JPH07260278A - Stirling refrigerator - Google Patents

Abstract

PURPOSE:To eliminate the source of vibration from a stirling refrigerator, since it has been discovered that a relation exists between the refrigerating capacity of a stirling refrigerator and the presence or absence of vibration, so as to improve the refrigerating capacity. CONSTITUTION:A crank shaft 14 which reciprocates a compression piston and an expansion piston 4 is partly formed as a rotary shaft 14' of a motor (16) so that the crank shaft 14 and the rotary shaft 14' are formed in one solid piece.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a Stirling refrigerator with reduced vibration.

[0002]

2. Description of the Related Art A Stirling refrigerator, as shown in FIG. 3, includes a compression piston 2 which reciprocates in a compression cylinder 1,
And an expansion piston 4 which reciprocates in the expansion cylinder 3. The compression piston 2 forms a compression space 5 in the compression cylinder 1, the expansion piston 4 forms an expansion space 6 in the expansion cylinder 3, and the two spaces 5, 6 are connected via a radiator 7, a regenerator 8 and a cold head 9. To connect. The compression piston 2 and the expansion piston 4 are connected to the crankshaft 10, and the crankshaft 10 causes the pistons 2 and 4 to reciprocate with a predetermined phase difference (for example, 90 degrees). The rotation of the crankshaft 10 is performed by keying the output shaft 11 of the induction motor (M) to the crankshaft 10.

Crankshaft 10 of both pistons 2, 4
The reciprocating motion by means of which the working gas is subjected to isothermal compression, isovolumetric expansion, isothermal expansion and isovolumeic stroke, and it becomes possible to obtain the refrigerating output by the cold head 9.

[0004]

The refrigerating capacity of the Stirling refrigerator is to prevent leakage of the working gas without fail.
Stabilization and improvement are expected, and further, a desired refrigeration cycle can be performed by efficiently performing necessary heat transfer, and an extremely low temperature can be output in a stable form. For this reason, many proposals have been made regarding improvements to the seal and materials of each component.

[0005] For example, even if a Stirling refrigerator is manufactured which enables an output at an extremely low temperature of 70K in view of seal leakage and heat transfer loss, the design value of 70K cannot be obtained, and the freezing loss is reduced. The reality is that we are designing and manufacturing a Stirling refrigerator with a few percent expected. It was assumed that such a substantial decrease in refrigeration capacity was due to the presence of seal leakage and heat transfer loss. The inventors hypothesized that the substantial decrease in the refrigerating capacity as described above may be caused by the vibration and resonance of the Stirling refrigerator, and tried to improve the refrigerating capacity from the vibration countermeasures. . Therefore, an object of the present invention is to improve the refrigerating capacity of the Stirling refrigerator by effective countermeasure against vibration.

[0006]

The present inventors have found that the largest cause of vibration in a Stirling refrigerator is the joint between the output shaft of the motor and the crankshaft, and the joint is made non-vibrating. However, the most effective means selected from many attempts has been to use a part of the crankshaft as the output shaft of the motor.

Therefore, the present invention reciprocates in a compression piston that reciprocates in the compression cylinder and forms a compression space in the compression cylinder that encloses the working gas, and reciprocates in the expansion cylinder with a cold head and operates the working gas. The expansion piston that forms an expansion space that encloses the expansion cylinder, the radiator and the regenerator that are arranged in the circuit that connects the compression space and the expansion space, and the compression piston and the expansion piston reciprocate with a predetermined phase difference. Provided is a Stirling refrigerator having a crankshaft for driving, and a motor having a part of the crankshaft as an output shaft.

[0008]

The rotary motion of the motor directly rotates the crankshaft, and no vibration occurs. The output shaft of the motor and the center of rotation of the crankshaft coincide with each other, so that there is no unnecessary load on the motor and the power consumption can be reduced.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of the present invention is shown in FIGS. 1 and 2, and the same reference numerals are given to the portions corresponding to the example of FIG. A compression piston 2 is arranged in a bore in the compression cylinder 1 to form a compression space 5. An expansion piston 4 is arranged in an expansion cylinder 3 connected to the compression cylinder 1 to form an expansion space 6. A radiator 7 and a regenerator 8 are arranged in a passage 12 connecting the two spaces 5, 6. Reference numeral 9 is a cold head 9 that takes out an extremely low temperature to the outside. The compression piston 2 is connected to the crankshaft 14 via a rod 13, and the expansion piston 4 is connected to the crankshaft 14 via a rod 15. In this example, the phase difference between the pistons 2 and 4 is 90 degrees in angle.
The motor 19 has a rotating shaft 14 ′, which is an extension of a part of the crankshaft 14, a permanent magnet 16 around the rotating shaft 14 ′, and a coil portion 18 wound around a fixed iron core 17. A bearing 18 supports the end portion of the crankshaft 14 and the rotary shaft 14 'integral therewith.

When the motor 19 is energized, the rotary shaft 14 'and the crankshaft 14 integral therewith are rotated, the pistons 2 and 4 are reciprocated at a predetermined phase angle, and the cold head 9 is rotated.
Get a much lower temperature. Rotating shaft 14 'and crankshaft 1
Since 4 and 1 were integrated, the occurrence of vibration in this part was eliminated, and it was confirmed that the refrigerating capacity was improved.

[0011]

[Effect] Since there is no joint between the theta rotation shaft and the crankshaft, the rotation of the crankshaft is not delayed with respect to the rotation shaft, smooth rotation is obtained, and output fluctuations are eliminated. Further, since the seam is unnecessary, the diameter of the rotary shaft can be increased regardless of the diameter of the crankshaft, so that the output torque can be increased. Further, since the bearing can be arranged at the portion corresponding to the joint, it becomes easy to support the rotating portion.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a refrigerator according to an example of the present invention.

FIG. 2 is a sectional view taken along the line II-II of FIG.

FIG. 3 is a diagram showing a basic configuration of a Stirling refrigerator.

[Explanation of symbols]

 1, 3 Cylinder 2, 4 Piston 5 Compression space 6 Expansion space 7 Radiator 8 Regenerator 9 Cold head 14 Crankshaft 14 'Rotating shaft 16 Motor

Claims (1)

[Claims] 1. A compression piston that reciprocates in a compression cylinder and forms a compression space in which a working gas is enclosed, and an expansion space that reciprocates in an expansion cylinder with a cold head and that contains a working gas. An expansion piston formed in the expansion cylinder, a radiator and a regenerator arranged in a circuit connecting the compression space and the expansion space, and a crankshaft that reciprocates the compression piston and the expansion piston with a predetermined phase difference, And a Stirling refrigerator having a motor having a crankshaft as an output shaft.