JP3373894B2 - Refrigeration equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerating apparatus for realizing an ultra-low temperature by using a cold storage type refrigerator such as a Stirling refrigerator.

[0002]

2. Description of the Related Art In the field of advanced technology such as the field of biotechnology and the field of electronic devices, there is an urgent need to develop an ultralow temperature preservation technique for various samples and various materials. In particular, regenerators such as Stirling refrigerators have been attracting attention as means for achieving the above-mentioned ultra-low temperature, and are being widely used for various infrared sensors, freezers for cooling superconducting devices and the like, biomedical freezers, freezers and the like.

The operation principle of the two-piston Stirling refrigerator will be described with reference to FIG.

The Stirling refrigerator 1 has a gas flow path 5 in which a gas compressor 2 and an expander 3 are interposed, and a regenerator 4 is interposed therebetween.
The radiator 6 and the radiator 7 are arranged on the gas compressor 2 side of the gas flow path 5 on the gas compressor 2 side and the inlet side of the regenerator 4 on the other hand, and the freezing take-out portion 8 is formed on the upper part of the expander 3. Further, a crank mechanism portion 9 is arranged behind the gas compressor 2 and below the expander 3.

The gas compressor 2 is for compressing a refrigerant gas having a cryogenic boiling point such as helium according to a predetermined cycle and supplying the compressed refrigerant gas to the expander 3. In the gas compressor 2, a compression cylinder is used. A compression space 11 for compressing a refrigerant gas is formed inside the main body 10, a compression piston 13 is slidably fitted in a compression cylinder 12, and the compression piston 13 reciprocates by the action of a crank mechanism section 9 described later. It is like this.

The expander 3 expands the compressed refrigerant gas supplied from the gas compressor 2 via the regenerator 4. The expander 3 has an expansion cylinder 15 inside the expander body 14 in the vertical direction. The expansion piston 16 is slidably fitted in the expansion cylinder 15 in the vertical direction, and the freezing generation section 17 is formed inside the expansion machine 3 as an expansion space in which a low temperature is generated.

The regenerator 4 is formed in a cylindrical shape between the inner circumference of the expander body 14 and the outer circumference of the expansion cylinder 15, and is a compressed refrigerant gas supplied to the expander 3 through the gas flow path 5. On the other hand, when the refrigerant gas expanded and cooled in the freezing generation section 17 is returned to the gas compressor 2 while cooling the refrigerant, the refrigerant is cooled and stores cold. Stainless steel, lead, and the like are used, and they are formed into a cylindrical shape having a large number of fine holes through which a refrigerant gas passes.

The gas flow path 5 is a pipe connecting the gas compressor 2 and the expander 3 so that the compressed refrigerant gas evenly passes through the regenerator 4 at the inlet side of the regenerator 4. The radiator 6 and the radiator 7 lower the compressed high-temperature refrigerant gas to near room temperature, and the radiator 6 has a large number of disk-shaped fins provided upright on the outside of the body of the compression cylinder body 10 for heat radiation. Bowl 7
Has a large number of circular fins standing on the outside of the body of the expander body 14. The freezing take-out unit 8 includes the freezing generation unit 17
The cold heat generated in 1 is taken out to a low temperature tank (not shown) or the like, and is covered with a plate-like body such as stainless steel on the upper portion of the expander body 14.

The crank mechanism section 9 reciprocates by the action of a crank motion using a drive motor (not shown) as a drive source for the compression piston 13 and the expansion piston 16. A crank chamber 22 having a guide portion 20 formed at the rear and a guide portion 21 below the expansion cylinder 15 is provided. Lubricating oil 23 is stored at the bottom of the crank chamber 22. A crank mechanism 24 is arranged inside. A connecting rod 25 extending from the crank mechanism 24 has a cross guide 26 slidably fitted in a guide receiver 20a of the guide portion 20, and a piston rod 27 communicating with the cross guide 26 is provided in the guide portion 20. The connecting rod 28 extending from the crank mechanism 24 is slidably fitted to the guide receiver 21a of the guide portion 21 while being connected to the rear portion of the compression piston 13 through the through hole 20b. Cross guide 29
Is connected to the rear of the expansion piston 16.

Reference numeral 31 is a piston seal that disconnects the compression space 11 and the space 32 behind the compression piston 13 from 3
Reference numeral 3 denotes an oil seal that prevents the lubricating oil 23 in the crank chamber 22 from entering the space 32. Further, 34 is a piston seal that disconnects the space 35 behind the freezing generator 17 and the expansion piston 16, and 36 is an oil seal that prevents the lubricating oil 23 in the crank chamber 22 from entering the space 35.

First, when the crank mechanism 24 of the crank mechanism portion 9 is driven by the rotation of a drive motor (not shown), the compression piston 13 in the compression cylinder 12 of the gas compressor 2 moves to the compression space 11 side and the compression space 11 Refrigerant gas, such as helium or nitrogen, which is difficult to liquefy, is compressed. The compressed refrigerant gas is radiated to the outside by the radiator 6 provided on the outer periphery of the compression cylinder body 10 and cooled to near room temperature, passes through the gas flow path 5, and is further radiated by the radiator 7.
It is cooled by and flows into the regenerator 4.

The refrigerant gas flowing into the regenerator 4 is cooled by a material having a large specific heat, for example, a regenerator material made of copper or lead wire mesh or spheres, and the cooled refrigerant gas is frozen by the freezing generation section 17 of the expander 3. And the freezing generation unit 17 is in a high pressure state.

Thereafter, the expansion piston 16 in the expansion cylinder 15 of the expander 3 descends with a phase difference of about 90 ° with the compression piston 13. Thereby, the freezing generation part 17 as an expansion space is expanded, and the high-pressure refrigerant gas flowing from the regenerator 4 into the freezing generation part 17 is suddenly expanded,
Since the pressure of the refrigerant gas in the freezing generation unit 17 suddenly drops, the refrigerant gas has a low temperature.

When the expansion piston 16 starts to rise and the compression piston 13 retracts, the low temperature refrigerant gas passes through the regenerator 4 and returns to the compression space 11 through the gas flow path 5. At this time, in the regenerator 4, the regenerator material is cooled and cold heat is stored in the regenerator 4.

One thermal cycle is completed by the above steps, and this step is repeated by the reciprocating movement of the crank mechanism 24 of the crank mechanism section 9. As a result, the temperature of the freezing generator 17 and the temperature of the regenerator 4 gradually drop,
The refrigerant gas in the freezing generation unit 17 is set to a low temperature. In this state, in the freezing take-out unit 8, the cold heat of the freezing generation unit 17 is exchanged with an external low temperature tank as a heat utilization unit (not shown) to bring the cooling load of the external low temperature tank to the freezing temperature.

[0016]

However, in the conventional Stirling refrigerator 1 described with reference to FIG. 4, the lubricating oil 23 in the crank chamber 22 is moved from the seal portions of the guide portions 20 and 21 to the gas compressor as an operating space. 2 and expander 3
However, there is a problem that the refrigerating capacity is deteriorated by being mixed with and.

Conventionally, in the gas compressor 2, the crank mechanism 2 is used.
The connecting rod 25 extending from
No. 0 guide receiver 20a is slidably fitted to the cross guide 26, and the piston rod 27 of the cross guide 26 penetrates through the through hole 20b. The piston rod 27 is provided with an oil seal 33, and the compression piston 13 It is attached to the rear of the.

With this structure, the crank motion of the crank mechanism 24 is converted into the reciprocating motion of the compression piston 13, and
The lubricating oil 23 in the crank chamber 22 is prevented from entering the space 32 behind the compression piston 13.

However, it is difficult to completely seal the lubricating oil 23 with only the oil seal 33, and the lubricating oil 23 enters the space 32 at the rear. Therefore, there is a problem that the invading lubricating oil 23 mixes with the refrigerant gas to reduce the refrigerating capacity, and mixes with the regenerator material of the regenerator 4 to deteriorate the regenerator capacity.

The above is the compression piston 1 of the expander 3.
The same applies to 3 and the guide portion 21.

[0021] Therefore, it is an object of the present invention to provide a refrigeration system in which mixing of lubricating oil into the working space is extremely effectively prevented.

[0022]

According to a first aspect of the present invention, a compression space compressed by a compression cylinder and an expansion space expanded by an expansion cylinder communicate with each other through a flow path through a regenerator, and the compression cylinder. The compression piston of the expansion cylinder and the expansion piston of the expansion cylinder are connected to a drive motor via a crank mechanism so that they are reciprocally driven with a predetermined phase difference from each other, and the refrigerant gas guided from the compression space to the expansion space In a refrigerating apparatus that generates a low temperature by a heat cycle including an expansion process, the other ends of connecting rods extending from cranks of the crank mechanism unit are rotatably connected to corresponding cross guides, respectively, Each said compression piston or expansion by a piston rod extending from the guide The cross guide is slidably fitted to a bearing tube that is connected to the rear part of the stone and is fitted in a guide recess formed in the guide part for guiding the cross guide, and the bottom part of the guide recess is Has an oil-repellent portion for preventing adhesion of lubricating oil, and further has a through hole through which the piston rod penetrates from the bottom of the guide recess toward the compression cylinder or the expansion cylinder, and through which an oil seal is provided. It was done so.

According to a second aspect of the present invention, the compression space compressed by the compression cylinder and the expansion space expanded by the expansion cylinder communicate with each other through the flow path through the regenerator, and the compression piston of the compression cylinder and the expansion A thermal cycle including an expansion process of a refrigerant gas, which is connected to a drive motor through a crank mechanism so that the expansion piston of the cylinder and the expansion piston are reciprocally driven with a predetermined phase difference, and which is guided from the compression space to the expansion space. In the refrigerating apparatus for generating a low temperature by the above, the other ends of the connecting rods extending from the cranks of the crank mechanism section are rotatably connected to the corresponding cross guides, and further extended from the cross guides. A piston rod connects to the rear of the compression piston or expansion piston, respectively. On the other hand, the cross guide is slidably fitted to a bearing cylinder in which an oil return groove for returning lubricating oil that fits in a guide recess formed in a guide portion for guiding the cross guide is formed. Further, the piston rod penetrates from the bottom of the guide recess toward the compression cylinder or the expansion cylinder, and a through hole with an oil seal is formed.

[0024]

According to the invention of claim 1, since the oil repellent portion for preventing the adhesion of the lubricating oil is provided on the bottom of the guide receiving recess of the guide portion, the lubricating oil is compressed or expanded through the compression piston or the expansion piston. Mixing into the working space of the cylinder is prevented. Therefore, deterioration of the cold storage capacity and deterioration of the heat exchange capacity can be avoided, and the refrigeration capacity can be maintained.

According to the second aspect of the present invention, the oil return groove for returning the lubricating oil that has entered the guide receiving concave portion of the guide portion is formed in the bearing cylinder fitted in the guide receiving concave portion. It is prevented from entering into the working space of the compression cylinder or the expansion cylinder via. Therefore, deterioration of the cold storage capacity and deterioration of the heat exchange capacity can be avoided, and the refrigeration capacity can be maintained.

[0026]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic view of a lubricating oil seal mechanism portion provided in a Stirling refrigerator 1 showing a first embodiment of the present invention. The same reference numerals as those in FIG. 4 showing the conventional example indicate the same or corresponding portions, and each portion other than the portion shown in FIG. 1 has substantially the same configuration as that of FIG. 4. In this embodiment, the gas compressor 2 is used.
An example in which the lubricating oil seal mechanism portion 37 is applied to the compression cylinder 12 side will be described.

In the figure, the lubricating oil seal mechanism portion 37 is formed in the guide portion 20, and the guide portion 20 has a cylindrical shape and is hollow in which a cross guide 26 is fitted in the rear portion and a bearing cylinder 38 which is slidable is fitted therein. Guide receiving recess 20a is formed, and
A through hole 20b is formed which communicates with the guide receiving recess 20a and through which the piston rod 27 connected to the cross guide 26 penetrates. Two recesses 20c are formed in the middle of the through hole 20b. Seal 33
Has been applied.

The bottom 20a1 of the guide receiving recess 20a
An oil repellent portion 39 is formed on the. As the oil-repellent portion 39, for example, a thin film such as Teflon coat having a strong oil-repellent property is used and is applied or attached.

Reference numeral 26a is a gas vent hole for venting gas, and 40 is the cross guide 26 and the connecting rod 2.
5 shows a fastening tool that connects 5 with each other to make the connecting rod 25 rotatable.

With the above construction, the crank mechanism 24 is rotated by the drive motor as the drive source to perform the crank motion. Connecting rod 25 extended to the crank mechanism 24
Bearing tube 3 of the guide receiving recess 20a formed in the guide portion 20
8 reciprocally moves a cross guide 26 that is slidably fitted to the piston 8, and connects the cross guide 26 to a piston rod 27.
Causes the compression piston 13 to reciprocate.

As a result, the lubricating oil 23 filled in the crank chamber 22 is transmitted through the cross guide 26 and the like and is guided to the guide portion 2.
0 of the guide receiving recess 20a, and the lubricating oil 23 is moved along with the reciprocating movement of the cross guide 26 so that the bottom portion 2 of the guide receiving recess 20a.
It will be accumulated in 0a1. In this state, the lubricating oil 23 collected in the bottom portion 20a1 of the guide receiving recess 20a becomes the oil repellent portion 3a.
Bounced by 9.

Therefore, the lubricating oil 23 is prevented from entering the through hole 20b of the guide portion 20, and even if the lubricating oil 23 enters the through hole 20b of the guide portion 20, the oil seal 33 provides a space. Intrusion into 32 is prevented.

Thus, the bottom 20 of the guide receiving recess 20a is
Since the lubricating oil 23 that has entered a1 is repelled by the oil repellent portion 39, it is possible to prevent the lubricating oil 23 from entering the gas compressor 2 side as the operating space.

Therefore, the refrigerating capacity of the Stirling refrigerator 1 can be prevented from deteriorating due to the penetration of the lubricating oil 23 into the gas compressor 2, and the lubricating oil 23 can be prevented from entering the regenerator 4 and the regenerator capacity of the regenerator material can be improved. The drop can be avoided. In addition,
In the first embodiment, the gas compressor 2 is provided with the lubricating oil seal mechanism portion 3
Although the example in which No. 7 is applied has been described, the lubricating oil seal mechanism unit 37 can be applied to the expander 3 in the same manner.

FIG. 2 is a schematic view of a lubricating oil seal mechanism portion provided in a Stirling refrigerator 1 showing a second embodiment of the present invention.

The same reference numerals as those in FIG. 4 showing the conventional example indicate the same or corresponding portions, and each portion other than the portion shown in FIG.
The configuration is almost the same as that of FIG. 4, and an example in which the lubricating oil seal mechanism portion 41 is applied to the compression cylinder 12 side of the gas compressor 2 will be described.

In the figure, the lubricating oil seal mechanism section 41 is
The guide portion 20 is formed in a cylindrical shape, and the guide portion 20 has a cylindrical shape and a hollow guide receiving concave portion 20a into which a bearing sleeve 42 on which the cross guide 26 is slidably fitted is fitted. A through hole 20b through which a piston rod 27 that communicates with the cross guide 26 and penetrates is formed, two recesses 20c are formed in the middle of the through hole 20b, and an oil seal 33 is provided on these recesses 20c. ing.

Then, the bearing sleeve 42 fitted to the guide portion 20.
As shown in the sectional view of FIG. 3, an oil return groove 42a is provided in the lower portion, and the oil return groove 42a is inclined with a height difference from the bottom 20a1 of the guide receiving recess 20a to the opening 20a2. Further, the cross guide 26 is provided with a gas vent hole 26a, and an oil vent hole 26b is formed below the cross guide 26.

Reference numeral 40 denotes a fastening tool which connects the cross guide 26 and the connecting rod 25 to make the connecting rod 25 rotatable.

In the above structure, when the crank mechanism 24 is rotated by the drive motor as the drive source to perform the crank motion, the connecting rod 2 extended to the crank mechanism 24 is connected.
The piston rod 2 is connected to the cross guide 26 by reciprocating the cross guide 26, which is slidably fitted in the bearing sleeve 42 of the guide receiving recess 20a formed in the guide portion 20.
7, the compression piston 13 is reciprocated.

As a result, the lubricating oil 23 filled in the crank chamber 22 is transmitted through the cross guide 26 and the like to the guide portion 2.
No. 0 guide receiving recess 20a will be collected in the bottom portion 20a1.

In this state, the lubricating oil 23 collected in the bottom portion 20a1 of the guide receiving concave portion 20a travels through the oil return groove 42a formed in the bearing sleeve 42 and the opening 2 of the guide receiving concave portion 20a.
It is returned to the 0a2 side.

Further, the lubricating oil 23 accumulated around the cross guide 26 has an oil drain hole 2 formed in the cross guide 26.
6b, the oil return groove 42a formed in the bearing sleeve 42
And is returned to the crank chamber 22 from the opening 20a2 of the guide receiving recess 20a. Further, even if the lubricating oil 23 enters the through hole 20b of the guide portion 20, the oil seal 3
3 prevents entry into the space 32.

Thus, the bottom portion 20 of the guide receiving recess 20a is
The lubricating oil 23 that has entered the a1 is the oil return groove 42 of the bearing sleeve 42.
Since it is returned to the crank chamber 22 through the a, it is possible to prevent the lubricating oil 23 from entering the gas compressor 2 side as the working space.

In the second embodiment, the example in which the lubricating oil seal mechanism portion 41 is applied to the gas compressor 2 has been described, but the same can be performed by applying the lubricating oil seal mechanism portion 41 to the expander 3. it can.

[0047]

As described above, according to the invention of claim 1, since the oil repellent portion for preventing the adhesion of the lubricating oil is provided at the bottom of the guide receiving concave portion of the guide portion, the lubricating oil is a compression cylinder or an expansion cylinder. Is prevented from being mixed into the working space. Therefore, deterioration of the cold storage capacity and deterioration of the heat exchange capacity can be avoided, and the refrigeration capacity can be maintained.

According to the second aspect of the present invention, since the oil return groove for returning the lubricating oil is formed in the bearing cylinder fitted in the guide receiving recess, the lubricating oil is passed through the compression piston or the expansion piston.
Mixing into the working space of the compression or expansion cylinder is prevented. Therefore, deterioration of the cold storage capacity and deterioration of the heat exchange capacity can be avoided, and the refrigeration capacity can be maintained.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a main part of a lubricating oil seal mechanism portion included in a Stirling refrigerator showing a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of a main part of a lubricating oil seal mechanism portion included in a Stirling refrigerator showing a second embodiment of the present invention.

FIG. 3 is a sectional view of a bearing sleeve fitted in the guide receiving recess of FIG.

FIG. 4 is a schematic diagram of a conventional Stirling refrigerator.

[Explanation of symbols]

1 Stirling refrigerator 2 gas compressor 3 expander 4 regenerator 5 gas flow paths 6 radiator 7 radiator 8 Freezing section 9 Crank mechanism 10 Compression cylinder body 11 compression space 12 compression cylinders 13 compression piston 20 Information Department 20a Guide receiving recess 20b through hole 21 Information Department 22 Crank chamber 23 Lubricating oil 24 crank mechanism 25 connecting rod 26 Cross Guide 26b Oil drain hole 27 Piston rod 28 Connecting Rod 29 Cross Guide 30 piston rod 32 spaces 33 Oil seal 35 space 36 Oil seal 37 Lubricating oil seal mechanism 38 Bearing tube 39 Oil repellent part 40 Fastener 41 Lubricating oil seal mechanism 42 Bearing tube 42a Oil return groove

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-64-87854 (JP, A) JP-A-61-79848 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) F25B 9/14 510 F02G 1/053

Claims (2)

(57) [Claims] 1. A compression space compressed by a compression cylinder and an expansion space expanded by an expansion cylinder communicate with each other through a flow path through a regenerator, and the compression piston of the compression cylinder and the expansion piston of the expansion cylinder. Are connected to a drive motor through a crank mechanism so that they are reciprocally driven with a predetermined phase difference from each other, and generate a low temperature by a heat cycle including an expansion process of a refrigerant gas guided from the compression space to the expansion space. In the refrigeration system, the other ends of the connecting rods respectively extended from the cranks of the crank mechanism section are rotatably connected to the corresponding cross guides, and further, by the piston rods extended from the cross guides. While connected to the rear of the compression or expansion piston, The cross guide is slidably fitted in a bearing tube that is fitted in a guide recess formed in a guide portion for guiding the loss guide, and the bottom of the guide recess has a repellency that prevents adhesion of lubricating oil. An oil portion is formed, and further, the piston rod penetrates from the bottom of the guide recess toward the compression cylinder or the expansion cylinder, and an oil-sealed through hole is formed. apparatus. 2. A compression space compressed by the compression cylinder and an expansion space expanded by the expansion cylinder communicate with each other through a flow path through a regenerator, and the compression piston of the compression cylinder and the expansion piston of the expansion cylinder. Are connected to a drive motor through a crank mechanism so that they are reciprocally driven with a predetermined phase difference from each other, and generate a low temperature by a heat cycle including an expansion process of a refrigerant gas guided from the compression space to the expansion space. In the refrigeration system, the other ends of the connecting rods respectively extended from the cranks of the crank mechanism section are rotatably connected to the corresponding cross guides, and further, the piston rods are extended from the cross guides respectively. While connected to the rear of the compression or expansion piston, the front The cross guide is fitted slidably in a bushing that oil return groove is formed to return the lubricating oil to be fitted in the guide recess formed in the guide portion for guiding the cross guide,
Further, the refrigerating apparatus is characterized in that the piston rod penetrates from the bottom of the guide recess toward the compression cylinder or the expansion cylinder, and a through hole with an oil seal is formed.