Refrigerator

Disclosed is a refrigerator which comprises a plurality of reciprocating motion type expansion engines, a converter mechanism, a speed-up mechanism, and a energy converting mechanism. The engines and the three mechanisms are assembled solidly so that they are successively direct-coupled in a main direction substantially parallel to a direction in which pistons of the engines reciprocate. The converter mechanism converts reciprocating motion of the pistons into rotation by means of a cylindrical cam with an output shaft extending along the main direction, the speed-up mechanism increases the rotation speed of the cylindrical cam and rotates the output shaft at high speed, and the energy converting mechanism includes a generator section having a rotor direct-coupled to the output shaft, electric power generated at the generator section being consumed by an electric load located in a suitable position when the rotor is rotated at high speed.

This invention relates to a refrigerator provided with a refrigerating 
means including a plurality of reciprocating motion type expansion engines 
with reciprocating pistons extending substantially parallel and in the 
same direction with one another from their corresponding cylinders. 
Refrigerators of the aforesaid type have conventionally been used. In such 
prior art refrigerators, however, the operating speed of engines cannot be 
increased, so that only a low rotation speed can be obtained with use of a 
conventional motion converting means which converts one cycle of 
reciprocating motion of a piston into one revolution. Accordingly, a 
flywheel mounted on an output shaft of the motion converting means for 
maintaining the smoothness of the rotation cannot help being large-sized. 
Further, in the case of using an electro-magnetic brake or electric-power 
generator for the purpose of effectively consuming the mechanical energy 
issued from the engine, large-diameter brake disk or large-diameter rotor 
is required to be employed. This causes the device to become bulky. To 
remove these drawbacks, there was a proposition that a mechanism for 
increasing the speed of the rotation should be provided separately from 
the motion converting means and the mechanical energy consuming means, 
which was not, however, able to prevent the overall size of the 
refrigerator from being large. Meanwhile, as the study of superconduction 
is advanced, the range of application of the superconduction to the fields 
of spacecraft and aircraft is widened. Moreover, as a technique of 
magnetically elevating rapid trains has been developed, there has been an 
increasing demand for the development of compact refrigerators capable of 
being set in a narrow space. 
A first object of this invention is to provide a compact and light 
refrigerator free from the above-mentioned drawbacks of the prior art 
refrigerators. 
In order to attain the aforesaid first object, the refrigerator of the 
invention is provided with a converting mechanism having a first output 
shaft parallel to the extending direction of pistons or main direction and 
driven by the pistons, whereby reciprocating motion of the pistons is 
converted into rotation of the first output shaft, a speed-up mechanism 
having a second output shaft parallel to the main direction and driven by 
the first output shaft, whereby the second output shaft is rotated faster 
than the first output shaft, and an energy consuming mechanism composed of 
an energy converting mechanism having a rotation part mounted on the 
second output shaft and converting mechanical energy supplied from the 
second output shaft into electrical energy and a load means to consume the 
electrical energy obtained by way of the energy converting mechanism. 
According to the above-mentioned construction, reciprocating motion type 
expansion engines, the converting mechanism, the speed-up mechanism, and 
the energy converting mechanism are successively arranged substantially in 
a straight line along the main direction in which the pistons of the 
engines extend, enabling integral and compact assembly and hence 
contributing to miniaturization of the refrigerator. 
A second object of the invention is to provide a refrigerator including a 
converting mechanism which is relatively thin in the main direction and 
has a first output shaft extending parallel to the main direction. In 
order to attain such second object, a cylindrical cam having a second 
output shaft extending along the main direction and driven by the 
reciprocating motion of the pistons for rotation is used for the 
converting mechanism. By the use of such cylindrical cam, the converting 
mechanism may be improved in simplicity, compactness and smoothness of 
operation as compared with the conventional one employing a crank 
mechanism. 
A third object of the invention is to provide a refrigerator employing for 
the speed-up mechanism which has a second output shaft parallel to the 
main direction and is shortened in the main direction. In order to attain 
this object, the speed-up mechanism used for the refrigerator of the 
invention is of a planetary gear system, including a plurality of planet 
gears revolved by a first output shaft, a sun gear mounted on the second 
output shaft and engaging the planet gears, and a fixed internal gear 
engaging the planet gears. As capable of reduction in the dimension along 
the main direction, the speed-up mechanism of the aforementioned 
construction is a great convenience to the miniaturization of the main 
unit of refrigerator of the invention. 
Moreover, a fourth object of the invention is to provide a simple and light 
generator section with reduced thickness in the main direction for the 
energy converting mechanism included in the energy consuming mechanism. In 
order to attain this object, the energy converting mechanism is provided 
with a generator section composed of an exciting rotor mounted on the 
second output shaft of the speed-up mechanism and generating coils 
generating electric power by interaction with magnetic flux produced by 
the rotor. The generator section of the refrigerator of the invention 
having such construction can be formed into a thin body. 
A fifth object of the invention is to provide a refrigerator including a 
generator section including the exciting rotor which is simple in 
construction and hardly breaks down. In order to attain this object, a 
plurality of permanent magnets are used as a magnetic flux source for the 
rotor. The use of such permanent magnets enables us to remove slip ring 
which may otherwise be required for receiving electric current to the 
rotor from the outside, contributing to the simplified construction and 
compactness of the generator section. 
Further, a sixth object of the invention is to provide a refrigerator 
including a means for maintaining the operating speed of the expansion 
engines substantially at a fixed level. In order to attain this object, 
the refrigerator of the invention is provided with a control means to 
operate when the rotation speed of the converting mechanism or speed-up 
mechanism is changed from a predetermined level, thereby adjusting a 
current flow to the load means so as to keep the operating speed of the 
engines substantially constant. By the use of such control means, the 
operation of the expansion engines can be performed substantially at a 
fixed speed and stabilized. 
A seventh object of the invention is to provide a refrigerator in which the 
expansion engines, converter mechanism, speed-up mechanism, and the 
generator means are arranged substantially in a straight line along the 
main direction. In order to attain this object, the first output shaft of 
the converter mechanism and the speed-up mechanism are coaxially arranged 
substantially in a straight line. By doing this, the engines, converter 
mechanism, speed-up mechanism, and the generator means may be brought into 
alignment with one another. Such arrangement makes the main unit of 
refrigerator of the invention relatively elongated, simple and compact. 
Furthermore, an eighth object of the invention is to provide a refrigerator 
capable of achieving all of the first to seventh objects. In order to 
attain such eighth object, it is necessary only that the refrigerator of 
the invention be provided with all the object attaining means described in 
connection with the individual objects. Thus, there may be obtained 
effects or advantages corresponding to the first to seventh objects.

FIG. 1 is a block diagram of the refrigerator of this invention. As shown 
in this drawing, the refrigerator comprises a compressor 10, a main unit 
of refrigerator 12, a controller 14, a refrigerator chamber 16, and an 
electric load 46. The main unit 12 is composed of a refrigeration means or 
refrigerator section 18 and a power absorbing section 20. The refrigerator 
section 18 includes a substantially cylindrical vacuum tank 22, a heat 
exchanger group 24 consisting of five heat exchangers 24a, 24b, 24c, 24d 
and 24e disposed in the tank 22, two reciprocating motion type expansion 
engines (hereinafter referred to simply as engines) 30 and 32, and a 
Joule-Thomson valve 34. A high-pressure refrigerant delivered from the 
compressor 10 is introduced into the vacuum tank 22 and passed through the 
heat exchanger 24a to be cooled in some measure, and thereafter a part of 
such refrigerant is supplied to the engine 30. Supplied with the 
high-pressure refrigerant, the engine 30 is started to generate mechanical 
power caused by reciprocating motion of piston, and the refrigerant 
lowered in temperature and in pressure is returned to the compressor 10 
via the heat exchangers 24b and 24a. At this time, the high-pressure 
refrigerant passing through the heat exchangers 24a and 24b is cooled by 
the low-temperature, low-pressure refrigerant. The engine 32 is supplied 
with part of the high-pressure refrigerant which has passed through the 
heat exchanger 24c, thereby generating mechanical power in the same as the 
engine 30 and returning the refrigerant reduced in temperature and 
pressure to the compressor 10 successively through the heat exchangers 
24d, 24c, 24b and 24a. Thereupon, the high-pressure refrigerant passing 
through the heat exchangers 24a to 24d is cooled. The high-pressure 
refrigerant except the portion branched off to the engines 30 and 32 is 
reduced in temperature and pressure when it is passed through the 
Joule-Thomson valve 34, transmitted through a passage 36a to the 
prescribed refrigerator chamger 16 outside the vacuum tank 22, and then 
returned to the vacuum tank 22 through a passage 36b. The high-pressure 
refrigerant passing through the heat exchangers 24e to 24a is cooled by 
the refrigerant from the passage 36b together with the low-pressure, 
low-temperature refrigerant transmitted from the engines 30 and 32. 
The power absorbing section 20 includes a converter mechanism 38, a 
speed-up mechanism 40, an energy conversion mechanism or generator section 
42, and a sensor 44. The power absorbing section 20 and the refrigerator 
14 are constructed in a body to form the main unit 12. The converter 
mechanism 38 is driven by the reciprocating motion of the pistons of the 
engines 30 and 32 to convert the reciprocating motion into rotation. The 
speed-up mechanism 40 increases the speed of the rotation delivered from 
the mechanism 38, and drives the generator section 42 at high speed. 
Broken lines in FIG. 1 represent mechanical connection. Electric power 
generated at the generator section 42 is transmitted through the 
controller 14 to the load means or electric load 46, where it is consumed. 
Thus, the generator section 42, controller 14 and electric load 46 convert 
the mechanical energy, which is produced by the engines 30 and 32 and 
converted into energy of accelerated rotation, into electrical energy, and 
consume such energy. 
FIG. 2 is a partially sectional perspective view of the main refrigerator 
unit 12, chiefly showing members inside the vacuum tank 22 and the 
principal part of the converter mechanism 38 included in the power 
absorbing section 20. The vacuum tank 22, which is substantially 
cylindrical, contains therein the engines 30 and 32 respectively having 
cylinders 30b and 32b extending substantially parallel to the central axis 
X0X of the cylindrical body. Further, connecting rods 30c and 32c of 
pistons 30a and 32a (FIG. 3) used for the cylinders 30b and 32b extend 
substantially parallel to the central axis X--X to project from a top 
cover 22a of the vacuum tank 22, and are allowed to reciprocate. The four 
heat exchangers 24a, 24b, 24c, and 24d are arranged around the engines 30 
and 32, while the heat exchanger 24e is disposed near a base plate 22b of 
the vacuum tank 22 across a heat shielding plate 69 in contact with the 
heat exchanger 24a. The Joule-Thomson valve 34 is disposed below the 
engines 30 and 32. Thinner pipes 48 appearing on this side of the heat 
exchanger 24a constitute inlet and outlet for the high-pressure 
refrigerant passing through the heat exchanger 24a, while thicker pipes 50 
serve as inlet and outlet for the low-pressure refrigerant passing through 
the heat exchanger 24a. The same system is applied to the other heat 
exchangers including e.g. the heat exchanger 24d. An adjusting knob 52 
located above the top cover 22a is used for adjusting the opening of the 
Joule-Thomson valve 34 by means of a control rod 54 represented simply by 
a chain line. Numerals 10a and 10b designate passage connecting portions 
coupled respectively to the high-pressure refrigerant outlet and 
low-pressure refrigerant inlet of the compressor 10, while 16a and 16b 
denote passage connecting portions which deliver to the refrigerator 
chamber 16 and receive the low-temperature, low-pressure refrigerant 
passed through the Joule-Thomson valve 34, respectively. Since the heat 
exchangers 24a to 24e, engines 30 and 32, and refrigerant passages between 
the Joule-Thomson valve 34 and the passage connecting portions 10a, 10b, 
16a and 16b are clearly shown in FIG. 1, they are mostly omitted in FIG. 
2. 
Inside the power absorbing section 20 of FIG. 2, there is shown the 
principal part of the converter mechanism 38. Numeral 64 designates a 
cylindrical cam mounted on the same central axis X--X which converts 
reciprocating motion of the connecting rods 30c and 32c along the axis 
X--X, which is caused when the engines 30 and 32 are driven, into rotation 
about the axis X--X. Numeral 65 designates the output shaft of the 
cylindrical cam 64. Numeral 66 designates a coupling block which is 
attached to the tip end of the connecting rod 30c and transmits the 
reciprocating motion of the piston 30a (FIG. 3) to the cylindrical cam 
through a pin 68. The construction of this section is also shown in FIG. 
3. A coupling block to be attached to the tip end of the connecting rod 32 
of FIG. 2 is omitted for the simplicity of the drawing. Terminals 70 and 
72 protruding at the upper portion of the power absorbing section 20 are 
wiring terminals for supplying the controller 14 with electric power 
generated at the generator section 42 (FIGS. 1 and 3) included in the 
power absorbing section 20, while a terminal 74 is disposed inside the 
power absorbing section 20 and tends to detect the output-side rotation 
speed of the speed-up mechanism 40 and to supply the controller 14 with 
the output of the sensor 44 which delivers the result of the detection to 
the controller 14. Moreover, numerals 60 and 62 designate automatic valve 
units containing suction and exhaust valves that are used with the engines 
30 and 32, respectively. When the engines 30 and 32 are supplied with the 
high-pressure refrigerant, the automatic valve units 60 and 62 are 
actuated to cause the pistons 30a and 32a of the engines 30 and 32 to 
start reciprocation. 
FIG. 3 shows a sectional view of the power absorbing section 20 and a 
partial sectional view of the refrigerator section 18. The connecting rods 
30c and 32c extending respectively from the pistons 30a and 32a of the 
engines 30 and 32 project through the top cover 22a into the interior of 
an intermediate frame 76 attached to the top cover 22a, and reciprocate in 
the direction of the central axis X--X. The converter mechanism 38 as 
illustrated is composed of the cylindrical cam 64, and the pins 68 and 
ball bearings 68a attached to the tip ends of the connecting rods 30c and 
32c. Formed on and around the surface of the cylindrical cam 64 is a cam 
groove 64a which converts the reciprocating motion of the connecting rods 
30c and 32c into rotation of the cylindrical cam 64. Thus, when the 
engines 30 and 32 are operated, the cylindrical cam 64 is rotated by the 
action of the converter mechanism 38. 
The planetary gear type speed-up mechanism 40 is disposed at the right end 
portion of the intermediate frame 76. The mechanism 40 includes a sun gear 
82 mounted on a rotating shaft or output shaft 80 supported coaxially with 
the central axis X--X by an end frame 78 of magnetically soft material 
i.e. strong magnetism-material having high permeability on the right of 
the intermediate frame 76, an internal gear 84 at the right end portion of 
the intermediate frame 76, and three planet gears 86 engaging the gears 82 
and 84. The cylindrical cam 64 is borne by a ball bearing 88 attached to 
the top cover 22a and a ball bearing 90 attached to the left end of the 
rotating shaft 80. Numeral 92 designates a disk at the right end portion 
of the cylindrical cam 64, and the three planet gears are rotatably 
mounted on the disk 92 at angular intervals of 120.degree.. Accordingly, 
when the cylindrical cam 64 rotates, the three planet gears 86 orbit the 
sun gear 82 at the same speed with the rotation of the cylindrical cam 64. 
In this case, the internal gear 84 is fixedly attached to the intermediate 
frame 76, so that the sun gear 82 and hence the rotating shaft 80 rotate 
faster than the cylindrical cam 64. The ratio between the rotating speeds 
of the shaft 80 and the cylindrical cam 64 may be set to various values by 
diversely selecting the numbers of teeth of the sun gear 82, internal gear 
84, and planet gear 86. 
FIG. 4 shows the positional relationship between the internal gear 84, 
planet gear 86, and sun gear 82 as viewed from the left-hand side and 
taken at right angles to the central axis X--X of FIG. 3. The disk 92 
attached to the cylindrical cam 64 and sustaining the planet gears 86 is 
represented by a chain line. 
The end frame 78 is fitted with the generator section 42. The generator 
section 42 includes a thick discoid rotating part or rotor 96 keyed to the 
shaft 80 inside a chanber 94 defined in the end frame 78, and a plurality 
of generating coils 98 fitted in grooves 98a formed in the end frame 78. 
The rotor 96 is composed of an annular permanent magnet 100 so magnetized 
as to have a plurality of magnetic poles, a magnetic holder 104 of 
nonmagnetic material to hold the permanent magnet 100 in its annular 
recess 102, and a cover 106 of magnetically soft material i.e. strong 
magnetism-material having high permeability attached to the magnet holder 
102 in close contact with the permanent magnet 100 so as to retain the 
magnet 100 in the recess 102 and serving as a backplate for the magnet 100 
to provide a magnetic path. The rotor 96 faces a wall surface of the 
chamber 94 fitted with the generating coils 98 across an air gap 108. 
FIG. 5 is a view of the rotor 96 cleared of the cover 106 as taken from the 
right of FIG. 3, showing the polarity distribution of the magnetic poles 
formed in the permanent magnet 100. Each shown polarity is one on this 
side of the drawing, and magnetic poles on the other side have opposite 
polarity. 
FIG. 6 shows the arrangement of the generating coils 98 as viewed from the 
right of FIG. 3. 
Magnetic flux produced from the permanent magnet 100 passes through a 
portion of the end frame 78 facing the rotor 96, that is, the region where 
the generating coils 98 are arranged. Accordingly, when the engines 30 and 
32 are started to rotate the rotor 96 at high speed, the magnetic flux 
from the permanent magnet 100 moves across the coil sides of the 
generating coils 98, so that AC voltages are induced at the respective 
generating coils 98. These voltages are added together by suitable 
connection means and led through the terminals 70 and 72 to the controller 
14. 
FIG. 7 is a block diagram for illustrating the construction and operation 
of the controller 14. Electric power delivered from the generating section 
42 is sent to a rectifier 120 in the controller 14, where it is converted 
into DC power. The DC power is supplied to the external electric load 46 
through a load adjuster 122 and a constant-voltage regulator 124. The load 
adjuster 122 controls electric power supplied to the electric load 46, 
assisting the engines 30 and 32 in operating at a predetermined speed. 
The load adjuster 122 operates in accordance with the detection value from 
the sensor 44 to detect the rotation speed of the shaft 80 (FIG. 3) in the 
power absorbing section 20. A detection signal delivered from the sensor 
44, which is a frequency signal in proportion to the rotation speed of the 
shaft 80, is converted into a voltage proportional to the rotation speed 
by an F/V converter 126. This voltage is supplied to a deviation amplifier 
130, together with a set voltage determined by a rotation speed setter 
128. The output of the deviation amplifier 130 is a voltage which is 
proportional to the difference between the set voltage and the output 
voltage of the converter 126. The obtained output voltage is amplified by 
an amplifier 132, and then supplied to the load adjuster 122. The power 
transmitted to the regulator 124 is controlled by a voltage signal 
supplied from the amplifier 132 as follows. Namely, when the rotation 
speed of the shaft 80 is higher than a value corresponding to the set 
value of the first setter or rotation speed setter 128, the control signal 
delivered from the amplifier 132 acts on the load adjuster 122 so as to 
increase the power supplied to the electric load 46. When the rotation 
speed of the shaft 80 is lower than the set value, on the other hand, the 
signal so functions as to decrease the power supplied to the electric load 
46. Accordingly, mechanical load applied to the shaft 80 through the 
generator section 42 is varied by changing the rotation speed of the shaft 
80 as compared with the predetermined value. Thus, the rotation speed of 
the shaft 80 may be maintained substantially at the value determined by 
the rotation speed setter 128. 
The output of the converter 126 is transmitted to a comparator 136 together 
with the set value for the shaft 80 delivered from a second setter or 
maximum rotation speed setter 134. When the rotation speed of the shaft 80 
becomes higher than the value corresponding to the set value, an 
over-rotation alarm circuit 138 is actuated, and a danger signal is given 
from an alarm 140. 
Although a typical refrigerator according to this invention has been 
described herein, various modifications may be effected. For example, 
instead of using the cylindrical cam for the converter mechanism 38, there 
may be employed a converting mechanism which utilizes the well-known swash 
plate system. Moreover, the number of engines, which is two for the 
above-mentioned embodiment, may be increased as required. 
In any case, according to the refrigerator of the invention, the 
reciprocating motion of pistons obtained from a plurality of reciprocating 
motion type engines is converted into rotation and the rotation is 
accelerated to drive a load member on the engines, so that the load 
member, such as e.g. the generator section 42 for the above-mentioned 
embodiment, may be made compact. Since electric power generated by the 
generator section is consumed by the electric load 46 outside the main 
refrigerator unit 12, energy consumed within the main unit 12 is extremely 
little, making it easy to restrain the temperature of the main unit 12 
from rising. 
Furthermore, the main refrigerator unit 12 may be formed into a 
substantially cylindrical, compact body by employing for the speed-up 
mechanism 40 such mechanism that the input and output shafts are on the 
same axis like the planetary gear type mechanism of the aforementioned 
embodiment, as well as the cylindrical cam or swash plate system for the 
converter mechanism 38, and also by locating the generator section 42 
coaxially with the speed-up mechanism 40. Such compaction or reduction in 
size enables the refrigerator of the invention to be placed in a train 
which utilizes magnetic elevation effect, and also to be set in any place 
that is limited in floor space.