Patent Publication Number: US-2012036782-A1

Title: Door Actuator for HVAC System of Vehicle

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application claims priority to Korean Patent Application Number 10-2010-0082919 filed on Aug. 11, 2010, the entire contents of which application is incorporated herein for all purpose by this reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to a door actuator for a heating, ventilating and air conditioning (HVAC) system of a vehicle and, more particularly, to a door actuator for an HVAC system of a vehicle, which includes a change gear unit selectively engaging with a plurality of driving gears, thus allowing a plurality of doors to be actuated by a single motor. 
     2. Description of the Related Art 
     Generally, an HVAC system functions to keep the internal temperature, humidity, and air cleanliness and flow of a vehicle pleasant. The HVAC system has a passage in a casing to guide air blown by a blower. Heat exchangers are provided in the passage to heat or cool the blowing air. Further, several doors are mounted to the HVAC system to distribute the cool or warm air which has been cooled or heated by the heat exchangers to respective portions in the vehicle. 
     Such an HVAC system mainly includes an intake function, a mode function and a temp function. The intake function introduces ambient air into the vehicle or circulates air in the vehicle. The mode function controls the direction of air which flows from a duct of the HVAC system to a vent or a floor. The temp function controls the amount of the cool air that is mixed with the warm air, thus allowing air of a desired temperature to flow into the vehicle. 
     Meanwhile, as shown in  FIG. 5A , a mode door actuator  1  performing the mode function and a temp door actuator  2  performing the temp function are installed, respectively, at a side of an HVAC system  3 , thus actuating a mode door and a temp door. 
     For example, as shown in  FIG. 5B , the conventional door actuator includes a pair of upper and lower casings  10  in which various parts are molded in a predetermined shape, a motor  11  which is provided in the upper and lower casings  10  and rotated forwards or backwards in response to an external signal, a worm gear  12  which is mechanically connected to an end of the motor  11  to control the torque and velocity of the motor  11 , a gear unit G which has a helical gear  13  and spur gears  14  and  15 , and a spur gear  16  which engages with the gear unit G to drive the door. 
     However, the conventional door actuator is problematic in that the mode door actuator for driving the mode door and the temp door actuator for driving the temp door are separately provided on the HVAC system, so that due to the use of the two door actuators, the cost of a product is higher, there are more assembly processes, and space utilization is poor. 
     SUMMARY OF THE INVENTION 
     Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and various aspects of the present invention provide a door actuator for an HVAC system of a vehicle, which is intended to drive a plurality of doors using a single motor. 
     Certain aspects of the present invention provide a door actuator for an HVAC system of a vehicle including a driving motor, an actuating gear, a change gear unit, a solenoid unit, a first driving gear, and a second driving gear. The driving motor has a worm wheel and is accommodated in a casing. The actuating gear has on an outer circumference thereof a worm thread that engages with the worm wheel, with an actuating thread being provided on a surface of the actuating gear. The change gear unit is hinged to the casing and rotatably engages with the actuating thread part. The solenoid unit rotates the change gear unit in a first or second direction. The first driving gear is provided at a predetermined position of the casing to engage with the change gear unit rotating in the first direction. The second driving gear is provided at a predetermined position of the casing to engage with the change gear unit rotating in the second direction. 
     The door actuator may further include a first output gear engaging with the first driving gear and driven to transmit a driving force to a temp door which controls a temperature, and a second output gear engaging with the second driving gear and driven to transmit a driving force to a mode door which controls a direction of wind. 
     The change gear unit may include a main gear hinged to the casing via a rotating shaft and engaging at a first portion thereof with the actuating thread part, a sub gear engaging with a second portion of the main gear, and a rotary member connecting the main gear with the sub gear in such a way that the sub gear rotates about the rotating shaft of the main gear. 
     The solenoid unit may include a solenoid valve which is mounted to a predetermined portion of the casing, and an actuating rod which is connected to the solenoid valve in such a way as to move forwards and backwards and rotates the change gear unit in the first or second direction when the solenoid valve is operated. 
     The door actuator may further include a restraining lever which is hinged at a central portion thereof to the casing to restrain either of the first or second output gear when the change gear unit rotates. 
     The restraining lever may include a hinge member which is hinged at a central portion thereof to the casing, a moving groove which is formed in a first end of the hinge member in such a way as to be operated in conjunction with a rotation of the change gear unit and restrains a rotating part of the change gear unit, and a stopper which is provided on a second end of the hinge member in such a way as to be stopped by either of the first or second output gear when the hinge member rotates. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view showing the construction of an exemplary door actuator for an HVAC system of a vehicle according to the present invention. 
         FIG. 2  is a bottom view showing the door actuator of  FIG. 1 . 
         FIG. 3  is a plan view showing the exemplary door actuator for the HVAC system of the vehicle according to the present invention; 
         FIG. 4A  is a view showing the operation of a first driving gear of the exemplary door actuator for the HVAC system of the vehicle according to the present invention; 
         FIG. 4B  is a view showing the operation of a second driving gear of the exemplary door actuator for the HVAC system of the vehicle according to the present invention; 
         FIG. 5A  is a perspective view showing a conventional HVAC system of a vehicle; and 
         FIG. 5B  is an exploded perspective view showing the construction of the conventional door actuator for an HVAC system of a vehicle. 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to various embodiments of the present invention(s), examples of which are illustrated in the accompanying drawings and described below. While the invention(s) will be described in conjunction with exemplary embodiments, it will be understood that present description is not intended to limit the invention(s) to those exemplary embodiments. On the contrary, the invention(s) is/are intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents and other embodiments, which may be included within the spirit and scope of the invention as defined by the appended claims. 
     As shown in  FIGS. 1 and 2 , a door actuator according to the present invention is provided on an HVAC system to drive a plurality of doors using a single driving motor  100 . 
     To this end, the door actuator includes a driving motor  100 , an actuating gear  200 , a change gear unit  300 , a solenoid unit  400 , a first driving gear  510 , a second driving gear  520 , a first output gear  610 , a second output gear  620  and a restraining lever  700 . First, the main construction of the door actuator will be described in brief. 
     The driving motor  100  provides an actuating force to the actuator via a worm wheel  110 . The worm wheel  110  may be rotated clockwise or counterclockwise, and the door actuator may open or close the door depending on the direction of rotation of the worm wheel  110 . 
     The actuating gear  200  functions to transmit the actuating force from the worm wheel  110  of the driving motor  100  to the change gear unit  300 . To this end, the actuating gear  200  has on its outer circumference a worm thread  210  which meshes with the worm wheel  110 . An actuating thread part  220  is provided on a surface of the actuating gear  200  to engage with the change gear unit  300 . 
     The change gear unit  300  engages with the actuating thread part  220  of the actuating gear  200  to rotate in opposite directions. Such a rotating structure allows the change gear unit  300  to be selectively coupled to the first or second driving gear  510  or  520 . Here, the change gear unit  300  is rotated by the solenoid unit  400 . 
     The solenoid unit  400  pushes or pulls the change gear unit  300 , thus rotating the change gear unit  300 . Preferably, the solenoid unit  400  is placed to be perpendicular to the rotating change gear unit  300 , and rotates the restraining lever  700 , thus restraining the first or second output gear  610  or  620  that will be described below. 
     The restraining lever  700  is rotated in a direction opposite to the rotating direction of the change gear unit  300  by the operation of the solenoid unit  400 . The restraining lever  700  restrains the first output gear  610  when the second output gear  620  is operated, and restrains the second output gear  620  when the first output gear  610  is operated. 
     In order to more clearly explain the above-mentioned construction, the construction according to various embodiments will be described below in detail with reference to the accompanying drawings. 
     As shown in  FIGS. 1 to 3 , the driving motor  100  is mounted on a base such as casing  800  of the HVAC system, and has on its rotating shaft the worm wheel  110  that engages with the actuating gear  200 . The worm wheel  110  is placed perpendicular to the actuating gear  200 , and is connected to the change gear unit  300  via the actuating gear  200  to be driven. One will appreciate that the base may be a casing that houses the driving motor, worm wheel, gears, change gear unit and/or other components such as the illustrated casing  800 . 
     The change gear unit  300  is hinged to the casing  800  via a rotating shaft  301  and rotated by the rotation of the actuating gear  200 . Such a change gear unit  300  includes a main gear  310 , a sub gear  320  and a rotary member  330 . 
     The main gear  310  of the change gear unit  300  comprises a spur gear which is hinged to the casing  800  via the rotating shaft  301 . A portion of the main gear  310  engages with the actuating thread part  220 , so that the actuating force of the actuating gear  200  is transmitted to the main gear  310 . The sub gear  320  comprises a spur gear which engages with another portion of the main gear  310 , and moves along the outer circumference of the main gear  310  when the main gear  310  rotates. The rotary member  330  connects the rotating shaft  301  of the main gear  310  with the rotating shaft of the sub gear  320 , and guides the movement of the sub gear  320  so that the sub gear  320  rotates about the rotating shaft  301  of the main gear  310 . 
     The solenoid unit  400  is installed at a position in the casing  800 , and rotates the change gear unit  300  in opposite directions. To this end, the solenoid unit  400  includes a solenoid valve  410  which is mounted to a portion of the casing  800 , and an actuating rod  420  which is connected to the solenoid valve  410  in such a way as to move forwards and backwards. Preferably, the actuating rod  420  is placed at a side of the change gear unit  300 , so that the front end of the actuating rod  420  is connected to a connection lug  740  of the restraining lever  700  which will be described below. The connection lug  740  has a space (not shown) in which the front end of the actuating rod  420  is movable for the smooth operation of the actuating rod  420 . 
     That is, if the solenoid valve  410  is operated in response to an actuating signal of a control unit (not shown), the actuating rod  420  is moved forwards and backwards relative to the solenoid valve  410  by the operation of the solenoid valve  410 . Here, since the actuating rod  420  is placed at a side of the change gear unit  300 , it may rotate the change gear unit  300  in opposite directions. 
     In various embodiments, the actuating rod  420  is connected to the connection lug  740  of the restraining lever  700 . However, the present invention is not limited to the disclosed embodiments. That is, the actuating rod  420  may be connected to the rotary member  330  of the change gear unit  300  to rotate the rotary member  330  of the change gear unit  300  when the actuating rod  420  moves forwards and backwards. 
     The first driving gear  510  is provided at a position in the casing  800 , and selectively engages with the change gear unit  300  to be rotated. The first driving gear  510  includes on its outer circumference a first driving thread  511  which may engage with the sub gear  320  of the change gear unit  300 . A first driving thread part  512  is provided on a surface of the first driving gear  510  to engage with the first output gear  610 . 
     For example, in the state in which the sub gear  320  engages with the first driving thread  511  by the change gear unit  300  rotating in one direction, when the worm wheel  110  of the driving motor  100  is rotated, the rotating force of the worm wheel  110  is transmitted through the change gear unit  300  to the first driving gear  510 , and the rotating force is transmitted through the first driving thread part  512  of the first driving gear  510  to the first output gear  610 . 
     The second driving gear  520  is provided at a position in the casing  800 , and selectively engages with the change gear unit  300  to be rotated. The second driving gear  520  includes on its outer circumference a second driving thread  521  which may engage with the sub gear  320  of the change gear unit  300 . A second driving thread part  522  is provided on a surface of the second driving gear  520  to engage with the second output gear  620 . 
     That is, after the sub gear  320  engages with the second driving thread  521  of the second driving gear  520  by the change gear unit  300  rotating in the other direction, when the worm wheel  110  of the driving motor  100  is rotated, the rotating force of the worm wheel  110  is transmitted through the change gear unit  300  to the second driving gear  520 , and the rotating force is transmitted through the second driving thread part  522  of the second driving gear  520  to the second output gear  620 . 
     In various embodiments, the first driving gear  510  engages directly with the first output gear  610 , and the second driving gear  520  engages directly with the second output gear  620 . A plurality of spur gears (not shown) may be provided between the first driving gear  510  and the first output gear  610  or between the second driving gear  520  and the second output gear  620 , thus adjusting the rotating force by changing a gear ratio, or changing the rotating direction of the gears. Here, a spur gear is a general spur gear for transmitting a rotating force between gears. A gear rotating direction may be changed using odd or even spur gears. 
     The first output gear  610  is provided at a position in the casing  800  in such a way as to be operated in conjunction with the first driving gear  510 , and transmits a driving force to a temp door which controls the temperature. That is, since the first output gear  610  engages with the first driving thread part  512  of the first driving gear  510 , the rotating force of the first driving gear  510  may be transmitted to the temp door. 
     The second output gear  620  is provided at a position in the casing  800  in such a way as to be operated in conjunction with the second driving gear  520 , and transmits a driving force to a mode door which controls the direction of the wind. That is, since the second output gear  620  engages with the second driving thread part  522  of the second driving gear  520 , the rotating force of the second driving gear  520  may be transmitted to the mode door. 
     In various embodiments, the first output gear  610  is connected to the temp door to actuate the temp door, and the second output gear  620  is connected to the mode door to actuate the mode door. However, the first output gear  610  may be connected to the mode door, and the second output gear  620  may be connected to the temp door as suits the design conditions imposed by the peripheral parts. 
     The first output gear  610  or the second output gear  620  is selectively restrained by the restraining lever  700 . 
     The restraining lever  700  is hinged at its central portion to the casing  800 , and restrains one output gear when the other output gear is operated. In detail, the restraining lever  700  restrains the second output gear  620  when the first output gear  610  is operated by the driving motor  100 , and restrains the first output gear  610  when the second output gear  620  is operated by the driving motor  100 . 
     In order to realize the above operation, the restraining lever  700  may include a hinge member  710 , a moving groove  720 , and a stopper  730 . 
     The central portion of the restraining lever  700  is hinged to the casing  800  via a hinge shaft  701  in such a way that opposite ends of the hinge member  710  are rotated. The moving groove  720  is formed in one end of the hinge member  710  to restrain the rotating shaft of the sub gear  320 . The stopper  730  is provided on the other end of the hinge member  710  and has on its outer circumference a thread so that the stopper  730  is stopped by either the first or second output gear  610  or  620  when the hinge member  710  rotates. 
     Thus, when the sub gear  320  rotates to one side of the casing  800  and engages with the first driving gear  510 , the other end of the restraining lever  700  rotates to the other side of the casing  800 , so that the stopper  730  engages with the second output gear  620 . Meanwhile, when the sub gear  320  rotates to the other side of the casing  800  and engages with the second driving gear  520 , the other end of the restraining lever  700  rotates to one side of the casing  800 , so that the stopper  730  engages with the first output gear  610 . 
     Preferably, in order to smoothly rotate the restraining lever  700 , a spacing distance between the hinge shaft  701  and the moving groove  720  becomes shorter or the moving groove  720  comprises a long groove which extends in the longitudinal direction of the restraining lever  700 . Thereby, when the sub gear  320  rotates, the rotating shaft of the sub gear  320  may move in the longitudinal direction of the restraining lever  700 . 
     The operation of the present invention constructed as described above will be described below. 
     First, as shown in  FIG. 4A , if the solenoid valve  410  is operated so that the actuating rod  420  moves to one side of the casing  800 , the stopper  730  of the restraining lever  700  rotates to the other side of the casing  800  and engages with the second output gear  620 . Simultaneously, the sub gear  320  rotates to one side of the casing  800  and thus engages with the first driving gear  510 . 
     Subsequently, if the worm wheel  110  of the driving motor  100  is rotated, the rotating force of the worm wheel  110  is transmitted through the actuating gear  200 , the main gear  310  and the sub gear  320  to the first driving gear  510 , and the rotating force transmitted to the first driving gear  510  is transmitted to the first output gear  610 , thus driving the temp door that controls the temperature. 
     Meanwhile, as shown in  FIG. 4B , if the solenoid valve  410  is operated so that the actuating rod  420  moves to the other side of the casing  800 , the stopper  730  of the restraining lever  700  rotates to one side of the casing  800  and engages with the first output gear  610 . Simultaneously, the sub gear  320  rotates to the other side of the casing  800  and thus engages with the second driving gear  520 . 
     Subsequently, if the worm wheel  110  of the driving motor  100  is rotated, the rotating force of the worm wheel  110  is transmitted through the actuating gear  200 , the main gear  310  and the sub gear  320  to the second driving gear  520 , and the rotating force transmitted to the first driving gear  510  is transmitted to the first output gear  610 , thus driving the temp door that controls the temperature. 
     As described above, the present invention achieves the following remarkable effects. 
     First, the present invention is advantageous in that a solenoid valve and an actuating rod are arranged in parallel, so that space utilisation is better in comparison with a configuration wherein a solenoid valve and an actuating rod are arranged in series, and the entire length of a casing may be reduced. 
     Second, the present invention is advantageous in that a single motor provided in a door actuator may drive a plurality of doors, so that the manufacturing cost thereof is reduced, the number of assembly processes is reduced, and space utilization is improved. 
     Third, the present invention is advantageous in that it has a simple structure which selectively changes gears using a solenoid valve, thus selectively actuating a plurality of doors, therefore improving the operation feeling and reliability of a product. 
     For convenience in explanation and accurate definition in the appended claims, the terms “upper” or “lower”, “front”, and etc. are used to describe features of the exemplary embodiments with reference to the positions of such features as displayed in the figures. 
     The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teachings. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and their practical application, to thereby enable others skilled in the art to make and utilize various exemplary embodiments of the present invention, as well as various alternatives and modifications thereof. It is intended that the scope of the invention be defined by the Claims appended hereto and their equivalents.