JPH0784959B2 - Stirling refrigerator expander - Google Patents

Description

The present invention relates to an expander for a Stirling refrigerator, which expands a refrigerant gas in an expansion chamber in a cylinder by reciprocating motion of a displacer to generate cryogenic level cold, The present invention relates to the structure of a regenerator (regenerative heat exchanger) housed in a displacer.

(Prior Art) This type of Stirling refrigerator has a structure as shown in FIG.
This is a combination of a linear motor type compressor (a) that pressurizes the refrigerant gas in a predetermined cycle and an expander (k) that expands the refrigerant gas pressurized by the compressor (a).
The compressor (a) includes a closed cylinder (c) formed in a casing (b), a piston (e) reciprocally fitted in the cylinder (c), and a piston (e). a linear motor (reciprocatingly driving a piston (e)) having a bobbin (h) connected to e), a coil (i) wound around the bobbin (h), and a magnet (g) forming a magnetic circuit. f) and a piston spring (j) elastically supporting the piston (e) so that the piston (e) can reciprocate, and the coil (i) is energized with an alternating current of a predetermined frequency to move the piston (e) into the cylinder (c). It is configured to reciprocate inside and to generate a gas pressure of a predetermined cycle in the compression chamber (d) at the tip of the inside of the cylinder (c).

On the other hand, the expander (k) has a cylinder (1), and the inside space of the cylinder (l) is defined as an expansion chamber (m) on the tip side and a working chamber (n) on the base side in the cylinder (l). A free displacer (o) that is partitioned into is reciprocally inserted. This displacer (o) has a built-in regenerator (o ₁ ) which communicates with the expansion chamber (m) and the working chamber (n) through the communication holes (o ₂ ) and (o ₃ ), respectively. Further, a displacer spring (p) which elastically supports the displacer (o) so as to reciprocate is disposed in the working chamber (n). (S) is a vacuum container to which the expander (k) is attached,
The flange (s ₁ ) is airtightly joined to the flange (r) at the base end of the cylinder (l). The working chamber (n) is connected to the compression chamber (d) of the compressor (a) through the blending pipe (q), and the displacer (o) is operated by the increasing and decreasing refrigerant gas pressure from the compressor (a). By reciprocating, the refrigerant gas is expanded in the expansion chamber (m) to generate cold in the cold head at the tip of the cylinder (l) (for example, "Refrigerat or for Cryogenic Sensor").
s ", see NASA Conference Publication 2287).

(Problems to be solved by the invention) By the way, in the expander (k) of the Stirling refrigerator, as shown in FIG. 2, the cylinder (l) of the regenerator (o ₁ ) built in the displacer (o). The base end is at room temperature (for example, 50 ° C = 323K), while the tip is at a very low temperature level of about 70K. It is desirable that the temperature gradient between the room temperature end and the low temperature end be large. The efficiency of (o ₁ ) is improved. This temperature gradient can be increased by increasing the heat transfer area of the regenerator (o ₁ ), but on the other hand, it causes problems such as an increase in pressure loss of the regenerator (o ₁ ). However, the object of the present invention, which cannot be said to be an effective solution, is to improve the temperature gradient on the base end side without introducing new problems by improving the method of applying the temperature gradient of the regenerator. To achieve and improve the performance of the regenerator.

(Means for Solving the Problem) In order to achieve the above object, the solution means of the invention according to claim (1) is to extend a heat station covering a cold head at the tip of the cylinder to the cylinder base end side, This heat station cools and holds the range where the gas moves in and out of the expansion chamber at the low temperature side end of the regenerator at a constant cryogenic level.

That is, according to the present invention, as shown in FIG. 1, a cylinder (2) having a cold head (3) at the tip, and a cylinder (2) elastically supported so as to be capable of reciprocating, are provided in the cylinder (2). A displacer (5) for partitioning and forming a working chamber (12) on the base end side and an expansion chamber (13) on the tip side, and a displacer (5) built in the working chamber (12) and the expansion chamber (13). With a regenerator (9) in communication,
Assuming an expander of a Stirling refrigerator in which the refrigerant gas is expanded in the expansion chamber (13) in accordance with the reciprocating movement of the displacer (5) to generate cryogenic cold of the cold head (3). To do.

And, the feature is that the cold head (3) is provided with a heat station (17), and the heat station (17) reciprocates the displacer (5) in the regenerator (9) and the expansion chamber (13). The range (A) in which the gas flows between and to extends to the base end side of the cylinder (2) to the position where it moves at the stroke end of the displacer (5) on the base end side of the cylinder (2).

Further, the solution means of the invention according to claim (2) makes the low-temperature side and the room-temperature side of the regenerator have different matrix characteristics, and the low-temperature side matrix has a higher thermal conductivity than the room-temperature side.

That is, specifically, the present invention, as shown in FIG. 3, is a regenerator (comprising a large number of matrices (10) and (11) filled in the displacer (5) for the expander of the above premise. On the tip side of 9), in the range (A) in which gas moves between the displacer (5) and the expansion chamber (13) along with the reciprocating movement of the displacer (5), rather than the base side matrix (11) made of stainless steel, for example. A matrix (10) having a high thermal conductivity, such as copper, is filled.

Further, in the invention according to claim (3), as shown in FIG. 4, a matrix accommodating space (7b) is formed in the head (7) for closing the tip of the displacer (5), and the space (7b) is formed in the space (7b). The same matrix (10) of copper or the like having high thermal conductivity as described above is accommodated.

In the invention according to claim (4), as shown in FIG. 5, the regenerator (9) is composed of a large number of metal meshes (10a), (10b) packed in layers in the displacer (5). A mesh (10b) that is coarser than the base end side is placed in the range (A) in which gas moves between the expansion chamber (13) along with the reciprocating movement of the displacer (5) on the tip side of the regenerator (9). Fill.

In the invention according to claim (5), as shown in FIG. 6, as in the invention according to claim (3), the matrix accommodation space (7b) is provided in the head (7) at the tip of the displacer (5). To form a rough metal mesh (10b) in the space (7b).

When the displacer (5) moves forward from the neutral position (M) to the tip side by half the stroke, the gas in the expansion chamber (13) enters the regenerator (9) and, conversely, during the backward movement. When the displacer (5) retreats from the neutral position (M) to the base end side of the cylinder (2) by half the stroke, gas comes out of the regenerator (9) and enters the expansion chamber (13). Therefore, the above-mentioned "range (A) in which gas moves to and from the expansion chamber (13) as the displacer (5) reciprocates in the regenerator (9)" is, in other words, the regenerator (9). It can be said that the range is away from the tip end side to the base end side by approximately the stroke of the displacer (5).

(Operation) With the above configuration, in the invention according to claim (1), the displacer (5) in the cylinder (2) is operated when the expander is operating.
The gas is expanded in the expansion chamber (13) by the reciprocating motion of the cylinder, and the cold head (3) at the tip of the cylinder (2) is cooled to an extremely low temperature level. Along with this, the heat station provided in the cold head (3) (17) is also cooled. In the heat station (17), the range (A) in which the gas moves to and from the expansion chamber (13) along with the reciprocating movement of the displacer (5) in the regenerator (9) is the cylinder (2) of the displacer (5). Since the heat station (17) extends to the position where it moves at the stroke end on the base end side, the gas transfer range (A) is always cooled regardless of the reciprocating movement of the displacer (5), and the range (A).
Will be kept at a cryogenic level. Therefore,
In the regenerator (9), a temperature gradient from room temperature to an extremely low temperature level is provided in the base end side portion excluding the gas traffic range (A), and the temperature gradient becomes large, so that the performance of the regenerator (9) is improved. improves. Also, this large temperature gradient is due to the gas traffic range (A) at the tip of the regenerator (9).
Since it occurs in the portion other than the above, the range is relatively short, and the pressure loss does not increase so much.

In the invention according to claim (2), the gas transfer area (A) on the tip side of the regenerator (9) is filled with a matrix (10) having a high thermal conductivity, for example, made of copper, and the remaining room temperature side portion is heated. Since the proximal end side matrix (11) made of, for example, stainless steel or the like having a low conductivity is filled, the temperature of the gas is likely to decrease, which can increase the temperature gradient. On the other hand, since the matrix (10) in the gas traffic range (A) has a high thermal conductivity,
The temperature of the matrix (10) is kept cold at a cryogenic level. Therefore, the same effect as the above can be obtained.

In the invention according to claim (3), the matrix containing space (7b) of the head (7) for closing the tip of the displacer (5) has a matrix (1) made of copper or the like having a high thermal conductivity.
Since 0) is stored, there is an advantage that the temperature at the tip of the regenerator (9) can be more stably maintained at the cryogenic level.

In the invention according to claim (4), the mesh (10b) filled in the gas traffic range (A) at the tip of the regenerator (9)
Is coarse, the heat exchange efficiency with the gas is low. On the other hand, since the remaining mesh (10a) is fine, the heat exchange efficiency with the gas is good and the gas is easily cooled. Therefore, the same effect as the above can be obtained.

Further, in the invention according to claim (5), the matrix accommodation space (7) of the head (7) at the tip of the displacer (5).
Since the coarse metal mesh (10b) is housed in b), the same operational effect as the invention according to claim (3) can be obtained.

First Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

In FIG. 1, (1) shows an expander of a free displacer type Stirling refrigerator according to a first embodiment of the present invention. This expander (1) is a linear motor compressor (31) and a connecting pipe (30). Are connected by. The above compressor (31)
Has the same configuration as that described in the section “Prior Art” (see FIG. 7), and detailed description thereof will be omitted here.

The expander (1) includes a bottomed cylindrical cylinder (2) having a closed tip, and a mounting flange (18) externally fitted to the outer circumference of the cylinder (2) at the base end side. . The base end opening of the cylinder (2) is airtightly closed by the closing member (4), and the tip end of the cylinder (2) is a cold head (3). A free displacer (5) is reciprocally fitted in the cylinder (2), and the displacer (5) allows the inside of the cylinder (2) and the working chamber (12) on the base end side of the cylinder (2) and the tip end. Side expansion chamber (13)
It is divided into sections.

The displacer (5) is provided with a case (8) in which openings at both ends of a cylindrical body made of a thin metal such as stainless steel are closed airtightly by the heads (6) and (7), respectively. Regenerator inside (9)
(Regenerative heat exchanger) is housed. In this regenerator (9), a large number of copper disc meshes (10), (10), ... As a regenerator matrix are stacked in a case (8) in the longitudinal direction (axial direction) and filled. It was done.

The heads (6) and (7) respectively include a regenerator (9) in a case (8), an expansion chamber (13) and a working chamber (1).
Communication holes (6a), (7a) communicating with 2) are opened, and when the low-temperature refrigerant gas expanded in the expansion chamber (13) is directed to the working chamber (12), the regenerator (9) is caused by the refrigerant gas. ) Is stored and cold heat is stored therein, and conversely, when the refrigerant gas at room temperature goes from the working chamber (12) to the expansion chamber (13), the regenerator (9) cools the gas.

In addition, the displacer (5) is provided in the working chamber (12).
A displacer spring (16) made of a coil spring that elastically supports so as to reciprocate is disposed. The spring (16) includes a spring stopper (4a) formed on the distal end side (displacer (5 side)) of the closing member (4) and the base end of the room temperature side head (6) in the case (8) of the displacer (5). It is erected so as to expand and contract with the spring stopper (6b) that forms the displacer (5) with a predetermined frequency determined by the spring constant of the spring (16) and the cycle of gas pressure fluctuations of the compressor (31). ) Determines the reciprocating motion mode.

On the other hand, the attachment flange (18) is for attaching the expander (1) to the vacuum container (19), and is the cylinder (2).
It consists of a boss part (18a) externally fitted to the base end and a flange part (18b) formed at the end part of the cylinder (2) tip side of the boss part (18a), and the cylinder (2) tip side surface of the flange part (18b). An annular fitting groove (18c) for fitting the seal ring (20) is formed concentrically therewith. The vacuum container (19) has a bottomed cylindrical shape into which the cylinder (2) can be inserted with a certain gap, and the opening end thereof has a flange having the same diameter as the flange portion (18b) of the mounting flange (18). A portion (19a) is formed, and both flange portions (18b) and (19a) are brought into close contact with each other to seal the inside of the vacuum container (19).

A gas inlet (4b) communicating with the working chamber (12) in the cylinder (2) is formed in the center of the closing member (4) so as to penetrate along the cylinder axis direction. Is connected to the compressor (31) by connecting and sealing a coupling pipe (30). The refrigerant gas pressure from the compressor (31) causes the displacer (5) to reciprocate to expand the refrigerant gas into the expansion chamber. The cold head (3) at the tip of the cylinder (2) is made to generate cold by expanding at (13).

Further, the cold head (3) at the tip of the cylinder (2) is integrally attached with a heat station (17) having a cap shape capable of transferring heat thereto. And
The gas in the expansion chamber (13) moves in and out of the regenerator (9) as the displacer (5) reciprocates, and the gas flows back and forth between the regenerator (9) and the expansion chamber (13). As a feature of, the heat station (17) is
When the displacer (5) is located at the stroke end and the base end side of the cylinder (2), the gas transfer range (A) at the tip of the regenerator (9) (shown by the hatched dashed line in the figure)
At the base end side of the cylinder (2), the base end side of the cylinder (2) extends to a position where the end part on the base end side of the cylinder is positioned.

Incidentally, (14) is a room temperature side seal arranged around the room temperature side head (6) of the displacer (5), and (15) is a low temperature side seal similarly arranged around the low temperature side head (7).

Next, the operation of the above embodiment will be described.

With the operation of the refrigerator, the piston reciprocates in the cylinder due to the operation of the linear motor in the compressor (31), and the reciprocating movement of the piston increases or decreases the volume of the compression chamber.
The refrigerant in the compression chamber is pressurized in a predetermined cycle to generate a pressure wave in a predetermined cycle. Since the compression chamber communicates with the working chamber (12) of the expander (1) through the coupling pipe (30), when the pressure of the compression chamber becomes high, the pressurized refrigerant gas is discharged into the working chamber (12). The pressure in the working chamber (12) is increased by being supplied to the working chamber (12). This increase in pressure causes the working chamber (12) and expansion chamber (1
3), a pressure difference causes the displacer (5) to move from the neutral position (M) of the stroke to the tip side of the cylinder (2) while extending the displacer spring (16), and the expansion chamber (13). ) Pressure rises. Since the working chamber (12) communicates with the expansion chamber (13) through the regenerator (9) in the displacer (5), the gas is cooled through the regenerator (9) in the next stage. It flows into the expansion chamber (13), and both chambers (13),
The pressure difference in (12) disappears, and the displacer (5) moves to the base end side of the cylinder (2) by the contracting force of the spring (16) and returns to the original neutral position (M). Immediately thereafter, the piston of the compressor (31) retracts and the pressure in the compression chamber drops. Therefore, the refrigerant gas in the working chamber (12) returns to the compressor (31) via the coupling pipe (30), and the pressure in the working chamber (12) becomes lower than that in the expansion chamber (13). This working chamber (12)
The displacer (5) moves the neutral position (M) toward the base end of the cylinder (2) while the displacer spring (16) contracts due to the pressure difference between the expansion chamber (13) and the expansion chamber (13). The refrigerant gas is adiabatically expanded to generate cold. In the next stage, the expanded gas flows from the expansion chamber (13) through the displacer (5) toward the working chamber (12) while applying cold heat to the regenerator (9), and both chambers (12), The differential pressure in (13) disappears and the displacer (5) moves to the tip side of the cylinder (2) by the extension force of the spring (16) and returns to its original position. By the above, one cycle is completed, and thereafter, by repeating the same cylinder, the cold head (3) at the tip of the cylinder (2) and the heat station (17) integrated with it are gradually cooled to the cryogenic level.

The heat station (17) has an expansion chamber (13) at the tip of the regenerator (9) when the displacer (5) is at the stroke end on the base end side of the cylinder (2).
Since the gas transfer range (A) extends to the base end side of the cylinder (2) to the position where the gas transfer range (A) is positioned, the gas transfer range (A) is always at a cryogenic level regardless of the reciprocating movement of the displacer (5). Cooled by the station (17), its gas temperature is kept at a cryogenic level. Therefore,
As shown by the solid line in FIG. 2, in the regenerator (9), a temperature gradient from the normal temperature portion to the low temperature portion is generated in a portion other than the gas traffic range (A) where the cryogenic level is obtained, and the temperature gradient becomes large. Therefore, the performance of the regenerator (9) is improved.

Further, since a large temperature gradient is generated in a short range excluding the gas traffic range (A) at the tip of the regenerator (9), the pressure loss does not increase.

(Second Embodiment) FIG. 3 shows a second embodiment (note that in each of the following embodiments,
The same parts as those in FIG. 1 are designated by the same reference numerals and detailed description thereof is omitted), and the structure of the regenerator (9) is changed.

That is, in this embodiment, the heat station (1) provided on the cold head (3) at the tip of the cylinder (2) is
7 ') is different from the above embodiment and has a normal length. Instead, there are two types of regenerator matrices filled in the case (8), and heat is applied to the range (A) where gas flows between the regenerator (9) and the expansion chamber (13). While a large number of copper meshes (10), (10), ... Having a large conductivity are packed in a laminated state, the remaining room temperature side portion has a large number of large thermal conductivity and a large gas conduction area. The stainless steel meshes (11), (11), ... Of are filled in a laminated state.

Therefore, in this embodiment, the thermal conductivity of the copper meshes (10), (10), ... Filled in the gas traffic area (A) on the tip side of the regenerator (9) is large,
The temperature is kept cold at a cryogenic level. On the other hand, since the stainless steel meshes (11), (11), ... On the base end side of the cylinder (2) have poor thermal conductivity and a large heat transfer area, the temperature of the gas is likely to drop. By this,
There is a temperature gradient in the filling part of the stainless steel mesh (11), (11), ...
The same effect as in the above embodiment can be obtained.

(Third Embodiment) FIG. 4 shows a third embodiment, in which the copper mesh (10), (1
The head (7 ') on the tip side of the displacer (5) is also filled with 0), ....

That is, the low temperature side head (7 ') of the displacer (5) is composed of a bottomed circular box-shaped member having an opening on the base end side, and a communication hole (7a') is formed at the center of the bottom wall thereof. There is. Further, a matrix accommodating space (7b ') is provided inside the head (7'), and a large number of disc-shaped copper meshes (10) similar to the tip of the case (8) are also provided in this space (7b '). , (10), ... are stacked and filled.

In this embodiment, the head mesh (7 ') on the tip side of the displacer (5) also has a copper mesh (10) having a large thermal conductivity,
Since (10), ... Are accommodated, the temperature at the tip of the regenerator (9) can be more stably maintained at a cryogenic level as compared with a normal head structure (fourth embodiment). An example is shown, in which the regenerator matrices are all made of the same copper mesh (10), (10), ... Instead, the roughness of the mesh is changed between the tip side and the base side.

That is, a large number of coarse copper meshes (10b), (10b), ... With small mesh numbers are filled in the gas traffic range (A) between the expansion chamber (13) on the tip side of the regenerator (9), On the other hand, in the rest of the room temperature side, fine meshes (10a), (10
a), ... are filled.

Therefore, by doing this, the regenerator (9)
Mesh (10) filled in the gas traffic area (A) at the tip
Since b), (10b), ... Are coarse, the heat exchange efficiency with the gas is low. Meanwhile, the remaining meshes (10a), (10a),
Since ... is fine, the heat exchange efficiency with the gas is good, and the gas is easily cooled. Therefore, the same effect as that of the second embodiment can be obtained.

(Fifth Embodiment) Further, as shown in FIG. 6, a matrix containing space (7b ') is formed in the head (7') at the tip of the displacer (5), and a coarse copper mesh is formed in the space (7b '). (Ten
b), (10b), ... May be housed, and the same effect as the third embodiment can be obtained.

(Effect of the invention) As described above, according to the invention according to claim (1), in the Stirling refrigerator, the heat station that covers the cold head at the tip of the cylinder has a gas transfer range with the expansion chamber of the regenerator. By extending to the cylinder base end side to the gas transfer range with the expansion chamber in the regenerator at the stroke end on the cylinder base side of the displacer, the gas transfer range is constantly cooled regardless of the reciprocating movement of the displacer, and the gas Can be maintained at a cryogenic level, without increasing pressure loss,
It is possible to improve the regenerator efficiency by increasing the temperature gradient from room temperature to the cryogenic level in the regenerator.

Further, in the inventions according to claims (2) and (3), the matrix material on the low temperature side and the room temperature side in the regenerator is made different, and the matrix on the low temperature side uses a material having a larger thermal conductivity than the room temperature side. In the inventions according to claims (4) and (5), a metal mesh that is coarser than the room temperature side is used on the low temperature side. Therefore, according to these inventions, the heat exchange between the matrix on the proximal side of the regenerator and the gas is smoothly performed, the temperature of the gas is easily lowered, and the temperature gradient can be increased, while the matrix of the gas traffic range is increased. It is difficult to exchange heat with the gas, and the temperature of the matrix is kept at a cryogenic level, so that the same effect can be obtained.

[Brief description of drawings]

1 and 2 show a first embodiment of the present invention, FIG. 1 is an enlarged sectional view of an expander, and FIG. 2 is a diagram showing temperature distribution of a regenerator. 3 to 6 are cross-sectional views of the main parts of the expander shown in the second to fifth embodiments of the present invention.
FIG. 7 is a sectional view showing a conventional example of a Stirling refrigerator. (1) ...... Expander (2) ...... Cylinder (5) ...... Displacer (7), (7 ') ...... Head (7b') ...... Matrix storage space (9) ...... Regenerator (10) ... ... Copper mesh (matrix) (10a) ... Fine copper mesh (matrix) (10b) ... Coarse copper mesh (matrix) (11) ... Stainless steel mesh (matrix) (12) ... Working chamber (13) ...... Expansion chamber (17) ...... Heat station (31) ...... Compressor

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Katsuhiko Yamada 1304 Kanaoka-machi, Sakai City, Osaka Daikin Industry Co., Ltd., Kanaoka Plant, Sakai Manufacturing Co., Ltd. (56) Reference JP-A-1-203852 (JP, A) JP A 62-223575 (JP, A)

Claims (5)

[Claims] 1. A cylinder (2) having a cold head (3) at its tip, and a cylinder (2) elastically supported so as to be capable of reciprocating, and a working chamber (12) on the base end side in the cylinder (2). A displacer (5) for partitioning and forming the expansion chamber (13) on the tip side, and a regenerator (9) built in the displacer (5) and communicating with the working chamber (12) and the expansion chamber (13). An expander for a Stirling refrigerator in which a cold gas (3) is chilled at an extremely low temperature by expanding a refrigerant gas in the expansion chamber (13) with the reciprocating movement of the displacer (5). , The cold station (3) has a heat station (1
7) is provided, and the heat station (17) has a range (A) in which gas flows to and from the expansion chamber (13) along with the reciprocating movement of the displacer (5) in the regenerator (9). An expander for a Stirling refrigerator, which extends to the base end side of the cylinder (2) to a position where it moves at the stroke end of 5) toward the base end side of the cylinder (2). 2. A cylinder (2) having a cold head (3) at its tip, and a cylinder (2) elastically supported so as to be able to reciprocate, and a working chamber (12) on the base end side in the cylinder (2). A displacer (5) for partitioning and forming the expansion chamber (13) on the tip side, and a regenerator (9) built in the displacer (5) and communicating with the working chamber (12) and the expansion chamber (13). An expander for a Stirling refrigerator in which a cold gas (3) is chilled at an extremely low temperature by expanding a refrigerant gas in the expansion chamber (13) with the reciprocating movement of the displacer (5). The regenerator (9) is composed of a large number of matrices (10), (11) filled in the displacer (5), and expands along with the reciprocating movement of the displacer (5) at the tip side of the regenerator (9). The scope (A) of gas is traffic between the chamber (13), the expander of the Stirling refrigerating machine, characterized in that the large matrix of thermal conductivity (10) is filled than proximally. 3. A matrix-accommodating space (7b) is formed in a head (7) that closes the tip of the displacer (5), and a matrix (10) having a high thermal conductivity is also accommodated in the space (7b). The expander for a Stirling refrigerator according to claim (2). 4. A cylinder (2) having a cold head (3) at its tip, and a cylinder (2) elastically supported so as to be capable of reciprocating, and a working chamber (12) on the base end side in the cylinder (2). A displacer (5) for partitioning and forming the expansion chamber (13) on the tip side, and a regenerator (9) built in the displacer (5) and communicating with the working chamber (12) and the expansion chamber (13). An expander for a Stirling refrigerator in which a cold gas (3) is chilled at an extremely low temperature by expanding a refrigerant gas in the expansion chamber (13) with the reciprocating movement of the displacer (5). The regenerator (9) includes a large number of metal meshes (10a), (10) filled in layers in the displacer (5).
b), and in the range (A) in which gas moves to and from the expansion chamber (13) along with the reciprocating movement of the displacer (5) on the tip side of the regenerator (9), a mesh that is rougher than the base side is formed. An expander for a Stirling refrigerator, which is filled with (10b). 5. A matrix housing space (7b) is formed in a head (7) having a closed distal end of the displacer (5), and a coarse mesh (10b) is also housed in the space (7b). An expander for a Stirling refrigerator according to claim 4.