JPH0771834A - Cryogenic refrigerator - Google Patents

Abstract

PURPOSE:To reduce vibration and noise of a motor by disposing an elastic member between a flange formed on a bulged portion on the side surface of a crosshead and an annular groove-shaped surface of a locking hole formed by a displacer and an end cap to prevent the flange and the annular groove- shaped surface from contacting each other. CONSTITUTION:A locking hole facing a recess 2 is formed by the recess 2 formed on one end surface of a displacer 106 for receiving cold storage material and an end cap 3 which is mounted to the end surface and whose middle portion is opened. And a bulged portion on the side of a crosshead 6 attached to an end of a Scotch yoke 1 is loosely fitted into the locking hole. In this case, the locking hole is formed in an annular groove 4 in communication therewith and the bulged portion on the side of the crosshead 6 is formed in a continuous flange 7. And a continuous or intermittent protrusion 71 is formed on the outer periphery of the flange 7. Further an elastic member, e.g. O-ring 8, is fitted on either side of the protrusion 71 to prevent the flange 7 and the annular groove 4 from contacting each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cryogenic refrigerator for cryogenic refrigeration by a Gifode-McMahon cycle, a Stirling cycle and the like.

[0002]

2. Description of the Related Art As a cryogenic refrigerator of this type, one having a structure as shown in FIG. 4 is well known. In the cryogenic refrigerator of FIG. 4, the electric motor 102 drives the crank mechanism 103, and the crank mechanism 103 includes the air supply valve 104 and the exhaust valve 111.
And the reciprocating operation of the Scotch yoke 1 are reciprocally driven with a required stroke phase difference.

A first displacer 106 and a second displacer 108 are connected to the scotch yoke 1, and the first displacer 106 and the second displacer 1 are connected to each other.
08 reciprocates in the first cylinder 105 and the second cylinder 107 with the same stroke phase.

The first displacer 106 and the second displacer 108 perform an expansion cooling process near the end point of the stroke moving to the lower side of the figure, and perform an exhaust stroke in the stroke moving to the upper side of the figure, and from the near end point thereof. Perform an intake stroke.

In the intake stroke, the pressurized refrigerant 101 such as helium compressed by the refrigerant compression section (not shown) is supplied to the intake valve 10.
4, into the first cylinder 105, and from the ventilation hole 201 of the first displacer 106 to the ventilation hole 203 through the regenerator material 202 made of a copper net, a breathable sintered metal material or the like.
And enters the first expansion chamber 205 side. First expansion chamber 205
In the expansion cooling process, the pressurized refrigerant flows in the opposite direction to the flow of the refrigerant in the intake compression process, is discharged through the exhaust valve 111, and at the same time, expands to accumulate cold heat in the cold storage material 202.

During the same process as the first expansion cooling process, the refrigerant in the first expansion chamber 205 enters the second expansion chamber 209 from the ventilation hole 206 of the second displacer 108 through the regenerator material 207 such as granular lead. Enter, then flow in reverse and exhaust valve 11
At the same time as being discharged from No. 1, it expands and second expansion cooling is performed, and cold heat is stored in the regenerator material 207.

In the exhaust stroke, the second expansion chamber 209 and the first expansion chamber 209
The refrigerant that has finished the expansion cooling in the expansion chamber 205 and has been reduced in pressure passes through the second displacer 108 and the first displacer 106 via the route opposite to that in the expansion cooling operation described above.
The exhaust valve 111 passes through the inside of the crank mechanism 103, is discharged as the step-down refrigerant 112, returns to the refrigerant compression section (not shown), and is compressed again to become the pressurized refrigerant 101. This operation is repeated. To do.

Below, at the stroke positions of the first cylinder 105 and the second cylinder 107, the position point corresponding to the end point of the upward stroke of the drawing and the starting point of the downward stroke of the drawing is the top dead center. That is, the end point of the stroke toward the lower side of the figure and the position point corresponding to the start point of the stroke toward the upper side of the figure are called the bottom dead center. The inner shielding cover 116 covers a space from the portion of the first stage 115 provided on the top dead center side of the first cylinder 105 to the entire second cylinder 107 to cool the cooling chamber 1.
The cooling target fluid 30 from the device serving as the cooling load 400 is formed from the opening end side of the cooling chamber 117.
Introduce 0.

A first heat-absorbing fin 120 having a shutter-like air passage is disposed on the opening end side of the cooling chamber 117, and a shutter is provided on the second stage 118 provided on the top dead center side of the second cylinder 107. The second heat-absorbing fins 119 having the air passages are arranged, and the cold heat generated in the first stage 115 and the second stage 118 is transferred to the respective surfaces of the first heat-absorbing fins 120 and the second heat-absorbing fins 120.
The required cooling is performed by supplying the cooling target fluid 300 via the respective surfaces of the heat absorbing fins 119.

The outer shield cover 113 has a first cylinder 105.
A vacuum chamber 114 is formed covering the outside from the bottom dead center side to the opening end side of the cooling chamber 117.
The outer surface of the first cylinder 105 and the outer surface of the cooling chamber 117 are shielded from the external environment to prevent heat loss of cold heat.

Then, the Scotch yoke 1 and the first displacer 106 face the first displacer 106 and the center as shown in FIG. 5, that is, when facing the recess 2 formed on one end surface of the first displacer 106. In the locking hole 4A formed with the end cap 3 whose part is open,
In many cases, the scotch yoke 1 is attached to one end of the scotch yoke 1 and the side bulging portion 7A of the cross head 6 made of steel or the like fixed by the pin 5 is loosely fitted to be connected.

The thickness of the side bulging portion 7A and the locking hole 4A
Is usually formed with a clearance of about 0.1 to 0.2 mm so that the axial center of the first displacer 106 can be adjusted.

Scotch yoke 1 and first displacer 1
In the cryogenic refrigerator having the above-described configuration that does not include a cushioning material between the first displacer 106 and the second displacer 108, the scotch yoke 1 causes the first displacer 106 and the second displacer 108 to reciprocate in each cylinder. (1) Vibration of the electric motor is transmitted to the displacer without being attenuated. (2) Vibration caused by sliding of the displacer is also difficult to attenuate. (3) Whenever the direction of movement of the displacer changes, the crosshead hits the displacer side or the end cap side by the amount of the clearance provided for adjusting the axial center, which causes vibration and noise due to impact.

There is a problem called ".

[0015]

Therefore, there is a problem that it is difficult to use as a refrigerator mounted in a semiconductor manufacturing apparatus for manufacturing a VLSI or the like which must realize a submicron line width. Further, since the above-mentioned vibration impairs the sealability of the piston ring of the second displacer, there is also a problem that the cooling temperature fluctuates, and there has been a problem to solve these problems.

[0016]

SUMMARY OF THE INVENTION According to the present invention, a concave portion formed on one end surface of a displacer accommodating the above-described cold storage material and an end having a central portion attached to the one end surface of the displacer is open. A cap is formed with a locking hole facing the recessed portion, and a side bulge portion of the crosshead attached to one end of the scotch yoke is loosely fitted in the locking hole, and the rotation operation of the electric motor is performed through the scotch yoke. In a cryogenic refrigerator that obtains a driving force for reciprocating the displacer in the cylinder,

The engaging hole is formed in a continuous annular groove, the side surface bulging portion of the crosshead is formed in a continuous flange, and a continuous annular convex portion is formed on the outer peripheral surface of the flange. A first device having a structure in which elastic members that prevent contact between the flange and the annular groove forming surface are mounted on both sides of the annular convex portion;

The side surface bulging portion of the crosshead is formed on a continuous flange, and a continuous annular recess is formed on each surface of at least one of the annular groove and the flange. By providing a second device having a configuration in which an elastic member that blocks contact between the flange and the annular groove forming surface is provided in the recess, the above-mentioned problems of the conventional technology are solved.

[0019]

Since the scotch yoke and the displacer are in contact with each other through the elastic member, the vibration of the electric motor is absorbed by the elastic member, the vibration transmitted to the displacer is reduced, and the noise is also reduced.

[0020]

【Example】

(Embodiment 1) A first embodiment of the present invention will be described below with reference to FIG. In addition, in FIG. 1, the portions denoted by the same reference numerals as those in FIGS. 4 and 5 are the portions having the same functions as the portions described with reference to these drawings, and the description thereof is omitted within the range that does not hinder the understanding of the present invention.

Reference numeral 4 in the drawing denotes a continuous annular groove formed by the first displacer 106 and the end cap 3 so as to face the concave portion 2. And 7 is this annular groove 4
It is a flange of the crosshead 6 formed to have a thickness that allows loose fitting, and a continuous annular convex portion 71 is formed on the outer peripheral surface of the flange 7.

On both sides of the annular convex portion 71, elastomer O-rings 8 made of elastic material such as Teflon are attached. The O-ring 8 has a thickness that can prevent contact between the respective wall surfaces forming the annular groove 4 and the crosshead 6, for example, the thickness of the parallel portion of the flange 7 is t1, and the thickness of the parallel portion of the annular convex portion 71 is t1. T2, annular groove 4
Where W is the width and φ is the diameter before the O-ring 8 is mounted, for example, W-t1 = 0.2 to 0.3 (mm) 2φ + t2-W = 0.2 to 0.5 (mm) is satisfied. The thickness is set to the extent that

Since the scotch yoke 1 and the first displacer 106 are connected via the elastomer O-ring 8 in the cryogenic refrigerating apparatus of the present invention having the above-described structure, the rotational driving force of the electric motor 102 is increased. When changing to a linear reciprocating movement via the Scotch yoke 1, the electric motor 102
Of the first displacer 106 and the second displacer 1 are difficult to be transmitted to the first displacer 106 side.
The vibration caused by the sliding of 08 is also easily attenuated.
Further, since the clearance between the annular groove 4 and the flange 7 of the crosshead 6 is filled with the elastomer O-ring 8, collision with the first displacer 106 of the crosshead 6 and the end cap 3 is avoided,
As a result, vibration and noise due to impact have been eliminated.

Although the two thick O-rings 8 avoid contact between the crosshead 6 and the first displacer 106 or the end cap 3, the O-ring 8 is made of an elastomer, and the contact amount is, for example, about 8%. It can be compressed and its axis can be adjusted.

(Second Embodiment) A second embodiment of the present invention will be described below with reference to FIG. In addition, in FIG.
Portions indicated by the same reference numerals as those in FIG. 4 and FIG. 5 have the same functions as the portions described with reference to these drawings, and in this case as well, description thereof is omitted within the range that does not hinder the understanding of the present invention.

In the figure, 9A, 9B and 9C are annular recesses formed on the respective surfaces of the first displacer 106 and the end cap 3 which face the annular groove 4, and are made of an elastomer having a diameter larger than the depth of the annular recess. An O-ring 8 is attached to each wall surface forming the cross head 6 and the annular groove 4, that is, the first displacer 10 by the O-ring 8.
6 and the end cap 3 are prevented from contacting each other.

Therefore, also in the case of the second embodiment, it is possible to obtain the same operational effect of reducing the vibration and noise as in the case of the first embodiment.

The present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the claims. For example, the material of the O-ring 8 that prevents contact between the surface forming the annular groove 4 and the flange 7 may be any material having elasticity and a vibration damping effect. Used by choice.

Further, the annular convex portion 71 can be replaced by a convex strip or the like formed intermittently within a range that does not hinder the positioning of the O-ring 8, and the annular groove 4 ends the circumferential step. It is also possible to provide it on the side of the cap 3 or to form part or all of the annular recesses 9A, 9B, 9C on the side of the flange 7 of the crosshead 6. When the annular recesses 9A, 9B, 9C are formed on the flange 7 side, the members to be handled are light and small, and
Since the annular concave portion is formed on the outer surface side, there is an advantage that the work becomes easy.

Further, it is also possible to carry out as shown in FIG.

[0031]

As described above, according to the present invention, although the structure is simple, it is possible to greatly reduce the transmission of vibrations from the electric motor to the displacer, and to prevent the displacer from sliding in the cylinder. The effect of damping the accompanying vibrations is great. It is also possible to absorb most of the impact force when reversing the moving direction of the displacer, and 0.2 m because an elastic member is attached.
If it is about m, the elastic member can be deformed to adjust the axial center. Further, since the vibration is reduced, the sealability of the piston ring of the second displacer is improved, so that the temperature characteristics are stabilized and the reliability is improved.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a first embodiment.

FIG. 2 is an explanatory diagram showing a second embodiment.

FIG. 3 is an explanatory view showing another embodiment.

FIG. 4 is an explanatory diagram of a conventional technique.

FIG. 5 is an explanatory diagram of a main part of a conventional technique.

[Explanation of symbols]

 1 Scotch Yoke 2 Recessed part 3 End cap 4 Annular groove 4A Locking hole 5 Pin 6 Crosshead 7 Flange 7A Side bulge 8 O-ring 9A, 9B, 9C Annular recess 71 Annular projection 102 Electric motor 106 First displacer

Claims (2)

[Claims] 1. A locking hole facing a concave portion formed by a concave portion formed on one end surface of a displacer accommodating a cool storage material and an end cap having a central portion attached to the one end surface of the displacer. A driving force for reciprocally moving the displacer in the cylinder from the rotational movement of the electric motor by loosely fitting the side surface bulging portion of the crosshead attached to one end of the scotch yoke in the locking hole. In the cryogenic refrigerator for obtaining the above, the locking hole is formed in a continuous annular groove, and the side surface bulging portion of the crosshead is formed in a continuous flange, and is continuously or intermittently formed on the outer peripheral surface of the flange. A cryogenic refrigerator characterized in that a convex portion is formed, and elastic members for preventing contact between the flange and the annular groove forming surface are mounted on both sides of the convex portion. 2. A locking hole facing the recessed portion is formed by a recessed portion formed on one end surface of the displacer accommodating the cold storage material and an end cap having a central portion that is attached to the one end surface of the displacer. A driving force for reciprocally moving the displacer in the cylinder from the rotational movement of the electric motor by loosely fitting the side surface bulging portion of the crosshead attached to one end of the scotch yoke in the locking hole. In the cryogenic refrigerator to obtain, while forming the locking hole in a continuous annular groove, the side surface bulging portion of the crosshead is formed in a continuous flange, and at least one of the annular groove and the flange A continuous annular recess is formed on each of the surfaces on one side, and an elastic member that prevents contact between the flange and the annular groove forming surface is attached to each of the annular recesses. A characteristic cryogenic refrigerator.