JP4197341B2 - Regenerator type refrigerator - Google Patents

Description

  The present invention relates to a regenerator refrigerator, and more particularly, to a regenerator refrigerator that uses a rotary valve to switch between supply of working fluid to a cylinder and discharge of working fluid from the cylinder.

  A Gifford McMahon (GM) refrigerator is known as a refrigerator that generates an extremely low temperature. The GM refrigerator is a refrigerator that obtains a cooling effect based on the Gifford-McMahon refrigeration cycle by utilizing a volume change of a space by a displacer that reciprocates in a cylinder.

  In the GM refrigerator, a high-pressure refrigerant gas (helium gas or the like) is supplied to a cylinder, and this is adiabatically expanded to a low temperature. The refrigerant gas which has expanded to a very low temperature absorbs heat from the surroundings, and is heated up to room temperature by exchanging heat with the cold storage material and then exhausted from the cylinder. As a result, the inside of the cylinder is kept at a very low temperature. The refrigerant gas discharged from the cylinder is sent to the compressor and compressed to become high-pressure refrigerant gas. This high-pressure refrigerant gas is supplied again to the cylinder of the GM refrigerator.

  In order to supply high-pressure refrigerant gas to the cylinder and to discharge the low-pressure refrigerant gas from the cylinder, there is a switching valve that switches between supply and exhaust of the refrigerant gas in synchronization with the reciprocating movement of the displacer in the cylinder. Used. In the GM refrigerator, a spool valve, a poppet valve, a rotary valve or the like is generally used as a switching valve.

  The rotary valve rotates while rotating the valve plate, which is a cylindrical rotating body, against the valve body. As the valve plate rotates, the passage formed in the valve body and connected to the cylinder is connected to the supply side passage and the exhaust side. It is a mechanism for switching to the passage. Normally, one rotation of the valve plate switches between supply and exhaust once.

  The conventional GM refrigerator is configured to supply a high-pressure refrigerant gas from one side of the valve body, and to switch by a valve plate that rotates while contacting the sliding surface on the opposite side of the valve body (for example, Patent Document 1). Since the valve plate needs to rotate while sealing the refrigerant gas passage formed in the valve plate in surface contact with the valve body, it is necessary to press the valve body and the valve plate against each other. The sliding surface of the valve plate that contacts the surface and the sliding surface of the valve body are surfaces with high flatness, and are formed on the valve plate by pressing the sliding surface of the valve body and the sliding surface of the valve plate together. The refrigerant gas passage is configured to be kept airtight.

In the conventional GM refrigerator, in order to press the valve body against the valve plate, the pressure of the refrigerant gas to be supplied is used. That is, when high-pressure refrigerant gas is introduced from the opposite side of the sliding surface of the valve body, the pressure of the refrigerant gas acts on the surface opposite to the sliding surface of the valve body. The valve body is pressed against the valve plate by a pressure difference between the pressure on the side opposite to the sliding surface of the body and the pressure of the refrigerant gas exhausted on the sliding surface side of the valve body.
JP 2001-280728 A

  When the pressure of the refrigerant gas supplied as described above is used as the pressing force of the rotary valve (that is, the valve body), the pressing force of the valve body depends on the pressure of the refrigerant gas to be supplied and the refrigerant gas to be exhausted. It will be. Therefore, when the pressure of the refrigerant gas varies, the pressing force at the rotary valve also changes.

  When the pressure difference between the refrigerant gas to be supplied and the refrigerant gas to be exhausted is small, the pressing force is also small, and the airtightness is lowered on the sliding surface, and the refrigerant gas may leak from between the sliding surfaces. On the other hand, when the pressure of the refrigerant gas to be supplied is high, the pressing force also increases, and the frictional force on the sliding surface may be excessive.

  When the rotary valve is operated in a state where the pressure of the refrigerant gas is high and the frictional force on the sliding surface is excessive, the sliding surface between the valve body and the valve plate is worn significantly. When continuously operated in such a state, the life of the rotary valve is shortened, and there is a problem that the rotary valve must be replaced early. In addition, there is a problem that wear powder generated by excessive friction between the valve body and the valve plate enters the cylinder and causes a malfunction of the cylinder.

  Further, when the frictional force on the sliding surface is large, there is a problem that the motor for rotating the valve plate is stepped out and the valve plate cannot be normally rotated.

  Further, when the pressing force of the valve body is large, the valve plate must be supported so as to withstand that pressing force. Since the valve plate is a rotating member, it is rotatably supported by a ball bearing. Therefore, when the pressing force of the valve body is large, the thrust load applied to the ball bearing also increases, resulting in a problem that the life of the ball bearing is shortened.

  The present invention has been made in view of the above-described problems, and provides a regenerator type refrigerator having a rotary valve capable of appropriately adjusting the pressing force for pressing the valve main body against the valve plate to closely contact the valve plate. Objective.

In order to achieve the above-described object, according to the present invention, a compressor for compressing a working fluid, a cylinder to which the compressed working fluid is supplied, a compressor and the cylinder are provided, A rotary valve that switches the flow path of the working fluid to one of a gas supply path for supplying the working fluid to the cylinder and a gas discharge path for discharging the working fluid from the cylinder and leading to the compressor; A spring for pressing the valve body of the rotary valve to bring the sliding surface of the valve body into close contact with the sliding surface of the valve plate of the rotary valve, and formed on the opposite side of the sliding surface of the valve body A bypass passage that communicates the first space and the second space connected to the sliding surface of the valve body, and generates a pressing force that acts on the valve body only by the spring load of the spring. then, A gas supply member in which a gas supply hole for supplying a medium gas is formed is provided on the opposite side of the sliding surface of the valve body, and the gas supply hole and the gas flow path of the valve body are connected. A regenerator characterized in that a seal member is provided between the gas supply member and the valve body so that the gas supply hole, the gas flow path, and the first space are hermetically sealed . A refrigerator is provided.

In the regenerator refrigerator according to the present invention, a gas supply member in which a gas supply hole for supplying refrigerant gas is formed is provided on the opposite side of the sliding surface of the valve body, and the gas supply hole and the A gas flow path of the valve main body is connected , and a seal member is provided between the gas supply member and the valve main body so that the gas supply hole, the gas flow path, and the first space are airtight. If sealed, since the second space and the first space is a pressure of the exhaust side are communicated by a bypass passage, it is the pressure of the exhaust side first space.

  Further, the gas supply member has a tip portion extending into the gas flow path of the valve body, and the seal member is formed between an outer peripheral surface of the tip portion and an inner peripheral surface of the gas flow path of the valve body. It is preferable to be provided in between. The bypass passage may be a fine hole formed in a housing that houses the rotary valve.

  According to the present invention, by generating the pressing force of the valve body in the rotary valve only by the spring load of the spring, a constant pressing force can always be applied to the valve body, and the sliding portion between the valve body and the valve plate The wear of the valve body and the valve plate can be suppressed while maintaining the airtightness of the valve, and the life of the rotary valve can be extended. Further, the driving force for rotating the valve plate can be reduced. Further, it is possible to reduce the thrust load applied to the bearing that rotatably supports the valve plate.

  Next, a refrigerator according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a sectional view of a Gifford McMahon (GM) type refrigerator according to a first embodiment of the present invention. The GM refrigerator according to this embodiment includes a gas compressor 1 and a cold head 2. The cold head 2 has a housing part 23 and a cylinder part 10. The gas compressor 1 draws in refrigerant gas from the intake port 1a, compresses it, and discharges it as high-pressure refrigerant gas from the discharge port 1b. Usually, helium gas is used as the refrigerant gas which is a working fluid.

  The cylinder part 10 has a two-stage configuration of a first stage cylinder 10a and a second stage cylinder 10b, and the second stage cylinder 10b is thinner than the first stage cylinder 10a. Displacers 3a and 3b are inserted into the cylinders 10a and 10b, respectively, so as to be able to reciprocate in the axial direction of the cylinder. The displacers 3a and 3b are connected to each other. In the displacers 3a and 3b, gas flow paths filled with the cold storage materials 4 and 5 are formed, respectively.

  A first-stage expansion chamber 11 is formed at the end of the first-stage cylinder 10a on the second-stage cylinder 10b side, and an upper chamber 13 is formed at the other end. A second-stage expansion chamber 12 is formed at the end of the second-stage cylinder 10b opposite to the first-stage cylinder 10a side.

  The upper chamber 13 and the first stage expansion chamber 11 are connected via a gas flow path L1, a gas flow path filled with the regenerator material 4, and a gas flow path L2. The first stage expansion chamber 11 and the second stage expansion chamber 12 are connected via a gas flow path L3, a gas flow path filled with the cold storage material 5, and a gas flow path L4. A cooling stage 6 is attached to a position corresponding to the first stage expansion chamber 11 on the outer peripheral surface of the first stage cylinder 10a. A cooling stage 7 is attached to a position corresponding to the second stage expansion chamber 12 in the outer peripheral surface of the second stage cylinder 10b.

  A seal mechanism 50 is disposed in the vicinity of the end on the upper chamber 13 side in the outer peripheral surface of the first stage displacer 3a. The seal mechanism 50 seals the clearance between the outer peripheral surface of the displacer 3a and the inner peripheral surface of the cylinder 10a.

  A scotch yoke 22 is connected to the first stage displacer 3a and extends outside the cylinder 10a. The scotch yoke 22 is supported by sliding bearings 17a and 17b fixed to the housing 23 so as to be movable in the axial direction of the displacers 3a and 3b. In the sliding bearing 17b, the airtightness of the sliding portion is maintained, and the space in the housing 23 and the upper chamber 13 are isolated. The rotational movement of the motor 15 is transmitted to the displacer 3a via the crank 14 and the scotch yoke 22, and the displacers 3a and 3b are driven to reciprocate.

  When the displacers 3a and 3b move to the upper chamber 13 side, the volume of the upper chamber 13 decreases, and the volumes of the first and second expansion chambers 11 and 12 increase. When the displacers 3a, 3b move in the opposite direction, the increase / decrease in volume is reversed. As the volumes of the upper chamber 13 and the expansion chambers 11 and 12 change, the refrigerant gas moves through the gas flow paths L1 to L4. At this time, heat exchange is performed between the refrigerant gas and the cold storage materials 4 and 5.

  A rotary valve RV is disposed between the intake port 1 a and the discharge port 1 b of the compressor 1 and the upper chamber 13 in the refrigerant gas flow path. The rotary valve RV guides the refrigerant gas discharged from the discharge port 1b of the gas compressor 1 into the upper chamber 13 and guides the refrigerant gas in the upper chamber 13 to the intake port 1a of the gas compressor 1. Switch the refrigerant gas flow path.

  The rotary valve RV has a valve body 8 and a valve plate 9. The valve plate 9 is made of, for example, an aluminum alloy, and the valve body 8 is made of, for example, tetrafluoroethylene (for example, BEAREE FL3000 manufactured by NTN). The valve body 8 and the valve plate 9 have flat sliding surfaces, and the flat sliding surfaces are in surface contact with each other. A thin film made of a hard material such as diamond-like carbon (DLC) is preferably formed on at least one of both sliding surfaces in order to reduce friction and improve wear resistance.

  The valve plate 9 is rotatably supported in the housing 23 by a rotary bearing 16. When the eccentric pin 14a of the crank 14 that drives the scotch yoke 22 revolves around the rotation axis, the valve plate 9 rotates. The valve body 8 is fixed so as not to rotate by the pin 19, but is not fixed in the direction toward the valve plate 9. On the rear side of the valve body 8, a coil spring 20 as an elastic member is disposed in a compressed state with the gas supply member 25. Therefore, the valve body 8 is pressed against the valve plate 9 by the pressing force of the coil spring 20. As a result, the sliding surface of the valve body 8 comes into surface contact with the sliding surface of the valve plate 9 in a state where an appropriate surface pressure is applied. A gas supply hole 25 a formed in the gas supply member 25 communicates with the gas flow path 8 b of the valve body 8, and refrigerant gas is supplied to the valve body 8 from the gas supply hole 25 a.

  Note that the valve plate 9 is supported by a pressing portion by a protrusion of the housing 23. Further, at the time of assembly, although not shown, the housing 23 is divided from the high-pressure gas supply side, and a valve plate is inserted.

  In this embodiment, a coil spring 20 is provided as a pressing force generating means for generating a pressing force of the valve body 8 against the valve plate 9. As the pressing force generating means, a coil spring 20 is suitable, but a spring that is not a coil wound spring or an elastic member such as rubber or plastic is used as long as it is a member that generates an elastic force when compressed. You can also.

  FIG. 2 is an exploded perspective view of the rotary valve RV. The flat sliding surface 8a of the cylindrical valve body 8 and the flat sliding surface 9a of the valve plate 9 are in surface contact. A gas flow path 8 b serving as a gas supply path passes through the valve body 8 along the central axis of the valve body 8. That is, one end of the gas flow path 8b is open to the sliding surface 8a. The other end of the gas flow path 8b is connected to the discharge port 1b of the gas compressor 1 shown in FIG. From the discharge port 1b of the compressor 1 to the gas flow path 8b of the valve body 8 corresponds to a gas supply path.

  A groove 8 c is formed on the sliding surface 8 a of the valve body 8 along an arc centered on the central axis of the valve body 8. One end of the gas flow path 8d formed inside the valve body 8 is open to the bottom surface of the groove 8c. The other end of the gas flow path 8d opens on the outer peripheral surface of the valve body 8, and further communicates with the upper chamber 13 via a gas flow path 21 formed in the housing 23 shown in FIG.

  On the sliding surface 9a of the valve plate 9, a groove 9d extending in the radial direction from the center is formed. When the valve plate 9 rotates and the outer peripheral end of the groove 9d partially overlaps the groove 8c, the gas flow path 8b and the gas flow path 8d communicate with each other via the groove 9d.

  A gas flow path 9 b parallel to the rotation axis extends through the valve plate 9. The gas flow path 9b opens at substantially the same position as the groove 8c formed in the sliding surface 8a of the valve body 8 with respect to the radial direction in the sliding surface 9a. When the valve plate 9 rotates and the opening of the gas flow path 9b partially overlaps the groove 8c, the gas flow path 8d and the gas flow path 9b communicate with each other. The other end of the gas flow path 9b communicates with the intake port 1a of the gas compressor 1 through the cavity in the housing 23 shown in FIG. From the gas flow path of the valve plate 9 to the intake port 1a of the compressor 1 corresponds to the gas discharge path.

  When the gas flow path 8b and the gas flow path 8d communicate with each other via the groove 8c, the refrigerant gas is sent into the upper chamber 13 from the compressor 1. When the gas flow path 8d and the gas flow path 9b communicate with each other, the refrigerant gas in the upper chamber 13 is recovered by the gas compressor 1. Therefore, when the valve plate 9 is rotated, introduction of refrigerant gas into the upper chamber 13 (supply) and recovery of refrigerant gas from the upper chamber 13 (exhaust) are repeated. Both the introduction and recovery of the refrigerant gas and the reciprocating drive of the displacers 3a and 3b are synchronized with the rotation of the crank 14. When the phase of repeated introduction and recovery of the refrigerant gas and the phase of the reciprocating drive of the displacers 3a and 3b are appropriately adjusted, the refrigerant gas becomes extremely cold in the expansion chambers 11 and 12, and an endothermic effect is generated.

  FIG. 3 is a cross-sectional view of the second stage displacer 3b. A lid member 31 is inserted into and bonded to the lower end of the cylindrical member 30 whose upper and lower ends are open. The cylindrical member 30 and the lid member 31 are made of cloth-containing phenol. A wire mesh 32 is disposed on the lid member 31, and a felt plug 33 is disposed thereon.

  On the felt plug 33, for example, a cold storage material 5 formed of small lead balls is filled. Note that a magnetic regenerator material may be used as the regenerator material 5. When a magnetic regenerator material is used, the refrigerating capacity can be increased. A felt plug 34 is disposed on the cold storage material 5, and a punching metal 35 is disposed on the felt plug 34. The punching metal 35 is fixed to the upper part of the inner surface of the cylindrical member 30 by a step provided along the circumference. At the upper end of the cylindrical member 30, a connecting mechanism 36 for connecting to the first stage displacer 3a shown in FIG. 1 is attached.

  An opening 37 for forming a gas flow path is provided on the side wall of the cylindrical member 30 at the height of the wire mesh 32. On the outer peripheral surface above the opening 37 of the cylindrical member 30, a single spiral groove 38 that connects the position of the opening 37 and the upper end is formed. The spiral groove 38 forms a spiral gas flow path in cooperation with the inner surface of the cylinder 10b. For example, the spiral groove 38 has a width of about 2 mm, a depth of about 0.6 mm, and a pitch of about 4 mm.

  The outer diameter of the cylindrical member 30 below the opening 37 is slightly smaller than the outer diameter of the portion above it. Therefore, a gap is formed between the cylindrical member 30 and the second stage cylinder in a portion below the opening 37. This gap forms a gas flow path connecting the inside of the cylindrical member 30 and the expansion space 12 shown in FIG.

  When the refrigerant gas flows into a gap formed between the inner peripheral surface of the cylinder 10b and the outer peripheral surface of the displacer 3b, the refrigerant gas flows along the spiral groove 38. At this time, heat exchange is performed between the refrigerant gas and the cold storage material 5 via the tubular member 30. Since the refrigerant gas flows along a long spiral path, sufficient heat exchange is performed.

  The first stage displacer 3a is also filled with the cold storage material 4 similar to the cold storage material 5, and heat exchange is performed with the refrigerant gas.

  In the regenerator type refrigerator configured as described above, in this embodiment, a pressing force generating means for generating a pressing force acting on the rotary valve RV is provided. In this embodiment, only the pressing force generated by the pressing force generating means acts on the rotary valve RV, and the pressing force due to the pressure of the refrigerant gas does not act. The pressing force generating means according to this embodiment can easily adjust the generated pressing force to an arbitrary strength, and can also function as a pressing force adjusting means.

  4 is an enlarged cross-sectional view of the rotary valve RV shown in FIG. 1 and its surroundings.

  In FIG. 4, the valve body 8 is pressed against the valve plate 9 by the coil spring 20 as described above, and the supply / exhaust of the refrigerant gas is switched by rotating the valve plate 9 while the sliding surface is in close contact therewith. . A gas supply member 25 is fixed to the housing 23 on the opposite side of the sliding surface 8 a of the valve body 8, and a first coil spring 20 is accommodated between the valve body 8 and the gas supply member 25. A space 26 is formed.

  The gas supply member 25 has a gas supply hole 25 a for supplying a refrigerant gas, and the refrigerant gas is supplied from the gas supply hole 25 a to the gas flow path 8 a of the valve body 8. The distal end portion 25b of the gas supply member 25 extends into the gas flow path 8b of the valve body, and a seal member such as an O-ring is provided between the outer periphery of the distal end portion 25b and the inner peripheral surface of the gas flow path 8b. 28 is provided. The first space 26 that is set to the pressure (low pressure) on the exhaust side by the seal member 28, and the gas flow path (gas supply path 25a and gas flow path 8b) through which the refrigerant gas (high pressure) supplied to the cylinder passes. The space between them is hermetically sealed. The seal member may be provided between the opposing surfaces of the valve body 8 and the gas supply member 25. However, the valve body 8 is slightly displaced in the axial direction and no pressing force is applied to the valve body by the seal member. For these reasons, it is preferable to seal between the outer peripheral surface of the tip portion 25b and the inner peripheral surface of the gas flow path 8b.

  The refrigerant gas from the compressor 1 supplied to the gas supply path 25 a of the gas supply member 25 passes through the gas flow path in the valve plate 9 from the gas flow path 8 b of the valve body 8, and the gas flow formed in the housing 23. It is introduced into the upper chamber 13 via the passage 21.

  In the present embodiment, the first space 26 that accommodates the coil spring 20 and the second space 27 formed on the sliding surface side of the valve body 8 are bypass passages 24 formed of pores formed in the housing 23. It is communicated by. Therefore, the pressure of the refrigerant gas in the second space 27 formed on the sliding surface side of the valve body 8 is transmitted to the first space 26 through the bypass passage 24. As a result, the first and second spaces 26 and 27 on both sides of the valve body 8 are equal in pressure (exhaust side pressure), so that the valve body 8 is not pressed by the pressure of the refrigerant gas. Therefore, in this embodiment, the pressing force for pressing the valve body 8 against the valve plate 9 is only the spring load by the coil spring 20.

  In the present embodiment, the bypass passage 24 is formed in the housing 23 so that the first and second spaces 26 and 27 have the same pressure, but from the high-pressure gas supply side of the valve body 8 (that is, the first space A hole is formed in the axial direction (from a portion facing the space 26), and a radial hole is formed in the side surface of the valve body 8 immediately before reaching the valve plate 9 to communicate with the second space 27. The two spaces may have the same pressure.

  Conventionally, there is no bypass passage 24, and the valve body 8 is pressed by pressure in a space to which the refrigerant gas is supplied (corresponding to the first space 26). However, in this embodiment, the bypass passage 24 is used. Thus, the pressure of the refrigerant gas on the exhaust side is guided to the first space 26 on the rear side of the valve body 8 so that the valve body 8 is not pressed by the pressure of the refrigerant gas. Accordingly, a constant and appropriate pressing force can be applied to the valve body 8 at all times by the coil spring 20 without the pressing force of the valve body 8 changing due to the fluctuation of the pressure of the refrigerant gas.

  The pressing force that acts on the valve body 8, that is, the pressing force that presses the sliding surface 8a of the valve body 8 against the sliding surface 9a of the valve plate 9, causes the refrigerant gas to leak from between the sliding surfaces 8a and 9a. It is sufficient if the pressing force is not so high. If the pressing force is excessive, wear of the sliding surfaces 8a and 9a increases, and the life of the rotary valve RV is shortened. In the present embodiment, for example, by adjusting the free length of the coil spring 20, adjusting the compression length of the coil spring 20, or adjusting the spring constant of the coil spring 20, the pressing force acting on the valve body 8 is adjusted. Can do. Therefore, it is possible to easily adjust the pressing force so that there is no leakage from the sliding surfaces 8a and 9a and the sliding surfaces 8a and 9a are less worn.

  The inventor changed the spring load of the coil spring 20 that presses the valve main body 8 (that is, the pressing force of the coil spring 20) in the regenerator type refrigerator using the rotary valve RV described above to change the regenerator type refrigerator. Was obtained. FIG. 5 is a graph showing the results. In the example shown in FIG. 5, the spring load of the coil spring 20 was set in three stages of 2.2 kgf, 19.0 kgf, and 35.0 kgf, and the refrigeration capacity obtained by operating the regenerator type refrigerator was measured. As can be seen from FIG. 5, when the spring load was set to 2.2 kgf, the refrigerating capacity was the smallest, and it was estimated that the refrigerant gas leaked from the rotary valve RV. When the spring load was set to 19.0 kgf, the refrigeration capacity of 50 k to 70 k increased by 2 to 1.5 times compared to when the spring load was 2.2 kgf. It was estimated that the leakage of refrigerant gas from the rotary valve RV was considerably reduced. Therefore, when the spring load was set to 35.0 kgf, the refrigeration capacity increased compared to the case where the spring load was 19.0 kgf, but the increase was about 1.2 times. Thereby, when the spring load was 35.0 kgf, it was estimated that the leakage of the refrigerant gas from the rotary valve almost disappeared.

  Therefore, only the spring load of 35.0 kgf was applied to the valve body without applying the refrigerant gas pressure and the refrigeration capacity when the pressure of the refrigerant gas was applied to the valve body 8 as in the past instead of the spring load. The refrigeration capacity of the case was measured. FIG. 6 is a graph showing the measurement results of the refrigerating capacity. As can be seen from FIG. 6, the refrigeration capacity when the pressure of the refrigerant gas is applied to the valve body as in the prior art (gas pressure hermeticity, load of about 150 kgf) and the spring of 35.0 kgf without applying the pressure of the refrigerant gas The refrigeration capacity when only the load is applied to the valve body (spring force airtightness) is almost the same, and if a 35.0 kgf spring load is applied to the valve body, the same airtightness as before can be maintained. I understood.

  As described above, the pressing force generating means in this embodiment is provided with the bypass passage 24 for equalizing the pressures in the first and second spaces 26 and 27, and the spring load of the coil spring 20 that presses the valve body 8 is applied. This is achieved by adjusting, and the life of the rotary valve RV can be extended as compared with the conventional case where the valve body 8 is pressed by the pressure of the refrigerant gas. Moreover, since wear of the sliding surfaces 8a and 9a is suppressed, it is possible to prevent problems caused by mixing of wear powder into the refrigerant gas.

  Further, since the frictional force of the sliding surfaces 8a and 9a is reduced, the torque applied to the motor 15 for rotationally driving the valve plate 9 is reduced. Therefore, an excessive torque is not applied to the motor 15, and the motor 15 can always be driven normally. In addition, the motor 15 can be a smaller motor (a motor with a small output torque).

  Furthermore, since the pressing force of the valve body 8 can be reduced, the pressing force applied to the valve plate 9 can also be reduced. Therefore, it is possible to reduce the thrust load applied to the rotary bearing 16 composed of a ball bearing or the like that rotatably supports the valve plate 9, thereby extending the life of the rotary bearing 16.

  Further, even when the pressure on the exhaust side of the refrigerant gas becomes larger than the pressure on the supply side, a reverse pressing force acts on the valve body 8 as in the conventional case, so that the valve body 8 is removed from the valve plate 9. There is no such thing as going away. Both the valve plate 9 and the valve body 8 are connected by a bypass passage 24 and are disposed in a space that is always at the exhaust side pressure, and the pressing force acting on the valve body 8 due to the pressure difference of the refrigerant gas. This is because it does not occur.

  The above-described embodiment is an example in which the present invention is applied to a two-stage type Gifford McMahon (GM) type refrigerator, but the present invention is not limited to a two-stage type, and may be a single-stage type or a multi-stage type. It can also be applied to a GM refrigerator.

1 is a cross-sectional view of a Gifford McMahon refrigerator according to a first embodiment of the present invention. It is a disassembled perspective view of the rotary valve shown in FIG. It is sectional drawing of the 2nd step | level displacer 3b shown in FIG. It is sectional drawing which expands and shows the rotary valve shown in FIG. 1, and its circumference | surroundings. It is a graph which shows the change of the refrigerating capacity when changing a spring load. It is a graph which shows the refrigerating capacity obtained by press by refrigerant gas pressure, and the refrigerating capacity obtained by press only by spring load.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Gas compressor 3a, 3b Displacer 4,5 Cold storage material 6,7 Cooling stage 8 Valve body 9 Valve plate 8a, 9a Sliding surface 10 Cylinder part 10a, 10b Cylinder 11, 12 Expansion chamber 13 Upper chamber 14 Crank 15 Motor 16 Rotating bearings 17a, 17b Sliding bearing 19 Pin 20 Coil spring 21 Gas flow path 22 Scotch yoke 23 Housing 24 Bypass path 25 Gas supply member 26 First space 27 Second space 28, 29 Seal member 30 Cylindrical member 31 Lid member 32, 35 Wire mesh 33, 34 Felt plug 36 Connection mechanism 38 Spiral groove 50 Seal mechanism

Claims (3)

A compressor for compressing the working fluid;
A cylinder to which the compressed working fluid is supplied;
Provided between the compressor and the cylinder, the working fluid flow path is a gas supply path for supplying the working fluid to the cylinder, and the working fluid is discharged from the cylinder and led to the compressor. A rotary valve that switches to one of the gas discharge paths;
A spring for pressing the valve body of the rotary valve to bring the sliding surface of the valve body into close contact with the sliding surface of the valve plate of the rotary valve;
A bypass passage communicating a first space formed on the opposite side of the sliding surface of the valve body and a second space connected to the sliding surface of the valve body;
Generating a pressing force acting on the valve body only by the spring load of the spring ;
A gas supply member having a gas supply hole for supplying a refrigerant gas is provided on the opposite side of the sliding surface of the valve body, and the gas supply hole is connected to a gas flow path of the valve body. A regenerator characterized in that a seal member is provided between the gas supply member and the valve body so that the gas supply hole, the gas flow path, and the first space are hermetically sealed . Type refrigerator. A regenerator type refrigerator according to claim 1 ,
The gas supply member has a tip portion extending into the gas flow path of the valve body, and the seal member is between an outer peripheral surface of the tip portion and an inner peripheral surface of the gas flow path of the valve body. A regenerator-type refrigerator that is provided. A regenerator type refrigerator according to claim 1 ,
The regenerator-type refrigerator, wherein the bypass passage is a pore formed in a housing that houses the rotary valve.

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