Twisted wire and heater

Abstract

To provide a twisted wire having superior bending resistance, and a heater having the twisted wire.SOLUTION: A twisted wire 1 of the present invention comprises a plurality of Cu-Ag alloy element wires 10 twisted together. The plurality of Cu-Ag alloy element wires 10 each have a conductor diameter of 0.02 mm to 0.06 mm. Defining the outer diameter of the twisted wire 1 as X mm and the twist pitch of the twisted wire 1 as Y mm, Y / X is 16 or more.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a stranded wire and a heater having the stranded wire as a heating wire. [Background technology]

[0002] It is known that an electric heating wire (heater wire) that generates heat when electricity is passed through it is used in vehicle seat heaters, steering heaters, and the like. A stranded wire made of multiple thin wires twisted together is used as the electric heating wire. For example, Patent Document 1 discloses a stranded wire used as the electric heating wire. This stranded wire is made of multiple copper-silver alloy wires twisted together. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2004-55179 A Summary of the Invention [Problem to be solved by the invention]

[0004] The stranded wire is often used as a heating wire in places where repeated loads are applied, such as in seat heaters, as described above, and therefore is required to have bending resistance. An object of the present invention is to provide a stranded wire having good flex resistance, and a heater having the stranded wire. [Means for solving the problem]

[0005] In order to solve the above problem, according to one aspect of the present invention, A stranded wire in which a plurality of Cu-Ag alloy wires are stranded together, The conductor diameter of each of the plurality of Cu-Ag alloy wires is 0.02 mm to 0.06 mm; The present invention provides a stranded wire, characterized in that, when the outer diameter of the stranded wire is X mm and the strand pitch of the stranded wire is Y mm, Y / X is 16 or more.

[0006] According to another aspect of the present invention, There is provided a heater comprising the above-mentioned stranded wire as a heating wire. Effect of the Invention

[0007] According to the present invention, it is possible to provide a stranded wire having good bending resistance, and a heater including the stranded wire. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1A is a schematic side view showing the twist pitch of the stranded wire, and FIG. 1B is a schematic cross-sectional view showing the outer diameter of the stranded wire. [Diagram 2] 2A and 2B are diagrams showing the arrangement of two types of Cu—Ag alloy wires in a stranded wire. [Diagram 3] 3A and 3B are diagrams for explaining the bending resistance test. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, a stranded wire according to a preferred embodiment of the present invention will be described. In this specification, when a numerical range is indicated by "to", the lower limit and upper limit are included in the numerical range.

[0010] Fig. 1A is a schematic side view of a stranded wire according to one embodiment of the present invention, and Fig. 1B is a schematic cross-sectional view of the stranded wire 1. As shown in Figs. 1A and 1B, the stranded wire 1 has a structure in which a plurality of Cu-Ag alloy wires 10 are stranded together. Also, as shown in Fig. 1B, the Cu-Ag alloy wires 10 have an insulating coating 12 around a conductor 11. The stranded wire 1 is used as a heating wire, for example, by being included in a heater. Here, when the twist pitch of the twisted wire 1 is Y mm and the outer diameter is X mm, the twisted wire has good bending resistance when the ratio Y / X of the twist pitch to the outer diameter is 16 or more. The bending resistance will be described in detail later with reference to examples. The twist pitch is the axial length of one of the multiple strands (the strand marked with diagonal lines in FIG. 1A) twisted in a spiral shape as shown in FIG. 1A, when tracing this strand, as the strand makes one revolution (360° rotation) around the central axis of the stranded wire 1.

[0011] The stranded wire 1 may be composed of one type of Cu-Ag alloy wire 10 having the same Ag content in the conductor 11, or may include two or more types of Cu-Ag alloy wires 10 having different Ag contents in the conductors 11.

[0012] When the stranded wire 1 is composed of one type of Cu-Ag alloy wire 10, the composition of the conductor of the Cu-Ag alloy wire is not particularly limited, but may contain, for example, 3 to 10 mass % Ag, with the remainder being Cu and unavoidable impurities.

[0013] On the other hand, when the stranded wire 1 is composed of two or more types of Cu-Ag alloy wires, it is preferable that the stranded wire 1 includes a first Cu-Ag alloy wire having a conductor containing 1 to 5 mass% Ag, with the remainder being Cu and unavoidable impurities, and a second Cu-Ag alloy wire having a conductor containing 8 to 12 mass% Ag, with the remainder being Cu and unavoidable impurities.

[0014] In this way, when the stranded wire 1 includes two types of wires with different Ag contents in the conductor, i.e., the first Cu-Ag alloy wire 10a and the second Cu-Ag alloy wire 10b, the arrangement of the first Cu-Ag alloy wire 10a and the second Cu-Ag alloy wire 10b is not particularly limited and can be appropriately selected according to the required bending resistance, maximum test force, etc. For example, the arrangement of the first Cu-Ag alloy wire 10a and the second Cu-Ag alloy wire 10b may be arranged according to the required bending resistance and maximum test force, as shown in Figures 2A and 2B. For example, as shown in FIG. 2A, the first Cu—Ag alloy wire 10a may be disposed on the inside of the stranded wire 1, and the second Cu—Ag alloy wire 10b may be disposed on the outside of the stranded wire 1. Alternatively, as shown in FIG. 2B, the first Cu—Ag alloy wire 10a may be disposed on the outside of the stranded wire 1, and the second Cu—Ag alloy wire 10b may be disposed on the inside of the stranded wire 1.

[0015] The stranded wire may include three or more types of Cu-Ag alloy wires 10. For example, the stranded wire may include, in addition to the first Cu-Ag alloy wires 10a and the second Cu-Ag alloy wires 10b, other Cu-Ag alloy wires having different Ag contents.

[0016] It is preferable that the stranded wire 1 is configured to generate a predetermined amount of heat when a predetermined current is passed through it. For example, in the case of vehicle-mounted applications, the supply voltage is low, so it is preferable to set the current to less than 3 Ω / m.

[0017] The number of Cu—Ag alloy wires in the stranded wire 1 may be appropriately adjusted so as to obtain a desired amount of heat generation. The number of Cu—Ag alloy wires in the stranded wire 1 is not particularly limited, but is about 5 to 60, for example. As described above, when the stranded wire 1 has the first Cu-Ag alloy wires 10a and the second Cu-Ag alloy wires 10b, the ratio of the number of the first Cu-Ag alloy wires 10a and the number of the second Cu-Ag alloy wires 10b may be appropriately set according to the desired characteristics, such as bending resistance and maximum test force. For example, when the number of the first Cu-Ag alloy wires and the number of the second Cu-Ag alloy wires are almost the same, and the ratio of the number of the first Cu-Ag alloy wires / the number of the second Cu-Ag alloy wires is close to 1, the stranded wire 1 exhibits intermediate characteristics between the stranded wire 1 having only the first Cu-Ag alloy wires 10a and the stranded wire 1 having only the second Cu-Ag alloy wires 10b (Cu-Ag alloy wire with an intermediate Ag content between the two). The ratio of the two may be appropriately set according to the desired characteristics of the stranded wire 1. The ratio of the two may be, for example, 0.1 to 10, or 1.

[0018] 1B, the Cu—Ag alloy wire 10 has a conductor 11 and an insulating coating 12 therearound. The thickness of the insulating coating 12 is, for example, 0.001 to 0.01 mm. As shown in FIG. 1B, in this embodiment, the cross-sectional shape of the conductor 11 is circular, and the cross-sectional shape of the Cu—Ag alloy wire 10 is also circular. The conductor may be a Cu-Ag alloy wire as described above. In this embodiment, the insulating coating is an enamel coating. That is, in this embodiment, the Cu-Ag alloy wire is an enameled wire. The enamel coating may be formed by applying and baking a known varnish to the wire. Examples of the varnish include varnishes containing polyurethane, polyesterimide and polyamideimide, varnishes containing polyamideimide, varnishes containing polyimide, etc.

[0019] The conductor diameter of the Cu-Ag alloy wire may be 0.02 mm to 0.06 mm. If the conductor diameter of the Cu-Ag alloy wire is larger than 0.06 mm, the bending resistance of the stranded wire 1 is deteriorated. On the other hand, if the conductor diameter is smaller than 0.02 mm, the wire is easily broken during work, and workability is reduced. Details will be described later with reference to examples.

[0020] Specifically, the bending resistance and maximum test force of the stranded wire 1 may be as follows. In a 180° bending resistance test described later, the stranded wire 1 preferably has a 180° bending resistance of, for example, 1400 times or more, and more preferably has a 180° bending resistance of 3000 times or more. In a 90° bending resistance test described later, the stranded wire 1 preferably has a 90° bending resistance of, for example, 8000 times or more, and more preferably has a 90° bending resistance of 15000 times or more. The stranded wire 1 has a maximum test force of, for example, 20 N or more in a maximum test force test described later.

[0021] (effect) In the stranded wire according to the present embodiment, the conductor diameter of each of the multiple Cu-Ag alloy wires is 0.02 mm to 0.06 mm, and when the outer diameter of the stranded wire is X mm and the twist pitch of the stranded wire is Y mm, Y / X is 16 or more, and therefore the stranded wire has good bending resistance. EXAMPLES

[0022] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0023] Cu-Ag alloy wires 1 to 3 having different Ag contents and Cu-Ag alloy wire 4 having a different conductor diameter from Cu-Ag alloy wire 3 were manufactured. These wires were used to manufacture and evaluate stranded wires 1-1 to 1-3, 2-1, 3-1 to 3-3, 4-1 to 4-3, and 5-1 to 5-3. The manufacture of the wires will be described first, and then the manufacture and evaluation of the stranded wires will be described.

[0024] (Production of Cu-Ag alloy wire 1) A Cu-based alloy cast rod containing 10 mass% Ag with the remainder being Cu and unavoidable impurities and a wire cold-worked to the middle were subjected to heat treatment, and then cold-worked to 0.05 mm to produce Cu-Ag alloy wire 1. The obtained Cu—Ag alloy wire was coated with varnish and baked to enamel-coat the Cu—Ag alloy wire, thereby obtaining a Cu—Ag alloy wire 1.

[0025] (Manufacture of Cu-Ag alloy wires 2 to 4) Cu—Ag alloy wire 2 was produced in the same manner as Cu—Ag alloy wire 1, except that the raw materials were melted to prepare a melt (molten metal) containing 6 mass % Ag, with the remainder being Cu and unavoidable impurities. A Cu—Ag alloy wire 3 was produced in the same manner as the production of the Cu—Ag alloy wire 1, except that the raw materials were melted to prepare a melt (molten metal) containing 3 mass % Ag with the remainder being Cu and unavoidable impurities. A Cu—Ag alloy wire 4 was produced in the same manner as the Cu—Ag alloy wire 3, except that the wire was drawn to a diameter of 0.06 mm.

[0026] (Manufacture of stranded wires 1-1 to 4-4) As shown in Table 1, each strand was produced as follows. Fourteen Cu-Ag alloy wires 1 were twisted together at a twist pitch of Y mm and an outer diameter of X mm so that Y / X was 19.5, 16, and 14.5, respectively, to produce twisted wires 1-1, 1-2, and 1-3. Thirteen Cu-Ag alloy wires 2 were used and twisted together to produce a twisted wire 2-1, with a twist pitch of Y mm and an outer diameter of X mm, such that Y / X was 19.5. Twelve Cu-Ag alloy wires 3 were twisted together at a twist pitch of Y mm and an outer diameter of X mm so that Y / X was 19.5, 16, and 14.5 to produce twisted wires 3-1, 3-2, and 3-3, respectively. Six Cu-Ag alloy wires 1 and seven Cu-Ag alloy wires 3 were twisted together to produce twisted wires 4-1, 4-2, and 4-3, respectively, with a twist pitch of Y mm and an outer diameter of X mm, so that Y / X was 19.5, 16, and 14.5. Twelve Cu-Ag alloy wires 4 were twisted together to produce twisted wires 5-1, 5-2, and 5-3, respectively, with a twist pitch of Y mm and an outer diameter of X mm such that Y / X was 19.5, 16, and 14.5.

[0027] The number of wires in each of the above stranded wires was determined from the viewpoint of making the conductor resistance of each stranded wire approximately the same (approximately 0.9 Ω / m as shown in Table 1), as shown in Table 1. The twisting was performed using a twisting machine. The twisting pitch Y was calculated by stretching the wire over a specified length L, fixing one end and rotating the other end in the opposite direction to the twisting direction, and counting the number of rotations until the twisted wire was completely unraveled (twisting pitch Y = twisted wire length L ÷ number of rotations). The outer diameter X was calculated by direct measurement using a micrometer or video microscope, or by a formula (outer diameter = 1.155 × conductor diameter × √ number of twisted wires) based on the diameter of the Cu-Ag conductor and its number.

[0028] (Measurement and evaluation of stranded wires 1-1 to 5-3) The obtained stranded wire was subjected to the following measurements: conductor resistance, 180° bending resistance test, 90° bending resistance test, maximum test force measurement, and outer diameter measurement.

[0029] Conductor Resistance Using a potentiometer, the electrical resistance of five samples was measured in a room controlled at 20°C (±2°C), and the average conductor resistance (Ω / m) was calculated. The distance between the voltage terminals was 1000 mm. The calculation results are shown in Table 1.

[0030] <180° bending resistance test> The 180° bending resistance test was performed using a jig in which two plates were configured to be rotatable via a hinge, as shown in FIG. 3A. First, the two plates were opened so that the angle between them was 180°, and the stranded wire 1 was fixed on top of the two plates. Next, the two plates were brought closer together until the distance between them was twice the outer diameter of the stranded wire 1, and the stranded wire 1 was bent. Finally, the stranded wire 1 that had been opened so that the angle between the two plates was 180° was returned to its original state. This series of operations was counted as one cycle, and was repeated until one or more of the strands in the stranded wire 1 broke, and the number of cycles at which they broke was measured. The measurement results are shown in Table 1.

[0031] <90° bending resistance test> For the 90° bending resistance test, as shown in FIG. 3B, a weight 2 was hung from one end of the straightened stranded wire 1, and the stranded wire 1 was placed between two mandrels 3. The weight of the weight was 200 g. Next, the stranded wire 1 was bent 90° once to the left and once to the right. Finally, the stranded wire 1 was returned to its original position and straightened out. This series of operations was counted as one cycle and was repeated until one or more of the strands in the stranded wire 1 broke, and the number of cycles at which breakage occurred was counted. The measurement results are shown in Table 1.

[0032] <Maximum test force> In accordance with JIS Z 2241 (2022), the maximum test force was measured for each of five samples, and the average value (N) was calculated. The calculation results are shown in Table 1.

[0033] <Outer diameter> The outer diameter of the stranded wire was measured directly using a micrometer or video microscope, or calculated from the diameter of the Cu-Ag conductor and its number (outer diameter = 1.155 × conductor diameter × √number of strands). The measurement results are shown in Table 1.

[0034] [Table 1]

[0035] As can be seen from the comparison of stranded wires 1-1 to 1-3 in Table 1, the results of the 180° bending resistance test tend to improve as Y / X increases. This was also the case for stranded wires 3-1 to 3-3, 4-1 to 4-3, and 5-1 to 5-3. It is presumed that the reason why the 180° bending resistance improves as Y / X increases is that the strands are more likely to move in the longitudinal direction when the stranded wire is bent, and the bending point changes each time, increasing the number of times until the wire breaks. Note that this reason is merely a presumption and does not limit the present invention. Furthermore, as shown in Table 1, as Y / X increases, it becomes possible to increase the speed at which stranded wire is manufactured, thereby increasing productivity. From the viewpoint of bending resistance and productivity, the Y / X ratio of the stranded wire is preferably 16 or more. The upper limit of Y / X may be, for example, 30 from the viewpoint of ease of handling of the stranded wire. In other words, Y / X may be 30 or less.

[0036] As can be seen from a comparison of strands 3-1 to 3-3, which have a conductor diameter of 0.05 mm in Table 1, and strands 5-1 to 5-3, which have a conductor diameter of 0.06 mm, It was found that the smaller the value, the better the results of the 180° bending test. Also, the result of the 180° bending resistance test should be 1400 times or more. From these facts, the conductor diameter of the strand may be 0.02 mm to 0.06 mm. The reason why the 180° bending resistance improves as the conductor diameter of the strand becomes smaller is presumed to be because the smaller the conductor diameter, the smaller the effect of reducing the amount of bending strain applied to the strand. Note that this reason is merely presumed and does not limit the present invention.

[0037] Comparing stranded wires 1-1 to 1-3 in Table 1, which have 14 strands with an Ag content of 10% by mass, stranded wires 3-1 to 3-3, which have 12 strands with an Ag content of 3% by mass, and stranded wires 4-1 to 4-3, which have 6 strands with an Ag content of 10% by mass and 7 strands with an Ag content of 3% by mass, stranded wires 1-1 to 1-3 had better results in the 180° bending test than 3-1 to 3-3 and 4-1 to 4-3.

[0038] In addition, when comparing stranded wires 3-1 to 3-3 and 4-1 to 4-3, the results of the 180° bending resistance test were almost the same, but the results of the 90° bending resistance test were better for stranded wires 4-1 to 4-3. This is because in the 90° bending test, the bending resistance test is performed while applying a load as shown in Fig. 3B, so not only bending resistance but also tensile strength is evaluated, and as shown in Table 1, stranded wires 4-1 to 4-3 have higher tensile strength.

[0039] Comparing stranded wire 2-1, which has 13 strands with an Ag content of 6% by mass in Table 1, with stranded wire 4-1, which has 6 strands with an Ag content of 10% by mass and 7 strands with an Ag content of 3% by mass, the bending resistance and maximum test force were almost the same. This is thought to be because the average Ag content per strand in stranded wires 2-1 and 4-1 is almost the same.

[0040] From the above, a stranded wire having a conductor with a higher Ag content tends to have higher bending resistance and maximum test force. Also, if the Ag content of the stranded wire is approximately the same, the bending resistance and maximum test force will be approximately the same. Therefore, from the viewpoint of increasing bending resistance and maximum test force, it is better to increase the Ag content of the twisted wire. Since the mechanical properties improve as the Ag content increases, a wide range of requirements can be met by manufacturing strands with multiple silver concentrations. In addition, by combining and twisting strands with a high Ag concentration (e.g., Ag concentration 10% by mass) and strands with a low Ag concentration (e.g., Ag concentration 3% by mass), it is possible to obtain properties equivalent to those of a stranded wire twisted only with strands with an intermediate Ag concentration (e.g., Ag concentration 6% by mass). Therefore, from the viewpoint of balancing the bending resistance, the maximum test force, and the cost, it is preferable that the stranded wire contains two or more types of Cu-Ag alloy wires having conductors with different Ag contents.

[0041] More specifically, the multiple Cu-Ag alloy wires preferably include a first Cu-Ag alloy wire containing 3 mass% Ag and having a conductor with the remainder being Cu and unavoidable impurities, and a second Cu-Ag alloy wire containing 10 mass% Ag and having a conductor with the remainder being Cu and unavoidable impurities. [Industrial Applicability]

[0042] According to the present invention, for example, a heater can be provided that has a stranded wire having good bending resistance as a heating wire. [Explanation of symbols]

[0043] 1 stranded wire 2 Weight 3 Mandrel 10 Cu-Ag alloy wire 10a 1st Cu-Ag alloy wire 10b 2nd Cu-Ag alloy wire 11 Conductor 12 Insulation coating

Claims

1. A stranded wire in which a plurality of Cu—Ag alloy wires are stranded together, The conductor diameter of each of the plurality of Cu-Ag alloy wires is 0.02 mm to 0.06 mm; When the outer diameter of the stranded wire is X mm and the strand pitch of the stranded wire is Y mm, Y / X is 16 or more. twisted wire.

2. 2. The stranded wire according to claim 1, wherein the plurality of Cu-Ag alloy wires include two or more types of Cu-Ag alloy wires having conductors with different Ag contents.

3. 3. The stranded wire according to claim 2, wherein the plurality of Cu-Ag alloy wires include a first Cu-Ag alloy wire having a conductor containing 1 to 5 mass% Ag and the remainder being made of Cu and inevitable impurities, and a second Cu-Ag alloy wire having a conductor containing 8 to 12 mass% Ag and the remainder being made of Cu and inevitable impurities.

4. 4. The stranded wire according to claim 3, wherein the first Cu—Ag alloy strand is disposed on an inner side of the stranded wire, and the second Cu—Ag alloy strand is disposed on an outer side of the stranded wire.

5. 4. The stranded wire according to claim 3, wherein the first Cu—Ag alloy strand is disposed on an outer side of the stranded wire, and the second Cu—Ag alloy strand is disposed on an inner side of the stranded wire.

6. A heater comprising the stranded wire according to any one of claims 1 to 5 as a heating wire.

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