JPH10189309A - Overcurrent protection device - Google Patents

Abstract

(57) [Problem] To provide an overcurrent protection device that protects a PTC element, improves heat dissipation, and can quickly resume operation. SOLUTION: The PCT element 1 having electrodes 2a, 2b provided with connection terminals 2a ', 2b' attached to both surfaces.
An upper cover 3 internally provided with ribs 4a and 4b for tightly sandwiching the two electrode surfaces to protect the PTC element, and two connection terminals provided on the electrode and an external connection And a lower cover 5 provided with a means for connecting and fixing the terminal (7).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an overcurrent protection device for protecting an overcurrent flowing through a load.

[0002]

2. Description of the Related Art Conventionally, a PTC element, which exhibits a low resistance value at a normal temperature and whose resistance value rapidly increases with temperature at a certain temperature or higher, is inserted and connected between an electric component as a load and a power supply. An overcurrent protection device that protects an overcurrent from flowing into electrical components is known.

FIG. 2 shows an overcurrent protection device disclosed in Japanese Patent Application Laid-Open No. 7-91356. 20 is PTC
Electrodes 23 and 24 having connection terminals 23a and 24a are attached to both surfaces of the element. A lower case 22 has a pair of holes 22b formed on the bottom surface thereof.
b, the terminals 23a and 24a are inserted and
By fitting the female terminal 27 of the terminal of the connection wire 26 into the terminals a and 24a, the terminals are electrically connected and the PTC element is fixed. Incidentally, 21 is an upper cover for protecting the PTC element 20, and 22a is a mounting member.

[0004]

As described above, in the conventional overcurrent protection device, the PTC element 20 has the upper cover 2 and the lower cover 2.
They were housed in the insides of the devices 1 and 22 for protection. For this reason, an overcurrent flows through the electrical components and the like connected to the overcurrent protection device, and the PTC element 20 generates heat to increase the temperature. When the overcurrent protection is performed, the PTC element 20 is housed in the cover. Therefore, it takes a long time to dissipate the generated heat and reach a steady temperature, and it takes a long time to restart the operation.

[0005] As a method of shortening the time until the operation is restarted, for example, as shown in FIG. Japanese Patent Laid-Open Publication No. Sho 62-163902 discloses a method for improving the above. In this method, the heat dissipation is good, but the PTC element 3
Since 0 is not protected, it may be damaged by external contact or the like. Here, 31b and 32b are lead wires.

[0006] The present invention has been made in view of the above problems, and protects a PTC element and improves heat dissipation.
An object of the present invention is to provide an overcurrent protection device that can immediately resume operation.

[0007]

According to a first aspect of the present invention, there is provided an overcurrent protection device for protecting an overcurrent flowing through a load, wherein an electrode having a connection terminal is provided. A PCT element mounted on both sides and the PT
In order to protect the C element, there is provided an upper cover provided with a rib for holding the both electrode surfaces in close contact with each other, and a means for connecting and fixing both connection terminals provided on the electrode and an external connection terminal. And a lower cover provided. Further, in the second invention, a rib for closely sandwiching the two electrode surfaces is provided on the lower cover instead of the upper cover.

A PTC element having electrodes provided with connection terminals on both sides is tightly held by ribs provided on an upper cover or a lower cover, so that heat accumulated in the PTC element and the electrodes is reduced. Is transmitted to the upper cover or the lower cover through the rib, and is radiated to the outside through the cover. Therefore, heat dissipation is improved, and the time until the operation is restarted can be shortened. The rib is PTC
Since the element is sandwiched, it is possible to prevent the PTC element from falling off due to vibration or the like. Further, heat dissipation is improved, so that the current carrying capacity can be increased.

[0009]

FIG. 1 shows an example of an embodiment of the present invention.
This will be described with reference to FIG. FIG. 1A is an exploded perspective view of the overcurrent protection device according to the present invention, with part cutaway, and FIG.
(C) is a sectional view taken along line YY of (A). In FIG. 1, reference numeral 1 denotes a PTC element, and electrodes 2a and 2b having terminals 2a 'and 2b' provided alternately at lower ends are attached to both surfaces thereof.

Reference numeral 3 denotes an upper cover for protecting the PTC element 1, and provided on its inner surface with ribs 4a and 4b for closely holding the electrodes 2a and 2b of the PTC element 1. In FIG. 1, the ribs 4a and 4b correspond to the electrodes 2a.
And 2b, but it is desirable that the size be close to the entire surface.

A lower cover 5 is provided with a pair of terminal insertion holes 6a and 6b in an inner bottom 5a thereof so that the terminals 2a 'and 2b' of the PTC element 1 can be inserted therein. . In the lower space of the middle bottom 5a of the lower cover 5, female terminals 7 as external connection terminals fixed to the electric wires 8a and 8b, respectively, are accommodated.
a and terminals 2 of electrodes 2a and 2b projecting from 6b
a 'and 2b'.

Next, the assembly of the overcurrent protection device will be described. First, the PTC element 1 to which the electrodes 2a and 2b are attached is inserted between the ribs 4a and 4b of the upper cover 3 and clamped. Next, when the upper cover 3 is pressed over the lower cover 5, the terminals 2a 'and 2b'
Through the terminal insertion holes 6a and 6b, the tip of which protrudes below the midsole 5a. Then, the female terminals 7 of the terminals of the electric wires 8a and 8b are inserted. Thereby, the PTC element 1 is fixed in the upper and lower covers 3 and 5 and the external electric wire 8
a, 8b.

The upper cover 3 and the ribs 4a and 4b are made of PP,
It is made of PBT or the like, and is made of a plastic having good heat conductivity by adding a heat conduction imparting agent such as silica or boron nitride.
When the upper cover 3 and the ribs 4a and 4b are made of a metal material having good heat conductivity, an insulating thin film having good heat conductivity is formed on the surfaces of the electrodes 4a and 4b by resin processing or the like. With this configuration, the heat generated by the PTC element 1 is transferred to the upper cover 3 via the electrodes 2a and 2b and the ribs 4a and 4b.
And is radiated from the upper cover 3.

In the embodiment, the electric wire 2a of the PTC element 1 is used.
The ribs 4a and 4b sandwiching the
Is provided on the inner surface of the top plate.
a and 6b may be provided on the inner surface of the insole 5a or the side wall.

[0015]

As described above, according to the present invention, the following effects can be obtained. A PTC element having electrodes provided with connection terminals on both sides is closely held by a rib provided on an upper cover or a lower cover.
The heat stored in the C element and the electrode is transmitted to the upper cover or the lower cover via the rib, and is radiated to the outside via the cover. Therefore, heat dissipation is improved, and the time until the operation is restarted can be shortened. Further, since the ribs sandwich the PTC element, it is possible to prevent the PTC element from falling off due to vibration or the like. Further, heat dissipation is improved, so that the current carrying capacity can be increased.

[Brief description of the drawings]

1A is a partially cutaway exploded perspective view of an embodiment of the present invention, FIG. 1B is a sectional view taken along line XX of FIG. 1A, and FIG. 1C is a sectional view taken along line YY of FIG. It is sectional drawing.

FIG. 2 is a configuration diagram of a conventional example.

FIG. 3 is a configuration diagram of a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 PTC element 2a, 2b Electrode 2a ', 2b' Terminal 3 Upper cover 4a, 4b Rib 5 Lower cover 6a, 6b Hole 7 Female terminal 8a, 8b Electric wire

Claims (2)

[Claims] An overcurrent protection device for protecting an overcurrent flowing through a load, wherein a P-type electrode having terminals for connection is mounted on both sides.
A CT element, an upper cover provided with a rib for tightly sandwiching the two electrode surfaces to protect the PTC element, and a connection terminal and an external connection terminal provided on the electrode. An overcurrent protection device, comprising: a lower cover provided with a connection fixing means. 2. The overcurrent protection device according to claim 1, wherein a rib for closely sandwiching the two electrode surfaces is provided on the lower cover instead of the upper cover.