JPH0334611Y2 - - Google Patents

Description

[Detailed explanation of the idea] [Technical field to which the idea belongs]

This invention relates to an inverted Stirling cycle refrigerator that uses a compressible gas as a working gas, and particularly to the structure of a heat dissipation section for the working gas.

[Prior art and its problems]

The reverse Stirling cycle is known as a refrigeration cycle that uses a compressible gas that does not easily change at low temperatures, such as helium, hydrogen, or nitrogen, as an operating gas, and the configuration of the refrigerator is shown in FIG. In Figure 1,
1 is a crank chamber; 2 is a crankshaft driven by a motor (not shown); a compression piston 5 and an expansion piston 6 are connected to the crankshaft via connecting rods 3 and 4; The pistons 5, 6 are inserted into a compression cylinder 7 and an expansion cylinder 8, respectively, which are integrally constructed in series with the crank chamber 1. Furthermore, a regenerator 9 made of a wire mesh or the like is integrally formed with the expansion piston 6, and one end of the regenerator 9 is connected to a gas passage 10 inside the piston.
The other end opens into the port 11 of the expansion cylinder 8 through the opening, and the other end opens into the cylinder chamber 80 of the expansion cylinder 8 . Furthermore, a pipe 13 is externally connected between the port 11 and the port 12 communicating with the cylinder chamber 70 of the compression cylinder 7, and a large number of heat radiation fins are brazed to the outer periphery of the pipe 13 in the middle. A heat radiator 14 is installed. Note that O is the rotation center of the crankshaft 2, and 15 is a seal member provided on the outer periphery of each piston. In addition, in the above configuration, the compression piston 5 and the expansion piston 6 are approximately
It is connected to the crankshaft 2 so that the pistons move with a phase difference of 90 degrees. Next, the operation of the reverse Stirling cycle with the above configuration will be explained using the configuration diagram of FIG. 1, the PV diagram of the reverse Stirling refrigeration cycle shown in FIG. 2, and the operation process diagram of FIG. 3. In Fig. 3, A and B indicate the compression piston, respectively.
In the movement trajectory of the expansion piston, the interval between lines A and B represents the volume change of the working gas.
As is well known, the reverse Stirling cycle theoretically consists of two isothermal strokes and two isovolumic strokes. (See Figure 2) The expansion piston 6 is now at the center of its reciprocating stroke, and when the compression piston 5 begins to move from the bottom dead center with a 90° phase delay, the working gas sealed in the compression cylinder 7 is compressed. The compression heat generated at this time is released to the outside by the radiator 14, so the gas in the port 11 becomes gas at room temperature and high pressure, and as shown in Fig. 2 →
Isothermal compression shown in is performed. Next, when the compression piston 5 is further moved toward the top dead center while lowering the expansion piston 6, the working gas radiates heat to the regenerator 9 inside the expansion piston and enters the cylinder space 80 of the expansion cylinder 8, which is called a volumetric volume. becomes a constant isovolumic heat dissipation stroke (→ in Fig. 2). Next, when the expansion piston 6 is moved further downward, the gas that enters the cylinder chamber 80 undergoes an isothermal expansion stroke (isothermal expansion stroke) in which the gas enters the cylinder chamber 80 and expands while absorbing heat from an object to be cooled (not shown) through a cold station constructed at the top of the expansion cylinder. →) in Figure 2 and freezing occurs. Furthermore, by moving the expansion piston 6 toward the top dead center and the compression piston 5 toward the bottom dead center, the low-temperature operating gas absorbs heat from the regenerator 9 and gradually increases its temperature and pressure. Heat sink 14
One cycle is completed by following an isovolumic endothermic stroke (→ in FIG. 2) through which the compressor returns to the compression cylinder 7. The above is an explanation of the operation of the refrigeration cycle based on the reverse Stirling cycle. By the way, in a conventional refrigerator, the actual structure of the radiator 14 is as shown in FIG. 17 and 18 are brazed together and connected to ports 11 and 12 via a sealing member 19 such as an O-ring. However, since such a structure is adopted, there are the following problems. That is, since the radiator 14 is connected to the outside of the refrigerator body, the flange 1
Operating gas is likely to leak from 7 and 18. Moreover, if there is a leak of operating gas, the pressure inside the system will drop,
The specified refrigeration performance cannot be maintained. Furthermore, since the pipe 13 of the radiator 14 is a pipe with a circular cross section, the ratio of the circumferential length to the cross-sectional area (circumferential length/cross-sectional area) is small, making it difficult to obtain the inner surface area necessary to obtain the required heat radiation. This increases the pipe length and increases the pipe volume of the radiator. This increases dead volume, which reduces effective work and causes a reduction in refrigeration capacity. Furthermore, a small diameter pipe 13
Since the fins 16 are brazed to the fins 16, manufacturing is troublesome, and since the radiator 14 is connected to the outside of the refrigerator body, this becomes an obstacle to miniaturization.

[Purpose of invention]

This invention solves the problems in the conventional technology, and is an inverted Stirling ring with a built-in heat dissipation part that has no external leakage of operating gas, has a small dead volume in the heat dissipation part, is easy to manufacture, and has a compact configuration. The purpose is to provide cycle refrigerators.

[Key points of the idea]

In order to achieve the above objective, this idea was designed to be built into the refrigerator body, whereas conventional heat radiators are externally mounted. In the refrigerator, the refrigerator has a compression cylinder and an expansion cylinder that communicate with each other, and performs a reverse Stirling cycle between the compression cylinder and the expansion cylinder by reciprocating a piston using a compressible gas as a working gas. A plurality of circumferential grooves each having a rectangular cross section and arranged in parallel along the axial direction of the cylinder body are provided on the inner circumferential surface of the cylinder body, and a cylinder bush is provided in the cavity of the cylinder body. The cylinder bush is fitted on the outer circumferential surface opposite to the circumferential groove provided on the inner circumferential surface of the cylinder body cavity, and extends between the circumferential grooves in the axial direction of the cylinder body, and the cylinder bush is fed from the compression cylinder. The header groove has a header groove that distributes the working gas that has been flowing into each of the circumferential grooves, and the header groove is composed of a first header groove, a second header groove, and a third header groove, and the header groove is composed of a first header groove, a second header groove, and a third header groove. The header groove extends between all of the circumferential grooves, and the second header groove and the third header groove are approximately connected to the first header groove.
The header groove is divided into two parts in the axial direction on the circumference separated by 180 degrees, and is located so as to straddle between the circumferential grooves, the second header groove communicates with the inside of the compression cylinder, and the third header groove A built-in type refrigerator communicating with the expansion cylinder via a gas passage bored in the refrigerator main body, and having the circumferential groove and the header groove interposed in the gas passage between the compression cylinder and the expansion cylinder. The heat dissipating section is configured to dissipate the heat of the working gas by dispersing the working gas into each groove of the heat dissipating section during operation.

[Example of idea]

Next, an embodiment of this invention will be described with reference to FIGS. 5 to 8. In the figure, the compression cylinder 7 is a cylinder body 7 integrally constructed with the crankcase 1.
1. It is an assembly including a cylinder cover 72, a cylinder bush 73, etc., which is tightly fitted into the cavity of the cylinder body 71 by a shrink fit method. The cylinder body 71 and the cylinder cover 72 have heat radiation fins 74 on their outer peripheries, and seal members 75 such as O-rings are provided between the cylinder body 71 and the cylinder bush 73 and between the cylinder cover 72.
Further, the cylinder cover 72 is fastened to the end surface of the cylinder body 71 via bolts 76. The compression cylinder 7 has a plurality of concave circumferential grooves 80 arranged in parallel along the axial direction on the inner circumferential surface of the cylinder body 71, and a cylinder facing each circumferential groove 80. On the outer peripheral surface of the bush 73,
Axial header grooves 81 and 8 spanning the circumferential groove 80
2,83 are formed. Of these, header 81
and 83 are inlet and outlet header grooves formed approximately in halves in the axial direction with matching phases in the circumferential direction.
On the other hand, the header groove 82 is
It is located on the circumference on the opposite side 180 degrees apart from No. 3, and both ends in the axial direction are closed. The aforementioned grooves 80, 81, 82, and 83 constitute a heat dissipation section 84 built into the main body. The starting end of the header groove 81 communicates with the cylinder space 70 through a radial gas passage 85 cut out in the edge of the cylinder bush 73, and the terminal end of the header groove 83 is bored inside the cylinder body 71. It communicates with the expansion cylinder 8 through a gas passage 77 . Here, the groove path of the heat dissipating portion 84 is expanded and drawn for ease of understanding as shown in FIG. 8. Next, the heat dissipation operation of the built-in heat dissipation section 84 having the above structure will be described. In FIG. 6, when the piston 5 moves to the left, the working gas in the cylinder chamber 70 is compressed and flows from there through the heat radiation part 84 toward the expansion cylinder. That is, the compressed high-temperature gas is first introduced from the compression cylinder chamber 70 through the gas flow path 85 into the header groove 81, and from there it is divided into the front half area of the circumferential groove 80 lined up on the inner circumferential surface of the cylinder body, and is then distributed around the circumference. It flows through the groove toward the intermediate header groove 82. The gases that have merged in the header groove 82 flow in the axial direction in the header groove 82 , branch from there to the remaining latter half of the circumferential groove 80 , and then merge into the header groove 83 . In this process, the working gas flowing into the circumferential groove 80 undergoes heat transfer with the wall surface of the cylinder body 71, and is radiated into the atmosphere through the heat radiation fins 74 of the cylinder body 71. As a result, the working gas is cooled to room temperature. will be fed through passage 77 towards the expansion cylinder. At this time, in this invention, the first
A header groove 82, a second header groove 81, and a third header groove 83 are provided. Therefore, the flow of the operating gas bends at the dividing point between the second header groove 81 and the circumferential groove 80 and the confluence point between the third header groove 83 and the circumferential groove 80, and The flow from the second header groove 81 collides with the portion indicated by the large rectangle in the center of the figure. As a result, vortices are generated in the flow of the working gas. The generation of this vortex increases the chance of contact between the side surface of the circumferential groove 80 and the working gas, increases the amount of heat transferred to the cylinder body 71, and makes it easier to cool the working gas. Note that the heat generated in the cylinder bush 73 is transferred to the heat radiation fin 74 through the contact surface between the cylinder bush and the cylinder body.
More heat is dissipated to the outside. Each of the grooves constituting the heat dissipation section 84 mentioned above is formed so that its cross-sectional shape is a concave groove with a rectangular cross section. The reason for this is that by increasing the ratio of the peripheral length and cross-sectional area (perimeter/cross-sectional area) of the cross-section of the channel in the groove as much as possible, the heat dissipation area per unit volume of the channel can be increased, and the required heat dissipation capacity can be increased. This is to reduce the dead volume of the working gas and fluid resistance by shortening the length of the pipe line required to obtain the groove, and to facilitate the cutting process of the groove.

[Effect of the idea]

As described above, according to this invention, the refrigerator main body has a compression cylinder and an expansion cylinder that communicate with each other via a heat radiating part and a regenerator, and the reciprocating movement of the piston uses compressible gas as a working gas to connect the compression cylinder to the compression cylinder. In a refrigerator that performs a reverse Stirling cycle between the compression cylinder and the expansion cylinder, a plurality of concave grooves each having a rectangular cross section are formed on the inner circumferential surface of the cylinder body of the compression cylinder and extend in the axial direction of the cylinder body. circumferential grooves are provided in parallel with each other, and a cylinder bushing is fitted into the cavity of the cylinder body, and the cylinder bush is disposed on an outer circumferential surface opposite to the circumferential groove provided on the inner circumferential surface of the cylinder body cavity. A header groove is provided between the circumferential grooves and extends in the axial direction of the cylinder body and distributes the working gas sent from the compression cylinder to each of the circumferential grooves, and the header groove includes:
It consists of a first header groove, a second header groove, and a third header groove, the first header groove straddling all of the circumferential grooves, and the second header groove, the third header groove The header groove is divided into two parts in the axial direction on a circumference separated by approximately 180 degrees from the first header groove, and is located astride between the circumferential grooves, and the second header groove is located within the compression cylinder. The third header groove communicates with the expansion cylinder via a gas passage bored in the refrigerator main body, and the third header groove communicates with the expansion cylinder through a gas flow path bored in the refrigerator body, and connects the circumferential groove and the header groove between the compression cylinder and the expansion cylinder. A built-in heat dissipation section is provided in the gas passage between the two, and the operating gas is distributively flowed into each groove of the heat dissipation section during operation to dissipate the heat of the operating gas, resulting in the following effects. play. A refrigeration cycle can be performed between the compression cylinder and expansion cylinder without the risk of operating gas leaking to the outside. Since the heat dissipation section for the operating gas is built into the compression cylinder, it is possible to downsize the entire refrigerator. By using a header groove, vortices are generated in the flow of the operating gas, which can significantly improve the cooling characteristics of the operating gas. By making the cross-sectional shape of the circumferential groove rectangular, the heat dissipation area per unit volume of the flow path is increased, and the pipe length required to obtain the required heat dissipation capacity is shortened, reducing the dead volume of the working gas and fluid resistance. It is possible to reduce Since the circumferential groove is formed as multiple independent grooves with a rectangular cross section, processing time and costs can be reduced compared to, for example, forming multiple spiral grooves. One end of the heat dissipation part communicates with the expansion cylinder through a passage formed in the refrigerator body, making it possible to further downsize the entire refrigerator.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of a conventional reverse Stirling cycle refrigerator, and FIGS. 2 and 3 are a pressure-specific volume diagram and a diagram of the operating process principle of the refrigerating cycle, respectively, showing a reverse Stirling cycle refrigeration cycle. 4 is a block diagram of the radiator shown in FIG. 1, FIG. 5 is a sectional view of the structure of an embodiment of this invention, FIG. 6 is an enlarged sectional view of the compression cylinder in FIG. 5, and FIG. 8 is a cross-sectional view taken in the direction of the arrows, and FIG. 8 is a developed view of the groove path of the heat dissipation part. 5... Compression piston, 6... Expansion piston, 7
... Compression cylinder, 8 ... Expansion cylinder, 9 ...
Regenerator, 71... Cylinder body, 72... Cylinder cover, 73... Cylinder bush, 77... Gas flow path, 80... Circumferential groove, 81... Second header groove, 82... First Header groove, 83... Third header groove, 84... Heat radiation section, 85... Gas flow path.

Claims (1)

[Scope of utility model registration request] The refrigerator main body has a compression cylinder and an expansion cylinder that communicate with each other via a heat radiating part and a regenerator, and a reverse star ring is generated between the compression cylinder and the expansion cylinder by the reciprocating movement of a piston using a compressible gas as a working gas. In a refrigerator that performs a cycle,
A plurality of circumferential grooves each having a rectangular cross section and arranged in parallel along the axial direction of the cylinder body are provided on the inner circumferential surface of the cylinder body of the compression cylinder, and further within the cavity of the cylinder body, A cylinder bush is fitted, and the cylinder bush extends between the circumferential grooves in the axial direction of the cylinder body on the outer circumferential surface opposite to the circumferential groove provided on the inner circumferential surface of the cylinder body cavity. It has a header groove that distributes the working gas sent from the compression cylinder to each of the circumferential grooves,
The header groove includes a first header groove, a second header groove, and a third header groove, the first header groove straddling all of the circumferential grooves, and the second header groove straddling the circumferential grooves. , the third header groove is divided into two in the axial direction on a circumference separated by approximately 180 degrees from the first header groove, and is located astride between the circumferential grooves; communicates with the compression cylinder,
The third header groove communicates with the expansion cylinder via a gas passage bored in the refrigerator main body, and the circumferential groove and the header groove are connected to the gas passage between the compression cylinder and the expansion cylinder. A refrigerator having a built-in heat dissipation section interposed in the main body, and configured to dissipate the heat of the operating gas by distributing and flowing the operating gas into each groove of the heat dissipation section during operation.