JPH0425644B2 - - Google Patents

Description

[Detailed description of the invention]

[Field of Application of the Invention] The present invention relates to a wire and a coil through which a high-frequency current flows. [Prior Art] Generally, when high-frequency current is passed through a conductor, there is a phenomenon in which the high-frequency current is localized to the surface layer of the conductor and does not enter the conductor. This is called the skin effect. The effect of increasing the effective resistance due to the high frequency current flowing only on the surface of the conductor becomes severe when the radius of the wire is equal to or greater than the skin depth δ. To avoid this, ribbon-shaped conducting wires are used or thin wires are insulated and twisted together so that the current is distributed uniformly across the cross section. The latter is the litz line (litz line).
wire). On the other hand, there is a magnetic bubble memory as a device that uses a coil through which a high-frequency current flows. That is, a magnetic bubble memory is provided with a rotating magnetic field generating circuit for transferring bubble domains, and a coil is used as a component of the rotating magnetic field generating circuit. As is well known, this rotating magnetic field is created by arranging multiple coils, for example two coils, so that the magnetic fields they create are perpendicular to each other, and each coil receives current with a phase difference of π/2. It can be obtained by flowing Usually, this coil drive frequency is put into practical use from 50 to 100 KHz. In the above-mentioned magnetic bubble memory, a higher coil drive frequency is required to enable high-speed writing and high-speed reading of stored data due to increased capacity, and the problems related to the skin effect described above must be adequately addressed. It won't happen. Now, for the manufacturing reason of making the finished outer diameter of the conventional Ritsu wire circular, as shown in FIG. 1a and FIG.
It is manufactured by using seven wires 1a to 1g and twisting six wires 1b to 1g around one wire 1a (concentric twist). In other words, one strand 1a placed at the center extends almost linearly, and the six surrounding strands 1b to 1g spirally surround the one strand 1a placed at the center. It is twisted into a shape and has an outer circumference 2 that is close to a circle. In addition, the strand 1b
A cross-sectional view of ~1g is shown in Figure 1c. Each strand is a self-adhesive magnet wire, and specifically has a structure in which a polyurethane insulating layer 4 is provided on the outer periphery of a copper conductor 3, and a thermoplastic resin adhesive layer 5 is further coated on the outer periphery. By the way, when considering the skin effect in a Ritsutsu wire, the skin effect of each strand is based not only on the self-current of the strand but also on the influence of the magnetic field due to the current flowing in the strands disposed in close proximity. the result,
In the above-described conventional wire, the six surrounding wires 1b to 1g have the same conditions, so the current densities are almost the same. However, the single wire 1a placed at the center is most affected by the skin effect, and its current density is smaller than that of the six surrounding wires. That is, since the structural arrangement of the seven strands as a whole is unequal, the current density distribution is different, resulting in an increase in loss resistance. Therefore, since the conventional concentrically twisted wire has a uniform current density, it cannot be said that the problem of the skin effect has been completely solved. Now, the present inventors, in view of the current situation,
Patent application No. 56-119051 for a Ritsutsu wire and coil that takes into consideration the uniformity of the current density distribution in response to the increased speed of the Ritsutsu wire, and reduces loss resistance due to the skin effect.
It was proposed in the issue. In this prior invention, in order to reduce the loss resistance due to the skin effect, a structure consisting of three strands is used as a basic unit, and this basic unit litz wire is further twisted by three strands N times (an integer of N≧2). configured,
It is characterized by twisting 3 to the Nth power of strands of wire. [Object of the invention] The present invention proposes an application example of the above-mentioned earlier application, and therefore, the purpose is to:
To provide a Ritsu wire and a coil that have a uniform current density distribution and reduce loss resistance due to the skin effect, in response to higher frequencies of current flowing through the Ritsu wire and coils and higher speeds of magnetic bubble memories. In particular, according to the present invention, a control signal line for temperature detection or magnetic field detection of the Ritsu wire or coil is provided in the remaining space of the Ritsu wire or coil created by making the current density distribution uniform. By including this, it is possible to provide a Ritsu wire and a coil that control the Ritsu wire or coil. [Summary of the Invention] The present invention provides a wire that is formed by twisting a plurality of insulated wires, in which an insulated shaft member is arranged at the center, and m wires (m≧
An integer of 3) is twisted to form a basic unit wire, three of the basic unit wires are used and further twisted, and this three-strand twisting is repeated N times (N is an integer of 2 or more). A high frequency wire is characterized in that it is formed by These wires are then used to manufacture coils. [Embodiments of the Invention] Before describing embodiments of the present invention, embodiments of the invention of the prior application will be briefly described. 2a, 8a, and 9a are embodiments of the invention of the earlier application, and FIG. 2a shows three strands 6a,
This is a wire made by twisting 6b and 6c, and the outer periphery of the finished wire is indicated by number 7. three strands 6a,
Since 6b and 6c are twisted evenly, they are structurally symmetrical. Fig. 8a shows an embodiment in which three basic unit wires shown in Fig. 2a are twisted, and Fig. 9a
This shows an example in which three more wires shown in FIG. 8a are twisted. That is, in the prior invention described above, by repeating three twists, the structural conditions of each strand are made uniform, and the current density distribution of the entire wire is made uniform at the level of the strands. Now, embodiments of the present invention will be described in detail below. The present invention is particularly different from the above-mentioned prior invention in that when constructing a wire, by arranging a shaft member at the center and twisting the strands so as to substantially circumscribe the shaft member, the strands have the same structure as each other. Focusing on having conditions,
The point is that the Ritsutsu wire is composed of three or more strands. FIGS. 2b to 2f are cross-sectional views showing six embodiments of the basic unit wire of the present invention. The most important point of the Ritsutsu wire of the present invention is that, as mentioned above, the m wires (m≧4, an integer) that make up the Ritsutsu wire are
They are arranged and twisted at symmetrical positions around the shaft member so that they have the same structural conditions, and the current density distribution of each strand is made uniform. Figure 2 b, c, d, e, and f are each 4
Book strands 8a to 8d, five strands 11a to 11
e, 6 strands 14a to 14f, 7 strands 17
This is a wire made by twisting strands a to 17g and 13 strands 20a to 20m, and the outer periphery of the finished wire is indicated by numbers 10, 13, 16, 19, and 22, respectively. These wires are coated with a high-bond adhesive layer around them, and have flexible shaft members 9 and 1.
It is formed by twisting 2, 15, 18 and 21 as the center. Therefore, as shown in FIG.
They are arranged radially with respect to shaft members 9, 15, 18 and 21, have the same structural conditions, and are bonded to these shaft members 9, 12, 15, 18 and 21. As mentioned above, this shaft member constitutes the axis when twisting each wire, and its diameter is determined by the number and diameter of the surrounding wires, and the outer circumference of the shaft member is determined by the number and diameter of the surrounding wires. By circumscribing each element wire, it also has the function of preventing the wire from deforming. An insulating material is used, and if an insulated wire having a conductor in the center is used, the conductor can be used as a control signal line as described later. Now, we will calculate the loss when a current density distribution due to the skin effect occurs in the conductor, and clarify the relationship between the current density distribution and high-frequency resistance. Now, consider a case where a current having a current density distribution J(γ) as shown in FIG. 4 flows through the conductor 100 shown in FIG. 3. When the radius of the conductor 100 is a, the current is l, the conductivity is σ, the resistivity is ρ, and the magnetic permeability is μ, the current density distribution J (γ) and the skin depth δ can be given by the following equations. Are known. ω: Angular frequency Here, if the total current flowing through the conductor is I, then I=∫ ^a/0 2πγJ(γ)dγ (3), and the maximum current density J _nax is becomes. Therefore, the loss P (=R(γ, θ)・i ² (γ, θ)・
l) is That's what I find. On the other hand, the loss P ₀ when a current I with a uniform current density flows through the conductor 100 in FIG. 3 is: P ₀ = R ₀ I ² = P・l/πa ²・I ² (6) Therefore, The loss ratio P/P ₀ is calculated from equations (5) and (6) by setting t=a/δ (7), then P(t)/P ₀ = t ² (2t-1+e ^-2t )/8( t-
1+e ^-t ) ² (8) Now, considering the high frequency resistance ratio R/R ₀ , R/R ₀ = RI ² /R ₀ I ² = P(t)/P ₀ (9) From this, R(t) /R ₀ =t ² (2t-1+e ^-2t )/8(t-
1+e ^-t ) ² (10) is obtained. In equation (10), when t=0, that is, equation (7), equation
When calculating the case of ω→0 from (2), it can be confirmed that R(0)=lim t→0R(t)=R ₀ (11) holds true. From equation (10), when t≫1 (12), R(t)/R ₀ ≈t/4 (13) From the above, the characteristics of equation (10) are shown in FIG. It can be seen from FIG. 5 that as the radius a of the conductor 100 exceeds the skin depth δ, the high frequency resistance increases. In addition, to indicate the degree of current density distribution, J _nax /
Think about the relationship between J _nio . From equations (1) and (7), the following relationship is obtained, which is shown in FIG. J _nax /J _nio = e ^t (14) When there is a uniform current density distribution without skin effect, t = 0 in equation (14), so it is confirmed that J _nax = J _nio holds true. can. As described above, from FIGS. 5 and 6, as the current density distribution J _nax /J _nio increases, the high frequency resistance R(t) increases in proportion to this. Therefore, the current density uniform in the conductor (J _nax /J _nio =
1), the high frequency resistance of the conductor can be minimized (R ₀ ). For example, in FIG. 6, for a certain t ₁ (ω ₁ , a ₁ ),
Ideally, by converting a single wire into a Ritsutsu wire,
The current density distribution J _nax /J _nio can be set to "1", and as a result, the high frequency resistance R can be set to the minimum value R ₀ . However, this is based on the assumption that a uniform current flows through each strand of the Ritsu wire, and in the case of the Ritsu wire shown in Figure 1b, uniform current does not flow. That's right. That is, the current density distribution in the B-B direction of the Ritsu wire shown in FIG. 1b is as shown in FIG. 7, and the current density distribution at the strand level is not made uniform. On the other hand, the wires shown in FIGS. 2b to 2f of the present invention are arranged symmetrically so that each wire has the same structural conditions, so the current density is uniform at the wire level. , and the high frequency resistance R can be set to the minimum value R ₀ . Now, FIGS. 8b to 8d show an embodiment in which n pieces (an integer of n≧3) of the basic unit wires shown in FIG. 2 are twisted. FIG. 8b shows the wire of the prior invention shown in FIG. 8a, which includes a shaft member 31 in the center, and has an outer periphery designated by numeral 32.
Further, FIG. 8c shows a structure in which three basic unit wires shown in FIG. 2c are twisted. Furthermore, FIGS. 9b to 9d show an embodiment in which P pieces (P≧3, an integer) of the wires shown in FIG. 8 are twisted. FIG. 9b shows the prior invention shown in FIG. 9a, which includes a shaft member 40 in the center of the wire. Furthermore, FIG. 9c shows a twisted wire using three wires shown in FIG. 8c, and this example includes a shaft member 42 in the center. Although the finished outer circumferential line is not particularly shown in the embodiment shown in FIG. 9, it is clear that it is circular. In addition, if we use the concept of the Ritsutsu wire shown in Fig. 2 b to f and use the Ritsutsu wire using the same strands,
It will be clear that many combinations are possible. That is, according to the present invention, the structural arrangement of each strand in the Ritsu wire is made equal by adopting the above-described twisting structure, and as a result, the influence of the skin effect due to adjacent strands on each strand is reduced. become equal, and the current flowing through each wire also becomes equal. Therefore,
The current density distribution of the entire Ritsutsu wire, which is made up of each strand, is made uniform at the level of the strands, and is not affected by the skin effect caused by adjacent strands, but only by the skin effect caused by the self-current. Become. Therefore, in the present invention, it is only necessary to consider the skin effect of the strands constituting the Ritsu wire, and the increase in loss resistance can be significantly suppressed compared to the conventional Ritsu wire. FIG. 10 shows an embodiment of a coil 50 manufactured using the above-mentioned wire. Fig. 11 shows a coil 51 manufactured by winding two layers of Ritsutsu wire.
FIG. 2 is a cross-sectional perspective view of a main part, and the arrow indicates the winding direction. Note that the shaft members 9, 12, 15, 18, 21,
Application examples of Nos. 31, 33, 40, 41 and 42 will be described. In general, for coils used in magnetic bubble memories and the like, it is desired to detect the temperature or magnetic field of the coil and control the device using the obtained detection signal, especially from the viewpoint of safety. In this case, in the present invention, since the shaft member passes through the core of the coil, it can be effectively used for the detection. That is, as a shaft member, for example,
If a wire having a conductor 18a at the center and an insulating layer and a high bond adhesive layer 18b at the periphery as shown in FIG. 1 is used, the conductor 18a can be used as a control signal line. For example, let's talk about temperature detection. It is well known that the resistance of a conductor varies slightly with temperature. Therefore, by passing a current through the control signal line at predetermined intervals and detecting a change in resistance due to a change in temperature as, for example, a change in voltage, the temperature of the coil can be reliably detected. As an example of using this temperature detection, when the temperature of the coil reaches a predetermined temperature,
It may cause the memory to stop working. [Effects of the Invention] Next, the effects of the present invention will be explained using characteristic diagrams. Figure 12 is a cross-sectional view of a conventional Ritutsu wire taken up to compare the characteristics with the _Ritztsu wire of the present invention. It has an outer circumference of 2n. FIG. 13 is an example of the use of a Ritsu wire for comparing the characteristics of a conventional Ritsu wire and a Ritsu wire according to the present invention, and shows a front view of the coil 52. FIG. 14 shows the frequency characteristics of the loss resistance for the coil in order to compare the effects of the present invention with those of the prior art. Table 1 shows the basic conditions for each curve shown in FIG.

[Table] Curve 62 in FIG. 14 is for the Ritz wire according to the present invention, and is the frequency characteristic of the coil shown in FIG. 13 manufactured using the Ritz wire having the cross-sectional structure shown in FIG. 8A. . Further, a curve 61 is for a conventional wire, and is the frequency characteristic of a coil shown in FIG. 13 manufactured using a finished wire having the cross-sectional structure shown in FIG. 12. Furthermore, curve 60
is the frequency characteristic of a coil formed from a single wire having a wire diameter of 3a and a cross-sectional area of 9S. As is clear from FIG. 14, the rise of the loss resistance ratio R/R ₀ (R: high frequency resistance, R ₀ : DC resistance) with respect to frequency is better in the Ritz wire 62 according to the present invention than in the conventional Ritz wire 61. In the present invention, the slow rise frequency, that is, the rise frequency at which the loss resistance rapidly increases when the diameter of the wire and the skin depth become approximately the same, has been improved to become larger in the present invention, and the effects of the present invention are clearly manifested. There is. As explained in detail above, the present invention makes it possible to equalize the structural arrangement of each wire composing a Ritsutsu wire, and to significantly suppress the increase in loss resistance caused by the skin effect of a single wire or coil. can. This makes it possible to drive high-speed drive coils such as magnetic bubble memory with low loss.
Its industrial value is extremely great.

[Brief explanation of drawings]

Figure 1 is a drawing regarding the conventional Ritutsu wire,
Figure 1a is an external perspective view, Figure 1b is A of Figure 1a.
-A line sectional view, FIG. 1c is a sectional view of the strands constituting the wire of FIG. 1b. FIG. 2a is a cross-sectional view of the Litz wire of the prior invention by the present inventors.
FIGS. 2b to 2f are cross-sectional views showing five embodiments of the basic unit wire of the present invention. Figure 3 is a perspective view of a single line, Figure 4 is a current density distribution diagram of a single line, Figure 5 is a characteristic diagram of high frequency resistance R(t), Figure 6 is a characteristic diagram of current density distribution J _nax /J _nio , FIG. 7 is a current density distribution diagram of the Ritz wire. FIG. 8a is a cross-sectional view of the Litz wire of the prior invention by the present inventors. Figure 8b
-c are sectional views showing three embodiments of the Ritz wire according to the present invention, which are formed by further twisting the basic unit Ritz wire shown in FIG. 2. FIG. 9a is a cross-sectional view of the Litz wire of the prior invention by the present inventors. 9b to 9c are cross-sectional views showing three embodiments of the litz wire formed by further twisting the litz wire shown in FIG. 8. FIG. FIG. 10 is a perspective view of a coil manufactured using the Ritsu wire according to the present invention, and FIG. 11 is a partially cross-sectional perspective view of a two-layer coil. Fig. 12 is a sectional view of a conventional Ritsu wire for comparing characteristics with the present invention, Fig. 13 is an external view showing the coil shape, and Fig. 1
Figure 4 is a frequency characteristic diagram of the loss resistance ratio R/R ₀ . 8a-8d, 11a-11e, 14a-14
f, 17a to 17g, 20a to 20m... strand,
9, 12, 15, 18, 21...Shaft member, 18a
...Conductor, 18b...Insulating layer and adhesive layer, 31,
33, 40, 41, 42... Shaft member, 50, 51
……coil.

Claims (1)

[Claims] 1. In a wire formed by twisting a plurality of insulated wires, an insulated shaft member is arranged at the center, and m wires (m≧3) are arranged around the shaft member. An integer) of strands are twisted to form a basic unit wire, and three of the basic unit wires are used and further twisted, and these three are twisted N times (N is an integer of 2 or more).
A high frequency wire that is repeatedly formed. 2. The high frequency wire as claimed in claim 1, wherein the shaft member has an insulating layer formed around it and a control signal line conductor formed in the center. 3. The high frequency wire according to claim 2, wherein an adhesive layer is formed on the outermost periphery of the insulating layer of the shaft member. 4. The high frequency wire according to claim 2, wherein the control signal conductor of the shaft member is used for temperature detection. 5 In a coil using a Ritsutsu wire formed by twisting a plurality of insulated wires, an insulated shaft member is placed at the center, and m wires (m≧3, an integer) are arranged around the shaft member. The basic unit wires were twisted to form a basic unit wire, three of the basic unit wires were used and further twisted, and these three twists were repeated N times (N is an integer of 2 or more) to form a wire. A coil manufactured using high-frequency Ritsutsu wire.