JP2572345Y2 - Small transformer - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small transformer having a thermal fuse, which is used as a power transformer or the like built in an AC adapter.

[0002]

2. Description of the Related Art A conventional example of this type of small transformer will be described with reference to the drawings. FIG. 4 is a front view of a conventional small transformer, and FIG. 5 is a partially cutaway side view of FIG.

[0003] In the drawing, reference numeral 8 denotes a bobbin of a resin molded product. A pair of plug pins 3 are directly attached to the lower end of the bobbin 8, and a primary winding 5 and a secondary winding 4 are wound around the body. One end on the winding start side of the primary winding 5 is connected to one of the plug pins 3, while the other end on the winding end side of the primary winding 5 is connected to the other of the plug pins 3 via the thermal fuse 9. ing. Both ends of the secondary winding 4 are taken out from slits (not shown) provided at the upper end of the bobbin 8.

[0004] A polyester tape 61 is wound around the outer peripheral surfaces of the primary winding 5 and the secondary winding 4.

[0005] The thermal fuse 9 is entirely encased in a silicon glass tube 92 for insulation, and is attached along the outer peripheral surface of the secondary winding 4 by being sandwiched between the thermal fuse 9 and a polyester tape 61. .

[0006] In the figure, reference numeral 2 denotes an iron core. To assemble the core 2, a plurality of Es are inserted into the core insertion holes (not shown) of the bobbin 8.
This is performed by inserting the middle leg of the mold core, attaching a plurality of I-shaped cores to the lower end of the E-shaped core, and welding them together.

[0007]

However, when attaching the thermal fuse 9 to the bobbin 8, the thermal fuse 9 must be put in a silicon glass tube 92 and then sandwiched between the polyester tape 61. It is cumbersome and hinders cost reduction.

If the thermal fuse 9 is not completely attached to the bobbin 8 and the thermal fuse 9 is floating from the outer peripheral surface of the primary winding 5, the primary winding 5 or the secondary winding 4
When an abnormal current flows and heat is generated, heat may not be efficiently transmitted to the thermal fuse 9 and the function as the thermal fuse 9 may not be sufficiently exhibited, which poses a problem in safety measures.

Various other methods have been proposed for attaching the thermal fuse 9 to the bobbin 8 in addition to the above. However, all of these methods require a special member for fixing the thermal fuse, and at present, it is unavoidable to increase the cost.

The present invention has been made in view of the above background, and its main purpose is to make it possible to easily attach a thermal fuse to a bobbin without incurring a significant cost increase. It is an object of the present invention to provide a small transformer improved as described above.

[0011]

A small transformer according to the present invention is wound on an outer surface of a bobbin in two stages, upper and lower.
Next, it has a temperature fuse for detecting an abnormal temperature of the secondary winding, and a fuse mounting hole formed vertically through a thick portion on the side surface of the bobbin.
A first space formed in a thick portion of the secondary winding of the bobbin for mounting a main body of a thermal fuse inserted from an insertion opening formed in one end surface of the bobbin;
A second space formed in a thick portion of the next winding and taken out of a lead outlet formed on the other end surface of the bobbin through a lead wire coming out of the main body of the thermal fuse. Heat on the inner wall of the mounting hole
The configuration is such that the diameter of the fuse mounting hole is set to be smaller in the second space than in the first space in order to efficiently transmit the fuse wire .

Preferably, a thermal fuse is connected to the primary winding.
Terminal pins as relay terminals for air connection on the bobbin
Install it.

[0013] Preferably, a small device having a pair of plug pins is provided.
In the type transformer, connect the terminal pins to the
Be mounted on the bin.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a small transformer equipped with a pair of plug pins provided in an AC adapter will be described below with reference to the drawings. 1 is a perspective view of a small transformer, FIG. 2 is a partially cutaway side view, and FIG. 3 is a front view also showing a state where a thermal fuse is mounted.

In FIG. 1, reference numeral 1 denotes a bobbin which is a resin molded product, which is formed by molding a phenol resin or the like. Bobbin 1 has lower flange 11 and upper flange
12, a partition 13 and a trunk 14 (see FIG. 2).

Here, the details of the hole 15 (hole for mounting a fuse) will be described.
The structure will be described. As shown in FIG.
Vertically penetrates through the thick part of the side surface (body part 14) of the bottle 1
It is formed. That is, in the figure, 151 is one side of the bobbin 1.
For inserting the thermal fuse 7 formed on the end face of
It is the entrance. In the figure, reference numeral 152 denotes a thick portion of the secondary winding 4 of the bobbin.
And a temperature probe inserted through the insertion port 151.
This is a first space for mounting the main body of the fuse 7. Figure
The middle 152 is formed in the thick portion of the primary winding 5 of the bobbin 1.
The lead wire 71 (see FIG.
3) to the next lead outlet 154
This is the second space. 154 is the other end surface of the bobbin 1
For taking out the lead wire 71 outside.
This is the lead outlet. The diameter of the hole 15 (the hole 1 shown in FIG. 2)
5) is set as follows.
ing. That is, the diameter of the first space 152 as shown in FIG.
The dimensions are set equal to the thickness of the body of the thermal fuse 7
On the other hand, the diameter of the second space 153 is
Is set to a value corresponding to the thickness of the lead wire 71 protruding from the main body.
Have been. In short, the diameter of the hole 15 is the second
The space 153 is set smaller than the first space 152.
ing.

A pair of plug pins 3 is attached to a lower portion of the lower flange portion 11, and a terminal pin 111 for a relay terminal is attached to a side surface of the lower flange portion 11. The pair of plug pins 3 are formed with protrusions 31 for connecting to the primary winding 5 and the like, respectively.

The winding end of the primary winding 5 is wound around the projection 31 of one of the plug pins 3 and soldered. Similarly, the winding end of the primary winding 5 is wound around the terminal pin 111. It is soldered.

At the end of the upper flange portion 12, slits 16, 16, 16 for taking out both ends of the secondary winding 4 wound on the outer peripheral surface of the body portion 14 are formed, respectively.

Although not shown, the upper flange portion 12 also supports the lower surface of the power supply circuit board of the AC adapter by the surface on the slit 16 side. 2 which came out of slit 16, 16
By soldering through both ends of the secondary winding 4,
The secondary side of the small transformer is electrically connected to the circuit on the board.

An iron core insertion hole 17 is formed at the center of the bobbin 1 as shown in FIG. A hole 15 for mounting the thermal fuse 7 is provided between the body portion 14 of the bobbin 1 and the iron core insertion hole 17. In other words, this hole 15 is
14 is formed so as to penetrate in the same direction as the core insertion hole 17.

The hole 15 is shaped so that the thermal fuse 7 can be easily inserted. The dimension of the hole 15 in the short direction is set to be equal to the thickness of the thermal fuse 7.

As shown in FIG. 3, the two lead wires 71 coming out of the thermal fuse 7 are covered with an insulating Irax tube 72 and are taken out below the lower flange portion 11 through the hole 15. Have been. One end of the lead wire 71 taken out is wound around the projection 31 of the plug pin 3 and soldered, and the other end of the lead wire 71 is wound together with the end of the primary winding 5 on the winding end side. It is wound around the terminal pin 111 and soldered.

That is, the thermal fuse 7 is electrically connected in series with the primary winding 5, and the primary winding 5, the thermal fuse 7,
In connecting the pair of plug pins 3, the terminal pins 111
Are used as relay terminals.

In the figure, reference numeral 2 denotes an iron core. By inserting the middle legs of a plurality of E-shaped cores into the core insertion holes (not shown) of the bobbin 1, attaching the plurality of I-shaped cores to the lower end of the E-shaped core, and welding them together, The iron core 2 is assembled.

In the case of the small transformer configured as described above, the following various advantages can be obtained.

When the lead wire 71 of the thermal fuse 7 is passed through the hole 15 and the thermal fuse 7 is pushed into the hole 15, the outer surface of the thermal fuse 7 and the inner wall surface of the hole 15 come into contact with each other. Attached to 15. Since the thermal fuse 7 can be securely attached to the bobbin 1 only by this operation, the thermal fuse 7 can be securely attached to the polyester tape 61 as compared with the conventional case where the thermal fuse 7 is attached to the polyester tape 61.
Mounting work on the bobbin 1 is simplified.

When connecting the primary winding 5, the thermal fuse 7, and the pair of plug pins 3, the terminal pins 111 are used as relay terminals, so that the connection work is also simplified.

Further, a hole for mounting the thermal fuse 7 is provided.
15 is formed so as to penetrate the body 14 of the bobbin 1, so that the lead wire 71 of the thermal fuse 7 can be connected to the terminal pin 111 or the like through the hole 15 and, as a result, the lead wire 71 Can be hidden in the hole 15, so that the appearance of the wiring is not impaired.

On the other hand, if the abnormal current in the primary winding 5 and the secondary winding 4 generates heat flows, rises the temperature of the bobbin 1 also by the heating, the primary winding 5 and the secondary winding 4 Occur
Heat is quickly transmitted to the thermal fuse 7. That is, secondary winding
The heat generated from the wire 4 is applied to the shell 14 of the bobbin 1.
The thermal fuse directly through the thick part of the secondary winding 4
Transmitted to the 7 of the body, with the heat generated from the primary winding 5
Is the thick portion of the primary winding 5 in the body 14 of the bobbin 1;
Thermal fuse 7 through lead wire 71 of thermal fuse 7
It is transmitted to the body. In particular, regarding the diameter of the hole 15,
Space 153 is set smaller than the first space 152.
And the contact area between the thermal fuse 7 and the bobbin 1
Is sufficiently secured, so that the
Function can be fully demonstrated, and
There is a lit.

In the small transformer of the present invention, the hole 15 is formed in the bobbin 1 as a means for attaching the thermal fuse 7 to the bobbin 1. However, it is only necessary to change the design of the mold for molding the bobbin 1. , Without significantly increasing the cost.

The small transformer according to the present invention is not limited to the above embodiment with respect to the position and shape of the holes provided in the bobbin, and may be any type as long as a thermal fuse can be mounted.

[0033]

[Effect of the Invention] As described above, the small tiger according to the first aspect of the present invention is described.
In case of using a fuse, to attach a thermal fuse to the bobbin
Because it is configured to have a fuse mounting hole of
Easy installation of thermal fuse on bobbin,
Cost can be reduced. As well,
The heat generated from the primary winding or the secondary winding quickly reduces the temperature.
The configuration is such that it can be transmitted to the
The function as a dose can be sufficiently exhibited.

According to the small transformer according to the second aspect of the present invention,
The thermal fuse is electrically connected to the primary winding.
Terminal pins as relay terminals are mounted on bobbins.
Temperature, in addition to the above benefits,
The wiring work of the fuse becomes easy, and the cost
Reduction can be achieved.

According to the third aspect of the present invention, a small transformer is provided.
Terminal pin on the bobbin near the plug pin.
Since the configuration is attached, the same as in claim 2
In this way, the wiring work of the thermal fuse becomes easy,
Cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining an embodiment of a small transformer according to the present invention, and is a perspective view of the small transformer.

FIG. 2 is a partially cutaway side view of the small transformer.

FIG. 3 is a front view of the small transformer, also showing a state where the thermal fuse is mounted.

FIG. 4 is a view for explaining a conventional small transformer, and is a front view of the small transformer.

FIG. 5 is a partially cutaway side view of the small transformer.

[Explanation of symbols]

 1 bobbin 14 body 15 hole 17 core insertion hole 111 terminal pin 2 iron core 3 plug pin 4 secondary winding 5 primary winding 7 thermal fuse

Claims (3)

(57) [Scope of request for utility model registration] 1. A temperature fuse for detecting an abnormal temperature of primary and secondary windings wound on an outer surface of a bobbin in two upper and lower stages, and penetrating vertically through a thick portion on a side surface of the bobbin. And a fuse mounting hole formed in the thick portion of the secondary winding of the bobbin and a temperature inserted from an insertion opening formed in one end surface of the bobbin. A first space for mounting the fuse body, and a lead hole formed in the thick portion of the primary winding of the bobbin and formed on the other end surface of the bobbin through a lead wire coming out of the temperature fuse body. It is composed of a second space for taking out from the outlet, the inner wall surface of the hole for the fuse mounting heat
Characterized in that the second space is set smaller than the first space with respect to the diameter of the fuse mounting hole so as to efficiently transmit to the lead wire . 2. The small transformer according to claim 1, wherein a terminal pin serving as a relay terminal for electrically connecting the thermal fuse to the primary winding is mounted on the bobbin. 3. The small transformer according to claim 2, wherein the terminal pin is mounted on a bobbin near the plug pin in a small transformer having a pair of plug pins.