Patent Publication Number: US-11022366-B2

Title: Refrigerator

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based on and claims priority under 35 U.S.C. § 119 to Korean Patent Application No. 10-2019-0001142 filed on Jan. 4, 2019 in the Korean Intellectual Property Office, which claims the benefit of Japan Patent Application No. 2018-018649 filed on Feb. 5, 2018, and Japan Patent Application No. 2018-165759 filed on Sep. 5, 2018 in the Japan Intellectual Property Office, the disclosures of which are incorporated by reference herein in their entireties. 
     BACKGROUND 
     1. Field 
     The disclosure relates to a refrigerator. 
     2. Description of Related Art. 
     In a conventional manner, a refrigerator having a drawer has been used. For example, a patent document 1 discloses a refrigerator provided with a refrigerator body having a storage compartment, a drawer opening and closing the storage compartment, and a sliding apparatus sliding the drawer against the storage compartment in an opening and closing direction. 
     The sliding apparatus of the refrigerator disclosed in the patent document 1 is provided with a first rail installed on the refrigerator body and a second rail installed on the drawer. By a drive unit installed on the refrigerator body, the second rail is slid against the first rail in the opening and closing direction. 
     Accordingly, if the first rail and the drive unit are not installed with high precision at the time of manufacturing the refrigerator, the second rail presses the drive unit and an excessive load is applied to the drive unit. Therefore, the high precision assembly is used at the time of manufacturing the refrigerator. 
     Further, even if the first rail and the drive unit are assembled with the high precision, when the positional deviation occurs in the first rail due to the deterioration over time, the second rail presses the drive unit and an excessive load is applied to the drive unit. 
     In addition, the positional deviation of the first rail may also occur when the load applied to the drawer is changed in accordance with the increase or decrease in the amount of things (e.g., food) contained in the drawer. 
     SUMMARY 
     Therefore, it is an aspect of the disclosure to provide a refrigerator having a structure configured to be relatively easily assembled in the manufacturing of the refrigerator and configured to reduce a load applied to a drive unit driving a rail although a position of the rail is displaced with respect to a refrigerator body due to the deterioration over time or the deterioration caused by the change in a weight of things, which are stored in a drawer, in accordance with the increase or decrease in the amount of the things. 
     Additional aspects of the disclosure will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the disclosure. 
     In accordance with an aspect of the disclosure, a refrigerator including a body, a storage compartment disposed inside the body and provided with an opening, a drawer configured to open and close the opening of the storage compartment, and a sliding apparatus configured to slidably support the drawer against the storage compartment and the sliding apparatus includes a first rail installed on an inner wall of the storage compartment, a second rail installed on the drawer and configured to be slidable with respect to the first rail, and a drive unit installed on the first rail and configured to provide a driving force to slide the second rail. 
     The drive unit may be coupled to a lower surface of the first rail. 
     The drive unit may be spaced apart from the inner wall of the storage compartment. 
     The sliding apparatus may further include a power transmission unit configured to transmit a driving force of the drive unit to the second rail. 
     The drive unit may include a housing coupled to the lower surface of the first rail, a drive motor disposed inside the housing, and a drive gear disposed outside the housing and configured to transmit the driving force of the drive motor to the power transmission unit. 
     The first rail may include a first end disposed in a front portion of the storage compartment adjacent to the opening, and a second end disposed in a rear portion of the storage compartment, and the drive gear may be adjacent to the first end. 
     The power transmission unit may include a first rack gear installed on the second rail and configured to engage with the drive gear. 
     The power transmission unit may include at least one elastic member disposed between the first rail and the second rail to press the first rack gear against the drive gear. 
     The first rack gear may be coupled to the second rail to be relatively movable in a. direction perpendicular to a direction in which the drawer opens and closes the opening of the storage compartment. 
     The second rail may include a plurality of holes elongated in a direction in parallel with a direction in which the first rack gear moves relative to the second rail, and the first rack gear may include a plurality of screw members configured to pass through the plurality of holes and configured to be movable along the plurality of holes, respectively. 
     The plurality of holes may include a first hole and a second hole, and the first hole and the second hole may have different lengths in a direction in parallel with the direction the first rack gear moves relative to the second rail. 
     The drive unit may include a receiving portion recessed on an outer surface of the housing and configured to receive the drive gear therein, and a cap coupled to the housing to cover at least one part of the receiving portion. 
     The drive unit may further include a discharging portion configured to communicate with the receiving portion and extend to the lower side from the receiving portion. 
     The first rack gear may be disposed above the drive gear. 
     The sliding apparatus may further include an adjustment unit disposed in a rear side of the power transmission unit to adjust a moving distance of the second rail with respect to the first rail. 
     The adjustment unit may include a second rack gear installed on the first rail, a shaft rotatable supported by the second rail, and an adjustment gear provided both ends of the shaft and configured to engage with the second rack gear. 
     The second rack gear may be disposed above the adjustment gear. 
     The second rack gear may be disposed to be opposite to the first rack gear with respect to the adjustment gear. 
     The sliding apparatus may further include a slide rail disposed between the first rail and the second rail and configured to slide the second rail against the first rail. 
     The storage compartment may include a protruding portion formed such that a part of the inner wall of the storage compartment is protruded toward the opening, and the first rack gear may be disposed above the protruding portion inside the storage compartment. 
     Before undertaking the DETAILED DESCRIPTION below, it may be advantageous to set forth definitions of certain words and phrases used throughout this patent document: the terms “include” and “comprise,” as well as derivatives thereof, mean inclusion without limitation; the term “or,” is inclusive, meaning and/or; the phrases “associated with” and “associated therewith,” as well as derivatives thereof, may mean to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, or the like; and the term “controller” means any device, system or part thereof that controls at least one operation, such a device may be implemented in hardware, firmware or software, or some combination of at least two of the same. It should be noted that the functionality associated with any particular controller may be centralized or distributed, whether locally or remotely. 
     Moreover, various functions described below can be implemented or supported by one or more computer programs, each of which is formed from computer readable program code and embodied in a computer readable medium. The terms “application” and “program” refer to one or more computer programs, software components, sets of instructions, procedures, functions, objects, classes, instances, related data, or a portion thereof adapted for implementation in a suitable computer readable program code. The phrase “computer readable program code” includes any type of computer code, including source code, object code, and executable code. The phrase “computer readable medium” includes any type of medium capable of being accessed by a computer, such as read only memory (ROM), random access memory (RAM), a hard disk drive, a compact disc (CD), a digital video disc (DVD), or any other type of memory. A “non-transitory” computer readable medium excludes wired, wireless, optical, or other communication links that transport transitory electrical or other signals. A non-transitory computer readable medium includes media where data can be permanently stored and media where data can be stored and later overwritten, such as a rewritable optical disc or an erasable memory device. 
     Definitions for certain words and phrases are provided throughout this patent document. Those of ordinary skill in the art should understand that in many, if not most instances, such definitions apply to prior, as well as future uses of such defined words and phrases. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a more complete understanding of the present disclosure and its advantages, reference is now made to the following description taken in conjunction with the accompanying drawings, in which like reference numerals represent like parts: 
         FIG. 1  illustrates a perspective view of a refrigerator according to one embodiment of the disclosure; 
         FIG. 2  illustrates a longitudinal section of a lower portion of the refrigerator according to one embodiment of the disclosure; 
         FIG. 3  illustrates an exploded perspective view of a sliding apparatus installed in the refrigerator according to one embodiment of the disclosure; 
         FIG. 4  illustrates a perspective view showing one side (an opening direction) end of the sliding apparatus installed in the refrigerator according to one embodiment of the disclosure; 
         FIG. 5  illustrates a perspective view showing other side (a closing direction) end of the sliding apparatus installed in the refrigerator according to one embodiment of the disclosure; 
         FIG. 6  illustrates a view showing the sliding apparatus installed on both side walls of the refrigerator according to one embodiment of the disclosure; 
         FIG. 7  illustrates a perspective view of a modified embodiment of a housing of the drive unit according to one embodiment of the disclosure; 
         FIG. 8  illustrates a side view of a modified embodiment of a power transmission unit according to one embodiment of the disclosure; 
         FIG. 9  illustrates a view of a modified embodiment of a slide rail according to one embodiment of the disclosure; and 
         FIG. 10  illustrates a view of a modified embodiment of the sliding apparatus according to one embodiment of the disclosure. 
     
    
    
     DETAILED DESCRIPTION 
       FIGS. 1 through 10 , discussed below, and the various embodiments used to describe the principles of the present disclosure in this patent document are by way of illustration only and should not be construed in any way to limit the scope of the disclosure. Those skilled in the art will understand that the principles of the present disclosure may be implemented in any suitably arranged system or device. 
     Embodiments described in the disclosure and configurations shown in the drawings are merely examples of the embodiments of the disclosure, and may be modified in various different ways at the time of filing of the present application to replace the embodiments and drawings of the disclosure. 
     As illustrated in  FIGS. 1 and 2 , a refrigerator  100  according to one embodiment includes a refrigerator body  10 , a storage compartment R 1  provided inside the refrigerator body  10  and provided with an opening  15 , a drawer  20  slidably coupled to the storage compartment R 1  to open and close the opening  15 , and a sliding apparatus  30  configured to movably support the drawer  20  against the storage compartment R 1 . 
     The refrigerator body  10  has a plurality of storage compartments other than the storage compartment R 1 , and a machine room R 2 , in which a device such as a compressor is provided, is provided at the rear of the storage compartment R 1 . 
     A protruding portion  12  protruding toward an opening direction (front) side is formed in an inner wall  11  which separates the storage compartment R 1  from the machine room R 2 . Therefore, the storage compartment R 1  is formed such that an upper area, on which the protruding portion  12  is not formed, is longer than a lower area, on which the protruding portion  12  is formed, along a direction in which the drawer is slide (hereinafter referred to as a first direction). 
     The drawer  20  has a door plate  21  blocking the opening  15  of the storage compartment R 1 . 
     As illustrated in  FIGS. 3 to 5 , the sliding apparatus  30  includes a pair of first rails  40  provided on respective side walls  13  of the storage compartment R 1 , a pair of second rails  50  provided on the door plate  21  of the drawer  20 , a slide rail  60  disposed between the first rail  40  and the second rail  50  and configured to slide the second rail  50  against the first rail  40 , a drive unit  70  installed on the first rail  40  and a power transmission device  80  configured to transmit a power of the drive unit  70  to the second rail  50 . 
     The first rail  40  is fixed to both side walls  13  of the storage compartment R 1  and elongated in the first direction. The first rail  40  is installed in the upper area of the storage compartment R 1 . One end  40   b  of the rear side of the first rail  40  is disposed above the protruding portion  12 . 
     The first rail  40  includes a fixed portion  41  fixed to the side wall  13  of the storage compartment R 1  and a pair of supporting portions  42  extending from an upper side and a lower side of the fixed portion  41  to a direction perpendicular to the side wall  13 . 
     The drive unit  70  is installed in the first rail  40 . 
     The drive unit  70  includes a housing  71  provided in the first rail  40 , a drive motor (not shown) provided inside the housing  71 , and transmission gears (not shown) configured to transmit a torque of the drive motor (not shown). 
     The housing  71  is provided on a lower surface of a lower supporting portion  42   b  of the first rail  40 . 
     Inside the housing  71 , the drive motor (not shown) and the transmission gears (not shown) configured to transmit a torque of the drive motor (not shown) are installed. 
     A drive gear  72  driving the second rails  50  by receiving the torque from the transmission gears (not shown) is installed on an outer surface of the housing  71 . The drive gear  72  is installed in a concave portion  73  formed on the outer surface of the housing  71  and disposed at one end portion  40   a  on the front side of the first rail  40 . The drive gear  72  is disposed at a position adjacent to the opening  15  of the storage compartment R 1 . 
     The housing  71  is connected to the storage compartment R 1  through the first rail  40  but the housing  71  itself is not directly coupled to the storage compartment R 1 . 
     The housing  71  is spaced apart from the side wall  13  of the storage compartment R 1  and thus spaced apart from the refrigerator body  10  in which a dimension deviation is likely to occur during manufacture of the refrigerator. 
     According to one embodiment, a structure in which the housing  71  is manufactured separately from the first rail  40  and then installed on the first rail  40  has been described. Alternatively, a structure in which the housing  71  and the first rail  40  are integrally formed may be applied. 
     Although not shown, a concave receiving portion is formed on an inner surface of the storage compartment R 1 , particularly, on an inner surface of the side wall  13  that is adjacent to the housing  71  of the storage compartment R 1 . A processor (not shown) including a substrate for controlling the drive motor, which is placed in the housing  71 , may be placed in the receiving portion, and thus it is easy to perform a wiring process that is to be connected to the motor. 
     The second rails  50  are installed to extend in parallel with each other from both sides of the back surface (rear surface) of the door plate  21 . Between the two second rails  50 , a storage case C storing products is supported. 
     The second rail  50  is formed by bending a long plate member by a plurality of times in a longitudinal direction thereof. Particularly, the second rail  50  is bent such that a center line  51 , which faces the first rail  40 , protrudes toward the first rail  40 . The center line  51  protrudes further toward the first rail  40  than an upper line  52   a  and a lower line  52   b.    
     A driving rack gear  81  forming the power transmission device  80  described later is provided on the lower side line  52   b  of the second rail  50 . In a state in which the driving rack gear  81  is installed in the second rail  50 , the driving rack gear  81  is disposed such that teeth of the driving rack gear  81  are directed to the lower side. 
     The driving rack gear  81  is engaged with the drive gear  72  forming the drive unit  70  provided on the first rail  40  and thus the power of the drive motor (not shown) may be transmitted to the second rail  50 . 
     The driving rack gear  81  is installed on the second rail  50  such that a distance between a top land of the teeth of the driving rack gear  81  and a top land of the teeth of the drive gear  72  is 5 mm or less. Accordingly, it is possible to prevent an accident in which the finger is stuck between the driving rack gear  81  and the drive gear  72 . 
     The driving rack gear  81  also includes screw members  54  passing through a plurality of holes  53  formed in the lower line  52   b  of the second rail  50 . 
     Each of the plurality of holes  53  extends in a direction intersecting with the first direction (perpendicular to the first direction in this embodiment). Each of the screw members  54  is configured to be slidable with respect to the plurality of holes  53 . Accordingly, the driving rack gear  81  may slide along the plurality of holes  53  in the direction intersecting (perpendicular to) the first direction. 
     A plurality of elastic members  82  is provided on one surface of the driving rack gear  81  facing a lower step formed by the center line  51  and the lower line  52   b  of the second rail  50 . The driving rack gear  81  is pressed against the drive gear  72  by the elastic member  82 . 
     The power transmission device  80  includes the driving rack gear  81  and the plurality of elastic members  82 . 
     The slide rail  60  includes an outer member  61  fixed to the first rail  40 , an inner member  62  fixed to the second rail  50 , and a middle member  63  disposed between the outer member  61  and the inner member  62 . 
     The middle member  63  is configured to be slidable by a ball  64  provided between the outer member  61  and the inner member  62 . 
     The outer member  61  has a length substantially equal to a length of the first rail  40  in the first direction and is fixed between the supporting portions  42   a  and  42   b  of the first rail  40  by being inserted therebetween. 
     The inner member  62  has a length substantially equal to the length of the first rail  40  in the first direction and is fixed to the center line  51  of the second rail  50 . One end of the rear side of the inner member  62  protrudes further toward the rear of the storage chamber R 1  than the second rail  50 . 
     Since the outer member  61  is a member fixed to the first rail  40  without being slidable on the first rail  40 , it may be assumed that the outer member  61  is contained in the first rail  40 . 
     In the same manner, since the inner member  62  is a member that is fixed to the second rail  50  without being slidable on the second rail  50 , it may be assumed that the inner member  62  is contained in the second rail  50 . 
     That is, the first rail  40  represents a member that does not slide against the refrigerator body  10  among the members forming the sliding apparatus  30 , and the second rail  50  represents a member that does not slide against the drawer  20  forming the sliding apparatus  30 . 
     The ball  64  corresponds to a rolling mechanism  60   a  and the rolling mechanism  60   a  is configured to smoothly slide the second rail  50  against the first rail  40 . 
     The sliding apparatus  30  further includes an adjustment unit  90  configured to adjust a movement distance, which the respective second rails  50  slides against the respective first rails  40 , to be equal to each other. 
     The adjustment unit  90  includes an adjustment rack gear  91  provided on each of the first rails  40 , a shaft  92  supported by both second rails  50 , and an adjustment gear  93  fixed to both ends of the shaft  92  and engaged with the adjustment rack gear  91 . 
     The adjustment rack gear  91  is provided on the upper supporting portion  42   a  of the first rail  40 . In a state in which the adjustment rack gear  91  is installed in the first rail  40 , the adjustment rack gear  91  is disposed such that teeth of the adjustment rack gear  91  are directed to the lower side. 
     The shaft  92  is rotatably supported on each of the rear ends of the inner member  62  protruding from the second rails  50  toward the rear of the storage compartment R 1 . 
     The adjustment gear  93  is fixed to the shaft  92  so that the adjustment gear  93  is not rotatable about the shaft  92 . Each of the adjustment rack gears  91  are configured to engage with the adjustment gear  93  fixed to both ends of the shaft  92 . 
     The teeth of both adjustment rack gears  91  and the teeth of both adjustment gears  93  are arranged so as to have the same pitch. Accordingly, when the shaft  92  is rotated about the inner member  62 , a movement speed of the adjustment gear  93  engaged with the one adjustment rack gear  91  is substantially identical to a movement speed of the adjustment gear  93  engaged with the other adjustment rack gear  91 . 
     The adjustment rack gear  91  is arranged in parallel with the driving rack gear  81  in the vertical direction. Therefore, the top land of the teeth of the adjustment rack gear  91  and the top land of the teeth of the driving rack gear  81  are directed to the lower side. 
     The adjustment gear  93  is disposed between the upper surface of the driving rack gear  81 , which is opposite to the surface on which the teeth of the driving rack gear  81  are formed, and the top land of the teeth of the adjustment rack gear  91 . The adjustment gear  93  is configured to rotate and move on the upper surface of the driving rack gear  81 . 
     One end of the adjustment rack gear  91  and one end of the driving rack gear  81  extend in parallel to each other to be disposed above the protruding portion  12  of the storage compartment R 1 . 
     When the second rail  50  provided on the drawer  20  is engaged with the first rail  40  provided in the storage compartment R 1 , the lower line  52   b  of the second rail  50  faces the entire drive gear  72 . That is, the lower end portion  50   a  of the second rail  50  extends further downward than the lower end portion of the top land of the teeth of the drive gear  72 . Since the drive gear  72  is covered by the second rail  50 , it is possible to prevent the injury caused by the user&#39;s fingers being caught. 
     Next, a sliding operation of the drawer  20  of the refrigerator  100  according to one embodiment will be described. 
     When an open signal is received from an operation portion (not shown) provided on the front side of the drawer  20 , in a state in which the drawer  20  completely closes the storage room R 1 , the drive motor rotates. The torque of the drive motor is transmitted to the drive gear  72  via the transmission gears, and the torque transmitted to the drive gear  72  is transmitted to the second rail  50  through the driving rack gear  81  engaged with the drive gear  72 . Accordingly, the drawer  20  is moved in the first direction with respect to the storage compartment R 1  to open the storage compartment R 1 . When the drawer  20  fully opens the storage compartment R 1 , a detection device (not shown) such as a position sensor detects the opening and when a signal generated by the detection device is transmitted to the processor configured to control the drive motor, the drive motor is stopped by the processor. 
     When a close signal is received, in a state in which the drawer  20  completely opens the storage room R 1 , the drive motor rotates. The torque of the drive motor is transmitted to the drive gear  72  via the transmission gears and the torque transmitted to the drive gear  72  is transmitted to the second rail  50  through the driving rack gear  81  engaged with the drive gear  72 . Accordingly, the drawer  20  is moved with respect to the storage compartment R 1  in a second direction opposite to the first direction. When the drawer  20  fully closes the storage compartment R 1 , a detection device (not shown) such as a position sensor detects the closing and when a signal generated by the detection device is transmitted to the processor configured to control the drive motor, the drive motor is stopped by the processor. 
     According to the configuration described above, during the drawer  20  opens and closes the storage compartment R 1 , a movement speed of one side second rail  50  about the first rail  40  is adjusted to be substantially identical to a movement speed of the other side second rail  50  about the first rail  40  by the adjustment unit  90 , and thus unbalance in both lateral directions (left and right side) of the drawer  20  is reduced. 
     When the drawer  20  is moved in the first direction to open the storage compartment R 1 , the drawer  20  is inclined the front downward by its own weight. At this time, an inclination angle of the drawer  20  increases as the drawer  20  becomes a fully opened state from a fully closed state of the storage compartment R 1 . Due to the inclination of the drawer  20 , the second rail  50 , particularly, the front end side of the second rail  50  adjacent to the opening  15  is inclined downward about the first rail  40 . Accordingly, the driving rack gear  81  installed in the second rail  50  is moved in a direction of pressing the drive gear  72  and an overload condition occurs by the displacement of the engaging position between gears. Therefore, a noise may occur and the driving rack gear  81  or the drive gear  72  may be damaged. 
     However, according to the above configuration, since the elastic member  82  is bent by a pressing force, which is equal to or greater than a certain level, to absorb the movement of the driving rack gear  81  caused by the inclination of the drawer  20 , the engagement between the driving rack gear  81  and the drive gear  72  is constantly maintained and thus the drive gear  72  is not overloaded more than necessary. 
     The first rail  40  is disposed above the protruding portion  12  of the storage compartment R 1  and the one end of the driving rack gear  81  installed on the first rail  40  extends to be disposed above the protruding portion  12 . Further, the drive gear  72  engaged with the driving rack gear  81  is disposed adjacent to the opening  15  of the storage compartment R 1 . This makes it possible to secure a long sliding distance of the drawer  20  with respect to the storage compartment R 1 . 
       FIG. 7  illustrates a perspective view of a modified embodiment of a housing of the drive unit. 
     A housing  71  shown in  FIG. 7  has a groove communicating with a concave portion  73  and extending downward from the concave portion  73 , and a cap  74  being coupled to the housing  71  to cover at least one part of the concave portion  73 . 
     By blocking the concave portion  73  with the cap  74 , only the teeth, which is engaged with a driving rack gear  81  among a drive gear  72 , is exposed to the outside of the housing  71 . A discharging portion  75  configured to allow the concave portion  73  to communicate with the outside of the housing  71  is formed in a lower portion of the cap  74 . 
     According to the above-described structure, since the gear system including the drive gear  72  is hardly exposed to the outside of the housing  71 , it is possible to prevent injuries that may occur when the user&#39;s fingers are caught. In addition, the foreign substance introduced into the concave portion  73  is discharged from the discharging portion  75 , and thus it is possible to prevent the drive unit  70  from being abnormally operated or damaged by the foreign substance. 
       FIG. 8  illustrates a side view of a modified embodiment of a power transmission unit. 
     In the second rail  50  as shown in  FIG. 8 , a plurality of holes  53  configured to couple the driving rack gear  81  to the second rail  50  includes a first hole  53   a  and a second hole  53   b , wherein the first hole  53   a  and the second hole  53   b  have different lengths in a direction in parallel with a direction the driving rack gear  81  moves relative to the second rail  50 . 
     The first hole  53   a  is disposed adjacent to the opening  15  of the storage compartment R 1 , and the second hole  53   b  is disposed adjacent to the rear side of the storage compartment R 1 . The length of the second hole  53   b  is longer than the length of the first hole  53   a.    
     As mentioned above, when the drawer  20  is taken out from the storage compartment R 1 , the door plate  21  side is inclined the front downward by the weight of the drawer  20 . Due to the inclination of the drawer  20 , the second rail  50  is inclined with respect to the first rail  40  and thus the driving rack gear  81  installed on the second rail  50  moves in the direction of pressing the drive gear  72 . As the drawer  20  is more taken out from the storage compartment R 1 , the driving rack gear  81  more moves in the direction of pressing the drive gear  72 . However, by using the above mentioned configuration, it is possible to secure a sufficient long movable range of the driving rack gear  81  so as to relieve the load applied to the drive gear  72  when the drawer  20  is taken out by a relatively long distance. In addition, when the drawer  20  is taken out by a relatively short distance, it is possible to secure a small movable range of the driving rack gear  81  so as to maintain the engagement between the driving rack gear  81  and the drive gear  72 . 
     In another embodiment, the drive gear  72  is provided so as to be movable in a direction, in which the drive gear  72  is in contact with and separated from the driving rack gear  81  (in a direction perpendicular to the first direction), with respect to the housing  71 . The drive unit  70  may include an elastic member (not shown) pressing the drive gear  72  to the driving rack gear  81 . 
     In this case, the housing  71  includes a hole (not shown) through which a rotary shaft (not shown) of the drive gear  72  passes, and the hole is elongated in the direction in which the drive gear  72  is in contact with and separated from the driving rack gear  81 . The rotary shaft is configured to be movable along the hole, and the rotary shaft itself may have elasticity. 
     A structure, in which an entire gear system (not shown) including a drive motor installed inside the housing  71  is pressed upward by the elastic member and the drive gear  72  is pressed by the driving rack gear  81  through the rotary shaft of the drive gear  72  contained in the gear system, may be applicable. 
     In addition, as illustrated in  FIG. 6 , the slide rail  60  according to one embodiment has a structure in which each member  61 ,  62  and  63 , which are manufactured by bending a long plate member to have an approximately “U” shaped cross-section, are combined with each other. 
     Side edges  61   a ,  62   a  and  63   a  extending in the longitudinal direction of the respective members  61 ,  62  and  63  are arranged such that the side edge  63   a  of the middle member  63  is disposed outside the side edge  62   a  of the inner member  62  and the side edge  61   a  of the outer member  61  is disposed outside the side edge  63   a  of the middle member  63 . 
     Further, a ball  64  may be disposed between the side edge  62   a  of the inner member  62  and the side edge  63   a  of the middle member  63 , and between the side edge  63   a  of the middle member  63  and the side edge  61   a  of the outer member  61 , and thus the inner member  62  and the middle member  63  may be slidable. 
       FIG. 9  illustrates a view of a modified embodiment of a slide rail. 
     As illustrated in  FIG. 9 , according to the modified embodiment, the outer member  61  and the inner member  62  are formed by being bent to have the general “U” shaped cross section in the same manner as one embodiment, and the middle member  63  is formed by being bent to have a general “W” shaped cross-section. 
     Side edges  61   a ,  62   a  and  63   a  extending in the longitudinal direction of the respective members  61 ,  62  and  63  are arranged such that the side edge  63   a  of the middle member  63 , which is bent to have the general “V” shaped cross-section, is disposed outside the side edge  62   a  of the inner member  62  and the side edge  61   a  of the outer member  61  is disposed in a groove of the side edge  63   a  of the middle member  63 . 
     Further, a ball  64  may be disposed between the side edge  62   a  of the inner member  62  and the side edge  63   a  of the middle member  63 , and between the side edge  63   a  of the middle member  63  and the side edge  61   a  of the outer member  61 , and thus the inner member  62  and the middle member  63  may be slidable. 
     The slide rail  60  may further include a stopper  65  preventing the respective members  61 ,  62 ,  63  from being separated from each other. 
     The stopper  65  is provided at both ends of the inner member  62  and the middle member  63 , and is provided on one surface of the middle member  63  facing one surface of the inner member  62  and one surface of the inner member  62 . The stoppers  65  provided in the inner member  62  and the middle member  63  are arranged such that the inner member  62  and the middle member  63  interfere with each other in a state in which the inner member  62  moves relative to the middle member  63  by a predetermined length. 
     Further, the stopper  65  is provided at both ends of the outer member  61  and the middle member  63 , and is provided on one surface of the middle member  63  facing one surface of the outer member  61  and one surface of the outer member  61 . The stoppers  65  provided in the outer member  61  and the middle member  63  are arranged such that the outer member  61  and the middle member  63  interfere with each other in a state in which the middle member  63  moves relative to the outer member  61  by a predetermined length. 
     The slide rail  60  may further include a guide groove  66  in which the stopper  65  is inserted and moved. 
     In the above embodiment, the first rail  40  and second rail  50  are connected via the slide rail having three members  61 ,  62  and  63 , and thus the drawer  20  is taken out from the storage compartment R 1  by two stages. However, the drawer  20  may be taken out from the storage compartment R 1  by a single stage by using a single slide rail, or the drawer  20  may be taken out from the storage compartment R 1  by three or more stages by using other type slide rails. 
       FIG. 10  illustrates a view of a modified embodiment of the sliding apparatus. 
     As illustrated in  FIG. 10 , a slide rail  60  includes a guide rail  68  installed in a first rail  40 , and a roller  69  rotatably installed in a second rail  50  and rolled along the guide rail  68 . The roller  69  corresponds to the rolling mechanism  60   a , and the rolling mechanism  60   a  is configured to facilitate the sliding movement of the second rail  50  against the first rail  40 . 
     The guide rail  68  is a member that does not slide against the first rail  40  and the roller  69  is a member that does not slide against the second rail  50 . 
     The second rail  50  is formed in a “L “shape by bending a long plate member along its longitudinal direction and is provided with an installation rail  67  configured to install a driving rack gear  81  on a surface facing the first rail  40 . 
     A drive gear  72  of a drive unit  70  is configured to move in a direction of being in contact or separated from the driving rack gear  81  installed in the installation rail  67 . 
     According to one embodiment, the adjustment gear  93  of the adjustment unit  90  is provided on the drawer  20  side, particularly, on the second rail  50  side, and the adjustment rack gear  91  is installed on the refrigerator body  10  side, particularly, the first rail  40  side, but is not limited thereto. Therefore, the opposite structure may be applicable. That is, the adjustment gear  93  may be provided on the refrigerator body  10  side and the adjustment rack gear  91  may be provided on the drawer  20  side. 
     Both adjustment gears  93  are coupled to the respective shafts  92  so as to be rotatable relative to the refrigerator body  10  and both adjustment rack gears  91  are installed to move with the drawer  20 . 
     By increasing the strength of the portion where the adjustment gears  93  are provided, it is possible to omit the shaft  92  coupled to the both adjustment gears  93 . 
     As is apparent from the above description, according to the proposed refrigerator, it is possible to constantly maintain the quality of the refrigerator since it is possible to be relatively easily assembled in the manufacturing of the refrigerator, and it is possible to reduce a load applied to a drive unit driving a rail although a position of the rail is displaced with respect to a refrigerator body due to the deterioration over time or the deterioration caused by the change in a weight of things in accordance with the increase or decrease in the amount of the things stored in a drawer. 
     Although the present disclosure has been described with various embodiments, various changes and modifications may be suggested to one skilled in the art. It is intended that the present disclosure encompass such changes and modifications as fall within the scope of the appended claims.