Abstract:
A retractable display apparatus for use in a vehicle includes a main body disposed on a ceiling of the vehicle, a monitor unit rotatably held by the main body, an actuator for generating a driving force, a conversion assembly for perpendicularly converting a transmission direction of the driving force of the actuator, a transmission assembly for driving the monitor unit by transmitting the driving force from the conversion assembly to the monitor unit. The monitor unit is selectively driven to a stored position in a storage space in the main body and an extended position relative to the main body. The actuator is enclosed in the side space of the storage space in the main body. The conversion assembly is enclosed in the side space of the storage space in the main body.

Description:
CROSS REFERENCE TO RELATED APPLICATION  
       [0001]     This application is based on and claims the benefit of priority of Japanese Patent Application No. 2005-323548 filed on Nov. 8, 2005, and No. 2006-204671 filed on Jul. 27, 2006, the disclosure of which is incorporated herein by reference.  
       FIELD OF THE INVENTION  
       [0002]     The present invention generally relates to a display apparatus used in a vehicle.  
       BACKGROUND OF THE INVENTION  
       [0003]     In recent years, an increased number of automotive vehicles are equipped with a so-called “rear seat entertainment system (RSE)” so that occupants in the rear sheet can watch movies, TV programs or the like. The RSE includes a monitor unit that can be unfolded for viewing and can also be folded into a main body for storage. The monitor unit is more viewable when it is installed on a front part of a ceiling of the vehicle. The monitor unit is unfolded from the main body to be in an extended position by a motor that provides driving force for rotating the monitor unit around a rotation axis, and the driving force from the motor is transmitted to the rotation axis of the monitor unit by a train of gears. Therefore, an axis of the motor and the axis of rotation of the monitor unit are arranged in parallel in a front part of the main body of the RSE. Japanese patent documents JP-A-2004-237895 and JP-A-2005-014847 disclose folding/unfolding mechanisms of the monitor unit in the main body of such system.  
         [0004]     However, because of the folding/unfolding mechanisms having the above-described structure in association with the monitor unit, the main body of the RSE has an increased length in a front-rear direction of the vehicle. As a result, the monitor unit unfolded to be in the extended position comes behind the folding mechanism in the main body, thereby being pushed into a relatively rearward position in the vehicle. Further, rearrangement of the folding/unfolding mechanism relative to the monitor unit is difficult, because the axis of the motor has to be arranged in parallel with the axis of rotation of the monitor unit.  
       SUMMARY OF THE INVENTION  
       [0005]     In view of the above-described and other problems, the present disclosure provides a retractable display apparatus that can be positioned in a front part of a vehicle.  
         [0006]     In one aspect of the present disclosure, the retractable display apparatus includes an actuation assembly such as a motor for folding and unfolding a monitor unit in a main body, a conversion assembly for converting a direction of a driving force from the actuation assembly, and a transmission assembly for transmitting the driving force from the conversion assembly to the monitor unit. The actuation assembly and the conversion assembly are positioned laterally in the main body so as to make room for the monitor unit to be installed in a frontward position in the main body. In this manner, the monitor unit is more viewable when unfolded in a space of the vehicle, and the actuation assembly is efficiently housed in the main body.  
         [0007]     In another aspect of the present disclosure, the retractable display apparatus uses a worm gear for transmitting the driving force to the monitor unit. In this manner, an increased amount of torque is applied to the monitor unit, thereby preventing the monitor unit from being displaced from an intended position even when vibration of the vehicle vibrates the monitor unit.  
         [0008]     In yet another aspect of the present disclosure, the retractable display apparatus has the actuation assembly such as the motor or the like that is disposed in the main body in an angle against a height direction of the main body. In this manner, the height of the retractable display apparatus is reduced.  
         [0009]     In still yet another aspect of the present disclosure, the retractable display apparatus uses a combination of large and small gears for increasing a torque of the driving force. In addition, those gears are arranged in a space-efficient manner, thereby enabling the retractable display apparatus to have a smaller package size by reducing both of a longitudinal and a lateral dimensions of the main body. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]     Other objects, features and advantages of the present invention will become more apparent from the following detailed description made with reference to the accompanying drawings, in which:  
         [0011]      FIG. 1  shows an side view illustration of an actuation assembly of a retractable display apparatus in an embodiment of the present disclosure;  
         [0012]      FIG. 2  shows a cross-sectional view of a train of gears in the actuation assembly;  
         [0013]      FIG. 3  shows an expanded cross-sectional view of a, first gear in the train of gears;  
         [0014]      FIG. 4  shows a perspective view of the retractable display apparatus with a monitor unit stored in a storage space;  
         [0015]      FIG. 5  shows a perspective view of the retractable display apparatus with the monitor unit flipped to an extended position;  
         [0016]      FIG. 6  shows a top view of the retractable display apparatus with partial cross sections;  
         [0017]      FIG. 7  shows a perspective view of a lock assembly of the retractable display apparatus;  
         [0018]      FIG. 8  shows a side view of the lock assembly of the retractable display apparatus;  
         [0019]      FIG. 9  shows a block diagram of a car navigation system in the present disclosure; and  
         [0020]      FIG. 10  shows a flowchart of a close operation process of the retractable display apparatus. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0021]     Embodiments of the present invention are described with reference to the drawings. Like parts have like numbers in each of the embodiments.  
         [0022]     A retractable display apparatus is disclosed as a navigation system in the present embodiment.  
         [0023]      FIG. 9  shows a block diagram of the navigation system  1 . The navigation system  1  includes a position detector  2  with a GPS receiver for determining a current position of a vehicle based on a GPS signal installed therein, a map data input unit  3  for retrieving map data and facility data from information medium such as a hard disk or the like, a media player  4  for retrieving image data and sound data from a DVD-ROM or the like, a front monitor  5  to be viewed by occupants in front seats of the vehicle, and a back monitor  6  to be viewed by occupants in seats of the vehicle. The front monitor  5  and the back monitor  6  are used to display travel information such as a road map, a navigation route, a facility, and/or an image of an entertainment program recorded on the DVD-ROM.  
         [0024]     The front monitor  5  is installed in an instrument panel, and is used to display the travel information and/or images for a driver of the vehicle. The back monitor  6  is installed on a ceiling of the vehicle, and is used to display the images for the occupants of the back seats as a rear seat entertainment system (RSE). The front monitor  5  includes a monitor unit  7  that uses a liquid crystal display unit and an operation unit  8  for input operations. The back monitor  6  includes a monitor unit  9  that uses the liquid crystal display unit, a receiver  11  for receiving a signal from a remote controller  10 , an actuation assembly  12  for opening and closing the monitor unit  9 , a lock assembly  13  for locking the monitor unit  9 , and a control unit  14  that controls operation of the actuation assembly  12  and the lock assembly  13 .  
         [0025]     The position detector  2 , the map data input unit  3 , the media player  4 , the front monitor  5 , and the back monitor  6  are coupled with a control unit  15  of the navigation system  1  that controls display operation on those components. The control unit  15  includes a CPU  16  that provides computing function, and receives signals from the position detector  2 , the map data input unit  3 , and the media player  4  through an interface (I/F)  17 ,  18 ,  19 .  
         [0026]     The control unit  15  also includes video RAMs (VRAMs)  21 ,  22  for storing image data, and image output units  23 ,  24  for outputting the image signal after converting the image data in the VRAMs  21 ,  22 . The monitor units  7 ,  9  in the front/back monitor  5 ,  6  display image based on the image signal from the image output units  23 ,  24 .  
         [0027]     The control unit  15  further includes a sound signal output unit  25  that controls conversion of sound data of the travel information and output of guidance voice based on the travel information from an audio system including an amplifier/a speaker or the like.  
         [0028]     The control unit  15  in the navigation system  1  receives various instruction inputs from users that controls the operation unit  8  in the front seats and/or the remote controller  10  in the back seats. The CPU  16  in the control unit  15  conducts a calculation operation, displays the travel information, road map, guidance image and/or control menus for setting a destination or for setting system configuration or the like on the monitor units  7 ,  9  based on the inputted instructions. Further, the CPU  16  controls output of control signals from the sound signal output unit  25  for the guidance voice that guides the travel information, setting operations or the like.  
         [0029]      FIG. 6  shows a top view of the retractable display apparatus with partial cross sections included therein. The retractable display apparatus is used as the back monitor  6  in the present embodiment, and has a body  26  and the monitor unit  9  housed in a storage space  26   a . The monitor unit  9  opens and closes from/to the storage space  26   a  upon receiving instructions on the remote controller  10  from the user.  
         [0030]     The back monitor  6  has the actuation assembly  12  in a side space of the storage space  26   a . The actuation assembly  12  is used to open/close the monitor unit  9 . The back monitor  6  also has the lock assembly  13  in a rear space of the storage space  26   a.    
         [0031]      FIG. 1  shows a side view illustration of the actuation assembly  12  of the back monitor  6 . The actuation assembly  12  includes a flip actuator  27 , a worm gear  28 , and a gear train  29 . The flip actuator  27  is disposed on a plane that is perpendicular to an axis  9   a  of the monitor unit  9 , and is positioned in an angle against a height direction of the body  26  of the back monitor  6 . The flip actuator  27  has a worm  28   a  on its shaft, and the worm  28   a  engages a worm wheel  28   b  that is a part of the gear train  29 . Rotation of the worm wheel  28   b  is transmitted to rotate the axis  9   a  with an increased torque through the gear train  29 . Material used to make the worm gear  28  and the gear train  29  is a polyacetal (i.e., polyoxymethylene:POM) that is qualified to endure the vibration of the vehicle.  
         [0032]     The flip actuator  27  rotates in a normal direction to swingingly raise the monitor unit  9  from a stored position in the storage space  26   a  (refer to  FIG. 4 ) to an extended position (refer to  FIG. 5 ), and also rotates in a reverse direction to swing back the monitor unit  9  from the extended position to the stored position. The CPU  16  detects a position of the monitor unit  9  by a position sensor (not shown in the figure), and controls the flip actuator  27  based on the detected position of the monitor unit  9 .  
         [0033]      FIG. 2  shows a cross section of the gear train  29 . The gear train  29  includes the worm wheel  28   b , a first to fifth gears  101  to  105 , and a monitor gear  106 . The first gear  101  is integrally formed with the worm wheel  28   b . As the worm wheel  28   b  rotates, the first to fifth gears and the monitor gear  106  rotate. As a result, the monitor unit  9  combined with the monitor gear  106  rotates back and forth according to the rotation of the worm wheel  28   b.    
         [0034]     Each of the first to fourth gears  101  to  104  is a combination of two flat gears. Two flat gears in each of the first to fourth gears  101  to  104  have respectively different diameters, that is, a small and a large gears are combined to form each of the four gears. The first to fourth gears  101  to  104  are engaged with each other in a small to large coupling in order. That is, the small gear of the first gear  101  drives the large gear of the second gear  102 , and the small gear of the second gear  102  drives the large gear of the third gear  103 . In this manner, the torque of the rotation generated by the flip actuator  27  is amplified to drive the monitor gear  106 .  
         [0035]     The first gear  101  in the gear train  29  is a combination of two gears, that is, a first clutch gear  111  that includes the worm wheel  28   b  as the large gear, and a second clutch gear  112  that includes a flat gear  112   a  as the small gear. The second to fourth gears  102  to  104  respectively includes large gears  102   a  to  104   a , and small gears  102   b  to  104   b . The fifth gear  105  is the flat gear.  
         [0036]     The first to third gears  101  to  103  in the gear train  29  are arranged in a staggered manner in a longitudinal direction of the vehicle, that is, the engagement of the small and the large gears alternates sides in order. Therefore, the actuation assembly  12  has a reduced size in both of the lateral and the longitudinal directions.  
         [0037]     The first gear  101  has a clutch mechanism installed therein as shown in  FIG. 3 . The clutch mechanism in the cross-sectional view in  FIG. 3  has a clutch shaft  107  having a flange  107   a  on one end, and the clutch shaft  107  holds an E ring  108 , a clutch washer  109 , a clutch plate  110 , the first clutch gear  111 , and the second clutch gear  112  in order. The second clutch gear  112  is a cylinder having a bottom on one end. An outer periphery of the flange  107   a  of the clutch shaft  107  is rotatably supported by an opening  112   b  of the cylinder in the second clutch gear  112 . An outer surface of the first clutch gear  111  has the worm wheel  28   b  of the warm gear  28 . An outer surface of the second clutch gear  112  has the flat gear  112   a . The first clutch gear  111  is bound by the clutch plate  110  and the second clutch gear  112  with a layer of a felt  113  interposed therebetween. The second clutch gear  112  is pressed against the first clutch gear  111  by a spring compressed between an inner bottom of the cylinder of the second clutch gear  112  and the flange  107   a  of the clutch shaft  107 . In this manner, a predetermined amount of friction is applied to the first clutch gear  111  by the clutch plate  110  and the second clutch gear  112 .  
         [0038]     The clutch mechanism in the first gear  101  described above is used to rotate the second clutch gear  112  as the first clutch gear  111  (i.e., the worm wheel  28   b ) is driven by the flip actuator  27  with the worm  28   a  engaged therewith. The first clutch gear  111  and the second clutch gear  112  rotate together when a load on the second clutch gear  112  is light. When a heavy load is applied to the second clutch gear  112 , the second clutch gear  112  slips on the first clutch gear  111 . In this manner, the monitor unit  9  is allowed to rotate frontward from the extended position upon application of a pushing force on the monitor unit  9 , thereby protecting the actuation assembly  12  from breakage. Similarly, the actuation assembly  12  is protected when, for example, the monitor unit  9  holds an object in a gap in the course of closing operation into the storage space  26   a  by a driving force of the flip actuator  27 .  
         [0039]     The actuation assembly  12  having the above-described advantage is used to open and close the monitor unit  9  in combination with the flip actuator  27 . The actuation assembly  12  is efficiently housed in a side space of the storage space  26   a  in the present embodiment.  
         [0040]      FIG. 7  shows a perspective view of the lock assembly  13  of the retractable display apparatus. The lock assembly  13  includes a lock actuator  30 , a worm gear  31 , a gear train  32 , and a lock cam  33 . The lock actuator  30  is disposed in parallel with a lateral axis of the body  26 . The lock actuator  30  has a worm  31   a  on its shaft, and the worm  31   a  engages a worm wheel  31   b  disposed on the body  26  to be used as the worm gear  31 . Rotation of the worm wheel  31   b  is transmitted to the lock cam  33  through the lock assembly  13  with an increased amount of torque. The lock cam  33  has a gear on its outer surface, an the gear on the lock cam  33  engages the last gear of the gear train  32 . In this manner, the lock actuator  30  drives the lock cam  33 , and the lock cam  33  holds the monitor unit  9 . More practically, a lock finger  33   a  on one end of the lock cam  33  engages a lock hole  34  in a concave shape on the monitor unit  9 . That is, when the monitor unit  9  is positioned in the storage space  26   a , rotation of the lock cam  33  fastens the monitor unit  9  by engaging the lock finger  33   a  with the lock hole  34  as shown in  FIG. 8 . Material used to make the worm gear  31 , the gear train  32  and the lock cam  33  is a polyacetal (i.e., polyoxymethylene:POM) that is qualified to endure the vibration of the vehicle.  
         [0041]     The lock actuator  30  rotates in the normal direction to release the lock finger  33   a  from the lock hole  34  by driving the lock cam  33  from a lock position to an unlock position, and the lock actuator  30  rotates in the reverse direction to lock the lock finger  33   a  with the lock hole  34 . The control unit  14  detects and determines a position of the lock cam  33  by a position sensor (not shown in the figure).  
         [0042]     The body  26  has an elastic member  35  at a position where a periphery of the lock hole  34  in the monitor unit  9  is abutted. More practically, the elastic member is disposed in the body  26  with its head protruding therefrom. The elastic member  35  is made of elastomer, and a material of the elastic member  35  is carefully chosen to avoid interference with a resin that is used to form the body  26  and the monitor unit  9 .  
         [0043]     The lock assembly  13  is used to lock the monitor unit  9  in the storage space  26   a  in the above-described advantageous manner.  
         [0044]     The operation of the retractable display apparatus is described in the following.  
         [0045]     The control unit  14  executes a close operation of the monitor unit  9  upon receiving a close instruction on the remote controller  10 . The control unit  14  also executes the close operation upon detecting a shut off of an engine of the vehicle when the shut-off of the engine is associated with the close operation in configuration setting.  
         [0046]      FIG. 10  shows a flowchart of a close operation process of the retractable display apparatus, that is, the close operation process of the monitor unit  9  in the back monitor  6  controlled by the control unit  14 . The control unit  14  also controls an open operation of the monitor unit  9 . The description of the open operation is omitted for the brevity of the explanation because it has a reversed order of the steps in the close operation. The monitor unit  9  of the back monitor  6  is raised to be in the extended position at a start of the close operation process as shown in  FIG. 5 .  
         [0047]     In step S 1 , the process in the control unit  14  starts a reverse rotation of the flip actuator  27 . The monitor unit  9  is driven to rotate from the extended position to the stored position according to the rotation.  
         [0048]     In step S 2 , the process determines whether the monitor unit  9  is rotated to the stored position by using the position sensor. That is, the position sensor is turned on when the monitor unit  9  rotates to be in the stored position (step S 2 :YES).  
         [0049]     In step S 3 , the process stops the rotation of the flip actuator  27 . The monitor unit  9  stops rotation in the storage space  26   a.    
         [0050]     In step S 4 , the process in the control unit  14  starts the reverse rotation of the lock actuator  30 . The lock cam  33  is driven by the rotation of the lock actuator  30 , and the lock finger  33   a  in the lock cam  33  presses the lock hole  34  in the monitor unit  9  as the lock cam  33  rotates from the unlock position to the lock position.  
         [0051]     In step S 5 , the process determines whether the lock cam  33  is in the lock position by using the position sensor. That is, the position sensor is turned on when the lock cam  33  rotates to be in the lock position.  
         [0052]     In step S 6 , the process stops the reverse rotation of the lock actuator  30 .  
         [0053]     In the above-described manner, the monitor unit  9  is positioned in the storage space  26   a  with the periphery of the monitor unit  9  held by the lock cam  33  and the elastic member  35 .  
         [0054]     In the present embodiment, an installation of the monitor unit  9  at a front end of the body  26  of the back monitor  6  is realized by arranging the enclosure of the actuation assembly  12  in the side space of the storage space  26   a  in a more efficient manner. Therefore, the visibility of the monitor unit  9  is improved in comparison with the conventional back monitor that has the actuation assembly  12  at the front end of the body.  
         [0055]     In addition, the worm gear  28  is used to drive the monitor unit  9  in combination with the flip actuator  27 . Therefore, the monitor unit  9  is securely held in the extended position and displacement of the monitor unit  9  from the extended position due to the vibration of the vehicle applied to the monitor unit  9  is prevented.  
         [0056]     Further, the actuation assembly  12  uses the gear train  29  arranged in a space efficient manner, thereby enabling the back monitor  6  to have a reduced package size in both of the lateral and longitudinal directions.  
         [0057]     In addition, the flip actuator  27  is disposed in an angle against the height direction of the body  26 , thereby enabling a reduced package size of the back monitor  6  in terms of the height of the body  26 .  
         [0058]     Although the present invention has been fully described in connection with the preferred embodiment thereof with reference to the accompanying drawings, it is to be noted that various changes and modifications will become apparent to those skilled in the art.  
         [0059]     For example, the rotation of the flip actuator  27  may be transmitted by using a bevel gear.  
         [0060]     Further, the actuation assembly  12  may be housed in both sides of the storage space  26   a  in the body  26 .  
         [0061]     Furthermore, the monitor unit  9  unfolded and folded by the actuation assembly  12  may be a different device. For example, a lighting unit may be folded and unfolded in and out from the main body  26  instead of the monitor unit  9  by the actuation mechanism arranged in the above described manner.  
         [0062]     Such changes and modifications are to be understood as being within the scope of the present invention as defined by the appended claims.