Patent Publication Number: US-2019167026-A1

Title: Juicer that is easy to manufacture and improves performance

Description:
CROSS REFERENCE TO PRIOR APPLICATIONS 
     This application is a National Stage Patent Application of PCT International Patent Application No. PCT/KR2017/009396 (filed on Aug. 29, 2017) under 35 U.S.C. § 371, which claims priority to Korean Patent Application No. 10-2016-0110023 (filed on Aug. 29, 2016), which are all hereby incorporated by reference in their entirety. 
    
    
     BACKGROUND 
     The present disclosure relates to a juicer that is easy to manufacture and improves performance, which is easy to assemble, has a low possibility of occurrence of an erroneous assembly, and has improved operation performance. 
     In general, a juicer is a machine for extracting juice by squeezing materials such as various vegetables or fruits and includes a centrifugal separation type and a twin gear type. The centrifugal separation type is suitable as a juicer for extracting fruit juice such as fruits, but there was a problem in that a juice extraction rate is not very high even if the vegetable having fiber-rich and low water content is cut at a very high-speed rotation for extracting juice. On the contrary, the twin gear type is a configuration of cutting and squeezing the materials or cutting and squeezing simultaneously the materials to extract juice, and has an advantage in that the juice extraction rate is several times higher than that of the centrifugal separation type, such that most of the juice market demand is currently occupied by the twin gear type juicer. 
     The twin gear type juicer includes a pair of crushing parts in the form of helical gear and a pair of conveying parts in the form of an Archimedes spiral, and the crushing part and the conveying part are accommodated in a housing in which a juice netting is formed, and then the housing and a driving part are coupled to each other through a fastening part. The pair of crushing parts are driven by the driving part and rotated while interlocking with each other to crush and juice the injected materials to convey it to the conveying part, and the conveying part may convey and squeeze the crushed materials to thereby extract the juice from the materials. The fastening part is configured to include two arms each having a semicircular cross section hinged to one end of the driving part, a lever hinged and extended to the tip of one arm, and a link each hinged between the tip of the other arm and the middle of the lever. 
     As illustrated in  FIGS. 1 and 2 , the juicer is composed of a driving part  100 , a juice part  200  connected to the driving part  100  by a fastening part  300  to juice the juice, and the fastening part  300  for connecting the juice part  200  to the driving part  100 . 
     The driving part  100  is composed of a hollow housing  110  and a motor  150  provided in the housing  110 . The housing  110  is provided with a hollow first connection part  130  formed in the shape that is protruded forwardly and increases in diameter forwardly toward the longitudinal direction thereof and decreases again on the end portion thereof. 
     The housing  110  is composed of a lower housing  113  opened upwardly and recessed, and an upper housing  111  opened downwardly and coupled to the upper portion of the lower housing  113  to form a hollow part  110   a  therein. The lower housing  113  and the upper housing  111  are coupled to each other so that the opened portions thereof face each other, and the housing hollow part  110   a  is formed therein. The housing  110  may be made of metal or plastic. 
     The upper end portion of the lower housing  113  is inserted into the lower end portion of the upper housing  111 , and a fastening screw  115  is fastened through the lower end portion of the upper housing  111  and the upper end portion of the lower housing  113  at one or more positions along the circumference thereof. 
     The motor  150  is installed in the housing hollow unit  110   a  formed by the lower housing  113  and the upper housing  111 . The housing hollow unit  110   a  is provided with a plate-shaped first bracket  121  that is disposed at the rear thereof, is coupled to the bottom portion of the lower housing  113 , and has a shape extended in the width direction thereof, and is provided with a second bracket  125  that is spaced apart from the first bracket  121  forwardly to be coupled to the lower housing  113 . The first bracket  121  and the second bracket  125  may also be coupled and installed to the upper housing  111 . The first bracket  121  and the second bracket  125  have a bent structure for increasing stiffness. 
     In  FIGS. 1 and 3 , reference numeral  151  refers to a connection bracket provided at the front of the motor  150  and having the front end portion inserted into the second bracket  125 . 
     The motor  150  is inserted into the motor housing  160 . The motor housing  160  is formed in a shape opened forwardly. The motor housing  160  has a hollow downward extension part  169  extended downwardly and having the end portion opened. The motor housing  160  has a step portion  161   a  to which the rear end portion of the motor  150  inserted into the motor housing  160  is inserted and seated formed on the rear thereof. A motor housing support protrusion  163  protruded inwardly is provided on the opened front end portion of the motor housing  160 , and a motor housing extension part  165  protruded forwardly from the support protrusion  163  is provided. The support protrusion  163  protrudes inwardly from the motor housing extension  165  to form a forwardly facing motor housing step part. 
     The motor  150  is inserted from the front thereof into the motor housing  160 , and the rotation shaft of the motor  150  is projected forwardly. 
     The motor housing  160  is interposed between the first bracket  121  and the second bracket  125 . The second bracket  125  is formed in a structure in which a center portion thereof is perforated so that the rotation shaft protruded forwardly or a drive shaft (not illustrated) connected to the rotation shaft may pass through. 
     In  FIG. 2 , reference numeral  123  refers to a fixing screw for fixing the motor  150  to the first bracket  121 , and  127  to a fixing screw for fixing the second bracket  125  to the housing  110 . 
     The motor  150  is inserted into the second bracket  125  toward the motor housing  160  to be supported by the second bracket  125 . 
     A circular through-hole  113   b  is formed in the bottom of the lower housing  113  about at the central portion thereof. A cooling fan  170  is installed on the bottom of the lower housing  113  so as to be disposed on the upper portion of the through-hole  113   b  of the lower housing  113 . When the cooling fan  170  is operated, the air is exhausted downwardly through the through-hole  113   b  of the lower housing  113 . 
     As illustrated in  FIG. 6 , the cooling fan  170  is disposed within the downward extension part  169  of the motor housing  160 . When the cooling fan  170  is operated, the air in the motor housing  160  flows downwardly along the downward extension part  169  and is discharged through the cooling fan  170  and 1 mm mesh) may be installed between the cooling fan  170  and the bottom of the lower housing  113 . In  FIG. 2 , reference numeral  111   a  refers to a communication hole formed in plural on the rear of the upper housing  111  so that the air is communicated inwardly and outwardly. 
     As illustrated in  FIGS. 2 and 4 , the lower housing  113  is provided with a support member  181  having a circular cross section made of urethane rubber, etc. A support member installation hole  113   a  vertically penetrated is formed on the bottom of the lower housing  113 . The support member  181  is provided in contact with the bottom surface of the bottom of the lower housing  113 . The support member  181  is formed with a support member coupling hole  181   b  that forms a downward step portion and vertically penetrates. A support member coupling screw  183  is inserted into the support member coupling hole  181   b  through the support member installation hole  113   a  and the end portion of the support member coupling screw  183  is protruded into the housing hollow part  110   a,  and a coupling nut  185  is fastened to the protruded support member coupling screws  183  to install the support member. A washer  187  is further provided between the coupling nut  185  and the bottom of the lower housing  113 . In  FIG. 4 , reference numeral  181   a  refers to an annular support member reinforcement part installed in the support member installation hole  113   a  to contact with the coupling screw  183 . The juice part  200  is connected to the driving part by the fastening part  300  to be driven. 
     The description of the fastening part  300  and the juice part  200  is well known in the related art and will be omitted herein. 
     There have been problems in that the above-described juice part according to the related art requires a plurality of parts for installing the support member  181 , and the operation for coupling is not simple, and when the lower housing  113  and the upper housing  111  are coupled, the upper housing  111  fell down excessively and the upper end portion of the lower housing  113  was inwardly deformed in contact with the inner surface of the upper housing  111  while falling down excessively, and thereby damage such as scratch occurred on the outer surface of the lower housing  113  by the lower end portion of the upper housing  111 , it was not easy to insert the motor  150  into the motor housing  160 , and the housing  110  was heated by the inner air discharged through the downward extension part  169 . 
     SUMMARY 
     The present disclosure is intended to solve the above problems, and an object of the present disclosure is to provide a juicer that is easy to manufacture and improves performance, which may be easy to assemble, prevent occurrence of defects in a manufacturing process, and suppress overheating of the housing by use. 
     For achieving the object, the present disclosure provides a juicer that is easy to manufacture and improves performance including a driving part composed of a housing having a housing hollow part formed therein and a motor provided the housing hollow part by being surrounded by a motor housing, a juice part connected to the driving part to be driven by the driving part to squeeze the juice, and a fastening part for detachably coupling the juice part to the driving part; the motor housing is composed of an upper motor housing having a shape opened downwardly and a lower motor housing having a shape opened upwardly and coupled to face the upper motor housing to be formed in a shape opened forwardly and backwardly, and is formed with a motor housing opening portion eccentric to one side in the width direction from the central portion thereof to be opened downwardly; a cooling fan for causing downward flow of air by operation is provided in the motor housing opening portion, and the housing is formed with a through-hole that is penetrated vertically so as to be eccentric to one side in the width direction from the central portion thereof to dispose on the lower portion of the cooling fan; and the inner air is discharged by the operation of the cooling fan through the through-hole formed at the position eccentric to one side from the central portion in the width direction thereof. 
     As described above, the lower motor housing has a hollow lower motor housing extension portion, which is extended downwardly at the position eccentric to one side in the width direction from the central portion thereof, provided on the lower portion thereof, and the motor housing opening portion is formed to have the end portion of the lower motor housing extension portion opened; the cooling fan is provided in the lower motor housing extension portion; and a flow guide member penetrated vertically is formed on the lower portion of the cooling fan, and the flow guide member is spaced apart from each other and has a guide member inclined in the direction in which the lower motor housing extension portion has been eccentric, and thereby, the air flowed downwardly by the cooling fan is discharged by diverting to the eccentric direction while passing through the flow guide member. 
     As described above, the motor housing has a guide protrusion, which has a shape parallel with each other, protruded inwardly, and extended in the width direction thereof, spaced in the longitudinal direction thereof to be formed in plural. 
     As described above, the housing is composed of a lower housing having a recess shape opened upwardly and an upper housing having a recess shape opened downwardly and coupled to face the lower housing on the upper portion of the lower housing to form the housing hollow part therein, and the through-hole is formed in the lower housing; a housing coupling part is formed on the lower end portion of the upper housing along the circumference thereof, and the housing coupling part is composed of a first bent portion bent outwardly, an upper housing extension portion extended downwardly from the first bent portion, and a second bent portion having the end portion of the upper housing extension portion formed to be bent inwardly; a lower housing bent portion curved and bent inwardly is formed on the upper end of the lower housing, and a part of the upper end portion of the lower housing is inserted into the housing coupling part; a coupling member is provided between the housing coupling part and the lower housing; the coupling member has a coupling member seating portion curved to contact the lower housing bent portion formed on the inside of the upper portion thereof and thereby has the inside contact with the outer surface of the lower housing and the outer surface of the lower housing bent portion, and has the outside contact with the inner surfaces of the first bent portion, the upper housing extension portion, and the second bent portion; and the end portion of the second bent portion of the upper housing is spaced apart from the outer surface of the lower housing. 
     As described above, the bottom portion of the housing is formed with a plurality of support member installation holes penetrated vertically and spaced apart from each other, and each of the support member installation holes is coupled to a support member; the support member has a support member through-hole penetrated and formed vertically, and is composed of a support member insertion portion, a support member holding portion, and a support member exposure portion; and the support member insertion portion has the outer surface formed to be inclined to reduce the cross-sectional area toward the upper portion thereof, the support member exposure portion is spaced downwardly from the support member insertion portion, and the support member holding portion is provided between the support member insertion portion and the support member exposure portion and is formed to have a cross-sectional area smaller than those of the support member insertion portion and the support member exposure portion so that step surfaces contacting the inner surface and the outer surface of the bottom surface of the housing are formed on the upper portion thereof and the lower portion thereof, respectively. 
     According to the juicer that is easy to manufacture and improves performance, it is possible to manufacture simple and easily, less likely to cause defects in the manufacturing process, and to prevent from being overheated by exhaust during use. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective diagram illustrating a juicer according to the related art. 
         FIG. 2  is a cross-sectional diagram illustrating the juicer according to the related art. 
         FIG. 3  is an enlarged diagram of the portion “B” of  FIG. 2 . 
         FIG. 4  is a cross-sectional diagram illustrating a motor housing provided in the juicer of the related art. 
         FIG. 5  is a diagram illustrating the planar cross section of the motor housing and a cooling fan provided in the juicer of the related art. 
         FIG. 6  is a partial cross-sectional diagram, as the partial enlarged diagram of a part of a juicer according to the present disclosure, corresponding to the portion “A” of  FIG. 2  illustrating for explaining the coupling between an upper housing and a lower housing. 
         FIG. 7  is a partial cross-sectional diagram corresponding to the portion of  FIG. 3  as the partial cross-sectional diagram of a part of the juicer according to the present disclosure. 
         FIG. 8  is a perspective diagram illustrating a lower motor housing constituting the motor housing provided in the juicer according to the present disclosure. 
         FIG. 9  is a perspective diagram illustrating an upper motor housing constituting the motor housing provided in the juicer according to the present disclosure. 
         FIG. 10  is a partial cross-sectional diagram illustrating for explaining an operation of the juicer of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, a juicer according to the present disclosure, which is easy to manufacture and improves performance, will be described in detail with reference to the drawings. In the description, a detailed description of the configurations overlapping with the related art will be omitted. Then, in the following description, it will be described by regarding the lateral direction of  FIG. 2  as a longitudinal direction, and regarding the direction perpendicular to the paper surface of  FIG. 2  as a width direction. 
       FIG. 6  is a partially enlarged diagram of a part of the cross-sectional diagram corresponding to a portion “A” of  FIG. 2  for explaining the coupling between the upper housing and the lower housing,  FIG. 7  is a partially enlarged diagram of a part of the juicer according to the present disclosure, and is a partial cross-sectional diagram corresponding to the portion of  FIG. 3 ,  FIG. 8  is a perspective diagram illustrating a lower motor housing constituting the motor housing provided in the juicer according to the present disclosure,  FIG. 9  is a perspective diagram illustrating an upper motor housing constituting the motor housing provided in the juicer according to the present disclosure, and  FIG. 10  is a partial cross-sectional diagram illustrating for explaining an operation of the juicer according to the present disclosure. 
     Referring to  FIG. 1 , a juicer that is easy to manufacture and improves performance according to the present disclosure is composed of a driving part for driving a juice part, a juice part for squeezing the juice, and a fastening part for detachably connecting the juice part to the driving part as in the related art. 
     In the following description, a description overlapping with the related art will be omitted, and only specific configurations of the present disclosure will be described. 
     The driving part is composed of a hollow housing  510  having a housing hollow part  510   a  formed therein, and a motor inserted into the motor housing and provided in the housing hollow part  510   a.  The juice part is connected to and driven by the rotation shaft of the motor to squeeze the juice. Since a configuration for the juice part is a known technology in the prior art, a detailed description thereof will be omitted. Since explanation of the fastening part for detachably connecting the juice part to the driving part has been described in detail in the related art, a description thereof will be omitted. 
     The housing  510  will be described. 
     The housing  510  may be made of a metal such as stainless steel. 
     The housing  510  is composed of a lower housing  513  that has a plate shape and has a concave shape opened upwardly and an upper housing  511  in a plate shape that has a concave shape opened downwardly and is coupled to the upper portion of the lower housing  513  to face the lower housing  513  to form the housing hollow part  510   a  therein. 
     A housing coupling part is formed on the lower end portion of the upper housing  511  along the circumference thereof. The housing coupling part is composed of a first bent portion  511   a  bent outwardly, an upper housing extension portion  511   b  extended downwardly from the first bent portion  511   a,  and a second bent portion  511   c  having the end portion of the upper housing extension portion  511   b  bent inwardly and formed. The first bent portion  511   a  and the second bent portion  511   c  are formed to be protruded and curved outwardly. 
     A lower housing bent portion  513   d  curved and bent inwardly is formed on the upper end of the lower housing  513 . A part of the upper end portion of the lower housing  513  is inserted into the housing coupling part, and one or more portions thereof penetrate the upper housing extension portion  511   b  and the lower housing  513  sequentially along the circumference thereof to be fastened by the screw. 
     A coupling member  515  is provided between the housing coupling part and the lower housing  513 . The coupling member  515  is extended along the circumference thereof between the housing coupling part and the lower housing  513 . The coupling member  515  is made of an elastic material such as rubber. 
     The coupling member  515  has a coupling member seating portion  515   a  curved to contact the lower housing bent portion  513   d  at the inside of the upper portion thereof, has the inside contact with the outer surface of the lower housing  513  and the outer surface of the lower housing bent portion  513   d,  and has the outside contact with the inner surfaces of the first bent portion  511   a,  the upper housing extension potion  511   b,  and the second bent portion  511   c.  The end portion of the second bent portion  511   c  of the upper housing  511  is spaced apart from the outer surface of the lower housing  513 , and the coupling member  515  is exposed to the bottom thereof between the upper housing  511  and the lower housing  513 . 
     The coupling member  515  has the coupling member seating portion  515   a  contacting the outer surface of the lower housing bent portion  513   d,  and is provided in contact with the first bent portion  511   a  and the second bent portion  511   c,  such that the upper housing  511  is prevented from falling down excessively when the upper housing  511  is coupled to the upper portion of the lower housing  513 , and the outer surface of the lower housing  513  is prevented from being damaged by the end portion of the second bent portion  511   c.    
     The outer surface of the coupling member  515  is adhered to the inner surface of the housing coupling part of the upper housing  511  and the inner surface of the upper housing  511  disposed on the upper portion of the housing coupling part, and has a coupling member protrusion portion  515   c,  which is protruded to be inclined upwardly and inwardly, provided on the upper portion thereof. The coupling member protrusion portion  515   c  is provided in a shape extended to be inclined upwardly and inwardly so as to has the outer surface not contact the upper housing  511  and has the inner surface further protruded than the upper end of the lower housing  513 . The coupling member protrusion portion  515   c  is provided to reliably prevent the upper housing  511  from falling down excessively when the upper housing  511  is coupled to the lower housing  513 . 
     A circular through-hole  513   b  is formed in the bottom portion of the lower housing  513  so as to discharge inner air at a position eccentric to one side in the width direction from a central portion thereof, and a plurality of support member installation holes  513   a  for allowing a support member  581  to be installed are penetrated and formed vertically. 
     The motor housing  560  will be described. The motor housing  560  may be made of synthetic resin such as polyvinyl chloride (PVC). 
     As illustrated in  FIGS. 8 and 9 , the motor housing  560  is composed of an upper motor housing  560   a  and a lower motor housing  560   b  that are coupled to face each other. 
     The lower motor housing  560   b  has an upwardly opened shape and is coupled to face the upper motor housing  560   a,  and has a motor housing opening portion  569   b,  which is downwardly opened at a position eccentric to one side in the width direction from the central portion thereof, on the lower portion thereof. The lower motor housing  560   b  is composed of a lower motor housing body having a substantially semicircular arc-shaped cross section and formed in a shape extended in the longitudinal direction thereof, and a lower motor housing wall provided at both ends of the lower motor housing body in the longitudinal direction. The lower motor housing wall is formed with a lower motor housing first recess  565   b  and a lower motor housing second recess  567   b  that are substantially coaxial with the lower motor housing body and are recess, respectively. The lower motor housing first recess  565   b  is formed on the rear in the longitudinal direction thereof, and the lower motor housing second recess  567   b  is formed on the front in the longitudinal direction thereof. The motor housing opening portion  569   b  is formed in the lower motor housing body. A lower motor housing flange  563   b,  which is extended along the longitudinal direction thereof and is protruded outwardly in the width direction thereof, is provided on both end portions of the lower motor housing body. The lower motor housing flange  563   b  is formed with a plurality of through-holes formed to be spaced along the longitudinal direction thereof. 
     The upper motor housing  560   a  is coupled to face the upper motor housing  560   a  as a downwardly opened shape. The upper motor housing  560   b  is composed of an upper motor housing body having a substantially semicircular arc-shaped cross section and formed in a shape extended in the longitudinal direction thereof, and an upper motor housing wall provided at both ends of the upper motor housing body in the longitudinal direction thereof. The upper motor housing wall is formed with an upper motor housing first recess  565   a  and an upper motor housing second recess  567   a  that are substantially coaxial with the upper motor housing body and are recess, respectively. The upper motor housing first recess  565   a  is formed on the rear in the longitudinal direction thereof, and the upper motor housing second recess  567   a  is formed on the front in the longitudinal direction thereof. An upper motor housing flange  563   a,  which is extended along the longitudinal direction thereof and is protruded outwardly in the width direction thereof, is provided on both end portions of the upper motor housing body. The upper motor housing flange  563   a  is formed with a plurality of through-holes formed to be spaced along the longitudinal direction thereof. 
     The lower motor housing flange  563   b  and the upper motor housing flange  563   a  are provided in contact with each other when the lower motor housing  560   b  and the upper motor housing  560   a  face each other vertically, and a screw is inserted into the through-hole and a nut is fastened to be coupled with each other. 
     The upper motor housing first recess  565   a  and the lower motor housing first recess  565   b  face each other to form an opening on the rear in the longitudinal direction thereof, and the upper motor housing second recess  567   a  and the lower motor housing second recess  567   b  face each other to form an opening on the front in the longitudinal direction thereof. 
     Guide protrusions  561   a,    561   b,  which has a shape parallel with each other, protruded inwardly, and extended in the width direction thereof, are formed on the inner surfaces of the lower motor housing  560   b  and the upper motor housing  560   a  constituting the motor housing to be spaced apart from each other in the longitudinal direction and be formed in plural. It is possible to provide the guide protrusions  561   a,    561   b,  thus increasing the stiffness of the motor housing, and meanwhile, it is possible to guide the air flowing inside to flow in the width direction thereof, thus facilitating the discharge and increasing the cooling effect. 
     The lower motor housing  560   b  has the hollow lower motor housing extension portion  562   b,  which is extended downwardly at a position eccentric to one side in the width direction from the central portion thereof, provided on the lower portion thereof. The motor housing opening portion  569   b  is formed by opening the end portion of the lower motor housing extension portion  562   b.  The lower motor housing extension portion  562   b  is disposed on the upper portion of the through-hole  513   b  of the lower housing  513 . 
     The cooling fan  170  is provided in the lower motor housing extension portion  562   b.  The cooling fan  170  is coupled to the lower housing  513  so as to be disposed on the upper portion of the through-hole  513   b  of the lower housing  513 . 
     A flow guide member  590  is provided on the lower portion of the cooling fan  170 . The flow guide member  590  may also be inserted into the through-hole  513   b,  and may also be provided between the cooling fan  170  and the lower housing  513  so as to be disposed on the upper portion of the through-hole  513   b.  The lower end of the lower motor housing extension portion  562   b  is provided in contact with the inner surface of the lower housing  513 . The flow guide member  590  is provided with a plurality of guide members  591  that are spaced apart from each other in the width direction thereof and have the lower ends inclined so that the lower motor housing extension portion  562   b  is oriented in the eccentric direction, and thereby, the air that has been downwardly flowed by the cooling fan  170  is diverted in an eccentric direction while passing through the flow guide member  590  and is discharged. The discharged air flows in an inclined direction in the eccentric direction, thus reducing the influence on the housing  510  even when it is reflected to the floor where the juicer is placed. 
     The support member  581  will be described. 
     The support member  581  is made of synthetic resin such as urethane rubber having elasticity. 
     The support member  581  is inserted and coupled to the support member installation hole  513   a.  The support member  581  is formed with a support member through-hole  581   b  vertically, and is composed of a support member insertion portion  581 - 1 , a support member holding portion  581 - 3 , and a support member exposure portion  581 - 2  from the upper portion thereof. The support member insertion portion  581 - 1  is formed in a circular cross section and has the outer surface formed to be inclined so that the cross-sectional area reduces toward the upper portion thereof. The support member exposure portion  581 - 2  has a circular cross section and is downwardly spaced apart from the support member insertion portion  581 - 1 . The support member holding portion  581 - 3  is provided between the support member insertion portion  581 - 1  and the support member exposure portion  581 - 2  and is formed to have a cross-sectional area smaller than those of the support member insertion portion  581 - 1  and the support member exposure portion  581 - 2  so that step surfaces contacting the inner surface and the outer surface of the bottom portion of the lower housing  513  are formed on the upper portion thereof and the lower portion thereof, respectively. The cross section of the support member installation hole  513   a  is formed in a circular shape, and the cross section of the support member holding portion  581 - 3  is also formed in a circular shape. 
     The lower end of the support member exposure portion  581 - 2  is protruded downwardly from the lowest outer surface of the bottom portion of the lower housing  513 . 
     According to the juicer that is easy to manufacture and improves performance, it is easy to manufacture, has a low possibility of occurrence of defects in the manufacturing process, and is prevented from being overheated by exhaust during use, and accordingly, it may be used in the industrial field where such demand is present.