JP2777198B2 - refrigerator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention relates to a refrigerator, and particularly to a refrigerator of the Gifford McMahon type.

(Prior Art) There are various types of cryogenic refrigerators. Among these is the Gifford McMahon type refrigerator. This refrigerator is generally configured as shown in FIG. This type of refrigerator is roughly composed of a cold head 1 and a refrigerant gas guide / discharge system 2. Cold head 1
It comprises a closed cylinder 3, a displacer 4, which is reciprocally housed in the cylinder 3, and a drive unit 40, which is arranged above the cylinder 3 and supplies the displacer 4 with power required for reciprocation. You. The inside of the cylinder 3 and the drive unit space 41 are isolated from each other by the seal mechanism 27 between the cylinder 3 and the drive unit 40.

The cylinder 3 includes a large-diameter first cylinder 5 and a small-diameter second cylinder 6 coaxially connected to the first cylinder 5.

A first-stage stage 7 as a cooling surface is constituted by a boundary wall portion between the first cylinder 5 and the second cylinder 6, and a second-stage stage 8 having a lower temperature than the first-stage stage 7 by a tip wall portion of the second cylinder 6. Is composed. The displacer 4 includes a first displacer 9 that reciprocates in the first cylinder 5,
And a second displacer 10 reciprocating in the second cylinder 6. The first displacer 9 and the second displacer 10 are connected in the axial direction by a connecting member 11.

A fluid passage 12 extending in the axial direction is formed inside the first displacer 9, and a cold storage material 13 made of a copper mesh or the like is accommodated in the fluid passage 12.

Similarly, a fluid passage 14 extending in the axial direction is formed inside the second displacer 10, and a cold storage material 15 formed of spherical lead or the like is accommodated in the fluid passage 14.

Between the outer peripheral surface of the first displacer 9 and the inner peripheral surface of the first cylinder 5 and between the outer peripheral surface of the second displacer 10 and the second
A seal mechanism 1 is provided between the cylinder 6 and the inner peripheral surface.
6,17 are glued.

The upper end of the first displacer 9 is connected to the reciprocating drive shaft 18, and the outer peripheral surface of the reciprocating drive shaft 18 is connected to the drive casing.
The seal mechanism 27 is mounted between the seal mechanism 27 and.

The upper part of the reciprocating drive shaft 18 has a U-shaped slider part.
The bearing 21 is attached to the eccentric cam 22 in the slider portion 19.

In front of the eccentric cam 22, another auxiliary cam for intake and exhaust operation
The eccentric cam 23 is provided on the shaft of the motor 24.

A spur valve 25 is provided on the side wall of the drive unit casing 42 in conjunction with the above-described eccentric cam 23 for intake and exhaust operations.
The refrigerant gas forms a circulation system between the inside and the compressor 30, that is, a high-pressure gas compressed by the movement of the spur valve 25 is introduced into the cylinder 3 through the passage of the spur valve 25, and vice versa. The gas becomes low-pressure gas via the drive section space 41 and returns to the compressor 30.

That is, the opening and closing of the spur valve 25 is controlled in a relationship described later in relation to the reciprocation of the displacer 4.

Next, the operation of the refrigerator configured as described above will be briefly described. In this refrigerator, the part where cold occurs, that is, the part supplied to the cooling surface, is connected to the first stage 7 and the second stage.
Stage 8. These cool to about 30K and 8K, respectively, when there is no heat load. For this reason, the temperature between the upper and lower ends of the first displacer 9 in the drawing is set to 30 ° C from normal temperature (300K).
A temperature gradient is formed up to K, and a temperature gradient from 30K to 8K is formed between the upper and lower ends of the second displacer 10 in the drawing.

However, this temperature varies depending on the heat load of each stage,
Usually, in the first stage 7, it is between 30 and 80K, and in the second stage 8 it is between 8 and 20K.

The eccentric cam 22 attached to the shaft of the motor 24 eccentrically moves the inner surface of the U-shaped slider portion 19 with the bearing 21 around the motor shaft, thereby reciprocating the drive shaft 18.
Moves up and down, and eventually, the displacer 4 connected to the reciprocating drive shaft 18 reciprocates in the cylinder 3.

Spur valve when displacer 4 is at top dead center
High pressure helium gas flows into the cylinder 3 at the intake side 25. Next, the displacer 4 moves to the bottom dead center. As described above, the outer peripheral surface of the first displacer 9 is
Between the inner peripheral surface of the cylinder 5 and the second displacer 10
Sealing mechanisms 16 and 17 are mounted between the outer peripheral surface of the second cylinder 6 and the inner peripheral surface of the second cylinder 6, respectively. Therefore, when the displacer 4 moves to the bottom dead center, the high-pressure helium gas passes through the fluid passage 12 formed inside the first displacer 9 and the fluid passage 14 formed inside the second displacer 10. It flows into a one-stage expansion chamber 35 formed between the first displacer 9 and the second displacer 10 and into a two-stage expansion chamber 36 formed between the second displacer 10 and the tip wall of the second cylinder 6. . With this flow, the high-pressure helium gas is cooled by the regenerators 13 and 14, and eventually the high-pressure helium gas flowing into the first-stage expansion chamber 35 is
The high-pressure helium gas flowing into the two-stage expansion chamber 36 is cooled to about 30K and about 8K.

Here, the spur valve 25 is on the exhaust side in conjunction with the eccentric cam 23 for intake / exhaust operation, and is a one-stage expansion chamber 35 and a two-stage expansion chamber.
The high-pressure helium gas in 36 expands and generates cold. The first stage 7 and the second stage 8 are cooled by this cold. Then, the displacer 4 moves to the top dead center again, and the helium gas in the first-stage expansion chamber 35 and the second-stage expansion chamber 36 is removed accordingly. The expanded helium gas is heated by the cold storage materials 13 and 15 and discharged through the fluid passages 12 and 14 and the drive space 41. Then, by repeating such an operation, freezing is continuously performed.

This type of refrigerator cools the superconducting magnet,
It can be used as a cooling source for an infrared sensor or as a cooling source for a cryopump, and is considered to be promising.

(Problem to be Solved by the Invention) The refrigerator configured as described above has the following problems. That is, (1) Since the spur valve is constituted by a structure using an eccentric cam and a spring, the movement of the displacer is indirect and lacks reliability.

(2) Further, since the spur valve is a vertically moving seal, there is a possibility that the sealing performance is uneasy and the performance is reduced.

(3) Further, the proportion of the spur valve as a drive unit is large and the whole is large, so that maintenance and inspection are not easy.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem, and has a suction and exhaust valve that swings in direct association with the reciprocating motion of a piston, thereby improving performance and reliability and simplifying a driving unit. It is another object of the present invention to provide a refrigerator capable of realizing miniaturization.

[Configuration of the invention]

(Means for Solving the Problems) In a first refrigerator of the present invention, a cylinder, a displacer capable of reciprocating in a predetermined direction in the cylinder, a drive shaft having one end attached to the displacer, A regenerator provided in the displacer, a conversion mechanism for converting a rotational driving force from a driving unit into a reciprocating motion and transmitting the reciprocating motion to the driving shaft, and mounted near the other end of the driving shaft; At a desired timing with respect to the movement of the drive shaft,
Suction / exhaust means for communicating between the inside and the outside of the cylinder and sucking / exhausting gas between the inside and the outside of the cylinder.

Further, in the second refrigerator of the present invention, a cylinder, a displacer capable of reciprocating in the cylinder in a predetermined direction, a drive shaft attached to the displacer, and a regenerator provided in the displacer. A conversion mechanism that converts the rotational driving force from the driving means into reciprocating motion and transmits the reciprocating motion to the driving shaft, and a seal body rotatably provided around the driving shaft, at a desired timing with respect to the motion of the driving shaft, Communicating the inside and outside of the cylinder,
Suction and exhaust means for sucking and discharging gas between the inside and outside of the cylinder.

Further, the suction / exhaust means is provided so as to be rotatable around the drive shaft, guide means protruding from the drive shaft, and provided on the seal body so as to engage with the guide means, A cam means formed to rotate the seal at a desired timing by the reciprocating motion of the seal, and communicating with one of a gas inlet and a gas outlet when the seal rotates at the desired timing. And gas is introduced or discharged into the cylinder through the communication means.

(Operation) According to the configuration described above, since the intake / exhaust valve is provided at the tip of the drive shaft directly connected to the displacer, the drive becomes direct and the reliability is improved.

Further, since the intake / exhaust valve is a swinging seal, the sealing performance is improved, and the performance is improved.

In addition, it can be provided on the drive shaft core, and eccentric cams and the like are not required, so that simplification and downsizing can be achieved.

Further, since no pressure difference is generated between the drive unit side and the displacer side, the motor capacity can be reduced, and the drive unit can be discharged to the atmosphere, so that the size and size can be greatly reduced and simplified.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

Note that the same members as those of the conventional device shown in FIG.
Duplicate description will be omitted.

FIG. 1 shows a refrigerator according to one embodiment of the present invention.

The refrigerator according to this embodiment differs from the conventional refrigerator in that a new intake / exhaust valve 50 is provided at the tip of the reciprocating drive shaft 18 instead of the spur valve 25. This reciprocating drive shaft
At the center of 18, a passage 51 communicating with the first and second cylinders 5, 6 is provided.

 Next, details of the intake and exhaust valve section 50 are shown in FIG.

A guide pin 52 is fixed to the end of the reciprocating drive shaft 18, and a seal body 53 is provided so as to surround the guide pin 52.

In the inside of the seal body 53, a cam groove 54 (third side) is taken into consideration so as to swing at an appropriate timing by the guide pin 52.
The development of the cam groove 54 is shown in FIG. ) Is provided inside the seal body 53, whereby the entire seal body 53 swings together with the reciprocating motion of the drive shaft 18. One groove 60 is provided outside the seal body 53, and the gas introduction passage 56, the gas discharge passage 57, and the groove 6 provided on the lid 55 side in accordance with the swing.
0 matches and communicates. In addition, the seal body 53 seals between the gas introduction passage 56 and the gas discharge passage 57 while swinging.

That is, the drive shaft is moved up and down by the reciprocating drive shaft 18.
The seal body 53 provided at the tip of 18 is provided with a guide pin 52 and a cam groove 54.
Swinging at an appropriate timing, whereby one groove 60 provided on the outside of the seal body 53 communicates with the gas conducting / discharging passages 57 and 56 provided on the lid 55 side at an appropriate timing.
Further, the inside of the first and second cylinders 5 and 6 communicates through the passage 51 at the center of the drive shaft 18, so that a gas passage is secured, and an appropriate cycle can be repeated.

As a result, the sealing performance is improved since the conventional sealing method using the spur valve 25 is replaced with the swinging sealing method of the sealing body 53.

The spur valve 25 has an eccentric cam 23 for intake and exhaust operation.
However, in this embodiment, the structure is directly connected as described above, and the reliability is increased.

In addition, the pressure between the upper and lower portions of the drive shaft 18 is conventionally the pressure in the cylinder fluctuating, whereas the upper end of the drive shaft 18 is constant at a low pressure. Although a pressure difference has occurred, in the above embodiment, since the intake and exhaust valve 50 is provided at the upper end of the drive shaft 18, the pressure between the upper and lower sides of the drive shaft 18 changes in the same manner, so that a differential pressure is not generated, The motor capacity can be reduced. In addition, the conventional drive unit is a gas passage space and is entirely sealed by the casing 42. However, in the present embodiment, only the distal end needs to be sealed, and the other parts are arranged in the atmosphere. . This operation and effect are obtained by providing the intake / exhaust means at the upper end of the drive shaft 18 without being limited to the type, system, etc. of the intake / exhaust valve.

Therefore, the entire drive unit can be significantly reduced in size and simplified.

It should be noted that the sealing performance can be improved even if the oscillating seal type intake / exhaust valve 50 is not provided at the upper end of the drive shaft 18 but is provided in the middle of the drive shaft 18 or the like.

As described above, according to the present invention, (1) the vertical movement seal system is changed from the vertical movement seal system to the swing seal system, whereby the sealing performance can be improved, and the performance can be improved.

(2) In addition, the structure is directly connected to the reciprocating motion from the indirect structure, so that reliability is improved and reliability is improved.

(3) Further, since the intake / exhaust valve 50 is provided at the upper end of the drive shaft 18, there is no differential pressure between the upper and lower portions of the drive shaft, so that the motor capacity can be reduced and the sealed portion can be limited. Possible, the drive unit and the whole are greatly reduced in size,
Simplification, maintenance and inspection are easy, and a refrigerator with greatly improved economic efficiency can be realized.

The present invention is not limited to the above embodiment, but can be variously modified and used without departing from the scope of the invention.

〔The invention's effect〕

As described in detail above, according to the present invention, a refrigerator having improved sealing performance reliability, a reduced driving force capacity, and a small overall size is realized.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a refrigerator according to one embodiment of the present invention,
FIG. 2 is a schematic diagram showing intake and exhaust means of the refrigerator of the present invention,
FIG. 3 is a development view of a cam groove in the intake / exhaust means of the refrigerator of the present invention, FIG. 4 is a schematic sectional view showing a passage section of the intake / exhaust means, and FIG. 5 is a schematic view showing a conventional refrigerator. FIG. 1 ... cold head, 2 ... refrigerant gas guide and discharge system, 3 ...
... Cylinder, 4 ... Displacer, 5 ... First cylinder, 6 ... Second cylinder, 7 ... First stage, 8 ...
2nd stage, 9 ... 1st displacer, 10 ... 2nd
Displacer, 11… Connecting bracket, 13,15 …… Cooling material, 1
6, 17, 27: Seal member, 18: Reciprocating drive shaft, 19: Slider part (reciprocating part), 21: Bearing, 22 ...
Eccentric cam (conversion mechanism), 24 motor (drive means) 50 intake / exhaust valve (intake / exhaust means) 52 guide pin (guide means) (intake / exhaust means) 53 seal body (intake / exhaust means) 54 ... Cam groove (cam means), 56 ... Gas introduction passage, 57 ...
... gas discharge passage, 60 ... groove (communication means).

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁶ , DB name) F25B 9/14 530

Claims (3)

(57) [Claims] 1. A cylinder, a displacer reciprocally movable in a predetermined direction in the cylinder, a drive shaft having one end attached to the displacer, a regenerator provided in the displacer, and a vicinity of the other end of the drive shaft. The seal body, which is attached to the drive shaft and is rotatably provided around the drive shaft, is directly linked to the reciprocating motion of the drive shaft and rotates at a desired timing, thereby connecting the inside and the outside of the cylinder. A suction / exhaust means for communicating and sucking / exhausting gas between the inside and the outside of the cylinder; a drive means for driving the seal body via the drive shaft; and a reciprocating rotational drive force from the drive means. And a conversion mechanism for converting the transmission into the drive shaft and transmitting the transmission to the drive shaft. 2. A cylinder, a displacer capable of reciprocating in the cylinder in a predetermined direction, a drive shaft attached to the displacer, a regenerator provided in the displacer, and rotatable around the drive shaft. The seal body provided is
By directly interlocking with the reciprocating motion of the drive shaft and rotating at a desired timing, the inside and outside of the cylinder communicate with each other, and the suction and exhaust of gas between the inside and outside of the cylinder are performed. Exhaust means; drive means for driving the seal body via the drive shaft; and a conversion mechanism for converting rotational driving force from the drive means into reciprocating motion and transmitting the reciprocating motion to the drive shaft. Characterized refrigerator. 3. The intake / exhaust means is provided so as to be rotatable around the drive shaft, guide means protruding from the drive shaft, and provided on the seal body so as to engage with the guide means. A cam means formed in a shape in which the seal body rotates at a desired timing by the reciprocating motion of the guide means, and when the seal body rotates at the desired timing,
3. A communication means communicating with either one of a gas inlet and a gas outlet, and wherein the gas is introduced or discharged into the cylinder through the communication means. refrigerator.