JPH0343546B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a Stirling cycle refrigerator equipped with a radial piston compressor.

(Prior Art) It is well known that in a Stirling cycle refrigerator, it is necessary to cause a compression piston and a displacer to reciprocate under a constant phase difference. Drive methods for the compression piston and displacer to generate such motion include crankshaft drive, rotating swash plate drive, Rhombik drive,
Linear drive systems and the like are known, but among these, the Rhombic drive system and the linear drive system are drive systems for single cylinders and are not suitable for multi-cylinder systems.

Therefore, conventional techniques are known in which the crankshaft drive system (see Japanese Patent Application Laid-open No. 58-69366) or the rotary swash plate drive system (see Japanese Patent Application Laid-Open No. 54-149958) is used for multi-cylinder applications.

The above crankshaft drive system is constructed by arranging multiple cylinders coaxially in series and connecting the compression piston inserted in one cylinder and the displacer inserted in the other cylinder in the axial direction. The above rotating swash plate drive system has a plurality of cylinders arranged concentrically, and a compression piston inserted into one cylinder and a displacer inserted into the other cylinder are arranged parallel to each other. It is composed of Both of these types can be made to have multiple cylinders relatively easily.

(Problems to be Solved by the Invention) However, the above-mentioned prior art has a complicated structure, and in order to obtain a large output, there is a problem that the overall weight and size must be increased. In particular, the rotating swash plate drive system is generally suitable for small refrigerators.
It is necessary to increase the diameter of the swash plate in accordance with the piston diameter, and it is also necessary to increase the strength of the swash plate and the bearing portion accordingly, which inevitably increases the size of the device.

The present invention was made to solve the above-mentioned conventional problems, and an object of the present invention is to provide a multi-cylinder Stirling cycle refrigerator that has a simple structure, is compact, lightweight, and can provide a large output.

(Means for Solving the Problems) In order to achieve the above object, the present invention makes the body of a crankshaft that is rotationally driven by a drive machine eccentric, and rotatably fits an outer ring into this body, and radially rotates the crankshaft. A radial piston drive device is constructed by connecting connecting rods of a plurality of compression pistons arranged in the outer ring to the outer ring. In addition, multiple displacers are arranged concentrically with the crankshaft,
A cam groove that is displaceable in the axial direction of the crankshaft is provided on the outer periphery of a cam member fixed to one end of the crankshaft, and a drive body is inserted into this cam groove to reciprocate the displacer in the axial direction of the crankshaft. A displacer driving device is constructed by connecting a moving rod to the driving body. The shape of the cam groove is set so that the phase of the displacer corresponding to each compression piston can advance approximately 90 degrees.

(Function) According to the present invention, a radial piston drive device and a displacer drive device having a plurality of displacers arranged concentrically with the crankshaft of the piston drive device are combined to produce a Stirling cycle refrigeration system. With this structure, even if the number of compression pistons and displacers is increased to improve the refrigerating capacity, the overall size of the refrigerating machine can be avoided.

Furthermore, since a radial piston drive device is employed, most of the gas compression load is canceled out on the crankshaft, making it possible to maintain the balance of compression forces relatively easily. Therefore, the load on the bearing section that supports the crankshaft can be reduced, so that the casing and the bearing section can be made more compact as a whole.

In addition, since the compression pistons are arranged radially, even if the diameter of the pistons is increased, the overall size of the device does not increase. Therefore, the output can be easily increased.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a longitudinal sectional view of a Stirling cycle refrigerator. In the figure, a Stirling cycle refrigerator 1 has a radial piston drive device 2.
and a displacer drive device 3 are connected to each other.

The piston drive device 2 includes a drive machine 6, and the drive machine 6 drives the crankshaft 4 via a reduction gear 5.
is connected to. The speed reducer 5 is, for example, a planetary gear mechanism or a bevel gear mechanism. The reducer 5 and the drive unit 6 have an airtight structure so that the working gas within the system does not leak. The crankshaft 4 vertically passes through an airtight crankcase 7, and is rotatably supported within the crankcase 7 by low vapor pressure, grease-sealed roller bearings 8a and 8b. An oil seal 8c is provided in the crankcase 7 to prevent lubricating oil in the reduction gear 5 from entering.

The body 9 of the crankshaft 4 has a larger diameter than the crankshaft 4 and is eccentric with respect to the crankshaft 4. The diameter and eccentric width of the body 9 are the same as those of the compression piston 1.
It is selected according to the stroke of 7. This body 9 has a low vapor pressure grease-sealed roller bearing 1.
An outer ring 11 is rotatably fitted through the outer ring 11. A sliding surface 13a of a connecting rod 13 connected to a compression piston 17 is in sliding contact with the outer peripheral surface of the outer ring 11. A non-lubricated material is fixed to the sliding surface 13a with a constant thickness. The non-lubricated material is selected to have good sliding properties and wear resistance, such as a polymer bearing material or a sintered bearing material. Note that 12 is an oil seal.

The connecting rod 13 extends radially in the radial direction of the outer ring 11.
are arranged. A pair of guide rings 14a and 14b made of a lubricant-free material are fitted into the lower end flange portion 13b of each connecting rod 13. The guide rings 14a and 14b maintain the contact state between the sliding surface 13a of each connecting rod 13 and the outer ring 11, and also prevent the connecting rod 13 from swinging in the direction indicated by arrow A and the outer ring 11 from moving in the axial direction ( Sliding in the same direction as A) is prevented. Moreover, the guide ring 14a,
14b, the sliding friction heat between the outer ring 11 and the sliding surface 13a is transmitted to the crankcase 7, and the low temperature near the sliding surface 13a is maintained.

As shown in FIG. 2, four compression piston cylinders 18 are provided radially projecting from the crankcase 7 at equal intervals in the circumferential direction. The compression piston 17 in each cylinder 18 is connected to the spherical head 13c of the connecting rod 13 via two spherical bearings 19a, 19b. Spherical bearing 19
a and 19b are made of a polymer-based or sintered metal-based non-lubricated material. Further, the piston ring 22 and the rider ring 23 are made of an alloy resin-based non-lubricated material. A scraper ring 24 having a dustproof function is attached to the compression piston 17 to prevent dust from entering the compression chamber 20 due to wear of the guide rings 14a, 14b (FIG. 1) and the sliding surface 13a. ing.

A compression chamber 20 in the cylinder 18 and a back chamber 21 in the crankcase 7 are filled with a working gas as a refrigerant, such as _He gas. This compression chamber 20 is constantly filled with the inertia of the compression piston 17, the piston ring 22, and the rider ring 2 during operation.
A load that overcomes the frictional force of 3 acts, and the connecting rod 13 and outer ring 11 are in contact with each other with the compressive load. Note that 25a and 25b are cooling water passages for the cylinder 18, and the cooling water absorbs the compression heat of the working gas, the sliding friction heat of the rings 22 and 23, and the sliding friction heat of the spherical bearings 19a and 19b, respectively. Ru.

Next, the configuration of the displacer drive device 3 will be explained. A cam member 30 coaxial with the crankshaft 4 is provided at the upper end of the crankshaft 4 in FIG. A key 31 is provided between the crankshaft 4 and the cam member 30 to make the rotational movements of the two the same.
is inserted. On the outer peripheral surface of the cam member 30,
A cam groove 32 with a rectangular cross section extending in the circumferential direction is formed. The cam groove 32 is curved in a sinusoidal shape in the circumferential direction, and four roller-shaped driving bodies 33 are inserted into the cam groove 32 at equal intervals in the circumferential direction. . Each drive body 33 is rotatable about an axis perpendicular to the crankshaft 4 by a grease-sealed roller bearing (not shown), and is connected to four rods 34 concentrically with the crankshaft 4 by bolts and bolts. They are individually fastened with nuts 95. Each rod 34 extends coaxially with the crankshaft 4 and is reciprocatably supported within the airtight casing 28 by low vapor pressure, grease-sealed bearings 36a, 36b.

Each rod 34 is individually connected to each displacer 41 in four displacer cylinders 40 extending coaxially with the rod 34.
The displacer 41 has a relatively large diameter first displacer 41 connected to the tip of the rod 34.
a, and a relatively small-diameter second displacer 41b connected to the first displacer. 1st
An airtight back chamber 42 is provided at the connection between the displacer 41a and the rod 34, and this back chamber 42 is connected to the compression chamber in the compression piston cylinder 18 via a passage 43 and a heat exchanger 44. It is connected to 20. The heat exchanger 44 is configured by incorporating a plurality of water cooling pipes.

Inside the first displacer 41a, a first regenerator 38a made up of layered wire mesh (cold storage material) is incorporated, and inside the second displacer 41b, lead particles (cold storage material) are incorporated. A second regenerator 38b filled with water is incorporated. 1st displacer 4
1a and the second displacer 41b is provided with an airtight first expansion chamber 46a, and in the vicinity of this first expansion chamber 46a, a first expansion chamber of each of the displacer cylinders 40 is provided. A first annular cold head 47a is provided which communicates with all of the cold heads 46a. Further, an airtight second expansion chamber 46b is provided at the tip of the second displacer 41b, and each second expansion chamber of the displacer cylinder 40 is provided in the vicinity of the second expansion chamber 46b. An annular second cold head 47 that communicates with all of 46b.
b is provided. First and second expansion chambers 46
a, 46b are the first and second regenerators 38a, 3
It communicates with the back chamber 42 on the rod 34 side via 8b.

Next, the operations of the radial piston drive device 2 and the displacer drive device 3 will be explained.

First, when the drive device 6 is activated, the crankshaft 4 is reduced to a constant rotational speed by the reduction gear 5 and driven to rotate. The rotational movement of the eccentric body 9 of the crankshaft 4 is converted into a reciprocating movement of the connecting rod 13 via a roller bearing 10 and an outer ring 11. Due to the eccentricity of the body 9, the four compression pistons 17 reciprocate within the cylinder 18 with a phase difference of 90 degrees.

On the other hand, the rotational torque of the crankshaft 4 is transmitted to the cam member 30 and converted into reciprocating motion of the rod 34 via the drive body 33 inserted into the cam groove 32 of the cam member 30. Due to the sinusoidal shape of the cam groove 32, the four displacers 41 move toward the cylinder 40 90 degrees ahead of the phase of the corresponding compression piston 17.
Each moves back and forth inside.

Next, four steps per cycle of the Stirling cycle refrigerator 1, that is, an isothermal compression step, an isovolume step,
The isothermal expansion process and the isovolume process will be explained.

First, in the isothermal compression process, when the compression piston 17 rises from a state where the displacer 41 is located at the upper end of the displacer cylinder 40 and the compression piston 17 is located at the lower end of the compression piston cylinder 18, the compression chamber The working gas in 20 is compressed and flows into back chamber 42 through heat exchanger 44 and passage 43 . At this time, a part of the generated gas compression heat is absorbed by the water-cooled cylinder 18, and the remaining compression heat is absorbed by the heat exchanger 44, so ideally, the compression process is an isothermal compression process.

Next, in the equal volume process, the displacer 4
1 descends, the working gas in the back chamber 42 passes through the first regenerator 38a and flows into the first expansion chamber 46a, and some of the working gas flows into the second regenerator 38a.
8b and flows into the second expansion chamber 46b.
At this time, the working gas is supplied to the first and second regenerators 3
When passing through the regenerators 8a and 38b, the regenerator absorbs heat and is cooled, and the pressure also decreases, becoming a low-temperature gas at a predetermined pressure in the first and second expansion chambers 46a and 46b. This is an isovolumic change with a constant volume.

Next, in the isothermal expansion step, when the compression piston 17 descends, the first and second expansion chambers 46
The low temperature gas inside a and 46b cools down due to expansion. At this time, the first and second cold heads 4
Heat is removed from 7a and 47b, and the low-temperature gas eventually expands isothermally at a constant temperature. The amount of heat taken by the low temperature gas is the refrigeration output of the refrigerator 1.

Next, in the equal volume process, the displacer 4
1 rises, the first and second expansion chambers 46a,
The low temperature gas in 46b is transferred to the first and second regenerators 3
8a, 38b, flows into the rear chamber 42 on the rod 34 side, and further flows into the compression chamber 20 through the heat exchanger 44. At this time, the low-temperature gas cools each of the regenerator materials in the first and second regenerators 38a and 38b, becomes high in temperature, and increases in pressure. This is an isovolumic change with a constant volume.

By repeating the above series of operations, a continuous high refrigeration output can be obtained in the first and second cold heads 47a and 47b.

In the above configuration, a radial piston drive device 2 and a plurality of displacers 4 arranged concentrically with the crankshaft 4 of the piston drive device 2 are provided.
Since the Stirling cycle refrigerator 1 is constructed by combining the displacer drive device 3 with the displacer drive device 3 having the Enlargement can be avoided.

In addition, since the compression pistons 17 driven by the eccentric crank mechanism are arranged radially, most of the gas pressure load in the compression piston cylinder 18 is offset, reducing the compression load on the bearing section that supports the crankshaft 4. can do. Therefore, the bearing portion and the crankcase 7 can be made more compact.

Furthermore, since the gas pressure load is canceled out, the diameter of the compression piston 17 can be increased, thereby increasing the output. Moreover,
Since the compression piston cylinders 18 are provided radially, the size of the entire refrigerator in the axial direction (vertical direction in FIG. 1) does not increase even if the cylinder diameter is increased. Further, since the radial piston compressor has a structure that is flat with respect to the axial direction of the crankshaft 4, it is advantageous in reducing the axial dimension.

In addition, in this embodiment, the inside of the system is made oil-free by the method described below, so that the service life is extended without oil supply and the structure is simplified. Even if it were to enter the compression chamber 20, contamination of the interior is prevented. This prevents contamination of cold storage materials,
Improved heat transfer and lower compression losses are achieved,
The performance and reliability of the refrigerator 1 are improved. That is, although the eccentric body 9 of the crankshaft 4 has a fairly high circumferential speed, since the grease-sealed roller bearing 10 with a small coefficient of friction is provided on the outer peripheral surface of the body 9,
Frictional work in this part can be significantly reduced. Furthermore, since the outer ring 11 hardly rotates due to the roller bearing 10, the relative movement of the sliding surface 13a of the connecting rod 13 with respect to the outer peripheral surface of the outer ring 11 can be reduced. Therefore, the sliding surface 13a can be made of a lubricant-free material.

For these reasons, this refrigerator structure is more efficient than conventional crankshaft drive systems or rotating swash plate drive systems.
Larger size, more compact size, lighter weight, and multiple cylinders can be easily achieved.

Furthermore, since the cam member 30 is used as a method of driving the displacer 41, the cam member 30
By appropriately changing the shape of the cam groove 32 within a range that does not impede the reciprocating motion of the drive body 33 and the rod 34, it is possible to easily achieve the most thermodynamically preferable reciprocating motion of the displacer 41.
Further, since the piston drive device 2 and the displacer drive device 3 are connected by the key 31 provided between the crankshaft 4 and the cam member 30, each reciprocation of the compression piston 17 and the displacer 41 is The phase difference of motion can be arbitrarily selected. This phase difference greatly affects the refrigeration output. In an ideal state, the phase difference is 0 degrees and the refrigeration output is zero;
Refrigeration output is maximum at 90 degrees. However, in reality, the optimum value exists near 90 degrees, which is slightly outside 90 degrees due to pressure loss and other factors.

FIG. 3 shows a second embodiment, in which the sliding surface 13a of the connecting rod 13 is in contact with the body 9 via a needle bearing 60 having the same curvature as the outer peripheral surface of the body 9. The other configurations are the same as the first embodiment shown in FIG. The bearing 60 is a grease-sealed type with an oil seal 64, and the retainer 62 is a fourth
As shown in the figure, the sliding surface 1 is fixed by the mounting bolt 63.
It is fixed on the 3a side. Since the bearing 60 performs rolling frictional motion while contacting the outer peripheral surface of the body 9, the frictional work is small and mechanical efficiency is improved.

FIG. 5 shows a third embodiment, in which a main connecting rod 70 is fixed to the outer ring 11 with a mounting bolt 73. The other sub connecting rod 72 has a pin 75 attached to the bracket portion 11a of the outer ring 11, as shown in FIG.
and are connected by a bearing 76. Bearing 76
A non-lubricated cylindrical bearing or spherical bearing is used. The main connecting rod 70 can reciprocate while rocking together with the outer ring 11, and the other sub connecting rod 72 can reciprocate while rocking in conjunction with the outer ring 11. Note that 77 is a split pin.

FIG. 7 shows a fourth embodiment, in which a circular swash plate 80 is fixed to the tip of the crankshaft 4 in place of the cam member 30 of the first embodiment. Swash plate 8
The center axis of the crankshaft 4 is inclined with respect to the center axis of the crankshaft 4, and a cam groove 81 with a rectangular cross section extending in the circumferential direction is formed on the outer peripheral surface of the swash plate 80. A ring-shaped receiving plate 82 that is concentric with the swash plate 80 is fitted into the cam groove 81 . Receiving plate 8
2 is a thrust bearing 83 and a radial bearing 84
is rotatably supported within the cam groove 81. One end of a connecting rod 85 corresponding to the displacer 41 is connected to the receiving plate 82 via a pin 93a. Each other end of the connecting rod 85 is connected to a piston 86 via a pin 93b, and the piston 86 is connected to the displacer 41, respectively.

The axial load applied to the receiving plate 82 is transmitted to the crankcase 7 via the thrust bearing 83, the swash plate 80, the crankshaft 4, and the roller bearing 8b.
Since only the differential pressure between the back chamber 42 and each expansion chamber 46a, 46b is applied to the receiving plate 82 and the swash plate 80,
The swash plate 80 and the bearing 8b do not need much strength. Therefore, compared to the conventional rotary swash plate drive system, it is possible to achieve an overall reduction in size and weight. Note that 91 is a non-lubricated bearing;
2 is a side plate bolted to the thrust bearing 83.

(Effects of the Invention) As explained above, according to the present invention, the displacer drive includes a radial piston drive device and a plurality of displacers arranged concentrically with the crankshaft of the piston drive device. Since the refrigerator is constructed by combining these devices, even if the number of compression pistons and displacers is increased in order to improve the refrigerating capacity, it is possible to avoid increasing the size of the refrigerator as a whole.

Additionally, since the compression pistons are arranged radially, most of the gas pressure loads in each cylinder are offset. Therefore, the bearing portion and the casing can be made lightweight and compact. Furthermore, even if the cylinder diameter is increased in order to increase the output, the device is prevented from becoming complicated or large.

Therefore, it is possible to obtain a multi-cylinder Stirling cycle refrigerator that has a simple structure, is compact, lightweight, and has a high output.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing a first embodiment of the invention, FIG. 2 is a sectional view taken along the line - in FIG. 1,
FIG. 3 is a longitudinal cross-sectional view showing a second embodiment of the invention;
Fig. 4 is a sectional view of the vicinity of the needle bearing, Fig. 5 is a vertical sectional view showing a third embodiment of the invention, Fig. 6 is a sectional view taken along the - line in Fig. 5, and Fig. 7 is a sectional view of the invention. FIG. DESCRIPTION OF SYMBOLS 1... Stirling cycle refrigerator, 2... Radial piston drive device, 3... Displacer drive device, 4... Crankshaft, 6... Drive machine,
9... Body, 11... Outer ring, 13... Connecting rod, 1
7... Compression piston, 30... Cam member, 32...
...Cam groove, 33...Driver, 34...Rod, 3
8a, 38b...Regenerator, 41...Displacer, 42...Back chamber, 44...Heat exchanger, 46
a, 46b...expansion chamber.

Claims (1)

[Claims] 1. The refrigerant compressed by the compression piston is sent through a heat exchanger to the rear chamber on one side of the displacer, passes through a regenerator in the displacer, and is expanded on the other side of the displacer. In a Stirling cycle refrigerator that lowers the temperature of refrigerant by flowing into a chamber, a plurality of compression pistons are arranged radially, and an outer ring is rotatably fitted into the eccentric body of a crankshaft that is rotationally driven by a drive machine. A radial piston drive device comprising a connecting rod of a compression piston connected to the cam member, and a plurality of displacers arranged concentrically with the crankshaft, the outer periphery of a cam member being fixed to one end of the crankshaft. A cam groove that is displaced in the axial direction of the crankshaft is provided, and a rod that reciprocates the displacer in the axial direction of the crankshaft is connected to the drive body inserted into this cam groove, and and a displacer drive device in which the shape of the cam member is set so that the phase of the corresponding displacer advances by approximately 90 degrees.