JPH0739893B2 - refrigerator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] This invention relates to, for example, an infrared detection element at an extremely low temperature (eg 77K).
Before and after) relates to cooling Stirling refrigerator.

[Prior Art] FIG. 6 shows a configuration example of a conventional Stirling refrigerator. The Stirling refrigerator is roughly divided into a compressor (1), a cold finger (2), and a connecting pipe (3) connecting them. The compressor (1) has a first cylinder (4a) and a second cylinder (4a).
Cylinder (4b), a first piston (5a) and a second piston (5b). First piston (5a) and second
Piston (5b) is attached to one end of each support spring (6a) (6b) extending from the inner wall of the housing (10), and reciprocates inside the first cylinder (4a) and the second cylinder (4b). It has a structure.

A first moving coil (8a) and a second moving coil (8b) are connected to the first piston (5a) and the second piston (5b). The first moving coil (8a) and the second moving coil (8b) are each made of a non-magnetic material and are lightweight first.
A conductor (9) is attached to the sleeve (7a) and the second sleeve (7b).
It is formed by winding a) and (9b). The moving coils (8a) and (8b) are provided with a first lead wire (11a) and a second lead wire (1a) extending to the outside through the wall of the housing (10).
1b) and these lead wires (11a) (11b)
Is the first electrical contact (12a) on the outside of the housing (10),
And a second electrical contact (12b). Housing (10)
Inside, permanent magnets (13a) (13b) and a yoke (14) are provided, and these constitute a magnetic circuit (15).

The movable coils (8a) and (8b) are inside the first gap (16a) and the second gap (16b) provided in the magnetic circuit (15) including the permanent magnets (13a) (13b) and the yoke (14). At the piston (5
The structure is such that it can reciprocate in the axial direction of a) and (5b). Moving coil (8a) (8b) in the gap (16a) (16b)
There are permanent magnets in the radial direction across the direction of motion of.

The internal space defined by the cylinders (4a) (4b) and the pistons (5a) (5b) is called a compression chamber (17). The compression chamber (17) is filled with a high-pressure working gas such as helium. The working gas in the compression chamber (17) flows between the cylinder (4a) and the piston (5a), and between the cylinder (4b) and the piston (5).
so that it does not pass through the gap b), the gap between the cylinder (4a) and the piston (5a), and the cylinder (4b) and the piston (5a).
The gap in b) is made as narrow as possible. The above is the configuration of the compressor (1).

On the other hand, the cold finger (2) has a cylindrical low temperature cylinder (18) and a displacer (20) which is engaged by a resonance spring (19) and slidably reciprocates in the low temperature cylinder (18). There is. The space inside the low-temperature cylinder (18) is divided into two by the displacer (20). The space above the displacer (20) is called the low-temperature chamber (21) and the space below it is called the high-temperature chamber (22).

A regenerator (23) and a gas passage hole (24) are provided inside the displacer (20), and the low temperature chamber (21) and the high temperature chamber (22) are provided through the regenerator (23) and the gas passage hole (24). They are in communication,
Inside the regenerator (23), for example, livestock cooling material (25) such as copper wire mesh.
Is filled. The gap between the displacer (20) and the low temperature cylinder is made as narrow as possible so that the working gas does not pass through the gap between the low temperature cylinder (18) and the displacer (20). Each chamber of the cold finger (2) is filled with a high-pressure working gas such as helium as in the compression chamber (17).

The compression chamber (17) of the compressor (1) and the high temperature chamber (22) of the cold finger (2) communicate with each other via a connecting pipe (3). Further, the compression chamber (17), the space inside the connecting pipe (3), the low temperature chamber (21), the high temperature chamber (22), the regenerator (23) and the gas passage hole (24) communicate with each other. The entire chamber is collectively called the working chamber (26).

The operation of the conventional refrigerator configured as described above will be described.

When an alternating current is applied to the moving coils (8a) (8b) through the electrical contacts (12a) (12b) and the lead wires (11a) (11b), the moving coils (8a) (8b) have gaps (16a) respectively. (16
The Lorentz force acts in the axial direction due to the interaction with the permanent magnetic field in b). As a result, the assembly consisting of the pistons (5a) (5b) and the moving coils (8a) (8b) becomes a piston (5a).
Move left and right in the axial direction of (5b).

Now, the characteristics of the first movable coil (8a) and the second movable coil (8b) are made the same, and the first gap (16a) and the second gap (1
When the first moving coil (8a) and the second moving coil (8b) are oscillated with the same amplitude in opposite directions under the condition that the magnetic fields in 6b) have the same strength, Pistons (5a) (5b) are in opposite directions to cylinders (4a) (4
It reciprocates in the inside of b) and moves from the compression chamber (17) to the low temperature chamber (2
A sinusoidal wave is applied to the gas pressure in the working chamber (27) up to 1).

The displacer (20) including the regenerator (23) has a piston (5a) due to a change in the gas flow rate passing through the displacer (20) and the regenerator (23) due to the sinusoidal pressure wave.
It reciprocates in the axial direction in the cold finger (2) at the same frequency as (5b) and a different phase.

When the pistons (5a) (5b) and the displacer (20) move with an appropriate phase difference, the working gas enclosed in the working chamber (26) constitutes a thermodynamic cycle known as the "reverse Stirling cycle". However, cold heat is mainly generated in the low temperature chamber (21). Regarding the above-mentioned "reverse Stirling cycle" and its cold generation principle, see "Cryocoolers" (G.Wal
ker, Plenum Press. New York, 1983). The principle will be briefly described below.

First, when the displacer (20) is located in the upper part of the cold finger (2), the pistons (5a) (5b) move inward and compress the entire working gas in the working chamber (26). The working gas in the compression chamber (17) passes through the connecting pipe (3),
The compression heat that flows into the high greenhouse (22) and is generated during compression during this time is the yoke (14), the housing (10), and the connecting pipe (3).
Heat is dissipated to the ambient air via Next, the displacer (20) moves downward, and the working gas in the high temperature chamber (22) moves to the low temperature chamber (21) through the regenerator (23) and the gas passage hole (24) at this time. (23) precools the working gas with the cold heat stored before the half cycle. Next, the pistons (5a) and (5b) move outward to expand the entire working gas in the working chamber (26). The working gas also expands in the low greenhouse (21) to generate cold heat in the low temperature chamber (21).
Next, the displacer (20) moves upward, and the working gas in the low temperature chamber (21) moves to the high temperature chamber (22) through the regenerator (23) and the gas passage hole (24). At this time, the regenerator (23) is precooled by the working gas. After that, the pistons (5a) and (5b) move inward again, the compression of the working gas starts, and the same cycle is repeated. Since the compression and expansion of the working gas here are carried out while receiving work from the pistons (5a) (5b) and giving work to the pistons (5a) (5b), respectively, the working gas is heated during compression. And absorbs heat from the outside during expansion. As described above, when the displacer (20) is located in the upper part of the cold finger (2), that is, when the volume of the low temperature chamber (21) is small, the working gas is compressed and the displacer (20) is adversely affected. ) Is located in the lower part of the cold finger (2), that is, when the volume of the low temperature chamber (21) is large, the working gas expands. The expansion of the cold finger (2) takes heat from the outside of the tip of the cold finger (2) to cool the object to be cooled.

[Problems to be Solved by the Invention] The conventional device as described above has the following problems. Since the assembly consisting of the piston and the movable coil is positioned by the support spring, FIG. 7 is a model diagram of the above vibration system, which constitutes a spring-mass vibration system with one degree of freedom. In the figure, m is the mass of the assembly consisting of each piston and moving coil, K is the spring constant of the support spring, and f ₀ is the resonance frequency of the vibration system.

f ₀ is given by m and K, Is shown.

Therefore, for example, when installed in an environment such as an aircraft or a vehicle that receives vibration from the outside, when vibration having a component of f = f _{0 in the} piston axial direction is applied to the conventional device, the assembly consisting of the piston and the movable coil is Resonating, as shown in FIG. 7, the assembly of the first piston and the first moving coil, the assembly of the second piston and the second moving coil, and the working gas in the compression chamber are integrated, It vibrates in the same direction with the same period and phase. Since the damping force is small in this resonance, the resonance magnification is large and the vibration has a large co-width.

Therefore, when a large vibration is applied in the axial direction of the piston from the outside, the assembly consisting of the piston and the movable coil vibrates greatly in the same direction at the same period and in the same phase, and eventually collides with the housing or the yoke to generate noise. However, there was a problem that parts were lost.

The present invention has been made to solve the above problems, and prevents the occurrence of noise and loss of parts by preventing the resonance of the assembly including the piston and the movable coil from becoming large even when an external vibration is applied. It is a thing.

[Means for Solving the Problems] In the refrigerator according to the present invention, damping coils are added to the sleeves of the two moving coils, and the two moving coils move in the same direction in the magnetic field created by the permanent magnets. Only when moving,
Attenuation coil of two moving coils is electrically connected so that the current flowing in the attenuating coil by the voltage induced in the attenuating coil by the magnetic field generates Lorentz force in the direction that hinders the movement of the moving coil. Is.

Another invention of the present invention is that, in order to use the sleeves of the two moving coils as damping coils, the sleeve is made of a cylindrical conductor provided with linear or spiral slits, and two moving coils are used. Only when moving in the same direction in the magnetic field created by the permanent magnets, the voltage induced in the sleeve as a damping coil by the magnetic field generates a Lorentz force in the direction in which the current flowing in the sleeve hinders the movement of the moving coil. The two sleeves, which serve as damping coils, are electrically connected so that they flow in the same manner.

[Operation] In the present invention, when the two moving coils move in the same direction in the magnetic field created by the permanent magnet, a current is caused to flow in the attenuating coil due to the voltage induced in the attenuating coil by the magnetic field, Since the Lorentz force is generated in the damping coil in the direction that hinders the movement of the moving coil,
The assembly consisting of the piston and the moving coil does not vibrate greatly even if it receives a large vibration from the outside.

Similarly, in another invention of this invention, when the two moving coils move in the same direction in the magnetic field created by the permanent magnets, the voltage induced in the sleeve as the damping coil by the magnetic field causes Since a Lorentz force is generated in the sleeve in the direction in which the current flows and the movement of the movable coil is hindered, the assembly including the piston and the movable coil does not vibrate greatly even if a large external vibration is applied. Further, since the sleeve is used as a damping coil, no new space is required, so that the magnetic circuit does not have to be upsized.

[Embodiment] FIG. 1 is a view showing an embodiment of the present invention, in which a cold finger (2) and a connecting pipe (3) are exactly the same as those of a conventional device, and a compressor (1) is Only the moving coils (8a) and (8b) differ from the conventional device, and the other configurations are exactly the same. In the device of the present invention, the first damping coil (27a) is added to the first movable coil (8a), and the second damping coil (27a) is added.
The second damping coil (27b) is added to the moving coil (8b) of No. 2, and the two moving coils (8a) and (8b) move in the same direction in the magnetic field created by the magnetic circuit (15). Only when
In order to generate a Lorentz force in the direction in which the current flowing in the damping coils (27a) (27b) by the voltage induced in the damping coils (27a) (27b) by the magnetic field hinders the movement of the moving coil, The attenuation coils (27a, 27b) are electrically connected. FIG. 2 shows an example of connection of two damping coils (27a) (27b). In the figure, the thin solid arrow A is the magnetic field direction, the thin broken arrow B is the current direction, the thick solid arrow C is the moving direction of the moving coil, and the thick broken arrow D is the Lorentz acting on the damping coils (27a) (27b). This is the direction of force, and the compressor (1) is externally connected to the piston (5a) (5
b) The figure shows the case where a large vibration is applied in the axial direction.
This figure is a connection example when the directions of the magnetic fields applied to the two moving coils (8a) (8b) are opposite to each other. In this case, as shown in the figure, the two moving coils (8a) (8b) ) Move in the same direction as the damping coils (27a) (2
7b) should be connected so that the directions of currents ia and ib are opposite to each other. On the other hand, two moving coils (8a)
When the directions of the magnetic fields applied to (8b) are the same, the two moving coils (8a) (8b) flow through the respective damping coils (27a) (27b) when moving in the same direction. The connection may be made so that the currents flow in the same direction.

Next, the operation of the device of the present invention will be described. The principle of generating refrigeration is exactly the same as the conventional device in Fig. 6, but the compressor (1) receives a large vibration in the axial direction of the pistons (5a) (5b) from the outside, and the pistons (5a) (5b) When the assembly consisting of the moving coils (8a) and (8b) begins to oscillate in the same direction and in the same phase, a voltage is applied to the damping coils (27a) (27b) by the magnetic field created by the magnetic circuit (15). It is induced, and as a result, a second coil is applied to the damping coils (27a) (27b).
An electric current flows in the direction shown in the figure. Due to this current, a Lorentz force is generated in the damping coils (27a) (27b) in a direction that hinders the movement of the movable coils (8a) (8b). When vibration is applied from the outside in the axial direction of the pistons (5a) (5b), this Lorentz force becomes a damping force, and the same direction of the assembly consisting of the pistons (5a) (5b) and the moving coils (8a) (8b), Since the vibrations of the same phase are suppressed, it is possible to solve the problem that they collide with the housing (10) or the yoke (14) to generate noise and damage the parts. On the other hand, in the normal freezing generation operation, if the two moving coils (8a) (8b) vibrate in opposite directions with the same amplitude, they are induced in the two damping coils (27a) (27b). Since the applied voltages cancel each other, no current flows through the damping coils (27a) (27b), and the moving coil (8a)
a) Lorentz force that prevents the movement of (8b) is not generated.

FIG. 3 is a diagram showing another embodiment of the present invention.
In this embodiment, the sleeves (7a) and (7b) of the two movable coils (8a) and (8b) are respectively attached to the damping coils (27a) and (27b).
The sleeves (7a) and (7b) are made of a cylindrical conductor, and the sleeves (7a) and (7b) are provided with linear slits as shown in FIG. 4 or as shown in FIG. Such a spiral slit S is provided. 4 and 5 show an example of electrical connection of the two sleeves (7a) and (7b).
In the figure, the thin solid arrow A indicates the magnetic field direction, the thin broken arrow B indicates the current direction, and the thick solid arrow C indicates the moving direction of the movable coil.
The thick broken arrow D is the direction of the Lorentz force acting on the sleeves (7a) (7b), and illustrates the case where the compressor (1) receives a large vibration from the outside in the axial direction of the pistons (5a) (5b). There is. This figure is a connection example when the directions of the magnetic fields applied to the two moving coils (8a) and (8b) are opposite to each other.
In this case, as shown, two moving coils (8a)
Connection may be made so that the directions ia, ib of the currents flowing through the sleeves (7a), (7b) are opposite to each other when (8b) moves in the same direction. On the other hand, when the magnetic fields applied to the two moving coils (8a) (8b) are in the same direction, when the two moving coils (8a) (8b) move in the same direction, the respective sleeves are moved. (7a) and (7b) may be connected so that the directions of currents ia and ib are the same.

Next, the operation of the device of another invention of the present invention shown in FIG. 3 will be described. The principle of generating refrigeration is exactly the same as the conventional device in Fig. 6, but the compressor (1) receives a large vibration in the axial direction of the pistons (5a) (5b) from the outside, and the pistons (5a) (5b) When the assembly consisting of the movable coil (8a) and moving coil (8b) starts to vibrate in the same direction and in the same phase, the magnetic field created in the magnetic circuit (15) causes the sleeve (7a) (7b) to move.
A voltage is induced on the sleeve (7a) (7
Current flows in b) in the directions shown in FIGS. 4 and 5.
Due to this current, a Lorentz force is generated in the sleeves (7a) and (7b) in a direction that hinders the movement of the movable coils (8a) and (8b). When vibration is applied from the outside in the axial direction of the pistons (5a) (5b), this Lorentz force becomes a damping force, and the assembly of the pistons (5a) (5b) and the moving coils (8a) (8b) moves in the same direction. Since the vibration of the phase is suppressed, it is possible to solve the problem that these collide with the housing (10) or the yoke (14) to generate noise or damage to parts. On the other hand, in the normal freezing generation operation, when the two moving coils (8a) and (8b) vibrate in opposite directions with the same amplitude, they are induced in the two sleeves (7a) and (7b). Since the voltages tend to cancel each other out,
No current flows through the sleeves (7a) and (7b), and the moving coil (8
a) Lorentz force that prevents the movement of (8b) is not generated.

Furthermore, in the invention shown in FIG. 3, the sleeves (7a) (7
Since b) is also used as the damping coils (27a) (27b), it is not necessary to newly widen the gaps (16a) (16b) of the magnetic circuit (15). When the gaps (16a) and (16b) are widened, the magnetic field in the gaps (16a) and (16b) weakens, so a larger powerful permanent magnet is required.
If used as a) and (27b), a magnetic circuit (15) of the same size as the conventional device can be used.

[Effects of the Invention] As described above, in the refrigerator according to the present invention, damping coils are added to the sleeves of the two moving coils,
Only when the two moving coils move in the same direction in the magnetic field created by the permanent magnet, the current flowing in the attenuating coil due to the voltage induced in the attenuating coil by the magnetic field Lorentz in the direction in which the moving coil is prevented from moving. Due to the simple structure of electrically connecting the damping coil of two moving coils so as to generate force, when vibration is applied from the outside in the axial direction of the piston, the assembly of the piston and the moving coil becomes the same. Since a damping force that suppresses vibrations in the same direction and phase is generated in the damping coil, the problem that the assembly consisting of the piston and the movable coil collides with the housing or yoke, generating noise, and causing component loss is solved. There is an effect that can be done.

Further, another invention of the present invention is made of a cylindrical conductor provided with sleeve sleeve straight lines or spiral slits of two moving coils, and is also used as a damping coil, so that the magnetic circuit is not upsized. It has the effect of being good.

[Brief description of drawings]

FIG. 1 is a sectional view showing a refrigerator according to an embodiment of the present invention, FIG. 2 is a view showing an example of electrical connection of the first and second damping coils of the present invention, and FIG. 3 is a view of the present invention. FIG. 4 is a sectional view showing a refrigerator according to another invention, FIGS. 4 and 5 are diagrams showing an example of electrical connection of a sleeve according to another invention of the present invention, and FIG. 6 is a sectional view showing a conventional refrigerator. FIG. 7 is a diagram showing a vibration model of one mass of a spring constituted by a piston, a movable coil, a sleeve and a support spring. In the figure, (4a) and (4b) are cylinders, (5a) and (5b) are pistons, (7a) and (7b) are sleeves, (8a) and (8b) are moving coils, (9a) and (9b) are conductors, (15) is a magnetic circuit,
(17) is a compression chamber, (18) is a low temperature cylinder, (20) is a displacer, (21) is a low temperature chamber, (22) is a high temperature chamber, (23) is a regenerator, and (27a) (27b) are damping coils. Indicates. The same reference numerals in the drawings indicate the same or corresponding parts.

Claims (2)

[Claims] 1. A first and a second cylinder, which are arranged coaxially with each other, and a conductor provided on a cylindrical sleeve, and an alternating current is passed through the conductor to reciprocate in a magnetic field created by a magnetic circuit. First and second moving coils that move, a first piston that is connected to the first moving coil and that reciprocates in the first cylinder, and the second piston that is connected to the second moving coil A second piston that reciprocates in the cylinder, and a volume provided by reciprocating the first piston and the second piston provided inside the first cylinder and the second cylinder. A variable compression chamber, a slender tubular low-temperature cylinder, a low-temperature chamber and a high-temperature chamber that divide the interior of the low-temperature cylinder into a displacer that reciprocates in the low-temperature cylinder, and a re-spooler installed inside the displacer. In a refrigerator equipped with a living vessel,
A first damping coil is added to the first moving coil, and a second damping coil is added to the second moving coil, so that the first and second moving coils generate a magnetic field of the magnetic circuit. Only when moving in the same direction, the currents flowing in the first and second damping coils by the voltage induced in the first and second damping coils by the magnetic field are
A refrigerator in which the first and second damping coils are electrically connected so as to generate a Lorentz force that hinders the movement of the movable coil. 2. A first and a second cylinder arranged coaxially with each other, and a conductor provided on a cylindrical sleeve, and an alternating current is passed through the conductor to reciprocate in a magnetic field created by a magnetic circuit. First and second moving coils that move, a first piston that is connected to the first moving coil and that reciprocates in the first cylinder, and the second piston that is connected to the second moving coil A second piston that reciprocates in the cylinder, and a volume provided by reciprocating the first piston and the second piston provided inside the first cylinder and the second cylinder. A variable compression chamber, a slender cylindrical low temperature cylinder, a displacer that divides the inside of the low temperature cylinder into a low temperature chamber and a high temperature chamber, and reciprocates in the low temperature cylinder, and is provided inside the displacer. In a refrigerator equipped with a regenerator, linear or spiral slits are provided on the sleeves of the first and second moving coils, and the first and second moving coils are arranged in the magnetic field created by the magnetic circuit. Only when moving in the same direction, the current flowing in the sleeves of the first and second moving coils due to the voltage induced in the sleeves of the first and second moving coils by the magnetic field is A refrigerator characterized in that sleeves of the first and second movable coils are electrically connected so as to generate a Lorentz force in a direction in which movement of the movable coil is impeded.