JPH041966B2 - - Google Patents

Description

[Detailed Description of the Invention] Purpose of the Invention Industrial Application Field The present invention relates to a flexible protection structure configured to protect members to be protected, such as electric wires or conductors, while having flexibility. Concerning improvement of body structure.

2. Description of the Related Art For example, electric wires and the like are often deformed by being bent or bent depending on the location where they are installed. In addition, a coating is usually applied to prevent contamination or water intrusion from the outside and to provide shielding. However, as described above, since the covering is often deformed, the covering is required to protect the protected member while having flexibility.

FIG. 4 is a partially cutaway side sectional view showing an example of a conventionally used flexible protection structure. Here, a metal corrugated pipe 2 as a flexible protector is inserted over a wire 1 as an object to be protected. As is clear from the illustrated shape, the metal corrugated tube 2 has corrugations and therefore protects the wire 1 while providing flexibility.

However, since the metal corrugated pipe 2 of the flexible protective structure shown in FIG. 4 is made of a relatively rigid material with corrugations formed therein,
It does not inherently have much flexibility,
Therefore, it was not always possible to follow the deformation of the wire rod 1 smoothly. Furthermore, if an attempt was made to increase the amount of deformation, it would be necessary to deepen the peaks and valleys of the corrugation or to create a composite structure, which resulted in the disadvantage that the diameter would become larger than necessary. Further, even if a large deformable amount is obtained, the metal corrugated pipe 2 will be deformed in the same way even if the wire 1 is deformed beyond the permissible deformation limit. Therefore, the wire rod 1, which is a member to be protected, may be broken, and there is also the drawback that it is difficult to reliably protect the member to be protected.

FIG. 5 is a partially cutaway perspective view for explaining another example of a conventional flexible protection structure. Here, a rubber 4, a metal braid 5, and a resin coating 3 are applied around a conductor 3 as a member to be protected, and the metal braid 5 and resin coating 6 function as a protector. In this case, there were various drawbacks mentioned above.

Problems to be Solved by the Invention Therefore, an object of the present invention is to eliminate all of the above-mentioned drawbacks, to be able to smoothly follow the deformation of the member to be protected, and to be able to prevent deformation beyond the allowable deformation limit. An object of the present invention is to provide a flexible protective structure that can reliably prevent accidents such as wire breakage caused by

Means for Solving the Constituent Problems of the Invention The present invention has been made in order to solve the above-mentioned drawbacks, and at least a part of the protective body is
It is composed of an alloy that undergoes stress-induced martensitic transformation when deformed in the operating temperature range, and returns to its original phase when external force is removed, resulting in thermoelastic martensitic transformation that exhibits superelastic behavior. A flexible protective structure characterized by:

Since "at least a part" means "at least a part", the whole may be made of an alloy that causes such thermoelastic martensitic transformation, or only a part may be made of the alloy.

In addition, examples of "alloys that exhibit thermoelastic martensitic transformation that exhibit superelastic behavior" include Ni.
-Ti alloy, Cu-Al-Ni alloy, Cu-Al-Zn
Various known alloys can be used, such as alloys such as alloys.

“Exhibiting superelastic behavior in the operating temperature range” means
In other words, it means that the reverse transformation temperature is lower than the operating temperature range. Therefore, it is sufficient to use an alloy that exhibits such characteristics and undergoes thermoelastic martensitic transformation.

Note that the shape of the protector in the flexible protection structure of the present invention is not particularly limited, but
For example, as shown in the embodiments described later, it can be configured in various shapes such as a tape shape or a line shape.

Function As described above, this invention utilizes superelastic behavior in the protector portion, and therefore can deform much more flexibly than those that utilize normal elastic deformation, and protects the protector. It is possible to quickly and smoothly follow the deformation of the target member. This will be explained with reference to the stress-strain characteristic curve in FIG. In FIG. 3, the curve is the stress-strain characteristic curve of the alloy that causes thermoelastic martensitic transformation used in the present invention. Here, a curve for a Ni-44.8% by weight Ti alloy wire is shown. As is clear from this curve, in the alloy wire used in this invention, O→A→
Draw a stress-strain curve that changes from B to C.
Therefore, it can be seen that until the deformation exceeds point A and reaches point B, the stress does not increase much and the material can be deformed flexibly. In addition, if the stress is removed after deforming to point B, approximately B→A
→Distortion is removed by drawing a curve close to O. This behavior is called superelastic behavior.

On the other hand, the curve shown in FIG. 3 is a pressure-strain characteristic curve of a wire made of stainless steel.
As is clear from the curve, stainless steel has an extremely high Young's modulus and is therefore quite hard, and if it is deformed beyond point D, which is a small amount of strain, it will not return to point O even if the load is unloaded. You can see that it will be permanently deformed.

Furthermore, the stress-strain characteristic curve for a soft aluminum alloy wire with a low Young's modulus is shown in FIG. As is clear from this curve, when the soft aluminum alloy wire is subjected to a strain exceeding point F, which is a smaller amount of strain, it becomes permanently deformed and cannot return to its original state.

As is clear from the comparison of the stress-strain characteristic curves above, this invention utilizes superelastic behavior, so it can be deformed extremely flexibly compared to normal elastic deformation. It can also be seen that the range in which the wire returns to point O when the load is unloaded is extremely wide compared to the soft aluminum alloy wire.

Furthermore, as is clear from the response-strain characteristic curve of the alloy wire constituting the protector of the present invention, beyond the critical strain amount that can exhibit superelastic behavior, that is, point B, it enters the normal elastic deformation region and deforms considerably. Therefore, the protector of the present invention is constructed so that the amount of strain of the alloy when a stress that causes a deformation limit strain is applied to the member to be protected is smaller than this point B. By doing so, it is possible to reliably protect the member to be protected. In other words, by the time the member to be protected reaches its deformation tolerance limit, the protector will be distorted beyond the region where it exhibits superelastic behavior, making it considerably difficult to deform, which will ensure that accidents such as disconnection of the member to be protected will occur. Prevented.

DESCRIPTION OF THE EMBODIMENTS FIG. 1 is a schematic side view showing a first embodiment of the invention. In the protective structure of this example,
A protective body consisting of rubber 12, a Ni-44.8 wt% Ti tape 13 made of an alloy exhibiting superelastic behavior, and a resin coating 14 is attached around the Cu stranded wire 11 as a member to be protected. . Here, a Ni-44.8% by weight Ti alloy is used as an alloy exhibiting superelastic behavior, and is wound around the rubber 12 in the form of a tape. This Ni
Since the -44.8 wt% Ti alloy has a reverse transformation temperature of 5°C, it can be seen that it exhibits superelastic behavior at temperatures higher than this.

The electric wire with the structure shown in Figure 1 is
When used in electrical wires for conductors and leaders, even when bending force was applied, the N-44.8wt% Ti tape 13 was strained to approximately 5%.
It was confirmed that the tape 13 became hard and became difficult to bend any further. Therefore, it can be seen that it cannot be bent excessively, that excessive bending is not applied to the central Cu strand 11, and that low cycle fatigue fracture is unlikely to occur. It was also confirmed that the material deformed extremely flexibly within the range exhibiting superelastic behavior, and therefore the workability was extremely good.

For comparison, when conventional electric wires were used under the same conditions, the central Cu strands tended to bend, resulting in frequent breakage accidents.

FIG. 2 is a partially cutaway side view showing a second embodiment of the invention. The protective structure of this example includes a polyvinyl chloride resin layer 15 around the central Cu strand, Cu-14 weight% Al-3.8 as an alloy member.
A weight% Ni alloy wire 16 and a resin coating layer 17 are formed. Since the Cu-14 wt% Al-3.8 wt% Ni alloy wire has a reverse transformation temperature of -10°C, it can be seen that it exhibits superelastic behavior at temperatures higher than this temperature.

The electric wire shown in FIG. 2 is used to connect to a microphone, but in this case, the alloy wire 16 is terminal-attached so as to have a shielding effect, and the same wire as in the embodiment shown in FIG. 1 is used. When the flexibility and workability were tested, it was confirmed that it could be flexibly deformed due to superelastic behavior, and that breakage of the Cu stranded wire 11 inside could be reliably prevented.

Effects of the Invention As described above, according to the present invention, at least a portion of the protector undergoes stress-induced martensitic transformation and deforms when deformed in the service temperature range, and returns to its original phase when the external force is removed. Because it is composed of an alloy that undergoes thermoelastic martensitic transformation that exhibits superelastic behavior when it returns, it utilizes superelastic behavior, so it can be deformed flexibly and is therefore protected. It becomes possible to provide a flexible protection structure including a protection body that can smoothly and quickly follow the deformation of the target member. Further, the flexibility is provided by superelasticity, and therefore there is no need to form corrugations, so miniaturization can also be achieved. Furthermore, when the load is unloaded, the deformed object tries to return to its original state, so it is easy to work with, and if it is deformed beyond the region where it exhibits superelastic behavior, it becomes difficult to deform, so it is protected. It is possible to reliably prevent deformation beyond the permissible limit from being applied to the target member,
Therefore, accidents such as disconnection of members to be protected can be reliably prevented.

It should be pointed out that the present invention can be applied not only to electric wire cables but also to flexible protection structures in general that are configured to protect elongated wires while providing flexibility.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway side view showing a first embodiment of the invention. Figure 2 shows the second embodiment of this invention.
FIG. 2 is a partially cutaway side view for explaining an embodiment of the present invention. FIG. 3 is a diagram showing the stress-strain characteristics of the alloy wire used in the present invention. FIG. 5 is a partially cutaway sectional view for explaining an example of a conventional flexible protection structure. FIG. 4 is a perspective view for explaining another example of a conventional flexible protection structure. In the figure, 11 is a Cu stranded wire as a member to be protected, 13 is a Ni-44.8wt% Ti alloy tape as an alloy member, and 16 is a Cu alloy member.
-14wt%Al-3.8wt%Ni alloy wire is shown.

Claims (1)

[Scope of Claims] 1. A flexible protection structure comprising a member to be protected and a protector that protects the member to be protected while having flexibility, comprising: at least one of the protectors. The alloy is partially deformed by stress-induced martensitic transformation when deformed in the service temperature range, and returns to its original phase when external force is removed, resulting in thermoelastic martensitic transformation that exhibits superelastic behavior. A flexible protective structure comprising: 2. The critical strain at which the alloy exhibiting the thermoelastic martensitic transformation can exhibit superelastic behavior is the thermoelastic martensitic transformation when a stress that generates a strain within the permissible deformation limit is applied to the member to be protected. A flexible protective structure according to claim 1, wherein the amount of strain is greater than the amount of strain in the alloy that exhibits transformation. 3. The flexible protection structure according to claim 1 or 2, wherein the member to be protected is an electric wire.