JP2955670B2 - Actuator controlled by temperature change - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an actuator controlled by a temperature change, a flow control device using the actuator, and a Joule-Thomson type cooling device.

[0002]

2. Description of the Related Art In a Joule-Thomson type cooling apparatus, a refrigerant gas is jetted from a fine hole into an expansion space, and cold is generated by adiabatic expansion of the refrigerant gas. The Joule-Thomson type cooling device is provided with a flow rate control mechanism that adjusts the amount of refrigerant gas jetted according to the temperature of the object to be cooled, in order to keep the cooling temperature constant and suppress wasteful consumption of the refrigerant gas. .

[0003] A conventional flow rate control mechanism controls the flow rate of a refrigerant gas by driving an actuator by utilizing a pressure change caused by a temperature change of a high-pressure gas sealed in an airtight space, for example. Further, there have been proposed ones that perform flow rate control using a bimetal and those that perform flow rate control by utilizing thermal shrinkage of a metal at a low temperature.

[0004]

The flow rate control mechanism utilizing the pressure fluctuation due to the temperature change of the high-pressure gas is difficult to reduce the cost because of the complicated structure and the necessity of the high-pressure gas sealing step. . Further, a device using a bimetal or a device utilizing heat shrinkage of a metal at a low temperature has not yet been put into practical use due to the complexity of a driving mechanism and the like.

An object of the present invention is to provide an actuator having a novel structure controlled by a change in temperature.
It is another object of the present invention to provide a flow rate control device that can control a gas flow rate by a change in temperature by using an actuator having a novel structure.

It is another object of the present invention to provide a Joule-Thomson type cooling device incorporating a flow control device using an actuator having a novel structure.

[0007]

According to one aspect of the present invention, a support member having physical support force, a movable member movably attached to the support member within a movable range, A first magnetic member relatively fixed to the movable member; and a first magnetic member fixed relatively to the movable member, facing the first magnetic member with a gap interposed therebetween, and the width of the gap is equal to the width of the movable member. A second magnetic member that changes with movement, and a magnetomotive force generating means that generates a magnetic force between the first magnetic member and the second magnetic member in a direction that changes the thickness of the gap. And wherein one of the first and second magnetic members is formed of a magnetic material whose magnetic permeability changes with temperature.

[0008] When the magnetic permeability of the magnetic material changes due to a temperature change, the magnitude of the magnetic force between the first magnetic member and the second magnetic member changes. Due to the change in the magnetic force, the thickness of the gap changes, and the movable member moves.

According to another aspect of the present invention, a gas flow path having an inflow end through which gas flows in and an outflow end through which the gas flows out, and a flow path resistance of the gas flow path moving within a movable range. Movable member, an elastic member for elastically supporting the movable member, a first magnetic member fixed relative to the gas flow path, and a fixed member relative to the movable member. A second magnetic member opposed to the first magnetic member with a gap therebetween, and the thickness of the gap changes with the movement of the movable piece; A magnetomotive force generating means for generating a magnetic force in a direction to change the thickness of the gap between the magnetic member and one of the first and second magnetic members; Provided is a flow control device formed of a magnetic material that changes magnetic permeability.

When the movable piece moves due to a temperature change, the flow path resistance fluctuates. Therefore, the gas flow rate can be controlled by the temperature change. According to another aspect of the present invention, there is provided a flow control device in which the one magnetic member is made of a magnetic material that exhibits paramagnetism at a Curie temperature or higher and ferromagnetism at a Curie temperature or lower.

[0011] The magnetic permeability of one magnetic member changes abruptly from the Curie temperature. Therefore, there is a large difference in magnetic force between the first magnetic member and the second magnetic member depending on the Curie temperature. The movable piece can be moved by the difference in magnetic force.

According to another aspect of the present invention, the flow control device, an expansion space in which gas ejected from an outflow end of the gas flow path expands to generate cold, and an expansion space in which the gas blows out from the inflow end of the gas flow path. A Joule-Thomson-type cooling device having an introduction passage for supplying gas into a gas passage and a discharge passage for discharging gas in the expansion space from the expansion space while exchanging heat with the gas in the introduction passage is provided. Is done.

When the temperature of the gas in the expansion space fluctuates, the temperature of the magnetic member of the flow control device changes due to heat conduction.
The gas flow rate changes according to the temperature change of the magnetic member, and the cooling capacity changes. If the gas flow rate is controlled such that the cooling capacity increases when the cooling temperature increases and the cooling capacity decreases when the cooling temperature decreases, the cooling temperature can be kept almost constant.

[0014]

FIG. 1 is a sectional view of a flow control device according to a first embodiment of the present invention. A gas flow path 2 is formed inside a plate-shaped support member 1. The gas flow path 2 includes a fine hole 2c opening on the upper surface of the support member 1 in the drawing, a tapered portion 2b communicating with the fine hole 2c at a vertex of the tapered inner peripheral surface, and a circular pipe continuous with the tapered surface of the tapered portion 2b. It is configured to include the portion 2a. The large diameter side of the tapered portion 2b is formed in a cylindrical shape, and the cylindrical portion is opened on the lower surface of the support member 1 in the figure. The tapered tip of the movable piece 3 is inserted into the tapered portion 2b from the lower surface opening of the support member 1. When the movable piece 3 is inserted deeply into the tapered portion 2b, the tapered surface at the tip thereof comes into close contact with the tapered surface of the tapered portion 2b.

A permanent magnet 5 extending from the opening of the tapered portion 2b toward both sides is attached to the lower surface of the support member 1. The permanent magnets 5 on both sides of the opening are annular portions surrounding the opening of the tapered portion 2b (not shown in the figure).
To form a single permanent magnet. For example, the left end in the figure is the S pole, and the right end is the N pole. Permanent magnet 5
Is composed of, for example, a ferrite magnet, an alnico magnet, a samarium-cobalt magnet, a neodymium magnet, and the like.

A magnetic material 4 made of a ferromagnetic material such as iron is fixed to the lower end of the movable piece 3 almost in parallel with the permanent magnet 5. A magnetic member 6 </ b> A made of dysprosium is arranged between the S-pole side end of the permanent magnet 5 and the corresponding end of the magnetic material 4. The magnetic member 6A is fixed to the permanent magnet 5,
A gap 9A having a thickness T is defined between the magnetic member 4 and the magnetic member 4.

A magnetic material 6B made of dysprosium is similarly fixed to the end of the permanent magnet 5 on the N pole side, and a gap 9A having the same thickness as the gap 9A is provided between the magnetic member 6B and the magnetic member 4.
B is defined. Thus, the magnetic member 6B,
A magnetic circuit 8 including the gap 9B, the magnetic member 4, the gap 9A, the magnetic member 6A, and the permanent magnet 5 is formed.

The movable piece 3 and the magnetic member 4 are guided vertically by a linear guide mechanism (not shown). A stopper 10 is disposed below the magnetic member 4 in the drawing, and limits the movable range of the movable piece 3 and the magnetic member 4. The magnetic member 4 is urged by a coil spring 7 in a direction away from the permanent magnet 5. The coil spring 7 is preferably formed of a non-magnetic material. The movable piece 3 stops at a position where the attractive force between the permanent magnet 5 and the magnetic material 4 and the elastic force of the coil spring 7 are balanced.

Since the Curie temperature of dysprosium is 89K, it exhibits paramagnetism at a temperature of 89K or higher,
The following temperatures show ferromagnetism. That is, the magnetic permeability changes abruptly at 89K. Permanent magnet 5 and magnetic member 4
Is relatively weak when the temperature of the magnetic members 6A and 6B is 89K or more, and becomes strong when the temperature is 89K or less.

When the temperature of the magnetic members 6A and 6B is 89 K or more, the attractive force between the permanent magnet 5 and the magnetic member 4 is weak, so that the amount of insertion of the movable piece 3 into the tapered portion 2b is small.
Accordingly, the gas flowing from the right end of the circular pipe portion 2a of the gas flow path 2 in the figure is ejected to the upper side of the support member 1 through the tapered portion 2b and the fine holes 2c.

When the temperature of the magnetic members 6A and 6B becomes 89K or less, the attractive force between the permanent magnet 5 and the magnetic member 4 becomes strong, so that the movable piece 3 is inserted deeply into the tapered portion 2b.
Therefore, the flow path resistance of the tapered portion 2b increases, and the gas flow rate decreases. When the tapered surface at the tip of the movable piece 3 comes into close contact with the tapered surface of the tapered portion 2b, gas hardly flows.

As described above, by changing the temperature of the magnetic members 6A and 6B to change the insertion amount of the movable piece 3,
The gas flow can be controlled. In FIG. 1, the permanent magnets 5 and the magnetic materials 6A and 6 whose magnetic permeability changes with temperature are shown.
Although the case where B is fixed to the gas flow path 2 and the ferromagnetic material 4 is fixed to the movable piece 3 has been described, the combination of the member fixed to the gas flow path and the member fixed to the movable piece may be changed. .
For example, a ferromagnetic material may be used instead of the permanent magnet 5, and a permanent magnet may be used instead of the ferromagnetic material 4. Further, a ferromagnetic material may be used instead of the magnetic members 6A and 6B, and a magnetic material whose magnetic permeability changes depending on temperature may be used instead of the ferromagnetic material 4.

In FIG. 1, a ferromagnetic material, a permanent magnet,
Although the case where three types of magnetic members whose magnetic permeability changes according to temperature is used has been described, two types of materials, a permanent magnet and a magnetic material whose magnetic permeability changes according to temperature, may be used. In this case, one material is fixed to the gas flow path 2 side, and the other magnetic member is fixed to the movable piece 3 side.

FIG. 2 is a sectional view of a flow control device according to a second embodiment of the present invention. The support member 1 and the gas passage 2 formed therein have the same configuration as that shown in FIG.

The tapered tip of the movable piece 13 is inserted into the tapered portion 2b. A permanent magnet 14 is fixed to the rear end of the movable piece. For example, the left end of the figure of the permanent magnet 14 is S
Pole and the right end is the north pole.

Below the figure of the permanent magnet 14, the permanent magnet 14
The permanent magnets 15 are arranged substantially in parallel with each other and such that the N poles and the S poles face each other. The permanent magnet 15
It is attached and fixed to the support member 1.

A magnetic member 16A made of dysprosium is arranged between the S pole of the permanent magnet 14 and the S pole of the permanent magnet 15. The magnetic member 16A is fixed to the permanent magnet 15 and defines a gap 19A having a thickness T between itself and the permanent magnet 14. Similarly, a magnetic member 16B made of dysprosium is fixed to the N pole side of the permanent magnet 15, and a gap 19B having the same thickness as the gap 19A is defined.

The movable piece 13 and the permanent magnet 14 are guided vertically by a linear guide mechanism (not shown), and the lowermost point at which the permanent magnet 14 contacts the magnetic members 16A and 16B and the tip of the movable piece 13 are moved. The parallel movement is possible between the uppermost point that contacts the tapered surface of the tapered portion 2b.

The permanent magnet 14 is urged downward by a coil spring 17 in the figure. The movable piece 13 stops at a position where the repulsive force between the permanent magnets 14 and 15 and the elastic force of the coil spring 17 are balanced. Magnetic materials 16A and 1
As the magnetic permeability of 6B changes with temperature, the repulsion between permanent magnets 14 and 15 changes. For this reason, the insertion amount of the movable piece 13 into the tapered portion 2b changes due to the temperature change, and the gas flow rate can be controlled.

In the case of the flow control device shown in FIG. 1, the attractive force between the permanent magnets decreases in inverse proportion to the square of the thickness T of the gaps 9A and 9B, and the elastic force of the coil spring 7 is proportional to the thickness T. And decrease. That is, when the thickness T increases, both the attractive force and the elastic force decrease, and when the thickness T decreases, both the attractive force and the elastic force increase. Since the directions of increase and decrease of the thickness T of the attractive force and the elastic force are the same, it is relatively difficult to stably stop the movable piece 3 at the middle point of the movable range.

In the case of the flow control device shown in FIG. 2, the repulsive force between the permanent magnets decreases in inverse proportion to the square of the thickness T of the gaps 19A and 19B, and the elastic force of the coil spring 7 is proportional to the thickness T. And increase. Since the directions of increase and decrease of the thickness T of the repulsive force and the elastic force are opposite, the movable piece 13 can be stably stopped at the middle point of the movable range.

As described above, the flow control device shown in FIG. 1 is suitable for controlling the opening and closing of the gas flow path, and the flow control device shown in FIG. 2 is suitable for fine adjustment of the gas flow. FIGS. 1 and 2 show the case where the movable piece is driven by using the change in the magnetic permeability of the ferromagnetic material. However, the pinning effect of the superconducting material may be used.

When the pinning effect is used, for example, a member made of a superconductive material is used instead of the permanent magnet 15 and the magnetic members 16A and 16B of FIG. When the temperature of the superconducting member becomes low, the superconducting member interacts with the permanent magnet 14 by a pinning effect. If the temperature is constant, the relative position between the superconducting member and the permanent magnet 14 is fixed by the pinning effect.

When the temperature decreases, the repulsive force due to the pinning effect increases, and the movable piece 13 is driven upward in FIG. For this reason, the gas flow rate decreases. As described above, the gas flow rate can be controlled using the temperature dependency of the pinning effect.

FIG. 3A is a sectional view of a flow control device according to a third embodiment of the present invention. Through hole 3 in support member 1
1 is formed, and a gas flow path 2 formed inside the support member 1 is opened on a side surface of the through hole 31. A permanent magnet 5 is attached to the lower surface of the support member 1 and extends from the opening on the lower surface side of the through hole 31 toward both sides. The permanent magnets 5 on both sides of the opening are connected to each other by an annular member (not shown in the figure) surrounding the opening of the through hole 31 to constitute one permanent magnet. For example, the left end of the figure is the south pole,
The right end is the north pole.

The pivot shaft 33 is inserted into the through hole 31, and the flanges 3 provided at the upper end and the intermediate portion of the side surface, respectively.
8A and 38B constrain the axial position. The rotating shaft 33 is formed with a gas flow path 32 having both upper and side surfaces open at both ends.

The rotating shaft 33 is rotatable around its central axis. At a certain position, the opening on the side surface of the gas flow path 32 faces the opening of the gas flow path 2 and the two gas flow Roads communicate. At other positions, the openings do not face each other, and the two gas flow paths do not communicate with each other.

A rod 34 made of a ferromagnetic material such as iron is fixed to the lower end of the rotating shaft 33. When the gas flow path 32 and the gas flow path 2 communicate with each other, the rod-shaped member 34
It is almost parallel to 5. A magnetic member 36A made of dysprosium is arranged between the S-pole side end of the permanent magnet 35 and the corresponding end of the bar-shaped member 34. Magnetic member 36A
Is fixed to a permanent magnet 35, and a gap 39A is defined between the rod 35 and the permanent magnet 35.

A magnetic member 36B is similarly fixed to the end of the permanent magnet 35 on the N pole side, and a gap 39B is defined between the permanent magnet 35 and the rod-shaped member 34. A coil spring 37 is arranged coaxially with the rotation shaft 33, one end of which is fixed to the permanent magnet 35, and the other end of which is fixed to the bar-shaped member 34. The coil spring 37
A torque in one direction around the central axis of the rotating shaft 33 is applied to the rod-shaped member 34 and the rotating shaft 33.

FIG. 3B is a plan view of the flow control device of FIG. 3A at a temperature higher than the Curie temperature of dysprosium. The rod member 34 is urged by the coil spring 37 in the clockwise direction in FIG. The rod member 34 rotates clockwise by the elastic force of the coil spring 37 and stops at a position where one end thereof contacts the stopper 50. At this time, the gas flow path 32 communicates with the gas flow path 2, and gas is ejected from the gas flow path 2 via the gas flow path 32.

FIG. 3C is a plan view of the flow control device at a temperature lower than the Curie temperature. Since the magnetic members 36A and 36B shown in FIG. 3A show ferromagnetism, the attractive force between both ends of the rod member 34 and the magnetic members 36A and 36B increases. When the torque due to the attraction force becomes larger than the torque due to the elastic force of the coil spring 37,
The rod 34 rotates counterclockwise.

The rod-shaped member 34 stops at a position where the right end side surface contacts the stopper 51. At this time, the gas flow path 3
2 does not communicate with the gas flow path 2, so that gas ejection stops. As described above, the gas flow can be controlled by controlling the torque by changing the magnetic force and rotating the rotating shaft.

FIGS. 1 to 3 show the case where the gas flow rate is controlled by changing the flow path resistance by moving the movable piece. However, the present invention can be used for other purposes. For example,
It can be used as a general-purpose temperature control type actuator such as an electric switch that opens and closes electrical contacts by moving a movable piece, an optical switch that blocks an optical path, an automatic opening and closing device that opens and closes a window, and the like.

FIG. 4 is a sectional view of a Joule-Thomson type cooling device incorporating the flow control device shown in FIG. The Joule-Thomson type cooling device is configured to include a refrigerant gas introduction pipe 40, a flow control device 20, a cylindrical member 43, and a Dewar bottle 60.

Fins 4 for efficiently exchanging heat inside and outside the refrigerant gas introduction pipe are provided on the outer peripheral surface of the refrigerant gas introduction pipe 40.
4 is attached. The refrigerant gas introduction pipe 40 is spirally wound around the outer peripheral surface of the cylindrical member 43 at such a pitch that the fins 44 substantially contact each other. Refrigerant gas inlet pipe 4
0 is made of, for example, a copper-nickel alloy,
Is formed, for example, of copper.

A string 45 is wound so as to fill the gap between the fins 44 adjacent in the spiral axis direction. String 4
5, the refrigerant gas introduction pipe 40 can be fixed stably. One end of the cylindrical member 43 is provided with a flow control device 20.
The other end is not shown in the figure, but is, for example, an open end. The flow control device 20 has substantially the same configuration as that shown in FIG. 1, and corresponding portions are denoted by the same reference numerals.

FIG. 1 shows a case where the magnetic members 6A and 6B are arranged only between the permanent magnet 5 and the magnetic member 4, but in the flow control device 20 shown in FIG. And 6B penetrate the support member 1 and a part of the surface is exposed outside the cylindrical member 43. The stopper 10 is fixed to the inner peripheral surface of the cylindrical member 43. Other configurations are the same as those of the flow control device shown in FIG.

One end of the refrigerant gas introduction pipe 40 is connected to the circular pipe portion 2 a (FIG. 1) of the gas flow path 2 of the flow control device 20. Note that the circular tube portion 2a does not appear in the cross-sectional view shown in FIG. Refrigerant gas is supplied from the refrigerant gas introduction pipe 40 into the circular pipe portion of the gas flow path 2 and is ejected to the outside through the tapered portion and the fine holes.

[0049] The refrigerant gas introduction pipe 4 constructed as described above.
0, the portion including the flow control device 20 and the cylindrical member 43 is inserted into the double-walled dewar 60, and the flow control device 20
Space 6 between the supporting member 1 and the inner wall of the Dewar bottle 60
1 is defined. The Dewar 60 is made of, for example, glass. The inner diameter of the inner wall of the Dewar bottle 60 is set to a size such that the inner peripheral surface thereof substantially contacts the fin 44.

A part of the outer wall of the Dewar bottle 60 at the upper end is formed of an infrared transmitting member 63. The infrared transmitting member 63 is formed of, for example, germanium, sapphire, or the like.

The object to be cooled 70 is attached to the inner wall of the Dewar 60 at a position facing the infrared transmitting member 63. The inner cavity 62 of the double wall of the Dewar bottle 60 is vacuum-sealed after the object 70 to be cooled is attached. Cooled object 7
Reference numeral 0 denotes an infrared detecting element using, for example, a Schottky junction between silicon and platinum cobalt.

Next, the operation of the Joule-Thomson type cooling device will be described. A high-pressure refrigerant gas is supplied from the lower end of the refrigerant gas introduction pipe 40 in the drawing. The refrigerant gas is, for example, nitrogen, argon, air, or the like. The refrigerant gas is introduced into the gas flow path 2 through the refrigerant gas introduction pipe 40, and is ejected from the fine holes into the expansion space 61. At this time, cold is generated by the Joule-Thomson effect, and the object to be cooled 70 is cooled.

The low-temperature refrigerant gas in the expansion space 61 is discharged to the outside through the space between the cylindrical member 43 and the inner wall of the dewar 60. At this time, the low-temperature refrigerant gas cools the refrigerant gas introduction pipe 40. Since the fins 44 are provided in the refrigerant gas introduction pipe 40, heat can be efficiently exchanged between the gas flowing inside the refrigerant gas introduction pipe 40 and the gas flowing outside. Further, the string 45 obstructs the flow of the refrigerant gas to generate turbulence, so that the heat exchange efficiency is improved. Since the refrigerant gas flowing in the refrigerant gas introduction pipe 40 exchanges heat with the discharged refrigerant gas and is cooled, the cooling efficiency can be improved.

When the temperature in the expansion space 61 decreases, the temperatures of the magnetic members 6A and 6B also decrease. When the temperature of the magnetic members 6A and 6B becomes equal to or lower than the Curie temperature of dysprosium, the movable piece 3 is inserted deeply into the tapered portion of the gas flow path 2, and the amount of refrigerant gas jetted decreases or jetting stops.

When the ejection amount of the refrigerant gas decreases or the ejection stops, the temperature in the expansion space 61 increases. When the temperature of the magnetic members 6A and 6B becomes equal to or higher than the Curie temperature of dysprosium, the ejection amount of the refrigerant gas increases again.
The temperature in the expansion space 61 decreases. In this way, the temperature in the expansion space 61 can be adjusted, and the refrigerant gas can be saved.

The magnetic member 6 made of dysprosium
A and 6B may be brought into contact with the vicinity of the end of the cylindrical member 43 on the expansion space 61 side. In this case, when the cooled refrigerant gas in the expansion space 61 is discharged through the space between the cylindrical member 43 and the inner wall of the Duer bottle 60, the magnetic member 6
Cool A and 6B.

As the flow control device 20, the flow control device shown in FIG. 2 or FIG. 3 may be used. When the flow control device shown in FIG. 2 is used, a part of the surfaces of the magnetic members 16A and 16B is exposed in the expansion space 61,
Alternatively, it is preferable to contact the vicinity of the end of the cylindrical member 43 on the expansion space 61 side.

In the above embodiment, the case where dysprosium is used as the magnetic material for changing the magnetic permeability according to the temperature change has been described, but other materials may be used. For example, erbium (Er) having a Curie temperature of 20K, gadolinium (Gd) having a Curie temperature of 293K, terbium (Tb) having a Curie temperature of 219K, other selenium (Ce), praseodymium (Pr), and neodymium (N
d), a rare earth element having an atomic number of 58 to 69, such as promesium (Pm), samarium (Sm), europium (Eu), holmium (Ho), and thulium (Tm), or an alloy thereof may be used. Alternatively, an oxide magnetic material such as europium oxide (EuO) having a Curie temperature of 77K and europium sulfide (EuS) having a Curie temperature of 18K may be used.

The present invention has been described in connection with the preferred embodiments.
The present invention is not limited to these. For example, it will be apparent to those skilled in the art that various modifications, improvements, combinations, and the like can be made.

[0060]

As described above, according to the present invention,
A temperature-controlled actuator having a simple structure can be obtained.
Using this actuator, a flow control device having a simple structure and a Joule-Thomson cooling device can be manufactured.

[Brief description of the drawings]

FIG. 1 is a sectional view of a flow control device according to a first embodiment of the present invention.

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

FIG. 3 is a sectional view of a flow control device according to a third embodiment of the present invention.

FIG. 4 is a sectional view of a Joule-Thomson type cooling device incorporating the flow control device according to the first embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Support member 2 Gas flow path 2a Micropore 2b Taper part 2c Circular tube part 3, 13 Movable piece 4, 6A, 6B, 16A, 16B Magnetic member 5, 14, 15 Permanent magnet 7, 17 Coil spring 8 Magnetic circuit 9A, 9B , 19A, 19B Gap 10 Stopper 20 Flow control device 31 Through hole 32 Gas flow path 33 Rotating shaft 34 Bar-shaped member 35 Permanent magnet 36A, 36B Magnetic member 37 Coil spring 38A, 38B Flange 39A, 39B Gap 50, 51 Stopper 40 Refrigerant Gas introduction tube 43 Cylindrical member 44 Fin 45 String 60 Dewar bottle 61 Expansion space 62 Internal cavity 63 Infrared transmitting member 70 Cooling object

Claims (13)

(57) [Claims] A support member having a physical support force; a movable member movably attached to the support member within a movable range; and a first magnetic member fixed relative to the support member. A second magnetic member fixed relative to the movable member and opposed to the first magnetic member with a gap interposed therebetween, wherein the width of the gap changes with the movement of the movable member; And a magnetomotive force generating means for generating a magnetic force in a direction that changes the thickness of the gap between the first magnetic member and the second magnetic member, wherein the first and second magnetic members are provided. An actuator in which one of the magnetic members is formed of a magnetic material whose magnetic permeability changes with temperature. 2. The actuator according to claim 1, wherein the movable member and the second magnetic member are formed as an integral member. 3. The device according to claim 1, wherein the other of the first and second magnetic members also serves as the magnetomotive force generating means.
An actuator according to claim 1. 4. The actuator according to claim 1, wherein said magnetomotive force generating means is a permanent magnet. 5. A gas flow path having an inflow end through which gas flows in and an outflow end through which gas flows out, a movable piece that moves within a movable range and varies the flow resistance of the gas flow path, An elastic member for elastically supporting the movable piece; a first magnetic member fixed relatively to the gas flow path; and a first magnetic member fixed relatively to the movable piece. A second magnetic member opposed to the member with a gap therebetween, and the thickness of the gap changes with the movement of the movable piece; and between the first magnetic member and the second magnetic member, A magnetomotive force generating means for generating a magnetic force in a direction to change the thickness of the gap, wherein one of the first and second magnetic members is
A flow control device made of a magnetic material whose magnetic permeability changes with temperature. 6. The flow control device according to claim 5, wherein the one magnetic member is made of a magnetic material exhibiting paramagnetism above the Curie temperature and ferromagnetic below the Curie temperature. 7. The flow control device according to claim 5, wherein the one magnetic member is the first magnetic member, and the second magnetic member is formed of a ferromagnetic material. 8. The magnetomotive force generating means is a permanent magnet fixed to the first magnetic member, the second magnetic member is another permanent magnet, and the permanent magnet and the other permanent magnet are ,
The flow rate control device according to any one of claims 5 to 7, wherein a magnetic force is generated between the first magnetic member and the second magnetic member so as to generate a magnetic force in a direction repelling each other. 9. The gas flow path includes a tapered portion having a tapered inner peripheral surface, and a part of the movable piece is inserted into the tapered part, and the insertion amount is changed to change the gas flow path. 9. The flow control device according to claim 5, wherein the flow passage resistance is changed. 10. The flow control device according to claim 5, wherein a gas ejected from an outflow end of the gas flow path expands to generate cold, and an inflow of the gas flow path. A Joule-Thomson type cooling system having an introduction path for supplying gas from the end into the gas flow path, and a discharge path for discharging the gas in the expansion space from the expansion space while exchanging heat with the gas in the introduction path. apparatus. 11. The third magnetic member according to claim 10, wherein a partial surface of the third magnetic member is in contact with the expansion space, and heat is directly exchanged between the third magnetic member and gas in the expansion space. Joule Thomson type cooling device. 12. The method according to claim 10, wherein a partial surface of the third magnetic member is in contact with an outer peripheral surface of the discharge path, and heat is directly exchanged between the third magnetic member and the discharge path. Joule Thomson type cooling device. 13. A support member having physical support force, a movable member movably attached to the support member within a movable range, and a first member fixed relative to the support member. A second member fixed relative to the movable member, opposed to the first member with a gap therebetween, and the width of the gap changes with the movement of the movable member; A magnetomotive force generating means for generating a magnetic force in a direction to change the thickness of the gap, between the first magnetic member and the second magnetic member; One is an actuator made of superconducting material.