JPS6248406B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention effectively dissipates the amount of heat generated by the repeater circuit unit in the optical submarine repeater case to the repeater case, prolonging the life of the semiconductor laser, and This relates to a structure that protects optical elements such as electronic circuits and lasers within the unit by alleviating vibrations and shocks transmitted to the unit.

The circuit unit inside the optical submarine repeater housing consumes about 10W of power per system (up and down), and the amount of heat generated by this causes the atmospheric temperature inside the repeater circuit unit to rise. The lifespan of the laser mounted in the repeater circuit unit will deteriorate if the ambient temperature around the laser is high.
The lower the ambient temperature, the longer the life. On the other hand, when an optical submarine repeater is installed on the seabed at a depth of several hundred meters or more, the outer surface of the repeater casing has a temperature of approximately 2 to 3° C., which is the water temperature below the seafloor. Therefore, it is desirable to efficiently transmit the heat generated by the repeater unit to the outer surface of the repeater housing so that the repeater housing functions as a heat exchanger.

Figure 1 shows the buffering and heat dissipation structure of a conventional repeater circuit unit. 1 is the cylinder of the repeater housing, 2 is the cushioning rubber, 3 is the insulator of the repeater circuit unit, and 4 is the insulator of the repeater circuit unit.
is a repeater circuit, and 5 is a dry inert gas. According to this structure, vibrations and shocks are dampened by the cushioning rubber 2, and heat is dissipated by heat conduction by dry inert gas (generally _N2 gas). Since the thermal conductivity of both the buffer rubber 2 and the inert gas 5 is extremely low, the heat dissipation effect in this structure is extremely low. In order to improve this, there is also a plan to mix metal powder into the buffer rubber 2 and use He gas, which has relatively high thermal conductivity, as the inert gas 5. In this case, the heat dissipation effect is considerably greater than in the former case. However, the rubber material itself contains a considerable amount of adsorbed gas, and when used in a repeater housing, it causes contamination of the dry inert atmosphere within the housing. Furthermore, since He gas has a lower dielectric strength than other inert gases, the combination of the two may cause the insulation of the circuit to deteriorate and break down.

In order to improve the above problems, a structure using metal springs as a heat dissipation structure has been proposed (see Japanese Patent Application No. 177141/1982). In addition to improving heat dissipation characteristics, metal springs also have the function of absorbing the vibrations and shocks that the repeater housing receives during installation, thereby maintaining the reliability of optical circuit components. When vibrations and shocks are absorbed by a metal spring, the rate at which vibrations are transmitted, that is, the vibration transmission rate λ, is expressed by the following equation.

Here, f is the vibration frequency, ν is the natural frequency of the spring, and α is the damping index.

Using this formula to illustrate the relationship between λ and f, Figure 2
become that way. Here, when α/ν is small,
is when α/ν is large. As is clear from this figure, at f√2, the vibration transmissibility λ is less than 1, and the vibration is attenuated, but the vibration is amplified because it resonates in the vicinity of f〓ν. Therefore, when absorbing vibrations and shocks with a metal spring, it is necessary to determine the natural frequency of the spring according to the frequency characteristics of the vibrations and shocks applied to the repeater housing.

The present invention provides a heat dissipation/buffer structure for an optical submarine repeater in which an optimal buffering effect can be obtained by using springs with different natural frequencies depending on the magnitude of vibrations and shocks applied to the repeater housing. It is something.

The present invention will be explained in detail below.

The repeater housing passes through each part of the installation mechanism, as an example is shown in FIG. Here, 12 is a cable tank, 13 is a repeater, 14 is a trough, 15 is a DO/HB (draw-off holdback gear) consisting of a caterpillar, 16 is a cable engine drum, 17 is a dynamo, and 18 is a bow sheave.
Figure 4 shows an example of measuring the maximum value of the shock that the repeater housing received at each part during actual installation. The solid line is the radial direction, and the dotted line is the axial direction. In this way, the repeater housing is subjected to various shocks at various parts, but in reality, large shocks exceeding 10G are only a few cases, and most of them are
It continues to receive small vibrations and shocks of 5G or less throughout the installation process. Therefore, while the primary purpose of buffering is to alleviate the maximum impact, it is essential for optimal design to alleviate even smaller impacts that continue to be received.

FIG. 5 shows an example of measuring the frequency characteristics of the impact shown in FIG. 4. This result shows that the pattern of frequency characteristics differs depending on the location. Therefore, in order to effectively buffer the impact at each location, it is necessary to change the natural frequency ν of the buffer spring depending on the frequency characteristics of each impact.

FIG. 6 is an embodiment of the present invention. In the figure, 4 is a repeater circuit unit, and 3 is an insulator. The area around this insulator 3 is covered with a metal cylinder 9 in order to improve the heat radiation exchange effect, and this cylinder 9 and the repeater housing cylinder (Figure 1-1)
A first metal spring 8 is arranged in the gap between the two so as to be in contact with both. The metal spring 8 is fixed to the metal cylinder by 11b. If the heat dissipation effect can be obtained only with the metal spring, the metal cylinder 9 may be omitted.
The metal spring 8 is made of a material with excellent thermal conductivity, such as copper or copper alloy, and has a low spring stiffness (i.e., a small value ν) so that it deforms in response to small impacts. Form it. If this spring 8 receives a shock during installation,
In the case of a weak impact, it deforms and absorbs the impact. If a stronger impact is received, the spring 8 will be greatly deformed and will come into contact with the second metal spring 10. Spring 10 is 1
It is fixed to the metal cylinder 9 at 1a, and the free end is normally not in contact with the spring 8. This spring 10 deforms together with the spring 8 to absorb strong impact. In this case, the combined rigidity of the spring 8 and the spring 10 is set to a strength that can alleviate the maximum impact during installation.
Further, depending on the case, the spring 8 and the spring 10 may have the same natural frequency, and the combined natural frequency may be set to a value that alleviates the maximum impact when the springs 8 and 10 are deformed as a unit. Indicates the maximum value of impact at the cable laying mechanism.
Looking at the frequency characteristics of DO/HB shock in Figure 5a,
Since the first minimum value in the low frequency part is approximately 200Hz, the composite ν of spring 10 and spring 8 is
200/√2≒140Hz, and ν of the spring 8 should be set to 100Hz or less. With such a structure, different springs work depending on the strength of the impact during installation, and the spring 8 is always in contact with the repeater housing cylinder 1, so that heat dissipation characteristics are also excellent.

In FIG. 6, the spring is divided in the length direction of the cylinder, but the spring may be integrated in the length direction.

Other embodiments are shown in FIGS. 7 and 8.

In the example described above, the springs 8 and 10 are fixed at the outer periphery of the metal cylinder 9;
It is also possible to reverse the spring structure of 10 and fix these springs 8 and 10 on the inner periphery of the repeater housing 1, and as shown in FIG. It is also possible to separate it into a metal cylinder 9. In either case, substantially the same buffering effect and heat dissipation effect as in the embodiments shown in FIGS. 6 to 8 can be obtained.

Furthermore, in the example described above, the spring has a two-stage structure. Of course, a multi-stage structure of three or more stages as shown in FIG. 10 is also possible. If there are multiple stages, the natural frequency can be changed by the number of stages of the spring, and an even better damping effect can be expected. This is actually determined by the degree of clearance between the repeater circuit unit and the repeater housing cylinder.

As described above, the present invention makes the buffer of the repeater circuit unit a multi-stage structure of metal springs with different natural frequencies, thereby effectively dissipating the amount of heat generated from the repeater circuit and during installation. This makes it possible to absorb vibrations and shocks of various sizes in the most efficient manner. This has the effect of realizing a highly stable system that is free from the risk of deteriorating the reliability of optical elements and electric circuits.

[Brief explanation of the drawing]

Figure 1 is a sectional view of a conventional optical repeater housing showing the heat dissipation/buffer structure inside the housing, Figure 2 is a characteristic diagram showing the relationship between the vibration transmissibility and vibration frequency of a metal spring, and Figure 3
is a system diagram showing each cable laying mechanism inside the cable laying ship, Figure 4 is a spectrum diagram showing the magnitude of the impact received by the repeater housing during laying, Figure 5 is a typical frequency characteristic diagram of the impact received at each part, Figure 6 , 7, 8, 9, and 10 are perspective views or sectional views showing one embodiment of the present invention. 1... Repeater housing cylinder, 2... Buffer rubber, 3...
... Insulator, 4 ... Repeater circuit unit, 5 ... Inert gas, 8, 10 ... Metal spring, 9 ... Metal cylinder, 11a, 11b ... Fixed position, 12 ... Cable tank, 13 ... Repeater, 14...trough,
15...DO/HB, 16...Cable engine drum, 17...Dynamo, 18...Bow sheave.

Claims (1)

[Scope of Claims] 1. In a heat dissipation/buffer structure disposed on the outer periphery of a repeater circuit unit in an optical submarine repeater housing, the outer periphery of an electrical insulator located on the outer periphery of the repeater circuit unit and the repeater casing. a second metal spring having a portion contacting and fixed to one of the outer periphery of the electrical insulator and the inner periphery of the repeater casing in a gap between the inner periphery of the body and the inner periphery of the repeater casing; At least one of the outer periphery of the electric insulator or a first metal spring that contacts the second metal spring and is fixed to the second metal spring has a gap between the free end sides of both springs. When a small impact is received, only the free end of the first metal spring deforms, and when a large impact is received, the first metal spring deforms and comes into contact with the second metal spring. A heat dissipation/buffer structure for an optical submarine repeater, characterized in that both springs are configured to deform together. 2. The heat dissipation/buffer structure for an optical submarine repeater according to claim 1, wherein at least one of the first metal spring and the second metal spring has a multi-stage structure. 3. In a heat dissipation/buffer structure disposed on the outer periphery of a repeater circuit unit in an optical submarine repeater casing, a gap between the outer periphery of a metal cylinder located on the outer periphery of the repeater circuit unit and the inner periphery of the repeater casing. a second metal spring, a portion of which is fixed in contact with one of the outer periphery of the metal cylinder and the inner periphery of the repeater casing; A first metal spring that is in contact with one or the second metal spring and is fixed to the other or the second metal spring is arranged with a gap between the free end sides of both springs, and receives a small impact. when the first metal spring is deformed, only the free end of the first metal spring is deformed;
Heat dissipation for an optical submarine repeater, characterized in that when receiving a large impact, the first metal spring deforms and comes into contact with the second metal spring, causing both springs to deform together. Buffer structure. 4. The heat dissipation/buffer structure for an optical submarine repeater according to claim 3, wherein at least one of the first metal spring and the second metal spring has a multi-stage structure.