JP2832968B2 - Heat detection device at the junction of electrical conductors - Google Patents

Description

The present invention relates to a device for detecting heat generation at a connection portion of an electric conductor, which detects abnormal heat generation at a connection portion of an electric conductor, for example, a linear connection portion or a branch portion.

B. Summary of the Invention The present invention relates to a heat generation detecting device for detecting heat generation at a connection portion of an electric conductor, comprising: a heat sensor body made of a shape memory alloy that returns to a shape due to a heat load generated at the connection portion of the electric conductor; The connection part with the tie wrap that attaches the sensor body to the connection part of the electric conductor,
By forming by joining by spot welding, it is possible to provide a highly reliable heat generation detecting device which detects abnormal heat generation at the connection portion of the electric conductor visually.

C. Prior Art In general, a connection part of an electric conductor, for example, a connection part of a feeder line (a straight connection part, a branch connection part, etc.) in a train line of an electric railway is shown in FIG. As shown in FIG. 4 and after inserting a feeder wire 1 made of hard copper stranded wire or hard aluminum stranded wire from both ends of the straight connecting pipe 2, the straight wire is connected using a wire connecting hydraulic machine (not shown). The connection pipe 2 is configured to be connected by being compressed and deformed.

However, in the connection portion of the electric wire 1 thus configured, a connection failure occurs in the following cases. (A) a hard copper stranded wire or a hard aluminum stranded wire to be connected is an old wire having a large amount of an oxide film adhered to the surface thereof, and the film is not sufficiently removed at the time of connection; When the stranded wire and the hard aluminum stranded wire are connected, (c) When the straight connecting tube 2 having a larger inner diameter than the specified outer diameter of the feeder wire 1 is used by mistake, (d) When the straight connecting tube 2 is This is the case where a compression die that does not fit the outer diameter is attached to a hydraulic machine and compressed.

In addition, since the connection work is often performed at midnight, the above-mentioned error is more likely to occur.

When the above connection failure occurs, especially when the connection is caused by compression deformation, the electrical contact between the inner surface of the straight connection pipe 2 and the outer surface of the electric wire 1 becomes incomplete and causes abnormal heat generation. And the connection in that state promotes air oxidation by heating, further deteriorating electrical contact,
Heat generation is further caused, and the influence of heat also promotes a decrease in material strength due to coarsening of crystal grains of the metal structure of the feeder wire 1, which may cause a disconnection accident.

In addition, in the case of this connection failure, the connection portion generates abnormal heat immediately after the connection, and becomes higher and hotter with the lapse of time. There is a risk of causing an accident.

For this reason, in order to prevent an accidental disconnection of the heat of the feeder wire 1 due to the poor connection, a thermo label discoloring at, for example, 60 ° C. is applied to an appropriate place on the outer surface of the straight connection pipe 2 or a thermo paint is applied. Alternatively, the surface temperature of the straight connection pipe 2 is measured by a non-contact infrared radiation thermometer,
Measures have been taken to detect abnormal heat generation and take early action.

D. Problems to be Solved by the Invention However, thermolabels and thermopaints do not have weather resistance and adhere to dust in the air, making it difficult to judge discoloration. Is more difficult to determine from the ground.

On the other hand, even in the infrared radiation thermometer, it is difficult to detect the abnormal heat generation of the connection pipe 2 at an early stage unless the target is small and the distance between the two is more than tens of meters, so that the connection pipe 2 does not generate heat. There was a problem.

Such a problem is a problem that occurs not only in the linear connection portion but also in the branch connection portion. In short, it is a problem that occurs in any portion of the connection portion.

The present invention has been made in view of the above points, and has made it possible to easily find a heat generation state at a connection portion of an electric conductor visually.
It is another object of the present invention to provide a new heat generation detecting device for a connection portion of an electric conductor, which is more reliable and easy to mount, and can be installed at an existing electric conductor connection portion.

E. Means for Solving the Problems The present invention provides a heat generation detecting device provided on a connection pipe or an electric conductor at a connection portion of an electric conductor, by using a heat storage material made of a shape memory alloy whose both ends return to a shape and change due to heat generation at the connection portion. It is characterized in that the joint between the sensor body and the tie wrap for attaching the sensor body to the connecting part is fixed by spot welding.

F. Function With the above-described configuration, when abnormal heat generation occurs at the connection portion of the electric conductor on which the heat detection device is installed, the heat sensor body is restored by the shape return accompanying the transformation to the parent phase. Both ends return to the shape and stand up so as to be separated from the surface of the connection pipe portion, and the rising state can be easily confirmed visually to detect the heat generation state.

In addition, there is an effect that the heat sensor body and the tie wrap can be easily and quickly connected.

G. Embodiment Hereinafter, an apparatus for detecting heat generation at a connection portion of an electric conductor according to the present invention will be described with reference to an embodiment shown in FIGS.

Note that, in FIGS. 1 and 2, the third
Parts corresponding to those in FIG. 4 and FIG.

FIG. 1 is a front view showing a connection part of a feeder wire, which is one of the electric conductors, to which the heat generation detecting device of the present example is mounted. Reference numeral 1 denotes a feeder wire, and reference numeral 2 denotes a straight connection pipe.

In the present example, detectors 6, 6 having different transformation temperatures are mounted at two locations near the center of the straight connection pipe 2.

The heat generation detecting device 6 is configured as shown in FIG. 2, and includes a fixed body such as a stainless steel tie wrap 7, a sensor fixing tool 8, and a long plate-shaped or rod-shaped heat sensor body 9.

The stainless tie wrap 7 constituting the fixed body is equivalent to a commonly used one, and the strap 10 is a non-magnetic stainless steel plate material having a thickness of 0.7 mm to 0.12 mm. It is of a self-locking type having a small and simple engagement structure.

In addition, the thermal sensor body 9 is a Ni- element that returns its shape along with the transformation of the deformed twin martensite into the parent austenite by the thermoelastic martensite transformation at a constant temperature.
It is a Ti-based shape memory alloy and is elongated.

Further, since the temperature of the connecting portion of the feeder wire is known to be about 60 ° C. or less in a normal state in summer, the heat sensor body 9 operates at 70 ° C. or more, And a plurality of types (for example, 70 ° C., 9
(0 ° C, 110 ° C) should be prepared and used in combination with different operating temperatures.

In addition, as for the part 13 for storing the shape in the shape memory alloy which is an element of the heat sensor body 9, the central part in the longitudinal direction of the long shape is a fixing part to the stainless steel tie wrap 7 and is slightly separated from the fixing part. It is preferable to set the two portions 13 on both sides (outside) from the viewpoint of easy deformation at the time of shape return. As shown in FIG. 1, when the temperature reaches or exceeds a predetermined temperature, both ends in the longitudinal direction of the heat sensor body 9 are deformed from the storage portion 13 outwardly (in a direction away from the connecting portion) by about 90 °, and heat A memory shape is applied so that the entire shape of the sensor body 9 is deformed into a U-shape.

The heat sensor body 9 configured as described above forms a heat generation detecting device by welding a central portion (middle of two storage portions 13) to a middle portion of the metal band 10 by spot welding 14.

That is, spot welding 14 is performed with the middle part of the metal band 10 intersecting between the two storage parts 13 of the heat sensor body 9. In particular, at the time of this spot welding, the heat sensor body 9 is
In this example, in a state where the entire shape is returned to a U-shape,
The spot welding 14 is carried out in a state where the metal band 10 is overlapped on the inner bottom side of the U-shape so as to cross. This is because if the spot welding 14 is performed after the shape of the heat sensor body 9 is restored, the welding position can be easily positioned, and the heat sensor body 9 can be colored or stamped for distinguishing front and back. This is because even if the mark is not provided, the side surface to which the metal band 10 is welded in the direction of shape return can be prevented from being erroneous.

For example, erroneous spot welding 14 causes the following problem.

First, when the position of the spot weld 14 is too close to the shape memory portion 13, the shape heat of the alloy is blurred by the welding heat at that time, and the alloy cannot completely return to the original shape.

Second, if the spot welding position overlaps the shape memory portion 13, the spot welding 14 will be peeled off due to the recovery force when the alloy returns to the shape.

Third, if the side of the heat sensor body 9 to be welded is mistaken, the following problem occurs. For example, when the metal band 10 is welded to the back of the normal, the outer surface of the convex portion when the heat sensor body 9 returns to its original shape, the heat sensor body 9 is attached to the connection portion when the heat generation detecting device is mounted. To the connection part, and
Is mounted so as to be wound and supported from the outside. Therefore, when abnormal heat generation occurs, the force for returning the shape to bend inside the heat sensor body 9 is suppressed by being pressed against the connection portion, and the original function cannot be exhibited.

Therefore, it is effective to spot-weld the metal band 10 to the heat sensor body 9 whose shape has been restored in advance. In addition,
Since the spot welding 14 is provided at one place and the band 10 is also a thin plate, it can be spot-welded in a short time, and the shape heat of the alloy is not blurred by welding heat at this time.

Although not shown, it is preferable to apply a fluorescent paint to the surface of the heat sensor body 9 in order to easily monitor the shape recovery of the shape memory alloy of the heat detection device configured as described above from a distance. Furthermore, if the transformation temperature specification of the detector is clarified by color coding 70 ° C transformation white, 90 ° C yellow, 110 ° C red, etc., the transformation temperature specification can be easily identified. It's convenient and doesn't make a mistake.

Then, the abnormal heat detection configured as described above, or
When using heat sensors with different operating temperatures, the heat generation state is color-coded, for example, 70 ° C for white standing, 90 ° C for yellow, 110 ° C for red. Can be easily detected.

Alternatively, means for changing the standing length depending on the temperature may be provided.

The heat detecting device 6 configured as described above connects the stainless tie wrap 7 with a straight connection pipe or a feeder branch pipe.
Alternatively, it is wound around a predetermined position of the feeder wire 1 in the vicinity thereof, and is fastened and attached by the buckle portion 12 in a tight state.

Further, the heat sensor body 9 is designed so that the surface of the iron sensor body 9 directly adheres to the surface of the straight connection pipe or the feeder branch pipe, or the vicinity of the feeder wire at a normal temperature without a fixing bracket or the like. Set to. By doing so, the abnormal heat generation at the connection portion is directly transmitted to the thermal sensor body 9 and the sensitivity can be improved.

The heat detecting device 6 of the present embodiment shown in FIG. 2 has one heat sensor body 9 of one kind of transformation temperature attached to a stainless steel band 10 and two parts near the center on the straight connecting pipe. A plurality of different detecting devices 6 are attached to each stainless steel band 10 at 70 ° C (white mark), 90 ° C.
The heat sensor bodies 9 at 110 ° C. (marked in red) and 110 ° C. (marked in red) may be mounted together at a slight distance. By doing so, installation work can be omitted and the detection device can be made more economical.

Further, as in this example, the heat generation detecting device 6 attached with the stainless tie wrap 7 is used not only during the work of renewing the connection of the feeder wire 1 but also after the work of connecting the feeder wire 1 or at the existing connection part in operation. 2. It can be easily tightened and mounted on the feeder branch pipe or the feeder 1 in the vicinity thereof.

Next, the operation of the detection device will be described with reference to FIG. 1. First, when there is no abnormality in the connection portion, the heat sensor body 9 made of a shape memory alloy is connected to the straight connection pipe 2, the feeder branch pipe, or the feeder. 1 is tightly adhered to the surface of the stainless steel tie 7 by the tightening force of the stainless tie wrap 7, but generates abnormal heat and causes the straight connection pipe 2 or the feeder branch pipe or the feeder 1 in the vicinity thereof.
Is higher than a predetermined temperature (for example, about 70 ° C.), the thermal sensor bodies 9 having the respective transformation temperature specifications return to the shape due to the transformation to the parent phase. Then, the heat sensor body 9 rises so as to be away from the surface of the straight connection pipe 2 or the feeder branch pipe or the feeder wire 1, and the entire shape of the heat sensor body 9 is deformed into a U-shape. That is, the memory shape in the parent phase of the shape memory alloy is the shape indicated by the dotted line. Such a shape restoration can be easily, instantly and surely visually confirmed by monitoring the light emission of the fluorescent paint applied to the surface of the thermal sensor body 9.

H. Effects of the Invention As described in detail above, according to the heat generation detecting device of the connection part of the electric conductor of the present invention, the heat sensor body formed of the shape memory alloy is connected to the tie wrap attached to the connection part of the electric conductor. Are joined by spot welding so that the following effects can be obtained.

Since the shape recovery of the shape memory alloy is used as the heat sensor body, it is possible to visually and instantaneously and surely determine and detect abnormal heat generation of the connection portion.

The joining operation between the heat sensor body and the tie wrap can be performed by a simple and quick operation by spot welding, and there is an effect that an inexpensive product can be provided because a fixture or the like is not required.

Since the heat sensor body joined to the tie wrap by spot welding is installed directly in contact with the surface of the connection part of the electric conductor without going through a fixture or the like, it has good heat conductivity,
This has the effect of enabling sensitive sensing.

[Brief description of the drawings]

FIG. 1 is a side view showing an embodiment of the apparatus for detecting abnormal heat generation of a connection portion of an electric conductor according to the present invention, FIG. 2 is a front view showing the apparatus for detecting abnormal heat generation, and FIG. FIG. 4 is a side view showing the electric wire connection portion, and FIG. 4 is a front view thereof. DESCRIPTION OF SYMBOLS 1 ... Feeding wire, 2 ... Straight connection pipe, 6 ... Abnormal heating detection device, 9 ... Heat sensor body, 10 ... Band, 11 ... Engagement hole,
12… buckle part, 13… shape memory part, 14… spot welding part.

──────────────────────────────────────────────────の Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H01R 4/00 H01R 4/70 H01R 43/00 B60M 1/12 G01N 25/72 G01R 31/00 G01K 11 / 00

Claims (1)

(57) [Claims] 1. A spot connecting a heat sensor body which returns to a shape due to a heat load generated at a connection part of an electric conductor and a tie wrap to be attached to the connection part of the electric conductor by spot welding. An apparatus for detecting heat generation at a connection portion of an electric conductor, wherein the device is configured.