Abstract:
A compressor and device for reducing vibration therefor is provided herein. The compressor includes a compression device having a compression chamber, and configured to receive, compress, and output a refrigerant, a drive motor configured to rotate the compression device to compress a refrigerant within the compression chamber, and a torsional vibration absorbing device attached to the motor and configured to absorb torsional vibration.

Description:
[0001]    The application claims priority to Korean Application No. 10-2007-0027821 filed in Korea on May 21, 2007, which is herein incorporated by reference in its entirety. 
       BACKGROUND 
       [0002]    1. Field 
         [0003]    A compressor and a device for reducing vibration therefor are disclosed herein. 
         [0004]    2. Background 
         [0005]    Compressors are known. However, they suffer from various disadvantages. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]    Embodiments will be described in detail with reference to the following drawings in which like reference numerals refer to like elements, and wherein: 
           [0007]      FIG. 1  is a cross-sectional view of a scroll compressor having a device for reducing vibration according to an embodiment; 
           [0008]      FIGS. 2 and 3  are, respectively, a front view and an exploded perspective view showing the device for reducing vibration of  FIG. 1 ; 
           [0009]      FIG. 4  is an exploded perspective view of the device for reducing vibration of  FIG. 1 ; 
           [0010]      FIG. 5  is a graph showing a state of vibration generated in a related art scroll compressor without a device for reducing vibration according to an embodiment; 
           [0011]      FIG. 6  is a graph showing a state of vibration generated in a scroll compressor implementing a device for reducing vibration according to an embodiment; and 
           [0012]      FIGS. 7-9  are exemplary installations of a compressor having a device for reducing vibration according to embodiments. 
       
    
    
     DETAILED DESCRIPTION 
       [0013]    In general, a compressor is a device that converts mechanical or electrical energy into kinetic energy so as to compress a gas. A compressor may include a driving force generating device, which may include a driving motor to generate a driving force, and a compression device driven by the driving force generating device to compress a gas. Compressors may be categorized into various types, such as a rotary compressor, a scroll compressor, and a reciprocating compressor, according to the method of compression. 
         [0014]    In a scroll compressor, a rotation force generated by a driving motor may be transferred to an orbiting scroll through a rotational shaft. The orbiting scroll, which may be interlocked with a fixed scroll, performs an orbiting motion. A plurality of compression pockets or chambers may be formed by a fixed wrap of the fixed scroll and an orbiting wrap of the orbiting scroll. The compression chambers move toward a center of the scroll under the orbiting motion of the orbiting scroll, and the compression chambers change in volume as they move toward the center. Accordingly, a gas may be sucked, compressed, and discharged into a discharge space. 
         [0015]    In a scroll compressor, the rotational force generated by the driving motor may be transferred to the compression device via the rotational shaft, thereby generating an imbalance in the rotation during operation. In order to compensate for the imbalance in the rotation, one or more balance devices may be mounted on the rotational shaft or the driving motor. Such balance devices may include a main balance weight mounted on the rotation shaft to be disposed between the orbiting scroll and the driving motor, and a sub-balance weight mounted on a far end of the driving motor. 
         [0016]    Since the driving motor and the orbiting scroll are disposed with a certain gap therebetween, the balance devices may be suitable for balancing the force and moment to equilibrium. However, it is difficult to reduce the vibration occurring when an external force having a frequency N times the rotational speed of the rotational shaft is applied in a torsional direction. That is, when the driving motor is operated, a small torque ripple or torsional vibration may be generated by the driving motor. The vibration is generated in the rotor of the driving motor in a circumferential direction. The vibration may reduce the reliability of the compression device and its performance. 
         [0017]    Description will now be given in detail of a scroll compressor and a device for reducing vibration therefore according to an embodiment, examples of which are illustrated in the accompanying drawings. The present application shows an embodiment of a scroll compressor and device for reducing vibration therefore; however, the device for reducing vibration according to embodiments may be implemented in other types of compressors, for example, a rotary compressor. Further, the scroll compressor may be a low side scroll or reciprocal compressor or a high side scroll compressor. Further, although in the following description and accompanying drawings, for convenience of description, the compressor is shown and described in a vertical orientation, it will be readily understood by one skilled in the art that the compressor may be arranged in any orientation without difficulty. 
         [0018]      FIG. 1  is a cross-sectional view of a scroll compressor having a device for reducing vibration according to an embodiment.  FIGS. 2 and 3  are, respectively, a front view and an exploded perspective showing the device for reducing vibration of  FIG. 1 . 
         [0019]    As shown in  FIG. 1 , the scroll compressor  1  may include a casing  10 , a main frame  20  and a subframe  30  fixed, respectively, to inner upper and lower ends of the casing  10 , a driving motor  40  fixedly coupled to an inside of the casing  10  so as to be mounted between the main frame  20  and the subframe  30 , a fixed scroll  50  disposed from the main frame  20  with a certain gap therebetween and fixedly coupled to the inside of the casing  10 , an orbiting scroll  60  disposed between the fixed scroll  50  and the main frame  20  to perform an orbiting motion while being interlocked with the fixed scroll  50 , a rotational shaft  70  that transfers a driving force of the driving motor  40  to the orbiting scroll  60 , and an Oldham ring  80  inserted between the orbiting scroll  60  and the main frame  20  that prevents the orbiting scroll  60  from rotating on its axis. The driving motor  40  may include a stator  42  fixed inside of the casing  10 , and a rotor  44  rotatable inside of the stator  42 . 
         [0020]    The rotational shaft  70  may include a shaft portion  72  having a certain length, and an eccentric portion  71  formed at one end of the shaft portion  72  so as to be eccentric with respect to a center of a shaft portion  72 . A middle portion of the shaft portion  72  of the rotational shaft  70  may be fixed within the rotor  44  of the driving motor  40 . The eccentric portion  71  of the rotational shaft  70  may be engaged in a boss  63  formed at a rear or lower surface of the orbiting scroll  60 . A main balance weight  110  may be mounted on the shaft portion  72  of the rotational shaft  70  which is disposed between the orbiting scroll  60  and the rotor  44 . A sub-balance weight  120  may be fixed to a lower end of the rotor  44 . End-rings  45   a  and  45   b  may be mounted on the upper and lower ends of the rotor  44 , respectively. The sub-balance weight  120  may be fixed to the end-ring  45   b  disposed at the lower end of the rotor  44 . 
         [0021]    Further, a vibration absorbing device or unit may be mounted on the rotational shaft  70 , the rotor  44 , or the sub-balance weight  120 . The vibration absorbing device absorbs vibration generated in a rotational direction. 
         [0022]    The sub-balance weight  120  may be mounted on the lower end-ring  45  of the rotor  44 , and the vibration absorbing device may be mounted at an assembly including the lower end-ring  45   b  and the sub-balance weight  120  integrally assembled. Further, the main balance weight  110  may be formed in a ring shape and may include a ring-shaped fixing portion  111  fixedly inserted into the shaft portion  72  of the rotational shaft  70 , and a mass portion  112  extending at one side of the ring-shaped fixing portion  111  in a certain shape to have a volume. When the main balance weight  110  is coupled to the shaft portion  72  of the rotational shaft  70 , the mass portion  112  of the main balance weight  110  may be positioned at an opposite side to the eccentric portion  71 . 
         [0023]    Alternatively, the configurations of the main balance weight  110  and the sub-balance weight  120  may be reversed. In such a case, the vibration absorbing device may be incorporated into the assembly including the sub-balance weight  120 . 
         [0024]    As shown in  FIG. 4 , the assembly integrally formed of the lower end-ring  45   b  and the sub-balance weight  120  may include the lower end-ring  45   b  in the form of a disk  45   c  having a certain thickness and area and provided with a through hole  45   d  so as to pass the rotational shaft  70  through a center thereof, and the sub-balance weight  120  comprising a pair of masses  121 ,  122  coupled to one side of the disk  45   c  with a gap therebetween. The masses  121 ,  122  may be formed in a circular arc shape having a certain width and thickness. The masses  121 ,  122  may be disposed at one side of the disk  45   c,  for example, in an area corresponding to one half of the disk  45   c.  One end surface of each of the masses  121 ,  122  may face the other. The masses  121 ,  122  may be fixedly coupled to the disk  45   c  by means of, for example, screws. Meanwhile, the pair of masses  121 ,  122  may be integrally formed with the disk  45   c,  or may be formed in various other shapes. 
         [0025]    The vibration absorbing device may include a pivot shaft  130  disposed between the two masses  121 ,  122 , and an absorber  140  inserted onto the pivot shaft  130  and movable in a circumferential direction of the rotational shaft  70 . The pivot shaft  130  may include a fixing pin  131  and a fixing bolt  132 . The fixing pin  131  may have a certain external diameter and length, may be fixed to the disk  45   c,  and may have a threaded hole at a center thereof Further, the fixing bolt  132  may be threaded into the threaded hole of the fixing pin  131  to prevent the separation of the absorber  140  therefrom. The fixing pin  131  may be integrally formed with the disk  45   c.  The pivot shaft  130  may be disposed between the two masses  121 ,  122 . 
         [0026]    The absorber  140  may include a long shaft portion  141  having a certain width and length, a pin hole  142  formed at an outer end of the long shaft portion  141 , and lateral protrusion portions  143  each extending to the sides of the other end of the long shaft portion  141  a certain length. The lateral protrusion portions  143  may be positioned at an opposite end to the pin hole  142 , and may be formed to have the same height as the long shaft portion  141  with a certain length. The height of the absorber  140  may be fixed and may correspond to the heights (thicknesses) of the two masses  121 ,  122 . The outer ends of both the lateral protrusion portions  143  may be formed in a curved shape. Also, the outer end of the long shaft portion  141  and the outer surface of each of the two lateral protrusion portions  143  may be formed to have a curved shape. Additionally, the lateral protrusion portions  143  of the absorber  140  may include a collision absorbing layer. 
         [0027]    After the pin hole  142  of the absorber  140  is inserted onto the fixing pin  131  coupled to the disk  45   c,  the fixing bolt  132  may be coupled into the threaded hole in the fixing pin  131 . The head of the fixing bolt  132  may prevent the separation of the absorber  140  therefrom. 
         [0028]    Further, a center of gravity of the absorber  140  may be positioned at the long shaft portion  141 . The center of gravity of the absorber  140  may be spaced from the pin hole  142  by a certain distance. The pin hole  142  may be disposed from the center of the disk  45   c  by a certain distance therebetween. Accordingly, a distance between the center of gravity of the absorber  140  and the center of the disk  45   b  may be greater than a distance between the center of the pin hole  142  and the center of the disk  45   b.  However, the distance between the center of gravity of the absorber  140  and the center of the disk  45   b  may be shorter than the distance between the center of the pin hole  142  and the center of the disk  45   c.  That is, the center of gravity of the absorber  140  may be disposed between the center of the disk  45   b  and the pin hole  142 . 
         [0029]    When the absorber  140  is coupled onto the pivot shaft  130 , the disk  45   c  may be fixedly coupled to the lower end surface of the rotor  44  of the driving motor. Thus, the disk  45   c  forms the end-ring  45   b  at the lower end of the rotor  44 . 
         [0030]    Further, an assembly is formed of the disk  45   c,  the two masses  121 ,  122 , the fixing pin  131 , and the absorber  140 . The assembly may be formed as a separate assembly and fixed at a certain location of the rotational shaft  70 . That is, although the disk  45   c  forms the end-ring  45   b  at the lower end of the rotor  44 , the end-ring of the rotor  44  may be separately formed. An assembly having the disk  45   c  may be separately formed, thus, to fix the assembly to a certain location of the rotational shaft  70 . 
         [0031]    A suction pipe  11  and a discharge pipe  12  may be coupled to the casing  10 , respectively, and a lower portion of the casing  10  filled with oil. The scroll compressor may be a high pressure scroll compressor which operates at a high pressure inside the casing, or a low pressure scroll compressor which operates at a low pressure inside the casing. Moreover, in the drawings, reference numeral  42  denotes a stator,  90  denotes a high/low pressure separator,  100  denotes a check valve, H denotes a high pressure space, and L denotes a low pressure space. 
         [0032]    Hereinafter, an operation of the vibration absorbing device in a scroll compressor according an embodiment will be described in detail. 
         [0033]    In the scroll compressor, when power is applied to the driving motor  40 , the driving motor  40  is operated. The rotational force of the driving motor  40  is transferred to the orbiting scroll  60  through the eccentric portion  71  of the rotational shaft  70 . Then, the orbiting scroll  60  performs an orbiting motion while interlocked with the fixed scroll  50  due to the rotational force while constrained by the Oldham ring  80  so as not to rotate on its axis. 
         [0034]    As the orbiting scroll  60  performs the orbiting motion, a wrap  62  of the orbiting scroll  60  performs an orbiting motion while being interlocked with a wrap  52  of the fixed scroll  50 . A plurality of compression pockets P are formed between the wrap  62  of the orbiting scroll  60  and the wrap  52  of the fixed scroll  50 . As the compression pockets P move toward the centers of the fixed and orbiting scrolls  50  and  60 , the compression pockets P change (for example, decrease) in volume. Accordingly, a gas is sucked, compressed, and discharged through a discharge hole  53  in the fixed scroll  50 . 
         [0035]    The rotational force from the driving motor  40  is transferred to the orbiting scroll  60  by the rotational shaft  70 , and thus the orbiting scroll  60  performs an orbiting motion while being eccentrically coupled to the fixed scroll  50  to compress a gas. During the compression of the gas, the distance difference between the driving motor  40  and the orbiting scroll  60  generates force and moment disequilibrium. 
         [0036]    The force and moment disequilibrium is compensated by the main balance weight  110  and the sub-balance weight  120 . The rotation mass comprised of the rotational shaft  70 , the rotor  44 , and the orbiting scroll  60  may have a counteracting force and moment equilibrium, thereby maintaining a dynamically stable state. 
         [0037]    Further, when vibration occurs in the rotational direction due to a torque ripple generated by the driving motor  40  generating the rotational force or due to an external force, the absorber  140  of the vibration absorbing device is displaced in the rotational direction of the rotation mass, that is, in a circumferential direction, centering around the pivot shaft  130  and thereby absorbs, or damps the angular vibration generated in the rotational direction. 
         [0038]    More specifically, when a torque ripple is generated by the driving motor  40 , a small angular vibration is generated by the rotor  44  of the driving motor in the rotational direction. The vibration is transferred to the rotation mass having the rotor  44 , and the rotation mass then vibrates in the rotational direction. In this case, as the absorber  140  is displaced in the rotational direction centering around the pivot shaft  130 , the vibration of the rotation mass in the rotational direction is canceled and dampened. 
         [0039]      FIG. 5  is a graph showing a vibration state occurring in a scroll compressor without a vibration absorbing device.  FIG. 6  is a graph showing a vibration state occurring in a scroll compressor with a vibration absorbing device according to embodiments. As shown, the vibration absorbing device according to embodiments may significantly reduce the vibration in the scroll compressor. The vibration absorbing device according to embodiments may also be applied to, for example, a reciprocal compressor or a rotary compressor that compresses a gas by receiving a rotational force of the motor, in addition to a scroll compressor. 
         [0040]    As described above, when vibration is generated in a rotational direction by the driving motor generating the rotational force or due to an external force, the device for reducing vibration in a compressor according to embodiments may absorb the vibration in the rotational direction, thereby minimizing the occurrence of the vibration in the compressor. Accordingly, the reliability of the compressor may be enhanced. Further, when a refrigerating cycle device employing the compressor is mounted in an air conditioner, the vibration propagated by a pipeline connecting components of the air conditioner to each other may be minimized, thus, enhancing the reliability of the product. 
         [0041]    A device for reducing vibration in a compressor according to embodiments disclosed herein may minimize a vibration occurring when a gas is compressed by receiving a rotation force from a driving motor. In accordance with one embodiment, as embodied and broadly described herein, there is provided a device for reducing vibration in a compressor that includes a rotation shaft for transferring a rotation force of a motor to a compression part, and a vibration absorbing unit for absorbing a vibration occurring in a rotation mass comprised of the rotation shaft and a rotor of the motor. 
         [0042]    Although a scroll compressor is presented herein, for ease of discussion, it is well understood that the device for reducing vibration according to embodiments disclosed herein may be equally applied to other types of compressors, or another application in which this type of vibration reducing is required and/or advantageous. 
         [0043]    More specifically, the compressor and device for reducing vibration according to embodiments disclosed herein may have numerous applications in which compression of fluid is required. Such applications may include, for example, air conditioning and refrigeration applications. One such exemplary application is shown in  FIG. 7 , in which a compressor  710  having a device for reducing vibration according to embodiments disclosed herein is installed in a refrigerator/freezer  700 . Installation and functionality of a compressor in a refrigerator is discussed in detail in U.S. Pat. Nos. 7,082,776, 6,955,064, 7,114,345, 7,055,338, and 6,772,601, the entirety of which are incorporated herein by reference. 
         [0044]    Another such exemplary application is shown in  FIG. 8 , in which a compressor  810  having a device for reducing vibration according to embodiments disclosed herein is installed in an outdoor unit air conditioner  800 . Installation and functionality of a compressor in a refrigerator is discussed in detail in U.S. Pat. Nos. 7,121,106, 6,868,681, 5,775,120, 6,374,492, 6,962,058, 6,951,628, and 5,947,373, the entirety of which are incorporated herein by reference. 
         [0045]    Another such exemplary application is shown in  FIG. 9 , in which a compressor  910  having a device for reducing vibration according to embodiments disclosed herein is installed in a single, integrated air conditioning unit  900 . Installation and functionality of a compressor in a refrigerator is discussed in detail in U.S. Pat. Nos. 7,032,404, 6,412,298, 7,036,331, 6,588,228, 6,182,460, and 5,775,123, the entirety of which are incorporated herein by reference 
         [0046]    A device for reducing vibration in a compressor according to embodiments disclosed herein may minimize a vibration occurring when a gas is compressed by receiving a rotation force from a driving motor. 
         [0047]    In accordance with one embodiment, as embodied and broadly described herein, there is provided a device for reducing vibration in a compressor that includes a rotation shaft for transferring a rotation force of a motor to a compression part, and a vibration absorbing unit for absorbing a vibration occurring in a rotation mass comprised of the rotation shaft and a rotor of the motor. 
         [0048]    The above references ate incorporated by reference herein where appropriate for appropriate teachings of additional or alternative details, features and/or technical background. 
         [0049]    Any reference in this specification to “one embodiment,” “an embodiment,” “example embodiment,” etc., means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with any embodiment, it is submitted that it is within the purview of one skilled in the art to effect such feature, structure, or characteristic in connection with other ones of the embodiments. 
         [0050]    Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art.