Patent Publication Number: US-6209328-B1

Title: Oil-free compressor-integrated pulse tube refrigerator

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a pulse tube refrigerator driven by an oil free type compressor, and in particular to a compressor integrated pulse tube refrigerator of an oil free type which is capable of maintaining an accurate gap between an inner surface of a cylinder and an outer surface of a piston so that a gas is not leaked through the gap to the outside in a state that the piston does not contact with an inner surface of the cylinder when the piston reciprocates within the cylinder. 
     2. Description of the Background Art 
     Generally, as a ultra low temperature refrigerator which is used for cooling a small size electronic component and a super-conductive material, a thermal reproducing type refrigerator such as a Stirling refrigerator, a GM refrigerator, etc. is used. 
     The resistance of most typical electronic components are decreased at a low temperature for thereby increasing an operational efficiency of the components, and the processing speed of a CPU(Central Processing Unit) used for a computer is increased. 
     In addition, as the super-conductive product is intensively studied, the need for a low temperature price ultra low refrigerator which is capable of satisfying the cooling conditions of the small size components is gradually increased. 
     In order to increase the reliability of the above-described refrigerator, the operation speed is decreased, or a lubricating operation is enhanced for preventing an abrasion between the friction portions during a pumping operation of a working gas, or the characteristic of a sealant is improved. In addition, the number of the operational portions is decreased. 
     Recently, as a ultra low temperature refrigerator which has a high reliable operation and is capable of implementing a high speed operation and does not need an additional lubricating operation and a maintenance for a long time, an oil free type compressor pulse tube refrigerator is disclosed. 
     The above-described oil free type compressor pulse tube refrigerator is directed to implementing a ultra low temperature refrigerating operation at an open side of the tube using a principle that when varying a pressure by periodically injecting a gas having a certain temperature into a one side-blocked tube, a large temperature variation is obtained at a portion in which there is a turbulent flow of the gas. Namely, the oil free type compressor pulse tube refrigerator is a refrigerator having a low average pressure and pressure ratio and a low refrigerating capacity. In the oil free type compressor pulse tube refrigerator, the pulse tube refrigerator includes one movement unit of a compressor compared to the conventional Stirling refrigerator having two movement units of a piston and displacer. 
     As a pulse tube refrigerator, there are a basic type pulse tube refrigerator, a resonance type pulse tube refrigerator having an acoustic driving unit, a hole type pulse tube refrigerator fabricated by installing an orifice, which generates a phase difference of a pressure pulse and a mas flow rate, and a storing container at the basic type pulse tube refrigerator, and an inertia tube type pulse tube refrigerator using an inertance tube(long neck tube) instead of the orifice. Among the above-described refrigerators, the basic type pulse tube refrigerator, the hole type pulse tube refrigerator and the inertia tube type pulse tube refrigerator will be explained. 
     First, as shown in FIG. 1, the basic type pulse tube refrigerator includes a driving unit M, a hollow pulse tube  1  having a warm end  1   a  and a cold end  1   b  for introducing a working gas pumped by the driving unit M for thereby compressing and expanding the gas therein, and a reproducing unit  2  connected between the driving unit M and the pulse tube  1  for maintaining a certain temperature of the working gas which contains a sensible heat due to a temperature difference based on the compressing and expanding operations of the working gas. 
     In the drawing, reference numerals  2   a  and  2   b  represent the connection tubes. 
     The operation of the basic type pulse tube refrigerator will be explained with reference to the accompanying drawings. 
     First, when the driving unit M pushes the working gas into the interior of the reproducing unit  2 , the thusly pushed high temperature and pressure working gas having a sensible heat flows through the reproducing unit  2  and is flown into the pulse tube  1 . The working gas in the pulse tube  1  is flown toward the blocked side and then is more compressed. At the warm end portion  1  a, a heat is radiated based on a heat transfer operation at the tube wall. 
     On the contrary, when the driving unit M sucks the working gas, the gas introduced into the interior of the pulse tube  1  is discharged, and the working gas in the pulse tube  1  is expanded, the heat is absorbed at the cold end  1   b  by a heat transfer at the tube wall. The above-described operation is repeatedly performed, so that it is possible to obtain a ultra low temperature(about −20° C.) at the cold end. At this time, the working gas discharged from the pulse tube  1  absorbs the heat stored in the reproducing unit  2  and is heated by a certain temperature and is introduced into the driving unit M. 
     The hole type pulse tube refrigerator will be explained with reference to the accompanying drawing. 
     First, as shown in FIG. 2, the hole type pulse refrigerator includes a driving unit M, a pulse tube  3  having a warm end portion  3   a  at which a gas is compressed and a cold end  3   b  at which a gas is expanded, as the working gas pumped by the driving unit M is inwardly introduced for thereby implementing a certain mass flow rate of the working gas, an orifice  4  connected with the warm end portion  3   a  of the pulse tube  3  for generating a certain phase difference based on the mass flow rate of the flowing working gas and the pressure pulse operation, a storing container  5  connected with the orifice  4  and holding the working gas therein for a certain time, and a reproducing unit  6  connected between the cold end  3   b  and the driving unit M for storing a sensible heat of the working gas pumped toward the pulse tube  3  and supplying the stored heat when the working gas flows from the pulse tube  3  to the driving unit M. 
     In the drawing, reference numerals  4   a ,  6   a  and  6   b  represent the connection tube. 
     The operation of the hole type pulse tube refrigerator is similar with the basic type pulse tube refrigerator except for the following difference. Namely, in the basic type pulse tube refrigerator, the heat is radiated from the working gas via the tube wall of the pulse tube  1 . In the hole type pulse tube refrigerator, the working gas flows through the orifice  4  and increases the phase difference between the mass flow rate and the pressure pulse operation based on an adiabatic expansion for thereby obtaining a higher cooling capability. 
     Namely, in the hole type pulse tube refrigerator, when the working gas is supplied by the driving unit M and flows via the reproducing unit  6  and is introduced into the pulse tube  3 , the working gas filled in the pulse tube  3  is adiabatically compressed, so that the temperature of the working gas is increased and is penetrated into the orifice  4 , whereby the working gas is expanded by the orifice  4  and is filled in the storing container  5 . 
     In addition, in the basic pulse tube refrigerator, the working gas is re-heated by receiving the heat from the tube wall, and in the hole type pulse refrigerator, the working gas is heated while the working gas flows the orifice  4  and is adiabatically compressed in the pulse tube  3 . 
     When the working gas is sucked by the driving unit M, the working gas is adiabatically expanded due to a mass flow rate difference between the working gas flown from the pulse tube  3  and the working gas introduced into the pulse tube  3  via the orifice  4  when the working gas is flown from the pulse tube  3  to the reproducing unit  6 , so that the temperature of the working gas is decreased. 
     The working gas in the pulse tube  3  is compressed by the working gas which is continuously introduced via the orifice  4 , so that a ultra low temperature refrigerating effect of the pulse tube is obtained by the above-described processes. 
     In addition, in the inertia tube type pulse tube refrigerator which uses a lengthy tube having a small diameter instead of the orifice, it is possible to enhance the performance by increasing the variation of the phase difference between the mass flow rate and the pressure pulse operation. 
     The above-described pulse tube refrigerator and the inertia tube type pulse tube refrigerator generate a higher refrigerating capability based on the phase difference between the mass flow rate and the pressure pulse differently from the basic type refrigerator. The orifice and inertia tube are called as a phase controller(or a phase device or a phase developer). The hole type and inertia type pulse refrigerator(hereinafter called as a “Pulse tube refrigerator”) will be explained. 
     As shown in FIG. 3, the conventional pulse tube refrigerator includes a driving unit  10  for generating a reciprocating flow of the working gas, a refrigerating unit  20  for having a ultra low temperature portion based on a thermal mechanics cycling operation of the working gas which reciprocates in the tube by the driving unit  10 , and a valve selectively communicating the driving unit  10  and the refrigerating unit  20 . 
     The structures of the driving unit  10  and the refrigerating unit  20  will be explained in detail. 
     The driving unit  10  includes a compressor  11  used for a common refrigerator using a lubricating oil, a low pressure container  12  installed at an inlet of the compressor  11  for storing a low pressure suction gas, a high pressure container  13  installed at an outlet of the compressor  11  for storing a high pressure exhausting gas, and an oil separating unit  14  installed between the high pressure container  13  and the outlet of the compressor  11  for removing an oil contained in the working gas and supplying the working gas to the compressor  11 . 
     In the drawings, reference numerals  11   a ,  11   b ,  11   c ,  12   a ,  13   a , and  14   a  represent the connection tubes. 
     The refrigerating unit  20  includes a pulse tube  21  having a compression portion  21   a  at which a compression is performed for thereby generating a heat and an expansion portion  21   b  at which an expansion is performed for thereby absorbing a heat as the working gas is mass-flown and a compression and expansion are performed at both ends of the same by the working gas pumped by the driving unit  10 , an orifice  22  connected with the compression unit  21   a  of the pulse tube  21  for generating a phase difference between the mass flow rate of the working gas and the pressure pulse and implementing a thermal balance state, a storing container  23  connected with the orifice  22  for temporarily storing the working gas, a reproducing unit  24  connected between the expansion unit  21   b  of the pulse tube  21  and the driving unit  10  for compensating the temperature of the working gas returning from the pulse tube  21  to the driving unit, and a pre-cooling unit  25  connected between the reproducing unit  24  and the driving unit  10  for pre-cooling a high temperature and pressure working gas pumped from the driving unit  10 . 
     The valve  30  is a rotary valve for repeatedly communicating the low pressure container  12  and the pre-cooling unit  25  or the high pressure container  13  and the pre-cooler  25  at a certain time interval and is installed between the low pressure container  12  and the high pressure container  13  of the driving unit  10  and the pre-cooling unit  25  of the refrigerating unit  20 . 
     In the drawings, reference numeral  15  represents a driving unit casing, and  30   a  and  22   a  represent the connection tubes. 
     The operation of the conventional pulse tube refrigerator will be explained with reference to the accompanying drawings. 
     First, a low temperature and pressure working gas charged in the low pressure container  12  is compressed and changed to a high temperature and pressure working gas by the compressor  11  and passes trough the oil separating unit  14  and is stored in the high pressure container  13 . 
     At this time, the oil separating unit  14  separates the oil contained in the working gas and outputs the separated oil to the compressor  11  and outputs the gas to the high pressure container  13 . 
     First, the valve  30  communicates the high pressure container  13  and the refrigerating unit  20 , and a high pressure working gas is cooled by the pre-cooling unit  25  and the reproducing unit  24  and is flown into the pulse tube  21 . The working gas introduced into the pulse tube  21  pushes the working gas filled in the pulse tube  21  toward the orifice  22 . At this time, the working gas filled in the pulse tube  21  is in a thermal balance state with respect to the tube wall and is moved toward the orifice  22 , so that the working gas is adiabatically compressed, and the temperature of the same is increased. 
     As the valve  30  is closed, the pressure in the pulse tube  21  is maintained in a high pressure state, and the working gas in the pulse tube  21  is flown toward the lower pressure side storing container  23  via the orifice  22 . During the above-described operation, the working gas is adiabatically expanded for thereby radiating the heat to the outside. The working gas in the pulse tube  21  becomes a thermal balance state at a temperature lower than at the initial state of the operation. 
     Thereafter, when the valve  30  communicates the low pressure container  13  and the refrigerating unit  10 , the low temperature working gas filled in the pulse tube  21  is moved toward the low pressure container  12 . The working gas moved toward the storing container  23  is moved again toward the pulse tube  21 . At this time, the mass flow rate of the working gas which is flown from the pulse tube  21  via the reproducing unit  24  is greater than the mass flow rate of the working gas introduced into the pulse tube  21  via the orifice  22 . Therefore, the working gas in the expansion unit  21   b  of the pulse tube  21  is rapidly adiabatically expanded, and the temperature of the same becomes a ultra low temperature. 
     Next, the valve  30  is closed. When the pressure in the pulse tube  321  is low, the working gas is flown into the pulse tube  21  from the storing container  23  to the orifice  22 , so that the working gas in the pulse tube  21  is compressed, and the temperature of the same is increased up to the temperature before the driving operation. The above-described operation forms one cycle. 
     The working gas introduced into the low pressure container  12  via the reproducing unit  24  and the pre-cooling unit  25  is flown into the compressor  11  and is compressed therein. The thusly compressed working gas is filled into the high pressure container  13 . When the valve  30  is opened, the working gas is flown again into the pulse tube  21 . The above-described cycle is repeatedly performed. The temperature of the expansion unit  21   b  of the pulse tube  21  is decreased to about −200° C. 
     However, in the conventional pulse tube refrigerator, the structure of the refrigerator is simple. However, the driving unit includes a compressor, high/low pressure containers, an oil separating unit, etc. Therefore, the size of the system is too large. Since the elements such as the compressor, the high and low pressure container, the oil separating unit, etc. are independently assembled for forming one driving unit, the number of the assembling processes is increased, and the assembling time is extended. 
     In addition, due to a limitation with respect to the operation speed of the valve which selectively connects the driving unit and the refrigerating unit, it is impossible to properly supply a working gas to the refrigerating unit. The working gas which passes through the valve is adiabatically expanded, so that the efficiency of the refrigerator is decreased. 
     SUMMARY OF THE INVENTION 
     Accordingly, it is an object of the present invention to provide a compressor integrated pulse tube refrigerator of an oil free type which is capable of implementing a stable reciprocating movement between a cylinder and a piston in a state that an outer surface of the piston does not contact with an inner surface of the cylinder. 
     It is another object of the present invention to provide a compressor integrated pulse tube refrigerator of an oil free type which is capable of implementing an easier fabrication and assembly of a support member for a reciprocating movement of a piston. 
     It is another object of the present invention to provide a compressor integrated pulse tube refrigerator of an oil free type which makes it possible to increase a mass flow rate of a working gas and decrease a gas expansion loss before the gas is flown into the refrigerating unit by removing a valve disposed between a driving unit and a refrigerating unit and directly connecting the driving unit and the refrigerating unit for thus directly transferring a gas compression and expansion effect of a compressing unit to a refrigerating unit, so that it is possible to increase an efficiency of the refrigerator. 
     It is another object of the present invention to provide a compressor integrated pulse tube refrigerator of an oil free type which makes it possible to fabricate a compact product by integrally forming a compression unit and a refrigerating unit, decrease a fabrication cost and obtaining a high efficiency. 
     It is another object of the present invention to provide a compressor integrated pulse tube refrigerator of an oil free type which makes it possible to prevent a damage of the system by a fatigue generated as a support member repeatedly reciprocates for obtaining a resonance of a driving motor and enhancing a reliability of a refrigerator. 
     It is another object of the present invention to provide a compressor integrated pulse tube refrigerator of an oil free type which is capable of minimizing a contact area of a sealed casing and a plate spring. 
     To achieve the above objects, there is provided a compressor integrated pulse tube refrigerator of an oil free type according to a first embodiment of the present invention which comprises a driving unit including a sealed casing having a cylinder disposed at an upper center portion of the same and a working gas filled therein, a linear motor installed in the interior of the sealed casing for generating a driving force, a driving shaft which is engaged to a rotor of the linear motor and linearly reciprocates, a piston connected with the driving shaft and inserted in the cylinder and reciprocating together with the driving shaft for thereby pumping a working gas, and a plurality of elastic guide support members provided in the interior of the sealed casing; and a refrigerating unit. 
     To achieve the above objects, there is provided a compressor integrated tube refrigerator of an oil free type according to a second embodiment of the present invention which comprises a driving unit including a sealed casing having a cylinder therein at an upper center portion wherein a working gas is filled in the sealed casing, a linear motor installed in the interior of the sealed casing for generating a driving force, a piston inserted in the cylinder and having a head portion and a shaft portion having a diameter smaller than the head portion and moving together with the rotor engaged with a nut shape engaging member in a state that the shaft portion is engaged with the rotor of the linear motor, and a plurality of elastic guide support members engaged in the interior of the sealed casing for generating a resonant movement of the piston; and a refrigerating unit. 
     Additional advantages, objects and features of the invention will become more apparent from the description which follows. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein: 
     FIG. 1 is a schematic view illustrating a conventional basic type pulse tube refrigerator; 
     FIG. 2 is a schematic view illustrating a conventional hole type pulse tube refrigerator; 
     FIG. 3 is a view illustrating a pipe mechanism for a conventional hole type pulse tube refrigerator; 
     FIG. 4 is a vertical cross-sectional view illustrating the entire construction of a compressor integrated pulse tube refrigerator of an oil free type according to a first embodiment of the present invention; 
     FIG. 5 is a vertical cross-sectional view illustrating a driving unit for a compressor integrated pulse tube refrigerator of an oil free type according to a first embodiment of the present invention; 
     FIG. 6 is a cross-sectional view taken along line VI—VI of FIG. 5; 
     FIG. 7 is a vertical cross-sectional view illustrating an example of a compressor integrated pulse tube refrigerator of an oil free type according to a modification first embodiment of the present invention; 
     FIG. 8 is a vertical cross-sectional view illustrating a compressor integrated pulse tube refrigerator of an oil free type according to a second embodiment of the present invention; 
     FIG. 9 is a view illustrating the portion IX of FIG. 8; 
     FIG. 10 is a view illustrating a cross-sectional view taken along line X—X of FIG. 10; 
     FIG. 11A is a view illustrating the portion XI of FIG. 10; 
     FIG. 11B is a detailed view illustrating the portion XI of FIG. 10; 
     FIG. 12 is a vertical cross-sectional view illustrating a compressor integrated pulse tube refrigerator of an oil free type according to a third embodiment of the present invention; 
     FIG. 13 is an enlarged vertical cross-sectional view illustrating a driving unit for a compressor integrated pulse tube refrigerator of an oil free type according to a third embodiment of the present invention; 
     FIG. 14 is a cross-sectional view taken along line XIV—XIV of FIG. 13; 
     FIG. 15 is a cross-sectional view taken along line XV—XV of FIG. 13; 
     FIG. 16 is a vertical cross-sectional view illustrating a compressor integrated pulse tube refrigerator of an oil free type according to a fourth embodiment of the present invention; 
     FIG. 17 is an enlarged vertical cross-sectional view illustrating a driving unit for a compressor integrated pulse tube refrigerator of an oil free type according a fourth embodiment of the present invention; 
     FIG. 18 is a cross-sectional view taken along line XVIII—XVIII of FIG. 17; 
     FIG. 19 is a vertical cross-sectional view illustrating a compressor integrated pulse tube refrigerator of an oil free type according to a fifth embodiment of the present invention; 
     FIG. 20 is an enlarged vertical cross-sectional view illustrating a driving unit for a compressor integrated pulse tube refrigerator of an oil free type according to a fifth embodiment of the present invention; 
     FIG. 21 is a cross-sectional view taken along line XXI—XXI of FIG. 20; 
     FIG. 22 is a vertical cross-sectional view illustrating a compressor integrated pulse tube refrigerator of an oil free type according to a sixth embodiment of the present invention; 
     FIG. 23 is an enlarged vertical cross-sectional view illustrating a driving unit for a compressor integrated pulse tube refrigerator of an oil free type according to a sixth embodiment of the present invention; 
     FIG. 24 is a cross-sectional view taken along line XXIV—XXIV of FIG. 23; 
     FIG. 25 is a horizontal cross-sectional view illustrating the portion XXV of FIG. 23; 
     FIG. 26 is a cross-sectional view illustrating a compressor integrated pulse tube refrigerator of an oil free type according to a seventh embodiment of the present invention; 
     FIG. 27 is a vertical cross-sectional view illustrating a compressor integrated pulse tube refrigerator of an oil free type according to an eighth embodiment of the present invention; 
     FIG. 28 is an enlarged view illustrating a state that a piston is inserted into a cylinder of FIG. 27; 
     FIG. 29 is a front view illustrating an inner surface of a linear bearing of FIG. 27; 
     FIG. 30 is a vertical cross-sectional view illustrating an example of a compressor integrated pulse tube refrigerator of an oil free type according to an eighth embodiment of the present invention; 
     FIG. 31A is a front cross-sectional view illustrating a plate spring mounting structure used for a compressor integrated pulse tube refrigerator of an oil free type according to the present invention; 
     FIG. 31B is a plan cross-sectional view of FIG. 31A; 
     FIG. 32A is a front cross-sectional view illustrating a support member of a plate spring mounting structure used for a compressor integrated pulse tube refrigerator of an oil free type according to the present invention; 
     FIG. 32B is a plan view illustrating a support member of a plate spring mounting structure used for a compressor integrated pulse tube refrigerator of an oil free type according to the present invention; 
     FIG. 33A is a front cross-sectional view illustrating another example of a plate spring mounting structure used for a compressor integrated pulse tube refrigerator of an oil free type according to the present invention; 
     FIG. 33B is an enlarged view of a ring; and 
     FIG. 33C is a plan cross-sectional view of FIG.  33 A. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The embodiments of the compressor integrated pulse tube refrigerator of an oil free type according to the present invention will be explained with reference to the accompanying drawings. 
     The compressor integrated pulse tube refrigerator of an oil free type according to each embodiment of the present invention is basically directed to pumping a working gas as a piston engaged to a rotor of a linear motor(hereinafter called as a driving motor) reciprocates within the interior of a cylinder without a friction between an outer surface of the piston and an inner surface of the cylinder without using an additional lubricating oil. 
     As shown in FIG. 4, the compressor integrated pulse tube refrigerator according to a first embodiment of the present invention includes a driving unit  100  for generating a reciprocating movement of a working gas, and a refrigerating unit  200  having a ultra low temperature portion as the working gas pumped by the driving unit  100  reciprocates in the interior of the system. 
     The driving unit  100  includes a hollow cylindrical sealed casing  110  in which a cylinder  110   a  is formed at an upper center portion of the same, and a working gas is filled therein, a driving motor  120  disposed in the interior of the sealed casing  110  for generating a driving force, a driving shaft  130  engaged to the rotor  122  (described later) of the driving motor  120  and reciprocating together with the rotor, a piston  140  engaged to one end of the driving shaft  130  and inserted in the cylinder  110   a  for pumping the working gas as the same reciprocates together with the driving shaft  130 , and a plurality of support members engaged to the driving shaft in the interior of the sealed casing  110  for receiving a reciprocating movement of the rotor  122  of the driving motor  120 , storing the reciprocating movement as an elastic energy, converting the thusly stored elastic energy into a straight movement, generating a resonant movement of the piston  140 , enabling the piston to repeatedly reciprocate, and guiding a reciprocating movement of the piston  140  which is moved by a reciprocating movement of the rotor  122  of the driving motor  120  at a certain space from the inner surface of the cylinder  110   a.    
     The support members according to the first embodiment of the present invention are formed of circular plate springs which are formed in a spiral form and each includes a first elastic guide support member  151  and a second elastic guide support member  152  which operate in the axial direction for limiting a certain inclination in the radial direction. 
     The construction of the elements according to the first embodiment of the present invention will be explained. 
     The sealed casing  110  includes an upper frame  111  in which the cylinder  110   a  is formed so that the piston  140  reciprocates in the cylinder  110   a , an intermediate frame  112  which is engaged with the lower surface of the upper frame  111  for thereby being concentrically formed with the upper frame  111  and has an inner surface engaged with an entire edge portion of the first elastic guide support member  151  engaged with the upper portion of the driving shaft  130  and in which the driving motor  120  is engaged, a lower frame  113  which is engaged with a lower surface of the intermediate frame  112  for thereby being concentrically formed with the intermediate frame  112  and is engaged with an entire edge portion of the second elastic guide support member  152  engaged with the lower portion of the driving shaft  130 , and a sealed shell  114  surrounding the intermediate frame  112  and the lower frame  113  and having its upper end portion which is sealingly engaged with the lower surface of the upper frame  111  for thereby preventing the working gas from being leaked from the sealed casing  110 . 
     The structure of the intermediate frame  112  will be explained in more detail. 
     In the intermediate frame  112 , a circular shape motor support portion  112   a  is inwardly protruded for mounting the driving motor  120  at the intermediate portion of the inner surface, and a plurality of first elastic guide support member engaging portions  112   b  are inwardly protruded at the same height, on which the edge portions of the first elastic guide support member  151  is positioned and engaged at the upper portion of the motor support portion  112   a.    
     At this time, the inner diameter of each of the first elastic guide support member engaging portions is smaller than the outer diameter of the driving motor for increasing the straight movement and the concentric degree which may be decreased when the diameter of the first elastic guide support member  151  is relatively great. 
     In the lower frame  113 , a plurality of second elastic guide support member engaging portions  113   a  which are inwardly protruded for engaging the second elastic guide support member  152  at the inner surface are formed at the same height in the same shape as the first elastic guide support member engaging portion  112   b  of the intermediate frame  112 . 
     The inner diameter of the second elastic guide support member engaging portion  113   a  is preferably smaller than the outer diameter of the driving motor  120  for the same reason as the first elastic guide support member engaging portion  112   b  formed at the intermediate frame  112 . 
     As shown in FIG. 6, driving shaft engaging holes  151   a  and  152   a  formed at the center portion of the first elastic guide support member  151  and the second elastic guide support member  152  are formed concentrically with the cylinder  110   a  of the upper frame  111  for maintaining a straight reciprocating movement of the piston  140   a.    
     The structure of the driving motor  120  will be explained in detail. 
     The driving motor  120  includes a known linear motor which is formed of inner and outer laminations  121   a  and  121   b  formed of a plurality of stacked steel plates, a stator  121  formed of a plurality of coils  121   c  wound onto the outer lamination  121   b , and a rotor  122  disposed between the inner and outer laminations  121   a  and  121   b  and engaged with the driving shaft  130  and having a magnet  122   b  formed opposite the coil  121   c . The outer lamination  121   b  is engaged to the intermediate frame  112  in the interior of the sealed casing  110 , and the inner lamination  121   a  is integrally engaged with the outer lamination  121   b  by an additional connection ring  123 . 
     In addition, the driving shaft  130  passes through the upper center portion of the cylindrical rotor  122  having its opened lower surface and is integrally engaged with the rotator  122 . The upper end of the driving shaft  130  passes through the center portion of the first elastic guide support member  151  and is integrally inserted into the piston  140 . The lower end of the same passes through the center portion of the second elastic guide support member  152  and is fixedly inserted into the fixing member  160 . 
     Here, in order to implement a resonance movement and straight movement of the driving shaft  130 , the driving shaft  130 , the first elastic guide support member  151 , and the second elastic guide support member  152  are concentrically installed. 
     As shown in FIG. 5, an upper support shoulder portion  130   a  is formed on the upper portion of the driving shaft  130  and contacts with the center portion of the lower surface of the first elastic guide support member  151  at a certain outer portion of the driving shaft  130  which is positioned at a lower portion of the piston  140 . A lower support shoulder portion  130   b  is formed at a lower portion of the driving shaft  130  and contacts with the center portion of the upper surface of the second elastic guide support member  152  at a certain outer portion of the driving shaft  130  positioned at the upper portion of the fixing member  160 . 
     As shown in FIG. 4, the refrigerating unit  200  includes a pulse tube  210  includes a pulse tube  210  having a compression portion  211  (warm portion) at which a compression is performed, and an expanding portion  212 (cold end) at which an expansion is performed wherein the working gas in the refrigerating unit  200  is mass-flown by the working gas pumped by the cylinder  110   a  of the sealed casing  110  at above-described both ends for thereby externally absorbing the heat, an orifice  220  connected with the compression portion  211  of the pulse tube  210  for generating a phase difference between the mass flow rate of the flowing working gas and the pressure pulse for thereby implementing a thermal balance, a storing container  230  connected with the orifice  220  and having the working gas therein for a certain time, a reproducing unit  240  connected between the expansion unit  210   b  of the pulse tube  210  and the cylinder  110   a  of the cylinder  110   a  for storing a sensible heat of the working gas pumped to the pulse tube  210  and supplying the stored heat when the working gas is returned to the cylinder  110   a  of the driving unit  100  in the pulse tube  210 , and a pre-cooling unit  250  connected between the reproducing unit  240  and the cylinder  110   a  of the driving unit  100  for pre-cooling the high temperature and pressure working gas. 
     In the first embodiment of the present invention, the pre-cooling unit  250  of the refrigerating unit  200  is mounted at the center portion of the upper surface of the cylinder  110   a  of the upper frame  111 . In an example of the first embodiment of the present invention, as shown in FIG. 7, the pre-cooling unit  250  of the refrigerating unit  200  may be installed at a portion spaced apart from the cylinder using an additional connection tube  260 , so that the heat generated at the cylinder  110   a  is not directly transferred to the pre-cooling unit  250 , namely, is radiated to the outside. 
     The assembling sequence of the compressor integrated pulse refrigerator of an oil free type according to a first embodiment of the present invention will be explained as follows. 
     First, an outer lamination  121   b  of the driving motor  120  is engaged to the motor support portion  112   a  of the intermediate frame  112 , and an inner lamination  121   a  is inserted into the interior of the outer lamination  121   b , and then the inner and outer laminations  121   a  and  121   b  are integrally engaged using the connection ring  123 . 
     Continuously, the rotor  122  engaged to the driving shaft  130  is positioned in a cavity formed between the inner lamination  121   a  and the outer lamination  121   b , and the upper portion of the driving shaft  130  contacts with the upper surface of the first elastic guide support member engaging portion  112   b  and is engaged using the engaging member  170  so that the entire edge portions of the first elastic guide support member  151  contacts with the inner surface of the intermediate frame  112  in a state that the upper portion of the driving shaft  130  passes through the center portion of the first elastic guide support member  151 . 
     The upper portion of the lower frame  113  is closely engaged to the lower portion of the intermediate frame  112 , and the lower portion of the driving shaft  130  contacts with the lower surface of the second elastic guide support member engaging portion  113   a  and is engaged using the engaging member  170  so that the entire edge portions of the second elastic guide support member  152  contact with the inner surface of the lower frame  113  in a state that the lower portion of the driving shaft  130  passes through the center portion of the second elastic guide support member  152 . 
     As shown in FIG. 5, the driving shaft  130  is tightly inserted into the piston  140  in a state that the first elastic guide support member  151  is positioned between the upper support shoulder portion  130   a  of the driving shaft  130  and the piston  140 , and the lower portion of the driving shaft  130  is engaged to the fixing member  160  in a state that the second elastic guide support member  152  is positioned between the lower support portion  130   b  of the driving shaft  130  and the fixing member  160 . 
     At this time, the piston  140  is assembled so that the gap between the outer surface of the piston  140  and the inner surface of the cylinder  110   a  is about 5? when the piston  140  reciprocates within the cylinder  110   a , and the driving shaft engaging holes  151   a  and  152   a  of the first and second elastic guide support members  151  and  152  as shown in FIG.  6  and the cylinder  110   a  are concentrically arranged. 
     As shown in FIG. 5, the upper portion of the driving shaft  130  is tightly inserted into the piston  140  in a state that the first elastic guide support member  151  is positioned between the upper support shoulder portion  130   a  of the driving shaft  130  and the piston  140 . The lower portion of the driving shaft  130  is engaged with the fixing member  160  in a state that the second elastic guide support member  152  is positioned between the lower support shoulder portion  130   b  of the driving shaft  130  and the fixing member  160 . 
     At this time, the piston  140  is assembled so that the gap between the outer surface of the piston  140  and the inner surface of the cylinder is about 5 μm when the piston  140  reciprocates within the cylinder  110   a , and as shown in FIG. 6, the driving shaft engaging holes  151   a  and  152   a  of the first and second elastic guide support members  151  and  152  are concentrical. 
     The upper frame  111  is engaged to the upper portion of the intermediate frame  112  in a state that the piston  140  is inserted into the cylinder  110   a , and the lower portion of the upper frame  111  is sealingly engaged with the upper portion of the sealing shell  114  which surrounds the intermediate frame  112  and the lower frame  113 . 
     The pre-cooling unit  250  is engaged at the upper portion of the cylinder  110   a , and the reproducing unit  240 , the pulse tube  210 , the orifice  220 , and the storing container  230  are sequentially engaged on the upper portion of the cooling unit  250 . 
     The operation of the compressor integrated pulse tube refrigerator of an oil free type according to a first embodiment of the present invention will be explained with reference to the accompanying drawing. 
     When a power is applied to the driving motor  120 , and the rotor  122  reciprocates based on an electric magnetic force, the driving shaft  130  engaged to the rotor  122  reciprocates. Therefore, the piston  140  integrally engaged with the driving shaft  130  reciprocates within the cylinder  110   a  for thereby pumping the working gas in the sealed casing  110 . 
     During the compression cycle, the working gas of the cylinder  110   a  is discharged into the interior of the pre-cooling unit  250 . The working gas in the interior of the pre-cooling unit  250  is cooled to a certain temperature and is flown into the interior of the pulse tube  210  in a state that a sensible heat is stored based on the heat exchange by the reproducing unit  240 . 
     Therefore, the working gas filled in the interior of the pulse tube  210  is flown toward the orifice  220  by the working gas flown into the pulse tube  210  and is compressed, so that the temperature of the compression portion  210   a  of the pulse tube  210  is increased. The thusly increased temperature is adiabatically expanded by the orifice  220 , and the heat is radiated to the outside. 
     In the pulse tube  210 , a high pressure thermal balance state is obtained between the compression cycle and the expansion cycle during the operation of the refrigerator. At this time, the working gas is continuously flown from the pulse tube  210  to the storing container  230  via the orifice  220 , so that the temperature of the pulse tube  210  is gradually decreased. 
     In the expansion cycle, the working gas flown into the pulse tube  210  is flown into the interior of the reproducing unit  240 . At this time, since the amount of the mass flow rate of the working as flown into the pulse tube  210  via the orifice  220  is greatly smaller than that of the mass flow rate of the working gas from the pulse tube  210  via the reproducing unit  240 , the working gas in the pulse tube  210  is adiabatically expanded. 
     The adiabatic expansion of the working gas is generated at the side of the expansion portion, namely, at the portion in which the cold end heat exchanger(not shown) is engaged, so that a ultra low temperature portion is formed at the expansion unit  210   b.    
     In the pulse tube  210 , a low pressure thermal balance state is implemented between the expansion cycle and the compression cycle during the operation of the refrigerator. During the above-described operation, the working gas is continuously flown from the storing container  230  to the pulse tube  210  via the orifice  220 , so that the pressure of the working gas in the pulse tube  210  is increased, and the temperature of the pulse tube  210  is changed to the initial temperature before the operation is started. 
     Therefore, the piston  140  which is moved by receiving a reciprocating movement of the rotator  122  by the first and second elastic guide support members  151  and  152  engaged to the upper and lower portions of the driving shaft  130  reciprocates within the cylinder  110   a  based on a certain gap between the piston  140  and the cylinder  110   a.    
     As described above, in the compressor integrated pulse tube refrigerator of an oil free type according to a first embodiment of the present invention, since the driving unit is integrally formed with the compression including the linear motor compared to the conventional art in which the driving unit of the conventional pulse tube refrigerator is formed of the compressor, the high pressure container, the low pressure container, the oil removing unit, etc., the pulse tube refrigerator is compact. Namely, in the present invention, the high/low pressure containers, the oil removing unit, etc. are removed, so that the number of the assembling processes is significantly decreased, and the assembling processes and the assembling time are significantly decreased. 
     In addition, in the conventional art, a valve is needed for separately communicating the high and low pressure containers and the refrigerating unit for pumping the working gas, so that the working gas which flows through the valve is expanded for thereby decreasing the efficiency of the refrigerating unit. However, in the present invention, the driving unit and the refrigerating unit are directly connected, so that the working gas is pumped only by the reciprocating operation of the piston, whereby a valve is not additionally used for thereby increasing the efficiency of the refrigerating unit. 
     In addition, in the conventional art, the oil removing unit is provided in order to prevent the oil from being flown from the compressor into the refrigerating unit, so teat the oil removing unit is periodically changed. However, in the present invention, since the driving unit supports the resonance movement and straight reciprocating movement of the piston using the support member engaged to the driving shaft, a certain oil such as a lubricating oil is not used for preventing any friction between the outer surface of the piston and the inner wall of the cylinder. Therefore, in the present invention, the period for the maintenance is extended, and the refrigerator is widely applicable to a sensor cooling system such as a satellite system. 
     In the following embodiments of the present invention, since the structure of the refrigerating unit is similar to the first embodiment of the present invention. The structure of the driving unit is explained. 
     The same elements as the first embodiment of the present invention will be given the same reference numerals. 
     In the following descriptions, the descriptions on the directions such as an upper, lower, leftward, and rightward direction are determined based on the directions as shown in FIG.  4 . 
     The compressor integrated pulse tube refrigerator of an oil free type according to a second embodiment of the present invention will be explained with reference to the accompanying drawings. 
     As shown in FIGS. 8 through 11B, the compressor integrated pulse tube refrigerator of an oil free type according to the second embodiment of the present invention includes a sealed casing  280 , a driving motor  120 , a driving shaft  130 , a piston  140 , a first elastic guide support member  251 , and a second elastic guide support member  252 . 
     The structure of the upper frame  111  and the sealed sheel  314  which form the sealed casing  280  is the same as the first embodiment of the present invention except for the structures of the intermediate frame  212 , the lower frame  213 , and the support members  251  and  252 . Therefore, only the different structures will be explained. 
     As shown in FIGS. 9 and 10, four support protrusions  212   c  and  213   b  are inwardly protruded at each inner surface of the intermediate and lower frames  212  and  213 , namely, the upper surfaces or lower surfaces of the support member engaging portions  212   b  and  213   a , in the direction of the interior of the sealed casing  280  for minimizing the area contacting with the inner surfaces of the intermediate and lower frames and the outer surfaces of the first and second elastic guide support members  251  and  252 . 
     At this time, the inner diameters of the support member engaging portions  212   b  and  213   a  are smaller than the outer diameter of the motor support portion  112   a.    
     As shown in FIG. 11A, the inner surfaces of the support protrusions  212   c  and  213   b  may be formed in linear shapes  212   c  and  213   b , and as shown in FIG. 11B, may be formed in curved shapes  212   c ′ and  213   b ′ having the same curved radius as the radiuses of the plate springs  251  and  252 . 
     The processes for assembling the driving apparatus of the compressor integrated pulse tube refrigerator of an oil free type according to a second embodiment of the present invention will be explained. 
     First, the driving motor  120  is engaged to the motor support portion  112   a  of the intermediate frame  212 , and the driving shaft  130  passes through the center portion, and the first elastic support member  251  is engaged to the support member engaging portion  212   b  of the intermediate frame  212 . The lower frame  213  is engaged to the lower portion of the intermediate frame  212 , and the second elastic guide support member  252  having its center portion passed through by the lower portion of the driving shaft  130  is engaged to the second elastic guide support member engaging portion  213   a  of the lower frame  213 . 
     At this time, the support members  251  and  252  are placed on the support member engaging portions  212   b  and  213   a , and the outer surfaces of the support members  251  and  252  are closely contacts with the inner surfaces of the support protrusions  212   c  and  213   b  formed on the upper surface of the support member engaging unit for thereby being concentrically arranged with the cylinder  110   a . In this process, in the case that the structures of the support protrusions  212   c  and  213   b  are linear as shown in FIG. 11A, the diameters of the first and second elastic guide support members  251  and  252  are the same as the length L between the inner surfaces of two support protrusions in the diagonal direction at the intermediate and lower frames, so that the outer surfaces of the support members  251  and  252  tangentially contact with the inner surface centers of the support protrusions  212   c  and  213   b.    
     As shown in FIG. 11B, in the case that the support protrusions  212   c ′ and  213   b ′ have the same radiuses as the radiuses of the support members  251  and  252 , the outer surfaces of the support members  251  and  252  are surface-contacted with the inner surfaces of the support protrusions  212   c ′ and  213   b ′, so that the support members  251  and  252  are fixed. 
     In FIGS. 11A and 11B, L and R represent a tangential contact and a surface, respectively. 
     The upper frame  111  is engaged to the upper portion of the intermediate frame  212  in a state that the piston  140  is positioned to be inserted into the cylinder  110   a , and the sealing shell  114  which surrounds the intermediate frame  212  and the lower frame  213  is engaged to the lower portion of the upper frame  111 . 
     The operation of the compressor integrated pulse tube refrigerator of an oil free type according to the second embodiment of the present invention is the same as the first embodiment of the present invention. Therefore, the description of the same will be omitted. 
     As described above, in the compressor integrated pulse tube refrigerator of an oil free type according to the present invention, a plurality of linear shaped or curved support protrusions are formed to have steps with respect to the support members on the inner surface contacting with the support members so that the edge surfaces of the support members closely contact with the upper and lower portions of the inner surface of the sealed casing in which the support members are concentrically fixed. Therefore, it is easy to fabricate the refrigerator by concentrically arranging the inner surfaces of the intermediate and lower frames closely supported by the support members with the support members for thereby implementing an easier engaging and disengaging operation of the support members, and enhancing the assembling effects. 
     The compressor integrated pulse tube refrigerator of an oil free type according to a third embodiment of the present invention will be explained with reference to the accompanying drawings. 
     As shown in FIGS. 12 through 15, the compressor integrated pulse tube refrigerator of an oil free type according to a third embodiment of the present invention includes a sealed casing  310 , a driving motor  120 , a driving shaft  330 , a piston  340 , a first elastic guide support member  360 , and a second elastic guide support member  152 . 
     The third embodiment of the present invention will be explained by focusing on the structure of the sealed casing  310 , the structure and installation position of the first elastic guide support member  360 , and the engaging method between the first elastic guide support member  360  and the piston  140 , and the structure of the cylinder  310   a  which are the major features of the third embodiment of the present invention. 
     The first elastic guide support member  360  according to the third embodiment of the present invention is installed in the interior of the cylinder  310   a.    
     In the sealed casing  310 , there is provided an upper frame  311 . A cylinder  310   a  into which a piston  340  is inserted and reciprocates therein is installed at the upper frame  311 . A first elastic guide support member  360  is installed at the upper frame  311  for guiding a reciprocating movement of the piston. An intermediate frame  312  is tightly engaged to the lower surface of the upper frame  311 . A driving motor  320  is fixed to the intermediate frame  312 . A lower frame  313  is engaged to the lower surface of the intermediate frame  312 . A second elastic guide support member  152  is engaged to the lower portion of the driving shaft  330  for enabling a reciprocating movement of the piston  340 . A sealing shell  114  surrounds the intermediate frame  312  and the lower frame  313 . The upper portion of the sealing shell  114  is sealingly engaged to the lower surface of the upper frame  311  for preventing a leakage of the working gas from the sealed casing  310 . 
     In detail, as shown in FIG. 13, at the upper end portion of the cylinder  310   a  into which the piston  340  of the upper frame  311  is inserted, the first elastic guide support member engaging groove  310   a - 1  for receiving the first elastic guide support member  360  therein has a radius greater than the cylinder  310   a  and is concentric with respect to the cylinder  310   a.    
     At this time, a connection rod  341  is upwardly extended and is engaged with the first elastic guide support member  360  at the upper center portion of the piston  140 , and the upper end of the driving shaft  330  is tightly inserted into the lower end of the piston  140 . 
     A motor support portion  312   a  is formed on an inner surface of the intermediate frame  312  for engaging an outer side lamination  321   b  of the driving motor  320 , concentrically with respect to the cylinder  310   a.    
     A plurality of second elastic guide support member engaging portions  113   a  (in protrusion shapes) to which the second elastic guide support members  152  are engaged are formed on the inner surface of the lower frame  113  in the radial direction from the inner surface of the lower frame  113 , concentrically with respect to the cylinder  310   a.    
     The driving shaft  330  is integral with the rotor  122  of the driving motor  120  and passes through the stator  121 . The upper portion of the driving shaft  300  is inserted into the piston  140 , and the lower portion of the driving shaft  300  passes through the center portion of the second elastic guide support member  152  and is engaged by the fixing member  160 . 
     The first and second elastic guide support members  360  and  152  are formed of a spiral plate spring, and as shown in FIG. 14, in the first elastic guide support member  360 , the space between the neighboring elastic portions  361  is wide so that the working gas pumped by the piston  340  is effectively flown. As shown in FIG. 15, in the elastic portion  351  of the second elastic guide support member  152 , the space between the neighboring elastic portions  361  is narrow so that the piston  340  smoothly reciprocates. 
     In addition, the connection rod engaging hole  362  and the driving shaft engaging hole  352  formed at the centers of the first elastic guide support member  360  and the second elastic guide support member  152  are concentric. 
     The driving apparatus for a compressor integrated pulse tube refrigerator of an oil free type according to the third embodiment of the present invention is assembled by the following sequence. 
     First, the outer side lamination  121   b  of the driving motor  120  is engaged to the motor support portion  312   a  of the intermediate frame  312 . The inner side lamination  121   a  is inserted into the outer side lamination  121   b . Thereafter, the inner and outer side laminations  121   a  and  121   b  are integrally engaged using the connection ring  123 . A cylindrical rotor  122  engaged with the driving shaft  330  is disposed at the space between the inner and outer side laminations  121   a  and  121   b.    
     Next, the second elastic guide support member  152  is engaged to the lower frame  113 , and the driving shaft  330  is engaged to the second elastic guide support member  152 , and the fixing member  160  is engaged to the lower portion of the driving shaft  330  for thereby fixing the second elastic guide support member  152 . 
     Next, the piston  140  is engaged to the upper portion of the driving shaft  330 , and the upper frame  311  is engaged to the intermediate frame  312  so that the piston  140  is inserted into the cylinder  310   a  to have a certain gap between the piston  140  and the cylinder  310   a . The first elastic guide support member  360  is engaged to the first elastic guide support member engaging groove  310   a - 1  of the cylinder  310   a . At this time, the connection rod  341  of the piston  340  which passes through the center portion of the first elastic guide support member  360  is tightened using the engaging member  380 , so that the first elastic guide support member  360  is integrally engaged with the piston  140 . 
     The sealing shell  114  which surrounds the intermediate frame  312  and the lower frame  113  is engaged to the lower surface of the upper frame  311 . 
     The features of the compressor integrated pulse tube refrigerator of an oil free type according to the third embodiment of the present invention will be explained. 
     The first elastic guide support member  360  engaged to the upper portion of the driving shaft  330  supports in the radial direction of the piston  140  so that the piston  140  which is moved by receiving the linear movement of the rotor  122  reciprocates at a certain gap with respect to the inner wall of the cylinder  310   a.    
     Namely, when the piston  140  reciprocates together with the driving shaft  330 , since the first elastic guide support member  360  engaged with the connection rod  341  which is extended from the piston  140  is engaged with the upper frame  311  at which the cylinder  310  is formed, the piston  140  is not radially leaned in a certain direction. 
     Since the first elastic guide support member  360  and the second elastic guide support member  152  which guide the linear reciprocating movement of the piston  140  are engaged to both ends of the piston  140 , it is possible to significantly prevent a leaning phenomenon by the weight of the piston  140  or an external force compared to when the first elastic guide support member  360  and the second elastic guide support member  152  are engaged in a certain direction of the piston  140 . 
     In addition, since the gap between the cylinder  310   a  and the piston  140  is easily checked after the piston  140  is inserted into the cylinder  310   a , it is easy to implement a concentric engagement of the first elastic guide support member  360 . 
     As described above, in the compressor integrated pulse tube refrigerator of an oil free type according to a third embodiment of the present invention, the support members which enables the piston to continuously reciprocate are installed at both sides of the piston, it is possible to minimize the leaning phenomenon of the piston, so that an abrasion of the piston and cylinder is prevented, and the leakage of the working gas is prevented. When assembling the system, the first elastic guide support member may be assembled after the piston is assembled, so that it is easy to implement a concentricity between the piston and the cylinder. 
     The compressor integrated pulse tube refrigerator for an oil free type according to the fourth embodiment of the present invention will be explained with reference to the accompanying drawings. 
     As shown in FIGS. 16 through 18, the compressor integrated pulse tube refrigerator of an oil free type according to the fourth embodiment of the present invention includes a sealed casing  410 , a driving motor  120 , a driving shaft  430 , a piston  440 , an elastic support member  450 , and a guide support member  460 . 
     The fourth embodiment of the present invention will be explained by focusing on the structure of the sealed casing  410 , the structures and installation positions of the guide support member  460  and the elastic support member  450 , and the structures of the driving shaft  430  and the piston  440 . 
     In the sealed casing  410 , the cylinder  110   a  into which the cylinder  440  is inserted and reciprocates therein is installed at the upper frame  111 . The fixing member  411   a  is engaged for engaging the guide support member  460 . The lower frame  412  is engaged to the lower surface of the upper frame  111 . The driving motor  120  is installed in the interior of the lower frame  412 . The elastic support member  450  engaged to the lower portion of the driving shaft  430  is engaged at the lower frame  412 . The sealing shell  114  is sealingly engaged to the lower surface of the upper frame  111  for surrounding the lower frame  412  and preventing a leakage of the working gas from the sealed casing  410 . 
     The fixing member  411   a  engaged to the upper frame  111  may be separately assembled or the same may be integrally formed of the upper frame  411 . The guide support member engaging portion  411   a ′ is formed in a step form so that the guide support member  460  is placed on the same and is engaged thereto. 
     The motor support portion  412   a  is circumferentially protruded on the inner surface of the lower frame  412  for engaging the stator of the driving motor  120 , and the lower portion of the elastic support member  450  is placed at the center portion of the bottom surface and is supported thereby. 
     An upper portion of the elastic support member  450  is a compression coil spring inserted onto the lower end of the driving shaft  430  and generates a resonance movement during the reciprocating movement of the rotor  122  of the driving motor  120 . In addition, the upper portion of the same is supported by the driving shaft  430 , and the lower portion of the same is supported by the bottom surface of the lower frame  312 . 
     As shown in FIGS. 17 and 18, the guide support member  460  elastically operates during the reciprocating movement of the piston  440 , and an edge portion of the same is engaged to the upper frame  111  for maintaining a linear movement of the piston  440 , and the inner surface of the same is engaged to the driving shaft  430 . The elastic portion  461  is formed of a circular plate spring which may be formed in a spiral shape or a radial shape. The driving shaft engaging hole  462  is concentrically formed with respect to the cylinder  110   a  of the upper frame  111  for implementing a linear movement of the piston  440 . 
     The structure of the driving motor  120  is similar to the first embodiment of the present invention. The inner and outer side laminations  121   a  and  121   b  are engaged at the lower frame  412  of the sealed casing  410 . 
     The driving shaft  430  is integrally engaged with the rotor  122  of the driving motor  120 . The upper support shoulder portion  431  is formed at the driving shaft  430  so that the piston  440  is integrally engaged with the upper portion of the same, and the guide support member(plate spring)  460  is engaged on the upper outer surface. The lower support shoulder portion  432  is formed at the lower portion, so that the compression coil spring which is the elastic support member  450  is inserted into the lower support shoulder portion  432 . 
     The compressor integrated pulse tube refrigerator of an oil free type according to the fourth embodiment of the present invention is assembled as follows. 
     First, the inner and outer side laminations  121   a  and  121   b  of the stator  121  of the driving motor  120  are engaged to the lower frame  412 , and the driving shaft  430  into which the support member  450  is inserted is inserted into the center portion of the inner side lamination  121  a, and the rotor  122  of the driving motor  120  which is integral with the driving shaft  430  is disposed in the hole formed between the inner and outer side laminations  121   a  and  121   b.    
     Continuously, the upper end portion of the driving shaft  430  passes through the driving shaft engaging hole  462  of the guide support member  460 , and an edge portion of the guide support member  460  is engaged to the fixing member  411   a , and the piston  440  is engaged to the upper portion of the driving shaft  430 . The upper frame  111  is engaged to the fixing member  411   a  so that the piston  440  is inserted into the cylinder  410   a , and the upper frame  111  is engaged to the lower frame  412 . 
     The sealing shell  114  is engaged to the lower surface of the upper frame  111  for thereby preventing a leakage of the working gas. 
     The operation of the compressor integrated pulse tube refrigerator of an oil free type according to the fourth embodiment of the present invention will be explained. 
     The guide support member  460  for the compressor integrated pulse tube refrigerator of an oil free type according to the fourth embodiment of the present invention may be a plate shape spring having an elastic portion and guides the linear movements of the driving shaft  430  and the piston  440  during the reciprocating movement of the rotor  122 . The compression coil spring  450  which is the elastic support member engaged to the lower portion of the driving shaft  430  enables a continuous reciprocating movement of the driving shaft  430  and the piston  440  by inducing a resonance movement of the rotor  122 , so that the elastic support member  450  is not applied with an over load for thereby preventing any damages of the same. When fabricating and assembling the elastic support member  450 , it is easy to implement a concentric arrangement with respect to the guide support member  460 , and the guide support member  460  may be formed in various shapes. 
     In the fourth embodiment of the present invention, the sealed casing is formed of two frames and the sealing shell, so that the size of the pulse tube refrigerator is small. 
     As described above, in the compressor integrated pulse tube refrigerator of an oil free type according to the fourth embodiment of the present invention, the elastic support member which implements a continuous reciprocating movement of the piston is substituted with a compression coil spring which is capable of enduring a certain degree fatigue limit, so that the damage of the elastic support member is prevented, and the fabrication and assembly of the elastic support member is easy. In addition, the guide support member is formed in various shapes, and the size of the pulse tube refrigerator may be small. 
     The compressor integrated pulse tube refrigerator of an oil free type according to a fifth embodiment of the present invention will be explained with reference to the accompanying drawings. 
     As shown in FIGS. 19 through 21, the driving unit of the compressor integrated pulse tube refrigerator of an oil free type according to the fifth embodiment of the present invention includes a sealed casing  510 , a driving motor  120 , a piston  530 , and a plurality of elastic guide support members  541  and  542 . 
     In the sealed casing  510 , the cylinder  110   a  into which the piston  530  is inserted and reciprocates therein is installed at the upper frame  111 , and the edge portions of two elastic guide support members  541  and  542  are engaged at the inner portion of the upper frame  111 . The lower frame  512  in which the driving motor  120  is installed is engaged to the lower surface of the upper frame  111 . The sealing shell  114  is sealingly engaged to the lower surface of the upper frame  111  for surrounding the lower frame  512  for thereby preventing a leakage of the working gas. 
     In detail, a circular fixing member  311   a  is integrally engaged to the lower surface of the upper frame  111  for engaging the elastic guide support members  541  and  542 . The elastic guide support members  541  and  542  engaged to the piston are engaged at both surfaces of the fixing member  311  a at a certain distance therebetween. A ring shape spacer  550  is disposed between the elastic guide support members  541  and  542  so that the driving motor  120  does not receive a certain load by the support members  541  and  542  having different cycles. 
     As shown in FIGS. 20 and 21, four protruded support member engaging portions  511   a - 1  are formed at both inner ends of the fixing member  511   a  on the same circumferential portions so that the elastic guide support members  541  and  542  have a certain elastic force, respectively. 
     The piston  530  according to the fifth embodiment of the present invention includes a head portion  531  inserted into the cylinder  510   a , and a shaft portion  532  extended from the head portion  531  and engaged to the elastic guide support members  541  and  542 . A threaded portion  532   b  is formed at the extended lower portion of the shaft portion  532  and is engaged with a nut shaped engaging member  522   a  engaged at the center portion of the rotor  122 . 
     The elastic guide support members  541  and  542  are formed of a spiral type circular plate spring, respectively. As shown in FIG. 21, the edge portions of the elastic guide support members  541  and  542  are engaged to the support member engaging portions  511   a - 1  of the fixing member  511   a  of the upper frame  511 , and the center portion of the same is integrally engaged to the fixing member  511   a  by a plurality of lengthy bolts  560  which pass through the support members  541  and  542 . The upper surface of the first elastic guide support member  541  closely contacts with the lower surface of the head portion  531  of the piston  530 . The lower surface of the second elastic guide support member  542  closely contacts with the upper surface of the nut shaped engaging member  522   a  engaged with the shaft portion  532  of the piston  530 . 
     In addition, the elastic guide support members  541  and  542  each include a piston engaging hole  532 ′, through which the piston  530  passes through, formed at the center portions of the same. The piston engaging hole  532 ′ is concentrically formed with respect to the cylinder  110   a  of the upper frame  111  so that the outer surface of the piston  530  does not contact with the inner surface of the cylinder  110   a.    
     The driving apparatus for a compressor integrated pulse tube refrigerator of an oil free type according to the fifth embodiment of the present invention is assembled in the following method. 
     First, the shaft portion  532  of the piston  530  is inserted into the first elastic guide support member  541  and the spacer  550 , and the edge portion of the first elastic guide support member  541  is engaged to the support member engaging portion  511   a - 1  formed at the upper portion of the fixing member  511   a.    
     The second elastic guide support member  542  is inserted into the shaft portion  532  of the piston  530 , and the edge portion of the second elastic guide support member  542  is engaged to the lower surface of the support member engaging portion  511   a - 1  of the fixing member  511   a.    
     The shaft portion  532  of the piston  530  is threaded to the engaging member  522   a  which is integral with the rotor  122 . 
     The upper frame  511  and the fixing member  511   a  are engaged so that the head portion  531  of the piston  530  is inserted into the cylinder  110   a.    
     The inner and outer side laminations  121   a  and  121   b  of the stator  121  of the driving motor  120  are fixedly engaged to the lower frame  512 , and the rotor  122  is inserted between the inner and outer side laminations  121   a  and  121   b , and the upper frame  511  and the lower frame  512  are engaged. 
     Next, the lower surfaces of the upper frame  111  and the sealing shell  114  are sealingly engaged in such a manner that the lower frame  512  is surrounded for thereby preventing a leakage of the working gas. 
     The operation of the compressor integrated pulse tube refrigerator of an oil free type according to the fifth embodiment of the present invention will be explained. 
     In the fifth embodiment of the present invention, a small phase difference occurs at the vibration cycle between the rotor  122  and the piston  530 , so that the driving motor  120  receives a load. In the present invention, the spacer  550  is closely disposed between the support members  541  and  542 , it is possible to decrease the load due to the phase difference of the vibration cycle, so that the driving motor  120  receives less loads. 
     In the fifth embodiment of the present invention, the elastic guide support members  541  and  542  are engaged at the upper frame  111 . Therefore, one frame is removed compared to the first embodiment of the present invention. In addition, since the elastic guide support members  541  and  542  are installed above the driving motor  120 , the number of the elements which need a high accuracy process is decreased. The driving shaft is not additionally needed, and the rotor  122  and the piston  530  are directly connected. It is easy to concentrically arrange the driving motor  120  and the lower frame  512  in which the driving motor  120  is installed. Preferably, the driving motor  120  and the piston  530  may be separately assembled. 
     Since the piston  530  is directly engaged to the rotor  122 , it is possible to minimize the load applied to the driving motor  120 , and a compact size refrigerator may be implemented. 
     As described above, in the compressor integrated pulse tube refrigerator of an oil free type according to the fifth embodiment of the present invention, the elastic guide support members which enable a continuous reciprocating movement of the piston is disposed between the piston and the rotor, so that it is possible to decrease the number of the elements which need a high accuracy process. In addition, the driving shaft for transferring the driving force of the driving motor is removed, so that the driving motor and the piston is separately assembled. Therefore, it is possible to implement a concentric assembly and productivity. The processing accuracy of each frame is increased, and the load applied to the driving motor is decreased. A compact size refrigerator may be implemented. 
     The compressor integrated pulse tube refrigerator of an oil free type according to a sixth embodiment of the present invention will be explained with reference to the accompanying drawings. 
     As shown in FIGS. 22 through 25, the driving unit of the compressor integrated pulse tube refrigerator of an oil free type according to the sixth embodiment of the present invention includes a sealed casing  610 , a driving motor  120 , a driving shaft  630 , a piston  140 , an elastic support member  151 , and a linear bearing  660  which is disposed in the stator  121  of the driving motor  120  and operates as a guide support member. 
     In the sealed casing  610 , the cylinder  110   a  into which the piston  140  is inserted and reciprocates therein is provided in the upper frame  111 . The elastic support member  151  for guiding a continuous reciprocating movement of the piston  140  is engaged to the lower frame  112  engaged to the upper frame  111 . The sealing shell  114  is sealingly engaged to the lower surface of the upper frame  111  for surrounding the lower frame  112  for thereby preventing a leakage of the working gas from the sealed casing  610 . 
     A circular shape motor support portion  112   a  is formed on an inner circumferential surface of the lower frame  112  for engaging the stator  121  of the driving motor  120 , and a plurality of protrusion shape support member engaging portion  112   b  are formed for engaging the elastic support member  151 . 
     Here, the structure of the driving motor  120  is the same as the first embodiment of the present invention. The outer side lamination  121   b  is engaged to the lower frame  112  of the sealed casing  610 . The inner lamination  121   a  is integrally engaged with the outer side lamination  121   b  by the connection ring  123 . 
     The driving shaft  630  is integral with the rotor  122  of the driving motor  120  and passes through the center portion of the stator  121 . The upper portion of the driving shaft  630  is integrally engaged to the elastic support member  151 , and the outer surface of the lower portion of the driving shaft  630  is slidably contacts with the linear bearing  660  which is the guide support member inserted into the inner side lamination  121   a  and is supported in the radial direction. 
     The elastic support member  151  is a known spiral shape circular plate spring. As shown in FIG. 24, the driving shaft engaging hole  352  formed at the center portion is formed concentrically with respect to the cylinder  110   a  of the upper frame  111  for implementing a linear movement of the piston  140 . 
     The linear bearing  660  is used for radially supporting the piston  140 . The outer surface of the linear bearing  660  is inserted into the center portion of the stator  121 , and the inner surface of the same slidably contacts with the outer surface of the driving shaft  630  and is concentrical with respect to the driving shaft engaging hole  352  of the elastic support member  151  and the cylinder  110   a.    
     In the drawings, reference numeral  661  represents an insertion bush,  662  represents a retainer, and  663  represents a ball bearing. 
     The compressor integrated pulse tube refrigerator of an oil free type according to the sixth embodiment of the present invention is assembled by the following methods. 
     First, the outer side lamination  121   b  of the driving motor  120  is engaged to the motor support portion  112   a  of the lower frame  112 , and the inner side lamination  121   a  is inserted into the center portion of the outer side lamination  121   b  at a certain interval and is fixed by the connection ring  123 . The driving shaft  630  is engaged to the rotator  122 , and the driving shaft  630  is inserted into the center portion of the inner side lamination  121   a  so that the rotator  122  is disposed in the space formed between the inner and outer side laminations  121   a  and  121   b.    
     At this time, the lower portion of the driving shaft  630  is inserted into the linear bearing  660  inserted into the lower center portion of the inner side lamination  121   a.    
     Next, the upper portion of the driving shaft  630  is inserted into the driving shaft engaging hole  352  as shown in FIG.  24  and is engaged to the elastic support member  151 , and the edge portion of the elastic support member  1541  is engaged to the lower frame  112 . The piston  140  is integrally engaged to the upper portion of the driving shaft  630 , and the upper frame  111  is engaged to the lower frame  112  so that the piston  140  is inserted into the cylinder  110   a.    
     The upper portion of the sealing shell  114  is sealingly engaged to the lower surface of the upper frame  111  for thereby preventing a leakage of the working gas. 
     The operation of the driving apparatus for a compressor integrated pulse tube refrigerator of an oil free type according to the sixth embodiment of the present invention will be explained. 
     In the sixth embodiment of the present invention, the elastic support member  151  engaged to the upper portion of the driving shaft  630  stores the linearly reciprocating movement of the rotor  122  as an elastic energy by receiving the reciprocating movement of the driving shaft  630 . The thusly stored elastic energy is changed to the linear movement, so that the rotor  122  is resonantly moved, and the piston  140  continuously reciprocates. 
     The linear bearing  660  which is the guide support member into which the lower portion of the driving shaft  630  is inserted radially supports the piston  140  so that the piston  140  is moved by receiving the linear movement of the rotator  122  reciprocates at a certain gap between the piston  140  and the cylinder  110   a.    
     The elastic support member  151  is formed of the plate spring  150  in which the driving shaft engaging hole  352  is formed concentrically with respect to the cylinder  110   a , so that the piston  140  continuously reciprocates. The guide support member  660  is used for radially supporting the piston  140  by inserting the linear bearing  660  onto the driving shaft  630 , so that it is possible to easily implement a concentric arrangement when fabricating and assembling the corresponding elements. 
     As another example of the sixth embodiment of the present invention, when the guide support member is inserted into the upper portion of the inner side lamination  121   a , the length of the driving shaft  630  may be decreased, so that the load applied to the driving motor  120  is minimized, and a small sized refrigerator is implemented. 
     As described above, in the compressor integrated pulse tube refrigerator of an oil free type according to the sixth embodiment of the present invention, since there are provided an elastic support member which enables a continuous linear movement of the piston and a linear bearing which is the guide support member inserted into the center portion of the stator of the driving motor, it is possible to easily implement the concentric arrangement of the support members. The number of the elements is decreased. The length of the driving shaft may be decreased. The load applied to the driving motor is decreased, and a small sized refrigerator may be fabricated. 
     The compressor integrated pulse tube refrigerator for an oil free type according to the seventh embodiment of the present invention will be explained with reference to the accompanying drawings. 
     As shown in FIG. 26, the driving unit of the compressor integrated pulse tube refrigerator of an oil free type according to the seventh embodiment of the present invention includes a sealed casing  710 , a driving motor  120 , a driving shaft  730 , a piston  140 , a first elastic guide support member  751 , and a second elastic guide support member  752 . 
     The features of the seventh embodiment of the present invention will be explained by focusing on the structure of the sealed casing  710 , the structures and installation positions of the first and second elastic guide support members  751  and  752 , and the structures of the spring engaging portion  712   b  and  713   a.    
     In the sealed casing  710  according to the seventh embodiment of the present invention, there is provided an upper frame  711  in which the cylinder  110  is provided in a protruded shape. The piston  140  is inserted into the cylinder  110   a  and reciprocates therein. In addition, there is provided a lower frame  713  engaged to the lower surface of the upper frame. The driving motor  120  is engaged in the interior of the lower frame  713 . The edge portion of the first elastic guide support member  751  which is engaged to the upper portion of the driving shaft  730  and enables a linear reciprocating movement of the piston is engaged to the lower frame  713 . A plurality of sealing shells  715  are provided below the lower frame  713  for preventing a leakage of the working gas from the sealed casing  710 . 
     The sealing shell  715  is formed to have a uniform thickness and a certain area. The support members  751  and  752  are formed of the plate spring. 
     The construction according to the seventh embodiment of the present invention will be explained. The upper portion of the driving shaft  730  is inserted into the lower center portion of the piston  140 . 
     The first elastic guide support member engaging portion  712   b  is protruded from the inner surface of the lower frame  713  in the radial direction at the inner upper portion of the lower frame  713 , concentrically with respect to the cylinder  110   a , for engaging the first elastic guide support member  751 . The lower portion of the lower frame  713  is radially extended in the downward direction, and the extended portion is the first elastic guide support member engaging portion  713   a  for engaging the first elastic guide support member  751 . 
     The outer diameter of the second elastic guide support member  752  is greater than the outer diameter of the first elastic guide support member  751 . 
     The driving shaft  730  is integral with the rotor  122  of the driving motor  120  and passes through the stator  121 . The upper portion of the driving shaft  730  is integrally inserted into the piston  140 , and the lower portion of the driving shaft  730  passes trough the center portion of the second elastic guide support member  752  and is engaged to the engaging member  160 . 
     An upper support member  730   a  which contacts with an upper center portion of the first elastic guide support member  751  is formed at an upper outer portion of the driving shaft  730  at the lower portion of the piston  140 . In addition, a lower support shoulder portion  730   b  which contacts with the upper center portion of the second elastic guide support member  752  is formed at an outer portion of the driving shaft  730  disposed at the upper portion of the fixing member  160  below the driving shaft  730 . 
     The sealing shell  715  and the lower frame  713 , and the upper frame  711  and the lower frame  713  are engaged by the engaging members B, and the sealing members S are provided therebetween, respectively. 
     In the seventh embodiment of the present invention, the inner diameter of the body portion of the lower frame  713  into which the linear motor  120  is inserted is the same as the inner diameter of the upper frame  711 , and the inner diameter of the first elastic guide support member engaging portion  713   a  formed for engaging the second elastic guide support member is greater than the inner diameter of the body portion, so that the heat is effectively radiated from the linear motor  120 , and the first elastic guide support member  751  and the second elastic guide support member  752  which support the driving shaft  730  are engaged to the lower frame  713 . 
     At this time, since the outer diameters of the first elastic guide support member  751  and the second elastic guide support member  752  are different, the entire elastic constants of the first elastic guide support member  751  and the second elastic guide support member  752  are controlled to be a resonance frequency. 
     As described above, in the compressor integrated pulse tube refrigerator according to a seventh embodiment of the present invention, first and second elastic guide support members  751  and  752  are engaged at the body frame for supporting the driving shaft which transfers the driving force of the linear motor to the piston inserted into the cylinder. Therefore, it is easy to adjust a concentricity of the engaging portions for engaging the first elastic guide support member  751  and the second elastic guide support member  752 . In addition, an assembling error of the first elastic guide support member  751  and the second elastic guide support member  752  is decreased, so that it is possible to implement a concentricity of the piston connected with the driving shaft and an accurate linear movement of the piston. The numbers of the parts and the fabrication processes are decreased, so that the fabrication cost is decreased, and the productivity of the assembling processes is enhanced, 
     In the seventh embodiment of the present invention, since the number of the parts is decreased, the processes for fabricating the parts are decreased, and the number of the part assembling processes is decreased. 
     The compressor integrated pulse tube refrigerator for an oil free type according to an eighth embodiment of the present invention will be explained with reference to the accompanying drawings. 
     The inner side lamination  121   a  of the stator is engaged at the inner center portion of the sealed casing  810  by the engaging member  806  in which the sealing material  805  is provided. On the outer surface of the inner side lamination  121   a  of the sealed casing  810 , the outer side lamination  121   a  formed in the sealed casing  810  is provided in the interior of the sealed casing  810  by the engaging member  806   a  having a hollow disk type connection member  807  (washer, etc.) inserted thereto. 
     The driving shaft  830  which is disposed between the inner and outer side laminations  121   a  and  121   b  and is engaged with the rotator  122  engaged with the magnet  122   b  to be opposite to the coil  121   c  passes through the inner side lamination  121   a  in the sealed casing  810 , and at the upper portion of the driving shaft  830 , the piston  840  which is inserted into the cylinder  810   a  of the sealed casing  810  and reciprocates with the driving shaft  830  for thereby pumping the working gas is integrally installed with respect to the driving shaft  830 . 
     In addition, the sealing cover  870  is engaged at the lower portion of the sealed casing  810  by the engaging member  806   b  for preventing a leakage of the working gas. A sealing material  805   a  is inserted between the lower portion of the sealed casing  810  and the sealing cover  870  for implementing a sealed state therebetween. The adjusting member  880  is engaged at the center portion of the sealing cover  870 . The elastic coil spring  890  is supportedly disposed between the support plate  831  formed at the lower portion of the driving shaft  830  and the support plate  881  formed at the upper portion of the adjusting member  880 . A tension adjusting ring  891  is inserted between the sealing cover  870  and the adjusting member  880  for adjusting an initial compression state of the coil spring  890 . 
     When assembling the driving unit  800  according to the eighth embodiment of the present invention, a sleeve  804  in which the linear bearing  803  is inserted for implementing a linear reciprocating movement of the piston  840  is inserted into the lower inner surface of the cylinder  810   a.    
     The inner side lamination  121   a  of the stator  121  of the driving motor  120  is provided at the inner center portion of the sealed casing  810 , and the engaging member  806  into which the sealing material  805  is inserted from the upper portion of the sealed casing  810  is engaged with the inner side lamination  121   a , and the inner side lamination  121   a  is engaged in the interior of the sealed casing  810 . The outer side lamination  121   b  in which a plurality of coils  121   c  are engaged on the outer surface of the inner side lamination  121   a  in the interior of the sealed casing  810  is engaged in the interior of the sealed casing  810  by the engaging member  806   a  into which the hollow disk type connection member  807  is inserted. The piston  840  integrally formed at the upper portion of the driving shaft  830  is inserted into the cylinder  810   a  of the sealed casing  810 . When engaging the rotor  122  to the driving shaft  830 , the rotor  122  is disposed between the inner and outer side laminations  121   a  and  121   b.    
     In a state that the adjusting member  880  is roughly engaged by inserting the tension adjusting ring  891  into the center portion of the sealing cover  870  from the lower portion to the upper portion, the coil spring  890  is inserted between the support plate  881  formed at the upper portion of the adjusting member  880  and the support plate  831  formed at the lower portion of the driving shaft  830  for thereby engaging the adjusting member  880 . 
     At this time, since the tension adjusting ring  891  is inserted between the center portion of the sealing cover  870  and the adjusting member  880  inserted into the center portion, it is possible to implement a sealed state. In addition, it is possible to effectively adjust the elastic force(repulsion force) of the coil spring  890  based on the linear reciprocating movement of the piston  840  by adjusting the initial compression force of the coil spring  890  and the thickness of the tension adjusting ring  891 . 
     As shown in FIG. 30, in another example of the eighth embodiment of the present invention, the diameter of the lower portion of the cylinder  810   a ′ formed at the upper center portion of the sealed casing  810 ′ may be wider than the diameter of the upper portion of the same. 
     As shown in FIG. 30, the sleeve  804 ′ having a linear bearing  803 ′ for supporting a linear reciprocating movement of the piston  840   a ′ is inserted into the lower portion of the cylinder  810   a ′ in such a manner that the inner diameter of the linear bearing  803  is greater than the inner diameter of the cylinder  810   a ′, and is engaged by the engaging member  806   c  in the interior of the sealed casing  810 ′. The outer surface of the piston  840   a ′ which is opposite to the linear bearing  803 ′ and the sleeve  804 ′ is expanded to correspond with the inner diameter of the linear bearing  803 ′, so that a certain gap is obtained between the inner surface of the cylinder and the outer surface of the piston. 
     Since the operation of the compressor integrated pulse tube refrigerator of an oil free type according to the eighth embodiment of the present invention is the same as the operation of the first embodiment of the present invention, the description thereof will be omitted. 
     As described above, in the eighth embodiment of the present invention, the frame of the driving unit which is adapted to the compressor integrated pulse tube refrigerator of an oil free type and generates a driving force is integral, and the driving shaft and the piston are integral, so that the structure of the driving unit is simplified, and the system is compact. In addition, since a certain part such as a connection ring, etc. is not used, the fabrication cost is decreased. The assembly of the parts becomes easier compared to the conventional art, so that the productivity is significantly increased. 
     A preferred structure for engaging the plate spring which is used in the first through seventh embodiments of the present invention will be explained with reference to the accompanying drawing. 
     As shown in FIG. 31 a , the plate spring engaging structure includes a sealed casing  940  having a recess  943  horizontally formed on an outer surface of the through holes  941  and  942  based on the different diameters of the through holes  941  and  942  and a plurality of female screw holes  944  formed at the recess  943 , a support member  950  having its inner portion contacting with the recess  943  and a screw hole  951  corresponding to the female screw hole  944  of the sealed casing  940 , a plate spring  920  in which a screw hole(not shown) corresponding to the female screw hole  944  of the sealed casing  940 , for thereby being disposed on the upper surface of the support member  950 , and a plurality of engaging members  960 . 
     The female screw hole  944  formed at the recess  943  is formed at a certain interval, and as shown in FIG. 31 b , the number of the female screw holes  944  is preferably  4 . 
     As shown in FIGS. 32 a  and  32   b , in the support member  950 , a plurality of protrusions  953  are formed in a semi-circular shape on an inner surface of the ring portion  952  having a certain thickness and width at a certain interval, and the screw hole  951  passes through the protrusions  953 . 
     The number of the protrusions  953  corresponds with the number of the female screw holes  944  of the sealed casing  940 . 
     The thickness of the support member  950  is determined so that the plate spring  920  does not contact with the sealed casing  940  when the plate spring  920  vibrates. 
     The maximum width of the protrusion  953  of the support member  950  is the same as or smaller than the width of the recess  943 . 
     The engaging member  960  is preferably engaged using an engaging screw. 
     When assembling the parts, the screw hole  951  of the support member  950  and the female screw hole  944  are disposed on the recess  943  of the sealed casing  940 , and the plate spring  920  is disposed on the support member  950  s that the screw hole of the plate spring  920  is arranged with the screw hole  951  of the support member  950 . 
     The engaging screw, which is the engaging member  960 , is inserted into the female screw hole  944  of the sealed casing  940 , the screw hole  951  of the support member  950 , and the screw hole of the plate spring  920 , and the support member  950  and the plate spring  920  are fixed to the sealed casing  940 . 
     As shown in FIGS. 33 a  and  33 C, as another embodiment of the support member  950 , the support member  950  has a certain thickness and area and includes a plurality of rings  950 ′ each having a through screw hole  951 ′, and the number of the rings  950 ′ corresponds to the number of the female screw holes  944  of the sealed casing  940 . 
     At this time, the outer diameter of the ring  950 ′ is the same as or smaller than the recess  943  formed in the sealed casing  940 . 
     There are provided a plurality of the rings  950 ′ on the recess  943  to correspond with the female screw holes  944  of the recess  943  of the sealed casing  940 , and the plate spring  920  is provided thereon and is engaged by the engaging member  960  which is the engaging screw. 
     The operation and effects of the plate spring engaging structure according to the present invention will be explained. 
     In the plate spring engaging structure according to the present invention, a shaft or a certain mass is engaged at the center portion of the plate spring  920  in the sealed casing  940 , so that an elastic energy stored by absorbing or releasing an impact applied to the shaft or the mass has a certain inherent vibration and is transferred to the outside. 
     In the present invention, since the support member  950  is engaged between the sealed casing  940  and the plate spring  920 , so that it is easy to engage the plate spring  920 , and the contact area between the plate spring  920  and the sealed casing  940  is decreased. 
     Namely, in the present invention, when fabricating the sealed casing  940 , the through holes  941  and  942  having different diameters are formed in the interior of the sealed casing  940 , and then the female screw hole  944  is formed. Thereafter, the support member  950  may be fabricated based on a press fabrication method by the mass production system. 
     In addition, in the present invention, the female screw hole  944  in which the engaging member  960 (engaging screw) is engaged at the recess  943  in the sealed casing  940 , and the support member  950  is engaged at the portion contacting with the plate spring  920 , so that it is possible to minimize the contact area of the sealed casing  940  and the plate spring  920 . 
     As described above, in the plate spring engaging structure according to the present invention, the contact area of the sealed casing and the plate spring is minimized, so that a maximum displacement of the plate spring is obtained, and the friction loss is decreased, and the inherent characteristic of the plate spring is maximized. In addition, the fabrication of the parts for engaging the plate spring is more easily implemented for thereby decreasing the fabrication cost. 
     In addition, it is easy to implement a concentricity and linearity of two plate springs, and an additional frame fabrication is not needed in the present invention, so that the fabrication cost and time are significantly decreased. 
     Although the preferred embodiment of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as recited in the accompanying claims.