JP3717812B2 - Stirling refrigerator oil seal bellows - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a Stirling refrigerator, and more particularly, to an oil seed bellows that prevents oil from rising from a crank chamber of a Stirling refrigerator into a compression cylinder or an expansion cylinder.
[0002]
[Prior art]
In recent years, it has been used as a refrigeration device in place of CFCs for global environmental problems and has a wider operating temperature than conventional refrigeration equipment. Application to refrigeration equipment in all industrial fields such as liquid circulators, low temperature thermostats, thermostats, heat shock test equipment, freeze dryers, temperature characteristics test equipment, blood / cell storage equipment, cold coolers, and other various refrigeration equipment Stirling refrigerators are in the spotlight as possible refrigerators that are compact, have high coefficient of performance, and have good energy efficiency.
[0003]
In the Stirling refrigerator, there is a problem of so-called oil rise, in which oil and oil mist rise from the crank chamber along the piston rod. This oil rise adheres to the inner surface of the cylinder when oil or oil mist enters the cylinder, affecting the sealing performance of the piston ring, not only significantly reducing durability and reliability, but also with the compressed gas. It enters into the compressed gas utilization device at the air supply destination and adversely affects the compressed gas utilization device and various parts processed by the device.
[0004]
Conventionally, the piston rod is sealed with an oil ring seal in order to solve the problem of oil rising. This oil ring seal is generally made of rubber, and various developments have been made in terms of structure and material, but it cannot always be said that the sealing performance and durability are sufficient.
[0005]
Therefore, the present inventors have already proposed a bellows for oil seal (see Japanese Patent Application No. 10-365371) as a rod seal of a Stirling refrigerator. In the invention according to Japanese Patent Application No. 10-365371, a metal bellows for oil seal is provided between the space in the housing of the Stirling refrigerator and the compression cylinder and the expansion cylinder, and the crank is formed along the surface of the piston rod. This prevents oil from flowing into the compression cylinder and the expansion cylinder from the chamber.
[0006]
[Problems to be solved by the invention]
In the Stirling refrigerator, the present inventors have developed a configuration in which the oil seal bellows as described above is mounted and the life of the oil seal bellows is further improved. In addition, it has been found that repeated operation in the compression direction and extension direction is not necessarily desirable for repeated fatigue reduction.
[0007]
The object of the present invention is to prevent oil from rising in the Stirling refrigerator, to achieve an oil seal bellows with excellent sealing performance and long life, to improve the performance of the Stirling refrigerator, and to improve reliability and durability. is there. Then, this invention makes it a subject to implement | achieve the structure of the oil seal bellows which should aim at the lifetime improvement of an oil seal bellows based on the said knowledge.
[0008]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present invention provides a housing in which a motor and a crank are disposed, a cylinder fixed to the top of the housing, a piston that reciprocates in the cylinder, and a piston that interlocks with the crank. A Stirling refrigerator having a piston rod that is connected at one end to the housing and an oil seal bellows that seals between the housing and the cylinder, the tip of the oil seal bellows being located in the cylinder The piston or the piston rod is hermetically fixed, and the base end thereof is attached to the housing. The oil seal bellows is compressed from the free length position to the compression side, and again the free length It is mounted so as to perform a reciprocating movement of the stroke returning to the position. To provide a Stirling refrigerator.
[0009]
The oil seal bellows, the housing, and / or the compression cylinder and / or the expansion cylinder are applied.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings based on examples. 1-3 is a figure explaining the Stirling refrigerator to which this invention is applied, FIG. 1 is a front view explaining the whole structure of the Stirling refrigerator 1. FIG. FIG. 2 is a diagram for explaining a main part of the Stirling refrigerator 1, and FIG. 3 is a right side view partially showing a cross section.
[0011]
The housing 2 forming the main body of the Stirling refrigerator 1 is formed of a casting, and the inside thereof is kept in a hermetically sealed state and is filled with a working gas. The housing 2 includes a motor chamber 4 and a crank chamber 5 that communicate with each other via a partition wall 3. The motor chamber 4 is provided with a motor 6 capable of rotating in the forward and reverse directions. The crank chamber 5 is provided with a crankshaft 7 and connecting rods 8 and 9 which are driven to rotate by the motor 6 and cross guide heads 10 and 11. Etc. are arranged.
[0012]
The two crank portions 12 and 13 of the crankshaft 7 are formed with a phase difference so that the crank portion 13 moves ahead of the crank portion 12 when the motor 6 rotates forward. 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.
[0013]
A cylinder block 15 is attached to the upper portion of the crank chamber 5 in 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.
[0014]
A compression piston 19 reciprocates in the compression cylinder 17. An upper space (compression space) of the compression piston 19 in the compression cylinder 17 is a high temperature chamber 20, in which the working gas 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. An oil seal bellows 22 is attached between the compression piston rod 21 and the upper portion of the housing 2 to seal between the compression cylinder 17 and the crank chamber 5 and prevent oil from rising from the crank chamber 5.
[0015]
On the other hand, the lower part of the expansion cylinder 18 is composed of the cylinder block 15 as described above, and the upper part is composed of an inner cylinder 23 of a heat-dissipating heat exchanger 29 and an inner cylinder 24 of a cooling heat exchanger, which will be described later. ing. An expansion piston 25 reciprocates in the expansion cylinder 18, and a space (expansion space) above the expansion piston 25 in the expansion cylinder 18 is a low temperature chamber 26, in which the working gas expands and becomes a low temperature.
[0016]
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, and seals between the expansion cylinder 18 and the crank chamber 5 to prevent oil from rising from the crank chamber 5. The expansion piston 25 moves ahead of the compression piston 19 by a phase of 90 degrees.
[0017]
A heat dissipating heat exchanger (high temperature side heat exchanger) 29, a regenerator 30 and a cooling heat exchanger (low temperature side heat exchanger) 31 are arranged in an annular shape so as to surround the expansion cylinder 18. Yes. A manifold (flow channel for working gas) 32 is formed at the lower end of the heat exchanger 29 for heat dissipation and around the expansion cylinder 18.
[0018]
A communication hole 33 that communicates the high temperature chamber 20 and the manifold 32 is formed at the upper end of the compression cylinder 17. 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 dissipation heat exchanger 29, the regenerator 30, and the cooling heat exchanger 31.
[0019]
The cylinder block 15 has a heat exchange housing 34 for heat dissipation in the upper part thereof. A heat exchanger cylinder 37 is fitted between the heat-dissipating heat exchange housing 34 and the inner cylinder 23 to constitute a heat-dissipating heat exchanger (high temperature side heat exchanger) 29. The heat exchanger cylinder 37 has a narrow groove 35 that forms a flow path for the working gas on its inner surface, and a heat radiating fin 36 on its outer surface.
[0020]
The working gas passes through the narrow groove 35, and cooling water flows through the heat radiation path 38 between the heat radiating heat exchange housing 34 and the heat radiating fins 36, whereby heat of the working gas is radiated to the cooling water. A cover plate 39 is fixed in a watertight manner on both left and right side surfaces of the cylinder block 15, and a cooling water passage 40 is formed between the cover plate 39 and the cylinder block 15. The cooling water passage 40 is formed to surround the compression cylinder 17 and the expansion cylinder 18 while communicating with the heat radiation passage 38 through the inlet 41.
[0021]
A cooling water inlet 42 is provided in the heat radiation path 38, an outlet 43 is provided in the cooling water path 40, and the inlet 40 and the outlet 43 are not shown, but the cooling water circulation path and the cooling water circulation pump And is connected to an air-cooled radiator (radiator) having a cooling fan.
[0022]
The lower part of the inner cylinder 24 is fitted with the inner cylinder 23 to constitute a part of the expansion cylinder 18. A cooling heat exchange housing 44 is disposed on the outer periphery of the upper part of the inner cylinder 24, and the cylinder block 15. It is detachably fixed to. The cooling heat exchange housing 44 has a plurality of narrow grooves 45 on its inner surface, is fitted with the inner cylinder 24 to form a working gas flow path 46, and has cooling fins 47 on its outer surface. Thus, a cooling heat exchanger (low temperature side heat exchanger) 31 is configured.
[0023]
This cooling heat exchanger 31 cools the cold refrigerant of the cold-use equipment that uses the cold of the Stirling refrigerator of the present invention. Air, water, alcohol, HFE, PFC or the like is used as the cold heat refrigerant.
[0024]
In an annular space between the inner cylinder 24 and the cooling heat exchange housing 44, a regenerator 30 made of a cold storage material such as a metal mesh is disposed.
[0025]
A space between the oil seal bellows 28 and the expansion piston 25 (the same applies to the space between the oil seal bellows 25 and the compression piston 15) is called a buffer space (buffer chamber) 48. The buffer space 48 is connected to the buffer tank 51 by a pipe 49, and the buffer tank 51 is connected to the crank chamber 5 (or the motor chamber 4) of the housing 2 by a pipe 50.
[0026]
The present invention is characterized in that the following configuration is adopted in the Stirling refrigerator having the above-described configuration. In the Stirling refrigerator according to the present invention, a characteristic configuration is adopted for the compression-side and expansion-side oil seal bellows 22 and 28 attached as shown in FIG. FIG. 4 explains the present invention in comparison with the prior art for an oil seal bellows in a Stirling refrigerator, FIG. 4 (a) shows the present invention, and FIG. 4 (b) shows the prior art.
[0027]
The material of the oil seal bellows 22 and 28 used in the present invention may be a metal bellows formed by welding a SUS material, or may be a resin bellows integrally formed from a resin material.
[0028]
As shown in FIG. 2, the compression-side oil seal bellows 22 has a lower end portion 52 welded to an oil seal bellows fixing plate (hereinafter referred to as “fixing plate”) 53, and an upper end portion 54 attached to the oil seal bellows. It is welded to a plate (hereinafter referred to as “mounting plate”) 55. The oil seal bellows fixing plate 53 is fixed to the upper surface of the housing 2 by the seat portion 14. The mounting plate 55 is fixed to the compression piston 19 with a nut.
[0029]
As shown in FIG. 2, the expansion side oil seal bellows 28 has a lower end portion 56 welded to a fixed plate 53 and an upper end portion 57 attached to the mounting plate 55 in the same manner as the compression side oil seal bellows 22. It is welded. The oil seal bellows fixing plate 53 is fixed to the upper surface of the housing 2 by the seat portion 14. The mounting plate 55 is fixed to the large diameter portion 58 of the expansion piston rod 27 with a nut via a sleeve 59.
[0030]
The compression-side oil seal bellows 22 and the expansion-side oil seal bellows 28 reciprocate with their respective strokes according to the reciprocating strokes of the compression piston 19 and the expansion piston 18. The compression-side and expansion-side oil seal bellows 22 and 28 are not necessarily the same in diameter, free length, stroke, etc., but as shown in FIG. The reciprocation and stroke are conceptually shown. Here, in order to make the drawing easy to understand, the free length L and the stroke S include the thicknesses of the fixed plate 53 and the mounting plate 55.
[0031]
FIG. 4B shows the prior art. In the prior art, the total stroke S reciprocating is the same as the total stroke S according to the present invention, but a free length L ′ is used which is shorter than the free length L according to the present invention. Thereby, from the position of the free length L ′, the stroke moves to the compression side by the stroke S1 and the extension side by the stroke S2, and as a whole, reciprocates by the total stroke S.
[0032]
By the way, in the course of research and development of the Stirling refrigerator, the present inventors have repeatedly performed the reciprocating operation of the oil seal bellows. As shown in FIG. 4A, when the reciprocating operation is repeated by repeating the compression of the compression side stroke S1 and the expansion of the stroke S2 toward the expansion side, centering on the position of the free length, as shown in FIG. As described above, the present inventors have found that fatigue is greater than when the reciprocating operation is performed by compression to the compression side stroke S and return to the free length. The reason for this is considered to be that the force that repeatedly causes fatigue on the oil seal bellows acts more in the case of repeated compression and expansion / contraction than in the case of simple compression.
[0033]
Based on such knowledge, in the present invention, as shown in FIG. 4A, the oil seal has such a length that the reciprocating operation of the total stroke S can be performed only from the position of the free length L to the compression side. The bellows were prepared as the compression side oil seal bellows 22 and the expansion side oil seal bellows 28, respectively, and attached to the Stirling refrigerator 1 according to the present invention as shown in FIG.
[0034]
(Function)
Next, the operation of the Stirling refrigerator of the above embodiment of the present invention will be described. The crankshaft 7 is rotated in the forward direction by the motor 6, and the crank portions 10 and 11 in the crank chamber 5 are rotated 90 degrees out of phase. Through the connecting rods 8 and 9, the cross guide heads 19 and 11, the compression piston rod 17 and the expansion piston rod 23 connected to the crank portions 10 and 11, the compression piston 19 and the expansion piston 25 have a phase difference of 90 degrees from each other. Reciprocates.
[0035]
While the expansion piston 25 is moving 90 degrees ahead and slowly moving near the top dead center, the compression piston 19 rapidly moves near the middle toward the top dead center to compress the working gas. The compressed working gas flows through the communication hole 33 and the manifold 32 into the narrow groove 35 of the heat dissipation heat exchanger 29 and dissipates heat to the cooling water flowing through the heat dissipation path 38. Further, the working gas is cooled by the cold stored in the regenerator 30 and flows into the low temperature chamber 26 (expansion space) through the narrow groove 45.
[0036]
When the compression piston 19 is slowly moving near the top dead center, the expansion piston 25 is suddenly moved toward the bottom dead center, and the working gas flowing into the low temperature chamber 26 (expansion space) is rapidly expanded to generate cold heat. appear. As a result, a head portion (referred to as a cold head) 48 including the cooling heat exchanger 31 is cooled to a low temperature.
[0037]
Then, in the cooling heat exchanger 31, the cold refrigerant for the cold-use equipment 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 is moving from the intermediate position to the bottom dead center, and the working gas passes from the low temperature chamber 26 through the narrow groove 45 of the cooling heat exchanger and the regenerator. The refrigerating machine 30 stores the cold heat that flows into the working gas 30 and has the working gas. The cold stored in the regenerator 30 is reused to cool again the working gas sent from the high temperature chamber 20 through the heat dissipation heat exchanger 29 as described above.
0038
And the cold-heat refrigerant | coolant cooled in the heat exchanger for cooling is sent to the various cold-use equipment from the outflow pipe 60, and is utilized for cooling. For example, the cold heat refrigerant is sent to a cold heat refrigerant pipe in a cold energy utilization device such as a freezer and performs freezing or cooling action in the cold heat utilization device. Then, it is circulated back to the cooling heat exchanger 61 through the inflow pipe 63 from the cold energy utilization device and cooled again.
[0039]
Cooling water sent from a radiator (radiator) flows into the heat-dissipating heat exchanger 38 from the inlet 42 and passes through the heat-radiating path 38 to cool the working gas. Further, the 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. Thereafter, the cooling water flows out from the outlet 43, is cooled by the cooling fan in the radiator, and is circulated again to the heat exchanger 29 for heat radiation.
[0040]
The buffer tank 51 makes the buffer space 48 and the housing 2 have equal pressure, absorbs the pressure fluctuation in the buffer space 48, absorbs the pressure fluctuation in the housing 2, and does not affect the buffer space. It has a function.
[0041]
In the Stirling refrigerator 1 according to the present invention, as shown in FIG. 4 (a), reciprocating operation is performed by compression to the compression side stroke S and return to the free length, so that repeated fatigue acting on the oil seal bellows is performed. Less.
[0042]
The embodiments of the present invention have been described based on the examples. However, the present invention is not limited to the above-described examples, and various examples can be made within the scope of the technical matters described in the claims. Needless to say.
[0043]
【The invention's effect】
Since the present invention has the above-described configuration, the compression side and the expansion oil seal bellows perform a reciprocating operation by the stroke to the compression side and the return to the free length, thereby reducing the breaking force applied to the oil seal bellows. This can reduce repeated fatigue, prevent oil from rising in the Stirling refrigerator, and improve the life of the oil seal bellows.
[Brief description of the drawings]
FIG. 1 is a front view illustrating an entire 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 view of a partial cross section of the Stirling refrigerator of FIG.
FIG. 4 is a view for explaining an oil seal bellows of a Stirling refrigerator according to the present invention in comparison with the prior art.
[Explanation of symbols]
1 Stirling refrigerator 2 Housing 4 Motor chamber 5 Crank chamber 6 Motor 7 Crankshaft 14 Seat 15 Cylinder block 17 Compression cylinder 18 Expansion cylinder 19 Compression piston 20 High greenhouse 21 Compression piston rod 22 (Compression side) Oil seal bellows 25 Expansion piston 26 Low Greenhouse 27 Expansion Piston Rod 28 (Expansion Side) Oil Seal Bellows 29 Heat Dissipation Heat Exchanger 30 Regenerator 31 Cooling Heat Exchanger 34 (Cylinder Block) Heat Dissipation Heat Exchange Housing 40 Cooling Water Channel 48 Buffer Chamber 51 Buffer Tank 52 (compression side) lower end portion 53 of oil seal bellows 53 oil seal bellows fixing plate 54 (compression side) upper end portion of oil seal bellows 55 oil seal bellows mounting plate 56 (expansion side) lower end portion 57 of oil seal bellows (expansion side) Oy Lucille Bellows upper end 58 Expansion piston rod large diameter 59 Sleeve

Claims (2)

A housing in which a motor and a crank are disposed, a cylinder fixed to the top of the housing, a piston reciprocating in the cylinder, a piston interlocking with the crank and connected at one end to the piston and penetrating through the housing A Stirling refrigerator having an oil seal bellows for sealing between a rod and the housing and the cylinder,
The oil seal bellows has a tip hermetically fixed to the piston or the piston rod in the cylinder, and a base end attached to the housing.
The Stirling refrigerator, wherein the oil seal bellows is mounted so as to perform a reciprocating motion of a stroke in which a tip portion thereof is compressed from a free length position to a compression side and returned to the free length position again. The Stirling refrigerator according to claim 1, wherein the oil seal bellows is applied to either or both of a compression cylinder and an expansion cylinder.

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