JP2930464B2 - Detachable power lead and superconducting magnet device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a detachable power lead for supplying an exciting current to a superconducting coil and a superconducting magnet device using the detachable power lead.

[0002]

2. Description of the Related Art Conventionally, as a power lead for supplying an exciting current to a superconducting coil of a superconducting magnet device, a conventional power lead made of copper or the like has been used. However, a material such as copper constituting the power lead has a drawback that the amount of heat penetration due to heat conduction is extremely large because it is a good heat conductor.

As a remedy, there has been proposed a detachable power lead which disconnects the power lead when not in use and cuts off the heat path between the normal temperature part and the low temperature part. FIG. 3 is a cross-sectional view of a connecting portion showing an example of a conventional detachable power lead described in, for example, a low-heat-intrusion detachable power lead (37th Low-temperature Engineering Research Conference Proceedings, P.136, 1987).
In the figure, 8 is a lead cable, 9 is a detachable movable multi-pin connector, 10 is a detachable fixed multi-pin connector, 11 is a bellow that secures the movable stroke of the movable multi-pin connector 9, 12 is the movable and multi-pin connectors. A structure supporting the fixed-side multi-pin connectors 9 and 10, a support rod 13 supporting the entire attaching / detaching portion, a driving helium gas pipe 14 for expanding and contracting the bellows 11, and a driving helium gas 15 Compression / vacuum pump for exhausting
This is a gas control system including a buffer, a valve, and the like.

Next, the operation of the above-mentioned conventional detachable power lead will be described. First, a compressed gas of helium gas is sent into the bellows 11 via a driving helium gas pipe 14 by a gas control system 15 placed at a room temperature part. The bellows 11 is extended by the compressed gas sent, the movable multi-pin connector 9 moves to the fixed multi-pin connector 10, the movable multi-pin connector 9 is mounted on the fixed multi-pin connector 10, and the superconducting coil Is supplied with an exciting current.

After the superconducting coil operates in the permanent current mode, the gas control system 15 exhausts the helium gas in the bellows 11 through the driving helium gas pipe 15. The bellows 11 contracts due to the exhaust of the helium gas, the movable multi-pin connector 9 is detached from the fixed multi-pin connector 10, and becomes non-energized, and is in a thermally insulated state.

The conventional detachable power lead is a bellows 1
When the bellows 11 is expanded and contracted by sending and discharging compressed gas into and out of the housing 1, the movable multi-pin connector 9 and the fixed-side multi-pin connector 10 are attached and detached. After the current is passed, the superconducting coil is operated in the permanent current mode, the power lead is removed, and the thermal intrusion path is cut off to reduce the infiltration heat.

In the above-mentioned conventional detachable power lead,
Movable and fixed side multi-pin connector 9
By supporting the movable side and fixed side multi-pin connectors 9 and 10 with the structure 12 in a state where the positions 10 are aligned, the movable side and fixed side multi-pin connectors 9 and 1 are supported.
It suppresses the increase in contact resistance in the detachable part when mounting and dismounting 0, and suppresses heat generation during energization. Furthermore, using a multi-pin connector, the contact resistance is suppressed, and the energizing current per lead is reduced. As a result, heat generation due to contact resistance is suppressed.

[0008]

As described above, in the conventional detachable power lead, the movable and fixed multi-pin connectors 9 and 10 are supported and fixed by the structure 11 and the structure 11 is supported by the support rod 13. Because it is supported and fixed, even if the detachable part of the detachable power lead is cut off, the support rod 13 is connected to the room temperature part. Even if a low heat conductive material is used for the support rod 13, heat enters through the support rod 13. In addition, the current flowing per pin decreases with the use of multi-pins. However, when the number of pins increases, positioning at the time of mounting becomes difficult, and the pin diameter becomes thinner, resulting in lower strength. There has been a problem that breakage of the pin occurs.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and can reduce the contact resistance between pins when mounting and dismounting, increase the current flowing per pin, and reduce the heat when detaching. It is an object of the present invention to obtain a detachable power lead that can reduce intrusion, and to provide a superconducting magnet device using the detachable power lead.

[0010]

According to a first aspect of the present invention, there is provided a detachable power lead including a fixed portion provided with a first pin, and a second pin fitted to the first pin. A detachable power lead that includes a detachable portion facing the provided movable portion and opens and closes an electrical connection by fitting and removing first and second pins by moving the movable portion. A guide pin having one of the fixed part and the movable part is provided, and a guide hole engaging with the guide pin by the movement of the movable part is provided on the other of the fixed part and the movable part. Sum L of distance between taper and length of tapered part
₁ is such that L ₁ ≦ L ₂ with respect to the distance L ₂ between the first pin and the second pin.

In a superconducting magnet device according to a second aspect of the present invention, a power lead for supplying an exciting current to a superconducting coil is provided with a fixed portion provided with a first pin, and a power lead opposed to the fixed portion. A movable portion provided, a second pin provided on the movable portion and fitted to and disengaged from the first pin by the movement of the movable portion, and a guide provided on one of the fixed portion and the movable portion and having a tapered portion at a distal end portion. A pin, a guide hole provided on the other of the fixed portion and the movable portion, the guide hole being engaged with the guide pin by the movement of the movable portion, and the distance between the tip of the guide pin and the entrance of the guide hole, the length of the tapered portion, and the sum L ₁ of, with respect to the distance L ₂ between the first pin and the second pin, it is an detachable power lead to L ₁ ≦ L _2.

[0012]

[Action] In the first aspect of the invention, the sum L ₁ of the length of the distance and the tapered portion between the inlet of the guide hole and the front end portion of the guide pin, between the first pin and the second pin The first and second pins, guide pins, and guide holes are provided in the fixed portion and the movable portion, respectively, such that L ₁ ≦ L ₂ with respect to the distance L ₂ . When the tapered portion of the guide pin is guided and inserted into the guide hole, the fixed portion and the movable portion are securely aligned, and the subsequent fitting contact between the first pin and the second pin is reliably performed smoothly. .

[0013] In a second aspect of the present invention,
The sum L ₁ of the distance between the tip of the guide pin and the entrance of the guide hole and the length of the tapered portion is L ₁ ≦ L _{2 with} respect to the distance L ₂ between the first pin and the second pin. Since the first and second pins, the guide pin, and the guide hole use detachable power leads provided on the fixed part and the movable part, respectively, the movable part moves to guide the tapered part of the guide pin. At the time when the guide portion is inserted into the hole, the fixed portion and the movable portion are securely aligned, and thereafter, the fitting contact between the first pin and the second pin is reliably and smoothly performed, and the contact resistance is suppressed to a small value. As a result, the conduction current per pin can be increased, and furthermore, when the power lead is detached, the heat intrusion path from the room temperature portion is cut off.

[0014]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. Embodiment 1 FIG. FIG. 1 is a sectional view of a detachable portion of a detachable power lead showing an embodiment according to the first invention of the present invention. In the drawing, reference numeral 1 denotes a movable female pin as a second pin which is, for example, a B_N connector (a socket type of Salton Co., Ltd.), and 2 denotes a first pin which is, for example, an S_N connector (a plug type of Solton Co., Ltd.) Fixed side male pin,
Reference numeral 3 denotes a guide pin having a tapered portion 3a at the tip end, reference numeral 4 denotes a chamfered inlet port, and a guide hole for guiding and introducing the guide pin 3. Reference numeral 5 denotes a movable female pin 1 and the guide pin 3 integrated. A movable connector 6 as a movable portion made of an electrically insulating material, 6 is a fixed connector as a fixed portion made of an electrically insulating material integrating the fixed male pin 2, and the fixed connector 6 includes: A guide hole 4 is provided. Numerals 7a, 7b and 7c are nuts for fixing the movable female pin 1, the fixed male pin 2 and the guide pin 3 to the movable and fixed connectors 5 and 6, respectively.

In the detachable power lead according to the first embodiment, the movable female pin 1 and the guide pin 3 are opposed to the fixed male pin 2 and the guide hole 4, respectively, and the distal end of the guide pin 3 and the fixed connector 6 are connected to each other. the distance between the (entrance of the guide hole 4) (L ₃₎ and the length of the tapered portion 3a (L ₄₎
The sum L ₁ and, as the distance L ₂ between the movable-side female pin 1 and the fixed male pin 2, a relationship of L ₁ ≦ L _2, the movable female pin 1, the fixed-side male pin 2, the guide pin 3. The movable side and fixed side connectors 5 and 6 are respectively arranged and configured.

Next, the operation of the first embodiment will be described. The movable connector 5 is driven by a driving mechanism (not shown).
Since it is moved in the direction of the fixed connector 6 and L ₁ ≦ L ₂ , the guide pin 3 first enters the guide hole 4.
Here, even if the positions of the guide pin 3 and the guide hole 4 are shifted, the tapered portion 3a is guided by the guide hole 4 and inserted into the guide hole 4, and the tapered portion 3a is completely inserted into the guide hole 4. At this point, the alignment between the movable connector 5 and the fixed connector 6 is completed. Further, when the movable connector 5 is continuously moved in the direction of the fixed connector 6, the movable female pin 1 is moved.
Starts to contact the fixed-side male pin 2. At this time, since the positioning of the movable side and fixed side connectors 5 and 6 has been completed, the movable side female pin 1 is fitted and mounted on the fixed side male pin 2 while maintaining an extremely good contact state.

Next, the movable connector 5 is driven by a driving mechanism.
Is moved in a direction to separate the movable female pin 1 from the fixed connector 6, and the movable female pin 1 is separated from the fixed male pin 2.

Here, a test apparatus was prepared using six B10N and six S10N contacts as the movable female pin 1 and the fixed male pin 2, respectively, at a liquid helium temperature (about -269 ° C. under one atmosphere). When measured, 50
The resistance of the attachment / detachment part when the current is 0 A is 50 to 10 per location.
A contact resistance as small as 0 μΩ was measured, and this value did not change even after several tens of detaching operations by driving the motor were repeated.

As described above, according to the first embodiment, the sum (L ₃ ) between the tip of the guide pin 3 and the fixed connector 6 and the length (L ₄ ) of the tapered portion 3a (L ₄ ). L ₁ ) ≧
Distance between the movable female pin 1 and the fixed male pin 2 (L
₂ ), the movable connector 5 is provided with the guide pin 3 having the movable female pin 1 and the tapered portion 3a, and the fixed connector 6 is provided with the fixed male pin 2 and the guide hole 4. The engagement between the guide pin 3 and the guide hole 4 ensures that the movable female pin 1 and the fixed male pin 2 are aligned with each other, and that the contact resistance of the movable female pin 1 and the fixed male pin 2 is reduced regardless of the number of the movable female pin 1 and the fixed male pin 2. A small and reliable connection can be achieved, a current value per pin can be increased, and there is an effect that a highly reliable detachable power lead can be obtained with no increase in contact resistance due to detachment, no breakage of the pin.

Embodiment 2 FIG. FIG. 2 is a sectional view of a superconducting magnet device according to a second invention of the present invention. In the figure, 20
Is a vacuum chamber of the superconducting magnet device, 21 is a first radiant heat shield, 22 is a second radiant heat shield, 23 is a helium tank, 2
4 is a superconducting coil housed in a helium tank 23, 25
Is a liquid helium for cooling the superconducting coil 24, 26 is an evaporating gas of the liquid helium 25, 27 is a droplet formed by cooling the evaporating gas 26 again, 28 is a port leading to the helium tank 23, 29 is a first stage heat stage. 29a, second heat stage 29b, and third heat stage 29c
Is a three-stage Gifford-McMahon refrigerator, and 30 is a detachable power lead according to the first embodiment disposed in the helium tank 23.

In the detachable power lead 30, the fixed connector 6 is supported and fixed on the inner wall surface of the helium tank 23, the fixed male pin 2 is connected to the superconducting coil 24, and the movable female pin 1 is made of, for example, a copper tube. The current lead 30a is formed by being connected to the normal temperature portion by the above-described method, and the movable connector 5 is connected to a drive mechanism (not shown).

Next, the operation of the second embodiment will be described. First of three-stage Gifford McMahon refrigerator 29
-Stage heat stage 29a and second-stage heat stage 2
9b, the first and second radiant heat shields 21 and 22 are cooled, and the evaporative gas 26 is cooled and liquefied again by the third heat stage 29c via the helium tank 23.
Heat intrusion from the room temperature section to the cryogenic section is suppressed by the vacuum layer 20 and the first and second radiant heat shields 21 and 22. The superconducting coil 24 is cooled by the liquid helium 25 and is kept at a very low temperature.

Here, the movable side connector 5 is driven by the driving mechanism.
Is moved to the fixed connector 6 side, and the tip of the guide pin 3 enters the guide hole 4. Even when the positions of the guide pin 3 and the guide hole 4 are shifted, the tapered portion 3a is guided by the guide hole 4 and is inserted into the guide hole 4, and when the tapered portion 3a is completely inserted into the guide hole 4. Thus, the alignment between the movable connector 5 and the fixed connector 6 is completed. When the movable connector 5 is further moved in the direction of the fixed connector 6, the movable female pin 1 starts to contact the fixed male pin 2. At this time, since the positioning of the movable-side and fixed-side connectors 5 and 6 has been completed, the movable-side female pin 1 is fitted and mounted on the fixed-side male pin 2 while maintaining an extremely good contact state, and the superconducting coil 24 is mounted. Is supplied with an exciting current.

Next, the superconducting coil 24 is energized to the rated current, and the superconducting coil 24 is operated in the permanent current mode. Then, the movable mechanism 5 is moved by the driving mechanism in a direction to separate the movable connector 5 from the fixed connector 6, and The female pin 1 is separated from the fixed male pin 2 and the supply of the exciting current to the superconducting coil 24 is stopped.

Since the fixed connector 6 is supported from the helium tank 23 on the low temperature side, there is no thermal path for directly connecting the normal temperature side and the low temperature side when the detachable power lead 30 is detached. Heat penetration can be almost eliminated.

As described above, according to the second embodiment, the sum of the distance (L ₃ ) between the tip of the guide pin 3 and the fixed connector 6 and the length (L ₄ ) of the tapered portion 3a ( L ₁ ) ≦
Distance between the movable female pin 1 and the fixed male pin 2 (L
₂ ), a movable connector 5 is provided with a guide pin 3 having a movable female pin 1 and a tapered portion 3a, and a fixed connector 6 is provided with a detachable power lead provided with a fixed male pin 2 and a guide hole 4. Since the excitation current is supplied to the superconducting coil, the current flowing per pin can be increased, a large current can be supplied, and the thermal path between the normal temperature part and the low temperature part at the time of detachment is almost Can be completely shut off,
There is an effect that a superconducting magnet device that can suppress the heat intrusion from the room temperature portion to be extremely small can be obtained.

In each of the above embodiments, the movable pin 1 is used as the second pin and the fixed pin 2 is used as the first pin. However, the male pin is used as the second pin. Alternatively, a female pin may be used as the first pin.

In each of the above embodiments, the guide pin 3 is provided on the movable connector 5 and the guide hole 4 is provided on the fixed connector 6. However, the guide pin 3 is provided on the fixed connector 6. The guide hole 4 may be provided in the movable connector 5.

Further, in each of the above-described embodiments, one guide pin 3 is provided and the positions of the movable side and fixed side connectors 5 and 6 are adjusted. However, a plurality of guide pins are provided. Movable and fixed connectors 5, 6
Can be performed more reliably.

In each of the above embodiments, the movable side female pin 1, the fixed side male pin 2, and the guide pin 3 are connected to the movable side and fixed side connectors 5, 6 by nuts 7a, 7b, 7c.
Although it is described that the pins are fixed to the connector, any pin can be used as long as these pins can be fixed to the connector.

[0031]

Since the present invention is configured as described above, it has the following effects.

According to the first aspect of the present invention, a guide pin having a tapered portion at the distal end is provided on one of the fixed portion and the movable portion, and the guide hole for engaging the guide pin by the movement of the movable portion is provided on the fixed portion and the movable portion. At the other end of the movable portion, the sum L ₁ of the distance between the tip of the guide pin and the entrance of the guide hole and the length of the tapered portion is defined as the distance L ₂ between the first pin and the second pin. On the other hand, since L ₁ ≦ L ₂ , the positioning of the movable portion and the fixed portion can be reliably performed by engagement of the guide pin and the guide hole by the movement of the movable portion, and regardless of the number of pins,
A reliable connection with low contact resistance can be achieved, a current value per pin can be increased, and a highly reliable detachable power lead can be obtained without an increase in contact resistance due to detachment and pin breakage.

According to the second aspect of the present invention, the power lead for supplying the exciting current to the superconducting coil is provided by the first power lead.
A fixed portion on which the first pin is disposed, a movable portion disposed opposite to the fixed portion, a second pin provided on the movable portion, the second pin being fitted to and disengaged from the first pin when the movable portion moves. A guide pin provided at one of the movable portions and having a tapered portion at the distal end, and a guide hole provided at the other of the fixed portion and the movable portion and engaged with the guide pin by the movement of the movable portion. Power L ₁ ≦ L _{2 where} the sum L ₁ of the distance between the portion and the entrance of the guide hole and the length of the tapered portion is L ₁ ≦ L ₂ with respect to the distance L ₂ between the first pin and the second pin. Because it is a lead, the current value per pin can be increased,
A superconducting magnet device that can supply a large current, can almost completely shut off the thermal path between the normal temperature portion and the low temperature portion at the time of desorption, and can suppress heat intrusion from the normal temperature portion to an extremely small level.

[Brief description of the drawings]

FIG. 1 is a sectional view of a detachable portion of a detachable power lead according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a superconducting magnet device according to a second embodiment of the present invention.

FIG. 3 is a sectional view of a connecting portion showing an example of a conventional detachable power lead.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 movable side female pin (second pin) 2 fixed side male pin (first pin) 3 guide pin 3a tapered portion 4 guide hole 5 movable side connector (movable portion) 6 fixed side connector (fixed portion) 20 vacuum chamber 21st 1 Radiant heat shield 22 Second radiant heat shield 23 Helium tank 24 Superconducting coil 24 Detachable power lead

Claims (2)

(57) [Claims] A fixed portion provided with a first pin and a movable portion provided with a movable portion provided with a second pin fitted to the first pin, wherein the detachable portion is provided. In a detachable power lead that opens and closes an electrical connection by fitting and disengaging the first and second pins by moving a movable portion, a guide pin having a tapered portion at a distal end portion is provided on one of the fixed portion and the movable portion. A guide hole that engages with the guide pin by the movement of the movable portion, is provided in the other of the fixed portion and the movable portion, and a distance between a tip end of the guide pin and an entrance of the guide hole and the taper portion are provided. of the sum L ₁ of the length, with respect to the distance L ₂ between the first pin and the second pin,
A detachable power lead, wherein L ₁ ≦ L ₂ . 2. A helium tank, a radiant heat shield surrounding the helium tank, a vacuum tank surrounding the radiant heat shield, a superconducting coil housed in the helium tank, In a superconducting magnet device having a power lead for supplying an exciting current to a superconducting coil, the power lead includes a fixed portion provided with a first pin, and a movable portion provided opposed to the fixed portion. A second pin that is provided on the movable portion and that fits into and disengages from the first pin by the movement of the movable portion; a guide pin that is provided on one of the fixed portion and the movable portion and has a tapered portion at a distal end portion; A guide hole provided on the other of the fixed portion and the movable portion, the guide portion being engaged with the guide pin by the movement of the movable portion; and a distance between a tip end of the guide pin and an entrance of the guide hole, and The sum L ₁ and the length of the tapered portion, the relative distance L ₂ between the first pin and the second pin, a superconducting magnet, characterized in that the detachable power lead to L ₁ ≦ L ₂ apparatus.