JP2002118023A - Covered small transformer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an small transformer which is equipped with a cover and keeps a sufficient creeping distance between a terminal and a core, capable of lowering its height, even if it is required to widen a winding part or to narrow a pin pitch. SOLUTION: A covered small transformer is equipped with a cover 6, mounted on the primary coil side of a coil bobbin 2, a bobbin side insulating wall 5 protruding outwards so as to increase a creeping distance is provided to the upper part of the terminal 1 of the primary coil side of the coil bobbin 2, and the cover 6 is so shaped as to house the bobbin-side insulation wall 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compact transformer used for consumer electronic equipment, for example, an audio amplifier, and more particularly, to a pin terminal type transformer having improved insulation between a core and a pin terminal. For small transformers with

[0002]

2. Description of the Related Art Conventionally, as this type of transformer, for example, there is a transformer as shown in FIG. That is, in the figure, 20 is a coil bobbin, 21 is an L-shaped pin-shaped terminal 22.
, A terminal portion of the coil bobbin 20 in which is implanted, 23 is a core incorporated in the coil bobbin 20, and 24 is a coil bobbin 2
A cover made of an insulating resin to be attached to the terminal 0, and formed between the bent portion 22a of the terminal 22 and the core 23 so that an insulating wall 24a in the form of a partition wall is located for obtaining insulation. I have.

However, in the case of a small-sized transformer, there is a problem that it is difficult to reduce the size of the transformer in order to secure a sufficient creepage distance between the bent portion 22a and the core 23.

That is, the creepage distance between the bent portion 22a and the core 23 is determined by the dimensions a (about 4 mm), b (about 2 mm), and c (about 2 mm) along the outer surface of the coil bobbin 20 therebetween. However, if the height is reduced to reduce the size, the gap between the core 23 and the bent portion 22a of the terminal 22 is reduced, so that the required creepage distance cannot be sufficiently secured, and the insulation resistance is reduced. There is a drawback that the property may be lacking.

To solve the above-mentioned disadvantage, there is Japanese Patent Application Laid-Open No. 11-297535 filed by the applicant of the present invention.

FIG. 13 shows the small transformer. According to this small-sized transformer, in the small-sized transformer with a cover of a type in which a cover is provided on the coil bobbin, the groove 4 for increasing the creepage distance in the terminal portion 1 in which the terminal 3 of the coil bobbin 1 is planted
And an insulating wall 6b to be inserted into the groove 4 inside the cover 6, the terminal 3 is located below the insulating wall 6b, and the core 12 incorporated into the coil bobbin 1 is located above the insulating wall 6b. Thus, the insulation between the core 12 and the terminal 3 is improved.

[0007]

However, in this small transformer, if the dimension A is increased in order to widen the winding portion or the dimension B of the pin pitch between the pin terminals is reduced, depending on the design conditions, the insulating wall is not formed. There has been a problem that the C dimension is reduced, the creepage distance cannot be secured, and the height of the transformer cannot be reduced.

[0008] The present invention has been proposed in view of the above, and its purpose is to expand the winding portion,
It is an object of the present invention to provide a small-sized transformer capable of securing a creepage distance between a core and a terminal without affecting the dimensions of the insulating wall 6b shown in FIG. 13 even when the pin pitch dimension needs to be reduced. It is the purpose.

[0009]

SUMMARY OF THE INVENTION The present invention relates to a small transformer with a cover of the type in which a cover 6 is mounted on the primary coil side of a coil bobbin 2, wherein the transformer is provided above a terminal portion 1 on the primary coil side of the coil bobbin 2. The above object is achieved by protruding the bobbin-side insulating wall 5 for increasing the creepage distance and forming the cover 6 into a shape capable of storing the bobbin-side insulating wall 5. In this case, a feature is that a window 6d is formed in the cover 6 so that the bobbin-side insulating wall 5 can protrude to the outside. Further, a groove 4 for increasing the creepage distance is formed in the terminal portion 1 of the coil bobbin 2, and a cover-side insulating wall 6b inserted into the groove 4 is formed on the cover 6 side.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, a bobbin-side insulating wall 5 for increasing a creepage distance is formed above a terminal portion 1 on a coil bobbin 2 side, and the bobbin-side insulating wall 5 is protruded outward and has a length. Because there is a degree of freedom in setting, it is possible to respond to changes in specifications.

[0011]

[Embodiment 1] FIG. 1 is a sectional view showing a main part of the present invention. 1 in the figure
Is a thick terminal portion formed on the coil bobbin 2, 3 is a substantially L-shaped pin terminal implanted in the terminal portion 1, 4 is a groove formed in the terminal portion 1, 5 is an upper portion of the groove 4. The bobbin-side insulating wall protrudes outward, and the groove 4 and especially the bobbin-side insulating wall 5 are formed to increase the creepage distance.

Reference numeral 6 denotes a cover made of an insulating resin mounted on the coil bobbin 2. This cover 6 is a pin terminal 3
Outer wall 6a disposed opposite to the lead wire binding portion 3a side
A cover-side insulating wall 6b which is bent in a direction perpendicular to the outer wall 6a and whose inner end is inserted into the groove 4, and a bobbin-side insulating wall 5 formed above the cover-side insulating wall 6b.
And a window 6d for a bobbin-side insulating wall formed between the upper wall 6c and the cover-side insulating wall 6b.

According to the present invention, the bobbin-side insulating wall 4 is provided so as to protrude outward above the terminal portion of the coil bobbin 2, so that the transformer height can be reduced even if the dimensions A and B shown in FIG. The creepage distance can be secured by the length dimension of the surface of the bobbin-side insulating wall 5 in a state where the height is lowered.

That is, the creepage distance corresponds to the length of the bobbin-side insulating wall 5, and the bobbin-side insulating wall 5 is used for the bobbin-side insulating wall according to the necessity of the specification as shown by a virtual line in FIG. It is also possible to protrude outward from the window 6d and lengthen it, or conversely shorten it. In this way, by appropriately adjusting the length of the bobbin-side insulating wall 5 at the time of design, a desired creeping surface can be obtained. A distance can be secured.

FIG. 2 is a partial perspective view of the terminal portion 1 and the cover 6 of the coil bobbin 2, and members corresponding to those in FIG. 1 are denoted by the same reference numerals.

3 to 6 are front views of the cover 6, respectively.
A bottom view, side view, and rear view are shown.

Next, the structure of the cover 6 will be described with reference to these drawings.

The cover 6 has an outer surface of the primary coil 8 wound around the outer periphery of the winding drum 7 of the coil bobbin 2 and a flange 9 formed on one side of the coil bobbin 2 as shown in FIG. Cover body 6 covering intermediate flange 10
e, a substantially box-shaped terminal projecting below one side of the cover main body 6e and covering a portion of the thick terminal portion 1 bulging outward below one side surface of the flange 9. And a unit cover 6f. In this case, the cover body 6
e is partially open at the bottom and back. The terminal cover 6f includes an outer wall 6a, a cover-side insulating wall 6b, and a window 6.
d, the upper wall 6c, etc., and the bottom is open.

The cover body 6e includes a top plate 6g, an end plate 6h,
The side plate 6i is formed with a window 6j, as shown in FIG. The position of this window 6j,
The shape corresponds to the window 11 for inserting the center leg of the core formed on the flange 9 of the coil bobbin 2 as shown in FIGS.

Further, the terminal cover 6f is provided with the terminal cover 6f shown in FIGS.
As shown in FIG. 6, the length is longer than the width of the cover body 6e, and covers the terminal portion 1 having the terminal 3, and has a substantially corresponding shape.

The terminal cover 6f has an end wall 6h formed beside the upper wall 6c and the outer wall 6a. As shown in FIG. 1, FIG. 2, FIG. 3, FIG.
8 has a bent portion having a substantially inverted L-shape in vertical cross section, which protrudes outward from the lower side of the flange 9 shown in FIG. 8 and covers the upper portion of the terminal portion 1, and a window 6d is formed in this portion.

FIGS. 7 and 8 are a front view and a side view of the coil bobbin 2 used in combination with the cover 6.

As described above, the coil bobbin 2 has a hollow winding drum 7 and flanges 9, 9 formed at both ends thereof.
And a terminal portion 1 swelled below each of the funnels 9 and 9 and having terminals 3 implanted thereon, and formed between the flanges 9 and 9 at both ends, and a primary coil 8 and a secondary coil 12 are formed. And primary and secondary coils 8 and 12 are wound on the winding drum 7 as shown by imaginary lines, respectively, and are formed of an insulating resin. The lead wires of those coils are drawn out and wrapped around the root of the bent portion 3a of the predetermined terminal 3, as is well known,
Soldering is performed via a soldering device.

In assembling, as shown in FIG.
The cover 6 may be positioned on the primary coil 8 side of the coil bobbin 2 where the voltage is high, and mounted so as to cover as shown in FIG. In this case, the terminal portion cover 6f of the resin cover 6 is deformed so as to be lifted slightly upward to cover the terminal portion 1. However, since the terminal portion cover 6f has an inverted U-shaped groove a. Easy to deform, good workability. In FIG. 10, reference numeral 13 denotes a coil bobbin 2
2 shows the core incorporated in FIG.

In this state, as shown in FIG.
The cover insulating wall 6 on the cover 6 side is provided in the groove 4 of the coil bobbin 2.
The inner end of b is inserted.

The bobbin insulating wall 5 on the coil bobbin 2 side is inserted into the window 6d on the cover 6 side.

As a result, the length of the distance b shown in FIG. 12 can be increased from 2 mm to 6 mm or more because the bobbin-side insulating wall 5 is formed in addition to the cover-side insulating wall 6b, and the height dimension is increased. The distance between the terminal bent portion 3a and the core 12 along the surface of the coil bobbin 2, that is, the creepage distance can be increased without increasing the height.

In this case, the terminal bent portion 3a and the core 1
2, the upper wall 6c of the cover 6, the insulating wall 6b on the cover side
Since the bobbin-side insulating wall 5 and the like are interposed, the insulation between the terminal bent portion 3a and the core 12 can be further improved.

[0029]

Embodiment 2 FIG. 11 shows a second embodiment of the present invention. This embodiment is characterized in that the cover 6 is formed with a storage portion 6A for storing the substantially cylindrical bobbin-side insulating wall 5 having an open front. Thus, the shape of the cover 6 is not limited to the shape of the first embodiment. Also, it is needless to say that various changes can be made to the shape of the coil bobbin 2 without departing from the spirit of the present invention.

[0030]

As described above, according to the present invention, since the bobbin insulating wall 5 is formed on the coil bobbin 2, the creepage distance can be secured without increasing the height of the transformer regardless of the design conditions of the small transformer.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a first embodiment of the present invention.

FIG. 2 shows a partial perspective view of a main part of the present invention.

FIG. 3 is a front view of a cover used in the first embodiment of the present invention.

FIG. 4 is a bottom view of the above.

FIG. 5 is a side view of the same.

FIG. 6 is a rear view of the above.

FIG. 7 is a front view of a coil bobbin used in the first embodiment of the present invention.

FIG. 8 is a side view of the same.

FIG. 9 is an explanatory view of an assembled state of the present invention.

FIG. 10 is an explanatory view of the assembly completed state of the present invention.

FIG. 11 is a partial perspective view of a main part of a second embodiment of the present invention.

FIG. 12 is an explanatory view of a conventional example.

FIG. 13 is an explanatory diagram of a conventional example corresponding to the prior art of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Terminal part 2 Coil bobbin 3 Pin terminal 3a Lead wire binding part 4 Groove 5 Bobbin side insulating wall 6 Cover 6a Outer wall 6b Cover side insulating wall 6c Top wall 6d Window 6e Cover body 6f Terminal cover 6g Top plate 6h End plate 6i Side wall 6j Window 7 Ticket body 8 Primary coil 9 Flange 10 Intermediate flange 11 Window for inserting the center leg of core 12 Secondary coil 13 Core

Claims (3)

[Claims] 1. A small-sized transformer with a cover in which a cover (6) is mounted on a primary coil side of a coil bobbin (2), wherein the transformer is provided above a terminal (1) on a primary coil side of the coil bobbin (2). A bobbin-side insulating wall (5) protruding outward to increase the creepage distance, and a cover (6) is formed in a shape capable of storing the bobbin-side insulating wall (5). Trance. 2. A small transformer with a cover according to claim 1, wherein a window (6d) is formed in the cover (6) so that the bobbin-side insulating wall (5) can protrude to the outside. 3. The coil bobbin (2) according to claim 1, wherein a groove (4) for increasing a creepage distance is formed in the terminal portion (1) of the coil bobbin (2), and the groove (4) is formed on the cover (6) side. A small transformer with a cover, wherein a cover-side insulating wall (6b) to be inserted is formed.