Patent Publication Number: US-2004047751-A1

Title: Reciprocating compressor

Description:
RELATED APPLICATIONS  
       [0001] The present disclosure relates to subject matter contained in Korean Application No. 2002-0053586, filed on Sep. 5, 2002, which is herein expressly incorporated by reference in its entirety.  
       BACKGROUND OF THE INVENTION  
       [0002] 1. Field of the Invention  
       [0003] The present invention relates to a reciprocating compressor, and particularly, to a reciprocating compressor which increases a compression performance by improving the structures of a suction valve for controlling gas suction and a discharge valve for controlling gas discharge.  
       [0004] 2. Description of the Background Art  
       [0005] Generally, a compressor is an instrument for compressing a refrigerant gas under conditions of low temperature and pressure, which is introduced from an evaporator and discharging the gas by changing the conditions to high temperature and pressure.  
       [0006] Compressors can be classified as a rotary compressor, reciprocating compressor and a scroll compressor according to the method of compressing the fluid.  
       [0007] Particularly, the reciprocating compressor takes-in and compresses fluid while a piston moves linearly, and such reciprocating compressor is divided into a method (and device) which compresses fluid by converting the rotary movement of a driving motor into a reciprocating movement of the piston, and a method (and device) which takes-in and compresses fluid by having the piston perform a reciprocating movement as the driving motor performs a linear reciprocating movement.  
       [0008]FIG. 1 is a cross-sectional view showing a conventional reciprocating compressor, FIG. 2 is a partially cross-sectional view showing an operation state of a suction valve and a discharge valve in performing gas suction in FIG. 1, and FIG. 3 is a partially cross-sectional view showing an operation state of the suction valve and the discharge valve in performing gas discharge in FIG. 1.  
       [0009] As shown in the drawing, the conventional reciprocating compressor includes a case  10  having a gas suction pipe SP and gas discharge pipe DP, a frame unit  20  which is elastically installed inside the case  10 , a reciprocating motor  30  for generating a driving force while fixed to the frame unit  20 , a compression unit  40  for sucking, compressing and discharging gas by using a linear reciprocating force of the reciprocating motor  30 , and a resonance spring unit  50  for inducing resonating movement by elastically supporting the compression unit  40  in the movement direction.  
       [0010] The reciprocating motor  30  includes an outer stator  31  which is installed between the middle frame  22  and rear frame  23 , an inner stator  32  which is secured or coupled to the outer stator  31  at a predetermined spacing and is inserted and secured or coupled with the rear frame  23 , and a movable element  33  which is installed between the outer stator  31  and inner stator  32  for performing a linear reciprocating movement.  
       [0011] The compression unit  40  includes a cylinder  41  which is integrally formed in the front frame  21 , a piston  42  which is coupled with the movable element  33  of the reciprocating motor  30  for performing a reciprocating movement in a compression space P 1  of the cylinder  41 , a suction valve  43  which is mounted at the front end of the piston  42  for controlling suction of gas by opening and closing the suction path F of the piston  42 , and a discharging valve assembly  70  which is mounted at the discharging side of the cylinder  41  for controlling discharge of compression gas by opening and closing the compression space P 1 .  
       [0012] The discharging valve assembly  70  includes a discharging cover  71  for covering a side of the cylinder  41 , a discharging valve  72  which is inserted inside the discharging cover  71  for opening and closing the compression space P 1  of the cylinder  41 , and a valve spring  73  installed at the inner side of the discharging cover  71  for elastically supporting the discharging valve  72 .  
       [0013] An insertion groove  72   b  is formed at a pressure supporting surface  72   a , that is, a rear surface of the discharge valve  72 , and a head of a bolt B which fixed to the suction valve  43  protrudes therefrom. Accordingly, the head of the bolt is constructed to be inserted to the insertion groove  72   b  at the time of driving gas compression.  
       [0014] The operating process of the conventional reciprocating compressor with the above construction will be described as follows.  
       [0015] When a flux is generated between the outer stator  31  and inner stator  32  by applying a power source to the reciprocating motor  30 , the movable element  33  of the reciprocating motor  3  elastically performs a reciprocating movement against the resonance spring unit  50 .  
       [0016] At this time, as the piston  42  performs a reciprocating movement inside the cylinder  41 , the volume of the compression space P 1  is changed, and the gas is taken-in and compressed.  
       [0017] As the pressure of the gas is higher than a predetermined pressure, when it becomes higher than an elastic force of the valve spring  73 , the discharging valve  72  is moved. As the sequential process that the compression gas is discharged into the compression space P 2  is repeated, gas is discharged by opening and closing of the discharging valve  72  is discharged to the outside through a gas discharging pipe DP which is formed in the discharging cover  71 .  
       [0018] Hereinafter, referring to FIGS. 2 and 3, processes for taking-in, compressing, and discharging gas will be explained.  
       [0019] As shown in FIG. 2, when the piston  42  moves to a lower dead point (a), the discharge valve  72  of the discharging valve assembly  70  contacts an end portion of the cylinder  41  by a pressure difference, thereby closing the compression space P 1 .  
       [0020] At the same time, the suction valve  43  engaged to the piston  42  is bent and opens the suction path F, so that refrigerant gas is sucked in the compression space P 1  of the cylinder  41  through the suction path F of the piston  42 .  
       [0021] As shown in FIG. 3, the piston  42  moves to an upper dead point (b) after reaching to the lower dead point a, the suction valve  43  returns to an initial state and the suction path F is closed, thereby compressing the refrigerant gas sucked in the compression space P 1  of the cylinder  41 .  
       [0022] As the pressure of the gas is higher than a predetermined pressure, when it becomes higher than an elastic force of the valve spring  73 , the discharge valve  72  of the discharging valve assembly  70  is opened, thereby discharging the compressed refrigerant gas.  
       [0023] However, in the conventional compressor, the discharge valve  72  supported by the valve spring  73  does not move horizontally in the gas compression process, but moves in a slanted state.  
       [0024] That is because the valve spring  73  hardly has a horizontal disposition in a structure.  
       [0025] As aforementioned, when the discharge valve  72  moves in a slanted state not a horizontal state, the head (especially, an angular portion) of the bolt B is not inserted to the insertion groove  72   b  but contacts the adjacent portions or pressurized, thereby destroying the discharge valve and increasing the compression space. According to this, a dead volume is generated which serves to degrade a compression performance.  
       [0026] Also, in the conventional compressor, since the suction path is not formed at the center of the piston, gas is discharged without balance.  
       SUMMARY OF THE INVENTION  
       [0027] Therefore, an object of the present invention is to provide a reciprocating compressor which increases a compression performance by improving the structures of a suction valve for controlling gas suction and a discharge valve for controlling gas discharge.  
       [0028] To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, there is provided a reciprocating compressor comprising: a piston which reciprocates in a cylinder by receiving a driving force of a reciprocating motor and has a gas suction path therein; a suction valve mounted at an end surface of the piston to control flow of gas taken-in through the suction path; a valve assembly having a discharge cover engaged to one side of the cylinder, a discharge valve installed at an end portion of the cylinder to control gas discharge of a compression space formed by the cylinder and the piston, and a valve spring that elastically supports the discharge valve; and a suction valve fixing member engaged to a frontal surface of the piston that movably receives the suction valve back and forth.  
       [0029] The suction valve is provided with supporting surfaces at the outer circumference thereof, and suction surfaces that pass gas are formed between the supporting surfaces.  
       [0030] The suction valve fixing member is provided with a through hole connected to the suction path at a center of the frontal surface thereof.  
       [0031] A protrusion surface is formed at a center of the rear surface of the discharge valve to correspond to the through hole.  
       [0032] To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, there is also provided a reciprocating compressor comprising: a piston which reciprocates in a cylinder by receiving a driving force of a reciprocating motor and has a gas suction path therein; a suction valve mounted at an end surface of the piston to control flow of gas taken-in through the suction path; a valve assembly having a discharge cover engaged to one side of the cylinder, a discharge valve installed at an end portion of the cylinder to control gas discharge of a compression space formed by the cylinder and the piston, and a valve spring that elastically supports the discharge valve; a round head rivet that fixes the suction valve to the piston; and an insertion groove formed at the rear surface of the discharge valve to insert the round head rivet.  
       [0033] The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0034] 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.  
     [0035] In the drawings:  
     [0036]FIG. 1 is a sectional view of the conventional reciprocating compressor;  
     [0037]FIG. 2 is a partially cross-sectional view showing an operation state of the discharge valve assembly in operating suction of gas in the compressor of FIG. 1;  
     [0038]FIG. 3 is a partially cross-sectional view showing an operation state of the discharge valve assembly in operating discharge of gas in the compressor of FIG. 1;  
     [0039]FIG. 4 is a longitudinal sectional view showing a reciprocating compressor according to one preferred embodiment of the present invention;  
     [0040]FIG. 5 is a partially cross-sectional view showing an operation state of the discharge valve assembly in operating suction of gas in the compressor of FIG. 4;  
     [0041]FIG. 6 is a partially cross-sectional view showing an operation state of the discharge valve assembly in operating discharge of gas in the compressor of FIG. 4;  
     [0042]FIG. 7 is a disassembled perspective view showing an engagement mechanism of the suction valve and the piston;  
     [0043]FIG. 8 is a disassembled perspective view showing another engagement mechanism of the suction valve and the piston;  
     [0044]FIG. 9 is a frontal view showing a suction valve fixing member of the compressor of FIG. 4; and  
     [0045]FIGS. 10 and 11 show a part of the reciprocating compressor according to another preferred embodiment of the present invention, wherein FIG. 10 is a longitudinal sectional view showing an operation state of the discharge valve assembly in suctioning gas; and  
     [0046]FIG. 11 is a longitudinal sectional view showing an operation state of the discharge valve assembly in compressing gas. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
     [0047] Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings.  
     [0048] A reciprocating compressor according to the present invention will be explained with reference to the attached drawings.  
     [0049]FIG. 4 is a longitudinal sectional view showing a reciprocating compressor according to one preferred embodiment of the present invention, FIG. 5 is a partially cross-sectional view showing an operation state of the discharge valve assembly in operating suction of gas in the compressor FIG. 4, FIG. 6 is a partially cross-sectional view showing an operation state of the discharge valve assembly in operating discharge of gas in the compressor FIG. 4, FIG. 7 is a disassembled perspective view showing an engagement mechanism of the suction valve and the piston, FIG. 8 is a disassembled perspective view showing another engagement mechanism of the suction valve and the piston, and FIG. 9 is a frontal view showing a suction valve fixing member of the compressor FIG. 4.  
     [0050] As shown, a reciprocating compressor according to one preferred embodiment of the present invention comprises: a case  10  having a gas suction pipe SP and gas discharge pipe DP; a frame unit  20  installed in the case  10 ; a reciprocating motor  30  having a movable element which moves linearly; a piston  142  which reciprocates in the cylinder  141  by being connected to the movable element and has a gas suction path F therein; a suction valve  143  mounted at an end surface of the piston  142  for controlling a flow of gas sucked through the suction path F; a valve assembly  170  for controlling a discharge of compressed gas; and a suction valve fixing member  144  engaged to the frontal surface of the piston  142  for movably receiving the suction valve  143  as it moves back and forth.  
     [0051] The discharging valve assembly  170  includes a discharge cover  171  having a predetermined shape and formed to cover one side of the cylinder  141 , a discharge valve  172  inserted to the inner portion of the discharge cover  171  for opening and closing the compression space P 1  of the cylinder  141 ; and a valve spring  173  supported on the inner side of the discharge cover  171  and engaged to the discharge valve  172  for elastically supporting the discharge valve  172  while setting the position of the discharge valve  172 .  
     [0052] In said one preferred embodiment of the present invention, a suction valve fixing member  144  is engaged to a frontal surface of the piston  142  with a predetermined spacing in order to movably receive the suction valve  143  as it moves backward and forward, and a connection hole H connected to the suction path F is formed at a center of the frontal surface of the suction valve fixing member  144 . A dead volume preventing surface  172   a  protrudes from a center of the rear surface of the discharge valve  172  corresponding to the connection hole H.  
     [0053] In more detail, the suction valve fixing member  144  having a cylindrical shape includes a cylindrical body  144   b  engaged to the piston  142 , and a stopping portion  144   a  extending traversely from the end portion surface of the body  144   b  for restricting the movement of the suction valve  143 .  
     [0054] As shown in FIG. 7, when the suction valve fixing member  144  is engaged to the piston  142 , the suction valve fixing member  144  can be forcibly fit to a frontal side of the piston  142 .  
     [0055] Also, as shown in FIG. 8, the suction valve fixing member  144  can be engaged to the piston  142  by a male screw S 1  formed in front of the piston  142  and a female screw S 2  formed at the inner circumferential surface of the suction valve fixing member  144 .  
     [0056] The suction valve is formed as a thin plate and can include any components which are smoothly operated when gas is taken-in and compressed.  
     [0057] The suction valve  143  opens the suction path F at the time when gas is taken in, and closes the suction path F at the time when gas is compressed. The suction valve  143  includes a supporting surface  143   b  at an outer circumference and a suction surface  143   a  formed between the supporting surfaces  143   b  to pass gas.  
     [0058] That is, the supporting surface  143   b  is stopped by the stopping portion  144   a  of the suction valve fixing member  144 , and the suction surface  143   a  opens the suction path F of the piston  142  when operating to take-in gas and closes the connection hole H of the suction valve  143  when operating in compression of gas.  
     [0059] Operation of the reciprocating compressor according to one preferred embodiment of the present invention will be explained.  
     [0060] When the piston  142  moves to the lower dead point (a) by receiving a driving force of the reciprocating motor  30 , gas sucked to the suction path F pushes the suction valve  143  by a pressure difference.  
     [0061] At this time, the suction valve  143  installed at an inner surface of the suction valve fixing member  144  moves backward and thereby opens the suction path F. At the same time, gas which passed the suction path F passes the suction surface  143   a  of the suction valve  143  to pass the connection hole H, thereby being introduced to the compression space P 1 .  
     [0062] When the suction operation of gas is completed, the piston  142  goes forward, due to the action of the reciprocating motor  30 . At this time, the suction valve  143  goes back by the pressure difference and closes the suction path F of the piston  142 .  
     [0063] As the piston  142  reaches to the upper dead point (b) and the pressure of the gas is higher than a predetermined pressure, when it becomes higher than an elastic force of the valve spring  173 , the discharging valve  72  is moved and the gas is discharged.  
     [0064] Also, when the compressed gas of the compression space P 1  moves to the discharge space P 2  and thereby a pressure of the compression space P 1  becomes lower than a predetermined pressure, the discharge valve  172  returns to the initial state by the elastic force of the valve spring  173  and the sequential process of the gas being taken in and compressed is repeated.  
     [0065] In the first embodiment of the present invention, even if the discharge valve  172  moves in a slanted state, the dead volume preventing surface  172   a  of the discharge valve  172  is inserted to the connection hole H of the suction valve fixing member  144 , thereby preventing components from coming into contact and preventing a collision from occurring and minimizing the dead volume.  
     [0066] Also, since the suction path F is formed at the center of the piston  142 , gas is uniformly discharged, thereby not causing mass unbalance.  
     [0067]FIGS. 10 and 11 show a part of the reciprocating compressor according to another preferred embodiment of the present invention, wherein FIG. 10 is a longitudinal sectional view showing an operation state of the discharge valve assembly in performing gas suction and FIG. 11 is a longitudinal sectional view showing an operation state of the discharge valve assembly during gas compression.  
     [0068] As shown, in another embodiment of the present invention, there is still provided a reciprocating compressor comprising: a case  10  having a gas suction pipe SP and gas discharge pipe DP; a frame unit  20  installed in the case  10 ; a reciprocating motor  30  having a movable element which linearly moves; a piston  242  which reciprocates in the cylinder  241  by being connected to the movable element and has a gas suction path F therein; a suction valve  243  mounted at an end surface of the piston  242  for controlling a flow of sucked gas through the suction path F; a valve assembly  270  for controlling a discharge of compressed gas; a round head rivet R for fixing the suction valve  243  to the piston  242 ; and an insertion groove  272   b  formed at the rear surface of the discharge valve  272  for inserting the round head rivet R.  
     [0069] The discharging valve assembly  270  includes a discharge cover  271  having a predetermined shape and formed to cover one side of the cylinder  241 , a discharge valve  272  inserted to the inner portion of the discharge cover  271  for opening and closing the compression space P 1  of the cylinder  241 ; and a valve spring  273  supported on the inner side of the discharge cover  271  and engaged to the discharge valve  272  for elastically supporting the discharge valve  272  while setting or defining the position of the discharge valve  272 .  
     [0070] When the gas is compressed, an insertion groove  272   b  is formed at the rear surface of the discharge valve  272  in order to receive the round head rivet R.  
     [0071] In another embodiment of the present invention, when the piston  242  moves to the lower dead point (a) by receiving a driving force of the reciprocating motor  30 , gas sucked to the suction path F pushes the suction valve  243  due to a pressure difference.  
     [0072] At this time, the suction valve  243  goes backward and thereby opens the suction path F. At the same time, gas which passed the suction path F is introduced to the compression space P 1 .  
     [0073] When the suction operation of gas is completed, the piston  242  goes forward by receiving a driving force of the reciprocating motor  30 . At this time, the suction valve  243  goes back by the pressure difference and closes the suction path F of the piston  242 .  
     [0074] As the piston  242  reaches to the upper dead point (b) and the pressure of the gas is higher than a predetermined pressure, when it becomes higher than an elastic force of the valve spring  273 , the discharging valve  272  is moved and the gas is discharged.  
     [0075] Also, when the compressed gas of the compression space P 1  moves to the discharge space P 2  and thereby a pressure of the compression space P 1  becomes lower than a predetermined pressure, the discharge valve  272  returns to the initial state by the elastic force of the valve spring  273  and the sequential process by which gas is sucked and compressed is repeated.  
     [0076] In the another embodiment of the present invention, even if the discharge valve  272  moves in a slanted state at the time of gas compression, the round head rivet R is inserted to the insertion groove  272   b.    
     [0077] Accordingly, since the round rivet R does not contact or collide with the rear surface of the discharge valve  272 , the components are prevented from being damaged and the dead volume is minimized, thereby improving a compression performance.  
     [0078] As aforementioned, in the present invention, damage of the construction components by the collision with the discharge valve are prevented in operating compression of gas and the dead volume is minimized, thereby improving the compression performance of the compressor.  
     [0079] Also, since the suction path is formed at the center of the piston, gas is uniformly discharged, thereby not causing mass unbalance.  
     [0080] As the present invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be construed broadly within its spirit and scope as defined in the appended claims, and therefore all changes and modifications that fall within the metes and bounds of the claims, or equivalence of such metes and bounds are therefore intended to be embraced by the appended claims.