JPH02154950A - Stirling refrigerator - Google Patents

Abstract

PURPOSE:To make a refrigerator small in size and light in weight and reduce the power consumption of the Stirling refrigerator of which the refrigerant gas is charged in a pressure vessel, by a method wherein compressing cylinders are provided on the both ends of the pressure vessel in the direction of a movable contact of a linear motor, pistons are mounted on the both ends of a spindle attached to the movable contact, and the compressing cylinders are connected to displacers. CONSTITUTION:When a linear motor 20 is driven by supplying opposite AC current to coils 26 and 28, a movable contact 18 is reciprocated corresponding to the frequency of AC current, causing pistons 38a and 38b attached to the both ends of a spindle 36 to reciprocate in cylinders 14a and 14b, so that the helium gas in the compressing cylinders is compressed alternatively. The compressed helium gas is led into displacers 12a and 12b through paths 40 and 42, and cooled by adiabatic expansion in cooling chambers of the displacers. Therefore, as one linear motor is able to drive two or more cylinders, a Stirling refrigerator having multiple cooling systems can be made small in size and light in weight with reduced power consumption.

Description

[Detailed Description of the Invention] Summary Regarding the drive mechanism of the compression section in a Stirling refrigerator, an object of the present invention is to provide a Stirling refrigerator in which the drive mechanism of the compression section is smaller and lighter, and the power consumption is reduced. A stator of a linear motor is installed in a pressure vessel defining a compression cylinder, a piston attached to a movable element of the linear motor is reciprocated in the compression cylinder, and the inside of the compression cylinder is connected to a displacer via a passage. In a Stirling refrigerator which communicates with each other and seals refrigerant gas in the pressure vessel, compression cylinders are provided on both sides of the pressure vessel in the moving direction of the mover, a shaft extending in the moving direction is attached to the mover, and the Pistons are provided at both ends to reciprocate within the compression cylinders, and each compression cylinder is configured to communicate with an independent displacer via a passage.

INDUSTRIAL APPLICATION FIELD The present invention relates to a Stirling refrigerator, and more particularly to a drive mechanism for a compression section in a Stirling refrigerator.

A Stirling refrigerator, which compresses a refrigerant such as helium gas with a piston and introduces it into a cooling chamber, and cools the refrigerant by adiabatic expansion, is known for its high cooling efficiency and ability to cool to a very low temperature. Stirling refrigerators with multiple refrigeration systems require the same number of compression pistons as refrigeration systems, which complicates the drive mechanism.
There is a demand for a smaller and lighter drive mechanism for the compression section.

Conventional technology The drive mechanism of the compression section in a conventional Stirling refrigerator employs a rotary motor as the drive source, converts rotational motion into linear motion using a crank mechanism, and compresses helium gas sealed in with a piston. was. However, a drive mechanism that uses a rotary motor like this has problems such as vibrations, pistons that are difficult to move straight, and sealed helium gas that is easily contaminated by bearing grease. The present inventors previously developed a Stirling refrigerator using a linear motor as a drive mechanism. In this Stirling refrigerator, one linear motor was used to drive one compression piston.

Problems to be Solved by the Invention This has led to problems such as an increase in the size of the drive mechanism, an increase in weight, and an increase in power consumption.

The present invention has been made in view of these points, and an object thereof is to provide a Stirling refrigerator in which the drive mechanism of the compression section is smaller and lighter, and the power consumption is reduced.

Means for Solving the Problems A stator of a linear motor is mounted in a pressure vessel having a compression cylinder defined at its end, a piston attached to a movable part of the linear motor is reciprocated in the compression cylinder, and In a Stirling refrigerator whose interior is connected to a displacer via a passage and a refrigerant gas is sealed in a pressure vessel, compression cylinders are provided on both sides of the pressure vessel in the moving direction of the movable element. A shaft extending in the moving direction of the mover is attached to the mover, and pistons that reciprocate within the compression cylinder are provided at both ends of the shaft, and
Each compression cylinder communicates with an independent displacer via a passageway.

Since the pistons are connected to both sides of the shaft attached to the working mover, it is possible to cool at least two refrigeration systems with one linear motor.

Therefore, it is possible to reduce the size and weight of the drive mechanism in the compression section of the Stirling refrigerator and reduce power consumption.

Example Embodiments of the present invention will be described in detail below based on the drawings.

FIG. 1 is a sectional view of an embodiment of the invention. The Stirling refrigerator shown in FIG. 1 is composed of one compression section 10 and two displacers 12a and 12b forming refrigeration sections. 14 is a pressure vessel, and two compression cylinders 14a and 14b are formed on both sides thereof. A linear motor 20 composed of a stator 16 and a movable element 18 is provided within the pressure vessel 14 . The stator 16 is
A yoke 22 made of soft magnetic material fixed to the inner surface of the pressure vessel 14
and two annular coils 26 and 28 provided inside this yoke 22. The coils 26 and 28 are wound in the same direction on the bobbin 24, and when driven, the coils 26 and 28 are driven by passing current in opposite directions.

On the other hand, the mover 18 is constructed by fixing two annular permanent magnets 32 and 34 on a yoke 30 made of soft magnetic material, and a shaft 36 is fixed to the yoke 30 by, for example, welding. At each end of the shaft 36 are respective compression cylinders 148.14b.
Pistons 38a, 38b are attached to reciprocate within. The inside of the compression cylinder 14a is communicated with the displacer 12a via the passage 40, and the compression cylinder 1
The interior of the displacer 4b is communicated with the displacer 12b via a passage 42. Helium gas, which acts as a refrigerant, is sealed inside the pressure vessel 14.

When the linear motor 20 is driven by passing an alternating current in the opposite direction through the coils 26 and 28, the movable element 18 reciprocates left and right according to the frequency of the alternating current, and the piston 38a fixed to both ends of the shaft 36 moves. , 38b reciprocate within the compression cylinders 14a, 14b to alternately compress the helium gas within the compression cylinders. Compressed helium gas passes through passages 40.42 to displacers 12a, 1.
2b and is cooled by adiabatic expansion within the cooling chamber of the displacer.

FIG. 2 shows a sectional view of the displacer, in which a hollow piston 46 made of resin is fitted into a cylinder 44 made of SUS so as to be able to reciprocate. cylinder 44
The piston 46 has a hole 44a that communicates the inside of the cylinder with the passage 40, and the piston 46 has a hole 4a that communicates the inside of the piston with the passage 40 through a hole 44a provided in the cylinder.
6a is provided. A hole 46 at the top of the piston 46
b is formed. Furthermore, a regenerator 48 is built inside the piston 46 . The regenerator 48 is made of, for example, SUS.
It is made of metal wire mesh and performs heat exchange of helium gas. Two annular seals 50 and 52 are provided in the piston 46 to surround the hole 46a, and prevent the helium gas supplied through the passage 40 from passing between the cylinder 44 and the piston 46. However, all the helium gas is supplied into the piston 46 through the holes 44a and 46a. A spring 54 is provided at the bottom of the piston 46, and the pressure of the helium gas introduced into the cooling chamber 56 and the spring force of the spring 54 cause resonance to cause the piston 46 to reciprocate within the cylinder 44. I have to. By appropriately selecting the spring constant of the spring 54, etc., the phase of the piston 46 is set to be 90 degrees ahead of the phase of the piston 38a in the compression cylinder 14a. 58 is, for example, HgCd
This is an infrared sensor made of Te, and its sensitivity is fully demonstrated by cooling it below the liquid nitrogen temperature.

The compressed helium gas introduced through the passage 40 flows through the hole 4
4a and 46a into the interior of the piston 46,
After being cooled by a certain amount of heat exchange in the regenerator 48, it is introduced into the cooling chamber 56 where it is compressed by the piston 46. Since the piston 46 reciprocates up and down at a frequency of about 15 Hz, for example, the piston 46 descends at the next moment and the helium gas in the cooling chamber 56 expands.

Since this is an adiabatic expansion, the helium gas in the cooling chamber 5G is rapidly cooled. By repeating this cycle, the inside of the cooling chamber 56 is cooled to, for example, about 30°C, and the infrared sensor 58 mounted on the cylinder 44 can be cooled to a temperature below the liquid chamber S temperature.

As mentioned above, in this embodiment, pistons are provided at both ends of the shaft attached to the mover of the linear motor, and one linear motor drives two pistons, and these pistons alternately supply helium gas. Since it is configured to compress, a Stirling refrigerator having two cooling systems can be constructed using one linear motor. In addition, the reaction force caused by one compression of one piston can be used to compress the other piston, so the linear motor can be
It is possible to reduce power consumption compared to the case where only one is used.

FIG. 3 is a sectional view of another embodiment of the invention.

In this embodiment, a piston 38b is attached via a link mechanism 62 to one side of a shaft 60 fixed to the movable element 18 of the beam near motor. One end of the shaft 60 is bifurcated, and members 60a and 60b are integrally formed. The piston 38b is attached to the link 64, and the link 64
and member 60a.

60b via links 66a and 66b as follows.

That is, the links 66a, 66b connect the bottles 76a, 76 to the support members 70a, 70b fixed to the pressure vessel 14, respectively.
b, and the link 66a is a bin? 2a is rotatably attached to the member 60a, a pin 74 is rotatably attached to the link 64, and the link 66b is rotatably attached to the member 60a. 2b is rotatably attached to member 60b, and pin 74 is rotatably attached to link 64. link 66a
and 66b are formed with long holes at both ends, and pins 72a, 72b, and 74 are inserted into these long holes, and these long holes are designed to absorb deformation of the link mechanism 62 when the shaft 60 moves. I have to.

According to this embodiment, the links 66a and 66b are connected to the bin 76a.
, 76b as fulcrums, the two pistons 38a, 38b move in opposite directions, making it possible to reduce vibrations in the compression section of the Stirling refrigerator.

In the two embodiments described above, one piston is fixed to each end of the shaft of the mover of the linear motor, but a plurality of pistons may be fixed to both ends of the shaft. Also good.

Effects of the Invention Since the Stirling refrigerator of the present invention is configured as detailed above, it is possible to operate multiple pistons in the compression section with one linear motor. This has the effect of contributing to making the refrigerator smaller and lighter and reducing power consumption.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of an embodiment of the present invention, FIG. 2 is a cross-sectional view of a displacer, and FIG. 3 is a cross-sectional view of another embodiment of the present invention. 10... Compression part, 12a, 12b... Displacer, 14a, 14b
...compression cylinder, 16... stator, 18... mover, 20...
...Linear motor, 22.30...Yoke, 26.28...Coil, 32.34...Permanent magnet, 36.60...Shaft, 38a, 38b-...Piston, 62... link mechanism. +2a,! 2b Tice 7° rape 14a, j
4b: Leg Yata Shil)ng 16 Kojiko 18: Possible f2I-) ・Linear motor

Claims (1)

[Claims] A stator (16) of a linear motor is installed in a pressure vessel (14) defining a compression cylinder at its end, and a piston attached to a movable element (18) of the linear motor is inserted into the compression cylinder. In a Stirling refrigerator, the compression cylinder is communicated with a displacer through a passage, and a refrigerant gas is sealed in the pressure vessel. A cylinder (14a, 14b) is provided, and the mover (18) is provided with a shaft (36, 14b) extending in the direction of movement thereof.
60), and the compression cylinder (14) is attached to both ends of the shaft (36, 60).
pistons (38a, 38) that reciprocate within
b), and a passage (14a, 14b) is provided inside each compression cylinder (14a, 14b).
40, 42) via an independent displacer (12a
, 12b), respectively.