JPH03294753A - Cryogenic temperature refrigerator - Google Patents

Abstract

PURPOSE:To effectively perform an operation and to easily decompose a driving mechanism and a displacer by detachably engaging the reciprocating shaft of the displacer with the axial center of a reciprocating drive shaft to be mechanically converted from the rotation of a motor. CONSTITUTION:A driving mechanism 5 has a motor 7 and a crank type rotary reciprocation converting mechanism 8 coupled to the motor 7. A cylinder 6 has a cylinder 9 for forming an outer cylinder and a displacer 11 for containing a cold storage unit 10. The displacer 11 is coupled to a reciprocating drive shaft 13 to be reciprocated, a coupling flange 15 is mounted at its head, a collar 16, an opening 17 are provided at the center, and the shaft 13 is integrated with the displacer 11. If the displacer 11 is removed, the mechanism 5 is laterally deviated at the initial of removal to disengage the collar 16 from a contraction part 14 to be easily disassembled.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a cryogenic refrigerator used for cooling superconducting coils, etc.

(Prior art) Cryogenic refrigerators, such as Gifford-McMuff on-cycle refrigerators, reciprocate a displacer with a built-in regenerator by a drive shaft of a drive mechanism consisting of an electric motor and a rotary reciprocating motion conversion mechanism. ing. The drive shaft of the drive mechanism section and the displacer are connected and move as one unit, so when performing maintenance such as replacing the seal attached to the displacer section, the drive mechanism section and displacer must be pulled out of the cylinder as a unit. There was a need. However, since the drive mechanism section is heavy and large, installation of the refrigerator is strongly restricted by the space for extraction during maintenance and workability.

There is also a method of reciprocating the displacer using gas pressure, but it is difficult to adjust the driving force from the gas pressure and the braking force from the friction of the seal, which can result in insufficient refrigerating capacity due to malfunction, or collision between the displacer and cylinder. It was easy to generate noise.

(Problems to be Solved by the Invention) In a refrigerator in which a displacer is reciprocated by gas pressure, it is not easy to operate the refrigerator reliably and without noise.

In refrigerators in which a displacer is operated by directly mechanically connecting an electric motor, installation of the refrigerator has been greatly influenced by issues such as work space and workability during maintenance.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to mechanically couple a displacer and an electric motor to ensure their operation, and also to enable easy disassembly of the drive mechanism section and the displacer section at the time of maintenance.

[Structure of the invention]

(Means for Solving the Problems) The cryogenic refrigerator of the present invention uses a refrigeration cycle that uses gas, a regenerator, and a displacer, and uses the displacer as an electric motor and mechanically converts the rotational motion of the electric motor into reciprocating motion. When the reciprocating shaft rotation of the displacer and the reciprocating drive shaft rotation of the drive shaft match when reciprocating by the drive shirt 1 of the drive mechanism section consisting of a rotary reciprocating motion converting mechanism, they fit together and the electric motor When the shaft centers are shifted from each other, the fitting is released, and the reciprocating drive shaft of the drive shaft connected to the electric motor and the reciprocating shaft of the displacer are separated.

(Function) In this way, by directly connecting and operating the displacer mechanically with an electric motor, the operation can be performed reliably and without noise, and the drive mechanism section and displacer section can be easily disassembled during maintenance. Since the heavy and large drive mechanism can be removed separately, less work space is required during maintenance, and the refrigerator can be installed in locations where workability is poor.

(Example) An example will be explained using a helium cryogenic refrigerator using the Gifford-McMuffon cycle.

FIG. 3 shows the appearance of the refrigerator. The refrigerator is
It is roughly divided into a compressor unit 2 and a cold head unit 3, and both are connected by a flexible gas hose 4.

FIG. 2 is a sectional view of this cold head unit 3. The cold head unit 3 has an upper drive mechanism section 5.
and a lower cylinder part 6.

The drive mechanism section 5 includes an electric motor 7 and a crank type rotation reciprocating motion conversion mechanism 8 connected to the electric motor 7.

The cylinder part 6 consists of a cylinder 9 forming an outer cylinder and a displacer 11 containing a regenerator 10 therein.

The displacer 11 reciprocates inside the cylinder 9,
The space between the two is sealed by a sliding seal 12 attached to the displacer 11. Note that the cylinder portion 6 has a two-tiered structure.

The displacer IJ is connected to the reciprocating drive shaft 13 of the rotary reciprocating exchange mechanism 8 and reciprocates.

As shown in FIG. 1, the reciprocating drive shaft 13 is provided with a constricted portion 14 near its tip. A connecting flange 15 is attached to the head of the displacer 11.
A flange 16 and an opening 17 are provided at the center of 5. When the rotational motion 18 of the reciprocating drive shaft 13 and the rotational motion 19 of the connecting flange 15 of the displacer 11 are made to match, the constriction portion 14 and the flange portion 16 fit together, and the reciprocating drive shaft 13 and the displacer 11 are integrated and operate. It becomes like this.

The sliding seals 12, 121 become worn and need to be replaced periodically. In this case, the drive mechanism section 5 is removed from the cylinder 9 and the displacer 11 is pulled out.
By shifting the drive mechanism section 5 in the lateral direction at the time of extraction, the flange section 16 and the constriction section 14 are disengaged, and the drive mechanism section 5 and the displacer 11 can be separated and disassembled easily.

By directly connecting and operating the displacer 11 mechanically with the electric motor 7, the operation can be performed reliably and without noise, and the drive mechanism section 5 and the displacer section 11 can be easily disassembled during maintenance, so the heavy and large drive Since the mechanism part 5 can be removed independently at the initial stage, the work space required for maintenance is small, and the refrigerator can be installed even in places where workability is poor.

(Other Embodiments) The refrigeration cycle does not have to be the Gifford-McMuffon cycle, but may be any refrigeration cycle that uses gas, a regenerator, and a displacer, such as a reverse Stirling cycle or a Solvay cycle.

The regenerator 10 does not need to be built into the displacer 11, and may be placed outside the cylinder.

The cylinder part 6 may have one stage or three or more stages.

The rotary reciprocating motion converting mechanism may be a rotary reciprocating motion converting mechanism using a cam or a Scotch choke other than a crank type.

The detailed structure of mating and separation is that when the reciprocating drive shaft, which mechanically converts the rotational motion of the reciprocating shaft of the displacer and the rotational motion of the electric motor into reciprocating motion, and the shaft center match, they mate and the electric motor reciprocates. Any material may be used as long as it is disengaged when the shaft centers are moved and the reciprocating drive shaft connected to the electric motor and the reciprocating shaft of the displacer are separated. The amount of lateral displacement required to unmate may be long or short.

〔Effect of the invention〕

In the cryogenic refrigerator of the present invention, the displacer and the electric motor are mechanically coupled to ensure reliable operation, and the drive mechanism section and displacer section can be easily disassembled during maintenance.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a coupling mechanism of a cryogenic refrigerator according to an embodiment of the present invention, FIG. 2 is a sectional view of a cold head unit of the above embodiment, and FIG. It is an external view of a low temperature refrigerator. 2...Compressor unit 1-3...Cold head unit 4...Flexible gas hose 5...Drive mechanism part 6...Cylinder part 7...
Electric motor 8... Rotation reciprocating motion conversion mechanism 9.91.
...Cylinder 10.101...Regenerator 11, 11
．． 1...Displacer 12, 121...Sliding seal 13...Reciprocating drive shaft 14...Constricted portion 15-Connecting flange 1
6... Flange 17... Openings 18, 19.
・Axis center

Claims (2)

[Claims] (1) In a cryogenic refrigerator that has a regenerator and a displacer and uses an electric motor to reciprocate the displacer, the axis of the reciprocating shaft of the displacer and the reciprocating drive shaft that mechanically converts the rotary motion of the electric motor into reciprocating motion A cryogenic refrigerator characterized by being removably fitted. (2) Claim (1) wherein the refrigeration cycle is a Gifford-McMaphon cycle, a Solvay cycle, a reverse Stirling cycle, or an improved version thereof.
The cryogenic refrigerator described.