JP2003294330A - Stirling refrigerator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently house a heat accumulating material 176 in an inside space of an expansion piston 93, and to regulate its movement. <P>SOLUTION: The expansion piston 93 is formed of an upper expansion piston 93a internally provided with the heat accumulating material 176, and a lower expansion piston 93b for engaging with the upper expansion piston 93a. A lower end part of the upper expansion piston 93a is inserted inside the lower expansion piston 93b. The lower end part of the upper expansion piston 93a and a bottom surface of the lower expansion piston 93b engage by abutting or almost abutting. A heat accumulating material support ring 112 for supporting the heat accumulating material 176 is installed on an inner cylinder surface in the vicinity of both openings in the upper expansion piston 93a, and the heat accumulating material 176 is sandwiched and supported by the two heat accumulating material support rings 112. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a Stirling refrigerator which can efficiently store heat of working gas.

[0002]

2. Description of the Related Art Stirling refrigerators can be miniaturized,
High coefficient of performance and high refrigeration efficiency, wide temperature range generated,
It has many excellent features such as easy replacement of CFCs in recent global environmental problems.

For this reason, commercial or domestic cold heat utilization equipment such as freezers, refrigerators, and throw-in coolers, low-temperature liquid circulators, low-temperature incubators, constant-temperature baths, heat shock test equipment, freeze dryers, temperature characteristics Application to cold heat utilization equipment in all industrial fields such as test equipment, blood / cell storage equipment, cold cooler, and various other heat and cold equipment is being studied.

Such a Stirling refrigerator has a compression piston that reciprocates in a compression cylinder to compress a working gas in a compression space, and an expansion piston that reciprocates in an expansion cylinder to expand a working gas in an expansion space. A gas flow path that connects the compression space and the expansion space to allow working gas to flow between them, and a heat storage material that is provided in the gas flow path and that stores the heat of the flowing working gas ing.

In such a structure, there is known a structure in which the inside of the expansion piston is used as a cavity and this internal space is used as a gas flow path, and a heat storage material is housed in the internal space to downsize the device. ing.

In this case, since it is necessary to store the heat storage material in the expansion piston, the expansion piston 593 is divided into an upper expansion piston 594 and a lower expansion piston 595, as shown in FIGS. There is.

FIG. 5 is a view showing the structure of the upper expansion piston 594, FIG. 5 (a) is a top view, FIG. 5 (b) is a side sectional view, and FIG. 6 shows the structure of the lower expansion piston 595. 6A is a top view and FIG. 6B is a side sectional view.

Further, FIG. 7 shows these upper expansion pistons 59.
4 shows a cross-sectional view of the assembled No. 4 and the lower expansion piston 595.

As can be seen from these figures, the expansion piston 5
A plurality of holes 610 are provided on the cylinder head surface on the expansion space side of 93.
And the expansion piston 59 is formed through this hole 610.
The inside of 3 and the expansion space communicate with each other.

A hole is also provided in the lower portion of the lower expansion piston 595 so that the inside of the lower expansion piston 595 and the compression space communicate with each other.

The upper expansion piston 594 and the lower expansion piston 595 contain a heat storage material 676, respectively.

[0012]

However, in the above structure, the upper expansion piston 594 and the lower expansion piston 5 are arranged.
Since the heat storage material 676 is housed in each of 95 and 95, a large space S as shown in FIG. 7 is generated when these are assembled, and the heat storage material 676 is efficiently stored in the internal space of the expansion piston 593. There was a problem that it was difficult to store and it was difficult to improve the refrigeration efficiency.

Further, since the heat storage material 676 is not fixed in the expansion piston, the heat storage material 676 also moves due to the reciprocating motion of the expansion piston, and there is a problem that abrasion powder is generated or damaged due to friction. It was

Therefore, the present invention provides a Stirling refrigerator in which the heat storage material can be efficiently stored in the internal space of the expansion piston, and its movement is restricted to improve the refrigeration efficiency and reliability. The purpose is to do.

[0015]

In order to solve the above problems, the invention according to claim 1 provides a compression piston for compressing a working gas in a compression space, an expansion piston for expanding a working gas in an expansion space, and a working gas. Stirling refrigerator provided with a gas flow path that allows the air to move between the expansion space and the compression space, and a heat storage material that stores the heat of the working gas that travels between the expansion space and the compression space via the gas flow path. At
The expansion piston is formed from an upper expansion piston having a heat storage material provided therein and a lower expansion piston that engages with the upper expansion piston, and the lower end of the upper expansion piston is inserted inside the lower expansion piston. It is characterized in that the lower end portion of the upper expansion piston and the bottom surface of the lower expansion piston abut or substantially abut and engage with each other.

The invention according to claim 2 is characterized in that the upper expansion piston is formed by a tubular member, and both ends thereof are opened.

According to the third aspect of the present invention, the heat storage material support ring for supporting the heat storage material inside the upper expansion piston is mounted on the inner cylindrical surface near both openings of the upper expansion piston. It is characterized in that the heat storage material is sandwiched and supported by the heat storage material support ring.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a side cross-sectional view of a Stirling refrigerator applied to the description of the present embodiment. The Stirling refrigerator mainly includes a cold heat generating unit that generates cold heat and a driving device that drives the cold heat generating unit. .

The drive unit 11 has a motor housing 12 having a motor chamber 13 inside, and a motor 14 composed of a stator 15 and a rotor 16 capable of rotating in the forward and reverse directions is installed in the motor chamber 13. It is output via the shaft 17.

The cold heat generating section 33 includes a power converting section 34 for converting the rotational power generated by the drive unit 11 into reciprocating power, a compressing section 64 for compressing the working gas, an expanding section 90 for expanding the working gas, and the expanding section 90. A cold head portion 219 that supplies cold heat generated by the expansion of the working gas to the cold heat utilization equipment, an oil seal portion 148 that prevents the oil 248 in the crank space 36 from entering the compression space 66 and the expansion space 92, and the like. is doing.

The power converter 34 has an internal crank space 3
6 has a crank housing 35, and the crank housing 35 is provided in contact with the motor housing 12 via the motor housing top 19.

At the bottom of the crank housing 35, oil 248 that lubricates the sliding portion of the power conversion unit 34 and the like.
Is stored, and the stored amount is a viewing window 50 made of a transparent member such as glass formed on the bottom side of the crank housing 35.
Can be confirmed by.

An oil passage hole 20 is formed on the bottom side of the motor housing top 19 to connect the motor chamber 13 and the crank space 36.

As a result, the oil 248 is also supplied to the motor chamber 13.
Is stored, and the motor chamber 13 and the crank space 36 are stored.
The atmosphere with can be exchanged with each other.

The motor housing 12 and the crank housing 35 are each sealed with a lid, and the motor housing 12, the crank housing 35 and the motor housing top 19 are manufactured by casting.

Therefore, the motor housing 12, the crank housing 35, and the motor housing top 19 can be cast as one body, and in this case, there is an advantage that the manufacturing cost can be reduced.

In such a Stirling refrigerator 1, it is possible to use helium, hydrogen, nitrogen, etc. as a working gas, and in this case, it is preferable to fill the crank space and the motor chamber.

This is to prevent a situation in which the atmosphere in the crank space and the motor chamber slightly intrudes into the compression space and the expansion space due to long-time operation, thereby lowering the refrigeration efficiency.

In the crank space 36, a crank shaft 37 connected to the motor shaft 17, a crank 38 mounted on the crank shaft 37, a connecting rod 41 having one end connected to the crank 38, and the other end of the connecting rod 41. A cross guide head 44 and the like connected to the are provided.

The compression-side crank 38 and the expansion-side crank 38 are provided eccentrically with respect to the axis of the crankshaft 37, and the expansion-side crank is the compression-side crank when the motor 14 rotates in the normal direction. It is provided so that the phase is rotated by about 90 degrees ahead of 38.

Here, the forward rotation of the motor 14 refers to the direction of rotation of the motor 14 during the cycle operation that produces cold heat.

At this time, the Stirling refrigerator 1 is provided with a balancer 51 in order to suppress the rotational imbalance caused by the phase difference between the expansion-side crank 38 and the compression-side crank 38.

A fixed plate 243 is provided on the crank housing 35, and a cylinder housing 74 is provided on the fixed plate 243.

The compression portion 64 is formed by making a hole in the cylinder housing 74 to form a compression cylinder 68 and a compression cylinder 6.
8, a reciprocating compression piston 67, one end of which is swingably attached to the cross guide head 44 and the other end of which is fixedly attached to the compression piston 67, and a piston rod 69 for connecting them, and a head of the compression piston 67. It has a compression space 66 formed by the side and the compression cylinder 68.

A compression piston ring 70 is mounted on the side cylindrical surface of the compression piston 67 to keep the compression space 66 airtight.

The expansion section 90 has an expansion cylinder 97 formed by making a hole in the cylinder housing 74, an expansion piston 93 which is hollow inside and reciprocates in the expansion cylinder 97, and one end of which can swing on the cross guide head 44. The expansion space 92 is mounted and has the other end fixed to the expansion piston 93, and has an expansion space 92 formed by the piston rod 69 connecting these parts and the head side of the expansion piston 93 and the expansion cylinder 97. A cold head portion 21 is provided on the outer peripheral portion of 92.
9 is formed.

The internal space of the expansion cylinder is formed so as to form a part of the gas flow path, and the compression space and the expansion space are communicated with each other.

The expansion piston 93 is formed by an upper expansion piston 93a and a lower expansion piston 93b,
The expansion piston ring 104 is attached to the lower expansion piston 93b to maintain the airtightness of the expansion space 92.

2 and 3 show the upper expansion piston 93a.
5A and 5B are a top view and a side sectional view of the lower expansion piston 93b, and FIG. 4 is a side sectional view of when these are assembled.

Piston coupling screw grooves 110 are formed on the outer cylindrical surface of the lower end portion of the upper expansion piston 93a and the inner cylindrical surface of the upper end portion of the lower expansion piston 93b, and they are integrated by screwing them together. The expanded piston 93 is formed.

The upper expansion piston 93a is a cylindrical member having upper and lower openings, and the inner cylindrical surface near both openings has
A removable heat storage material support ring 112 that supports the heat storage material 176 inside the upper expansion piston 93a is mounted.

Since the head portion of the upper expansion piston 93a (on the side of the expansion space 92) is also opened, the resistance when the working gas moves between the expansion space 92 and the inside of the upper expansion piston 93a is minimized, Therefore, the compressed or expanded working gas can be effectively used for generating cold heat, and the refrigeration efficiency can be improved.

When the upper expansion piston 93a and the lower expansion piston 93b are screwed together, the lower end of the upper expansion piston 93a comes into contact with the bottom surface of the lower expansion piston 93b, or substantially comes into contact therewith, The heat storage material 176 can be effectively stored in the internal space of the expansion piston 93.

The heat storage material 176 accommodated in the expansion piston 93 is formed by laminating a large number of mesh-shaped metal sheets made of brass or stainless steel.

Then, when the working gas expanded in the expansion space 92 and lowered in temperature flows toward the compression space 66, the cold heat of the working gas is stored and the cold heat is expanded from the compression space 66. It is used to cool the working gas flowing to 92.

When the working gas that has been compressed in the compression space 66 and has increased in temperature flows from the compression space 66 toward the expansion space 92, the heat of the working gas is stored and the heat is expanded. Used to heat the working gas flowing from the compressed space 66 to the compressed space 66.

With this structure, the upper expansion piston 93a in which the heat storage material 176 is housed is replaced by the lower expansion piston 9a.
Even if it is combined with 3b, a large space is not opened unlike the conventional case, so that the refrigeration efficiency can be improved.

Further, since the heat storage material 176 is a laminated body formed by laminating mesh-like metal sheets, if it is simply stored in the expansion cylinder as in the conventional case,
With the reciprocating motion of the expansion cylinder, the metal sheet jumps up, and there is a disadvantage that abrasion powder is generated due to friction between the sheets, frictional heat is generated, or damage is caused, but in the present invention, the heat storage material support ring 112 causes Since it is supported, such inconvenience can be prevented and reliability is improved.

The heat radiating portion 193 is provided mainly for the purpose of promptly releasing the heat of the working gas, which has been compressed by the compressing portion 64 and has risen in temperature, to the outside. The heat radiating portion 193 is provided in the cylinder housing near the compression chamber. It has the radiation fin 195 provided in close contact.

In the Stirling refrigerator 1, the crank 38
When the engine rotates, the oil 248 stored at the bottom of the crank space 36 is scraped up and adhered to the sliding portion between the crank 38 and the connecting rod 41, etc., to lubricate these sliding portions. .

At this time, the reciprocating motion of the cross guide head 44 causes the oil 248 to be sent to the compression piston 67 or the expansion piston 93 side, and this is moved to the compression space 66 or the expansion space 92 by the reciprocating motion of the compression piston 67 or the expansion piston 93. It is sent in and causes a reduction in refrigeration efficiency.

Therefore, in the present invention, in order to prevent the oil 248 from adhering to the compression piston 67 and the expansion piston 93, the oil seal portion 148 having an oil seal bellows as a main component is provided.

The oil seal portion 148 is the fixed plate 2
43, the expansion piston 93, and the compression piston 67, an oil seal bellows 149, a washer-shaped upper mounting ring 150 having an upper end of the oil seal bellows 149 welded, and a lower end of the oil seal bellows 149 welded. It has a washer-shaped lower mounting ring 151.

As the oil seal bellows 149, a metal forming bellows integrally formed by pressing a metal material or a metal welding bellows assembled by welding is used.

The upper mounting ring 150 is the piston rod 69.
It is sandwiched between the piston side flange 103 and the compression piston or expansion piston, and is tightly fixed by tightening the piston mounting screw 102.

When the lower mounting ring 151 is fixed to the crank housing via the fixing plate, the lower mounting ring 151 is closely fixed to the crank housing.

As a result, it is possible to completely prevent the inconvenience that the oil 248 adheres to the compression piston or the expansion piston and enters the compression space 66 or the expansion space 92.

Since the oil seal bellows is provided in close contact with the piston rod 69, the crank housing, etc. in an airtight manner, the space between the compression piston or expansion piston and the oil seal bellows (this space is called a back pressure chamber). ) Is airtight.

The back pressure chamber 154 is formed on each of the back pressure side of the compression piston 67 and the back pressure side of the expansion piston 93. If they are independent of each other, the reciprocating motion of the compression piston and the expansion piston causes Since the pressure in the back pressure chamber also fluctuates, the motor load increases correspondingly and the refrigeration efficiency is reduced.

Therefore, in the present invention, the back pressure chamber communicating hole 155 is provided so that the back pressure chamber on the compression piston 67 side and the back pressure chamber on the expansion piston 93 side communicate with each other so that the pressure is mutually relieved.

Next, the operation of the Stirling refrigerator 1 having such a configuration will be described. When the motor 14 is driven, its rotational power is transmitted to the crankshaft 37 via the motor shaft 17.

A crank 38 is eccentrically attached to the crank shaft 37, and a cross guide head 44 is connected to the crank 38 via a connecting rod 41. Therefore, the rotational power is the reciprocating power of the cross guide head 44. To be converted.

When the cross guide head 44 reciprocates, the expansion piston 9 connected through the piston rod.
3 and the compression piston 67 reciprocate to compress the working gas,
Expands.

At this time, oil 248 is generated by the crank 38.
Is attached to the cross guide head 44 and the like, but the crank space 36 and the back pressure chamber 15 are prevented by the oil seal bellows 149.
Since the oil 248 is completely separated from No. 4, the oil 248 cannot enter the back pressure chamber 154 and does not enter the compression space 66 or the expansion space 92.

In this way, when the expansion piston 93 and the compression piston 67 reciprocate and the expansion piston 93 approaches the top dead center and slows down, the compression piston 67 moves rapidly near the middle toward the top dead center. As a result, the working gas is substantially adiabatically compressed and its temperature rises.

The compressed working gas flows through the gas passage 175, radiates heat in the heat radiating portion 193, flows into the inside of the lower hole 113 of the expansion piston 93, and the expansion piston 93 concerned.
It passes through the heat storage material 176 housed inside and flows into the expansion space 92 from the opening on the head side.

Then, the compression piston 67 approaches the top dead center, and its speed also slows down.

Then, the expansion piston 93 suddenly moves toward the bottom dead center, whereby the expansion space 92 rapidly expands, and the working gas in the expansion space 92 adiabatically expands and cools.

As a result, the temperature of the cold head portion 219 is lowered, and the cold heat is used for the cold heat utilization equipment. For example, by forming a circulation circuit capable of exchanging heat with the cold head portion 219, cold heat can be transferred to the load.

When the expansion piston 93 moves from the bottom dead center to the top dead center, the compression piston 67 moves from the intermediate position toward the bottom dead center, whereby the working gas is expanded.
2 flows into the inside of the expansion piston 93 from the head opening of the expansion piston 93, stores heat in the heat storage material 176, and flows from the lower hole 113 to the compression space 66 via the gas flow path 175.

At this time, the working gas that has expanded and decreased in temperature stores cold heat in the heat storage material 176, flows into the compression space 66 through the heat radiation portion 193, and one cycle is completed.

[0072]

As described above, according to the first aspect of the invention, the expansion piston is formed of the upper expansion piston having the heat storage material therein and the lower expansion piston engaging with the upper expansion piston. Since the lower end of the upper expansion piston is inserted inside the lower expansion piston so that the lower end of the upper expansion piston and the bottom surface of the lower expansion piston abut or substantially abut. , The internal space of the expansion piston can be effectively used, and the refrigeration efficiency is improved.

According to the second aspect of the present invention, the upper expansion piston is formed by the tubular member, and both ends thereof are opened. Therefore, the amount of working gas flowing in and out of the expansion piston increases, and the operation is performed by being compressed and expanded. The gas can be effectively used for generating cold heat, and the refrigeration efficiency is improved.

According to the third aspect of the invention, the heat storage material support ring for supporting the heat storage material inside the upper expansion piston is mounted on the inner cylindrical surface near both openings of the upper expansion piston, and two rings are provided. Since the heat storage material is sandwiched and supported by the heat storage material support ring, it is possible to prevent the heat storage material from vibrating or being damaged, thereby improving reliability.

[Brief description of drawings]

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

FIG. 2 is a configuration diagram of an upper expansion piston, in which (a) is a top view and (b) is a side sectional view.

3A and 3B are configuration diagrams of a lower expansion piston, in which FIG. 3A is a top view and FIG. 3B is a side sectional view.

FIG. 4 is a side sectional view of an expansion piston.

5A and 5B are configuration diagrams of an upper expansion piston applied to the description of the conventional technique, FIG. 5A is a top view and FIG. 5B is a side sectional view.

6A and 6B are configuration diagrams of a lower expansion piston applied to the description of the related art, in which FIG. 6A is a top view and FIG. 6B is a side sectional view.

FIG. 7 is a side sectional view of an expansion piston applied to the description of the conventional technique.

[Explanation of symbols]

1 Stirling refrigerator 33 Cold heat generator 66 compression space 67 Compression piston 68 compression cylinders 92 Expansion space 93 Expansion piston 93a Upper expansion piston 93b Lower expansion piston 97 expansion cylinder 110 Piston coupling screw groove 112 Heat storage material support ring 113 Lower hole 175 gas flow path 176 heat storage material

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[Procedure amendment]

[Submission date] July 9, 2002 (2002.7.9)

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0036

[Correction method] Change

[Correction content]

The expansion section 90 has an expansion cylinder 97 formed by making a hole in the cylinder housing 74, an expansion piston 93 which is hollow inside and reciprocates in the expansion cylinder 97, and one end of which can swing on the cross guide head 44. The expansion space 92 is mounted and has the other end fixed to the expansion piston 93, and has an expansion space 92 formed by the piston rod 69 connecting the expansion piston 93, the head side of the expansion piston 93 and the expansion cylinder 97. Cold head part 21 on the outer circumference
9 is formed.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0066

[Correction method] Change

[Correction content]

The compressed working gas flows through the gas flow path 175, radiates heat in the heat radiating portion 193, flows into the inside of the lower hole 102 of the expansion piston 93, and the expansion piston 93 concerned.
It passes through the heat storage material 176 housed inside and flows into the expansion space 92 from the opening on the head side.

[Procedure 3]

[Document name to be amended] Statement

[Name of item to be corrected] 0070

[Correction method] Change

[Correction content]

When the expansion piston 93 moves from the bottom dead center to the top dead center, the compression piston 67 moves from the intermediate position toward the bottom dead center, whereby the working gas is expanded.
2 flows into the expansion piston 93 from the head opening of the expansion piston 93, stores heat in the heat storage material 176, and flows from the lower hole 102 into the compression space 66 via the gas flow path 175.

[Procedure amendment 4]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 1

[Correction method] Change

[Correction content]

[Figure 1]

Claims (3)

[Claims] 1. A compression piston for compressing the working gas in the compression space, an expansion piston for expanding the working gas in the expansion space, and a gas flow path for allowing the working gas to move back and forth between the expansion space and the compression space. A Stirling refrigerator comprising a heat storage material that stores heat of working gas that travels between the expansion space and the compression space via the gas flow path, wherein the expansion piston is an upper expansion piston in which the heat storage material is installed. And a lower expansion piston that engages with the upper expansion piston, and a lower end portion of the upper expansion piston is inserted inside the lower expansion piston, and a lower end portion of the upper expansion piston and the lower expansion piston are inserted. A Stirling refrigerator, wherein the piston is engaged with the bottom surface of the piston in a state of abutting or substantially abutting. 2. The Stirling refrigerator according to claim 1, wherein the upper expansion piston is formed of a tubular member, and both ends thereof are opened. 3. A heat storage material support ring for supporting the heat storage material inside the upper expansion piston is mounted on an inner cylindrical surface near both openings of the upper expansion piston,
The Stirling refrigerator according to claim 1 or 2, wherein two heat storage material support rings sandwich and support the heat storage material.