JPH0520180B2 - - Google Patents

Description

[Detailed description of the invention]

<Industrial Application Field> The present invention relates to a circular compression stranded wire which is formed by sequentially twisting each layer in the same direction and then compression molding each layer. <Prior art and its problems> Conventional circular compression stranded wires have the following configurations. (a) Each layer is twisted in opposite directions alternately, such as right-handed and left-handed. With this configuration, the strands of the inner and outer layers are in cross-contact, so when compression molding is performed, the deformation of the contact area is larger than that of other areas, resulting in poor mechanical properties and flexibility. be. (b) All layers are twisted in the same direction, either right-handed or left-handed, and in this case, the diameter of the outer layer wires is smaller than that of the inner layer wires, or any n layer after the first layer is twisted. The number of strands in the wire is not as regular as 6n (n is an integer) like uncompressed circular layer stranded wire, but is made easier to compression mold by, for example, 5n+1. With this configuration, it is complicated to manage the wire diameter and the number of wires during the production of stranded wires, and furthermore, the outer layer wires may fall into the gaps between the inner layer wires, resulting in poor appearance. The present invention was made in view of the above-mentioned problems, and it is an object of the present invention to provide a circular compressed stranded wire having a smooth surface and excellent mechanical properties and flexibility. <Means for Solving the Problems> As a result of intensive research to achieve the above object, the present invention has found that by selecting the outer diameter and twisting pitch of each layer, wires with approximately equal diameters can be arranged in a normal configuration in each layer. central layer, first layer, second layer, ..., n-1th layer,
The number of strands in the nth layer (outermost layer) is 1, 6, 12, ..., 6
(n-1), 6n, and even when twisted in the same direction, it was found that the outer layer strands do not fall into the gap between the inner layer strands because the twist pitch multiples of the adjacent inner and outer layers are different. That is, as shown in Fig. 1, Dn, Dn _-1 ; Outer diameter of the nth layer and n-1st layer dn, dn _-1 ; Wire diameter of the nth layer and n-1st layer Pn, Pn _-1 ; When the pitch of the nth layer and the n-1th layer is set, the core diameter of the nth layer is Dn-dn, the core diameter of the n-1st layer is Dn _-1 -dn _-1 , the nth The pitch multiple Φn for the core diameter of the layer is Φn=Pn/(Dn-dn) (1) The pitch multiple Φn _-1 for the core diameter of the n-1th layer
is Φn _-1 = Pn _-1 /Dn _-1 −dn _-1 ) (2). Then, the closer Φn and Φ _o-1 become to each other, the more likely the outer layer strands fall between the inner layer strands. To prevent this, the pitch multiples of the adjacent inner and outer layers can be set to be different from each other, but in this case, if the pitch multiple of the inner layer is set smaller than the pitch multiple of the outer layer, long strands of wire will be required. Therefore, it is uneconomical. Therefore,
It is preferable to set the pitch multiple of the inner layer to be larger than the pitch multiple of the outer layer. Therefore, we considered how large the pitch multiple should be set, and found that it is sufficient to satisfy the condition Φn _-1 /Φn≧1.03 (3), as shown in Appendix 1 below.
This became clear from the results of 2. Note that from the viewpoint of preventing the outer layer strands from falling between the inner layer strands, it is not necessary to set an upper limit on the pitch multiple ratio Φn _-1 /Φn of the adjacent inner and outer layers.
In order to maintain good flexibility, as described later,
The pitch of the inner and outer layers is Pn _-1 ≦Pn, Pn _-2 ≦Pn _-1 ,...
It is preferable that Therefore, by substituting equations (1) and (2) into equation (3), we get
Pn _-1 /Pn≧1.03 ( _{Dn -1} −dn _-1 ) / (Dn − dn) (4). Also, if we set Dn _-1 /Dn = Kn, then dn = (Dn - Dn _-1 ) / 2 = Dn (1 - Kn) / 2dn _-1 = (Dn _-1 - Dn _-2 ) /
2 = (Dn _-1 −Dn _-1 Kn _-1 )/2 = Dn _-1 (1−Kn _-1 )/2, so by substituting these equations into equation (4), Pn _-1 /Pn ≧1.03(DnKn−DnKn(1−Kn _-1 )/
2)/(Dn-Dn(1-Kn)/2)≧1.03DnKn(1
-1/2+K _o-1 /2) Dn (1-1/2+Kn/2) ≧1.03Kn (1+Kn _-1 / (1+Kn) ∴Pn _-1 ≧1.03PnKn (1+Kn _-1 ) / (1+Kn) (5) Therefore, we first select the pitch Pn of the outer layer, and then
Select Pn _-1 so as to satisfy equation (5), and then
It is sufficient to select Pn _-2 , Pn _-3 ,... In addition, when the diameter of the original wire (hereinafter referred to as input wire) forming each layer is almost the same and the compression ratio of each layer is approximately the same, Kn=Dn _-1 /Dn=√ _-1 (6 ) Kn _-1 = Dn _-2 / Dn _-1 = √ _{-2 -1} (7) (Here, Nn, Nn _-1 , ...; nth layer, nth -
(number of each strand in one layer). The values of Kn, Kn _-1 , ... in this case are as shown in Table 1.

[Table] Generally, since Kn>Kn _-1 (8), in equation (5), (1+Kn _-1 )/(1+Kn)<1. Therefore, from equation (5), 1.03PnKn (1+Kn _-1 )/(1+Kn) <1.03PnKn Therefore, Pn _-1 >1.03PnKn (9), and the pitch of each layer is determined according to equation (9). If selected, it will be safer and easier to design. Now, if we set X=(1-Pn _-1 /Pn)/Kn, Pn _-1 /Pn=1-KnX (10) Substituting equation (10) into equation (9), 1-KnX＞1.03Kn ∴X<1/Kn−1.03 (11) That is, if formula (11) is satisfied, formula (9) is satisfied. Furthermore, in equation (10), if X=0, then Pn _-1 =Pn. It is not preferable that Pn _-1 > Pn. In other words, in order to maintain good flexibility, it is preferable that Pn _-1 ≦Pn, so 0<X<1/Kn−1.03 (12) For example, calculations can be made using the same value of X for each layer of a multilayer twisted wire. <Examples> Hereinafter, the present invention will be explained based on examples.
Each of the circular compressed strands shown in Attached Table 1 uses strands of approximately the same diameter, and the compression ratio of each layer is approximately equal, and the pitch of each layer is selected by determining the X value. In order to satisfy equation (3), it is sufficient to satisfy equation (11), and as is clear from Appendix 1, in order to satisfy equation (11), the outermost layer and the layer below it must be In this relationship, it is preferable that X be in the following range. For 500mm ² (61 strands), 0≦X≦0.254 For 120mm ² (37 strands), 0≦X≦0.364 For 50mm ² (19 strands), 0≦X≦0.617 The pitch is selected based on equation (5), therefore, equation (3), and Pa is Φn _-1 /Φn.
This is the case where Pb is set to 1.03, Pb is set to 1.02, and Pc is set to 1.01, and it can be seen that it is sufficient if Φn _-1 /Φn is 1.03 or more.

【table】

[Table] Symbols in the table ○: Good, △: Fairly poor.
×；Bad

[Table] Symbols in the table ○: Good, △: Fairly bad
Bad; Bad <Effects of the Invention> As is clear from the above examples, according to the present invention, a circular compression twisted twisted in the same direction which has a smooth appearance and excellent flexibility and mechanical properties can be obtained. A line is obtained. Further, there is no need for complicated wire management. Therefore, if the present invention is applied to a cross-linked polyethylene insulated power cable, extremely large effects such as no need for a separator tape to prevent the insulator from digging into the conductor gap can be obtained.

[Brief explanation of the drawing]

The drawing is a cross-sectional view of a circular compression strand showing an embodiment of the present invention. Dn, Dn _-1 , . . . are the outer diameters of the n-th layer, n-1 layer, . . . , and dn, dn _-1 , .

Claims (1)

[Claims] 1. Each layer is made by sequentially twisting strands of substantially equal diameter in the same direction, and then compression molding each layer to form a central layer, first layer, second layer, ..., n-1th layer. layer, the number of strands in the n-th layer (outermost layer) is 1, 6, 12, ..., 6 (n-
1), 6n circular compressed stranded wire, Dn, Dn _-1 , ...; nth layer, n-1th layer, ... outer diameter Pn, Pn _-1 , ...; nth layer, n-1th layer Twisting pitch of layer, Kn, Kn _-1 ,...; Dn _-1 /Dn, Dn _-2 /Dn _-1 ,...
(n is an integer), Pn _-1 /Pn≧1.03Kn (1+Kn _-1 )/(1+Kn),
Pn _-2 /Pn _-1 ≧1.03Kn _-1 (1+Kn _-2 )/(1+
Kn _-1 ),..., and the outer diameter and twist pitch of each layer are selected so that Pn _-1 ≦Pn, Pn _-2 ≦Pn _-1 , .... 2 The central layer, the first layer, the second layer, ..., the n-1th layer
layer, number of strands in nth layer (outermost layer), 1, 6, 12,
..., 6(n-1), 6n, N ₀ , N ₁ , N ₂ ,...Nn _-1 ,
Let Nn be the radial thickness dn of each layer after compression,
dn _-1 , ... are almost equal, and the ratio of the outer diameters of adjacent layers is Kn = √ _-1 , Kn _-1 = √ _-2
The circular compressed stranded wire according to claim 1, characterized in that Nn _-1 , . . . 3 Pn _-1 /Pn≧1.03Kn, _{Pn -2} /Pn _-1 ≧
The circular compressed stranded wire according to claim 1 or 2, characterized in that the outer diameter and twisting pitch of each layer are selected so that 1.03Kn _{-1 , .} . .