JPH06300378A - Varying mechanism for valve timing of very low temperature refrigerator - Google Patents

Abstract

PURPOSE:To obtain a mechanism for making variable the valve timing of a very low temperature refrigerator, which can vary the valve timing of the very low temperature refrigerator from outside the machine. CONSTITUTION:Attention being paid to that valve timing can be made variable by making changeable the relative position of a valve disc 42 to a valve plate 29, a rotary valve is constructed of the valve plate 29 and the valve disc 42 and also a valve disc rotating mechanism 41 having a crank pin 43 and a circular handle 44 and making the valve disc 42 rotatable in relation to the valve plate 29 is provided from outside a very low temperature refrigerator 40.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable valve timing mechanism for a cryogenic refrigerator.
McMahon refrigeration cycle refrigerator (hereinafter "GM refrigerator")
(Referred to as “”) and the like, which is capable of optimizing the timing (valve timing) of intake and exhaust of a working fluid (refrigerant gas such as helium gas) in a cryogenic refrigerator.

[0002]

2. Description of the Related Art A conventional GM refrigerator will be described with reference to FIGS. FIG. 4 is a vertical cross-sectional view of the GM refrigerator 1. The GM refrigerator 1 is a refrigerator including a Gifford-McMahon refrigeration cycle in which a compressor 2 and a refrigerator 3 are connected.

The compressor 2 sucks a refrigerant gas (helium gas) from its low pressure side 2A, raises the pressure of the refrigerant gas, cools it, discharges it to the high pressure side 2B, and supplies it to the refrigerator 3. Cooling of the refrigerant gas is performed by water cooling or air cooling, but illustration is omitted here.

The refrigerator 3 is divided into a housing portion (housing 4) and a cylinder portion (cylinder 5).
That is, the refrigerator 3 includes a housing 4 and a cylinder 5.
A motor 6, a crank member 7, a scotch yoke 8 and a rotary valve 9 provided in the housing 4, a displacer 10 provided in the cylinder 5, and a first cooling stage 11 provided on the outer wall of the end of the cylinder 5. And a second cooling stage 12.

The housing 4 has a high pressure side 2B of the compressor 2.
And a refrigerant gas outlet port 14 that recirculates to the low-pressure side 2A of the compressor 2 is formed.

A two-stage displacer 10 is housed in the cylinder 5 so as to be slidable up and down, and the sliding portion is sealed.

A first regenerator material 15 and a second regenerator material 16 are built in the displacer 10, and a first space 17 (room temperature space) and a second space 18 are provided between the displacer 10 and the cylinder 5.
The (first expansion space) and the third space 19 (second expansion space) are formed, and the displacer 10 has a first communication hole 20, a second communication hole 21, and a third communication hole 22.
Further, the fourth communication hole 23 is formed so that they can communicate with each other.

With the reciprocating movement of the displacer 10, the volumes of the second space 18 and the third space 19 change in proportion to each other, and at the same time, the second space 18 and the third space 19 and the first space. 17 and the volume change in inverse proportion to each other.

The first cooling stage 11 and the second cooling stage 12 are formed of flanges, and they are provided in close contact with the outer wall of the displacer 10 so as to be able to conduct heat.

The first cooling stage 11 and the second cooling stage
A cryopump (not shown) is attached to the cooling stage 12 to condense (cool and solidify) various gas molecules such as nitrogen in a closed space, and simultaneously adsorb directly or indirectly by activated carbon. It can be used as a kind of vacuum pump.

FIG. 5 shows a crank member 7 in the housing 4,
FIG. 6 is an exploded perspective view of the Scotch yoke 8 and the rotary valve 9, and FIG. 6 is an exploded perspective view of the rotary valve 9. The motor 6 has a drive rotary shaft 24, and the crank member 7 is a crank pin protruding on its circumference. 25, the Scotch yoke 8 has a horizontally long flat plate 26, a vertical shaft 27, and a roller bearing 28. The rotary valve 9 has a valve plate 29, a valve body 30, and a compression spring 31.
And a fixing pin 32.

The driving rotary shaft 24 of the motor 6 penetrates through the center of the cylindrical crank member 7 and is fixed by a key (not shown).

The pins 25 of the crank member 7 are fitted into the roller bearings 28 of the scotch yoke 8 and the crank pin engaging holes 33 formed in the valve plate 29, respectively, to give a rotary motion.

The lower part of the vertical shaft 27 of the scotch yoke 8 is fixed to the upper part of the displacer 10, and a horizontally long window 34 is formed in the horizontally long flat plate 26 to provide a roller bearing 28.

The roller bearing 28 is an inner diameter bearing which has an outer shape that is rotatably movable in the horizontally long window 34 and which fits into the crank pin 25 of the crank member 7.

The scotch yoke 8 regulates its rotational movement in the horizontal plane by a pin (not shown) for preventing rotation of the horizontally long flat plate 26, and a pair of sliding bearings 35 (FIG. 4) also serving as a seal member vertically move the scotch yoke 8 up and down. The shaft 27 is received so that it can move up and down in the housing 4.

That is, the scotch yoke 8 converts the rotational movement of the crank member 7 into the vertical reciprocating movement of the displacer 10.

Valve plate 29 of rotary valve 9
5 has a cylindrical shape as shown in FIGS. 5 and 6, has a flange portion, is made of an aluminum alloy, and its surface is subjected to abrasion resistance treatment.

The valve plate 29 has a low pressure side surface 29A located on the crank member 7 side, and a low pressure side surface 29A and a high pressure side surface 29B are provided on a high pressure side surface 29B facing the valve body 30 on the side opposite to the low pressure side surface 29A. A circular arc-shaped through hole 29C that communicates with each other is opened, and a radial long groove 29D is formed on the surface of the high-pressure side surface 29B.

The valve body 30 of the rotary valve 9 is
A first side surface 30A that is in a cylindrical shape using a polymer material such as Teflon and that is in close contact with the high-pressure side surface 29B, and a first side surface 30A.
Of the compressor 2 on the high pressure side 2B opposite to the side surface 30A
And a second side surface 30B that receives the high-pressure gas from the side, and a center through hole 30C that connects the first side surface 30A and the second side surface 30B is formed.

Further, the arcuate groove 3 is formed on the first side surface 30A.
0D, a communication rectangular hole 30E communicating with the arcuate groove 30D and opening to the outer peripheral surface of the valve body 30, and a fixing hole 30F into which the fixing pin 32 is inserted.

In particular, as shown in FIG. 4, the communication rectangular hole 3
OE communicates with the first space 17 of the displacer 10 via the gas flow path 36 of the housing 4.

FIG. 7 shows the valve plate 29 and the valve body 3
0 contact surface (high-pressure side surface 29B and first side surface 30)
FIG. 13 is an explanatory view of (A) as viewed from the valve body 30 side, and as shown in the figure, the arc-shaped through hole 29C has a valve plate 29
A circular hole formed at a position having a radius equal to the distance between the center through hole 30C and the arcuate groove 30D from the center of the circle has a shape obtained by expanding a certain circumferential angle on the circumference of the same radius.

The radial elongated groove 29D having the oval shape of the valve plate 29 has a length equal to the distance between the center through hole 30C and the arcuate groove 30D from the center of the valve plate 29.

The shape of the arcuate groove 30D of the valve body 30 is similar to that of the arcuate through hole 29C.
It is expanded by a certain circumferential angle to a position having a radius equal to the distance between the center through hole 30C and the arcuate groove 30D from the center of.

Therefore, the valve plate 29 and the valve body 30 have their central axes aligned with each other, and the valve plate 29 slides and rotates while the high-pressure side surface 29B and the first side surface 30A thereof are in close contact with each other. so,
The center through hole 30C and the radial direction long groove 29D are always in communication with each other, and when the radial direction long groove 29D communicates with the arcuate groove 30D as the valve plate 29 rotates, the intake valve "opens" and When the exhaust valve is "closed" and the arcuate through hole 29C communicates with the arcuate groove 30D, the intake valve is "closed" and the exhaust valve is "open".

The valve plate 29 has a bearing 37.
As shown in FIG. 4, it is rotatable and is fixed to the housing 4 so as not to move in the axial direction.

The valve body 30 is fixed to the housing 4 by a fixing pin 32 so that it cannot rotate, but it is slidable in the axial direction.
The sliding parts are sealed.

The compression spring 31 engages with the second side surface 30B of the valve body 30 to generate an extension force, but is for preventing the valve body 30 from being biased in the event of an erroneous operation. Even if there is no 31, it is not related to cooling and temperature rise.

The normal cooling mode operation of the GM refrigerator 1 having such a configuration will be described. The high-pressure helium gas discharged from the compressor 2 is guided into the housing 4 from the refrigerant gas inlet 13 by the flow path, and a part of the helium gas is compressed by the compression spring 31.
At the same time, the valve body 30 is pressed against the valve plate 29.

Most helium gas is used in the valve body 3
0 through the center through hole 30C to the radial long groove 29D of the valve plate 29.

The valve plate 2 is rotated by the rotation of the motor 6.
When 9 rotates counterclockwise with respect to the high pressure side surface 29B in FIG. 6 and the radial long groove 29D and the arcuate groove 30D start to be connected, the so-called intake valve starts to open and the scotch yoke 8 and the displacer 10 move. It reaches the bottom dead center and begins to rise.

As the intake valve “opens” and the displacer 10 rises, the helium gas passes through the central through hole 3
0C, the radial direction long groove 29D, the arcuate groove 30D, the communication rectangular hole 30E, and the gas flow path 36 in this order, and is cooled from the first space 17 by the first regenerator material 15 and the second regenerator material 16, The second space 18 and the third space 19 are filled.

When the displacer 10 ascends as shown in FIG. 8 and reaches the top dead center, the radial elongated groove 29D and the arcuate groove 30D are disconnected, and the arcuate through hole 29C is replaced by a circle. The connection with the arcuate groove 30D begins.

Therefore, the high-pressure helium gas from the compressor 2 is closed in the direction of the cylinder 5, the so-called exhaust valve is opened, and the displacer 10 descends and the second space 18 and the third space 19 are closed. High-pressure helium gas expands and cools, and the first regenerator material 15 and the second regenerator material 2
While cooling the regenerator material 16, the gas flow path 36, the communication rectangular hole 30E, the arc-shaped groove 30D, and the arc-shaped through hole 29C.
Through the scotch yoke 8 and the vicinity of the crank member 7, and returns from the refrigerant gas outlet 14 to the compressor 2.

By repeating such a cycle, the intake valve is first opened by the rotation of the valve plate 29 and the displacer 10 is raised, whereby the helium gas is cooled by the first regenerator material 15 and the second regenerator material 16. To fill the second space 18 and the third space 19.

Next, the exhaust valve is opened, the helium gas in the second space 18 and the third space expands and cools, and the displacer 10 descends, so that the cooled helium gas causes the first regenerator material to cool. 15 and second regenerator material 16
Return to the compressor 2 while cooling.

The relationship between the valve timing of the refrigerating cycle and the displacer 10 is shown in FIG. 9 as a diagram.

FIG. 9 is a diagram schematically showing the open / closed state of the valve (valve timing) according to the crank angle.
Corresponding to the view of the valve body 30 from the valve plate 29 side, the top dead center of the circle in the figure corresponds to the top dead center of the displacer 10, and the exhaust valve “open” before the top dead center. The portion marked with is a state in which the arc-shaped through hole 29C and the arc-shaped groove 30D are connected, and the portion marked with the intake valve “open” before the bottom dead center is the radial long groove 29D and the arc-shaped groove 30D. Shows the state of being connected.

In FIG. 9, the intake valve opens at an angle θ1 before bottom dead center, the displacer 10 rises, and the helium gas is filled in the second space 18 and the third space 19, and the angle before top dead center is increased. At θ2, the intake valve closes.

Displacer 10 after some time
The exhaust valve opens at an angle θ3 before the top dead center, exhausts when the displacer 10 descends, and closes at an angle θ4 before the bottom dead center.

As described above, the valve timing of the conventional GM refrigerator 1 is fixed, and it is determined to be optimal for a certain design rotation speed of the refrigerator 3, and the operation of the GM refrigerator 1 is performed. There is a problem that the valve timing cannot be changed.

Recently, the refrigerator 3 in which the magnetic material is used as the second regenerator material 16 has started to be used, and the refrigerator 3 is often operated while changing its rotation speed.

However, such valve timing is
Theoretically, ideally, the intake valve should open and the exhaust valve should close at bottom dead center, and the intake valve should close and the exhaust valve should open at top dead center. In consideration of this, there is a delay in intake and exhaust of helium gas in 9. Therefore, in consideration of this, the opening position of the intake valve is set to an angle θ1 before bottom dead center, and the closing position of the exhaust valve is set to an angle θ4 before bottom dead center. Set the opening position of the exhaust valve to the angle θ before top dead center.
3, and the closing position of the intake valve is set to the angle θ2 before the top dead center.

Since each of these angles is determined to be optimum for one certain rotation speed of the refrigerator 3,
When the number of rotations is changed, there is a problem that the angle is not optimal for the changed number of rotations.

Further, when regenerating the GM refrigerator 1, it is necessary to raise the temperature in the cylinder 5 of the refrigerator 3 to room temperature. However, in the method of raising the temperature by heating from the outside of the cylinder 5. take time.

As another method of raising the temperature, a method of reversing the motor 6 can be considered, but in this method, when the valve timing of the intake / exhaust valve is set to the cooling mode, the motor 6 is simply reversed to raise the temperature. Even in the temperature mode, there is a problem that the temperature does not rise above the predetermined temperature.

Further, in the case of performing such a temperature increase, it is possible to shift the valve timing by 180 degrees while the rotation of the motor 6 remains in the normal rotation of the cooling mode, but as described above, the conventional GM refrigeration is used. In Aircraft 1, it was impossible to change the valve timing during its operation.

[0049]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is possible to change the valve timing of a cryogenic refrigerator such as a GM refrigerator from the outside of the refrigerator. An object is to provide a variable valve timing mechanism for a low temperature refrigerator.

[0050]

That is, the present invention focuses on the fact that the valve timing can be changed by changing the relative position of the valve body of the rotary valve to the valve plate, and the working fluid is compressed. Compressor, a rotary valve that controls the flow path of the working fluid compressed by this compressor, a cylinder that contains this working fluid, a displacer that reciprocates in this cylinder, and a displacer that is housed in this displacer. A variable valve timing mechanism for a cryogenic refrigerator having a cold storage material, wherein the rotary valve comprises the valve plate and a valve body, and the valve body is provided from outside the cryogenic refrigerator. It is characterized in that a valve body rotation mechanism that enables rotation with respect to A variable valve timing mechanism of the cryogenic refrigerator.

An intake valve and an exhaust valve can be provided between the valve plate and the valve body, and the opening / closing timing of the intake valve and the exhaust valve can be adjusted by the valve body rotating mechanism.

The valve body rotating mechanism may include a crank pin that engages with the valve body and a handle that can rotate the crank pin.

A fixing pin that can fix the handle at a predetermined position can be provided.

An annular groove capable of communicating with the cylinder may be formed on the outer peripheral surface of the valve body.

A radial elongated groove and a circular arc-shaped through hole, and a central through hole and a circular arc-shaped groove are formed on respective surfaces of the valve plate and the valve main body which are in contact with each other, and these diameters are formed by the valve main body rotating mechanism. It is possible to adjust the timing at which the direction long groove and the arcuate through hole and the arcuate groove communicate with each other.

The radial elongated groove and the arc-shaped through hole are formed on the high pressure side surface of the valve plate, and the center through hole and the arc-shaped groove are formed on the first side surface of the valve body. Of the central through hole of the valve plate is communicated with the radial elongated groove of the valve plate, and the arcuate groove of the valve body is either the radial elongated groove of the valve plate or the arcuate through hole due to rotation of the valve plate. It is possible to open and close the intake and exhaust of the working fluid by allowing the crab to communicate.

The valve body rotating mechanism makes it possible to adjust the timing at which the arcuate groove of the valve body communicates with either the radial elongated groove of the valve plate or the arcuate through hole.

[0058]

In the variable valve timing mechanism of the cryogenic refrigerator according to the present invention, since the valve body of the rotary valve can be rotated from the outside of the refrigerator, the valve timing depending on the rotation speed of the refrigerator, that is, The opening and closing timings of the intake and exhaust valves can be changed arbitrarily to obtain optimum operating conditions, and even when the temperature is raised during regeneration of the refrigerator, the optimum valve timing in the temperature raising mode is obtained. be able to.

[0059]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a variable valve timing mechanism 41 of a cryogenic refrigerator 40 according to an embodiment of the present invention will be described with reference to the drawings. However, the same parts as those in FIGS. 4 to 9 are designated by the same reference numerals, and the detailed description thereof will be omitted.

FIG. 1 is a vertical sectional view of a variable valve timing mechanism 41 of the cryogenic refrigerator 40. The variable valve timing mechanism 41 is a valve body 4 corresponding to the valve body 30.
2, a crank pin 43, a circular handle 44, a fixing pin 45, a compression spring 46, and a bearing 47.
And a first seal 48, a second seal 49 and a third seal 50.

The housing 4 is formed with a high-pressure flow path 51 corresponding to the refrigerant gas inlet 13.

FIG. 2 is a perspective view of the valve body 42.
The valve body 42 has a cylindrical shape, and includes a first side surface 42A corresponding to the first side surface 30A that comes into close contact with the high-pressure side surface 29B, and
It has a second side surface 42B corresponding to the second side surface 30B opposite to the first side surface 42A.

A center through hole 42C corresponding to the center through hole 30C that connects the first side surface 42A and the second side surface 42B is formed in the valve body 42, and the arcuate groove 30D is formed in the first side surface 42A. And a communicating axial hole 42E corresponding to the communicating rectangular hole 30E communicating with the circular groove 42D, and the second side surface 42B corresponding to the fixing hole 30F. The fixing hole 42F is formed.

An annular groove 42G is formed on the outer peripheral surface of the valve body 42 so as to communicate with the communicating axial hole 42E and the gas flow passage 36 of the housing 4.

Therefore, even when the valve body 42 is at an arbitrary rotational position, the communicating axial hole 42E and the arcuate groove 42D are provided in the first space of the displacer 10 via the annular groove 42G and the gas flow passage 36. Communicate with 17.

It should be noted that one end of the crank pin 43 is inserted into the fixing hole 42F, the other end is supported by the bearing 47 to fix the circular handle 44, and the circular handle 44 is rotated to move the valve body 42 to the valve plate. It is rotatable with respect to 29.

A plurality of fixing pin holes 44A for inserting and fixing the fixing pins 45 are formed in the circular handle 44 at arbitrary intervals in the circumferential direction. That is, after adjusting the position of the valve body 42, the fixing pin 45 is inserted into the predetermined fixing pin hole 44A so that the valve body 42 does not rotate due to the rotation of the valve plate 29.

In the variable valve timing mechanism 41 having such a configuration, as in the case of the conventional GM refrigerator 1, the central axes of the valve plate 29 and the valve main body 42 are made to coincide with each other, and the high pressure side surface 29B and the first side surface 29B of the valve plate 29 are arranged. The side surfaces 42A of the valve plate 2 are in close contact with each other and are in contact with each other.
9, the center through hole 42C and the radial long groove 29D are always in communication with each other, and as the valve plate 29 rotates, the radial long groove 29D communicates with the arcuate groove 42D. The intake valve is “open” and the exhaust valve is “closed” when the arc-shaped through hole 29C is in the arc-shaped groove 42.
When communicating with D, the intake valve is "closed" and the exhaust valve is "open".

Further, by rotating the circular handle 44, the valve main body 42 is rotated from the outside to make the timing of intake and exhaust of the valve variable, and the optimum valve timing according to the number of rotations of the refrigerator 3 or the valve plate 29. Can be set to.

For example, when the rotation speed is slowed, the delay in intake and exhaust of helium gas is reduced, so that the intake valve open position and the exhaust valve close position are brought closer to the bottom dead center side, and the intake valve It is considered better to make the closing position and the exhaust valve opening position closer to the top dead center side.

In this case, the valve body 42 is rotated by, for example, the angle θ5 so that the timing of the rotary valve 9 is optimized, so that the intake valve opening position shown in FIG. θ5) and the closing position of the exhaust valve are the angle before the bottom dead center (θ4-θ5), and the closing position of the intake valve is the angle before the top dead center (θ2-
The angle θ5) and the position where the exhaust valve is closed can be set to an angle (θ3−θ5) before the top dead center.

However, since the arcuate through hole 29C, the radial groove 29D, the central through hole 42C and the arcuate groove 42D have constant lengths or sizes, the opening angle or time of the intake valve and the exhaust valve is constant. It doesn't change.

Further, the capacity of the refrigerator can be intentionally lowered by shifting the valve timing from the optimum position.

Further, by rotating the valve main body 42 by a large amount, for example, by 180 degrees, the intake / exhaust and the movement of the displacer 10 are in a temperature raising mode opposite to the above cooling mode, as shown in FIG. Also, it becomes possible to raise the temperature of the refrigerator, and it can be applied to increase the temperature of the refrigerator.

In the present invention, the valve body 42
Any mechanism can be adopted as a mechanism for rotating the valve, and a mechanism for manually or by a motor (not shown) can be adopted, and the angle of the valve body 42 may be controlled according to the rotation of the refrigerator.

Further, the mechanism for fixing the valve body 42 after rotating it is not limited to the fixing pin 45, and any other means can be adopted.

[0077]

As described above, according to the present invention, since the valve body is rotatable and the relative position with respect to the valve plate is variable, the valve timing for intake and exhaust can be set to any desired value. The valve timing can be adjusted from the outside of the refrigerator according to the number of rotations of the machine, and it can be applied to the temperature raising mode of the refrigerator.

[0078]

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a variable valve timing mechanism 41 of a cryogenic refrigerator 40 according to an embodiment of the present invention.

FIG. 2 is a perspective view of the valve body 42 of the same.

FIG. 3 is a diagram of a valve timing when the valve body 42 is rotated 180 degrees and the valve body 42 is viewed from the valve plate 29 side.

FIG. 4 is a vertical sectional view of a conventional GM refrigerator 1.

FIG. 5 is an exploded perspective view of a crank member 7, a scotch yoke 8 and a rotary valve 9 in the housing 4.

FIG. 6 is an exploded perspective view of a rotary valve 9 portion of the same.

FIG. 7 is a relative relationship diagram between the valve plate 29 and the valve body 30 of the same.

FIG. 8 is a vertical cross-sectional view of the GM refrigerator 1 at the top dead center of the displacer 10.

FIG. 9 is a diagrammatic view (corresponding to a view of the valve body 30 as viewed from the valve plate 29 side) schematically showing the open / closed state of the valve (valve timing) by the crank angle.

[Explanation of symbols]

1 GM refrigerator (Gifford McMahon refrigerator) 2 Compressor 2A Low pressure side of compressor 2 2B High pressure side of compressor 2 Refrigerator 4 Housing (housing part) 5 Cylinder (cylinder part) 6 Motor 7 Crank member 8 Scotch Yoke 9 Rotary valve 10 Displacer 11 First cooling stage 12 Second cooling stage 13 Refrigerant gas inlet 14 Refrigerant gas outlet 15 First regenerator material 16 Second regenerator material 17 First space (room temperature space) 18 2nd space (1st expansion space) 19 3rd space (2nd expansion space) 20 1st communicating hole 21 2nd communicating hole 22 3rd communicating hole 23 4th communicating hole 24 Drive Rotating shaft 25 Crank pin 26 Horizontal flat plate 27 Vertical shaft 28 Roller bearing 29 Valve plate 29A Low pressure side surface of valve plate 29 29 B high-pressure side surface of valve plate 29 29C arcuate through-hole of valve plate 29 29D radial slot of valve plate 29 30 valve body 30A first side surface of valve body 30 30B second side surface of valve body 30 30C of valve body 30 Center through hole 30D Arc-shaped groove of valve body 30E Rectangular hole for communication of valve body 30F Hole for fixing valve body 30 31 Compression spring 32 Fixing pin 33 Crank pin engaging hole 34 Horizontal window 35 Sliding bearing 36 Gas flow Road 37 Bearing 40 Cryogenic refrigerator 41 Varying valve timing mechanism of cryogenic refrigerator 42 Valve body 42A First side face of valve body 42B Second side face of valve body 42C Center through hole of valve body 42 42D Valve Arc-shaped groove 42E of main body 42 Valve main body 42 Axial hole for communicating with 42F Fixing hole of valve body 42 42G Annular groove of valve body 42 Crank pin 44 Circular handle 44A Fixing pin hole of circular handle 44 Fixing pin 46 Compression spring 47 Bearing 48 First seal 49 No. 2 seal 50 3rd seal 51 High pressure passage θ1 Angle before intake valve opening bottom dead center (before top dead center) θ2 Inlet valve closing angle before top dead center (before bottom dead center) θ3 Exhaust Angle of valve opening before top dead center (before bottom dead center) θ4 Angle of exhaust valve closing before bottom dead center (before top dead center) θ5 Timing of rotary valve 9 is optimal by rotating valve body 42 Angle to be

Claims (8)

[Claims] 1. A compressor for compressing a working fluid, a rotary valve for controlling a flow path of the working fluid compressed by the compressor, a cylinder containing the working fluid, and a displacer reciprocating in the cylinder. And a variable valve timing mechanism for a cryogenic refrigerator having a regenerator material housed in the displacer, wherein the rotary valve comprises the valve plate and a valve body, and A variable valve timing mechanism for a cryogenic refrigerator, comprising a valve body rotating mechanism that allows the valve body to rotate from the outside with respect to the valve plate. 2. An intake valve and an exhaust valve are provided between the valve plate and the valve body, and the opening / closing timing of the intake valve and the exhaust valve can be adjusted by the valve body rotating mechanism. A variable valve timing mechanism for a cryogenic refrigerator according to claim 1. 3. The valve for a cryogenic refrigerator according to claim 1, wherein the valve body rotating mechanism includes a crank pin that engages with the valve body, and a handle that can rotate the crank pin. Timing variable mechanism. 4. The valve timing variable mechanism for a cryogenic refrigerator according to claim 3, wherein a fixing pin capable of fixing the handle at a predetermined position is provided. 5. The variable valve timing mechanism for a cryogenic refrigerator according to claim 1, wherein an annular groove that can communicate with the cylinder is formed on an outer peripheral surface of the valve body. 6. A radial elongated groove and a circular arc-shaped through hole, and a central through hole and a circular arc-shaped groove are formed on respective surfaces of the valve plate and the valve main body that are in contact with each other, and the valve main body rotation mechanism is used to 2. The variable valve timing mechanism for a cryogenic refrigerator according to claim 1, wherein a timing at which the radial long groove and the arc-shaped through hole and the arc-shaped groove communicate with each other can be adjusted. 7. The radial elongated groove and the arc-shaped through hole are formed on a high pressure side surface of the valve plate, and the center through hole and the arc-shaped groove are formed on a first side surface of the valve body, The center through hole of the valve body is communicated with the radial elongated groove of the valve plate, and the arcuate groove of the valve body is rotated by the rotation of the valve plate so that the radial elongated groove of the valve plate or the arcuate through hole. 7. The variable valve timing mechanism for a cryogenic refrigerator according to claim 6, wherein the intake / exhaust of the working fluid is opened / closed by allowing communication with any of the above. 8. The valve body rotating mechanism is capable of adjusting a timing at which the arcuate groove of the valve body communicates with either the radial elongated groove of the valve plate or the arcuate through hole. The valve timing variable mechanism for a cryogenic refrigerator according to claim 7.