JPH04143553A - Refrigerator - Google Patents

Abstract

PURPOSE:To prevent collision of a component due to an increase in the amplitude of a piston caused by an environmental temperature change by making a connecting tube communicate with a compressing chamber via two communicating tubes, and disposing the ends of each communicating tube respectively at sections provided with two clearance seals of the cylinder. CONSTITUTION:When an environmental temperature is largely varied, intrinsic value of a vibration system composed of pistons 5a, 5b, movable coils 9a, 9b, supporting springs 7a, 7b and operation gas is varied. If the pistons 5a, 5b start to vibrate in a large amplitude, the piston 5a is passed through the end 34a of a first communicating tube 33a, and the piston 5b is passed through the end 34b of a second communicating tube 33b. Then, since the end 34a of the tube 33a is blocked by a clearance seal 21a and the end 34b of the tube 33b is blocked by a clearance seal 21b, communication of operation gas between a compressing chamber 19 and other space is disturbed. The gas remaining in the chamber 19 enhances its spring effect as the pistons 5a, 5b approach to brake the pistons 5a, 5b.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention is directed to, for example, infrared detection elements heated to extremely low temperatures (for example, 80
This relates to a Stirling refrigerator that cools the refrigerator before and after.

[Prior Art] FIG. 2 shows an example of the configuration of a conventional Stirling refrigerator. In FIG. 2, a Stirling refrigerator is roughly divided into a compressor (1), a cold finger (2), and a connecting pipe (3) connecting these. The compressor (1) includes a first cylinder (4a) and a first piston (5a), and a second cylinder (4b) and a second piston (5b). 1st
The piston (5a) and the second piston (5b) are positioned by support springs (7a) and (7b), respectively,
First cylinder (4a) and second cylinder (4b)
It has a structure that reciprocates inside.

First piston (5a) and second piston (5b)
each includes a lightweight first sleeve (8) made of non-magnetic material.
a), the second sleeve (8b) is connected and the sleeve (8
A) and (8b) are wound with a conductor to form a first moving coil (9al) and a second moving coil (9b).

Moving coils (9a) and (9b) are housings (]0)
The first line (lla) extending outward through the wall of
, (llb).

It is connected to the second lead wires (12a), (], 2b), and these lead wires (lla), (llb),
(12a), (12b) have first electrical contacts (13a), (13b) and second electrical contacts (14a) (14b) on the outside of the housing (10). There are permanent magnets (15a) and (15b) inside the housing (10).
and a yoke (16), which constitute a magnetic circuit (J7). Moving coil (9a),
(9b) is a piston (5a) within a gap (18a) and a second gap (18b) provided in a magnetic circuit (17) consisting of permanent magnets (15a), (15b) and a yoke (16). , (5b) has a structure that allows reciprocating movement in the axial direction. Gap (18a).

A permanent magnetic field exists in (18b) in the radial direction transverse to the direction of motion of the moving coil.

Cylinder (4a), piston (5a), cylinder (4b).

The space partitioned off by the piston (5b) is called a compression chamber (19). The compression chamber (19) is filled with a high-pressure working gas such as helium. In order to prevent the working gas in the compression chamber (19) from passing through the gap between the cylinder (4a) and the screw head (5a) and the gap between the cylinder (4b) and the piston (5b), The gap between the cylinder (5a) and the gap between the cylinder (4b) and the piston (5h) are managed to be minute gaps of, for example, 50 um or less, and constitute the clearance sills (2ja) and (21b). In the conventional device, the end (32) is connected to the end (32) by a clearance seal (
21,a,) and the clearance seal (21b) to prevent the cylinder (4a) and cylinder (4a) from being blocked.
4b). The above is the configuration of the compressor (1).

On the other hand, the cold finger (2) has a cylindrical low-temperature cylinder (22) and a displacer (24) that slidably reciprocates within the low-temperature cylinder (22) and is engaged by a resonant spring (23). are doing. Low temperature cylinder (22)
The interior space is divided into two by a displacer (24), the space above the displacer (24) being called a low temperature room (25), and the space below it being called a high temperature room (26). A regenerator (27) and a gas passage hole (28) are provided inside the displacer (24), and a low temperature chamber (25) and a high temperature chamber (26) are connected to each other through the regenerator (27) and gas passage hole (28). The regenerator (27) is filled with a cold storage material (29) such as a copper wire mesh. Like the compressor (1), each chamber of the cold finger (2) is filled with a high-pressure working gas such as helium.

In order to prevent the working gas from passing through the gap between the low temperature cylinder (22) and the displacer (24),
A clearance seal (30) is provided in the gap between the displacer (24) and the displacer (24). The above is the configuration of the cold finger (2).

Compressor (1) compression chamber (19) and cold finger (2)
) The high temperature chamber (26) is connected to the connecting pipe (3) and the communication 'It
(20). Also a compression chamber (19),
The space inside the connecting pipe (3) and the communicating pipe (20), the low temperature chamber (25), the high temperature chamber (26), the regenerator (27), and the waste passage hole (28) are in communication with each other, and the entire space is Collectively, they are called the working chamber (3I).

The operation of the conventional refrigerator configured as described above will be explained. Electric contacts (
13a), (13b), (14a), (1
4b) and lead wires (Lla), (llb), (
When an alternating current is applied through coils (9a) and (12b), a gap (1
A Lorentz force acts in the axial direction due to the interaction with the permanent magnetic field in 8a) and (18b). As a result, the piston (5
a) and a moving coil (9a) and an assembly consisting of a piston (5b) and a moving coil (9b) move left and right in the axial direction of the piston.

Now, the first moving coil (9a) and the second moving coil (9a)
b) under the condition that the characteristics are the same and the strengths in the first gap (1, 8a) and the second gap (18b) are equally L.

First moving coil (9a) and second moving coil (9b)
When a sinusoidal current is applied that vibrates in opposite directions with the same amplitude, the two pistons (5a) and (5b) reciprocate inside the cylinders (4a) and (4b) in opposite directions, causing 9 operations. A sinusoidal wave is applied to the gas pressure in the chamber (31). A displacer (
24) and the regenerator (27), the displacer (24) including the regenerator (27)
reciprocates in the axial direction within the cold finger (2) at the same frequency and different phase as the pistons (5a) and (5b).

Pistons (5a), (5b) and displacer (
24) moves with an appropriate phase difference, the 9 working chambers (
The working gas enclosed in 31) constitutes a thermal cycle known as the "inverted Stirling cycle".

Cold heat is mainly generated in the cold room (25). Regarding the above-mentioned ``reverse Stirling cycle'' and its principle of generating cold and heat, there are 2 references in ``Recryocoolers'' (G,
er, plenun Press, New York
, 1983. pp. 95-177). The principle will be briefly explained below.

While the gas in the compression chamber (19) compressed by the pistons (5a) and (5b) flows through the connecting pipe (3), the heat of compression is cooled and the gas is transferred to the high temperature chamber (26) and the regenerator (27).
).

It flows into the gas passage hole (28). The working gas is supplied by a regenerator (2
7) is pre-cooled by the cold energy stored half a cycle before,
Enter the cold room (25). When most of the working gas enters the cold room (25), it begins to expand, and the cold room (25) begins to expand.
), the working gas returns to the compression chamber (1) in the reverse order while releasing cold energy to the regenerator (27).
Enter 9). At this time, heat is removed from the tip of the cold finger (2) to cool the outside thereof.

In this way, when most of the working gas returns to the compression chamber (19), compression begins again and the process moves to the first cycle. Through the process described above, the above-mentioned "reverse Stirling cycle" is completed and cold heat is generated.

Furthermore, in the refrigerator configured as described above, the movable part consisting of the piston (5a) and the movable coil (9a) and the movable part consisting of the piston (5b) and the movable coil (9b) are arranged in the same direction in opposite directions. Since it moves with amplitude, it has the advantage of canceling out the inertial force caused by reciprocating motion and not imparting vibration to the outside of the refrigerator.

[Problems to be Solved by the Invention] The conventional device as described above has the following problems. The assembly consisting of the piston and the moving coil constitutes a spring-mass vibration system with a degree of freedom due to the spring effect of the support spring and the working gas. FIG. 3 is a model diagram of the above vibration system. In the figure, 9m is the weight of the assembly consisting of each piston and moving coil, and □ is the spring constant I of the support spring.
KK indicates the spring constant of the working gas. However, the resiliency constant of the working gas is greatly affected by the temperature of the working gas, so when the environmental temperature changes, the eigenvalue of the vibration system changes,
The amplitude of the piston changes in response to the input.

For this reason, even if the input to the refrigerator is kept constant, if a large change in environmental temperature is applied to a conventional device, the amplitude of the pistons will increase and the pistons will collide with each other, or the moving coil will collide with the housing or yoke. However, there were problems such as noise and damage to parts.

The present invention has been made to solve this problem, and an object of the present invention is to provide a refrigerator that prevents collisions of parts due to an increase in the amplitude of the piston due to changes in environmental temperature.

[Means for Solving the Problems] A refrigerator according to the present invention communicates a connecting pipe and a compression chamber with two communicating pipes, and connects each communicating pipe eave end to two
It is placed in the area where the clearance seal of two cylinders is provided.

[Operation] In this invention, when the amplitude of the piston increases, the ends of the two communicating pipes are each closed by the clearance seal between the piston and the cylinder, so that the conventional flow of working gas between the compression chamber and other working chambers is prevented. is hindered. Therefore, the working gas remaining in the compression chamber enhances its spring effect and acts to brake the piston. The larger the amplitude of the piston, the greater the braking force, which prevents the piston or moving coil from colliding with the housing or yoke even if the refrigerator is installed in an environment subject to large temperature changes, reducing noise and component damage. It can be prevented.

Embodiment FIG. 1 shows an embodiment of the present invention. In FIG. 0, (1) to (19) and (21) to (31) are exactly the same as the conventional device. The connecting pipe (3) communicates with the compression chamber (19) through a first communicating pipe (33a) and a second communicating pipe (33b). First communication pipe (33
The end (34a) of a) is connected to the clearance seal (21a) of the cylinder (4a), and the end (34b) of the second communication pipe (33b) is connected to the clearance seal (21b) of the cylinder (4b). ) is placed in the area provided with.

In such a device, the pistons (5a), (5h), moving coils (9a), (9b), and support springs (7a), (7
b) When the eigenvalue of the vibration system constituted by the working gas changes and the pistons (5a) and (5b) begin to vibrate with large amplitude, the piston (5a)
33), and also passes through the end (34a) of the piston (5
b) passes through the end (34b) of the second communication pipe (33b), the end (34a) of the first communication pipe (33a) is secured to the second communication pipe (34b) by the clearance seal (21a).
The end (34b) of the clearance seal (21
b), which prevents the connection of working gas between the compression chamber (19) and other spaces. For this reason, the compression chamber (1
9) The working gas remaining in the piston (5a) and (5b)
), the closer the spring effect is to the piston (5a),
Brake (5b).

The larger the amplitude of the pistons (5a) and (5b), the greater the braking force, so even if the refrigerator is installed in an environment subject to large temperature changes, the pistons or moving coils will not collide with the housing or shaft. This prevents noise and damage to parts.

Effects of the Invention As explained above, according to the present invention, in the compressor of a refrigerator whose piston is driven by a permanent magnet and a moving coil,
The simple method of connecting the communication pipe and the compression chamber through two communication pipes and placing the ends of each pipe in areas with clearance seals inside the two cylinders allows vibration system vibration due to large fluctuations in environmental temperature. Even if the eigenvalue of changes and the piston amplitude increases, the increased piston amplitude itself causes the working gas in the compression chamber to apply a braking force to the piston, so the piston or moving coil will not collide with the housing or yoke. It is possible to prevent collisions, eliminate noise during collisions, and eliminate damage to parts that make up the refrigerator.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a refrigerator according to an embodiment of the invention, FIG. 2 is a sectional view showing a conventional refrigerator, and FIG. 3 is a piston,
FIG. 2 is a diagram showing a vibration model of a spring-mass system composed of a moving coil, a sleeve, a support spring, and a working gas. In the figure, (4a) and (4b) are cylinders, (
5a), (5b) are pistons, (7a), (7
b) is a support spring, (9a) and (9b) are moving coils, (10) is a housing, (17) is a magnetic circuit,
(19) is a compression chamber, (21a) and (21b) are clearance seals, (33a) and (33b) are communication pipes, and (34a) and (34b) are communication v (33a). (33b) shows the end. In addition. The same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] first and second cylinders arranged coaxially with each other;
first and second moving coils facing each other, provided in the magnetic flux created by the permanent magnet, and capable of reciprocating motion by flowing an alternating current; and connected to the first moving coil and inside the first cylinder. a first piston that reciprocates; a first clearance seal provided between the first cylinder and the first piston; and a first clearance seal that is connected to the second movable coil and moves inside the second cylinder. a second piston that reciprocates; a second clearance seal provided between the second cylinder and the second piston; and the first cylinder, the first piston, and the second cylinder. , and a compression chamber partitioned by the second piston;
a 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 a displacer that slideably reciprocates inside the low-temperature cylinder; a regenerator provided inside the displacer; In a refrigerator comprising a connecting pipe and a communicating pipe that communicate a chamber and the compression chamber, the connecting pipe and the compression chamber are communicated with each other through two communicating pipes, and the ends of the two communicating pipes are connected to the A refrigerator characterized in that the refrigerator is disposed in a portion inside the first cylinder where the first clearance seal is provided and a portion inside the second cylinder where the second clearance seal is provided.