Patent Publication Number: US-6659735-B2

Title: Scroll compressor

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a scroll compressor, and in particular to a scroll compressor which is capable of simplifying a structure of a valve, decreasing a size of a whole compressor and lowering a noise occurred in the valve by reducing the number of construction parts. 
     2. Description of the Prior Art 
     Generally, compressors can be divided into various kinds in accordance with compression methods, among them an air conditioning system required to be small-sized and lightweight mainly uses a scroll compressor. 
     FIG. 1 is a sectional view illustrating a scroll compressor in accordance with the prior art. 
     The scroll compressor in accordance with the prior art includes a casing  106  respectively connected to a suction pipe  102  at which a fluid is sucked, a discharge pipe  104  at which a compressed fluid is discharged and having a hermetically sealed certain space, a driving unit  108  placed at the lower portion of the casing  106  and generating a driving force, and a compressing unit  110  placed at the upper portion of the casing  106 , connected to the driving unit  108  by a rotational shaft  112 , compressing the fluid sucked through the suction pipe  102  and discharging it through the discharge pipe  104  by the rotation of the rotational shaft  112 . 
     A supporting frame  114  is installed inside the casing in order to support the rotational shaft  112  rotatively and support the compressing unit  110 , and a separation panel  120  is installed inside the casing  106  in order to divide the inner space of the casing  106  into a first chamber  116  putting a low pressure on a fluid and a second chamber  118  putting a high pressure on the fluid. 
     Because the driving unit  108  is constructed with a stator  122  fixed to the casing  106  and a rotor  124  installed to the inner circumference of the stator  122  and fixed to the rotational shaft  112 , when power is applied to the stator  122 , the rotor  124  is rotated by the mutual operation of the stator  122  and the rotor  124 , accordingly the rotational shaft  112  is rotated. 
     The compressing unit  110  includes a fixed scroll  128  formed with a fixed vane  126  having an involute shape and fixed to the separation panel  120 , and an orbiting scroll  132  formed as an orbiting vane  130  having an involute shape corresponding to vane  126  so as to have a certain compression space between the fixed vane  126  of the fixed scroll  128 , supported by the supporting panel  114  so as to perform an orbiting motion and orbiting in the rotation of the rotational shaft  112 . 
     A discharge passage  136  is formed at the center of the fixed scroll  128  in order to discharge the fluid compressed by the mutual operation of the fixed scroll  128  and the orbiting scroll  132  into the second chamber  118 , a check valve  138  is installed to the upper portion of the discharge passage  136  in order to prevent the fluid discharged into the second chamber  118  from flowing backward into the first chamber  116 , and a vacuum preventive valve  140  is installed to the side of the fixed scroll  128  in order to prevent the first chamber  116  from being in a vacuum state by flowing the fluid of the second chamber  118  to the first chamber  116  when the driving unit  108  is stopped or the suction pipe  102  is closed. 
     The check valve  138  is constructed with a valve body  142  combined to the central upper end portion of the fixed scroll  128  at which the discharge passage  136  is formed by a bolt and having a penetrated central portion so as to connect to the discharge passage  136 , and a piston type valve member  144  installed inside the valve body  142  so as to be movable up and down in order to close the discharge passage  136  by a self weight. 
     In the check valve  138 , when the fluid compressed by the mutual operation of the fixed scroll  128  and the orbiting scroll  132  is discharged into the discharge passage  136 , the valve member  144  is lifted by a pressure of the discharged fluid. Herein, the compressed fluid flows into the second chamber  118  while the discharge passage  136  is opened and is discharged outside through the discharge pipe  104 . 
     As depicted in FIG. 2, the vacuum preventive valve  140  includes a cylinder unit  150  formed at the side of the fixed scroll  128  so as to have a certain space, a valve spool  152  installed to the inner circumference of the cylinder unit  150  so as to be slidable, and an elastic member  158  engaged between the side surface of the valve spool  152  and the internal wall of the cylinder unit  150  and providing a certain elastic force to the valve spool  152 . 
     Herein, the side of the cylinder portion  150  is opened so as to connect with the first chamber  118 . And, the fluid compressed at the compression space between the fixed vane  126  and the orbiting vane  130  flows into the cylinder unit  150  through a first flow channel  154 , and because the cylinder unit  150  is connected to the second chamber  118  by a second flow channel  156 , the fluid inside the second chamber  118  flows into the cylinder unit  150 . 
     A spring constant of an elastic member  158  is smaller than a pressure of the fluid flowing into the first flow channel  154 . 
     In the vibration preventive valve  140 , when the fluid compressed in the compression space puts to the side of the cylinder unit  150  through the first flow channel  154  and operates on the valve spool  152 , the valve spool  152  is moved in the right direction in FIG. 2 by overcoming the elastic force of the elastic member  158 , accordingly the closed state of the second flow channel  156  can be maintained. 
     In the closed state, when the operation of the orbiting scroll  132  is stopped due to the stopping of the driving unit  108 , as depicted in FIG. 3, a hydraulic pressure acting on the valve spool  152  through the first flow channel  154  is removed, the valve spool  152  is moved in the left direction in FIG. 3 by the elastic force of the elastic member  158 . Herein, because the second flow channel  156  and the first chamber  116  are connected by the movement of the valve spring  152 , the high pressure fluid inside the second chamber  118  flows into the first chamber  116 , accordingly the first chamber  116  and the second chamber  118  can keep a balance pressure. 
     And, when the driving unit  108  is operated in the closed state of the suction pipe  102 , the hydraulic pressure acting on the valve spool  152  through the first flow channel  154  is removed, the valve spool  152  is moved in the left direction in FIG. 2, then, the second flow channel  156  and the second chamber  118  are connected each other, the fluid inside the second chamber  118  is supplied to the first chamber  116 , accordingly it is possible to prevent the first chamber from being in a vacuum state. 
     However, in the conventional scroll compressor, because a check valve preventing a backward flow of a fluid and a vacuum preventive valve preventing a first chamber from being in a vacuum state are respectively installed to a fixed scroll, the structure is complicate, and because the two valves are respectively installed to the fixed scroll, a space for housing the valves has to be increased, accordingly the size of a whole compressor is increased. 
     In addition, because the structure of the compressor is complicate due to the vibration preventive valve and the check valve, production processes are intricate, accordingly a production cost is increased. 
     In addition, because a valve member of the check valve is formed as a piston type, the valve member is moved up and down inside the valve body in accordance with a pressure of a fluid, when a discharge pressure is unstable, the valve member generates a noise by being collided with the internal wall of the valve body or the upper surface of the fixed scroll. 
     SUMMARY OF THE INVENTION 
     In order to solve the above-mentioned problems, it is an object of the present invention to provide a scroll compressor which is capable of simplifying a structure of a valve, decreasing a size of a whole compressor and reducing a production cost by having a function for preventing a fluid from flowing backward and a function for preventing a compressor from being a vacuum state simultaneously with one valve. 
     It is another object of the present invention to provide a scroll compressor which is capable of lowering a noise occurred in a valve due to an unstable state of a discharge pressure of a fluid in the operation of the compressor. 
     In order to achieve the above-mentioned objects, a scroll compressor in accordance with the present invention comprises a casing having a hermetically sealed certain space divided into a first chamber at which a fluid is sucked and a second chamber at which a compressed fluid is discharged, a driving unit housed inside the casing and generating a driving force, a compressing unit including a fixed scroll and an orbiting scroll connected to the driving unit by a rotational shaft in order to compress and discharge the fluid when the driving unit is operated, and a valve assembly rotatively installed to the upper surface of the fixed scroll, opening/closing a discharge hole at which the compressed fluid is discharged and opening/closing a passage connecting the first chamber and the second chamber each other. 
     An inner diameter of the passage is smaller than an inner diameter of the discharge hole. 
     The valve assembly is constructed with a rod part hinge-connected to the fixed scroll and curved at a certain angle in two directions centering around a hinge-connected point, a hinge part formed between the rod part and the upper surface of the fixed scroll and supporting the rod part rotatively, a first valve part formed at the end of the rod part and opening/closing the discharge hole and a second valve part formed at the other end of the rod part and opening/closing the passage. 
     The rod part is rotatively installed to the upper surface of the fixed scroll by the hinge part and has a plate shape curved at a certain angle in two directions centering around the hinge part. 
     The hinge part is constructed with a hinge bracket perpendicularly projected from the upper surface of the fixed scroll and having a hinge hole at which a hinge pin is inserted and a hinge protrusion upwardly projected from the curved portion of the rod part and having a hinge hole at which the hinge pin is inserted. 
     The first valve part is extended from one end of the rod part and is formed as a circular flat plate shape in order to open/close the discharge hole. 
     The first valve part is formed so as to have a diameter greater than an inner diameter of the discharge hole. 
     The second valve part is extended from the other end of the rod part and is formed as a circular flat plate shape in order to open/close the passage. 
     The second valve part is formed so as to have a diameter greater than an inner diameter of the passage. 
    
    
     BRIEF DESCRIPTION OF THE 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 is a sectional view illustrating a scroll compressor in accordance with the prior art; 
     FIG. 2 is an enlarged sectional view of an A portion of FIG. 1 illustrating a structure of a vacuum preventive valve of the scroll compressor in accordance with the prior art; 
     FIG. 3 is a state diagram illustrating an operation of a vacuum preventive valve of the scroll compressor in accordance with the prior art; 
     FIG. 4 is a sectional view illustrating a scroll compressor in accordance with the present invention; 
     FIG. 5 is a sectional view illustrating a structure of a compressing unit of the scroll compressor in accordance with the present invention; 
     FIG. 6 is a disassembled perspective view illustrating a valve assembly of the scroll compressor in accordance with the present invention; and 
     FIG. 7 is a state diagram illustrating an operation of the valve assembly of the scroll compressor in accordance with the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Hereinafter, the preferred embodiment of a scroll compressor in accordance with the present invention will be described with reference to accompanying drawings. 
     There can be a plurality of embodiments of a scroll compressor in accordance with the present invention, hereinafter the most preferred embodiment will be described. 
     FIG. 4 is a sectional view illustrating a scroll compressor in accordance with the present invention. 
     A scroll compressor in accordance with the present invention is constructed with a casing  2  having a hermetically sealed certain space, a driving unit  4  housed inside the casing  2  and generating a driving force, a compressing unit  6  connected with the driving unit  4  by a rotational shaft  8 , compressing a fluid and discharging the fluid when the driving unit  4  is operated, and a valve assembly, etc. installed to the side of the compressing unit  6 , preventing the fluid from flowing backward and preventing the internal space of the compressor from being in a vacuum state. 
     A suction pipe  10  at which a fluid is sucked and a discharge pipe  12  at which a compressed fluid is discharged are respectively connected to the side of the casing  2 . The casing  2  houses a supporting frame  14  rotatively supporting the rotational shaft  8  and supporting the compressing unit  6  and a separation panel  20  dividing the internal space of the casing  2  into a first chamber  16  connected to the suction pipe  10  and putting a low pressure on a fluid and a second chamber  18  putting a high pressure on the fluid. 
     The driving unit  4  is constructed with a stator  22  fixed to the inner circumference of the casing  2  and a rotor  24  placed at the inner circumference of the stator  22  and fixed to the rotational shaft  22 , when power is applied to the stator  22 , the rotor  24  is rotated by the mutual operation of the stator  22  and the rotor  24 , accordingly the rotational shaft  8  is rotated. 
     In the compressing unit  6 , a fixed vane  26  having an involute shape is formed, an orbiting vane  30  having an involute shape corresponded to the fixed vane  26  is formed so as to have a certain compression space, and an orbiting scroll  32  supported by the supporting panel  14  so as to perform an orbiting motion and orbiting in the rotation of the rotational shaft  8 . 
     A discharge hole  34  is formed at the central portion of the fixed scroll  28  in order to discharge the fluid compressed by the mutual operation of the fixed vain  26  and the orbiting vane  30  into the second chamber  18 , and a passage  36  connecting the first chamber  16  and the second chamber  18  is formed at the side of the fixed scroll  28  so as to have a certain distance from the discharge hole  34  in order to flow the fluid inside the second chamber  18  into the first chamber  16 . A valve assembly is installed to the upper surface of the fixed  28  in order to prevent the fluid from flowing backward by opening/closing the discharge hole  34  and flow a high pressure fluid inside the second chamber  18  into the first chamber  16  when the first chamber is in a vacuum state. 
     As depicted in FIGS. 5,  6  and  7 , the valve assembly includes a rod part  38  hinge-connected to the upper side surface of the fixed scroll  28  and curved at a certain angle in two directions from the hinge connection portion, a hinge part  40  formed between the rod part  38  and the upper surface of the fixed scroll  28  in order to support rotatively the rod part  38 , a first valve part  42  formed at the end of the rod part  38  and opening/closing the discharge hole  34 , and a second valve part  44  formed at the other end of the rod part  38  and opening/closing the passage  36 . 
     Herein, the rod part  38  is formed as a plate shape having a certain length and is curved at a certain angle in two directions centering around the hinge part  38 . 
     And, the hinge part  40  is constructed with a hinge bracket  48  projecting from the upper surface of the fixed scroll  28  and having a hinge hole  50  at which a hinge pin  46  is inserted into, and a hinge protrusion  56  upwardly projecting from the curved portion of the rod part  38  and having a hinge hole  58  at which the hinge pin  46  is inserted into. 
     In more detail, after arranging the hinge hole  50  of the hinge bracket  48  and the hinge hole  58  of the hinge protrusion  56  at the same linear line, the hinge pin  46  is inserted into them, accordingly the central portion of the rod part  38  is rotatively installed to the upper side surface of the fixed scroll  28 . 
     The first valve part  42  is extended from the end of the rod part  38 , is formed as a circular flat plate shape having a diameter greater than a diameter of the discharge hole  34 , is arranged so as to contact to the upper side surface of the discharge hole  34  and is rotated centering around the hinge part  40  in order to open/close the discharge hole  34 . 
     In more detail, the first valve part  42  opens the discharge hole  34  by the pressure of the fluid compressed by the mutual operation of the fixed scroll  28  and the orbiting scroll  32  and prevents the fluid from flowing backward by closing the discharge hole  34  by being closely adhered to the upper surface of the fixed scroll  28  by a self weight when the driving unit  4  is stopped. 
     The second valve part  44  is extended from the other end of the rod part  38 , is formed as a circular flat plate shape having a diameter greater than an inner diameter of the passage  36 , is arranged so as to contact to the upper surface of the fixed scroll  28  having the passage  36  and opens/closes the passage  36  while being rotated centering around the hinge part  40 . 
     In more detail, when the driving unit  4  is stopped, the second valve part  44  leaks the fluid inside the second chamber  18  to the first chamber  16  by opening the passage  36  in order to make the first chamber  16  and the second chamber  18  keep a balance pressure. In the closed state of the suction pipe  10 , when the driving unit  4  is operated, the passage  36  is opened, accordingly it is possible to prevent the second chamber  18  from being in the vacuum state. 
     Herein, the diameter of the first valve part  42  is greater than the diameter of the second valve part  44 , when the operation of the driving unit  4  is stopped and the hydraulic pressure acting on the first valve part  42  is removed, the first valve part  42  is operated in a direction closing the discharge hole  34  by the self weight, and the second valve part  44  is rotated together with the rotation of the first valve part  42  and is operated in a direction opening the passage  36 . 
     The operation of the valve assembly of the scroll compressor in accordance with the present invention will be described. 
     When power is applied to the driving unit  4 , the rotational shaft  8  is rotated by the mutual operation of the stator  22  and the rotor  24 , the orbiting scroll  32  performs the orbiting motion by the rotation of the rotational shaft  8 , accordingly the fluid sucking into the first chamber  16  through the suction pipe  10  is compressed. By the pressure of the fluid, the first valve part  42  is rotated centering around the hinge part  40 , the discharge hole  34  maintains the opened state, the compressed fluid flows into the second chamber  18  and is discharged outside through the discharge pipe  12 . 
     Herein, because the first valve part  42  is operated so as to open the discharge hole  34 , the second valve part  42  maintains the state closing the passage  36 . 
     In that state, when the driving unit  4  is stopped, the hydraulic pressure acting on the first valve part  42  is removed, the first valve part  42  is rotated centering around the hinge part  40  by the self weight, is closely adhered to the upper surface of the fixed scroll  28  and closes the discharge hole  34 , accordingly it is possible to prevent the fluid inside the second chamber  18  from flowing backward into the first chamber  16 . 
     And, according to the operation of the first valve part  42 , the second valve part  44  is operated in the direction opening the passage  36 , the fluid inside the second chamber  18  flows into the first chamber  16  through the passage  36 , accordingly the first chamber  16  and the second chamber  18  can keep a balance pressure. 
     And, in the closed state of the suction pipe  10 , when the driving unit  4  is operated, the first valve part  42  is closed, the second valve part  44  is opened, the fluid inside the second chamber  18  leaks to the first chamber  16 , the leaked fluid is pressurized in the compressing unit  6 , accordingly it is possible to prevent the first chamber  16  from being in a vacuum state. 
     The effect of the scroll compressor in accordance with the present invention will be described. 
     By forming a first valve part opening/closing a discharge hole and a second valve part opening/closing a passage as one body and hinge-connecting the body to the upper surface of a fixed scroll, a function for preventing a backward flow of a fluid and a function for preventing a vibration can be simultaneously performed, accordingly it is possible to simplify a structure, decrease a size of a compressor and reduce a production cost. 
     In addition, in a compression operation of a fluid by the operation of a driving unit, because a first valve part is formed as a flat plate shape, it does not collide with a discharge hole, accordingly it is possible to prevent a noise occurrence due to an unstable discharge pressure. 
     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.