JPH0593554A - Stirling freezer - Google Patents

Abstract

PURPOSE:To provide a Stirling freezer in which a wear at a seal part is reduced and its life is long. CONSTITUTION:In a Sterling freezer in which cold heat is generated under a reciprocating movement of a displacer 4 in response to a variation in pressure generated by a compressor cylinder 1 and in which a cold finer 3 and the cylinder 3 are communicated with a communication pipe 5, it has a displacer bearing 31, a displacer seal cylinder 33 movable in a radial direction so as to constitute a clearance seal 16, a piston bearing 32 and a piston seal cylinder 36 movable in a radial direction to constitute a clearance seal part 14. Accordingly, it does not accept any force in a radial direction acting against the displacer and the clearance seal part of the compressor piston, resulting in that wear at the seal part is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a Stirling refrigerator used for cooling infrared devices, liquefying air, and the like.

[0002]

2. Description of the Related Art FIG. 5 is a side sectional view showing a schematic structure of a conventional Stirling refrigerator disclosed in, for example, Japanese Patent Publication No. 1-281374. In the figure, 1 is a compressor cylinder, 2 is a piston that reciprocates vertically inside the compressor cylinder 1, 3 is a cold finger provided on the top of the compressor cylinder 1, and 4 is a cold finger 3.
A displacer that reciprocates due to a change in the pressure of the working gas inside, a communication pipe that communicates the cold finger 3 with the compressor cylinder 1, an expansion space 6 formed above the cold finger 3, and a cold finger 3 Is a first compression space formed in the lower part of the compressor cylinder, and 8 is a second compression space formed in the upper part of the compressor cylinder 1.

Reference numeral 9 is a heat accumulator provided in the displacer 4, through which the working gas flows, and 10 is a heat accumulator 9 and the first compression space 7.
Is a center hole of the displacer 4, and 11 and 12 are a center hole and a radial distribution duct which are provided in the upper operation part 4a of the displacer 4 and which communicate the heat storage unit 9 and the expansion space 6. The expansion space 6 and the radial distribution duct 1
2, the central hole 11, the heat accumulator 9, the central hole 10, the first compression space 7, the communication pipe 5 and the second compression space 8 form an operating space, and the operating gas is filled in the operating space.

Reference numeral 13 denotes a freezer as a heat exchanger composed of a portion including the expansion space 6 above the cold finger 3. The cold working gas expanded in the expansion space 6 and an external object to be cooled (not shown). Exchange heat with. Reference numeral 14 is a clearance seal portion formed between the piston 2 and the wall of the compressor cylinder 1, and 15 is a buffer space formed below the piston 2 of the compressor cylinder 1.
4 prevents the flow of working gas between the buffer space 15 and the working space. Reference numeral 16 is a clearance seal portion formed between the displacer 4 and the cold finger 3 so that the flow of the working gas between the expansion space 6 and the first compression space 7 is forced to flow in the heat accumulator 9. There is.

Reference numeral 17 denotes a lightweight sleeve provided in the buffer space 15 below the compressor piston 2 and made of a non-magnetic and non-magnetizable material such as aluminum, 18 denotes a coil formed by winding a conductor around the sleeve 17, 19, 20 is a coil 1
8, lead wires 21 and 22 led out through the wall of the compressor cylinder 1, electrical terminals for connecting the lead wires 19 and 20 to the outside of the compressor cylinder 1, and 23, a sleeve 17 and a coil 18 reciprocate in the vertical direction. It is a moving annular gap.

Reference numeral 24 is an annular permanent magnet having upper and lower magnetic poles,
Reference numeral 25 is a soft iron annular disk provided above the annular permanent magnet 24 and having the annular gap 23, and 26 is the annular permanent magnet 2.
4 and the soft iron annular disk 25, a soft iron cylinder disposed in the center of the disk 25, and 27 is a soft iron circular disk provided at the bottom of the compressor cylinder 1. The annular permanent magnet 24, the soft iron annular disk 25, the soft iron cylinder 26, and the soft iron circular disk 27 integrally form a closed magnetic circuit.

28 is the sleeve 17 and the coil 1 described above.
This is a linear motor for driving a piston which is wholly composed of 8, lead wires 19 and 20, an annular gap 23, an annular permanent magnet 24, a soft iron annular disc 25, a soft iron cylinder 26, a soft iron circular disc 27 and the like. 29 and 30 are elastic members for pistons and elastic members for displacers, respectively. By supporting the compressor piston 2 and the displacer 4 in the compressor cylinder 1 and the cold finger 3 so as to be reciprocally movable, the piston 2 and the displacer 4 are supported. The fixed position when the vehicle is stationary and the neutral position when the vehicle is operating are defined.

Next, the operation will be described. Electric terminal 2
When an alternating current power supply (not shown) having the same resonance frequency as the system is connected to 1 and 22, an alternating current in the circumferential direction flows through the coil 18, and the alternating current and the radial magnetic field created by the annular permanent magnet 24 interact with each other. Due to the action, a periodic Lorentz force acts on the coil 18 in the axial direction. As a result, the piston 2,
The system including the assembly including the sleeve 17 and the annular permanent magnet 24 and the piston elastic member 29 is in a resonance state, and the assembly vibrates in the axial direction.

The vibration of the piston 2 is transmitted from the expansion space 6, the first compression space 7, the second compression space 8, the communication pipe 5, the heat storage device 9, the central hole 10, the central hole 11, the radial flow duct 12 and the freezer 13. The working gas enclosed in the working space is caused to undergo a periodic pressure change, and the displacer 4 is caused to undergo a periodical alternating oscillating force due to a change in the flow rate of the gas passing through the heat accumulator 9. In this way, the displacer 4 including the heat accumulator 9 reciprocates axially in the cold finger 3 at the same frequency as the piston 2 but at different phases.

When the piston 2 and the displacer 4 move while maintaining an appropriate phase difference, the working gas enclosed in the working space constitutes a thermodynamic cycle known as the "reverse Stirling cycle", and mainly the expansion space. 6 and the freezer 13 generate cold heat. Regarding the above-mentioned "reverse Stirling cycle" and the principle of cold heat generation, see "C.
Ryocoolers "(G. Walker, Plen
um Press, New York, 1983, p.
p. 177-123).

The principle will be briefly described below. The working gas in the second compression space 8 compressed by the piston 2 has its compression heat cooled while flowing through the communication pipe 5, and flows into the first compression space 7, the central hole 10, and the heat accumulator 9. The working gas pre-cooled by the cold heat stored in the heat storage device 9 half a cycle before further passes through the central hole 11, the radial flow duct 12, and the freezer 13 to expand the expansion space 6
Enter inside. Then, when most of the working gas enters the expansion space 6, expansion starts and cold heat is generated in the expansion space 6. The working gas then returns through the flow path in the reverse order while releasing cold heat to the heat storage device 9 and enters the second compression space 8. At this time,
Heat is taken from the outside in the freezer 13 to cool the outside. Then, when most of the working gas returns to the second compression space 8, the compression starts again, and the next cycle starts. By the process as described above, the "reverse Stirling cycle" is completed and cold heat is generated.

[0012]

Since the conventional Stirling refrigerator is constructed as described above, the displacer 4 moves in the radial direction due to its own weight, the eccentricity of the elastic member 30 for the displacer, and the like of the cold finger 3. It contacts the inner surface and reciprocates. Therefore, the displacer 4
When the cold finger 3 is worn and the clearance of the clearance seal portion 16 is increased, and the working gas in the first compression space 7 flows into the expansion space 6, or conversely, the working gas in the expansion space 6 is transferred to the first compression space 7. When flowing, the working gas is regenerator 9
Since it flows through the clearance seal portion 16 without passing through, the part of the high temperature working gas in the first compression space 7 flows into the expansion space 6 without being pre-cooled in the heat storage device 9, or the low temperature operation of the expansion space 6 is performed. Since a part of the gas flows into the first compression space 7 without releasing cold heat in the heat storage device 9, there is a problem that the performance of the refrigerator is significantly reduced.

Further, the piston 2 moves in the radial direction due to its own weight, the eccentricity of the elastic member 29 for the piston, and the like, comes into contact with the inner surface of the compressor cylinder 1 and reciprocates. Therefore, the piston 2 and the compressor cylinder 1 are worn and the clearance of the clearance seal portion 14 is increased, and the working gas in the second compression space 8 flows into and out of the buffer space 15 through this clearance. There is a problem that the pressure change of the working gas becomes small and the performance of the refrigerator is significantly deteriorated.

The present invention has been made to solve the above problems, and an object of the invention is to obtain a Stirling refrigerator having a long life with less wear of the seal portion.

[0015]

According to a first aspect of the present invention, there is provided a Stirling refrigerator having a displacer bearing for preventing a cold finger from coming into contact with the displacer when the displacer reciprocates, and a displacer bearing housed in the cold finger for radial direction. And a displacer seal cylinder that is movable, and the inner peripheral surface of the displacer seal cylinder and the outer peripheral surface of the displacer constitute a clearance seal portion, and the upper end surface and the lower end surface of the displacer seal cylinder respectively contact the cold fingers. It is designed to seal the working gas.

According to a second aspect of the present invention, there is provided a Stirling refrigerator having a piston bearing which prevents the piston from coming into contact with the compressor cylinder when the piston reciprocates, and a piston which is housed in the compressor cylinder and is movable in the radial direction. A seal cylinder is provided, and a clearance seal portion is formed by the inner peripheral surface of the piston seal cylinder and the outer peripheral surface of the piston, and the upper end surface and the lower end surface of the piston seal cylinder come into contact with the compressor cylinder to generate a working gas. It is designed to be sealed.

[0017]

In the Stirling refrigerator according to the first aspect of the present invention, the displacer is supported by the displacer bearing, and therefore the displacer seal cylinder and the displacer forming the clearance seal part are operated with almost no contact. Very little wear. Furthermore, when the displacer bearing is worn, even if the displacer is eccentric, the displacer seal cylinder will be eccentric as well as the displacer.Therefore, the displacer seal cylinder and displacer that form the clearance seal part will not wear much and the clearance will not become large. ,
The performance of the Stirling refrigerator does not deteriorate.

In the Stirling refrigerator according to the second aspect of the invention, since the piston is supported by the piston bearing, the piston seal cylinder constituting the clearance seal portion and the piston are operated with almost no contact, and for this reason,
Very little wear on the seal. Further, even when the piston bearing is worn, even if the piston is eccentric, the piston seal cylinder is eccentric as well as the piston, so the piston seal cylinder and the piston that form the clearance seal are hardly worn, and the clearance does not become large. The performance of the Stirling refrigerator does not deteriorate.

[0019]

【Example】

Example 1. An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, parts corresponding to those in FIG. In FIG. 1, 31 is a displacer bearing fixed to the cold finger 3, 32 is a piston bearing fixed to the compressor cylinder 1, 33 is a displacer 4 and a clearance seal part 16, and is a displacer seal cylinder movable in the radial direction. , 34 are upper end surface seal portions of the displacer seal cylinder 33,
Reference numeral 35 denotes a lower end surface seal portion of the displacer seal cylinder 33, 36 denotes a piston 2 and a clearance seal portion 14, and a piston seal cylinder 37 movable in a radial direction, 37
Is the upper end face seal part of the piston seal cylinder 36,
Reference numeral 38 denotes a lower end surface seal portion of the piston seal cylinder 36.

Next, the operation will be described. 2 (a),
The operation of each seal portion of the displacer 4 is shown in (b).
FIG. 2A shows the displacer 4 moving upward in the cold finger 3. Working gas is heat storage 9
Since it flows downward in the inside, pressure loss occurs in the heat storage device 9,
The working gas pressure in the expansion space 6 becomes higher than that in the first compression space 7. At this time, the displacer seal cylinder 33 is pressed downward due to the pressure difference due to the above-mentioned pressure loss, and the working gas is filled with the clearance seal portion 16 and the displacer seal cylinder 3.
It is sealed by the lower end surface seal portion 35 of the No. 3 unit.

FIG. 2B shows when the displacer 4 moves downward in the cold finger 3. Since the working gas flows upward in the heat storage device 9, a pressure loss occurs in the heat storage device 9, and the working gas pressure in the expansion space 6 becomes lower than that in the first compression space 7. At this time, the displacer seal cylinder 33 is pressed upward due to the pressure difference due to the pressure loss, and the working gas is sealed by the clearance seal portion 16 and the upper end surface seal portion 34 of the displacer seal cylinder 33. At this time, the displacer 4 is displacer bearing 3
Since it is supported by No. 1, almost no force acts in the radial direction on the displacer seal cylinder 33 forming the clearance seal portion 16, and therefore the clearance seal portion 16 is not worn.

The operation of each seal portion of the piston 2 is shown in FIGS. FIG. 3A shows the time when the piston 2 moves upward in the compressor cylinder 1. The pressure of the working gas in the working space rises, and the working gas pressure in the second compression space 8 becomes higher than the gas pressure in the buffer space 15. At this time, the piston seal cylinder 36 is pressed downward due to the above pressure difference, and the working gas is sealed by the clearance seal portion 14 and the lower end surface seal portion 38 of the piston seal cylinder 36.

FIG. 3B shows when the piston 2 moves downward in the compressor cylinder 1. The pressure of the working gas in the working space decreases, and the working gas pressure in the second compression space 8 becomes lower than the gas pressure in the buffer space 15. At this time, the piston seal cylinder 36 is pressed upward by the pressure difference, and the working gas is sealed by the clearance seal portion 14 and the upper end surface seal portion 37 of the piston seal cylinder 36. At this time, since the piston 2 is supported by the piston bearing 32, almost no force acts in the radial direction on the piston seal cylinder 36 forming the clearance seal portion 14, and therefore the seal portion does not wear.

According to the Stirling refrigerator shown in the first embodiment, the freezer 13 operates in exactly the same manner as the conventional example.
Similarly, cold heat is generated in the expansion space 6, and the performance can be maintained for a long time.

Since the operating principle of the Stirling refrigerator shown in the first embodiment is exactly the same as that of the conventional example, its explanation is omitted here.

Example 2. In the first embodiment described above, the case in which the cold finger 3 and the compressor cylinder 1 are mechanically strongly coupled to each other has been described as an integral type refrigerator, but as in another embodiment of the present invention shown in FIG. In addition, the cold finger 3 and the compressor cylinder 1 may be a separate type refrigerator in which the cold finger 3 and the compressor cylinder 1 are separated from each other through the communication pipe 5, and the same effect as that of the first embodiment is obtained.

[0027]

As described above, according to the first aspect of the present invention, the displacer bearing for preventing the displacer from coming into contact with the cold finger when reciprocating, and the displacer bearing housed in the cold finger and movable in the radial direction. A displacer seal cylinder, the inner peripheral surface of the displacer seal cylinder and the outer peripheral surface of the displacer constitute a clearance seal portion, and the upper end surface and the lower end surface of the displacer seal cylinder come into contact with the cold fingers to operate. Since it is configured to perform gas sealing, the displacer is supported by the displacer bearing, so the displacer seal cylinder and the displacer that form the clearance seal part are operated with almost no contact, and therefore wear of the seal part is prevented. Very few. Furthermore, when the displacer bearing is worn, even if the displacer is eccentric, the displacer seal cylinder is eccentric as well as the displacer.Therefore, the displacer seal cylinder and displacer that form the clearance seal part are hardly worn, and therefore the clearance is large. As a result, the performance of the Stirling refrigerator is not deteriorated and a long life can be obtained.

According to the invention of claim 2, a piston bearing for preventing the piston from coming into contact with the compressor cylinder when the piston reciprocates, and is housed in the compressor cylinder.
A piston seal cylinder movable in the radial direction is provided, and a clearance seal portion is constituted by the inner peripheral surface of the piston seal cylinder and the outer peripheral surface of the piston, and the compressor cylinder is constituted by the upper end surface and the lower end surface of the piston seal cylinder, respectively. Since the piston is supported by the piston bearing because the working gas is sealed by contacting with the piston, the piston seal cylinder forming the clearance seal part and the piston are operated with almost no contact. Very little wear on the seal. Further, even if the piston bearing is worn, even if the piston is eccentric, the piston seal cylinder is eccentric as well as the piston, so the piston seal cylinder and the piston that form the clearance seal part are hardly worn, and therefore the clearance is also large. In addition, the performance of the Stirling refrigerator is not deteriorated, and the effect of extending the life can be obtained.

[Brief description of drawings]

FIG. 1 is a side sectional view showing a Stirling refrigerator according to an embodiment of the present invention.

FIG. 2 is a side sectional view of an essential part showing the operation of the Stirling refrigerator according to the embodiment of the present invention.

FIG. 3 is a side sectional view of an essential part showing another operation of the Stirling refrigerator according to the embodiment of the present invention.

FIG. 4 is a side sectional view of a Stirling refrigerator showing another embodiment of the present invention.

FIG. 5 is a side sectional view showing a conventional Stirling refrigerator.

[Explanation of symbols]

 1 Compressor Cylinder 2 Piston 3 Cold Finger 4 Displacer 8 Second Compression Space (Compression Space) 9 Heat Storage 14, 16 Clearance Seal Part 31 Displacer Bearing 32 Piston Bearing 33 Displacer Seal Cylinder 36 Piston Seal Cylinder

Claims (2)

[Claims] 1. A displacer having a built-in heat accumulator is provided reciprocally in the cold finger, the compressor cylinder having a piston and a cold finger communicating with the compression space of the compressor cylinder. The
In a Stirling refrigerator in which a working space is formed by the compression space, the internal space of the cold finger, and the heat accumulator, and the working gas is enclosed in the working space, the cold finger is not contacted when the displacer reciprocates. And a displacer bearing for moving the movable body in a direction orthogonal to the reciprocating direction of the displacer and forming a clearance seal between the displacer bearing and the displacer and both end faces in the reciprocating direction. And a displacer seal cylinder for contacting the cold finger to seal the working gas. 2. A compressor cylinder provided with a piston, and a cold finger communicating with a compression space of the compressor cylinder, and a displacer having a built-in heat accumulator reciprocatingly provided inside the cold finger. The
In a Stirling refrigerator in which a working space is formed by the compression space, the internal space of the cold finger, and the heat accumulator, and working gas is filled in the working space, the piston contacts the compressor cylinder when the piston reciprocates. To prevent it from moving in a direction orthogonal to the reciprocating direction of the piston, which is housed in the compressor cylinder and forms a clearance seal between the piston and the reciprocating direction of the piston. A Stirling refrigerator, comprising: a piston seal cylinder that seals the working gas by contacting the compressor cylinder on both end faces.