JPH0541482Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to an improvement of a pellet type temperature fuse.

<Prior Art and Problems> A pellet type temperature fuse is known as one type of temperature fuse. In this pellet type temperature fuse, the movable contact material is released by releasing the compression of a compression spring, and the compression of this spring is released by melting a temperature-sensitive pellet. Therefore, the movable contact material is released by melting the temperature-sensitive pellet, and the operating temperature of the temperature fuse is determined by the melting point of the temperature-sensitive pellet.

For temperature fuses, until they operate,
Depending on the energization heat cycle of the protected electrical equipment, it is frequently heated and cooled below its operating temperature.

By the way, temperature-sensitive pellets for pellet-type temperature fuses have conventionally been made by coagulating insulating powder with a predetermined melting point with an organic binder and compression-molding it into pellets with predetermined shapes and dimensions. However, in such temperature-sensitive pellets, while the temperature fuse is frequently heated and cooled over a long period of time, the binder migrates into the insulating powder and the insulating powder changes in quality.
Its melting point may fluctuate, and under such conditions it is difficult to ensure accurate operation of the temperature fuse. However, the inventor of the present invention has found that if benzamide powder is used, it can be compression molded without a binder and can be suitably used as a temperature-sensitive pellet in the above-mentioned pellet-type temperature fuse.

<Purpose of the invention> The purpose of the invention is to eliminate the problem of deterioration of temperature-sensitive pellets due to the above-mentioned migration by using compression-molded pellets of benzamide powder, and to create pellets that can guarantee accurate operation even after a long period of time. The purpose is to provide a mold temperature fuse.

<Structure of the invention> The temperature fuse according to the invention releases the movable contact material by decompressing a compression spring, and decompresses the spring by melting a temperature-sensitive pellet. This structure is characterized in that the molded body is used as a temperature-sensitive pellet.

<Explanation of Examples> The present invention will be explained below with reference to the drawings.

In the figure, 1 is a conductive case with a lead conductor 11 provided at one end. 2 is a temperature-sensitive pellet made by compression molding only benzamide powder. 3
1 is a first pressure equalizing plate, 41 is a first spring, 32 is a second pressure equalizing plate, 5 is a movable contact member, and 6 is a fixed contact rod. Reference numeral 7 denotes a bushing through which the fixed contact rod 6 passes, and is fixed to the other end of the case by caulking the other end of the case. 8 is a sealing material. 42 is a second spring, and the movable contact member 5
and the bushing 7.

Although the temperature-sensitive pellets used in the present invention do not use a binder, they have sufficient strength and can be easily manufactured into pellet-type temperature fuses in the usual manner without damaging the temperature-sensitive pellets. . This is also clear from the following test results.

Test results Pellet type temperature fuse case inner diameter 3.4mmφ
In contrast, the outer diameter of the pellet was set to 3.3 mmφ. Also,
The length of the pellet was 2.2 mm.

The molding machine uses a punch-type tablet machine that is normally used for manufacturing pellet-type temperature fuse pellets, and only benzamide powder (mesh size 30 to 200) is poured into a cavity (thin) with an inner diameter of 3.3 mmφ.
100 benzamide pellets were produced by inserting a pellet of 4.1 mm in thickness, compressing it to a thickness of 2.2 mm with an upper punch, and then taking out this compression molded product with a lower punch at a rate of 10 times per minute. did.

When the axial compressive strength of these pellets was measured, all of them were 24 kg or more, and they could be inserted into the case of the pellet type temperature fuse without any damage.

On the other hand, we formed 100 pellets in the same manner as above using only benzyl (used after being coagulated with a binder), which is commonly used in the past, and measured the axial compressive strength of these pellets. The maximum weight was only 500g, and it was difficult to insert it into the case of a pellet-type temperature fuse without damaging it.

The above temperature fuse is used in conjunction with the electrical equipment to be protected, and due to the heat cycle of the electrical equipment,
Even thermosensitive pellets undergo repeated heating and cooling over a long period of time until they become operational.
exposed to this heating and cooling. However, since the temperature-sensitive pellets are compressed from only benzamide powder, and unlike conventional methods, the use of a binder is eliminated, it is ensured that the temperature-sensitive pellets do not change in quality due to transfer of the binder to the powder. can be prevented. Therefore, despite the long-term repeated heating and cooling described above, the melting point of the thermosensitive pellets can be maintained at the initial constant temperature, and the temperature fuse can be maintained at a temperature regulated by the melting point of the thermosensitive pellets. It can be operated accurately.

In fact, a pellet-type temperature fuse with a case inner diameter of 3.4 mmφ and a case length of 10 mm, using a compression molded body of only benzamide (melting point 128°C) as a temperature-sensitive pellet, was left in a thermostat at 120°C for one week. However, when the melting point of the temperature-sensitive pellet of the temperature fuse was subsequently measured, it was 128°C, and there was no fluctuation.

<Effects of the invention> As mentioned above, in the pellet-type temperature fuse according to the invention, since a compression molded body of only benzamide powder is used as the temperature-sensitive pellet, deterioration of the temperature-sensitive pellet due to migration can be eliminated. Accurate operation of the temperature fuse can be guaranteed even under long-term heat cycles.

[Brief explanation of the drawing]

The drawing is an explanatory diagram showing a temperature fuse according to the present invention. In the figure, 2 is a thermosensitive pellet, 41, 42
is a spring, and 5 is a movable contact material.

Claims (1)

[Scope of utility model registration request] In a temperature fuse in which the movable contact material is released by releasing the compression of a compression spring, and the compression of this spring is released by melting the temperature-sensitive pellet, a compression molded body of only benzamide powder is used as the temperature-sensitive pellet. temperature fuse.