Abstract:
A suction unit includes a suction motor for generating air flow; a noise reduction unit which surrounds the suction motor and acts as a resonator in order to reduce noise generated during the operation of the suction motor; and a motor chamber which surrounds the noise reduction unit. The noise reduction unit includes an air flow path which provide a path of air flowing by the suction motor, a noise reduction chamber for eliminating the noise of at least one frequency band, and at least one communicating hole which causes sound wave of the noise to enter the noise reduction chamber. The air flow path is divided from the noise reduction chamber and thus the sound wave of the noise enters the noise reduction chamber through the communicating hole during a process in which air passes through the air flow path.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority under 35 U.S.C. §119 and 35 U.S.C. §365 to Korean Application No. 10-2015-0115957 (filed on Aug. 18, 2015), which is hereby incorporated by reference in its entirety. 
       BACKGROUND 
       [0002]    1. Field 
         [0003]    The present disclosure relates to a suction unit. 
         [0004]    2. Background 
         [0005]    Generally, the suction unit may be provided in a cleaner and be used to suck the air including the dust. 
         [0006]    The suction unit may include a suction motor and a motor chamber housing the suction motor. Noise is generated in a process of operating the suction motor. Accordingly, a resonator may be used in order to reduce the noise. 
         [0007]    A noise reduction device of a vacuum cleaner is disclosed in Korea Patent Publication No. 10-0710232 (registration date 04.16.2007) which is a related art of the present disclosure. 
         [0008]    The noise reduction device of related art includes a resonator provided in the outside of the motor chamber. The resonator is provided in the outside of the outer peripheral surface of the motor chamber. 
         [0009]    However, according to the related art, the resonator is capable of reducing the noise with a specific frequency, however there is a problem that since the resonator is provided in the outside of the motor chamber, a portion of the air flowing by the suction motor may flow the resonator and then vortex is generated in the inlet side of the resonator and thus the flow noise due to the vortex is increased. 
       SUMMARY 
       [0010]    The present disclosure is directed to a suction unit which is capable of minimizing noise generated when a suction motor is operated. 
         [0011]    The present disclosure is directed to a suction unit which is capable of reducing discharge noise without increasing or changing the size thereof, by a reduction unit being mounted on the upstream portion and the downstream portion of the suction motor. 
         [0012]    A suction unit includes a suction motor for generating air flow; a noise reduction unit which surrounds the suction motor and acts as a resonator in order to reduce noise generated during the operation of the suction motor; and a motor chamber which surrounds the noise reduction unit. The noise reduction unit includes an air flow path which provide a path of air flowing by the suction motor, a noise reduction chamber for eliminating the noise of at least one frequency band, and at least one communicating hole which causes sound wave of the noise to enter the noise reduction chamber. The air flow path is divided from the noise reduction chamber and thus the sound wave of the noise enters the noise reduction chamber through the communicating hole during a process in which air passes through the air flow path. 
         [0013]    According to the present invention, since the noise reduction unit provided within the motor chamber houses the suction motor, the noise reduction unit is primarily capable of reducing the noise and the motor chamber is secondarily capable of reducing the noise. Accordingly, three is an advantage that the noise generated during the operation of the suction motor is further capable of being reduced. 
         [0014]    In addition, since a plurality of communicating holes are formed in the circumferential direction of the guide body in the process of air flowing the guide body, a generation of the flowing noise of air due to swirl in the perimeter of the communicating hole may be prevented. 
         [0015]    Further, since the noise reduction unit directly surrounds the suction motor, distance in which the sound wave of the noise of the specific frequency band moves to the noise reduction unit is reduced. According to this, there is an advantage that the change of the frequency of the sound wave is minimized in the process of the sound wave of the noise being moved and thus the reduction of capability of the sound reduction unit is prevented. 
         [0016]    In addition, in a case of the present invention, there is an advantage that the noise reduction unit is disposed in the upstream or the downstream of the suction motor in the motor chamber, and thus the discharging noise may be reduced without increasing or changing the size of the noise reduction unit. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]      FIG. 1  is an exploded perspective view illustrating a suction unit according to an embodiment of the present invention. 
           [0018]      FIG. 2  is a cross-sectional view illustrating a suction unit according to an embodiment of the present invention. 
           [0019]      FIG. 3  is an exploded perspective view illustrating a noise reduction unit according to an embodiment of the present invention. 
           [0020]      FIG. 4  is a cross-sectional view illustrating a noise reduction unit according to an embodiment of the present invention. 
           [0021]      FIG. 5  is a graph illustrating frequency-dependent noise according to the presence or absence of the noise reduction unit. 
           [0022]      FIG. 6  is a cross-sectional view illustrating a noise reduction unit according to the other embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0023]      FIG. 1  is an exploded perspective view illustrating a suction unit according to an embodiment of the present invention, and  FIG. 2  is a cross-sectional view illustrating a suction unit according to an embodiment of the present invention. 
         [0024]      FIG. 3  is an exploded perspective view illustrating a noise reduction unit according to an embodiment of the present invention. 
         [0000]      FIG. 4  is a cross-sectional view illustrating a noise reduction unit according to an embodiment of the present invention. 
         [0025]    With reference to  FIG. 1  to  FIG. 4 , the suction unit  1  according to the an embodiment of the present invention may be mounted on the inside of the vacuum cleaner and then may be used, as an example. 
         [0026]    The suction unit  1  may include a suction motor  10  for generating the suction force, a noise reduction unit  20  for housing the suction motor  10  and reducing the noise generated during the operation of the suction motor  10 , and a motor chamber  30  housing the noise reduction unit  20 . 
         [0027]    The suction motor  10  may include an impeller (not illustrated) and a drive portion for rotating the impeller and since the suction motor  10  due to known structures may be implemented in the present example, a detailed description regarding those is omitted. 
         [0028]    The motor chamber  30  may include a first motor chamber  31  and a second motor chamber  32  which is coupled with the first motor chamber  31 . 
         [0029]    An inlet  320  through which air is passed is provided in the second motor chamber  32  and an outlet  312  from which the air is passed by the suction motor  10  is discharged is provided in the first motor chamber  31 . 
         [0030]    The noise reduction unit  20  may include a first reduction unit  21  and a second reduction unit  25  coupled with the first reduction unit  21 . 
         [0031]    The first reduction unit  21  is positioned on the upstream of the suction motor  10  and the second reduction unit  25  may be positioned on the downstream of the suction motor  10 . 
         [0032]    The noise reduction unit  20  may surround the suction motor  10 . In other words, the noise reduction unit  20  is disposed in the inside of the motor chamber  30  and the suction motor  10  is positioned in the inside of the noise reduction unit  20 , in the present embodiment. 
         [0033]    According to the present invention, since the noise reduction unit  20  is primarily capable of reducing the noise and the motor chamber  30  is secondarily capable of reducing the noise. Accordingly, there is an advantage that the noise generated during the operation of the suction motor  10  may be further reduced. 
         [0034]    The noise reduction unit  20  reduces the noise according to elimination of the noise of the specific frequency band and the suction motor  10  is shielded. Accordingly, the noise reduction unit  20  serves to prevent noise from propagating to the outside. 
         [0035]    The first reduction unit  21  may be coupled to the upper side of the second reduction unit  25 , as an example. 
         [0036]    At this time, in a case where the second reduction unit  25  is omitted, the first reduction unit  21  may be coupled to the motor chamber  30 . Alternatively, in a case where the first reduction unit  21  is omitted, the second reduction unit  25  may be coupled to the motor chamber  30 . 
         [0037]    The first reduction unit  21  may include a frame which surrounds a portion of the suction motor  10 . The frame may include a first frame  210  and a second frame  230  which is coupled to the upper side of the first frame  210 , but it is not limited to this. 
         [0038]    An air flowing portion  232  for causing air to flow to the suction motor  10  may be provided in the second frame  230 . The air flowing portion  232  may be inserted into the inlet  320  of the first motor chamber  32 . 
         [0039]    An air guide portion  220  in which air passed by the air flowing portion  232  is guided in the suction motor  10  may be provided in the first frame  210 . 
         [0040]    The air guide portion  220  may include a guide body  221  which has a smaller diameter than the diameter of the inner peripheral surface of the first frame  210  and an extending portion  228  which is extended from the guide body  221  in the radial direction. 
         [0041]    The guide body  221  may be formed in a cylindrical shape and has an air flow path  222  for flowing of air, as an example. At this time, air flows the air flow path  222  in the axial direction of the guide body  221 . 
         [0042]    The extending portion  228  is extended in the radial direction in the guide body  221  and then may be in contact with the inner peripheral surface of the first frame  210 . 
         [0043]    At least one first communicating hole  224  may be formed in the guide body  221 .  FIG. 4  is a view illustrating that a plurality of first communicating holes  224  are formed in the guide body  221 . 
         [0044]    The outer peripheral surface of the guide body  221  and the inner peripheral surface of the first frame  210  define the first noise reduction chamber  212 . 
         [0045]    In the present embodiment, the plurality of first communicating holes  224  formed in the guide body  221  and the first noise reduction chamber  212  serve as a first resonator. At this time, a first noise reduction chamber  212  may be communicate with the plurality of the first communicating holes  224 . The first noise reduction chamber  212  is disposed to surround the guide body  221 . 
         [0046]    The plurality of first communicating holes  224  serve as an inlet which allows the sound wave of the noise to enter the first noise reduction chamber  212 . 
         [0047]    Specifically, a specific standing wave of the noise which is generated during operation of the suction motor  10  as a noise which is generated while air flows the suction motor  10  is moved to the first noise reduction chamber  212  passing by the plurality of first communicating holes  224 . The specific standing wave moved to the first noise reduction chamber  212  is changed to the vibration in an out of phase form and then passes through the first communicating hole  224 . Accordingly, a phase shifting with respect to the specific standing wave generates and then the specific standing wave generated at the suction unit  1  is eliminated. According to this, the noise may be reduced. 
         [0048]    At this time, since air flows an inner space of the guide body  221 , so that the flow noise due to the first communicating hole  224  is not generated, the plurality of first communicating holes  224  may be disposed to be spaces apart in the circumferential direction of the guide body  221 . 
         [0049]    If a first communicating hole is formed on the guide body  221 , swirl is generated in the perimeter of the first communicating hole by the first communicating hole in a process during which air passes through the guide body  221 . According to this, there may be a problem that the flow noise of air is generated. 
         [0050]    In a case where a plurality of first communicating holes  224  are formed in the circumferential direction of the guide body  221  as the present embodiment, and air flows in the axial direction of the guide body  221 , air is prevented from being concentrated on only a portion of the plurality of first communication holes  224 . Accordingly, swirl is prevented from being generated in the first communicating hole. Accordingly, the flow noise of air may be prevented from being generated by the swirl. 
         [0051]    Naturally, a portion of the plurality of the first communicating holes  224  may be disposed to be space apart in the axial direction of the guide body  221 . 
         [0052]    The noise with specific frequency bands which is generated in the suction unit  1  may be reduced by adjusting the number of the plurality of first communicating holes  224 , the diameter and the length of the plurality of first communicating holes  224 , and the volume of the first noise reduction chamber  212 . 
         [0053]    The frame cover  240  may be provided in the outside of the first frame  210 . The frame cover  240  may be fastened to the motor chamber  30 . 
         [0054]    Meanwhile, the second reduction unit  25  may further include a motor cover  250  which covers the suction motor  10  and a chamber forming portion  260  which is coupled to the outside of the motor cover  250 . 
         [0055]    The motor cover  250  may form in a cylindrical shape with upper side being opened, as an example, and may have a plurality of air holes  252  in the circumferential direction. 
         [0056]    The motor cover  250  may be coupled with the first frame  210  but it is not limiting to this. As an example, a portion of the upper side of the motor cover  250  may be fastened to the motor cover  250  and the first frame  210  by a screw in a state where the a portion of the upper side of the motor cover  250  is inserted into the first frame  210 . In the present invention, there is no restriction in the fastening method of the motor cover  250  and the first frame  210 . 
         [0057]    At least one second communicating hole may be formed in the bottom wall  251  of the motor cover  250 .  FIG. 4  is a view illustrating that a plurality of first communicating holes  254  are formed in the bottom wall  251 , as an example. 
         [0058]    The chamber forming portion  260  is coupled to the bottom wall  251  in the outside of the motor cover  250  and thus may form the first noise reduction chamber  262  with the bottom wall  251 . 
         [0059]    In other words, in the present embodiment, the plurality of second communicating holes  254  and the second noise reduction chamber  262  serve as a second resonator. At this time, a second noise reduction chamber  260  may be communicate with the plurality of the second communicating holes  254 . The internal space of the motor cover  250  provides an air flow path in which air discharged from the suction motor  20  flows. 
         [0060]    The noise with specific frequency bands which is generated in the suction unit  1  may be reduced by adjusting the number of the plurality of second communicating holes  254 , the diameter and the length of the plurality of second communicating holes  254 , and the volume of the second noise reduction chamber  262 . 
         [0061]    At this time, the first resonator and the second resonator may be designed to have natural frequencies which are different from each other. 
         [0062]    For example, the number, the diameter, or the length of the inlet hole of the first resonator may be designed to be different from the number, the diameter, or the length of the inlet hole of the second resonator. 
         [0063]    Alternatively, the volume of the noise reduction chamber of the first resonator may be designed to be different from the volume of the noise reduction chamber of the second resonator. 
         [0064]      FIG. 5  is a graph illustrating frequency-dependent noise according to the presence or absence of the noise reduction unit. 
         [0065]    With reference to  FIG. 5 , it can be found that about 1900 hz of frequency noise may remarkably reduced by the first reduction unit  21  by the natural frequencies of the first reduction unit  21  and the second reduction unit  25  being designed to be different from each other and about 2300 hz of frequency noise is remarkably reduced by the second reduction unit  25 . 
         [0066]    The graph in  FIG. 5  is an example and the frequency band of the noise may be differentiated according to specification, structure or the type of the suction motor  10  and according to this, the natural frequency of the noise reduction unit may be also differentiated. 
         [0067]      FIG. 6  is a cross-sectional view illustrating a noise reduction unit according to the other embodiment of the present invention. 
         [0068]    The present embodiment is the same as the previous embodiments in the other part except for the structure of the second resonator in the noise reduction unit. Accordingly, hereinafter, only the characteristic parts of the present embodiment will be described. 
         [0069]    With reference to  FIG. 6 , the second noise reduction unit  25  of the present embodiment may include the motor cover  250 . 
         [0070]    The motor cover  250  may include a chamber forming portion  256  for forming the second noise reduction chamber  264 . The chamber forming portion  256  may be a portion in which the diameter of the motor cover  250  is reduced compared to the other portion. However, it is not limited to this. 
         [0071]    Accordingly, the motor cover  250  may include a step portion  258  and chamber forming wall  270  for forming the second noise reduction chamber  64  may be seated in the step portion  258 . The plurality of second communicating holes  272  may be formed in the chamber forming wall  270 . 
         [0072]    According to the present embodiment, the plurality of second communicating holes  272  of the chamber forming wall  270  and the second noise reduction chamber  264  serve as a second resonator.