JP3430144B2 - Small transformer with cover - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a consumer electronic device, for example, a small transformer used for an audio amplifier, and more particularly to a pin terminal type transformer, which has a cover with improved insulation between the core and the pin terminal. About small transformer with

[0002]

2. Description of the Related Art Conventionally, as a transformer of this type, there is one shown in FIG. 12, for example. That is, in the figure, 20 is a coil bobbin, 21 is an L-shaped pin-shaped terminal 22
The terminal portion of the coil bobbin 20 in which is embedded, 23 is a core incorporated in the coil bobbin 20, and 24 is the coil bobbin 2
It is a cover made of an insulative resin that is mounted on the terminal 0, and is formed so that a partition wall-shaped insulating wall 24a is located between the bent portion 22a of the terminal 22 and the core 23 to obtain insulation. There is.

However, in a small transformer, there is a problem that it is difficult to reduce the size of the transformer if it is attempted 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 based on the a dimension (about 4 mm), the b dimension (about 2 mm), the c dimension (about 2 mm) along the outer surface of the coil bobbin 20 between them. Although it is formed, when the height is reduced to reduce the size, the gap between the core 23 and the bent portion 22a of the terminal 22 also becomes small, so that the required creepage distance cannot be secured and insulation resistance is increased. There was a drawback that it lacked in some cases.

As a solution to the above-mentioned drawbacks, there is Japanese Patent Application Laid-Open No. 11-297535 filed by the applicant of the present application.

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

[0007]

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

The present invention has been proposed in view of the above, and its object is to widen the winding portion,
Even when it becomes necessary to reduce the pin pitch size, it is possible to provide a small transformer that can secure the creepage distance between the core and the terminal without affecting the size of the insulating wall 6b shown in FIG. It is intended.

[0009]

SUMMARY OF THE INVENTION The present invention is 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, and is provided on an upper portion of a terminal portion 1 on the primary coil side of the coil bobbin 2. The above-mentioned object is achieved by projecting the bobbin side insulating wall 5 for increasing the creepage distance and forming the cover 6 into a shape capable of accommodating the bobbin side insulating wall 5. Further, in this case, it is characterized in that the cover 6 is formed with a window 6d capable of projecting the bobbin side insulating wall 5 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]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, a bobbin-side insulating wall 5 for increasing a creepage distance is formed on an upper portion of a terminal portion 1 on the coil bobbin 2 side, and the bobbin-side insulating wall 5 is protruded outwardly and has a length. Since there is a degree of freedom in setting, it is possible to respond to changes in specifications.

[0011]

[Embodiment 1] FIG. 1 shows a cross-sectional view of an essential part of the present invention. 1 in the figure
Is a thick-walled 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, and 5 is an upper portion of the groove 4. Which is a bobbin side insulating wall formed on the outer side of the bobbin side, and the groove 4 and particularly the bobbin side insulating wall 5 are formed to increase the creeping distance.

Reference numeral 6 is a cover made of insulating resin that is mounted on the coil bobbin 2. This cover 6 is a pin terminal 3
6a of the outer wall that is arranged to face the leader wire entanglement portion 3a side
And a cover-side insulating wall 6b bent in a direction orthogonal to the outer wall 6a and having an inner end inserted into the groove 4, and a bobbin-side insulating wall 5 formed above the cover-side insulating wall 6b.
And an upper wall 6c positioned on the upper part of the above, and a window 6d for the bobbin side insulating wall formed between the upper wall 6c and the cover side insulating wall 6b.

In the present invention, the bobbin-side insulating wall 4 is provided so as to project 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. 13 are reduced. 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, this creepage distance corresponds to the length of the bobbin-side insulating wall 5, and the bobbin-side insulating wall 5 is for the bobbin-side insulating wall according to the necessity of specifications as shown by a phantom line in FIG. The window 6d may be projected outward to make it longer, or conversely, it may be made shorter. By appropriately adjusting the length of the bobbin side insulating wall 5 at the time of designing in this way, a desired creeping surface can be obtained. The distance can be secured.

FIG. 2 is a partial perspective view of the terminal portion 1 of the coil bobbin 2 and the cover 6, and the 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, a side view, and a 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 circumference of the winding body portion 7 of the coil bobbin 2 shown in FIG. 8 and a flange 9 side formed on one side of the coil bobbin 2. Cover body 6 covering the intermediate flange 10 part
e, and a substantially box-shaped terminal projecting below one side of the cover body 6e and covering a portion of the thick-walled terminal portion 1 that is bulged outward at the lower side of one side surface of the flange 9. And a partial cover 6f. In this case, the cover body 6
The bottom part and the back surface of e are open. 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, end plates 6h,
A window 6j is formed on the side plate 6i, as shown in FIG. The position of this window 6j,
The shape corresponds to the window 11 for inserting the central leg of the core formed in the flange 9 of the coil bobbin 2 as shown in FIGS. 7 and 8.

Further, the terminal portion cover 6f has a structure as shown in FIGS.
As shown in FIG. 6, the size 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 laterally to the upper wall 6c and the outer wall 6a. As shown in FIGS. 1, 2, 3, 5 and the like, the upper wall 6c has a structure shown in FIG.
Further, there is a bent portion which projects from the lower portion of the flange 9 shown in FIG. 8 to the outside in the side direction thereof and covers the upper portion of the terminal portion 1 and which has a substantially L-shaped vertical cross section, and a window 6d is formed in this portion.

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 barrel portion 7 and flanges 9 and 9 formed at both ends thereof.
And a terminal portion 1 that is bulged outside the respective funnels 9 and 9 and in which terminals 3 are planted, and is formed between the flanges 9 and 9 at both ends, the primary coil 8 and the secondary coil 12 Is formed of an insulating resin, and, as is well known, primary and secondary coils 8 and 12 are respectively wound on the winding barrel 7 as shown by phantom lines, The lead wires of those coils are drawn to the outside and, as is well known, are entangled at the root of the bent portion 3a of the predetermined terminal 3,
Soldered through a soldering device.

Upon assembly, as shown in FIG.
The cover 6 may be located on the primary coil 8 side of the coil bobbin 2 having a high voltage, and may be mounted so as to cover the coil bobbin 2 as shown in FIG. In this case, the terminal cover 6f of the resin cover 6 is slightly lifted upward to be deformed so as to cover the terminal 1, but since the terminal cover 6f has an inverted U-shaped groove a. , Easy to deform and good workability. In FIG. 10, 13 is the coil bobbin 2.
Shows the core embedded in.

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.

Further, 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 along the surface of the coil bobbin 2 between the terminal bent portion 3a and the core 12, that is, the creepage distance can be increased without increasing the height.

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

[0029]

Second Embodiment FIG. 11 shows a second embodiment of the present invention. This example is characterized in that the cover 6 is provided 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. Further, it goes without saying 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 side, the creeping distance can be secured without increasing the height of the transformer regardless of the design condition of the small transformer. In this case, bobbin side insulating wall 5
To the outside from the bobbin side insulating wall window 6d
It is also possible to shorten it to the contrary.
By adjusting, a desired creepage distance can be secured.

[Brief description of drawings]

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

FIG. 2 shows a partial perspective view of an essential 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 same.

FIG. 5 is a side view of the above.

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 above.

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

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

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

FIG. 12 is an explanatory diagram 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]

1 terminal 2 coil bobbins 3-pin terminal 3a Leader wire binding part 4 grooves 5 Bobbin side insulation wall 6 cover 6a outer wall 6b Cover side insulation wall 6c Upper 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 Window for inserting the central leg of the 11 core 12 Secondary coil 13 cores

Claims (2)

(57) [Claims] 1. A small transformer with a cover in which a cover (6) is mounted on the primary coil side of a coil bobbin (2), the upper part of a terminal portion (1) on the primary coil side of the coil bobbin (2). A bobbin-side insulating wall (5) protruding toward the outside for increasing the creepage distance is provided so that the cover (6) has a shape capable of accommodating the bobbin-side insulating wall (5), and the bobbin is attached to the cover (6). Side insulation wall
A small transformer with a cover, characterized in that a window (6d) capable of projecting (5) to the outside is formed . 2. The groove according to claim 1, wherein a groove (4) for increasing the creepage distance is formed in the terminal portion (1) of the coil bobbin (2), and the groove (4) is formed in the groove (4) on the cover (6) side. A small transformer with a cover, characterized in that an insulating wall (6d) on the cover side to be inserted is formed.