JPH0416122Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to an oil-fed 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 systems 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.

Conventionally, techniques using the above-mentioned crankshaft drive system (see Japanese Patent Application Laid-open No. 58-69366) or rotating swash plate drive system (see Japanese Patent Application Laid-Open No. 54-149958) are known.

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 has the problem of increasing the overall weight and size in order to obtain a large output. 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 according to the piston diameter, and the strength of the swash plate and bearing part must be increased accordingly, so increasing the output inevitably increases the size of the device. .

This invention was made to solve the above-mentioned conventional problems, and the purpose is to provide a multi-cylinder oil-fed Stirling cycle refrigerator that is simple in structure, compact, lightweight, and highly reliable. do.

(Means for Solving the Problems) In order to achieve the above object, this invention radially arranges a plurality of compression pistons and a guide piston coaxially connected to each compression piston,
By rotatably providing a roller on each guide piston and bringing the roller into contact with the outer circumferential surface of the eccentric body of the crankshaft that is rotationally driven by a drive machine,
It constitutes a radial piston drive device.
In addition, a plurality of displacers are arranged concentrically with the crankshaft, and 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. A displacer drive device is constructed by inserting a drive body and connecting a rod for reciprocating the displacer in the axial direction of the crankshaft to the drive body. The shape of the cam groove is set so that the phase of the displacer corresponding to each compression piston can be advanced by approximately 90 degrees. Further, a lubricating oil supply device is provided for supplying lubricating oil to the contact surface between the body and the roller.

(Function) According to this invention, a radial piston drive device and a displacer drive device having a plurality of displacers arranged concentrically with the crankshaft of this piston drive device are combined to produce Stirling cycle refrigeration. 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 mechanism is adopted, most of the gas compression load is canceled out in each compression chamber, 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.

In addition, since a guide piston is interposed between the compression piston and the body, the guide piston is brought into contact with the outer peripheral surface of the roller body, and lubricating oil is supplied to the contact surface. can be prevented from occurring. Furthermore, since the frictional force is reduced by the rollers, the driving torque of the body can also be reduced, and it is possible to prevent the driving machine from increasing in size. Furthermore, since the inside of the back chamber of the compression piston is always kept clean by the oil scrubber ring provided on the guide piston, it is possible to prevent the refrigerant gas in the cylinder from being contaminated by oil. This prevents oil from contaminating the refrigerant gas, preventing contamination of the inside of the heat exchanger and regenerator material, reducing heat transfer performance, and increasing pressure loss, resulting in improved refrigeration performance. It will be done.

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

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

The piston drive device 2 includes a speed reducer 5 and a drive device 6, and the speed reducer 5 is, for example, a planetary gear mechanism or a bevel gear mechanism. One end of the drive shaft (not shown) of the reducer 5 is connected to a crankshaft 4 that extends in a direction perpendicular to the direction in which the drive device 6 and the reducer 5 are connected (left-right direction in FIG. 1). ,
The other end of the rotating shaft opposite to the crankshaft 4 is connected to a lubricating oil pump 70 with a pressure regulating valve. The lubricating oil pump 70 is driven by the speed reducer 5 and plays the role of pumping and supplying lubricating oil to an oil supply section 71 (FIG. 2), which will be described later. crankshaft 4
penetrates the inside of the airtight crankcase 7 vertically, and is rotatably supported within the crankcase 7 by roller bearings 8a and 8b. crankshaft 4
The body 9 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 portion 9 are selected depending on the stroke of the pumping piston 17.

As shown in FIG. 2, the crankcase 7 includes four guide piston cylinders 11 and four compression piston cylinders 18 coaxially connected to each cylinder 11 in the radial direction of the crankshaft 4. It is installed in a radial manner. The guide piston cylinder 11 and the compression piston cylinder 18 each extend in the radial direction of the crankshaft 4, and the compression chamber 20 of the cylinder 18 is filled with a working gas as a refrigerant, such as He gas. . Each compression piston 17 in the cylinder 18 is connected to each guide piston 1 in the cylinder 11 via the piston rod 13.
2 are connected to each other. Piston rod 13
are prevented from coming off from the compression piston 17 and the guide piston 12 by the flange portions 13a and 13b, respectively. Further, 13c and 13d are push plates that take on the compressive load of the working gas.

A pin 14 having an axis parallel to the rotational axis of the body 9 is fixed to the lower end of the guide piston 12, and a cylinder concentric with the pin 14 is attached to the pin 14 via a radial bearing 15. A shaped roller 16 is rotatably fitted therein. During operation, the roller 16 is constantly pressed against the outer peripheral surface of the body 9 by the gas pressure in the compression chamber 20, overcoming the inertial force of the compression piston 17 and the frictional force of the piston ring 22 and rider ring 23. . As the radial bearing 15, for example, a low vapor pressure grease-sealed roller bearing or a spherical bearing made of a non-lubricated material is used.

As shown in FIG. 1, the guide piston 12 has a guide groove 8 extending along its axial direction on its outer circumferential surface.
0 is formed, and a key 81 fixed to the guide piston cylinder 11 is slidably fitted into this guide groove 80. The key 81 prevents the guide piston 12 from rotating around its axis, so that the axis of the roller 16 is always kept parallel to the axis of rotation of the body 9. In addition, 8
5 is a guide bearing, and 79 is an oil paddle ring.

As shown in FIG. 2, the space between each guide piston cylinder 11 in the crankcase 7 has a double structure of an outer wall 7a and an inner wall 7b, and both walls 7a and 7b are connected to supply oil. A portion 71 is provided respectively. Each outer end 71a of the oil supply section 71 communicates with the lubricating oil pump 70 (Fig. 1) via a pipe (not shown), and each nozzle hole 74 on the inner end 71b side communicates with the lubricant pump 70 (Fig. 1) through a pipe (not shown). They are arranged facing into the chamber 75 and facing the body 9, respectively.

Further, as shown in FIG. 1, the crankcase 7 is provided with an oil drain hole 76 for guiding the lubricating oil supplied into the crank chamber 75 to the lubricating oil pump 70 side. Note that 25a and 25b are cooling water passages for each cylinder 11 and 18.

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 fitted between the crankshaft 4 and the cam member 30 for transmitting rotational motion. A cam groove 32 having a rectangular cross section and extending in the circumferential direction is formed on the outer peripheral surface of the cam member 30. The cam groove 32 is curved in a sinusoidal shape in the circumferential direction, and four roller-shaped drive bodies 33 are installed in the cam groove 32 at equal intervals in the circumferential direction.
is inserted. Each drive body 33 is connected to the crankshaft 4 by a grease-sealed roller bearing (not shown).
The four rods 34 are individually fastened by bolts and nuts 95 to four rods 34 arranged concentrically with the crankshaft 4 so as to be rotatable about an axis perpendicular to the crankshaft 4 . Each rod 34 extends coaxially with the crankshaft 4 and is reciprocably 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, each first expansion chamber of the displacer cylinder 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 rear 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 piston rod 13 via the rollers 16 and the guide piston 12. Torso 9
Due to eccentricity, the four compression pistons 17 reciprocate within the cylinder 18 with a phase difference of about 90 degrees.

Further, the rotational torque of the crankshaft 4 is transmitted to the cam member 30 and converted into a 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.

On the other hand, the lubricating oil pump 70 directly connected to the reducer 5 is driven by the operation of the driving machine 6, and thereby,
The lubricating oil is supplied at a predetermined pressure to each oil supply section 71 (FIG. 2) of the crankcase 7, and is ejected from each nozzle hole 74 toward the body section 9. As a result, an oil film is formed on the outer peripheral surface of the body 9, and lubricating oil is constantly supplied to the contact surface between the body 9 and the roller 16.
The lubricating oil in the crank chamber 75 is led to the lubricating oil pump 70 side through the oil drain hole 76 and is circulated and supplied to the oil supply section 71 by the lubricating oil pump 70 again.

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 undergoes isothermal expansion 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, continuous 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 crankshaft 4 of this piston drive device 2 are provided.
A plurality of displacers 41 arranged concentrically with
Since the Stirling cycle refrigerator 1 is constructed by combining the displacer drive device 3 with a displacer drive device 3 having a 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, even if the cylinder diameter is increased, the axial dimension (vertical direction in FIG. 1) of the entire refrigerator does not increase. Furthermore, 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, the compression piston 17 and the guide piston 12 are connected coaxially, and the roller 1 of the guide piston 12 is
6 is in contact with the body 9, the side pressure applied from the body 9 to the guide piston 12, that is, the guide piston 1
The force applied in the direction perpendicular to the sliding direction of the cylinder 2 is weakened, and thereby the eccentric rotational movement of the body 9 can be smoothly converted into a reciprocating movement of the compression piston 17. Furthermore, since lubricating oil is supplied to the contact surface between the roller 16 and the body 9, the coefficient of friction is reduced, the frictional work can be reduced, and the wear and tear of parts due to friction is prevented to improve reliability. At the same time, the service life of parts can be maintained for a long time. Moreover, by reducing the frictional force, the driving torque of the crankshaft 4 can also be reduced, and the drive machine 6 can be made smaller.

Furthermore, in this embodiment, lubricating oil is supplied to the crank chamber 7.
Since the nozzle is injected within the crankcase 5, the entire crank chamber 75 becomes an oily atmosphere, and the effect of cooling the crankcase 7 is obtained. Furthermore, the frictional heat generated in the rollers 16 and bearings 15 of the guide piston 12 is dissipated into the lubricating oil that is sequentially supplied.
The cooling effect of the second bearing portion can be enhanced. Furthermore, the rear chamber 2 between the crank chamber 75 and the compression chamber 20
1 is always kept clean by the oil scrubbing ring 79 of the guide piston 12, so the refrigerant gas in the rear chamber 21 is not contaminated with oil, thereby preventing the refrigerant gas from being contaminated by oil. This prevents contamination of the inside of the heat exchanger 44 and the regenerator material, a decrease in heat transfer performance, and an increase in pressure loss, thereby improving refrigeration performance.

Furthermore, as a method of driving the displacer 41,
Since the cam member 30 is used, by appropriately changing the shape of the cam groove 32 of the cam member 30 within a range that does not interfere with the reciprocating motion of the drive body 33 and the rod 34, the most preferable displacer 41 from a thermodynamic point of view can be obtained. Reciprocating motion can be easily achieved.

Furthermore, the piston drive device 2 and the displacer drive device 3 are connected to the crankshaft 4 and the cam member 3.
0, the phase difference between the reciprocating movements of the compression piston 17 and the displacer 41 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 when the phase difference is 90 degrees. but,
In reality, it is 90 degrees, which is slightly off 90 degrees due to pressure loss and other factors.
The optimum value exists near the degree.

(Effects of the invention) As explained above, according to this invention, a displacer drive having 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 canceled out. Therefore, the bearing portion and the casing can be made lightweight and compact. Furthermore, even if the cylinder diameter is increased to increase the output, the device is prevented from becoming complicated or large.

Further, since the guide piston is interposed between the compression piston and the body and lubricating oil is supplied to the contact surface between the roller of the guide piston and the body, it is possible to prevent parts from being worn out due to friction. This increases reliability and maintains a long bearing life. Furthermore, by reducing the frictional force, the driving torque of the crankshaft can also be reduced, and it is possible to prevent the device from becoming larger. Furthermore, the interior of the back chamber of the compression piston is always kept clean by the oil scrubbing ring of the indoor piston, so the refrigerant inside the cylinder is not contaminated by lubricating oil, thereby preventing a drop in heat transfer performance. be able to.

[Brief explanation of drawings]

Fig. 1 is a vertical cross-sectional view of the refueled Stirling cycle refrigerator according to this invention, and Fig. 2 is a -
This is a cross section along the line. 1...Refueling type Stirling cycle refrigerator, 2
... Radial piston drive device, 3 ... Displacer drive device, 4 ... Crankshaft, 6 ... Drive machine, 9 ... Body, 12 ... Guide piston, 13
... Connecting rod, 16 ... Roller, 17 ... Compression piston, 30 ... Cam member, 32 ... Cam groove, 33
...Driver, 34... Rod, 38a, 38b...
...Regenerator, 41... Displacer, 21, 42
...Back chamber, 44...Heat exchanger, 46a, 46b
...Expansion chamber, 70...Lubricating oil supply device.

Claims (1)

[Scope of Claim for Utility Model Registration] The refrigerant compressed by the compression piston is sent to the rear chamber on one side of the displacer through a heat exchanger, passes through the regenerator in the displacer, and is then sent to the rear chamber on the other side of the displacer. In an oil-fed Stirling cycle refrigerator that lowers the temperature of refrigerant by flowing into an expansion chamber, a plurality of compression pistons and a guide piston connected coaxially with each compression piston are arranged radially, and the refrigerant is rotated by a drive machine. A radial piston drive device comprising a roller rotatably provided on the guide piston is brought into contact with the outer peripheral surface of the eccentric body of the crankshaft, and a plurality of 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. A displacer drive device in which a rod for reciprocating in the axial direction of a shaft is connected, and the shape of the cam member is set so that the phase of the corresponding displacer advances approximately 90 degrees with respect to each compression piston. A lubricating type Stirling cycle refrigerator, comprising: a lubricating oil supply device that supplies lubricating oil to a contact surface between the body and the roller.