JPH10288414A - Stirling refrigerator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate thermal strain of a cylinder or abnormal sound due to leakage of gas or a turbulent flow. SOLUTION: In a casing 46, before a cylinder 3 is assembled, a hole is opened, and a joint tube 45 is welded. In a cylinder 43, a cylindrical spigot is coaxially formed at an opening of a discharge hole 47. An inserting tube 44 is inserted to an innermost side of the spigot of the cylinder 43 assembled in the casting 46. A coupling tube 42 is press-fitting in an axial hole of the tube 44, and welded to the tube 44 and an outer end of the tube 45. Thus, welding heat is eliminated to be transferred to the cylinder 43 to eliminate thermal strain. The tube 44 is inserted to the innermost side of the spigot to eliminate leakage or turbulent flow of gas. The tubes 43 and 44 are shrink-fitted, the tubes 44, 43 are shrink-fitted or intermediately fitted, thereby eliminating decentering of the tubes 43, 44 from the hole 47.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an improvement of a Stirling refrigerator.

[0002]

2. Description of the Related Art Conventionally, there is a Stirling refrigerator as one of small refrigerators for cooling an atmosphere to an extremely low temperature. This Stirling refrigerator has a structure in which a compressor that compresses a refrigerant gas and an expander that expands the high-pressure refrigerant gas discharged from the compressor by reciprocating a displacer.

Hereinafter, the above Stirling refrigerator will be briefly described. FIG. 3 is a schematic sectional view of the Stirling refrigerator. The compressor 1 has a substantially symmetric structure with a plane including the axis of the refrigerant gas discharge hole 20 connected to the working chamber 17 of the expander 11 as a boundary.

In the compressor 1, a cylinder 3a having an outer peripheral surface along an inner peripheral surface of the casing 2 and a cylinder 3b having an axial hole 4 are provided at a central portion in the axial direction in a closed cylindrical casing 2. The connected double cylindrical cylinder 3 is housed.
A piston 5 having a disk 7 attached to one end is inserted into one end of the shaft hole 4 of the cylinder 3. Similarly, a piston 5 ′ having a disk 7 ′ attached to one end is inserted through the other end of the shaft hole 4. A compression chamber 6 is formed between the heads of the pistons 5, 5 '.

[0005] The coils 9, 9 'are formed on the outer peripheral surfaces of the cylinders 8, 8' extending from the outer peripheral edges of the discs 7, 7 'to the two cylinders 3a, 3b of the cylinder 3. This coil 9, 9 '
Together with the magnets 10 and 10 ′ provided at both ends of the outer peripheral surface of the cylinder 3 b of the cylinder 3, a linear motor is configured. Driven by this linear motor, the pistons 5, 5 'reciprocate synchronously with the assistance of the springs 21, 21'.

The expander 11 encloses a displacer 14 having a mesh-like cold storage material in a cylinder 12 having radiation fins 13 on the outer periphery, and seals the displacer 14 and the cylinder 12 with an annular sealing material 15. . Thus, the interior of the cylinder 12 is partitioned by the displacer 14 and the sealing material 15 into the expansion chamber 16 on the distal end side and the working chamber 17 on the proximal end side. The working chamber 17 communicates with the compression chamber 6 of the compressor 1 via a connection pipe 19. The base end of the displacer 14 is connected to the base end of the cylinder 12 by a spring 18 so that the displacer 14 is normally at a neutral position.

The above-structured Stirling refrigerator operates as follows. When an AC voltage is applied to the coils 9, 9 'of the compressor 1, the pistons 5, 5' move toward the axial center in the shaft hole 4, and the refrigerant gas in the compression chamber 6 is compressed. The high-pressure refrigerant gas is supplied to the discharge hole 20 and the connecting pipe 1.
9, the pressure is supplied to the working chamber 17 of the expander 11, and the pressure in the working chamber 17 increases. Then, the working chamber 17
And a pressure difference is generated between the working chamber 17 and the expansion chamber 16 which is communicated with the working chamber 17 via the cold storage material storage chamber of the displacer 14,
When this pressure difference exceeds the elastic force of the spring 18, the displacer 14 moves to the tip side of the cylinder 12.

When the displacer 14 reaches the tip of the cylinder 12, the high-pressure refrigerant gas in the working chamber 17 flows toward the expansion chamber 16 while being cooled by the regenerator material in the displacer 14, and the working chamber 17 and the expansion chamber are eventually formed. 16 and the same pressure. Then, the displacer 14 moves to the base end side of the cylinder 12 by the contraction force of the spring 18 and returns to the neutral position.

Next, each of the pistons 5, 5 'of the compressor 1 moves to the one end or the other end, and the pressure in the compression chamber 6 decreases. Then, the working chamber 1 of the expander 11
The refrigerant gas in 7 returns to the compression chamber 6 through the connection pipe 19 and the discharge hole 20, and the pressure in the working chamber 17 becomes lower than the pressure in the expansion chamber 16, and a pressure difference occurs between the two chambers 16 and 17. When the pressure difference exceeds the elastic force of the spring 18, the displacer 14 moves to the base end of the cylinder 12. As a result, the refrigerant gas in the expansion chamber 16 adiabatically expands, and the temperature decreases. The refrigerant gas thus cooled flows into the working chamber 17 while applying cold to the cold storage material in the displacer 14, and the working chamber 17 and the expansion chamber 16 have the same pressure. Then, the displacer 14 moves to the distal end side of the cylinder 12 by the extension force of the spring and returns to the neutral position. Thus, one refrigeration cycle ends.

FIG. 4 is an enlarged sectional view of a connecting portion between the compressor 1 and the connecting pipe 19 shown in a part A of FIG. The connection between the compressor 1 and the connection pipe 19 shown in FIG. 4 is performed by direct welding as described below. That is, the discharge hole 2 of the cylinder 3
A hole 22 having the same diameter as the outer diameter of the connecting pipe 19 is bored in the casing 2 coaxially with 0. Then, the distal end of the connecting pipe 19 is inserted into the hole 22, and the connecting pipe 19 and the casing 2 are welded.

FIG. 5 is an explanatory diagram of another connection method for connecting the compressor 1 and the connection pipe 19. The connection between the compressor 1 and the connection pipe 19 shown in FIG. 5 is performed by insertion welding as follows. That is, the holes 23, 2 having the same diameter as the outer diameter of the connecting pipe 19 are coaxial with the discharge hole 20 of the cylinder 3.
4 is pierced in the casing 2 and the cylinder 3. Then, the distal end of the connecting pipe 19 is inserted into the holes 23 and 24, and the connecting pipe 19 and the casing 2 are welded.

FIG. 6 is an explanatory view of another connection method for connecting the compressor 1 and the connection pipe 19. The connection between the compressor 1 and the connection pipe 19 shown in FIG. 6 is performed by the flange 25 as described below. That is, holes 26 and 27 for inserting the insertion tube 25 a of the flange 25 are formed in the casing 2 and the cylinder 3 coaxially with the discharge hole 20 of the cylinder 3. Further, a seat 29 having a hole 28 having the same diameter as the outer diameter of the insertion tube 25 a of the flange 25 is fitted and fixed to a concave portion 30 provided around the hole 26 of the casing 2. And
The connecting pipe 1 is inserted into the hole 28 of the seat 29 and the hole 27 of the cylinder 3.
The insertion tube 25a of the flange 25 into which one end of the 9 is press-fitted is inserted, and the flange 25 is fixed to the seat 29 with a screw. The leakage of the high-pressure gas from the discharge hole 20 of the cylinder 3 is caused by the O-rings 31 and 32 fitted in the groove at the distal end of the insertion tube 25a and the groove at the back of the head in the flange 25.
Sealed by.

[0013]

However, the conventional method of connecting the compressor 1 and the connecting pipe 19 has the following problems. That is, in the case of the direct welding shown in FIG. 4, the connecting pipe 19 and the cylinder 3 are not directly connected. Therefore, the high-pressure gas from the discharge hole 20 leaks into the casing 2 through the gap between the cylinder 3 and the casing 2 as shown by the arrow (B). There is a problem that the compression efficiency is reduced. The cylinder 3
In some cases, the center of the discharge hole 20 and the center of the hole 22 formed in the casing 2 do not coincide with each other, and since the tip of the connecting pipe 19 is merely inserted into the hole 22 of the casing 2, the connecting pipe 19 is There is also a problem that the reliability and the performance as a refrigerator are reduced due to the fact that the refrigerator may not be erected perpendicularly to the side surface of the refrigerator.

In the case of the insertion welding shown in FIG. 5, since the distal end of the connecting pipe 19 is inserted into the hole 24 of the cylinder 3 for welding, welding heat is applied through the connecting pipe 19 to the cylinder 3.
, Heat distortion occurs in the cylinder 3. Therefore, there is a problem that the reliability and performance as a refrigerator are reduced.

In the case of the flange 25 shown in FIG.
There is a problem that the number of parts increases, which causes a cost increase. Since the O-ring 31 is fitted between the insertion tube 25a of the flange 25 and the hole 27 of the cylinder 3, misalignment occurs between the shaft hole 25b of the flange 25 and the discharge hole 20 of the cylinder 3. May be. In that case, a turbulent flow occurs in the gas discharged from the compressor 1, which causes abnormal noise.

SUMMARY OF THE INVENTION An object of the present invention is to provide a highly reliable and efficient Stirling refrigeration system which has no thermal distortion in a cylinder of a compressor and does not generate abnormal noise caused by leakage of high-pressure gas or turbulent flow of discharge gas. To provide machines.

[0017]

Means for Solving the Problems To achieve the above object, an invention according to claim 1 includes a compressor, an expander that expands refrigerant gas from the compressor to cool it to an extremely low temperature,
In a Stirling refrigerator having a connecting pipe connecting the compressor and the expander, a joint pipe connected to a hole provided in a casing of the compressor and welded to the casing, and a cylinder incorporated in the casing A seal part formed coaxially with the discharge hole at the opening of the discharge hole of the refrigerant gas, the joint pipe, an insertion pipe penetrating the hole and inserted into the seal part, and the connection pipe, It is characterized by being press-fitted into the outer end of the insertion tube and welded to the outer end of the insertion tube and the outer end of the joint tube.

According to the above construction, welding of the joint pipe and the casing is performed before the cylinder is assembled in the casing, and welding of the connecting pipe press-fitted into the insertion pipe to the insertion pipe and the joint pipe is performed by the cylinder. Performed at a distance from the Therefore, welding heat is not transmitted to the cylinder, and no thermal distortion occurs in the cylinder. Further, the connection pipe is press-fitted into the insertion pipe, and the insertion pipe is inserted into the seal portion of the cylinder. Therefore, the connecting pipe, the insertion pipe, and the discharge hole are not misaligned, and the refrigerating capacity is not reduced. Further, the insertion tube into which the connecting tube has been press-fitted is inserted into the seal portion of the cylinder. Therefore, there is no gap between the connection pipe and the cylinder, and the refrigerant gas does not leak and the refrigeration capacity does not decrease.

According to a second aspect of the present invention, in the Stirling refrigerator of the first aspect, the insertion end of the insertion tube into the intaglio portion is in contact with the bottom surface of the intaglio portion. Features.

According to the above configuration, no gap is formed between the insertion end of the insertion tube inserted into the seal portion of the cylinder and the bottom surface of the seal portion. Therefore, the refrigerant gas discharged from the discharge hole of the cylinder does not become turbulent due to a sudden change in the flow path diameter, and no abnormal noise is generated and the refrigeration capacity is not reduced.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments. FIG. 1 is an enlarged cross-sectional view of a connecting portion between a compressor and a connecting pipe in the Stirling refrigerator of the present embodiment. In FIG. 1, 41 is a compressor,
Reference numeral 42 denotes a connecting pipe. The compressor 41 has the same basic structure as the compressor 1 shown in FIG. 3, and a cylinder 43 is housed in a casing 46.

In the present embodiment, the connecting pipe 42
Through the insertion pipe 44 and the joint pipe 45 to the compressor 4
It is attached to one cylinder 43 by welding.
Here, the inner diameter of the insertion pipe 44 is the same as the inner diameter of the discharge hole 47 for discharging the refrigerant gas, and is slightly smaller than the outer diameter of the connecting pipe 42. The inner diameter of the joint pipe 45 is substantially the same as the outer diameter of the insertion pipe 44. Hereinafter, a method of connecting the connection pipe 42 will be described with reference to FIG.

First, the cylinder 43 is connected to the casing 46.
Prior to assembling into the inside, at the position of the casing 46 where the discharge hole 47 is located when the cylinder 43 is later installed,
A hole 48 having the same diameter as the outer diameter of the joint pipe 45 is formed. Then, one end of the joint pipe 45 is inserted into the hole 48, and the outer periphery of the joint pipe 45 and the periphery of the hole 48 of the casing 46 are welded. In this case, since the casing 46 is separated from the cylinder 43, the welding heat is transmitted to the cylinder 43 and
No thermal distortion occurs. Further, since the casing 46 is separated from the cylinder 43, the welding can be performed with good workability, and the joint pipe 45 can be easily formed.
Can be erected perpendicular to the casing 46.

On the other hand, in the cylinder 43, a hole 49 coaxial with the discharge hole 47 is formed in the opening of the discharge hole 47 in advance. In this case, the inner diameter of the hole 49 is set so that one end of the insertion tube 44 can be connected with a tight fit to an intermediate fit. That is, the hole 49 constitutes the above-described intaglio portion. After that, the cylinder 43 is assembled into the casing 46 to which the joint pipe 45 is attached so that the joint pipe 45 and the hole 49 of the cylinder 43 are coaxial. In this case, the length from the outer end of the joint pipe 45 to the bottom of the hole 49 in a state where the cylinder 43 is incorporated in the casing 46 is substantially equal to the length of the insertion pipe 44.

Next, the insertion pipe 44 is inserted through the joint pipe 45 into the hole 49 of the cylinder 43. In this case, the insertion is sufficiently performed until the insertion end of the insertion tube 44 contacts the bottom surface of the hole 49. By doing so, there is no gap between the cylinder 43 and the insertion tube 44, and it is possible to avoid the generation of turbulent flow of the refrigerant gas due to the rapid fluctuation of the flow path diameter, and to reduce the refrigeration function and generate abnormal noise. Can be prevented.

Then, as described above, the casing 46
Then, the connecting pipe 42 is pressed into the shaft hole of the insertion pipe 44 attached to the cylinder 43. Thus, by connecting the connection pipe 42 and the insertion pipe 44 by interference fit, the connection pipe 42 and the insertion pipe 44 are coaxially connected. In order to facilitate the press-fitting of the connecting pipe 42 into the inserting pipe 44, the inserting pipe 44 is formed of a copper alloy or the like with respect to the connecting pipe 42 made of stainless steel.

In this case, the joint pipe 45 is attached to the casing 46 before the cylinder 43 is assembled, so that the joint pipe 45 stands upright with respect to the casing 46. While the insertion pipe 44 and the coupling pipe 45 are connected by a clearance fit, the insertion pipe 44 and the cylinder 43 are connected by an interference fit to an intermediate fit. Therefore, by inserting the joint pipe 45 and the discharge hole 47 of the cylinder 43 coaxially when the cylinder 43 is mounted on the casing 46, the insertion pipe 44 inserted into the hole 49, the connecting pipe 42, and the discharge hole 47 are formed. Therefore, it is possible to prevent a decrease in the refrigerating function due to the misalignment.

In this manner, the insertion tube 44 is
4 until the outer end of 4 reaches the position of the outer end of the joint pipe 45.
, The outer ends of the insertion tube 44 and the joint tube 45 are welded to the side surface of the connection tube 42. The welding position in this case is a position sufficiently distant from the cylinder 43. Therefore, thermal distortion does not occur in the cylinder 43 due to welding heat. Also, by releasing the welding, the connecting pipe 42 is removed.
Can be easily removed from the compressor 41, and the compressor 4
Since the joint pipe 45 remains on the first side, the connecting pipe 4
When mounting 2 on the compressor 41, it can be mounted with high accuracy. That is, according to the present embodiment,
Maintainability can be improved.

As described above, in the present embodiment,
Prior to assembling the cylinder 43 into the casing 46, a hole 48 is formed at a position of the casing 46 where the discharge hole 47 of the cylinder 43 is to be located.
Insert the tip of and weld. Further, a hole 49 is formed in the opening of the discharge hole 47 of the cylinder 43 coaxially with the discharge hole 47 to form the intaglio portion. The joint pipe 45 and the discharge hole 4 are provided in a casing 46 to which the joint pipe 45 is attached.
The insertion tube 44 is inserted into the hole 4 of the cylinder 43 so that the cylinder 43 is coaxial.
9 is inserted into the hole 49 until it contacts the bottom surface. After that, the connection pipe 42 is pressed into the shaft hole of the insertion pipe 44,
The outer ends of the insertion tube 44 and the joint tube 45 are welded to the connection tube 42.

As described above, welding when connecting the connecting pipe 42 to the casing 46 of the compressor 41 is performed by the cylinder 43.
Is performed before being assembled, or at a position sufficiently distant from the cylinder 43. Therefore, cylinder 4
No thermal distortion occurs in 3.

The insertion tube 44 is inserted into the hole 49 until the insertion end of the insertion tube 44 contacts the bottom of the hole 49 of the cylinder 43.
Is inserted into. Therefore, the cylinder 43 and the insertion tube 4
No turbulent flow of the refrigerant gas can be prevented without generating a gap between the refrigeration gas and the refrigeration capacity 4, and generation of abnormal noise can be prevented. Further, the connection pipe 42 and the insertion pipe 44 are connected by an interference fit, and the insertion pipe 44 and the cylinder 43 are tightly fitted to each other.
Connect with an intermediate fit. Therefore, there is no misalignment in the connecting pipe 42, the insertion pipe 44, and the discharge hole 47, and it is possible to prevent a decrease in the refrigerating function due to the misalignment. The cylinder 43 is provided with a stamp portion (hole 49) so that the insertion tube 44 into which the connecting pipe 42 is press-fitted is fitted into the stamp portion. Accordingly, a gap is formed between the connecting pipe 42 and the cylinder 43 as in the conventional connecting portion shown in FIG. 4, and the refrigerant gas does not leak from the gap. That is, it is possible to prevent a decrease in refrigerant capacity by eliminating leakage loss. Further, the number of parts can be reduced as compared with the conventional connecting portion shown in FIG.

In the above embodiment, the discharge holes 47
However, it is needless to say that the present invention can also be applied to a series of compressors, although the example has a double compressor 41 having a substantially symmetrical structure with a plane including the axis as a boundary.

[0033]

As is apparent from the above description, the Stirling refrigerator according to the first aspect of the present invention has a joint pipe connecting the compressor and the expander with a joint pipe having a distal end. Welding to the casing of the compressor, forming an intaglio portion at the opening of the discharge hole in the cylinder of the compressor, inserting an insertion pipe through the joint pipe and into the intaglio portion of the cylinder, Since it is press-fitted into the insertion pipe and welded to the outer end of the insertion pipe and the outer end of the joint pipe, the welding is
This is performed before the cylinder is assembled in the casing or at a position away from the cylinder. Therefore, welding heat is not transmitted to the cylinder, and no thermal distortion occurs in the cylinder.

Further, the connecting pipe is press-fitted into the insertion pipe,
Since the insertion tube is inserted into the seal portion of the cylinder, no misalignment occurs in the connection tube, the insertion tube, and the discharge hole. Therefore, the refrigerating capacity does not decrease due to the misalignment of each tube or hole. Further, since the insertion pipe into which the connection pipe has been press-fitted is inserted into the seal portion of the cylinder, there is no gap between the connection pipe and the cylinder. Therefore, the refrigerant gas does not leak, and the refrigeration capacity does not decrease due to the gas leak.

In the Stirling refrigerator according to the second aspect of the present invention, since the insertion end of the insertion tube is in contact with the bottom surface of the intaglio portion, the insertion end of the insertion tube and the bottom surface of the intaglio portion are not in contact with each other. There is no gap between them. Therefore, the refrigerant gas discharged from the discharge hole of the cylinder becomes turbulent due to a sudden change in the flow path diameter, and does not generate abnormal noise or decrease the refrigerating capacity.

[Brief description of the drawings]

FIG. 1 is an enlarged sectional view of a connecting portion between a compressor and a connecting pipe in a Stirling refrigerator of the present invention.

FIG. 2 is an explanatory diagram of a connecting procedure by a connecting unit shown in FIG. 1;

FIG. 3 is a schematic sectional view of a Stirling refrigerator.

FIG. 4 is an enlarged sectional view of a conventional connecting portion between the compressor and the connecting pipe in FIG. 3;

FIG. 5 is an enlarged sectional view of a conventional connecting portion different from FIG.

FIG. 6 is an enlarged sectional view of a conventional connecting portion different from FIGS. 4 and 5;

[Explanation of symbols]

41: compressor, 42: connecting pipe, 4
3 ... cylinder, 44 ... insertion tube, 45
... joint pipe, 46 ... casing, 4
7 ... discharge holes, 49 ... holes.

Claims (2)

[Claims] 1. A compressor (41), and an expander that expands refrigerant gas from the compressor (41) to cool it to an extremely low temperature,
In a Stirling refrigerator having a connecting pipe (42) for connecting the compressor (41) and an expander, a hole provided in a casing (46) of the compressor (41) is provided.
A joint pipe (45) connected to the casing (46) and connected to the casing (46), and a cylinder (4) incorporated in the casing (46).
The above-mentioned discharge hole is provided in the opening of the refrigerant gas discharge hole (47) of 3).
(47), and an intaglio portion (49) formed coaxially with the (47);
9) having an insertion pipe (44) inserted therein, and the connecting pipe (42) being press-fitted into the outer end of the insertion pipe (44), and the outer end of the insertion pipe (44) and a joint. Tube (4
5) A Stirling refrigerator which is welded to an outer end. 2. The Stirling refrigerator according to claim 1, wherein an insertion end of the insertion tube (44) into the intaglio portion (49) is in contact with a bottom surface of the intaglio portion (49). Characteristic Stirling refrigerator.