JP2003086430A - Dc-dc converter transformer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thin DC-DC converter transformer which can easily perform accurate management of core processings. SOLUTION: This DC-DC converter transformer comprises a rivet-type core 8, consisting of a bottom surface 81 and a magnetic core 82 which is integrally projected upward at the center of the bottom surface 81, a pot-type core 9 consisting of a cylindrical part 91 and a top wall 92 to close the cylindrical part and a coil 86, consisting of a primary coil 84 and a secondary coil 85. The coil 86 is engaged with the magnetic core 82 of the rivet-type core 8 and the rivet-type core 8 engaged with the coil 86 is covered with the pot-type core 9 to mutually connect and fix the rivet-type core 8 and pot-type core 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a DC-DC converter transformer, and more particularly, to a thin DC-DC converter transformer in which core machining accuracy control is easy.

[0002]

2. Description of the Related Art In response to the demand for miniaturization of DC-DC converter modules as a whole, it has been demanded that the transformers used therein also be made thinner. Where DC-DC
In order to make the converter transformer thin, the following various methods are adopted. Referring to FIG. 4, the E-shaped cores may be laterally opposed to each other to reduce the height.
Reference numeral 2 is a left and right E-shaped core made of a magnetic material, and 3 is a bobbin made of a synthetic resin material. The left E-shaped core 2 extends from the left connecting rod 21, the left outer legs 22 that extend from both ends of the left connecting rod 21 at right angles to each other, and the middle portion of the left connecting rod 21 that extends parallel to the left outer leg 22. It consists of the left metatarsal 23. Right side E
The mold core 2 includes a right connecting rod 21, parallel right outer legs 22 extending at right angles from both ends of the right connecting rod 21, and a right connecting rod 2
The right middle foot 23 extending from the middle part of 1 parallel to the right outer foot 22
Consists of The thickness of the left middle foot 23 is slightly thinner than the thickness of the left connecting rod 21 and the left outer foot 22, and the level of the upper surface thereof is lower than the upper surface level of the left connecting rod 21 and the left outer foot 22. . Similarly, the thickness of the right middle foot 23 is also the right connecting rod 2
1 and the thickness of the right outer foot 22 are slightly thinner, and the level of the upper surface thereof is lower than the level of the upper surfaces of the right connecting rod 21 and the right outer foot 22. The bobbin 3 has a tubular portion 31.
A collar 32 protrudingly formed on the outside of the tubular portion 31, a through hole 33, and bobbin end portions 34 formed at both ends of the tubular portion 31.
And a lead terminal 35 protruding from the bobbin end 34.
Is formed by. A coil (not shown) is wound between the collars 32 on the outside of the tubular portion 31 of the bobbin 3. 2 in the tube 31
When the next coil is wound, the through hole 33 of the tubular portion 31 is formed.
The left middle foot 23 of the left E-shaped core 2 from the left side, and the right middle foot 23 of the right E-shaped core 2 from the right side into the through hole 33 of the tubular portion 31 to press the left E-shaped core 2 into the bobbin 3. And the right E-shaped core 2 is assembled and coupled. In this state, the left end E-shaped core 2 and the right side E-shaped core 2 are engaged with each other by the outer foot tips and the middle foot tips of each other to form a magnetic path.

By the way, the left E-shaped core 2 and the right E-shaped core 2 made of a magnetic material are generally manufactured by press-molding and sintering magnetic material powder in a mold, so that the product is always deformed. Therefore, it is difficult to obtain a product having a constant shape and size, and there is a limit to the accuracy control. That is, when the left and right E-shaped cores 2 are thinly configured including the outer foot and the middle foot, it becomes difficult to control the accuracy of the shape and dimension. Since it is necessary to form the middle feet 23, 23 particularly thinly, it is difficult to control the accuracy of the shape and dimension thereof. If the control of the accuracy of the shape and dimension is insufficient, the left E-shaped core 2 and the right E-shaped core 2 are assembled and coupled to the bobbin 3 and the outer foot tip comrades and the middle foot tip comrades are engaged with each other. In this case, the matching cannot be performed accurately and the magnetic resistance increases.

Referring to FIG. 5, the height can be reduced by combining a drum-shaped drum-shaped core and a cylindrical core for magnetically shielding the drum-shaped core. Reference numeral 4 denotes a drum-shaped drum core made of a magnetic material, 5 a cylindrical core made of a magnetic material, and 6 a base made of a synthetic resin material. The drum-shaped core 4 is composed of a magnetic core portion 41 and an annular flange portion 42 formed at the upper and lower ends thereof, and an annular flange portion 42 is provided outside the magnetic core portion 41.
A coil (not shown) is wound between them. The drum-shaped core 4 with the coil wound thereon is joined and fixed to the base 6,
The cylindrical core 5 is joined and fixed to the base 6 while being fitted to the drum core 4. The terminal of the coil is connected to the lead terminal 61 formed to project on the base 6.

The drum type core 4 and the cylindrical type core 5 of this conventional example are also manufactured by press-molding magnetic material powder in a mold and sintering, so that the product is always deformed, and its shape and dimension are inevitable. There is a limit to the control of accuracy. In particular, there is a control limit in the accuracy of the outer diameter and the thickness of the annular flange 42 of the manufactured drum type core 4. That is, the gap between the peripheral edge of the annular flange 42 of the drum core 4 and the inner peripheral surface of the cylindrical core 5 is not constant, which makes management difficult. Referring to FIG. 6, the E-shaped cores may be vertically opposed to each other to reduce the height. Reference numerals 7 are upper and lower E-shaped cores made of a magnetic material. The E-shaped core 7 includes a connecting rod 71 and a connecting rod 7
It is composed of mutually parallel outer legs 72 that extend at right angles from both ends of 1, and magnetic core portions 73 that extend from an intermediate portion of the connecting rod 71 in parallel with the outer legs 72. 74 is a terminal fixing member made of a synthetic resin material, and a lead terminal 75 is formed in a protruding manner. The terminal fixing member 74 is joined and fixed to the side of the connecting rod 71 of the lower E-shaped core 7. Here, the magnetic core portion 7 of the lower E-shaped core 7
3, the upper E-shaped core 7 is vertically opposed to the lower E-shaped core 7 and the coil in a state in which a coil (not shown) is fitted and assembled and coupled. The terminal of the coil is connected to the lead terminal 75 formed to project on the terminal fixing member 74.

Also in this conventional example, since the E-shaped core 7 is manufactured by press-molding magnetic material powder in a mold and sintering, the molding thickness of the E-shaped core 7, especially the magnetic core portion of the core. There is a control limit in the thickness accuracy of 73.

[0007]

SUMMARY OF THE INVENTION The present invention provides a DC-DC converter transformer that solves the above problems.

[0008]

According to a first aspect of the present invention, there is provided a rivet type core 8 including a bottom portion 81 and a magnetic core portion 82 which is integrally formed so as to project upward at a central portion of the bottom portion 81, and a tubular portion 91.
And a top wall 92 for closing the same and a pot type core 9 and a coil 86 including a primary coil 84 and a secondary coil 85. The coil 86 is fitted to the magnetic core portion 82 of the rivet type core 8. The rivet core 8 in which the coil 86 is fitted and combined is covered with the pot core 9 to form a DC-DC converter transformer in which the rivet core 8 and the pot core 9 are jointly fixed.

According to a second aspect of the present invention, in the DC-DC converter transformer according to the first aspect, the rivet type core 8 and the pot type core 9 are formed by press-molding magnetic material powder in a die and sintering it. The manufactured DC-DC converter transformer was constructed. A third aspect of the present invention is the DC-DC converter transformer according to any one of the first and second aspects, in which the lead terminal 80 is formed on the bottom surface portion 81 of the rivet core 8 and the primary of the coil 86. D in which the coil terminal lead-out portion 841 and the secondary coil terminal lead-out portion 851 are connected to the lead terminal 80
A C-DC converter transformer was constructed.

Further, claim 4: claim 1 to claim 3
In the DC-DC converter transformer described in any of the above, the magnetic core portion 82 of the rivet type core 8 is ground, or the magnetic core portion 82 and the pot type core 8 are formed by interposing a gap adjusting member made of a non-magnetic material. A magnetic path between the core 9 and the inner surface of the top wall 92 was adjusted to form a DC-DC converter transformer in which the rivet core 8 and the pot core 9 were jointly fixed.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described with reference to the examples of FIGS. Figure 1 is DC-DC
It is a figure which shows the outer surface of the Example of a converter transformer, FIG.1 (a) is the figure which looked at the Example from above, FIG.1 (b) is the figure which looked at the Example from the up-down direction, FIG.1 (c) is It is the figure which looked at the Example from the left-right direction. FIG. 2 is a view showing a lead terminal attached and fixed to a rivet-type core.
Is a view of the rivet core viewed from above, FIG. 2B is a view of the rivet core viewed from above and below, and FIG. 2C is a view of the rivet core viewed from below. 3A and 3B are views for explaining the lead terminal and the coil, FIG. 3A is a view of the lead terminal as viewed from above, and FIG. 3B is a view of the lead terminal as viewed from below in FIG. 3A. FIG.3 (c) is a figure which shows a coil.

In FIGS. 1 and 2, reference numeral 8 denotes a rivet type core, which has a quadrangular bottom portion 81. The bottom surface portion 81 has a quadrangular shape as a whole, but the four corner portions are small and are partially missing in the shape of an equilateral triangle to be a strict octagonal shape. A magnetic core portion 82 is integrally formed so as to project upward at the center of the bottom portion 81. Steps 83 corresponding to the outer dimensions of the U-shaped cross-section mounting portion 801 of the lead terminal 80 and the thickness of the sheet metal, which will be described later, are formed on the four corners of the bottom surface portion 81, which are the cutout portions. There is. The rivet core 8 described above is manufactured by press-molding magnetic material powder in a mold and sintering.

Reference numeral 9 denotes a quadrangular box-shaped pot type core, which comprises a tubular portion 91 and a top wall 92 for closing the tubular portion 91. The peripheral edge of the opening of the pot core 9 is formed so as to correspond to the shape and size of the upper surface of the rivet core 8. Pot core 9
Is also manufactured by press-molding magnetic material powder in a mold and sintering this. In particular, referring to FIG. 3A and FIG. 3B, the lead terminal 80 is made of a sheet metal as a raw material and is subjected to sheet metal processing to form a U-shaped cross-section mounting portion 801 and a U-shaped cross-section mounting portion 801 A connecting portion 802 is integrally formed and extended. In FIG. 3C, reference numeral 86 is a coil composed of the primary coil 84 and the secondary coil 85. The primary coil 84 has a primary coil terminal lead-out portion 841 and the secondary coil 85 has a secondary coil terminal lead-out portion 851.

Here, by combining the above components, DC-
To configure the DC converter transformer, first, the lead terminals 80 are attached to the bottom surface portion 81 by fitting the mounting portions 801 having a U-shaped cross section into the steps 83 formed on the upper and lower surfaces of the corner portion of the bottom surface portion 81. deep. Then, the magnetic core portion 8 formed to project at the central portion of the bottom surface portion 81 of the rivet core 8
2 is fitted with the primary coil 84 and the secondary coil 85, and
The secondary coil terminal lead-out portion 841 and the secondary coil terminal lead-out portion 851 are connected to the connecting portion 8 of the respective lead terminals 80.
Wrap around 02 and connect by soldering. Next, the pot type core 9 is covered, and the peripheral edge of the opening is joined and fixed to the upper surface of the rivet type core 8.

The above rivet type core 8 and pot type core 9
Prior to the mutual joining, the end surface of the magnetic core portion 82 of the rivet core 8 is ground, and the end surface of the magnetic core portion 82 faces the end surface of the magnetic core portion 82 in the spout where both are joined.
Of the top wall 92 of the pot core 9 to adjust the magnetic path, or between the end face of the magnetic core portion 82 and the inner face of the top wall 92 of the pot type core 9 facing the end face. The magnetic path is adjusted by interposing a gap adjusting member. After the magnetic path is adjusted, the rivet core 8 and the pot core 9 are bonded and fixed to each other.

[0016]

As described above, according to the present invention, since the core is designed in the simple shape structure of the rivet type core 8 and the pot type core 9, the finished dimensional accuracy is low, but Dimensional accuracy to be controlled for the core even when manufactured by pressure molding and sintering of magnetic material powder suitable for mass production processing, particularly, the end surface of the magnetic core portion 82 and the top wall 92 of the pot-shaped core 9 facing this. The dimension between the inner surface and the inner surface can be easily set to properly adjust the magnetic path.

By designing the diameter of the magnetic core portion 82 of the rivet type core 8 to be large so that the magnetic coupling area of its end face is wide, the magnetic path can be adjusted efficiently. Further, by designing the diameter of the magnetic core portion 82 to be large, it is possible to easily increase the degree of magnetic coupling structurally, reduce magnetic leakage, and increase efficiency on the circuit and reduce noise. Further, the gap between the end surface of the magnetic core portion 82 that adjusts the magnetic coupling of the core and the inner surface of the top wall 92 of the pot type core 9 that opposes the gap is the rivet type core 8
By adjusting the end face of the magnetic core portion 82 in advance by polishing or by interposing a gap adjusting member made of a non-magnetic material in this gap, the rivet type core 8 and the pot type core 9 are assembled in the final assembly step. The work efficiency is improved by only joining and fixing.

[Brief description of drawings]

FIG. 1 is a diagram showing an outer surface of an embodiment.

FIG. 2 is a diagram showing a lead terminal attached and fixed to a rivet core.

FIG. 3 is a diagram illustrating a lead terminal and a coil.

FIG. 4 is a diagram illustrating a conventional example.

FIG. 5 is a diagram illustrating another conventional example.

FIG. 6 is a diagram illustrating still another conventional example.

[Explanation of symbols]

8 Rivet type core 81 Bottom part 82 magnetic core 84 primary coil 85 Secondary coil 9 Pot type core 91 tubular part 92 top wall

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Claims (4)

[Claims] 1. A rivet core comprising a bottom portion and a magnetic core portion integrally projecting upward at a central portion of the bottom portion, and a pot core comprising a tubular portion and a top wall closing the core portion. A rivet-type core comprising a coil composed of a primary coil and a secondary coil, the coil being fitted and combined with the magnetic core of the rivet-type core, and the pot-type core being covered on the rivet-type core in which the coil is fitted and combined. A DC-DC converter transformer characterized in that a pot-type core and a pot-type core are jointly fixed. 2. The DC-DC converter transformer according to claim 1, wherein the rivet core and the pot core are manufactured by press-molding and sintering magnetic material powder in a mold. Characteristic DC-DC converter transformer. 3. The DC-DC converter transformer according to claim 1, wherein a lead terminal is formed on a bottom surface of the rivet core, and a primary coil terminal lead portion of the coil and DC-characterized by connecting the secondary coil terminal lead-out part to the lead terminal
DC converter transformer. 4. The DC-DC converter transformer according to any one of claims 1 to 3, wherein the magnetic core of the rivet-type core is ground or a gap adjusting member made of a non-magnetic material is used. A DC-DC converter transformer characterized in that a magnetic path between a magnetic core portion and an inner surface of a top wall of a pot core is adjusted by interposing it so that the rivet core and the pot core are joined and fixed to each other.