JPS648434B2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to a coaxial cable used to supply power to various devices operated at extremely low temperatures, and a connection structure of this coaxial cable. It is.

(Prior Art) Conventionally, when power is supplied to equipment operating under this kind of extremely low temperature, the equipment is kept airtight when connected to the power supply cable, and the cold air inside the equipment is kept away from the outside. There is no effective means to prevent leakage to the equipment, and when the equipment is operated, external heat such as room temperature is conducted to the equipment through the cable, causing an increase in internal temperature, or The enclosed cooling liquid infiltrates the inside of the cable to be connected, causing volatilization and disappearance of the enclosed cooling liquid.

(Objects and Structure of the Invention) The coaxial cable and the connection structure of the cable according to the present invention are designed to suppress the transfer of external heat as much as possible when operating various devices at such extremely low temperatures. It is designed to suppress interference and destruction of high-frequency electrical signals as much as possible, and at the same time prevent volatilization and wear and tear of liquefied helium, etc. sealed as a cooling medium in devices that are connected to the coaxial cable. The structure consists of a cylindrical outer conductor and an inner conductor enclosed within the outer conductor via an insulating material such as Teflon resin.The free end of the inner conductor is exposed at the cut end of the coaxial cable. , to be fitted into a thin connecting conductive rod having a bottomed pore, and on the circumferential surface of the thin connecting conductive rod except for the free end, and on a part of the circumferential surface of the exposed insulating material and external conductor. Insulating pieces divided into a plurality of pieces are hermetically fitted, and a conductive sleeve is placed on the circumferential surface of the tightly fitted insulating piece and on the circumferential surface of the external conductor.

(Example) Typical examples of the cryogenic coaxial cable and the connection structure of the cable according to the present invention will be explained below with reference to the drawings. A is a cable developed especially for cryogenic wiring, and the inner conductor 1 The conductor 2 is made of an alloy of 30% nickel and 70% copper (hereinafter referred to as cypronickel) or stainless steel, and the intermediate resin insulator 3 is made of a material with excellent insulation and weather resistance properties, especially cold resistance properties, such as Teflon resin. It is constructed as a thing.

Note that the insulator 3 such as Teflon resin used has sufficient heat insulation properties and does not pose any particular problem, but measures for heat conduction in the inner conductor 1 and outer conductor 2 are especially taken into consideration. In particular, it is ideal to use stainless steel, which has a low thermal conductivity, to intentionally suppress heat conduction.

In other words, the amount of heat conducted from the outside of the device to the inside of the device using the cable as a heat conduction medium is far greater than the amount of heat generated due to the increase in internal resistance due to the decrease in electrical conductivity. Particularly important was the isolation of heat generated by the process.
In this respect, Cypronickel or stainless steel materials were particularly consciously used in place of copper and silver materials.

Cable A with such characteristics should be wired to the target cryogenic equipment in a completely airtight manner to ensure that the encapsulated liquefied helium or liquefied nitrogen does not infiltrate, leak, vaporize, or volatilize. It is designed to ensure that extremely low temperatures can be maintained through repeated use of these sealed gases.

However, in the coaxial cable A, which has the purpose of reducing as much as possible interference and destruction of signals due to the input of high-frequency electric signals, as well as heat conduction as described above, the cable between the outer conductor 2 and the resin insulating material 3 is Similarly, a slight gap is likely to be created between the insulating material 3 and the internal conductor 1, and when the device and the cable A are directly connected, the enclosed coolant which is caused by this slight gap. There were concerns that the infiltration or loss of gas or the dissipation of vaporized gas would occur separately.

In the present invention, in addition to providing such a unique cable A, it is possible to prevent such leakage or dissipation from the cut end of the cable A, especially from the connection part, and to prevent dilution of the sealed gas due to the inflow of air from the outside. The purpose of the present invention is to provide a connector B that reliably suppresses internal temperature rise and internal temperature rise.

The connector B has one end with a pointed head,
A thin connecting conductive rod 4 has a bottomed hole 4a for tightly fitting and fixing the internal conductor 1 toward the pointed end from the other end; A different diameter sleeve 5 having an engaging edge flange 5a on the inner side and a female screw 5b on the inside of the other end, and a thin connecting conductive rod 4 which is fitted into the sleeve 5 and connected at the end. An insulating piece 6 having a fitting hole 6a in the center of the longitudinal direction to be tightly fitted, and a female screw 5 in the sleeve 5.
b, and the different diameter stepped portion 5 in the cannula 5.
Nut 7 having a cylindrical rising wall 7a reaching c.
The nut 7 is fitted into the rising wall 7a of the nut 7, and is inserted through the insertion hole 8a of the thin connecting conductive rod 4.
and an insulating piece 8 having an enlarged diameter hole end 8a into which the outer circumferential collar 4b of the thin connecting conductive rod 4 fits, and the other end of the sleeve 5 where the nut 7 is attached is fixed with a spring 10. The coupling 9 is rotatably fitted and has a female screw 9a provided on the inner surface protruding from the sleeve 5.

Connector B made of such material is connected to cable A.
Attached to one cut end of the cut end, it prevents infiltration, leakage, vaporization, and dissipation of helium liquid or gas from the cut end, and also reliably prevents air from entering from outside. In order to achieve this purpose, first, the cut end of the cable A is inserted into the hole 7b made in the nut 7, and then the piece 8 is fitted onto the cable A, and then the outer conductor 2 at the inserted end is inserted. and resin insulation material 3
The internal conductor 1 and the insulating material 3 are exposed in stages.

The internal conductor 1 taken out in this way is tightly fitted into the hole 4a of the connecting conductive rod 4 and brazed to form a conductive connector for the internal conductor 1, and then,
Pieces 6 and 8 are each tightly fitted onto the thin connecting conductive rod 4, and these pieces are inserted into the sleeve 5. The piece 6 comes into contact with the collar 5a of the sleeve 5, and the nut 7 is inserted into the sleeve 5. By pushing along the female screw 5b, the piece 8 pushes the flange 4b of the connecting conductive thin rod 4 into the enlarged diameter hole end 8a of the piece 8, and at the same time the piece 6 is pushed by the flange 4b toward the flange 5a of the mantle 5. They are integrally attached to each other.

The inner conductor 1 of the cable A is connected to the connecting conductive thin rod 4, and the outer conductor 2 is connected to the nut 7, the sleeve 5, the coupling 9, etc. which are fitted onto the outer conductor 2 and connected to each other. is used as a transmission medium, and is connected to the inner conductor or outer conductor of another coaxial cable, respectively.

Therefore, the nut 7, sleeve 5, coupling 9, etc. are made of a material with relatively good conductivity, such as copper alloy.

In addition, piece 6 in the story is made of a resin material sold by Emerson & Cumming Japan under the product name Stycast 1266, and piece 8 is made of Teflon material, both of which have insulating properties. This is a member that also has a sealing function.

(Effects of the invention) Recently, there has been a need to speed up the operation of equipment at extremely low temperatures, such as -200°C to -270°C, which approach absolute temperatures of 0° (0°K), especially the speeding up of memory input/output operations in computer equipment. There has been a particular demand for the development of cryogenic devices filled with liquefied substances such as nitrogen gas or helium gas, and the cable and connector according to the present invention can immediately meet such demands. By attaching the connector B to the connecting end of the cable A as shown above, it is possible to connect the generated gap between the internal conductor 1 and the insulating material 3 of the cable A. The conductive thin rod 4 and the pieces 6, 8 can be completely sealed, and at the same time the outer conductor 2 and the insulating material 3 can be sealed.
Between pieces 6, 8 and Natsu 7
It can be reliably sealed with the rising wall 7a of the cable A, and the infiltration, loss or dissipation of the refrigerant from the cut end of the cable A can be reliably prevented, and the equipment in which the refrigerant is sealed can be reliably sealed. This reliably prevents the inflow of air from the outside of the device, thereby avoiding problems such as an increase in electrical resistance due to a rise in temperature inside the device.

Therefore, the cable and connector according to the present invention have a coaxial cable structure that reduces electrical resistance and is optimal for equipment operation at extremely low temperatures, and provides heat insulation and sealing properties when connecting the coaxial cable. The present invention provides a wiring connection structure that can be obtained.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a typical embodiment of the present invention in which a coaxial cable is connected to a connector, and FIG. 2 is a partially cutaway side view of the end of the coaxial cable according to the present invention. In the figure, 1...internal conductor, 2...outer conductor, 3...resin insulating material, 4...connecting conductive thin rod, 5...mantle tube, 6...insulating piece, 7...nut, 8...insulating piece, 9...coupling, 10 shows a spring.

Claims (1)

[Claims] 1. The free end of the exposed protruding inner conductor at the cut end of a coaxial cable, which has a cylindrical outer conductor and an inner conductor sealed inside the outer conductor via an insulating material such as Teflon resin, is It is made to fit into a thin connecting conductive rod having a hole, and
Insulating pieces divided into one or more pieces are hermetically fitted onto the circumferential surface of the thin connecting conductive rod excluding the free end and a portion of the exposed circumferential surface of the insulating material and the external conductor;
A connection structure in a cryogenic coaxial cable characterized by a conductive sleeve tightly fitted over the circumferential surface of the tightly fitted insulating piece and the circumferential surface of the outer conductor.