JP2003287310A - Stirling refrigerating machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent degradation of the lubrication function attributable to the compatibility of the working gas with the lubricating oil in a crank chamber of a stirling refrigerating machine, and to prevent mechanical losses (power losses) in a sliding part from being increased, or the service life caused by wear from being shortened. <P>SOLUTION: Degradation of the viscosity of the lubricating oil by solution of the working gas in the lubricating oil is prevented by using the lubricating oil such as mineral oil free from any compatibility with the working gas (Example: He) filled in the crank chamber 5, and increase of the mechanical losses (power losses) and shortening of the service life by the wear at sliding parts between crank parts 12 and 13 and connecting rods, and between connecting rods 8 and 9 and cross guide heads 10 and 11 are prevented. <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, and more particularly to a combination of lubrication and a refrigerant for a Stirling refrigerator.

[0002]

2. Description of the Related Art In recent years, as a refrigerating device as an alternative to CFCs for global environmental problems, and having a wider operating temperature than conventional cooling devices, therefore, cold or heat utilization equipment for business use such as freezer, refrigerator, throw-in cooler, etc. , Low temperature liquid circulator, low temperature incubator, constant temperature bath, heat shock test device, freeze dryer, temperature characteristic test device, blood / cell storage device, cold cooler, and various other cooling and heating devices The Stirling refrigerator is in the spotlight as a refrigerator that can be applied to cold heat utilization equipment, is compact, has a high coefficient of performance, and has good energy efficiency.

In a Stirling refrigerator, a working gas is hermetically sealed in a housing which constitutes a main body and has a crank chamber and a motor chamber. On the other hand, the working gas flows between the compression chamber (high temperature chamber) and the expansion chamber (low temperature chamber),
A heat exchanger for cooling (low temperature side heat exchanger) and a heat exchanger for radiating heat (high temperature side heat exchanger) arranged along this flow path perform heat exchange with the cold heat refrigerant and the heat radiating refrigerant, respectively. Be seen.

[0004]

By the way, the crank chamber is filled with a working gas having a small molecular weight (eg, He), and moreover, in the crank chamber, the crank portion and the connecting rod, and the connecting rod and the cross guide head are filled. It has a unique structure in which lubricating oil is supplied to lubricate mechanical sliding parts such as sliding parts with connecting pins.

The present inventors have found that there is a particular problem related to lubrication due to the unique structure of such Stirling refrigerators. That is, the lubricating oil that lubricates the sliding portion in the crank chamber comes into contact with the working gas filled in the crank chamber, and the working gas melts into the lubricating oil. As a result, the viscosity of the lubricating oil is lowered, the function as the lubricating oil is lowered, the mechanical loss (power loss) in the sliding portion is increased, and the life due to wear is shortened.

An object of the present invention is to solve the problem of the deterioration of the lubricating function due to the compatibility between the working gas and the lubricating oil, and to prevent the deterioration of the lubricating function of the lubricating oil due to the penetration of the working gas. It is an object of the present invention to realize means for solving the problem that the mechanical loss (power loss) in the sliding portion is increased and the life is shortened due to wear.

[0007]

In order to solve the above-mentioned problems, the present invention uses a lubricating oil that is incompatible with the working gas of a Stirling refrigerator, so that the working gas does not dissolve in the lubricating oil. A Stirling refrigerator having a moving part lubricated.

The working gas is helium, and the lubricating oil is a mineral oil which is not compatible with the helium, an ether oil,
It may be ester oil or alkylbenzene oil.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below based on examples with reference to the drawings. 1 to 3 are diagrams illustrating a Stirling refrigerator to which the present invention is applied, and FIG. 1 is a front view illustrating the entire configuration of the Stirling refrigerator 1. FIG. 2 is a diagram for explaining a main part of the Stirling refrigerator 1, and FIG. 3 is a diagram partially showing a right side view of a cross section.

The housing 2 formed of the casting of the Stirling refrigerator 1 is filled with He and is maintained in a semi-hermetic state, and the motor chamber 4 and the crank chamber 5 which communicate with each other through the partition wall 3. Have and. A motor 6 capable of rotating in the forward and reverse directions is disposed in the motor chamber 4, and in the crank chamber 5, a crankshaft 7, connecting rods 8 and 9 which are rotationally driven by the motor 6, and cross guide heads 10 and 1 are provided.
A drive mechanism such as 1 is provided.

Two crank parts 1 of the crankshaft 7
Reference numerals 2 and 13 are formed with a phase difference so that the crank portion 13 moves ahead of the crank portion 12 when the motor 6 rotates in the normal direction. As this phase difference, a phase difference of about 90 degrees is generally adopted. Connecting rods 8 and 9 are attached to the crank portions 12 and 13, and cross guide heads 10 and 11 are attached to the connecting rods 8 and 9.

A cylinder block 15 is attached to the upper portion of the crank chamber 5 of the housing 2 with a bolt 16 via a seat portion 14. The cylinder block 15 forms a compression cylinder 17 and a part (lower part) of the expansion cylinder 18.

The space above the compression piston 19 (compression space) that reciprocates in the compression cylinder 17 is the high temperature chamber 20,
In this, the working gas He is compressed and becomes high temperature.
The compression piston rod 21 connects the compression piston 19 and the cross guide head 10, and is provided so as to extend from the crank chamber 5 to the compression cylinder 17. The oil seal bellows 22 is used for the compression piston rod 21 and the housing 2.
Is installed between the upper parts of the cylinders, and seals between the compression cylinder 17 and the crank chamber 5 to prevent oil from rising from the crank chamber 5.

On the other hand, the expansion cylinder 18 has a lower portion constituted by the cylinder block 15 as described above, and an upper portion thereof is
It is composed of an inner cylinder 23 of a heat radiating heat exchanger 29 described later and an inner cylinder 24 of a cooling heat exchanger. An upper space (expansion space) of the piston 25 that slides back and forth in the expansion cylinder 18 is a low temperature chamber 26, in which the working gas expands and becomes a low temperature.

The expansion piston rod 27 connects the expansion piston 25 and the cross guide head 11 and extends from the crank chamber 5 into the expansion cylinder 18. An oil seal bellows 28 is attached between the expansion piston rod 27 and the upper portion of the housing 2 to seal between the expansion cylinder 18 and the crank chamber 5 and prevent oil from rising from the crank chamber 5. The expansion piston 25 is the compression piston 19
It moves ahead by 90 degrees in phase.

A heat-radiating heat exchanger (high-temperature-side heat exchanger) 29, a regenerator 30, and a cooling heat-exchanger (low-temperature-side heat exchanger) 31 communicate with each other and are annularly arranged so as to surround the expansion cylinder 18. It is set up. A manifold (flow path for working gas) 32 is formed around the lower end of the heat radiating heat exchanger 29 and around the expansion cylinder 18.

At the upper end of the compression cylinder 17,
Communication hole 33 for communicating the high greenhouse 20 and the manifold 32
Are formed. The high greenhouse 20 and the low temperature chamber 26 are configured to sequentially communicate with each other through the communication hole 33, the manifold 32, the heat radiating heat exchanger 29, the regenerator 30, and the cooling heat exchanger 31.

The cylinder block 15 has a heat radiating heat exchange housing 34 on its upper part. A heat exchanger tube 37 is fitted between the heat radiating heat exchange housing 34 and the inner cylinder 23, and the heat radiating heat exchanger (high temperature side heat exchanger) 2
9 is composed. The heat exchanger tube 37 has, on its inner surface,
It has a narrow groove 35 that forms a flow path of the working gas, and has a radiation fin 36 on the outer surface.

The working gas passes through the narrow groove 35 and the cooling water flows through the heat dissipation passage 38 between the heat dissipation housing 34 for heat dissipation and the heat dissipation fins 36, whereby the heat of the working gas is dissipated to the cooling water. A lid plate 39 is watertightly fixed to both left and right side surfaces of the cylinder block 15, and a cooling water passage 40 is formed between the lid plate 39 and the cylinder block 15. The cooling water passage 40 communicates with the inlet 41 and the heat dissipation passage 38.
And is formed so as to surround the compression cylinder 17 and the expansion cylinder 18.

A cooling water inflow port 42 is provided in the heat radiation path 38, an outflow port 43 is provided in the cooling water path 40, and the inflow port 40 and the outflow port 43 are not shown in the drawing, but are not shown in the drawing. It is connected to an air-cooled radiator (radiator) having a cooling fan via a water circulation pump.

The lower part of the inner cylinder 24 is fitted with the inner cylinder 23 and constitutes a part of the expansion cylinder 18. A cooling heat exchange housing 44 is arranged on the outer peripheral side of the upper part of the inner cylinder 24. It is detachably fixed to the cylinder block 15. The heat exchange housing 44 for cooling has a plurality of narrow grooves 45 on its inner surface, is fitted with the inner cylinder 24 to form a working gas passage 46, and has cooling fins 47 on its outer surface.
This constitutes the cooling heat exchanger (low temperature side heat exchanger) 31.

The heat exchanger 31 for cooling cools the cold heat refrigerant of the cold heat utilizing equipment using the cold heat of the Stirling refrigerator of the present invention. Air, water, alcohol, HFE, PFC or the like is used as the cold heat refrigerant.

A regenerator 30 made of a cold storage material such as a metal mesh is arranged in an annular space between the inner cylinder 24 and the cooling heat exchange housing 44.

The space between the oil seal bellows 28 and the expansion piston 25 (the same applies to the space between the oil seal bellows 22 and the compression piston 19) is called a buffer space (buffer chamber) 48. The buffer space 48 is connected to the buffer tank 51 by a pipe 49,
The buffer tank 51 is connected to the crank chamber 5 (or the motor chamber 4) of the housing 2 by a pipe 50.

The present invention is characterized by the following structure in the Stirling refrigerator having the above structure. In FIG. 1, the housing 2 including the crank chamber 5 is filled with He, which is a working gas, and the housing 2 is hermetically sealed via the buffer tank 51 at substantially the same pressure as the buffer space 48.

Lubricating oil is sent to the sliding portion between the crank portions 12 and 13 and the connecting rods 8 and 9 through the hollow lubrication supply passage 52 and the lubricating oil holes 53 and 54 provided in the crankshaft 7 for lubrication. It is carried out. Further, the lubricating oil is sent to the sliding portions between the connecting rods 8 and 9 and the connecting pins 10 ′ and 11 ′ of the cross guide heads 10 and 11 through the lubricating supply passages 55 and 56 provided in the connecting rods 8 and 9 for lubrication. To do.

As described above, the lubricating oil sent to the mechanical sliding portion in the crank chamber 5 for lubrication is in contact with the He filled in the crank chamber 5, and the lubricating oil is used as a working gas. The phenomenon that is melted occurs. As a result, the viscosity of the lubricating oil decreases and the lubricating function decreases. As a result, there arises a problem that the mechanical loss (power loss) in the lubrication part increases and the life is shortened due to wear.

In particular, when the operation is started after the operation is stopped and the temperature of the entire apparatus is low, the friction of the sliding portion is increased, the mechanical loss (power loss) is increased, and the life due to wear is shortened.

Therefore, in the present invention, as the lubricating oil, the incompatible lubricating oil into which the working gas is not dissolved is used. In a Stirling engine, He or the like is usually used as a working gas as a working gas having a small molecular weight.
In the case of e, mineral oil that is not compatible with He (eg, 3 GSD
Molybdenum mineral oil, etc.), ether oil, ester oil, alkylbenzene oil, etc. are used.

As the working gas, it is possible to use hydrogen gas, nitrogen gas, etc. in addition to He. In that case, hydrogen gas, nitrogen gas, etc. are not dissolved, that is, incompatible lubricating oil is used. .

In the present invention, by using such an incompatible lubricating oil, it is possible to prevent the working gas from dissolving in the lubricating oil and to reduce the viscosity of the lubricating oil. It is possible to prevent the friction of the moving part from increasing.

(Operation) Next, the operation of the Stirling refrigerator of the above embodiment of the present invention will be described. The motor 6 rotates the crankshaft 7 in the forward direction, and the crank portions 12 and 13 in the crank chamber 5 rotate 90 degrees out of phase.
The connecting rod 8 connected to the crank portions 12 and 13,
The compression piston 19 and the expansion piston 25 reciprocate through the cross guide heads 10 and 11, the compression piston rod 21, and the expansion piston rod 27 with a phase difference of 90 degrees.

While the expansion piston 25 is moving 90 degrees ahead and moving slowly near the top dead center, the compression piston 19 moves rapidly near the middle toward the top dead center to compress the working gas. The compressed working gas flows into the narrow groove 35 of the heat radiating heat exchanger 29 through the communication hole 33 and the manifold 32, and radiates heat to the cooling water flowing through the heat radiating passage 38. Further, the working gas is cooled by the cold heat stored in the regenerator 30, passes through the narrow groove 45, and flows into the low temperature chamber 26 (expansion space).

When the compression piston 19 slowly moves near the top dead center, the expansion piston 25 rapidly moves toward the bottom dead center, and the working gas flowing into the low temperature chamber 26 (expansion space) rapidly expands. Then cold heat is generated. As a result, the head portion (called a cold head) 48 including the heat exchanger 31 for cooling is cooled to a low temperature.

Then, in the cooling heat exchanger 31, the cold heat refrigerant for the equipment utilizing cold heat, which is in contact with the cooling fins 47, is cooled. When the expansion piston 25 moves from the bottom dead center to the top dead center, the compression piston 19 moves from the intermediate position to the bottom dead center, and the working gas flows from the low temperature chamber 26 through the narrow groove 45 of the cooling heat exchanger to the regenerator. Cold heat flowing into the working gas 30 and contained in the working gas is stored in the regenerator 30. The cold heat stored in the regenerator 30 is transferred from the high temperature chamber 20 to the heat radiating heat exchanger 29 as described above.
The working gas sent through is reused for cooling again.

Then, the cold heat refrigerant cooled in the cooling heat exchanger is sent from the outflow pipe 64 to various cold heat utilization devices and used for cooling. For example, the cold heat refrigerant is sent to a cold heat refrigerant pipe in a cold heat utilization apparatus such as a freezer, and performs a freezing or cooling action in the cold heat utilization apparatus. Then, the cold heat utilization equipment circulates back to the cooling heat exchanger 31 through the inflow pipe 65 and is cooled again.

The cooling water sent from the radiator (radiator) flows into the heat radiating heat exchanger 38 through the inlet 42, passes through the heat radiating passage 38, and cools the working gas. Further, this cooling water flows into the cooling water passage 40 and flows around the compression cylinder 17 and the expansion cylinder 18. As a result, the compression cylinder 17 and the expansion cylinder 18 formed inside the cylinder block 15 are cooled from the surroundings. After that, the cooling water flows out from the outflow port 43, is cooled by the cooling fan in the radiator, and is circulated again to the heat radiation heat exchanger 29.

The buffer tank 51 has a buffer space 48.
The housing 2 has a uniform pressure, absorbs pressure fluctuations in the buffer space 48, and absorbs pressure fluctuations in the housing 2 so as not to affect the buffer space.

When the operation of the Stirling refrigerator is started, the lubricating oil is supplied from the lubricating oil supply passage 52 of the crankshaft 7 to the crank portions 12 and 13 and the connecting rod 8.
9 is sent to the sliding portion with the connecting rod 9, and the lubricating oil is further supplied from the lubricating oil supply passages 55, 56 of the connecting rods 8, 9 to the connecting rod 8,
9 and the connecting pin 10 'of the cross guide heads 10 and 11,
It is sent to the sliding part 11 'and lubricated.

By the way, in the present invention, since the incompatible lubricating oil in which the working gas does not dissolve is used as the lubricating oil, the working gas does not dissolve in the lubricating oil. This does not reduce the viscosity of the lubricating oil.

Therefore, even when the temperature in the crank chamber is low at the time of operating the Stirling refrigerator, particularly when starting up the refrigerator, it is possible to prevent an increase in mechanical loss due to friction in the mechanical sliding portion. In addition, it is possible to prevent the life from being shortened due to abrasion.

The embodiment of the Stirling refrigerator according to the present invention has been described above based on the embodiments, but the present invention is
Needless to say, the present invention is not limited to the above-described embodiments, and various embodiments are possible within the scope of the technical matters described in the claims.

[0043]

Since the present invention is constructed as described above,
It is possible to prevent the deterioration of the lubricating function due to the compatibility of the working gas and the lubricating oil in the crank chamber of the Stirling refrigerator, and as a result, to prevent the deterioration of the lubricating function of the lubricating oil due to the penetration of the working gas and to prevent sliding It is possible to prevent an increase in mechanical loss (power loss) in the part and a reduction in life due to wear.

[Brief description of drawings]

FIG. 1 is a front view for explaining the overall configuration of a Stirling refrigerator according to the present invention.

FIG. 2 is a diagram showing a main part of the Stirling refrigerator of FIG.

FIG. 3 is a right side partially cutaway front view illustrating a Stirling refrigerator according to the present invention.

FIG. 4 is a diagram showing a main part of a crank chamber of a Stirling refrigerator according to the present invention.

[Explanation of symbols]

1 Stirling Refrigerator 2 Housing 3 Partition Wall 4 Motor Chamber 5 Crank Chamber 6 Motor 7 Crank Shafts 8, 9 Connecting Rods 10, 11 Cross Guide Heads 10 ', 11' Connecting Pins 12, 13 Cranks 14 Seats 15 Cylinder Blocks 16 Bolts 17 compression cylinder 18 expansion cylinder 19 compression piston 20 upper space (compression space) high temperature chamber 21 compression piston rod 22 oil seal bellows 23 inner cylinder 24 inner cylinder 25 of cooling heat exchanger expansion piston 26 upper space (expansion space) is low temperature Chamber 27 Expansion piston rod 28 Oil seal bellows 29 Heat dissipation heat exchanger (high temperature side heat exchanger) 30 Regenerator 31 Cooling heat exchanger (low temperature side heat exchanger) 32 Manifold (working gas flow path) 33 Communication Hole 34 Heat dissipation housing 35 for heat dissipation Inner surface of heat exchanger tube Fine groove for working gas flow path 36 Radiating fins 37 Heat exchanger tube 38 Radiating heat exchange housing Radiating path between radiation fins 39 Lid plate 40 Cooling water passage 41 Inlet 42 Cooling water inlet 43 to cooling passage 43 Cooling water passage Outlet 44 of cooling heat exchange housing 45 a plurality of fine grooves on the inner surface of the cooling heat exchange housing 46 working gas flow passage 47 cooling fins 48 buffer space (buffer chamber) 49 pipe 51 buffer tank 52 lubrication supply passages 53, 54 lubrication Oil holes 55, 56 Lubrication supply passage

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Goo Nakazaki             2-5-3 Keihan Hondori, Moriguchi City, Osaka Prefecture             Within Yo Denki Co., Ltd. (72) Inventor Takashi Inoue             2-5-3 Keihan Hondori, Moriguchi City, Osaka Prefecture             Within Yo Denki Co., Ltd. (72) Inventor Ryosuke Asahibichi             2-5-3 Keihan Hondori, Moriguchi City, Osaka Prefecture             Within Yo Denki Co., Ltd. (72) Inventor Dai Kanai             2-5-3 Keihan Hondori, Moriguchi City, Osaka Prefecture             Within Yo Denki Co., Ltd. (72) Inventor Takehiro Nishikawa             2-5-3 Keihan Hondori, Moriguchi City, Osaka Prefecture             Within Yo Denki Co., Ltd. (72) Inventor Hiroshi Nishikawa             2-5-3 Keihan Hondori, Moriguchi City, Osaka Prefecture             Within Yo Denki Co., Ltd. (72) Inventor Shinya Itabashi             2-5-3 Keihan Hondori, Moriguchi City, Osaka Prefecture             Within Yo Denki Co., Ltd. (72) Inventor Hideyuki Inoue             2-5-3 Keihan Hondori, Moriguchi City, Osaka Prefecture             Within Yo Denki Co., Ltd. (72) Inventor Hirosuke Ogasawara             2-5-3 Keihan Hondori, Moriguchi City, Osaka Prefecture             Within Yo Denki Co., Ltd. (72) Inventor Tetsuya Kato             2-5-3 Keihan Hondori, Moriguchi City, Osaka Prefecture             Within Yo Denki Co., Ltd. (72) Inventor Takashi Atomic             2-5-3 Keihan Hondori, Moriguchi City, Osaka Prefecture             Within Yo Denki Co., Ltd. F-term (reference) 3H003 AA02 AC03 BD00 CD04

Claims (2)

[Claims] 1. A Stirling refrigerator, wherein a lubricating oil that is incompatible with the working gas of the Stirling refrigerator is used, and the sliding portion is lubricated in a state where the working gas does not dissolve in the lubricating oil. 2. The Stirling refrigerator according to claim 1, wherein the working gas is helium, and the lubricating oil is mineral oil, ether oil, ester oil or alkylbenzene oil which is incompatible with the helium. .