JP3407766B2 - Transformer with intermediate yoke - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rectifier transformer for rectifying a secondary output to obtain a DC output.

[0002]

2. Description of the Related Art A transformer for a rectifier is provided with a triangular connection winding and a star connection winding as secondary windings in one transformer, and these are connected in a double three-phase bridge to obtain a rectified output. So-called 1
Two-phase rectification is used to obtain an output closer to DC. In the double three-phase bridge connection, it is necessary to match the output voltage of the triangular connection winding and the output voltage of the star connection winding as much as possible, but the number of turns is large because the secondary winding is a large current winding. Usually around 3 to 20 turns, which is small.
Therefore, if the primary winding is shared, a difference occurs in the output voltage between the triangular connection winding and the star connection winding. For example, in a combination in which the triangle connection secondary winding has 12 turns and the star connection secondary winding has 7 turns, a voltage difference of 7 × 3 ^0.5 -12 = 0.12 turns occurs. In order to eliminate this drawback, an iron core is made from three yokes: an upper yoke, an intermediate yoke and a lower yoke that magnetically connect the upper, middle and lower ends of the main leg of the three-phase core. Constitute. A triangular winding secondary winding and the corresponding primary winding are wound around the main leg above the intermediate yoke, and a star-shaped secondary winding and the corresponding primary winding are wound around the lower main leg of the intermediate yoke. Wind the wire. This allows the intermediate yokes to function in common, but as separate transformers. Japanese Patent Publication No. 1-29046 discloses that the secondary output voltages of the triangular connection winding and the star connection winding can be matched by adjusting the turns ratio of each winding by the primary winding. There is.

FIG. 5 is a sectional view showing the structure of a transformer having a conventional intermediate yoke. The iron core 1 includes three main legs 2 formed by stacking silicon steel plates, an upper end yoke 3 connecting both ends of the main leg 2, and a lower end yoke 4.
It is composed of an intermediate yoke 5 that connects the intermediate portion of the main landing gear 2. Although the joint between the main leg 2 and each of the yokes 3, 4, and 5 is not shown, the end portions of the silicon steel plate are cut obliquely and joined so as to partially overlap each other in each stack.

Further, in FIG. 5, a winding 6 composed of a primary winding 6A and a secondary winding 6B around which the main leg 2 is wound is arranged above the intermediate yoke 5, and below the intermediate yoke 5. Another winding 7 including a primary winding 7A and a secondary winding 7B around which the main leg 2 is wound is arranged. Insulating intermediate rings 8 and 9 are interposed between the windings 6 and 7. Primary winding 6A
A press ring 10 for pressing the winding 6 downward is arranged on the upper end surface of each of the secondary winding 6B and the secondary winding 6B, and a winding receiver 11 for receiving a pressing force from above is arranged on the lower end portion of the winding 7. Has been done.

FIG. 6 is a sectional view taken along line CC of FIG. In this section, the intermediate rings 8, 9 of FIG. 5 are not visible, but their outline is shown by the dotted lines. The intermediate rings 8 and 9 are rectangular insulating plates with a hole 12 formed in the center, and are provided for each main leg 2. The main leg 2 is passed through the hole 12, and an insulating spacer 13 is interposed between the intermediate rings 8 and 9.

FIG. 7 is a sectional view taken along line DD of FIG. The upper and lower iron frames 14 and 15 respectively press the upper end yoke 3 and the lower end yoke 4 from both sides to support the iron core. The frame 14 also serves as a base when the windings 6 and 7 are pressed by the press ring 10.
FIG. 8 is a sectional view taken along line EE of FIG. The intermediate yoke 5 passes through a gap 16 between the intermediate rings 8 and 9 secured by the spacer 13. The winding 6 is pressed downward by the press ring 10, and the intermediate ring 9 moves the intermediate yoke 5
It is configured so that the winding 7 is pressed without pushing down. By pressing the windings 6 and 7 with a predetermined force, the windings 6 and 7 withstand the electromagnetic force applied to themselves.

[0007]

However, the conventional device as described above has a problem that the axial thickness of the intermediate ring must be increased. Since the intermediate ring 9 is made of an insulating material such as laminated wood or a press board, its elastic coefficient is orders of magnitude smaller than that of a metal material such as iron. In FIG. 8, since the spacer 13 cannot be interposed at a portion through which the intermediate yoke 5 passes, the intermediate ring 9 is very easily bent between the spacers 13. When the intermediate ring 9 is partially deflected, the pressing force of the windings 6 and 7 is reduced. In order to avoid it, conventionally, the axial thickness d of the intermediate ring 9 is increased. As a result, the transformer as a whole becomes expensive, which is a factor of increasing the manufacturing cost.

An object of the present invention is to reduce the axial thickness of the intermediate ring.

[0009]

In order to achieve the above object, according to the present invention, three main legs and an end for magnetically connecting between the main legs at both axial end portions of the main legs. It has an iron core composed of a partial yoke and an intermediate yoke that magnetically connects between the main legs in the middle of the main leg in the axial direction, and windings for winding the main leg are provided on both sides of the intermediate yoke. Insulating intermediate rings are arranged along the end face of each winding on the intermediate yoke side, and an insulating spacer is interposed between the intermediate rings, and the intermediate ring formed by the spacers. It is preferable that the intermediate yoke is arranged in the gap of (1) and a spacer penetrating the intermediate yoke is added.

Further, in such a structure, the intermediate yoke may be divided into two in a direction perpendicular to the axis to form a gap, and the spacer may be penetrated in the gap. Alternatively, a hole may be formed in the intermediate yoke and a spacer may be passed through the hole.

[0011]

According to the structure of the present invention, since the spacer penetrating the gap or hole of the intermediate yoke is added, a new fulcrum can be formed at the place where the intermediate yoke passes. Since this fulcrum suppresses the bending of the intermediate ring, the axial thickness of the intermediate ring can be made smaller than the conventional one.

[0012]

EXAMPLES The present invention will be described below based on examples. FIG. 1 is a cross-sectional view of essential parts showing the configuration of a transformer provided with an intermediate yoke according to an embodiment of the present invention. Intermediate yoke 50
Is divided into two, and the gap 50A is secured by the gap material 18. A spacer 17 is newly added directly below the winding (not shown) in the gap 50A.

FIG. 2 is a sectional view taken along line AA of FIG. The spacer 17 is interposed between the intermediate rings 8 and 9 and serves as a fulcrum for preventing the intermediate ring 9 from being bent. Other configurations of FIGS. 1 and 2 are the same as the conventional configurations described in FIGS. 5 to 8. That is, FIG. 1 corresponds to the right part of FIG. 6, and FIG. 2 corresponds to FIG. In these figures, the same parts are designated by the same reference numerals, and detailed description thereof will be omitted. Spacer 17
Since the thickness d of the intermediate ring 9 can be made smaller than that of the conventional one, the height of the entire transformer is also reduced.

FIG. 3 is a cross-sectional view of essential parts showing the structure of a transformer provided with an intermediate yoke according to another embodiment of the present invention. A rectangular hole 51 </ b> A is formed immediately below a winding (not shown) of the intermediate yoke 51. A prismatic spacer 19 is newly added to the hole 51A. FIG. 4 shows FIG.
FIG. The spacer 19 is the intermediate ring 8,
It is interposed between the shafts 9 and serves as a fulcrum for preventing the intermediate ring 9 from being bent.

Other configurations of FIGS. 3 and 4 are the same as those of FIGS. 1 and 2, respectively. Since the thickness d of the intermediate ring 9 can be made smaller than that of the conventional one by adding the spacer 19, the height of the entire transformer is also reduced. The spacer 19 may have a cylindrical shape or generally a rod shape.

[0016]

As described above, according to the present invention, the spacer which penetrates the gap or hole of the intermediate yoke is added. As a result, the thickness of the intermediate ring in the axial direction can be reduced, so that the height of the entire transformer is reduced and the manufacturing cost is reduced.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of essential parts showing a configuration of a transformer including an intermediate yoke according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a cross-sectional view of essential parts showing the configuration of a transformer including an intermediate yoke according to a different embodiment of the present invention.

FIG. 4 is a sectional view taken along line BB of FIG.

FIG. 5 is a cross-sectional view showing the configuration of a conventional transformer provided with an intermediate yoke.

6 is a sectional view taken along line CC of FIG.

7 is a sectional view taken along line DD of FIG.

8 is a sectional view taken along line EE of FIG.

[Explanation of symbols]

1: Iron core, 2: Main leg, 3: Upper end yoke, 4: Lower end yoke, 5,50,51: Intermediate yoke, 50A: Clearance, 51
A: hole, 13, 17, 19: spacer, 8, 9: intermediate ring, 6, 7: winding, 16: gap

Claims (3)

(57) [Claims] Claim: What is claimed is: 1. Three main gears, an end yoke for magnetically connecting the main gears at both axial ends of the main gear, and between the main gears midway in the axial direction of the main gear. Equipped with an iron core composed of a magnetically connected intermediate yoke, windings for winding the main leg are arranged on both sides of the intermediate yoke, respectively, so that they are aligned with the end surface of each winding on the intermediate yoke side. An insulating intermediate ring is arranged, an insulating spacer is interposed between the intermediate rings, and an intermediate yoke is arranged in a gap between the intermediate rings formed by the spacers. A transformer with an intermediate yoke, which is characterized by the addition of a penetrating spacer. 2. The intermediate yoke according to claim 1, wherein the intermediate yoke is divided into two in a direction perpendicular to the axis to form a gap, and a spacer is passed through the gap. Transformer. 3. The transformer according to claim 1, wherein a hole is formed in the intermediate yoke, and a spacer is passed through the hole.