JPS584229A - Thermal protector - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thermal protector, in particular, a thermal protector that manually closes the gap between the electrodes after the gap between the electrodes becomes open due to a rise in ambient temperature, that is, a thermal protector that is manually returned to its original state. Regarding.

Generally, a thermal protector has a pair of open/close electrodes, consisting of a fixed electrode and a movable electrode equipped with a thermally responsive element such as a bimetal, which becomes open due to an increase in ambient temperature, and current flows to the connected load. It cuts off current and is widely used as a safety device to prevent overheating in various electrical devices.

Conventionally, manual return type thermal protectors have been fixed and
It is known that a resistance element having a positive temperature coefficient is inserted and connected between movable electrodes. To install this resistance element, insert the resistance element into a recess formed on the movable electrode side, press this resistance element with a plate spring formed on the fixed electrode side, and fix the resistance element between the movable electrodes. This was done by holding it in place.

However, the thermal protector having such a configuration has the drawbacks that the reliability of the operating temperature is low and the vibration performance is low because the resistive element is simply held between the two electrodes.

An object of the present invention is to obtain a thermal protector that has high reliability in operating temperature and high vibration resistance.

The present invention includes: a block body comprising a resistive element having a positive temperature coefficient and having two holes; two conductive sleeves each inserted into the holes of the block body and electrically contacting the block body; an electrical connection between a fixed electrode having a lead inserted into one of the sleeves and electrically contacting the sleeve, and the fixed electrode separated from the fixed electrode when a predetermined set temperature is reached; A thermal protector comprising: a thermally responsive element that opens the thermally responsive element; and a movable electrode that is electrically connected to the thermally responsive element and that is inserted into the other sleeve and has a lead that makes electrical contact with the sleeve. It is characterized by:

An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, this thermal protector has an outer diameter of 7.
It includes a container 1 made of glass with a length of 5ff, a length of 331M, and a thickness of 0.6MM, an electrode mount 2 provided inside the container 1, and dry air 3 sealed inside the container 1. Electrode mount 2 has a wire diameter of 0.7 silk and a total length of 6Lt.
A fixed electrode 4 having a lead of s wi (length of protrusion outside the glass tube: 33 mg), wire diameter of 0.7 fi, total length of 4 B,
6 ynx (length of protrusion outside the glass tube 33M), 1 node 6, sub-plate 6, longitudinal length 1011N and lateral length 5jff welded to this tip.

A movable electrode 8 having a thermally responsive element 7 made of plate-shaped pimetal μ or the like having a thickness of 0.1ff, a glass bead 9 for holding both electrodes at a predetermined distance, a diameter of 51i1° and a thickness of 2.2°.
A block body 10 consisting of a resistance element having a positive temperature coefficient (hereinafter referred to as a positive temperature coefficient thermistor) mainly composed of notrium titanate and having two holes coated with a silver film that becomes an electrode part on the curved surface M; Conductive sleeves 11.12 made of nickel with an outer diameter of 1.1 ff, a total length of 6 m (projection length from the block body of 2 am), and a thickness of 0.1 W11 are inserted into the holes of the block body 10, respectively. We are prepared.

61-1 A silver contact 13 is provided at the tip of the fixed electrode 4, and a silver alloy contact 14 is provided at the tip of the thermally responsive element 7. Furthermore, the leads of the fixed electrode 4 and the leads 6 are inserted into the sleeves 11 and 12, respectively. The container 1 is hermetically sealed at the end 16.

The thermal protector having the above structure can be obtained by the manufacturing procedure shown in FIG. 2 M to F.

The sleeves 11 and 12 shown in FIG. 2 are inserted into the holes 101L and 10b of the block body 10, respectively.

At this time, the large diameter portions 111L and 121L formed in the sleeves 11 and 12, respectively, come into contact with the edges of the holes 101L and 10b, so that the sleeves 11 and 12 close to the hole 10 of the block body 10! L and 10b by a predetermined length (FIG. 2G). Next, as shown in the second diagram, the lead of the fixed electrode 4 welded to the glass bead 9 and one end of the lead 6 are inserted into the sleeves 11 and 12, respectively, and the lead of the fixed electrode 4, the sleeve 11, and Weld the lead 6 and the sleeve 12 (see Figure 2).
Contact 13 is welded to the tip of 4, while contact 1 is welded to one end.
4 and the sub-plate portions of the thermally responsive element 7, each having the sub-plate 6 welded to the other end thereof, are welded to the sleeve 12 (FIG. 2F). The electrode mount obtained in this way is placed in a container, and after filling dry air into the container using the usual method, the ends of the container are sealed to obtain a thermal protector. FIG. 3 shows another embodiment of the present invention, in which a block body 10 made of a positive temperature coefficient thermistor is used as a glass bead. In FIG. 3, parts common to the first drawing are indicated by the same reference numerals. In FIG. 3, the other ends of the conductive sleeves 16 and 17 extend outside the block body through holes in the block body 1o, and the fixed electrode 4 and the sleeve 16 are connected to the upper and lower ends of the sleeve 16. Welding is performed at two locations, and the lead 6 and sleeve 17 are welded at two locations at the upper and lower ends of this sleeve 17. With this configuration, the leads of the fixed electrode 4 and the leads 6
There is no risk of the glass becoming misaligned, thus eliminating the need for glass beads.

4-5-F show the manufacturing procedure of the thermal protector shown in FIG. 3, which is assembled in the same manner as in FIG. 2-2. In addition, in the same figure, Figure 1,
Common parts in FIGS. 2-4 and FIG.

The thermal protector with the above configuration has the hole 10 of the block body 1o! A conductive sleeve 11.1.2 or 16.17 is inserted into L, 10b to make electrical contact with this block, and the leads of the fixed electrode 4 and the lead 6 are inserted into the sleeves 11 and 12, respectively. Since the sleeve 11 and the lead of the fixed electrode 4 and the sleeve 12 and the lead 6 are in electrical contact with each other, the electrical, thermal and mechanical relationships between the block body 1o, the fixed electrode 4 and the movable electrode 8 are The connection is reliable and therefore the operating temperature is reliable and the vibration resistance is high.

JP-A-58-4229 (3) An AC voltage of 1 is applied between the fixed electrode and the movable electrode of the thermal protector of the above embodiment shown in FIG.
When the thermal protector was tested by applying oov'6, it was found that the contacts between the two electrodes were normally open at an ambient temperature of 130"C, and then closed due to the constant temperature heat generation of the block consisting of a positive temperature coefficient thermistor. Temperature 90
A constant temperature above 'C', e.g. 1oo'C, was maintained, so that the open state between both contacts was maintained normally while a voltage was applied between both electrodes.The return of both contacts to closed state was This is done by opening the power switch.

On the other hand, a thermal protector designed for the same operating temperature as above and in which the fixed electrode and movable electrode leads are directly inserted into the hole of the block body consisting of a positive temperature coefficient thermistor without fitting the sleeve, is used under the same conditions as above. When testing with this method, it was found that the silver-coated electrode and the movable electrode or lead caused contact failure due to contact with the surface of the hole in the block body, sparking between them, and insufficient voltage being applied between them. As a result, constant temperature heat generation by the positive temperature coefficient thermistor could not be obtained, and a normal open state between the two electrodes could not be maintained. .

As explained above, the present invention has extremely good electrical, thermal, and mechanical connections between the block body made of a resistive element having a positive temperature coefficient and each electrode, and therefore has high reliability in operating temperature. , and can provide a thermal protector with high vibration resistance.

[Brief explanation of drawings]

FIG. 1 is a side sectional view of a thermal protector according to an embodiment of the present invention, FIGS. 2 M to F are perspective views showing the manufacturing process of the electrode mount of the thermal protector shown in FIG. Side sectional view of a thermal protector of another embodiment, No. 4
Figures M to F are perspective views showing the manufacturing process of the electrode mount of the thermal protector shown in FIG. 3. 1... Container, 2... Electrode mount, 4
...Fixed electrode, 6...Lead, 7...
...Thermal response element, 8...Movable electrode, 9...
...Glass bead, 10...Block body,
11.12...Sleeve. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] A block body consisting of a resistance element having a positive temperature coefficient and having two holes; two conductive sleeves each inserted into the holes of the block body and in electrical contact with the block body; and one of the sleeves. a fixed electrode having a lead inserted into the sleeve and in electrical contact with the sleeve, and separated from the fixed electrode when a predetermined set temperature is reached;
a thermally responsive element that opens the electrical connection with the fixed electrode; and a lead that is electrically connected to the thermally responsive element and inserted into the other sleeve to make electrical contact with the sleeve. A thermal protector comprising a movable electrode having a movable electrode.