JPH037932Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an isolation type switching power transformer used, for example, in a switching regulator.

Conventionally, in an insulation type switching power transformer, such as a transformer for a switching regulator, a primary coil is wound around a simple cylindrical coil bobbin, and an interlayer insulating paper or insulation tape is wound on the primary coil. After winding the secondary coil, if it is necessary to further wind the tertiary coil or other coils, wrap the interlayer insulating paper or insulating tape over the secondary coil again, and then wrap these coils on top of it. It has a structure in which it is wrapped. Further, in the lead-out portion from each coil, an insulating interval is maintained by a spacer or the like. For this reason, there is a drawback that winding the coil requires a great deal of time and effort, and there is also a drawback that reliability is lacking.

The present invention was developed in order to eliminate the above-mentioned drawbacks.In addition to winding each coil around concentric cylindrical bobbins with different diameters to create a multilayer structure, the lower ends of the other bobbins except for the innermost layer bobbin are wound in the axial direction. The present invention provides a switching power transformer in which a pair of opposing arc-shaped protrusions are formed, a coil lead is pulled out through the protrusions, and the bobbin is prevented from rotating by the protrusions.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIGS. 1 and 2 show an example of a first bobbin 1 in the innermost layer and a second bobbin 2 disposed outside the first bobbin 1 when the present invention is applied to a switching regulator. are shown respectively. As shown in FIG. 1, a base 3 is integrally formed at the lower end of the first bobbin 1, and this base 3 is connected to a pair of substantially parallel opposing hanging side walls 4.
A and 4B are provided on both sides, and terminal pin attachment portions 5A and 5B are formed integrally with these side walls 4A and 4B, respectively. A primary coil (not shown) is wound around the first bobbin 1 using, for example, section winding, and the lead of the primary coil is passed through one side wall of the base 3, for example, through the approximate center of 4A, and is attached to a terminal pin. It is connected to a corresponding terminal pin (not shown) of section 5A. The second bobbin 2 shown in FIG. 2 is fitted onto the outside of the first bobbin 1 to form a concentric cylindrical multilayer structure, and the central leg portion of the E-shaped core 6 shown in FIG. A switching regulator transformer is constructed by inserting the bobbin 1 into the center hole of the bobbin 1 from the base 3 side and forming a closed magnetic path with the corresponding I-shaped core 7. The core may be of type E or E instead of type E or I. Furthermore, although the cross sections of both outer legs of the E-shaped core may be of any shape such as rectangular, square, or circular, it is preferable that the central leg has a circular cross section as shown.

As shown in FIG. 2, the second bobbin 2 is integrally formed with a pair of arc-shaped protrusions 8A and 8B which protrude in the axial direction and are opposed to each other at the lower end, that is, the end surface on the base side. In this embodiment, these protrusions 8A and 8B have the same wall thickness as the bobbin 2 (of course, the wall thicknesses may be different), so that opposing portions of the lower end of the bobbin 2 protrude in the axial direction. It is in the form. These protrusions 8A, 8B are formed such that the distance d between the corresponding ends is equal to or only slightly larger than the distance between the parallel side walls 4A, 4B of the base 3. Of course, it is preferable that the ends of the protrusions 8A and 8B are formed to form parallel planes. In the illustrated embodiment, a secondary coil is section-wound on this second bobbin 2.
A slit 10 is formed in the axial direction in the collar portion 9 of the bobbin 2, which corresponds to one of the protrusions 8A and 8B, for example, 8A in the axial direction. Although two slits 10 are formed in this example, the number of slits 10 can be increased or decreased depending on the number of coil leads drawn out.

Since the second bobbin 2 is configured as described above, the secondary coil is wound around this bobbin 2, and the
When fitted to the outside of the first bobbin 1 shown in the figure, the ends of the pair of protrusions 8A, 8B of the second bobbin 2 are in sliding contact with the side surfaces of both side walls 4A, 4B of the base 3. fitted, so the second bobbin 2 does not rotate,
Its position is precisely regulated. Further, the lead of the secondary coil wound around the second bobbin 2 passes through the slit 10 of the flange 9 mentioned above, and further passes through one of the protrusions 8A to attach the terminal pin integrally formed on the base 3. Connected to the terminal pin of the Therefore, the protrusion 8A also functions as an insulating spacer, which is very useful. At this time,
The coil lead of the second bobbin 2 is connected to the opposite side wall of the base 3 from the lead of the first bobbin 1, that is, to the terminal pin on the 4B side, and the lead of the primary coil and the secondary coil are connected to the terminal pin on the side wall 4B. It is preferable to increase the dielectric strength by increasing the distance between them. That is, the second bobbin 2 is fitted onto the first bobbin 1 such that one protrusion 8A is in contact with the other side wall 4B of the base 3. If it is necessary to fit a third bobbin with a tertiary coil and other coils wound around the outside of the second bobbin 2, the second bobbin 2 shown in FIG. Exactly the same configuration
However, after forming a third cylindrical bobbin with a larger diameter and winding the required coil, it is fitted onto the outside of the second bobbin 2. At this time, it is preferable that the slit formed in the flange of the third bobbin be fitted on the opposite side of the slit in the flange of the second bobbin to increase the dielectric strength voltage between the drawer leads. . 3 and 4 are a bottom view and a vertical sectional view of a multilayer bobbin in which three bobbins are fitted, and in the figures, 11 is the third bobbin, and 12A and 12B are a pair of the third bobbin 11. Opposing arcuate protrusions; 13, the flange of the third bobbin 11; 14, an axial slit formed in the flange 13; 15, a lead extraction position from the coil wound on the first bobbin 1; , 16 indicates the lead extraction position from the coil wound on the second bobbin 2, and 17 indicates the lead extraction position from the coil wound on the third bobbin 11. As is clear from FIGS. 3 and 4, the lead leads are arranged on opposite sides of each layer, increasing the dielectric strength.

As described above, according to the present invention, each coil is wound around a concentric cylindrical bobbin, so the position can be reliably regulated, and there is no need to wind insulating interlayer paper or insulating tape. Also, since it is a cylindrical bobbin,
Winding work is easier and more efficient than square bobbins. Furthermore, since automatic winding is also possible, the winding time can be greatly reduced. Furthermore, since the pair of protrusions of the bobbin have both the function of stopping rotation and insulating the lead-out lead, the structure is simple, and there are many excellent advantages such as easy manufacture and low cost.

It should be noted that the above embodiments are merely illustrative of the present invention, and therefore, it goes without saying that various modifications and changes can be made as necessary. For example, each bobbin is not limited to a bobbin for section winding, and the number of cylindrical bobbins fitted therein is arbitrary. Furthermore, although the present invention has been applied to a switching regulator, it is not limited thereto.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an example of the first bobbin of the innermost layer of the switching power transformer according to the present invention, together with the associated base, terminal pin mounting portion, and core, and FIG. 2 is a perspective view showing an example of the second bobbin. Figures 3 and 4 are a bottom view and a vertical cross-sectional view of a multilayered bobbin in which three concentric cylindrical bobbins are fitted. 1: First bobbin, 2: Second bobbin, 3: Base, 4A, 4B: Pair of side walls of base 3, 5A, 5
B: Terminal pin attachment portion, 8A, 8B: Pair of protruding portions of second bobbin 2, 9: Flange portion of second bobbin 2, 10: Slit, 11: Third bobbin, 12
A, 12B: a pair of protrusions of the third bobbin 11;
13: Flange of third bobbin 11, 14: Slit.

Claims (1)

[Scope of utility model registration request] a base having a circular center hole and a pair of substantially parallel opposing side walls; and a first coil formed integrally with the base so as to be substantially concentric with the center hole of the base, and around which a primary coil is wound. a second cylindrical bobbin fitted on the outside of the cylindrical bobbin and around which a secondary coil is wound; forming an arc-shaped protrusion, the spacing between the corresponding ends of the protrusion being such that the opposing side walls of the base fit between the corresponding ends of the protrusion; A switching power supply characterized in that the second bobbin has a slit formed in a flange portion of the second bobbin corresponding to one of the pair of protruding portions in an axial direction for drawing out the coil lead. Trance.