JPS597714Y2 - Overheat protector for wire wheels - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to an improvement of a desuperheater for wire wheels.

Overheating of coils in transformers, electric coils, electric motors, electromagnets, ballasts, etc., if left untreated, can lead to major accidents such as fires, so there is a tendency for stricter regulations to be put in place for safety reasons.

As a countermeasure, the inventor has registered utility model No. 11365.
No. 81 (1975 Utility Model Application Publication No. 38748)
In this paper, we proposed a new overheat protector to replace the conventional thermal fuse and thinning of some of the windings.

The structure is such that a solder alloy is spread between the ends of two approximately parallel lead wires and joined together, and the ends of the lead wires containing the solder alloy are wrapped in a flat insulating coating.

According to this overheating preventer, its small size and flatness allow it to be freely installed inside the wire ring, and the handling and manufacturing thereof can be made easy and inexpensive.

In addition, when in use, if the axis of the solder alloy is attached to the wire so that it is parallel to the winding, and if it is electrically connected in series with this, it will be possible to prevent the wire from overheating due to excessive current. , the solder alloy melts within the flat insulation coating, and since the axis of the solder alloy is located parallel to the winding and crosses the magnetic flux at right angles, the melted solder alloy is exposed to the alternating current flowing through the wire. The current and alternating magnetism cause vibrations, and the surface tension gradually narrows and separates the offshore core.

Therefore, compared to conventional overheating prevention means, it has become possible to cut off the circuit at a set temperature much more accurately.

However, in this overheating preventer, the upper and lower sides of the solder alloy are directly held together like a sandwich with adhesive tape, so
For example, if the wire to be applied is of a ring core type, where the direction and strength of leakage magnetism varies, or if the wire is of a type with weak AC magnetism overall, the vibration effect of the solder alloy may be affected. There are concerns that it will become weaker.
Furthermore, since the space in which the solder alloy is scattered when the solder alloy is fused due to vibration is small, there is a problem in the uniformity of electrical insulation.

The present invention is an attempt to further improve the conventional overheating preventer described above, and it not only attaches multiple lead wires and connects the heat-sensitive elements between the ends of the lead wires, but also connects the lead wires with each other. A unit with a heat-sensitive element is attached to a base piece made of an electrically insulating material, and a recess is formed on the surface of the base between the lead lines near the heat-sensitive element, and the magnetic piece is accurately positioned by this recess. In addition, a recess is formed on one side of the base immediately below the heat-sensitive element to accommodate at least a longitudinally intermediate portion of the heat-sensitive element, thereby making the vibration torque of the heat-sensitive element strong and efficient. This makes it possible to accurately and reliably interrupt the circuit at the set temperature even if the magnetic direction is random or the wire is weakly magnetic, and furthermore, the recessed part allows the scattered heat-sensitive element particles to be collected after fusing. This feature is characterized in that the heat-sensitive element is prevented from being re-welded after being fused and becomes energized.

Examples of the present invention will be described below based on the attached drawings.
1 to 4 show one embodiment of the desuperheater of the present invention, and FIGS. 5 and 6 show another embodiment, in which a base piece 1 made of an electrically insulating material has a A plurality of almost parallel lead wires 2, 2 are attached, and a linear or pin-shaped heat-sensitive element 3 made of solder alloy or the same easily melted metal is attached between the tips of the lead wires 2, 2 in the form of a bridge. The contact points of the heat-sensitive elements 3 and the lead wires 2, 2 are joined, and the base piece 1 has a lead-out line 2 near the heat-sensitive element 3.
, 2 is formed with a recess 4.

This recess 4 may have a bottom that does not penetrate through the thickness direction of the base piece 1 as shown in FIGS. The recess 4 may be a full-length window hole, and in either case, a magnetic piece 5 made of a material such as iron or nickel is attached (fitted) to the recess 4.

Furthermore, a recess 6 is formed in the base piece 1 at a position directly below the heat-sensitive element 3.

The recess 6 may be a window hole that reaches the front and back surfaces of the base piece 1 as shown in the figure, but may be a depression that does not reach the back surface of the base piece 1 depending on the case.

In either case, the lead wires 2, 2 and the heat-sensitive element 3
A flat insulating coating 7 is provided around the base piece 1 including the magnetic piece 5.

Here, the shape of the recess 6 is arbitrary, and the width of the short side thereof is preferably at least twice the diameter of the heat-sensitive element 3.

On the other hand, as for the width on the long side, it is necessary to minimize it and include the middle part in the length direction as shown in Figure 7A, but the upper limit is set by the lead line 2, as shown in Figure 7A. 2
Alternatively, as shown in FIG. 7C, it may be shaped to cross the lead lines 2, 2 and extend over the entire length of the heat-sensitive element.

Next, the base piece 1 is not particularly limited as long as it is an electrically insulating material.

For example, insulating papers such as press pods and press pans,
A thin plate made of resin such as vinyl chloride or polyethylene, a thin plate made of glass fiber, or a thin rubber plate may be used.

Among these, when the base piece 1 is made of a flexible material such as rubber, its moderate flexibility allows it to fit better into the attachment part within the wire ring, resulting in very good adhesion to the winding wire. be able to.

Next, the insulating coating 7 may be an insulating paper or insulating tape with an adhesive surface formed on the surface (Fig. 1), a thermoplastic synthetic or resin tube (Fig. 5), or The resin coating may be formed by a molding method, a dipping method, or a spraying method.

In any case, this insulating coating 7 needs to cover the entire circumference of the base piece 1 if the recess 4 or the recess 6 is a window hole. When the base piece 1 has a so-called bottomed shape, it may be applied only to the surface of the base piece 1 (the side to which the leader line or the heat-sensitive element is attached).

On the other hand, the magnetic piece 5 may be arranged only on one side with respect to the heat-sensitive element 3 as shown in FIGS. 1 to 4.
As shown in FIG. 5, the heat-sensitive element 3 may be sandwiched and disposed on both sides thereof, or, although not shown, each side may have a plurality of heat-sensitive elements instead of one.

Further, it is preferable that the heat-sensitive element 3 is located inside the surface of the recess 6, and a method for achieving this is to form a groove 8 in the base piece 1 at the attachment position of the lead wires 2, You may take a method of reducing the height of 2, 2, or add insulation coating 7.
After providing the lead wires 2, 2 by rolling pressure with rollers etc.
A method may also be used in which the heat-sensitive element 3 is pushed into the recess 6 while being compressed a little.

To explain the usage and operation of the desuperheater of the present invention, which has the above-mentioned structure, the desuperheater of the present invention has the structure of Medium or 2
It is installed at any position, such as between the layers of the next winding, so that the heat-sensitive element 3 is positioned parallel to the winding, and it is electrically connected in series with the coil by lead wires 2, 2. It is.

In this way, the desuperheater can be installed in a manner that does not create a temperature difference between the wire and the winding at the highest temperature point in the wire.

In this way, an abnormality occurs in the input/output and the winding of the coil, causing an excessive current to flow, which causes the coil to overheat and when it exceeds the set value, the heat-sensitive element 3 begins to melt, and the heat-sensitive element 3 is parallel to the winding. The molten heat-sensitive element vibrates due to the alternating current flowing through the coil and the alternating magnetism, and the central part in the length direction gradually becomes thinner due to surface tension. The thinning center part splits into two, and the moment the spark sparks, it is completely cut off.

In this case, when the alternating current magnetism of the coil is weak or the magnetic direction is random, in the conventional overheating preventer, the rough magnetic flux directly acts on the heat-sensitive element whose top and bottom are held together with adhesive tape. In the present invention, since the magnetic piece 5 is attached to the recess 4 formed near the heat-sensitive element 3, both poles are generated in the magnetic piece 5 due to magnetic induction by the magnetic field of the wire ring, and this magnetic piece 5 spreads the magnetic flux. It has a suction effect.

Therefore, even if the magnetism of the wire is weak and the magnetic flux distribution is rough, the magnetic flux will be concentrated and dense at the magnetic piece 5 as shown in Figures 8 and 9, and a strong magnetic flux will be generated from the end face of the magnetic piece 5. and acts on the heat sensitive element 3.

Therefore, even when the generated magnetism is weak, it is possible to apply a strong and efficient magnetism to the heat-sensitive element 3, and even when the insulation coating 7 is closely surrounding the surrounding element and is strongly pressurized by the winding 9 from around it. Regardless, there is a preferable free space (vibration space) called the recess 6 on the outer periphery of the heat-sensitive element 3.

This synergizes with the magnetic force enhancement effect of the magnetic piece 5 described above to ensure a strong vibration effect, making it possible to accurately and reliably interrupt the circuit at the set temperature in any winding configuration of the coil. be.

Moreover, the heat-sensitive element 3 is eventually cut off by the spark,
At this time, the recess 6 also functions as a scattering space for the heat-sensitive elements 3, that is, the scattered heat-sensitive elements 3a naturally gather at the lower side of the recess 6' as shown in FIG. 10 due to gravity.

At this time, the magnetic piece 5 is fitted into the recess 4 and kept at a constant distance from the recess 6.

Therefore, there is no phenomenon in which the scattered heat-sensitive element group 3a is again welded in a line between the lead wires 2, 2, or in a line with the magnetic piece 5, and the degree of electrical insulation is very good. It is something that can be done.

As described above, according to the present invention, the recess 6 is provided in the base piece 1 around the heat-sensitive element 3 to provide a free space for vibration, and the magnetic piece 5 attached near the heat-sensitive element 3 focuses the magnetism. Therefore, even if the magnetic direction of the coil is random or the magnetism is weak, the vibration torque of the heat-sensitive element 3 can be made strong and reliable due to their synergistic effect. ,
This has the effect of being able to shut off the circuit very accurately and reliably at the set temperature.

In addition, by attaching the magnetic piece 5 to the recess 4 of the base piece 1, the magnetic piece 5 can be securely positioned and fixed.
There is no variation in magnetic strength for each product, and the electrical insulation is also good due to the above-mentioned fixing effect and the accommodation effect of the scattered heat-sensitive element by the recess 6 formed in the base piece 1 directly below the heat-sensitive element 3. Since this variation is eliminated, a highly reliable overheating preventer with uniform performance can be obtained.

In addition, the overall structure is simple, and in particular, the magnetic piece 5 can be easily attached to the recess 4, so that it can be manufactured at low cost.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway plan view showing an embodiment of the coil overheating preventer according to the present invention, Fig. 2 is a sectional view taken along line II-II in Fig. 1, and Fig. 3 is a cross-sectional view taken along line II-II in Fig. 1. FIG. 4 is a sectional view taken along the line IV--IV in FIG. 5 is a sectional view taken along the line VI-VI, FIG. FIG. 10 is an explanatory diagram showing the state of distribution, and FIG. 10 is an explanatory diagram showing the state of the heat-sensitive element in the present invention when it is fused. In the drawings, 1 is a base piece, 2 and 2 are lead wires, 3 is a heat-sensitive element, 4 is a recess, 5 is a magnetic piece, 6 is a four part, and 7 is an insulating coating.

Claims (1)

[Scope of utility model registration request] A plurality of substantially parallel lead wires 2, 2 are attached to a base piece 1 made of an electrically insulating material, and a heat-sensitive element 3 made of an easily meltable alloy is bridged and joined between the tips of the lead wires 2, 2. The base piece 1 has a lead wire 2 near the heat-sensitive element 3.
, a recess 4 is formed between the recess 4, a magnetic piece 5 is mounted in the recess 4, and the base piece 1 accommodates at least a longitudinally intermediate portion of the heat-sensitive element 3 directly below the heat-sensitive element 3. A heating preventer for wire wheels, characterized in that a recess 6 into which the wire can be inserted is formed, and an electrical insulation coating 7 is provided around a base piece 1 including the heat-sensitive element 3 and the magnetic piece 5.