Patent Publication Number: US-2017350250-A1

Title: Free rotary fluid machine

Description:
TECHNICAL FIELD 
     The present invention relates to a fluid machine, and more particularly, to a free rotary fluid machine in which an auxiliary tip seal is formed in a tip seal, such that a space formed by a main body, a rotor, and a tip seal is sealed by improving performance of the main body and the tip seal when the rotor is rotated, thereby preventing a leak of an introduced working fluid. 
     BACKGROUND ART 
     In general, an internal combustion engine, which is widely used for various types of vehicles, ships, aircrafts, tractors, locomotives, and the like, has a piston that rectilinearly moves in a cylinder of the engine, such that the piston is moved downward by explosive power of fuel, and a crank rod, which is connected to the piston, is connected to the crank shaft so as to convert the rectilinear downward movement of the piston in terms of a rotational motion of the crank shaft, thereby obtaining rotational power. 
     A typical internal combustion engine in the related art has a problem in that impact and friction caused by the piston are not unevenly applied to the crank shaft when the crank shaft and the crank rod mechanically convert a rectilinear motion into a rotational motion, such that noise and vibration severely occur, mechanical durability deteriorates, efficiency greatly deteriorates, and particularly, a material such as a ceramic material vulnerable to impact cannot be used. 
     Meanwhile, to solve the problems of the existing internal combustion engine, there has been developed a rotary engine having a simple structure in which a plurality of explosion spaces is provided in a rotor, and an air inlet port and a gas discharge port are formed outside the rotor, such that fuel or a fluid is supplied to the explosion spaces, the explosion spaces are rotated by rotational force of the rotor, combustion gas may be naturally discharged when the explosion space meets the gas discharge port, and air may be naturally introduced when the explosion space meets the air inlet port. 
     However, the rotary engine cannot solve the defects of the existing internal combustion engine, and has serious problems in that combustion gas in the rotary engine cannot be completely discharged, and air cannot be completely introduced, and as a result, driving performance and efficiency extremely deteriorate, air and combustion gas are insufficiently introduced and discharged when the rotary engine operates at a low speed, and air and combustion gas are excessively introduced and discharged when the rotary engine operates at a high speed. 
     In addition, vibration and abrasion occur because the rotor of the rotary engine rotates about an eccentric axis, and a Wankel engine, which is known as a representative rotary engine, has a problem in that vibration inevitably occurs and durability and airtightness deteriorate because a rotor rotates eccentrically about a rotating shaft. 
     To solve the aforementioned problems, the applicant of the present application has proposed Korean Patent No. 10-0652557 (registration date: Nov. 24, 2006) entitled “free piston rotary engine”. However, the technology disclosed in Korean Patent No. 10-0652557 has problems in that because a contact area between a blade and a tip seal is small, a contact state between the blade and the tip seal is not maintained when centrifugal force, which occurs when a rotor rotates, is applied to the blade, and the blade deviates outward in a direction in which the centrifugal force is applied, and as a result, the blade cannot rotate, such that the rotary engine cannot be used. Further, the technology has problems in that vibration and abrasion still occur on the rotor due to a sliding motion between the rotor and the tip seal, and as a result, durability and airtightness of the rotary engine deteriorate. 
     Furthermore, when centrifugal force caused by the rotation is applied to the blade, the blade is withdrawn from the tip seal, and the blade collides with a stator, and as a result, the rotor cannot be rotated. Further, there is a problem in that a contact state of the tip seal is deformed, such that a leak occurs in a combustion chamber, a collision occurs as the blade moves, or abrasion occurs. 
     Meanwhile, the technology disclosed in Korean Patent No. 10-0652557 is described as being applied to an engine which uses gasoline, diesel, hydrogen, and the like as fuel, and Korean Patent No. 10-0652557 also describes that the technology may also be used for a turbine that uses any one of steam, air, and gas. 
     However, the structure of the engine disclosed in Korean Patent No. 10-0652557 may be substantially applied only to the engine, but there is a limitation in applying the structure to a turbine and a compressor. 
     DISCLOSURE 
     Technical Problem 
     An aspect of the present invention provides a free rotary fluid machine in which close contact performance between a tip seal and an inner circumferential surface of a main body is improved even though the tip seal, which is in contact with the inner circumferential surface of the main body, is abraded when a rotor is rotated in the main body, such that a volume space formed among the inner circumferential surface of the main body, a blade, and the tip seal is sealed, thereby preventing a leak of an introduced working fluid. 
     An aspect of the present invention also provides a free rotary fluid machine capable of maintaining a surface-to-surface contact state between a blade and a tip seal even though centrifugal force is applied to the blade. 
     Technical Solution 
     According to an aspect of the present invention, there is provided a free rotary fluid machine including: a main body which is provided in a hollow cylindrical shape, and has an elliptical inner circumferential surface; a rotor which is provided in the main body, and rotates about the same rotation center as the main body; tip seals which are provided at one side of the rotor so as to be in contact with the inner circumferential surface of the main body; and blades which are provided between the tip seals provided adjacent to each other, and supported by the tip seals, in which the blade has one end surface that faces the inner circumferential surface of the main body, and the other end surface that is opposite to one end surface, and centers of radii of curvature of one end surface and the other end surface are positioned at the same side. 
     The blade may have tip seal contact portions that connect one end surface and the other end surface, and the tip seal contact portion may be formed to have the same curved surface as the tip seal. 
     One end portion of the tip seal in a longitudinal direction of the tip seal may be formed in a cylindrical shape having a circular cross section and may be in contact with the inner circumferential surface of the main body, the other end portion of the tip seal may be formed in a hexahedral bar shape having a quadrangular cross section, and the tip seal contact portion may be in surface-to-surface contact with one end portion from a point at which one end portion meets the other end portion. 
     A portion where the tip seal contact portion meets one end portion may be formed to have a curved surface. 
     An auxiliary tip seal, which is formed to protrude toward the inner circumferential surface of the main body, may be provided at one end portion of the tip seal, and the auxiliary tip seal may be rotated by the rotor while maintaining a surface-to-surface contact state with the inner circumferential surface of the main body. 
     The auxiliary tip seal may include: a sealing member which is drawn in or pulled out from the tip seal; and an elastic support body which supports the sealing member and enables the sealing member to be drawn in or pulled out from the tip seal. 
     The sealing member may be made of a ceramic material. 
     The free rotary fluid machine may further include a pressing member which is provided between the tip seal and the rotor and elastically presses the tip seal. 
     A width of the sealing member may be smaller than a width of an opening which is formed at one end portion of the tip seal such that the sealing member is inserted into the opening. 
     At least one intake port and at least one exhaust port may be provided in the main body, and the intake port and the exhaust port may be provided radially based on the rotation center of the main body. 
     Advantageous Effects 
     According to the exemplary embodiments of the present invention, a space formed among the inner circumferential surface of the main body, the rotor, and the tip seal is sealed by the auxiliary tip seal, and as a result, it is possible to reduce friction between the tip seal and the main body and to prevent a leak of the introduced working fluid. 
     In addition, according to the exemplary embodiments of the present invention, since the auxiliary tip seal is drawn in and pulled out from the tip seal, a position of the blade, which is supported between the tip seals provided adjacent to each other, may be automatically moved. 
     In addition, according to the exemplary embodiments of the present invention, the tip seal comes into close contact with the inner circumferential surface of the main body as the tip seal is moved by a length or a thickness of the blade toward the inner circumferential surface of the main body even though no centrifugal force is applied, and the tip seal is forcibly pressed against the inner circumferential surface of the main body even though the tip seal is abraded to any limit point, and as a result, it is possible to maintain performance of the tip seal. 
     In addition, according to the exemplary embodiments of the present invention, the pressing member is provided between the tip seal and the rotor, and as a result, the tip seal may be retracted toward the rotation center of the rotor or may be moved forward in a direction opposite to the rotation center. 
     In addition, according to the exemplary embodiments of the present invention, the inner surface and the outer surface of the blade have almost the same shape, and as a result, it is possible to increase an area in which both ends of the blade in the rotation direction of the blade are in contact with the curved surfaces of the tip seals, respectively, and for this reason, the blade and the tip seal may be moved while maintaining the surface-to-surface contact state between both ends of the blade and the tip seals even in a case in which centrifugal force is applied to the blade. 
    
    
     
       DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective view illustrating a rotary fluid machine according to an exemplary embodiment of the present invention; 
         FIG. 2  is a perspective view illustrating a tip seal illustrated in  FIG. 1 ; 
         FIG. 3  is a perspective view illustrating a blade illustrated in  FIG. 1 ; 
         FIG. 4  is a view for explaining a case in which the rotary fluid machine according to the exemplary embodiment of the present invention is a turbine; 
         FIG. 5  is a view for explaining a case in which the rotary fluid machine according to the exemplary embodiment of the present invention is a compressor; and 
         FIG. 6  is a view for explaining a case in which the rotary fluid machine according to the exemplary embodiment of the present invention is a compander. 
     
    
    
     BEST MODE 
     Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the technical field to which the present invention pertains may easily carry out the exemplary embodiment. The present invention may be implemented in various different ways, and is not limited to the exemplary embodiments described herein. 
     It is noted that the drawings are schematic, and are not illustrated based on actual scales. Relative dimensions and proportions of parts illustrated in the drawings are exaggerated or reduced in size for the purpose of clarity and convenience in the drawings, and any dimension is just illustrative but not restrictive. Further, the same reference numerals designate the same structures, elements or components illustrated in two or more drawings in order to exhibit similar characteristics. 
     Exemplary embodiments of the present invention illustrate ideal exemplary embodiments in more detail. As a result, various modifications of the drawings are expected. Therefore, the exemplary embodiments are not limited to specific forms in regions illustrated in the drawings, and for example, include modifications of forms by the manufacture. 
     Hereinafter, a free rotary fluid machine according to an exemplary embodiment of the present invention will be described with reference to the accompanying drawings. 
       FIG. 1  is a perspective view illustrating a rotary fluid machine according to an exemplary embodiment of the present invention,  FIG. 2  is a perspective view illustrating a tip seal illustrated in  FIG. 1 ,  FIG. 3  is a perspective view illustrating a blade illustrated in  FIG. 1 ,  FIG. 4  is a view for explaining a case in which the rotary fluid machine according to the exemplary embodiment of the present invention is a turbine,  FIG. 5  is a view for explaining a case in which the rotary fluid machine according to the exemplary embodiment of the present invention is a compressor, and  FIG. 6  is a view for explaining a case in which the rotary fluid machine according to the exemplary embodiment of the present invention is a compander. 
     As illustrated in  FIGS. 1 to 3 , a free rotary fluid machine  100  according to an exemplary embodiment of the present invention may include: a main body  110  which is provided in a cylindrical shape and has a circular outer circumferential surface and an elliptical inner circumferential surface; a rotor  200  which is provided in the main body  110 , has an approximately quadrangular cross section, and rotates about the same rotation center as the main body  110 ; tip seals  300  which are provided at one side of the rotor  200 ; auxiliary tip seals  310  each of which is formed at one end of the tip seal  300  and improves contact performance between the rotor  200  and the tip seal  300 ; and blades  400  which are provided between the tip seals  300  provided adjacent to each other. 
     Since the auxiliary tip seals  310  are formed as described above, friction between the main body  110  and the tip seals  300  is reduced, spaces formed among the main body  110 , the blades  400 , and the tip seals  300  are sealed, thereby preventing a leak of an introduced working fluid. 
     The free rotary fluid machine  100  according to the exemplary embodiment of the present invention may include the main body  110 , the rotor  200 , the tip seals  300 , the blades  400 , and the auxiliary tip seals  310 . 
     The rotor  200 , the tip seals  300 , and the blades  400  may be accommodated in the main body  110 . The main body  110  may be provided in a hollow cylindrical shape having a space formed therein, and the main body  110  according to the exemplary embodiment of the present invention has the outer circumferential surface which is formed in a circular shape, and the inner circumferential surface which is formed in an approximately elliptical shape different from the shape of the outer circumferential surface. However, in some instances, the outer circumferential surface of the main body, as well as the inner circumferential surface of the main body  110 , may also be formed in the same elliptical shape. 
     The reason why the inner circumferential surface of the main body  110  is formed in an elliptical is to change volumes of operation spaces  112  for compressing or expanding a working fluid when the working fluid, which is introduced from intake ports  120  and  122  to be described below, is compressed or expanded to convert fluid energy into mechanical energy. 
     As described above, the main body  110  may have the intake ports through which the working fluid is introduced into the operation spaces  112 , and exhaust ports through which the working fluid is discharged from the operation spaces. Specifically, at least one intake ports and at least one exhaust port may be provided in the main body  110 . 
     As illustrated in  FIG. 1 , the main body  110  of the free rotary fluid machine  100  according to the exemplary embodiment of the present invention may have two intake ports  120  and  122  and two exhaust ports  130  and  132 . 
     In this case, the intake ports  120  and  122  and the exhaust ports  130  and  132  may be provided radially based on a rotation center of the main body  110 . The reason why the intake ports  120  and  122  and the exhaust ports  130  and  132  are provided radially is to improve an output of energy or pressure produced when the working fluid is introduced. In addition, in some instances, positions of the intake ports  120  and  122  and the exhaust ports  130  and  132  illustrated in  FIG. 1  may vary in accordance with a rotation direction of the rotor  200  or a position or a size of the operation space  112  of the main body  110 . 
     The rotor  200  may be provided in the main body  110  formed in an elliptical shape. The rotor  200  may be formed in a hexahedral shape having an approximately quadrangular cross section. In a case in which the rotor  200  is formed to have a quadrangular cross section, it is possible to reduce costs required to process the rotor  200 . In addition, rotational force of the rotor  200  is not greatly affected even though the rotor  200  is formed to have an approximately quadrangular cross section. 
     The rotor  200  may have a rotating shaft  202  which is a rotation center that coincides with a center of the main body  110 . Although not illustrated in the drawings, the rotating shaft  202  of the rotor  200  may be coupled to a cover (not illustrated) coupled to one side of the main body  110 . 
     The rotor  200  is a member which is rotated in the main body  110  and on which the tip seals  300  and the blades  400 , which will be described below, are mounted. 
     The tip seal  300  may be provided at one side of the rotor  200 . Particularly, the tip seal  300  may be mounted at an edge portion of the rotor  200 . 
     Specifically, one end portion  302  of the tip seal  300  in a longitudinal direction of the tip seal  300  may be formed in a cylindrical shape having a circular cross section, and the other end portion  304  of the tip seal  300  may be formed in a hexahedral bar shape having a quadrangular cross section. The other end portion  304  of the tip seal  300 , which is formed as described above, may be coupled to a groove  204  formed at an edge portion of the rotor  200 . Since the rotor  200  has a hexahedral shape having a quadrangular cross section as described above, the tip seals  300  may be provided at four edges of the quadrangular cross section of the rotor  200 , one for each edge. 
     When the rotor  200  is rotated in the main body  110 , centrifugal force is applied to the tip seal  300 . When the centrifugal force is applied to the tip seal  300 , the tip seal  300  is moved in the groove  204  formed at the edge of the quadrangular cross section of the rotor  200 . That is, the cylindrical one end portion  302  of the tip seal  300  is moved toward an inner circumferential surface of the main body  110 . When the cylindrical one end portion  302  of the tip seal  300  is moved toward the inner circumferential surface of the main body  110  by the centrifugal force as described above, one end portion  302  of the tip seal  300  may always be maintained in a state of being in contact with the inner circumferential surface of the main body  110 , and as a result, it is possible to prevent the working fluid from leaking from the operation space  112 . 
     Meanwhile, a pressing member  210  may be further provided between the rotor  200  and the tip seal  300 . 
     The pressing member  210  may press the tip seal  300  toward the inner circumferential surface of the main body  110  when the rotor  200  is rotated, so that one end portion  302  of the tip seal  300  comes into contact with the inner circumferential surface of the main body  110 . In addition, when the tip seal  300  is moved in a state of being in contact with the inner circumferential surface of the main body  110  having an elliptical shape, the tip seal  300  may elastically support the retraction of the rotor  200  toward the rotation center while moving from an inner circumferential surface of a long-radius portion of the ellipse to an inner circumferential surface of a short-radius portion of the ellipse. 
     The pressing member  210  according to the exemplary embodiment of the present invention may be formed in the form of a spring which has elasticity and may press the tip seal  300  against the inner circumferential surface of the main body  110 , and various springs such as a coil spring, a compressive spring, and a flat spring may be applied as necessary. 
     However, the pressing member  210  is not always required, and the pressing member  210  may be omitted as long as the rotor  200  may be rotated in a state in which the blade  400  moves toward the inner circumferential surface of the main body  110  and thus the tip seal  300  is always maintained in a state of being in contact with the inner circumferential surface of the main body  110 . 
     Meanwhile, the auxiliary tip seal  310  may be provided at the cylindrical one end portion  302  of the tip seal  300 . The auxiliary tip seal  310  is provided to protrude from the cylindrical one end portion  302  of the tip seal  300  to the inner circumferential surface of the main body  110 , thereby improving contact performance between the rotor  200  and the tip seal  300  or increasing an contact area between the rotor  200  and the tip seal  300 . 
     Specifically, as illustrated in  FIG. 2 , the auxiliary tip seal  310  may include a sealing member  314 , and an elastic support body  316  which pushes the sealing member  314  toward the inner circumferential surface of the main body  110  or supports the sealing member  314  when the sealing member  314  is retracted. The sealing member  314  may be drawn in (retracted into) or pulled out (drawn) from an opening  312  formed in the cylindrical one end portion  302  of the tip seal  300 . 
     The sealing member  314  may be formed in the form of a thin plate, and the sealing member  314  according to the exemplary embodiment of the present invention may be made of a ceramic material. However, the material of the sealing member  314  may be changed as necessary as long as the material is not likely to increase friction with the inner circumferential surface of the main body  110  or damage the inner circumferential surface of the main body  110 . 
     The elastic support body  316  may elastically support the sealing member  314 . 
     Specifically, one end portion of the elastic support body  316  is coupled to and supports a lower end surface of the sealing member  314 , and the other end portion of the elastic support body  316  may be coupled to the opening  312  of the tip seal  310 . Therefore, the elastic support body  316  may enable the sealing member  314  to be drawn in (retracted into) or pulled out (drawn) from the opening  312 . The elastic support body  316  according to the exemplary embodiment of the present invention may be formed in the form of a spring having elasticity, and various springs such as a flat spring and a coil spring may be applied as necessary. 
     Meanwhile, a width of the sealing member  314  is smaller than a width of the opening  312  considering that the inner circumferential surface of the main body  110  having an elliptical shape, such that the sealing member  314  is slightly moved in the rotation direction along a curvature of the inner circumferential surface, and as a result, a tip portion of the sealing member  314  may always be maintained in a state of being in contact with the inner circumferential surface of the main body  110 . 
     The operation space  112  is formed by the inner circumferential surface of the main body  110 , the tip seal  300 , and the blade  400 , and the operation space  112  is a space of which the size or the volume varies. To this end, the blade  400  may be positioned between the tip seals  300 . 
     The blades  400  are provided between the tip seals  300  provided at the four points of the rotor  200 , and both ends of the blade  400  may be supported by the tip seals  300 . In this case, both ends of the blade  400  are formed in the form of a curved surface so that the blade  400  are in surface-to-surface contact with the cylindrical one end portion  302  of the tip seal  300 , and as a result, it is possible to stably maintain surface-to-surface contact or coupling between the tip seals  300  and the blade  400 . 
     As illustrated in  FIG. 3 , the blade  400  may be formed in a shape having an inverted trapezoidal cross section. One end surface  402  and the other end surface  404  of the blade  400  in a thickness direction of the blade  400 , that is, an upper surface and a lower surface of the blade  400  are different in length from each other. 
     A length of one end surface  402  of the blade  400  according to the exemplary embodiment of the present invention may be longer than a length of the other end surface  404 . 
     The reason is that tip seal contact portions  403  between one end surface  402  and the other end surface  404  in the thickness direction of the blade  400  need to be formed in the form of a curved surface because both ends of the blade  400  are fitted between the two neighboring tip seals  300  while being in surface-to-surface contact with the cylindrical one end portion  302  of the tip seal  300 , and in this case, a curvature of the curved surface of the tip seal contact portion  403 , which connects one end surface  402  and the other end surface  404 , may be equal to a curvature of the cylindrical one end portion  302  of the tip seal  300 . 
     In addition, a portion where the tip seal contact portion  403  meets one end surface  402  of the blade  400  is positioned at an upper end portion of the cylindrical one end portion  302  of the tip seal  300 , and this portion may be formed to be rounded, that is, formed to have a predetermined radius of curvature instead of being formed to be angled. 
     Therefore, it is possible to prevent the blade  400  or the tip seal  300  from being damaged as the blade  400  is stuck into the cylindrical one end portion  302  of the tip seal  300  or causes friction due to the portion where the tip seal contact portion  403  meets one end surface  402  of the blade  400  when the tip seal contact portion  403  of the blade  400  is rotated in the inner circumferential surface of the main body  110 . 
     Specifically, in a case in which the portion where the one end surface  402  of the blade  400  meets the tip seal contact portion  403  is formed to be exactly matched with the cylindrical one end portion  302  of the tip seal  300 , the blade  400  may be more stably supported by the tip seal  300 . 
     Meanwhile, both ends of the blade  400  in the longitudinal direction of the blade  400 , that is, the tip seal contact portions  403  may be formed, if possible, to have a large contact area with the cylindrical one end portion  302  of the tip seal  300  or have a long length. Referring to  FIG. 1 , it can be seen that the tip seal contact portion  403  is in contact with the tip seal  300  from a point at which the cylindrical one end portion  302  of the tip seal  300  meets the other end portion  304  of the tip seal  300 . 
     That is, according to the blade  400  of the free rotary fluid machine  100  according to the exemplary embodiment of the present invention, to increase a contact area in which the tip seal contact portion  403  and the tip seal  300  are in direct contact with each other, one end surface  402  and the other end surface  404  of the blade  400  are formed in the form of a curved surface, and centers of radii of curvature of one end surface  402  and the other end surface  404  of the blade  400  are positioned at the same side based on the blade  400 . With the aforementioned configuration, when the blade  400  is moved toward the inner circumferential surface of the main body  110  as the rotor  200  is rotated at a high speed, the tip seals  300 , which are in contact with and support both ends of the blade  400  while maintaining the surface-to-surface contact state between the blade  400  and the tip seals  300 , are also moved toward the inner circumferential surface of the main body  110 , such that the tip seals  300  may be in close contact with the inner circumferential surface of the main body  110 , and as a result, it is possible to prevent a leak caused by destruction of the surface-to-surface contact state between the tip seals  300  and both ends of the blade  400 , and thus to prevent the situation in which the blade  400  cannot be rotated. 
     An operation of the free rotary fluid machine  100  according to the exemplary embodiment of the present invention, which has the aforementioned structures, will be described with reference to  FIGS. 4 to 6 . 
     Here, the free rotary fluid machine  100  according to the exemplary embodiment of the present invention may be applied as various forms such as a turbine, a compressor, a pump, an engine, and a compander (a combination of a compressor and an expander). 
     Assuming that the rotor  200  of the free rotary fluid machine  100  according to the present invention is rotated counterclockwise as illustrated in  FIGS. 4 to 6 , reference numerals  120  and  122  indicate the intake ports, and reference numerals  130  and  132  indicate the exhaust ports. 
     In this case, as illustrated in  FIG. 4 , if the free rotary fluid machine  100  according to the exemplary embodiment of the present invention is a turbine, the intake ports  120  and  122  may be formed at positions at which the tip seal  300  and the auxiliary tip seal  310  are in close contact with the inner circumferential surface of the main body  110 , and the exhaust ports  130  and  132  may be formed at positions at which the operation space  112  formed between the inner circumferential surface of the main body  110  and the rotor  200  has a largest volume. 
     As the free rotary fluid machine  100  operates as a turbine in accordance with the positions of the intake ports  120  and  122  and the exhaust ports  130  and  132 , a working fluid such as steam, air, and gas may be introduced through the intake ports  120  and  122 . Then, the introduced working fluid rotates the rotor  200  while pushing the tip seal  300  and the blade  400 , the working fluid is expanded in a large space so as to expand a volume of the operation space  12 , and then the working fluid may be discharged through the exhaust ports  130  and  132 . 
     Meanwhile, as illustrated in  FIG. 5 , if the free rotary fluid machine  100  according to the exemplary embodiment of the present invention is a compressor, the intake ports  120  and  122  through which a working fluid is introduced may be formed at positions at which the operation space  112  formed between the inner circumferential surface of the main body  110  and the rotor  200  has a largest volume, and the exhaust ports  130  and  132  through which the working fluid is discharged may be formed at positions adjacent to positions at which the tip seal  300  and the auxiliary tip seal  310  are in contact with the inner circumferential surface of the main body  110 . 
     As the free rotary fluid  110  operates as a compressor in accordance with the positions of the intake ports  120  and  122  and the exhaust ports  130  and  132 , the operation space  112  formed between the main body  110  and the rotor is filled with the working fluid, and the working fluid is compressed when the rotor  200  is rotated and thus a volume of the operation space  112  formed between the main body  11  and the rotor  200  is decreased. The compressed working fluid may be discharged through the exhaust ports  130  and  132 . 
     That is, in a case in which the free rotary fluid machine  100  is a compressor, the positions of the intake ports  120  and  122  and the exhaust ports  130  and  132  may be different from the positions of the intake ports and the exhaust ports in a case in which the free rotary fluid machine  100  is a turbine. 
     As illustrated in  FIG. 6 , the free rotary fluid machine  100  according to the exemplary embodiment of the present invention may operate as a compander. Here, the compander refers to a single free rotary fluid machine  100  that performs operations of a compressor and an expander. 
     In a case in which the free rotary fluid machine  100  is a compander, the intake ports  120  and  122  may be formed at a position at which the tip seal  300  and the auxiliary tip seal  310  are in close contact with the inner circumferential surface of the main body  110  and at a position at which the operation space  112  formed between the inner circumferential surface of the main body  110  and the rotor  200  has a largest volume, respectively, and the exhaust ports  130  and  132 , through which the working fluid is discharged, may be formed at a position at which the operation space  112  formed between the inner circumferential surface of the main body  110  and the rotor  200  has a largest volume and at a position adjacent to a position at which the tip seal  300  and the auxiliary tip seal  310  are in contact with the inner circumferential surface of the main body  110 . 
     As the free rotary fluid machine  100  operates as a compander in accordance with the positions of the intake ports  120  and  122  and the exhaust ports  130  and  132 , the operation space  112  formed between the main body  110  and the rotor  200  is filled with the working fluid introduced through the intake port  120 , and the working fluid may be compressed when the rotor  200  is rotated and thus a volume of the operation space  112  formed between the main body  110  and the rotor  200  is decreased. The compressed working fluid is discharged through the exhaust port  132 . In addition, the working fluid introduced through the intake port  122  rotates the rotor  200  while pushing the tip seal  300  and the blade  400 , the working fluid is expanded in a large space so as to expand a volume of the operation space  112 , and then the working fluid may be discharged through the exhaust port  130 . 
     Here, frictional force, which may occur between the main body  110  and the rotor  200 , is reduced by the tip seal  300  and the auxiliary tip seal  310  formed in the tip seal  300 , and as a result, it is possible to increase rotational force of the rotor  200  and improve sealing performance between the inner circumferential surface of the main body  110  and the tip seal  300  or the auxiliary tip seal  310 . 
     As described above, according to the free rotary fluid machine  100  according to the present invention, the auxiliary tip seal  310  is formed to protrude from the tip seal  300 , such that contact performance or sealing performance between the inner circumferential surface of the main body  110  and the tip seal  300  is improved when the rotor  200  is rotated, and as a result, it is possible to seal the operation space  112  formed among the inner circumferential surface of the main body  110 , the rotor  200 , and the tip seal  300 . 
     In addition, according to the exemplary embodiments of the present invention, the operation space  112  formed among the inner circumferential surface of the main body  110 , the rotor  200 , and the tip seal  300  is sealed by the auxiliary tip seal  310 , and as a result, it is possible to reduce friction between the tip seal  300  and the main body  110  and to prevent a leak of the introduced working fluid. 
     In addition, according to the exemplary embodiments of the present invention, since the auxiliary tip seal  310  is drawn in (retracted into) and pulled out (drawn) from the tip seal  300 , the tip seals  300  may be moved in a state in which both ends of the blade  400 , which are supported between the tip seals  300  provided adjacent to each other, that is, the tip seal contact portions  403  are maintained in a state of being in surface-to-surface contact with the tip seals  300 . 
     In addition, according to the exemplary embodiments of the present invention, the pressing member  210  is provided between the tip seal  300  and the rotor  200 , and as a result, it is possible to maintain a state in which the tip seal  300  is pressed against the inner circumferential surface of the main body  110 , and it is possible to elastically support the tip seal  300  when the tip seal  300  is retracted toward the rotating shaft  202  of the rotor  200 . 
     While the exemplary embodiments of the present invention have been described with reference to the accompanying drawings, those skilled in the art will understand that the present invention may be implemented in any other specific form without changing the technical spirit or an essential feature thereof. 
     Accordingly, it should be understood that the aforementioned exemplary embodiments are described for illustration in all aspects and are not limited, and the scope of the present invention shall be represented by the claims to be described below, and it should be construed that all of the changes or modified forms induced from the meaning and the scope of the claims, and an equivalent concept thereto are included in the scope of the present invention. 
     INDUSTRIAL APPLICABILITY 
     The present invention may be applied to a fluid machine, a free rotary fluid machine, and the like.