Patent Publication Number: US-11041642-B2

Title: Indoor unit of air conditioner

Description:
TECHNICAL FIELD 
     An indoor unit of an air conditioner with a moving front panel. 
     BACKGROUND ART 
     Examples of a conventional indoor unit of an air conditioner include, as described in Patent Literature 1 (JP 2000-234760 A), an indoor unit in which a front panel of a casing moves in a vertical direction and includes a panel drive unit that drives the front panel. 
     SUMMARY OF THE INVENTION 
     Technical Problem 
     In the indoor unit disclosed in Patent Literature 1, when a coupling member that transmits a driving force of the panel drive unit is disposed at a position where the coupling member interferes with air flowing into a heat exchanger in the compact indoor unit, heat exchange performance is reduced. 
     In this way, in an indoor unit of an air conditioner that moves a front panel, there is a need to address a problem how to prevent a reduction of heat exchange performance of the indoor unit caused by a coupling member. 
     Solution to Problem 
     An indoor unit of an air conditioner according to a first aspect includes a casing that has a front panel at a front of the casing and a back surface on a rear of the casing, the back surface being fixed to a wall, a heat exchanger that is housed in the casing and has a U-shaped pipe that returns refrigerant flowing in a longitudinal direction, a panel drive unit that is housed in the casing and generates a driving force that moves the front panel by a movement of the panel drive unit itself, and a coupling member that is disposed behind the front panel, couples the front panel and the panel drive unit, and transmits the driving force from the panel drive unit to the front panel, in which the coupling member is disposed in front of the U-shaped pipe so as to at least partially overlap the U-shaped pipe as viewed from a front. 
     In the indoor unit of the air conditioner, at least a part of the coupling member is disposed so as to overlap the U-shaped pipe as viewed from the front, and a space in front of the U-shaped pipe that hardly contributes to heat exchange performance is effectively utilized. As a result, a reduction of the heat exchange performance of the indoor unit can be suppressed. 
     An indoor unit of an air conditioner according to a second aspect is the indoor unit according to the first aspect, in which the U-shaped pipe includes a first U-shaped pipe disposed at a first end in the longitudinal direction, and a second U-shaped pipe disposed at a second end in the longitudinal direction, and the coupling member includes a first coupling member disposed in front of the first U-shaped pipe so as to at least partially overlap the first U-shaped pipe as viewed from the front, and a second coupling member disposed in front of the second U-shaped pipe so as to at least partially overlap the second U-shaped pipe as viewed from the front. In such a configuration, two spaces in front of the first U-shaped pipe and the second U-shaped pipe are effectively utilized. This can enhance the effect of suppressing the reduction of the heat exchange performance of the indoor unit. 
     An indoor unit of an air conditioner according to a third aspect is the indoor unit of the first or second aspect, in which the panel drive unit includes at least one gear disposed in front of a refrigerant pipe extending from the heat exchanger, and the coupling member rotates in accordance with a movement of the gear. This configuration allows a space in front of the refrigerant pipe to be effectively utilized. The compactness of the indoor unit  1  can be achieved. 
     An indoor unit of an air conditioner according to a fourth aspect is the indoor unit according to the third aspect, in which the gear is disposed at a position where at least a part of the gear does not overlap the heat exchanger as viewed from a side. This configuration makes it easy to design an arrangement of the panel drive unit and the refrigerant pipe. 
     An indoor unit of an air conditioner according to a fifth aspect is the indoor unit according to the third or fourth aspect, in which the gear configures a planetary gear mechanism. With this configuration, when a driving force is generated by a motor, for example, a moving part is easily concentrated near an extension line of a shaft to achieve the compactness of the indoor unit easily. 
     An indoor unit of an air conditioner according to a sixth aspect is the indoor unit according to any one of the third to fifth aspects, further including an electric component box that is housed in the casing and electrically connected to the panel drive unit, in which the gear has a center of the longitudinal direction of the gear, the center being disposed between a center of the longitudinal direction of the heat exchanger and a center of the longitudinal direction of the electric component box. This configuration can make the indoor unit more compact in the longitudinal direction than a configuration in which the center of the gear is disposed on the opposite side of the heat exchanger with the electric component box interposed therebetween. 
     An indoor unit of an air conditioner of a seventh aspect is the indoor unit of any one of the first to sixth aspects, in which the coupling member is a component member of a crank mechanism that converts a rotational movement of the panel drive unit into a reciprocating movement of the front panel that reciprocates between an upper front position and a rear lower position. This configuration allows a use of a small actuator that rotates, such as a motor, for the panel drive unit. Therefore, the compactness can be achieved at a low cost. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a cross-sectional view of an indoor unit that is stopped. 
         FIG. 2  is a cross-sectional view of the indoor unit that is stopped. 
         FIG. 3  is a cross-sectional view of the indoor unit in preparation for operation. 
         FIG. 4  is a cross-sectional view of the indoor unit in operation. 
         FIG. 5  is a perspective view of the indoor unit that is stopped. 
         FIG. 6  is a perspective view of the indoor unit in operation. 
         FIG. 7  is a partially enlarged perspective view showing a structure around a coupling member for driving a front panel. 
         FIG. 8  is a front view showing a heat exchanger and a panel drive unit that are attached to a bottom frame. 
         FIG. 9  is a front view showing the heat exchanger, the panel drive unit, and the coupling member that are attached to the bottom frame. 
         FIG. 10  is a partially enlarged cross-sectional view showing the structure around the coupling member for driving the front panel. 
         FIG. 11  is an exploded perspective view of the panel drive unit. 
         FIG. 12  is a perspective view of the panel drive unit. 
         FIG. 13  is a perspective view showing a sun gear and a planetary gear of the panel drive unit. 
     
    
    
     DESCRIPTION OF EMBODIMENT 
     (1) Overall Configuration 
     As shown in  FIGS. 1 to 4 , an indoor unit  1  of an air conditioner includes a casing  10 , a heat exchanger  20 , a coupling member  40 , and a panel drive unit  50 . The heat exchanger  20  and the panel drive unit  50  are housed in the casing  10 . The indoor unit  1  is wall-mounted, and a back surface  10   b  on a rear of the indoor unit  1  is fixed to a wall. 
       FIGS. 1 and 2  show the indoor unit  1  that is stopped.  FIG. 3  shows the indoor unit  1  preparing for operation.  FIG. 4  shows the indoor unit  1  in operation.  FIGS. 1 and 2  are cross-sectional views of the indoor unit  1  cut at different positions along a plane extending in a front-and-rear direction and in an upper-and-lower direction. 
     The casing  10  has a movable front panel  11  and a fixed upper panel  12  at a front of the casing.  FIGS. 5 and 6  respectively show an appearance of the indoor unit  1  that is stopped and an appearance of the indoor unit  1  in operation. As can be seen from  FIGS. 1 to 6 , when the indoor unit  1  is stopped, the front panel  11  is closed, or in other words, the front panel  11  is in a rear lower position. On the other hand, when the indoor unit  1  is preparing or operating, the front panel  11  is opened, or in other words, the front panel  11  is in an upper front position.  FIG. 7  shows a configuration around the coupling member  40  with the front panel  11  removed from the indoor unit  1 . The coupling member  40  is disposed behind the front panel  11 . 
       FIG. 8  shows the heat exchanger  20  and the panel drive unit  50  that are attached to a bottom frame  16 . The heat exchanger  20  has a U-shaped pipe  25  that returns refrigerant flowing in a longitudinal direction (left and right direction) of the indoor unit  1  at both left and right ends of the heat exchanger  20 .  FIG. 9  shows the coupling member  40  in addition to the configuration shown in  FIG. 8 . As can be seen by comparing  FIGS. 8 and 9 , the coupling member  40  is disposed in front of the U-shaped pipe  25  so as to at least partially overlap the U-shaped pipe  25  as viewed from the front. 
     The panel drive unit  50  includes a motor  51  and a gear  52  (see  FIG. 11 ). The motor  51  generates a driving force that moves the front panel  11  by a rotational movement of the motor itself. The rotational movement of the motor  51  is transmitted to the coupling member  40  through the gear  52  as the driving force for movement. 
     (2) Detailed Configuration 
     (2-1) Casing  10   
     As shown in  FIG. 1 , when the indoor unit  1  is stopped, the front panel  11  is disposed on substantially the same plane as the upper panel  12 . The front panel  11  that is in the rear lower position when the indoor unit  1  is stopped moves to the upper front position shown in  FIG. 3  when the indoor unit  1  is in preparation for operation, whereby the upper panel  12  and the front panel  11  overlap each other as viewed from the front. After the front panel  11  moves to the upper front position, a first horizontal flap  13  that configures a bottom surface  10   d  of the casing  10  when the indoor unit  1  is stopped rotates and moves to an upper front position as shown in  FIG. 4 . 
     As can be seen from  FIG. 5 , the casing  10  has a rectangular parallelepiped shape that is longer in the left and right direction. In the indoor unit  1  shown in  FIG. 5 , the front panel  11  is closed, or in other words, the front panel  11  is in the rear lower position. On the other hand, in the indoor unit  1  shown in  FIG. 6 , the front panel  11  is opened, or in other words, the front panel  11  is in the upper front position. A suction port  4  includes not only an upper suction port  4 A (see  FIG. 7 ) formed on a top surface  10   c  of the casing  10 , but also a front suction port  4 B (see  FIG. 3 ) that is opened by the movement of the front panel  11  to the upper front position when the indoor unit  1  is in operation. 
     The casing  10  houses a filter  15  disposed between the heat exchanger  20  and the suction port  4 . Dust is removed, by the filter  15 , from indoor air that enters the suction port  4  and passes through the filter  15 . The indoor air that has passed through the filter  15  flows into the heat exchanger  20 . The casing  10  houses a fan  90  on a downstream side of the heat exchanger  20 . The fan  90  is, for example, a cross-flow fan that extends to left and right along the longitudinal direction of the heat exchanger  20 . A blow-out passage  17  is formed on the downstream side of the fan  90 . In  FIG. 1  and other drawings, a plurality of blades disposed on a circumference of a partition plate is not shown because the cross-flow fan is cut at the partition plate of the cross-flow fan. 
     A plurality of vertical flaps  19  arranged in the longitudinal direction (left and right direction) is attached to the blow-out passage  17 . The first horizontal flap  13  and a second horizontal flap  14  are attached downstream of the vertical flap  19 . An outlet of the blow-out passage  17  is a blow-out port  5 . The blow-out passage  17  and the bottom surface  10   d  of the casing  10  are configured by the bottom frame  16  made of resin. 
       FIG. 8  shows the heat exchanger  20  and the electric component box  70  that are disposed in the casing  10 . The electric component box  70  is disposed on the right of the heat exchanger  20 , or in other words, closer to the right in the casing  10 . The electric component box  70  incorporates a control unit (not shown) that controls the motor  51 , the fan  90 , and the like. 
     (2-2) Heat Exchanger  20   
     As shown in  FIG. 1 , the heat exchanger  20  can be divided into a front heat exchange section  21  and a rear heat exchange section  22 . An upper part of the front heat exchange section  21  and an upper part of the rear heat exchange section  22  are connected to each other. Due to such a structure of the heat exchanger  20 , the heat exchanger  20  has a Λ shape as viewed from a side. 
     The heat exchanger  20  includes a plurality of metal heat transfer fins  23  disposed side by side in the longitudinal direction, a plurality of metal heat transfer tubes  24  that extends in the longitudinal direction through the plurality of heat transfer fins  23 , the metal U-shaped pipe  25  that connects two of the heat transfer tubes in order to return and flow the refrigerant at an end of the heat exchanger  20 . The U-shaped pipe  25  includes a first U-shaped pipe  25   a  disposed on the right as viewed from the front and a second U-shaped pipe  25   b  disposed on the left as viewed from the front. Further, a plurality of refrigerant pipes  26  is connected to the heat exchanger  20 . The refrigerant flows into the heat exchanger  20  from the outside through the refrigerant pipes  26 , and the refrigerant flows from the heat exchanger  20  to the outside through the refrigerant pipes  26 . 
     (2-3) Coupling Member  40   
     As shown in  FIG. 7 , the coupling member  40  includes a first upper crank  31 , a first lower crank  32 , a first link  33 , a second upper crank  34 , a second lower crank  35 , and a second link  36 . The first upper crank  31 , the first lower crank  32 , and the first link  33  are a first coupling member  41 , and configure a first parallel crank mechanism. The second upper crank  34 , the second lower crank  35 , and the second link  36  are a second coupling member  42  and configure a second parallel crank mechanism. 
     As shown in  FIGS. 8 and 9 , the first upper crank  31 , the first lower crank  32 , and the first link  33  that configure the first parallel crank mechanism of the coupling member  40  do not overlap the heat transfer fins  23  of the heat exchanger  20  at all as viewed from the front. The first upper crank  31 , the first lower crank  32 , and the first link  33  are in a range in which the first U-shaped pipe  25   a  is disposed, in the longitudinal direction as viewed from the front. The second upper crank  34 , the second lower crank  35 , and the second link  36  that configure the second parallel crank mechanism partially overlap the heat transfer fins  23  of the heat exchanger  20  as viewed from the front. The second upper crank  34 , the second lower crank  35 , and the second link  36  also partially overlap the second U-shaped pipe  25   b  as viewed from the front. 
     Therefore, the first upper crank  31 , the first lower crank  32 , and the first link  33  that configure the first coupling member  41  of the coupling member  40  do not disturb a flow of the indoor air flowing to the heat transfer fins  23  of the heat exchanger  20 . Further, the second upper crank  34 , the second lower crank  35  and the second link  36  that configure the second coupling member  42  partially overlap the heat transfer fins  23  but protrude toward the second U-shaped pipe  25   b  as viewed from the front. This suppresses disturbing the flow of the indoor air flowing to the heat transfer fins  23  at a left end of the heat exchanger  20 . In particular, when the front panel  11  is opened, most of the second upper crank  34  and the second lower crank  35  are away from the heat transfer fins  23 . Sufficient indoor air flows to the heat transfer fins  23  on the left end of the heat exchanger  20  similarly to the other parts. 
       FIG. 10  mainly shows the second parallel crank mechanism. The second upper crank  34  of the second parallel crank mechanism is bent in an L shape as viewed from the side. A joint portion  34   a  is formed with a square coupling hole  34   b  into which a metal shaft  100  (see  FIG. 8 ) having a square cross section is fitted. When the motor  51  rotates, the rotational movement of the motor  51  is transmitted to the metal shaft  100  via the gear  52 . Further, the rotational movement of the metal shaft  100  is transmitted to the joint portion  34   a . An inner arm  34   c  extends from the joint portion  34   a . The inner arm  34   c  has a relatively short arm length so as not to collide with the upper panel  12  of the casing  10 , the heat exchanger  20 , and the like in a rotation range of the inner arm  34   c . A direction in which a panel side arm  34   d  extends outward from the inner arm  34   c  is bent upward by about 90 degrees with respect to a direction in which the inner arm  34   c  extends as viewed from the side. The panel side arm  34   d  has an arm length longer than the arm length of the inner arm  34   c  in order to increase a moving distance of the front panel  11 . A shaft  34   e  is provided at a panel side tip of the panel side arm  34   d.    
     The shaft  34   e  of the second upper crank  34  is fitted into a bearing  36   a  provided at an upper end of the second link  36 . The shaft  34   e  can rotate in the bearing  36   a . A main portion  36   b  of the second link  36  extending downward from the bearing  36   a  also serves as an attachment plate to which the front panel  11  is attached. The front panel  11  is fixed to the main portion  36   b  with a pressure sensitive adhesive and/or an adhesive. A bearing  36   c  is provided at a lower end of the second link  36 . 
     A shaft  35   a  of the second lower crank  35  is fitted into the bearing  36   c  of the second link  36 . The shaft  35   a  can rotate in the bearing  36   c . An arm  35   b  extends from the shaft  35   a  of the second lower crank  35  toward a casing body  10   g  in the back. The casing body  10   g  is a part of the casing  10  excluding the front panel  11 . A shaft  35   c  is provided at the other end of the arm  35   b . The shaft  35   c  of the second lower crank  35  is fitted into a bearing  10   j  of the casing body  10   g . The shaft  35   c  of the second lower crank  35  can rotate in the bearing  10   j . That is, the casing body  10   g  serves as a fixed link of the second parallel crank mechanism. 
       FIG. 2  mainly shows the first parallel crank mechanism. The first upper crank  31  of the first parallel crank mechanism is bent in an L shape as viewed from the side. A joint portion  31   a  is formed with a square coupling hole  31   b  into which the metal shaft  100  (see  FIG. 8 ) having a square cross section is fitted. A plurality of teeth  31   f  meshed with the gear  52  is formed on an outer periphery of the joint portion  31   a . When the motor  51  rotates, the rotational movement of the motor  51  is transmitted to the plurality of teeth  31   f  via the gear  52 , and then the first upper crank  31  rotates. At this time, the rotational movement of the first upper crank  31  is transmitted to the metal shaft  100 , and the rotational movement of the metal shaft  100  is transmitted to the joint portion  31   a . An inner arm  31   c  extends from the joint portion  31   a . The inner arm  31   c  has a relatively short arm length so as not to collide with the upper panel  12  of the casing  10 , the heat exchanger  20 , and the like in a rotation range of the inner arm  31   c . A direction in which a panel side arm  31   d  extends outward from the inner arm  31   c  is bent upward by about 90 degrees with respect to a direction in which the inner arm  31   c  extends as viewed from the side. The panel side arm  31   d  has an arm length longer than the arm length of the inner arm  31   c  in order to increase a moving distance of the front panel  11 . In this way, the first upper crank  31  has the inner arm  31   c  and the panel side arm  31   d  having substantially the same shapes as the shapes of the inner arm  34   c  and the panel side arm  34   d  of the second upper crank  34  described above. A shaft  31   e  is provided at a panel side tip of the panel side arm  31   d.    
     The shaft  31   e  of the first upper crank  31  is fitted into a bearing  33   a  provided at an upper end of the first link  33 . The shaft  31   e  can rotate in the bearing  33   a . A main portion  33   b  of the first link  33  extending downward from the bearing  33   a  also serves as an attachment plate to which the front panel  11  is attached. The front panel  11  is fixed to the main portion  33   b  with a pressure sensitive adhesive and/or an adhesive. A bearing  33   c  is provided at a lower end of the first link  33 . 
     A shaft  32   a  of the first lower crank  32  is fitted into the bearing  33   c  of the first link  33 . The shaft  32   a  can rotate in the bearing  33   c . An arm  32   b  extends from the shaft  32   a  of the first lower crank  32  toward the casing body  10   g  in the back. A shaft (not shown) is provided at the other end of the arm  32   b . The shaft of the first lower crank  32  is fitted into a bearing (not shown) of the casing body  10   g . The shaft of the first lower crank  32  can rotate in the bearing of the casing body  10   g . That is, the casing body  10   g  also serves as a fixed link of the first parallel crank mechanism. 
     (2-4) Panel Drive Unit  50   
       FIG. 11  shows the panel drive unit  50  that has been disassembled. The panel drive unit  50  includes a motor  51 , the gear  52 , and a gear box  53 . The gear shown in  FIG. 11  configures a planetary gear mechanism. The planetary gear mechanism shown in  FIG. 11  is a planetary type. The gear box  53  includes a motor support  53   a  and a gear support  53   b . The motor  51  and the gear  52  are fixed to the casing  10  by the gear box  53 .  FIG. 12  shows the panel drive unit  50  that has been assembled. 
     The motor  51  is fixed to the motor support  53   a  of the gear box  53  by screws (not shown) or the like. A sun gear  52   a  is fixed to a shaft  51   a  of the motor  51 . Three planetary gears  52   b  are disposed around the sun gear  52   a , and all the three planetary gears  52   b  are meshed with the sun gear  52   a .  FIG. 13  shows the motor  51 , the motor support  53   a , the sun gear  52   a , and the three planetary gears  52   b  being assembled. 
     The three planetary gears  52   b  are meshed with an internal gear  52   c  formed inside the gear support  53   b . The internal gear  52   c  is fixed, and the three planetary gears  52   b  revolve around the sun gear  52   a  in accordance with a rotation of the sun gear  52   a . Carriers  54   a  and  54   b  are attached to the three planetary gears  52   b . The carriers  54   a  and  54   b  rotate in accordance with the revolution of the three planetary gears  52   b . A gear  52   d  is fixed to the carrier  54   a . Thus, the gear  52   d  rotates in accordance with the revolution of the three planetary gears  52   b . A center axis of the gear  52   d  coincides with a center axis of the internal gear  52   c , a center axis of the sun gear  52   a , and the shaft  51   a  of the motor  51 . Due to such a structure, the moving gear  52  can be concentrated near an extension line of the shaft  51   a  that generates the driving force by the motor  51 . Therefore, the gear  52  can be disposed in a narrow space in front of the refrigerant pipes  26  of the compact indoor unit  1 . The gear  52   d  is meshed with the teeth  31   f  disposed on the outer periphery of the joint portion  31   a  of the first upper crank  31 . 
     As shown in  FIG. 8 , the gear box  53  is disposed in front of the refrigerant pipes  26  extending from the heat exchanger  20 . That is, the refrigerant pipes  26  and the gear box  53  overlap each other as viewed from the front. In this embodiment, the gear box  53  is disposed in front of the refrigerant pipes  26 , and all the plurality of gears  52  is disposed in front of the refrigerant pipes  26 . Further, the two-dot chain lines indicated by reference signs CL 1 , CL 2 , and CL 3  in  FIG. 8  represent a center of the longitudinal direction of the heat exchanger  20 , a center of the longitudinal direction of the electric component box  70 , and a center of the longitudinal direction of the plurality of gears  52 , respectively. As can be seen from  FIG. 8 , the center CL 3  of the longitudinal direction of the gears  52  is disposed between the center CL 1  of the longitudinal direction of the heat exchanger  20  and the center CL 2  of the longitudinal direction of the electric component box  70 . Further, as shown in  FIG. 2 , all the gears  52  are disposed at positions where the gears  52  do not overlap the heat exchanger  20  as viewed from the side. 
     In this way, the gears  52  are disposed in front of the refrigerant pipes  26 , and the space in front of the refrigerant pipes  26  is effectively utilized by the gears  52 . As a result, the compactness of the indoor unit  1  can be achieved. The space that is in front of the refrigerant pipes  26  and does not overlap the heat exchanger  20  as viewed from the side is a triangular prism-shaped space at an upper front corner of the casing  10 . In this embodiment, all the gears  52  are disposed at the positions where the gears  52  do not overlap the heat exchanger  20  as viewed from the side. However, when at least a part of the gears  52  is disposed at a position where the part of the gears  52  does not overlap the heat exchanger  20  as viewed from the side, there is an effect of the easy designing although the degree of the effect is varied. When the gears  52  partially overlap the heat exchanger  20  as viewed from the side, it is easy to make the indoor unit  1  compact. 
     (3) Characteristics 
     (3-1) 
     For example, as described with reference to  FIGS. 8 and 9 , in the indoor unit  1  described above, at least a part of the coupling member  40  is disposed so as to overlap the U-shaped pipe  25  as viewed from the front. In this way, the space in front of the U-shaped pipe  25  is effectively utilized for the arrangement of the coupling member  40 . The space in front of the U-shaped pipe  25  that hardly contributes to heat exchange performance is effectively utilized by the coupling member  40 . The flow of the indoor air sucked into the heat exchanger  20  from the front suction port  4 B is suppressed from being blocked by the coupling member  40 . As a result, a reduction of the heat exchange performance of the indoor unit  1  can be suppressed. 
     (3-2) 
     The coupling member  40  disposed so as to at least partially overlap the U-shaped pipe  25  as viewed from the front includes the first upper crank  31 , the first lower crank  32 , the first link  33  as the first coupling member  41 , and the second upper crank  34 , the second lower crank  35 , and the second link  36  as the second coupling member  42 . At least a part of the first coupling member  41  is disposed in front of the first U-shaped pipe  25   a  so as to overlap the first U-shaped pipe  25   a  as viewed from the front. Further, at least a part of the second coupling member  42  is disposed in front of the second U-shaped pipe  25   b  so as to overlap the second U-shaped pipe  25   b  as viewed from the front. The two spaces in front of the first U-shaped pipe  25   a  and the second U-shaped pipe  25   b  are effectively utilized on both sides of the heat exchanger  20 . This can enhance the effect of suppressing the reduction of the heat exchange performance of the indoor unit  1 . 
     (3-3) 
     In the panel drive unit  50  of the above embodiment, the space in front of the refrigerant pipes  26  is effectively utilized by all the gears  52  disposed in front of the refrigerant pipes  26  extending from the heat exchanger  20 . The compactness of the indoor unit  1  can be achieved. In this embodiment, all the gears  52  are disposed in front of the refrigerant pipes  26 . However, when a part of the gear  52  is disposed in front of the refrigerant pipes  26 , the compactness of the indoor unit  1  can be achieved although the degree of the effect is varied. 
     (3-4) 
     In the above embodiment, all the gears  52  are disposed at positions where the gears  52  do not overlap the heat exchanger  20  as viewed from the side. Thus, the refrigerant pipes  26  need not to be arranged to avoid the gears  52 . This makes it easy to design the arrangement of the panel drive unit  50  and the refrigerant pipes  26  in the compact indoor unit  1 . In this embodiment, all the gears  52  are disposed at the positions where the gears  52  do not overlap the heat exchanger  20  as viewed from the side. However, when a part of the gears  52  is disposed at a position where the part of the gears  52  does not overlap the heat exchanger  20  as viewed from the side, the easy designing of the arrangement of the panel drive unit  50  and the refrigerant pipes  26  can be achieved although the degree of the effect is varied. 
     (3-5) 
     The gears  52  of the above embodiment configure the planetary gear mechanism, and thus the gears  52  as a moving part are concentrated near the extension line of the shaft  51   a  of the motor  51  to achieve the compactness of the indoor unit  1 . In particular, the center CL 3  of the longitudinal direction of the gears  52  disposed in front of the refrigerant pipes  26  is disposed between the heat transfer fins  23  of the heat exchanger  20  and the center CL 2  of the longitudinal direction of the electric component box  70 . Therefore, the effect of the compactness is enhanced. 
     (3-6) 
     As described with reference to  FIG. 8 , the center CL 3  of the longitudinal direction of the gears  52  is disposed between the center CL 1  of the longitudinal direction of the heat exchanger  20  and the center CL 2  of the longitudinal direction of the electric component box  70 . Thus, the indoor unit  1  can be made more compact in the longitudinal direction of the indoor unit  1  than a configuration in which the center of the gears  52  is disposed on the opposite side of the heat exchanger  20  with the electric component box  70  interposed therebetween. 
     (3-7) 
     The coupling member  40  is a component member of a parallel crank mechanism that converts the rotational movement of the panel drive unit  50  into a reciprocating movement of the front panel that reciprocates between the upper front position and the rear lower position. With the coupling member  40  configured as above, a small actuator that rotates such as the motor  51  can be used for the panel drive unit  50 . Therefore, the compactness can be achieved at a low cost. 
     (4) Modifications 
     (4-1) Modification 1A 
     In the description of the above embodiment, the planetary gear mechanism configured by the gears  52  of the panel drive unit  50  is the planetary type. The planetary gear mechanism, however, is not limited to the planetary type, but may be, for example, a solar type or a star type. Further, the mechanism configured by the gears  52  of the panel drive unit  50  is not limited to the planetary gear mechanism. 
     (4-2) Modification 1B 
     In the description of the above embodiment, the coupling member  40  is a component member of the parallel crank mechanism that converts the rotational movement of the panel drive unit  50  into the reciprocating movement of the front panel  11  that reciprocates between the upper front position and the rear lower position. The coupling member  40 , however, may be a component member of another crank mechanism, and is not limited to the parallel crank mechanism. 
     Although the embodiment of the present invention has been described above, it will be understood that various changes in forms and details can be made without departing from the gist and scope of the present invention as set forth in the claims. 
     REFERENCE SIGNS LIST 
     
         
           1  Indoor unit 
           10  Casing 
           11  Front panel 
           20  Heat exchanger 
           25  U-shaped pipe 
           25   a  First U-shaped pipe 
           25   b  Second U-shaped pipe 
           40  Coupling member 
           41  First coupling member 
           42  Second coupling member 
           50  Panel drive unit 
           51  Motor 
           52  Gear 
           70  Electric component box 
       
    
     CITATION LIST 
     Patent Literature 
     Patent Literature 1: JP 2000-234760 A