel plates with a press and then laminating them to form the magnetic core. Therefore, there are restrictions on the shape, such as rectangular or rectangular shapes. There was a drawback that it was impossible to escape from the restrictions of the bobbin, etc. The present invention has been made to solve the above-mentioned drawbacks.

Hereinafter, an explanation will be given based on the drawings. As illustrated in Fig. 1, when the side surface is parallel to the pressing direction (extraction direction), the magnetic core is in close contact with the mold and it is difficult to extract it. It is very difficult to press, and since the magnetic core expands from the mold after the first pressing, the same mold as the first time cannot be used for sizing (recompression), so a separate sizing mold is used. The mold was safe. In the present invention, for example, when the shape is as shown in FIG.
If it is less than °, it will not be effective in making it easier to remove, and
If the angle is more than 0°, the strength will be weakened when assembled into the ballast, so insert a chi-toe at an angle of 1° to 2000 on the side part in the vertical line with respect to the direction of removal (extraction direction). This makes it easier to remove the magnetic core during the first freeing process, and prevents the magnetic core from coming into close contact with the mold and becoming unable to separate from it. In addition, even if the magnetic core expands slightly after the first pressing, it can be sized (recompressed) using the same mold used for the first pressing. be. Here, one of the factors that influences the performance of the magnetic core is magnetic permeability, and as the magnetic permeability increases, the performance of the magnetic core improves. When the density of the magnetic core increases to 10, the permeability also increases, so sizing (recompression) improves the performance of the magnetic core.

Next, as illustrated in Figure I, a magnetic core without a depression at the center of the inner surface of the base is made of the same material and by the same powder metallurgy method.
A rectangular parallelepiped-shaped core L was manufactured under the same conditions, and when compared with a magnetic core of the same type made by cutting it, the performance of the magnetic core made using a mold as shown in FIG. 1 was lower.

This is because the density between the central leg portion 1 and both end leg portions 2 is non-uniform, and as a result, the magnetic permeability differs depending on the portion. This non-uniform density also causes cracks in the legs. However, as illustrated in FIG. 2, when a depression 4 is provided at the center of the inner surface of the base of the core, the density of the center leg 1 increases, the density of both end legs 2 and the center leg 1 becomes uniform, and the density of the magnetic core increases. The overall density has increased, and therefore the magnetic permeability has increased, and the performance as a magnetic core has been significantly improved. Also, by making the density uniform, cracks in the legs that occur immediately after being removed from the mold are eliminated. Also, as shown by the dotted line inside the magnetic core in FIG. 5, the magnetic flux does not flow in an angular manner6, but flows in an arc at each corner of the core7, as illustrated in FIG. Even if the recess 4 is provided at the center of the inner surface of the base, the performance as a magnetic core hardly changes, and the amount of material is reduced by the amount of the recess, leading to weight reduction and cost reduction. Furthermore, when assembled as a stabilizer,
It can also be used to determine the center position when covering with a base or cover.

Next, as described above, since the magnetic flux flows in an arc at each corner of the core 7, even if each corner and each ridgeline are removed, there will be no magnetic effect. Therefore, all or part of each corner part and all or part of each ridgeline part are rounded.
By attaching the ballast, the amount of material can be reduced, and the ballast will not be damaged by shocks that occur when assembling the ballast or when assembling the lighting equipment.

As described above, the present invention not only brings about good magnetic results in a magnetic core for a discharge lamp ballast using a powder metallurgy method, but also reduces the amount of material used, and therefore helps to reduce the weight of the ballast, which has become popular in recent years. In addition to increasing the size of lighting equipment, it has many features such as being able to reduce the size and weight of the equipment even a little, and providing lighting equipment at low cost.

[Brief explanation of drawings]

The drawings show an embodiment of the magnetic core of the ballast for a discharge lamp according to the present invention, and FIGS. 1 and 2 are cross-sectional views of the magnetic core, and FIG. 3 is a cross-sectional view of the magnetic core.
, FIG. 4 is a perspective view of the same, and FIG. 5 is a schematic diagram of the same. 1...Central leg 2...Both end legs 3...
・Basal central part 4 ・・Concavity 5 in the center of the basal inner surface
...Ridge patent applicant Kuroi Kosan Co., Ltd.

Claims (3)

[Claims] (1) In a magnetic core for a discharge lamp ballast made by powder metallurgy, in the process of compression molding powder by powder metallurgy, the side part with respect to the pressing direction (pull direction) is 1° to 20° with respect to the vertical line. A magnetic core for a ballast for a discharge lamp, characterized in that it is provided with a tip at an angle of . (2) A magnetic core for a ballast for a discharge lamp according to claim 1, wherein the magnetic core for a ballast for a discharge lamp is made by a powder metallurgy method, and a stub is provided at the center of the inner surface of the base of the magnetic core. (3) In a magnetic core for a discharge lamp ballast made by powder metallurgy, all or part of each corner of the magnetic core is rounded, and all or part of each ridgeline of the magnetic core is curved. A magnetic core of a ballast for a discharge lamp according to claim 1.