JPS6312301Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a metal flexible tube, such as an aluminum sheath for an aluminum sheathed cable.

Background and Purpose For example, when connecting aluminum sheathed cables with the same diameter, the cable sheath 10
0 and the corrugated connecting tube 200 are also necessarily required.

However, since conventional aluminum sheathing has a single closely spaced spiral wave, it is difficult to match the peaks and valleys when making connections.

This point will be explained in more detail as follows.

Cable sheath 10 as shown in "Figure 1B"
If 0 is cut along CC, for example, the cross section will be as shown in "Figure 1C". P is the center of the cable inside, and Q is the center of the cut circle.

However, if it is cut along the line DD, which is a little farther from C, the cross section will look like that shown in Figure 1D, and the center Q of the cut circle will move to a different location.

That is, the cross-sections of "Fig. 1C" and "Fig. 1D" do not match because the peaks and valleys do not match.

The conventional waveforms are close together as described above, and the angle α between the tube axis and the peaks (or valleys) is large. For this reason, even if the distance between C and D is not as far apart as mentioned above, for example, even if you cut it a little further away from C, the cross section will be different, making it difficult to cut at exactly the same cross section. It is.

This invention aims to solve this problem.

Embodiment (FIGS. 2 and 3) 10 is a metal pipe made of aluminum or the like. The tube wall is provided with a spiral groove 12 that continues in a diagonal direction with respect to the axial direction. Its width A (Fig. 3)
are equal over the entire length. Also, groove 12
In this method, at least two spirals are provided, one in the right-handed direction and the other in the left-handed direction, and these are made to intersect with each other.

A plurality of grooves 12 (four in FIG. 2) are provided side by side. At that time, the intervals between the grooves 12 are made equal.

Method for forming the groove 12: For example, the pipe 10 is fed through two dies 20 having a cross-sectional shape as shown in FIG. 4, and each die 20 is continuously rotated clockwise and counterclockwise.

Note that by changing the intersecting angle of the grooves 12, the degree of flexibility can be changed.

Effects of the invention (1) Since the width A of the groove is the same over the entire length, the cross-sectional shape of the tube is the same for each pitch (B in the case of Figure 2). Therefore, by cutting the tube at a point where the cross-sections are of the same shape, the seams can be easily matched. Furthermore, since the grooves 12 intersect with each other, by using the intersecting points (such as C and D in FIG. 2) as a guide, it is possible to easily find the cutting point of the same cross section.

(2) Since the grooves 12 are formed into a spiral shape that intersects with each other, it is flexible.

(3) When this flexible tube is used for the sheath of an OF cable, the oil passage will be shorter than one with a spiral groove when performing forced cooling.

(4) Since a plurality of helical grooves in both the right-handed and left-handed screw directions are provided side by side, the angle α between the groove and the tube axis (see Figure 1B) is smaller than before. Therefore, even if the cut edge is slightly misaligned, the cross section will not change significantly as in the conventional case. Therefore, the task of cutting at the same cross-sectional shape becomes easier.

[Brief explanation of the drawing]

FIG. 1A is an explanatory diagram of the prior art, and FIG. 1B is a partially enlarged view of the cable sheath 100, showing its C-C
and DD cross sections are shown in FIGS. 1C and 1D, respectively. FIG. 2 is an explanatory diagram schematically showing an embodiment of the present invention, FIG. 3 is a cross-sectional view taken at - in FIG. 2, and FIG. 4 is a cross-sectional view of a die used during manufacturing. 10...pipe, 12...groove.

Claims (1)

[Scope of utility model registration request] A flexible tube characterized in that a plurality of left-handed helical grooves and right-handed helical grooves of equal width are formed on the wall surface of the tube at equal intervals along the entire length.