Abstract:
A reciprocating compressor, wherein a flange unit connected to the mover constituting the reciprocating motor is installed on the piston constituting the compressing unit, the distance between the piston flange unit and the front frame of the frame unit is shorter than that of the between the piston flange unit and the reciprocating motor. In the process of being transmitted the linear reciprocal movement driving force of the reciprocating motor and compressing the gas in the compressing unit, the stability of the compressor is raised by preventing the components moving together with the mover of reciprocating motor from impacting with other components by the displacement generated by compression force applying the piston constituting the compressing unit. Also, the size of compressor can be scaled down by compactly constituting the components.

Description:
This application is the national phase under 35 U.S.C. § 371 of PCT International Application No. PCT/KR01/00870 which has an International filing date of May 24, 2001, which designated the United States of America. 

   TECHNICAL FIELD 
   The present invention relates to a reciprocating compressor, and in particular to a reciprocating compressor which is capable of constructing construction parts compactly, restraining collision noise occurrence by preventing collision of the construction parts in operation and stabilizing the operation. 
   BACKGROUND ART 
   Generally, a compressor is for compressing a fluid. The compressor can be divided into a rotation compressor, a reciprocating compressor and a scroll compressor, etc. according to fluid compression types. 
   In the rotation compressor, a rotational shaft rotates by receiving a driving force of a rotational motor, simultaneously an eccentric part combined with the rotational shaft performs an eccentric rotation in a cylindrical compression space of a cylinder, and accordingly gas is compressed. 
   In the scroll compressor, a rotational shaft rotates by receiving a driving force of a rotational motor, simultaneously a rotary scroll combined with the rotational shaft engaging with a fixed scroll performs a rotating motion, and accordingly gas is compressed. 
   In the reciprocating compressor, a rotational shaft rotates by receiving a driving force of a rotational motor, simultaneously a connecting rod combined with the rotational shaft converts the rotating motion into a linear reciprocating motion and transmits it to a piston, the piston performs the linear reciprocating motion in a cylinder, and accordingly gas is compressed. 
   In addition, in another type of the reciprocating compressor, a piston receiving a driving force of a reciprocating motor performs a linear reciprocating motion in a cylinder, and accordingly gas is compressed. 
     FIG. 1  illustrates a reciprocating compressor in accordance with the conventional art. As depicted in  FIG. 1 , the reciprocating compressor includes a container  100  having a suction pipe  10  in which gas is sucked; a frame unit installed inside the container  100 ; a reciprocating motor installed at the frame unit and generating a linear reciprocating driving force; a compression unit installed at the frame unit with a certain distance from the reciprocating motor, receiving the driving force of the reciprocating motor and compressing gas; a spring unit for elastically supporting the linear reciprocating driving force of the reciprocating motor; and a valve unit installed at the compression unit and opening/closing a compression space in which gas is compressed. 
   The container  100  is sealed to have a certain inner space, and the suction pipe  10  penetrates-combines with the container  100  so as to communicate with the container  100 . 
   The reciprocating motor consists of an outer stator  310  installed at a rear frame  210  of the frame unit; an inner stator  320  inserted into the outer stator  310  with a certain interval; a wound coil  330  inserted into an open groove  311  formed at the outer stator  310 ; and a mover  340  inserted between the outer stator  310  and the inner stator  320  to perform a linear reciprocating motion. 
   And, a middle frame  220  is fixedly combined with a certain side of the reciprocating motor to face the rear frame  210 . 
   The compression unit includes a cylinder  410  combined with a front frame  230  having a certain distance from the reciprocating motor and a piston  420  inserted into a compression space  411  of the cylinder  410  and connected to the mover  340  of the reciprocating motor. 
   And, in the front frame  230 , a protrusive supporting portion  232  extended from a certain side of a plate portion  231  is formed so as to have a certain length, and a through hole  233  in which the cylinder  410  is inserted is formed at the supporting portion  232 . 
   In the cylinder  410 , the compression space  411  penetrates through a cylinder body  412  having a certain length. And, the cylinder  410  is inserted into the through hole  233  of the front frame  230 . 
   Herein, the end surface of the supporting portion  232  of the front frame  230  is the same surface as the end surface of the cylinder body  412 . 
   The piston  420  includes a body unit  421  having a certain length and a flange portion  422  extended from a certain side of the body unit  421  so as to have a certain size and connected to the mover  340 . 
   In the piston  420 , the flange portion  422  is combined with the mover  340 , and the body unit  421  is inserted into he compression space  411  of the cylinder  410 . 
   The spring unit includes a certain-shaped spring supporting portion  510  in which a certain side is combined with the flange portion  422  of the piston  420  or the mover  340  so as to place between the front frame  230  and the middle frame  220 ; and a spring  520  respectively placed at both sides of the spring supporting portion  510 . 
   The valve unit includes a discharge cover  610  combined with the front frame  230  to cover the compression space  411  of the cylinder; a discharge valve  620  placed inside the discharge cover  610  and opening/closing the compression space  411  of the cylinder  410 ; a valve spring  630  for elastically supporting the discharge valve  620 ; and a suction valve  640  combined with the end of the piston  420  and opening/closing a suction channel  423  formed inside the piston  420 . 
   Unexplained reference numeral  20  is a discharge pipe,  240  is a connecting member of the frame unit, and  341  is a permanent magnet. 
   The operation of the conventional reciprocating compressor will be described. 
   When power is applied to the reciprocating motor, a current flows onto the wound coil  330  of the reciprocating motor, a flux is formed between the outer stator  310  and the inner stator  320 , by mutual operation of the flux between the outer stator  310  and the inner stator  320  with a flux by the permanent magnet  341  of the mover  340 , the mover  340  performs a linear reciprocating motion. 
   The linear reciprocating driving force of the mover  340  is transmitted to the piston  420 , and the piston  420  performs a linear reciprocating motion inside the cylinder compression space  411 . 
   The spring unit stores, discharges the linear reciprocating power of the reciprocating motor as elastic energy and causes a resonance motion. 
   With the linear reciprocating motion of the piston  420  in the compression space  411  of the cylinder  410 , the valve unit is operated, the gas sucked into the suction pipe  10  is sucked into the compression space  411  through the suction channel  423  of the piston  420 , compressed discharged, herein, the gas is discharged to the outside through the discharge pipe  20  of the discharge cover  610 . 
   In general, the compressor includes a cooling cycle apparatus and is installed to an air-conditioner, a refrigerator and a showcase, etc. In order to install the compressor to a system such as an air-conditioner, a refrigerator and a showcase, etc., the compressor has to have a simple structure and require a small installation space and operate stably. 
   In the meantime, unlike other compressors, in the reciprocating compressor, an output of the reciprocating motor as a driving power source is a linear reciprocating motion power, the piston  420  receives the linear reciprocating motion power of the reciprocating motor and performs the linear reciprocating motion in the compression space  411  to compress the gas, and accordingly constructing parts moving in the axial direction compactly is important object to simplify a structure of the compressor. 
   In the meantime, as depicted in  FIG. 2 , in a reciprocating compressor constructed by considering the above-mentioned object, in the linear reciprocating motion of the flange portion  422  of the piston (receiving the driving force of the reciprocating motor and performing the linear reciprocating motion in the compression space  411  of the cylinder), a distance between the inner stator  320  of the reciprocating motor respectively placed at both sides of the flange portion  422  and the front frame  230  corresponds to a reciprocating motion distance of the flange portion  422 . 
   And, the flange portion  422  of the piston  420  is placed between the inner stator  320  and the front frame  230 , a distance (a) between the end surface of the front frame  230  and the flange portion  422  is the same as a distance (b) between the inner stator  320  and the flange portion  422 . 
   And, as depicted in  FIG. 3 , in the cylinder  410  in which the piston  420  is inserted and the front frame  230  of the frame unit in which the cylinder  410  is inserted, the end surface (c) of the cylinder  410  is placed on the same surface as the end surface (d) of the supporting portion  232 . 
   In the above-mentioned construction, the piston  420  receives the linear reciprocating driving force of the reciprocating motor, sucks, compresses and discharges the gas while performing the linear reciprocating motion in the compression space  411  of the cylinder  410 , however, by the compressed gas force in the compression space  411 , the center of the reciprocating motion of the piston  420  may be moved from an initial position toward the reciprocating motor, due to that, the flange portion  422  of the piston  420  may collide against the inner stator  320  of the reciprocating motor during the linear reciprocating motion, and accordingly collision noise may occur and the operation may be unstable. 
   In addition, when the piston  420  performs the unstable reciprocating motion, the flange portion  422  of the piston  420  may collide against the end surface (d) of the supporting portion  232  of the front frame  230  and the end surface (C) of the piston  420 , impact may be applied to the piston  420  and the front frame  230 , and accordingly the assembly condition of the valve unit connected to the cylinder  410  may not be secured. 
   TECHNICAL GIST OF THE PRESENT INVENTION 
   In order to solve the above-described problems, it is an object of the present invention to provide a reciprocating compressor which is capable of constructing construction parts compactly, restraining collision noise occurrence by preventing collision between the construction parts in operation and stabilizing the operation. 
   In order to achieve the above-mentioned object, in a reciprocating compressor comprising a container having a suction pipe in which gas is sucked; a frame unit installed inside the container; a reciprocating motor installed at the frame unit and generating a linear reciprocating driving force; a compression unit installed at the frame unit so as to have a certain distance from the reciprocating motor, receiving the driving force of the reciprocating motor and compressing gas; a spring unit for elastically supporting the linear reciprocating driving force of the reciprocating motor; and a valve unit installed at the compression unit and opening/closing the compression space in which gas is compressed, wherein the piston of the compression unit has a flange portion connected to a mover of the reciprocating motor, a distance (k) between a front frame of the frame unit and the flange portion of the piston is smaller than a distance (m) between the reciprocating motor and the flange portion of the piston. 

   
     BRIEF DESCRIPTION OF DRAWINGS 
     The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention. 
     In the drawings: 
       FIG. 1  illustrates a reciprocating compressor in accordance with the conventional art; 
       FIG. 2  is a sectional view illustrating major parts of the reciprocating compressor; 
       FIG. 3  is a sectional view illustrating major parts of the reciprocating compressor; 
       FIG. 4  is a sectional illustrating a reciprocating compressor in accordance with the present invention; 
       FIG. 5  is a sectional view illustrating major parts of the reciprocating compressor in accordance with the present invention; 
       FIG. 6  is a sectional view illustrating major parts of the reciprocating compressor in accordance with the present invention; 
       FIG. 7  is a sectional view illustrating major parts of the reciprocating compressor in accordance with the present invention; 
       FIG. 8  is a sectional view illustrating major parts of the reciprocating compressor in accordance with the present invention; 
       FIG. 9  is a sectional view illustrating major parts of the reciprocating compressor in accordance with the present invention; and 
       FIG. 10  is a sectional view illustrating major parts of the reciprocating compressor in accordance with the present invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Hereinafter, the preferred embodiment of the present invention will be described with reference to accompanying drawings. 
   As depicted in  FIG. 4 , a reciprocating compressor in accordance with the present invention includes a container having a suction pipe in which gas is sucked; a frame unit installed inside the container; a reciprocating motor installed at the frame unit and generating a linear reciprocating driving force; a compression unit installed at the frame unit so as to have a certain distance from the reciprocating motor, receiving the driving force of the reciprocating motor and compressing gas; a spring unit for elastically supporting the linear reciprocating driving force of the reciprocating motor; and a valve unit installed at the compression unit and opening/closing the compression space in which gas is compressed. 
   The container  100  is sealed to have a certain inner space, and the suction pipe  10  penetrates-combines with the container  100  so as to communicate with the container  100 . 
   The compression unit includes a cylinder  410  combined with a front frame  230  having a certain distance from the reciprocating motor and a piston  420  inserted into a compression space  411  of the cylinder  410  and connected to the mover  340  of the reciprocating motor. 
   And, in the front frame  230 , a protrusive supporting portion  232  extended from a certain side of a plate portion  231  is formed so as to have a certain length, and a through hole  233  in which the cylinder  410  is inserted is formed at the supporting portion  232 . 
   And, the supporting portion  232  of the front frame  230  is projected toward the reciprocating motor. 
   In the cylinder  410 , the compression space  411  penetrates through a cylinder body  412  having a certain length. And, the cylinder  410  is inserted into the through hole  233  of the front frame  230 . 
   As depicted in  FIG. 5 , when the cylinder  410  is inserted into the through hole  233  of the front frame  230 , the end of the cylinder  410  is placed inside the through hole  233  of the supporting portion  232  of the front frame  230 . 
   In more detail, the end surface (d) of the supporting portion  232  of the front frame  230  is combined with the end surface (c) of the cylinder  410  as a step structure to make a distance (k) between the flange portion  422  of the piston  420  and the end surface (d) of the supporting portion  232  shorter than a distance (f) between the flange portion  422  of the piston  420  and the end surface (c) of the cylinder  410 . 
   The piston  420  includes a body unit  421  having a certain length; and a flange portion  422  extended from a certain side of the body unit  421  so as to have a certain size and connected to the mover  340 . 
   The reciprocating motor consists of an outer stator  310  installed at a rear frame  210  of the frame unit; an inner stator  320  inserted into the outer stator  310  with a certain interval; a wound coil  330  inserted into an open groove  311  formed at the outer stator  310 ; and a mover  340  inserted between the outer stator  310  and the inner stator  320  so as to perform a linear reciprocating motion. 
   When a current flows onto the wound coil  330 , the outer stator  310  and the inner stator  320  form a closed loop in which a flux flows, herein, both sides of the open groove  311  of the outer stator  310  are pole portions  312  respectively forming each pole. 
   As depicted in  FIG. 6 , the mover  340  includes a permanent magnet  341  having a certain length. The permanent magnet  341  has the same length as an added length of an inlet length (g) of the open groove  311  and the one pole portion length (h), places along the both pole portions  312  of the outer stator  310  and faces the open groove  311 . In addition, the center of the permanent magnet  341  and the open groove  311  are eccentric. 
   In more detail, on the basis of the center of the open groove  311 , the center of the permanent magnet  341  is placed so as to be eccentric as a certain amount toward the compression unit. 
   And, a middle frame  220  is fixedly combined with the reciprocating motor to combine the outer stator  310  of the reciprocating motor with the rear frame  210 . 
   In more detail, the middle frame  220  is placed between the front frame  230  and the rear frame  210 . 
   And, the frame unit includes the front, middle and rear frames  230 ,  220 ,  210  and a connecting member  240  placed between the front and middle frames  230 ,  220 . 
   The mover  340  of the reciprocating motor is connected to the flange portion  422  of the piston  420  constructing the compression unit. 
   As depicted in  FIG. 7 , the flange portion  422  of the piston  420  is placed between the front frame  230  and the reciprocating motor, a distance (k) between the flange portion  422  and the front frame  230  is smaller than a distance (m) between the flange portion  422  and the reciprocating motor. 
   In more detail, the distance (k) between the end surface (d) of the supporting portion  232  and one side of the reciprocating motor facing the flange portion  422  is smaller than the distance (m) between the inner stator  320  of the reciprocating motor and the flange portion  422 . 
   As depicted in  FIG. 8 , the distance (m) between the flange portion  422  and the one side of the reciprocating motor facing the flange portion  422  is smaller than a distance (p) between the end surface (n) of the mover  34   b  and the rear frame  210  facing the end surface (n). 
   As depicted in  FIG. 9 , the height of the pole portion  312  is smaller than an added distance ((k)+(m)) of the distance (k) between the end surface (d) of the supporting portion  232  and the flange portion  422  and the distance (m) between the flange portion  422  and the reciprocating motor facing the flange portion  422 . 
   The spring unit includes a certain-shaped spring supporting portion  510  in which a certain side is combined with the flange portion  422  of the piston  420  or the mover  340  so as to lie between the front frame  230  and the middle frame  220 ; and a spring  520  respectively placed at both sides of the spring supporting portion  510 . 
   The valve unit includes a discharge cover  610  combined with the front frame  230  to cover the compression space  411  of the cylinder; a discharge valve  620  placed inside the discharge cover  610  and opening/closing the compression space  411  of the cylinder  410 ; a valve spring  630  for elastically supporting the discharge valve  620 ; and a suction valve  640  combined with the end of the piston  420  and opening/closing a suction channel  423  formed inside the piston  420 . 
   And, as depicted in  FIG. 10 , a distance (r) between the discharge valve  620  and the end of the piston  420  (the suction valve  640  combined with the end of the piston  420 ) is smaller than a distance (k) between the end surface (d) of the supporting portion  232  and the flange portion  422  of the piston  420 . 
   Hereinafter, advantages of the reciprocating compressor in accordance with the present invention will be described. 
   When power is applied to the reciprocating motor, a current flows onto the wound coil  330  of the reciprocating motor, a flux is formed between the outer stator  310  and the inner stator  320 , by mutual operation of the flux between the outer stator  310  and the inner stator  320  with a flux by the permanent magnet  341  of the mover  340 , the mover  340  performs a linear reciprocating motion. 
   Herein, a reciprocating motion distance of the mover  340  is determined by the permanent magnet  341  and the outer stator  310  of the mover  340 . In more detail, a length of the permanent magnet  341  is the same as the added length ((h)+(g)) of a length (h) of the pole  312  and an inlet length (g) of the open groove  311 , the permanent magnet  341  is moved by the mutual operation of the flux formed on the inner and outer stators  310 ,  320  according to the current flowing onto the wound coil  330 , the reciprocating distance of the permanent magnet  341  is the length (h) of the pole portion  312  of the outer stator  310 , and accordingly the end of the permanent magnet  341  does not escape from the end of the pole portion  312  in the linear reciprocating motion. 
   And, the linear reciprocating driving force of the mover  340  is transmitted to the piston  420  combined with the mover  340 , the piston  420  performs a linear reciprocating motion in the compression space  411 . 
   Herein, the flange portion  422  of the piston  420  connected to the mover  340  performs a reciprocating motion between the end surface (d) of the supporting portion  232  (of the front frame  230 ) and the inner stator  320  of the reciprocating motor. 
   The spring unit stores, discharges the linear reciprocating force of the reciprocating motor as elastic energy and causes a resonance motion. 
   With the linear reciprocating motion of the piston  420  in the compression space  411  of the cylinder  410 , the valve unit is operated, the gas sucked into the suction pipe  10  is sucked into the compression space  411  through the suction channel  423  of the piston  420 , compressed discharged, herein, the gas is discharged to the outside through the discharge pipe  20  of the discharge cover  610 . 
   In more detail, when the piston  420  is moved to the bottom dead center, the suction valve  620  is curved due to a pressure difference between the compression space  411  and the outside, the suction valve  423  is open, and accordingly the gas of the suction pipe  10  is sucked into the compression space  411  through the suction channel  423 . 
   And, when the piston  420  is moved from the bottom dead center to the upper dead center, the suction valve  620  closes the suction channel  423 , the gas of the compression space  411  of the cylinder  410  is compressed and reaches a set pressure state, the discharge valve  620  of the valve unit is open, and accordingly the compressed gas is discharged. 
   As described above, the piston  420  compresses the gas by performing the reciprocating motion in the compression space  411  of the cylinder  410 . 
   While the piston  420  compresses the gas by moving between the bottom dead center and the upper dead center by the driving force of the reciprocating motor, the pressure force of the gas acts on the piston  420 . 
   In the present invention, because the flange portion  422  of the piston  420 , which places between the supporting portion  232  of the front frame  230  and the inner stator  320  of the reciprocating motor and performs a linear reciprocating motion by receiving the driving force form the reciprocating motor, is placed toward the supporting portion  232  of the front frame  230 , although the piston  420  is pushed by the gas pressure force, the piston  420  can move in a position-compensated state. 
   The piston  420  performs the linear reciprocating motion in the state pushed toward the reciprocating motor side by the pressure force, the flange portion  422  of the piston  420  in the eccentric state toward the front frame side is operated between the front frame  230  and the inner stator  320  of the reciprocating motor, and accordingly it is possible to prevent the flange portion  422  of the piston  420  from colliding against other construction parts. 
   In more detail, collision of the flange portion  422  against other parts is prevented, and a distance between the supporting portion  232  of the front frame  230  and the inner stator  320  of the reciprocating motor is minimized. 
   In addition, in the present invention, by making the distance (k) between the end surface (d) of the supporting portion  232  and the flange portion  422  smaller than the distance (m) between the end surface (c) of the cylinder  410  and the flange portion  422  of the piston  420 , when the flange portion  422  of the piston  420  excessively moves toward the front frame side in the unstable operation, the flange portion  422  does not collide against the cylinder  410  but collide against the supporting portion  232  of the front frame  230 , and accordingly impact of the collision can be minimized. 
   In addition, by making the distance (k) between the end surface (d) of the supporting portion  232  and the flange portion  422  of the piston  420  greater than a distance (r) between the discharge valve  620  and the end of the piston  420  (the suction valve  640  combined with the end of the piston  420 ), the piston  420  can move to the upper dead center without colliding the flange portion  422  against the supporting portion  232  of the front frame  230 . 
   In addition, by making the length (h) of the pole portion of the outer stator as the basis of the reciprocating motion distance of the mover  340  of the reciprocating motor smaller than an added distance ((k)+(m)) of the distance (k) between the end surface (d) of the supporting portion  232  and the flange portion  422  and the distance (m) between one side of the inner stator  320  of the reciprocating motor and the flange portion  422 , it is possible to prevent the flange portion  422  of the piston  420  performing the linear reciprocating motion with the mover  340  from colliding against the supporting portion  232  of the front frame  230  and the inner stator  320  of the reciprocating motor. 
   In addition, by making the distance (m) between the flange portion  422  of the piston  420  and the reciprocating motor facing the flange portion  422  smaller than a distance (p) between the end surface (n) of the mover  340  and the rear frame  210  facing the end surface (n), in the unstable operation of the mover  340  or the piston  420 , before the mover  340  collides against the rear frame  210 , the flange portion  422  of the piston  420  collides against a certain side of the inner stator  320  of the reciprocating motor, and accordingly it is possible to minimize damage of construction parts. 
   In addition, on the basis of the center of the open groove  311  at which the wound coil  330  is placed, the center of the permanent magnet  341  is placed toward the compression unit, when the piston  420  and the mover  340  are pushed by the pressure power in the operation, the mover  340  moves in the position-compensated state, and accordingly the permanent magnet  341  of the mover  340  does not escape from the end of the pole portion  312  of the outer stator  310  and move stably. 
   INDUSTRIAL APPLICABILITY 
   As described above, in the reciprocating compressor in accordance with the present invention, by preventing collision of parts moving with the mover of the reciprocating motor against other parts due to displacement occurred by the pressure power acting on the piston of the compression unit while pressing gas in the compression unit by receiving the linear reciprocating driving force of the reciprocating motor, damage of construction parts can be prevented, and accordingly it is possible to improve stability of the compressor. In addition, by constructing the parts compactly, it is possible to miniaturize the compressor.