Patent Publication Number: US-2023139845-A1

Title: Power swivel device of seat for vehicle

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     The present application claims priority to Korea Patent Application No. 10-2021-0145362, filed Oct. 28 2021, the entire contents of which is incorporated herein for all purposes by this reference. 
     TECHNICAL FIELD 
     The present invention relates to a power swivel device for a vehicle seat, and more particularly, to a power swivel device for automatically rotating a vehicle seat by driving a motor. 
     BACKGROUND ART 
     Various components are provided as part of the vehicle seat in order to provide enhanced ride comfort and convenience to a driver or passenger. For example, a seat track device capable of moving a vehicle seat in a front-rear direction according to a body shape of an occupant, a leg rest device for supporting a leg portion of a passenger, and the like are applied. 
     In addition, as electric vehicles become popular in recent years, securing an interior space of a vehicle becomes easy, and as autonomous driving technology is greatly developed, interest in activities other than driving in an indoor space of a vehicle while driving is increasing. 
     Therefore, in addition to a general driving mode, a seat structure for implementing various modes such as a conversation mode between passengers and a relaxation mode is being developed, and a representative example of this is a swivel seat in which a direction of a seat can be freely adjusted. 
     Such a swivel seat is currently mainly applied to a second row of a multi-purpose vehicle, and it is aimed to apply the swivel seat to a driver&#39;s seat on the premise of practical use of fully autonomous driving technology. 
     As illustrated in  FIG.  1   , a power swivel device for a vehicle seat according to prior art is configured that a motor  3  is installed on one side of two plates  1  and  2  coupled to be rotated with each other, and driving gear  4  engaged with an output gear of the motor  3  is fixedly installed on another side. 
     Therefore, when driving the motor  3  in a state where one of the two plates  1  and  2  is fixed to the seat rail and the seat is installed on the other plate, the plate on which the seat is installed is rotated, so that a direction of the seat can be adjusted as desired. 
     However, since the motor  3  is a geared motor provided with a gearbox  3   a  for deceleration, there is backlash between a plurality of gears inside the gearbox  3   a , and backlash also exists between the final output gear of the gearbox  3   a  and the driving gear  4 , thus there is a clearance between the fixed plate and the rotating plate of the swivel device in a rotational direction. 
     Therefore, there was a problem that a flow in a rotational direction occurred in the seat, which not only reduced the stability of the seat, but also generated noise from the seat while the vehicle was driving. 
     DOCUMENT OF RELATED ART 
     Patent Document 
     
         
         Korean Patent Laid-Open Publication No. 10-2019-0048405 (published on May 9 2019) 
       
    
     DISCLOSURE 
     Technical Problem 
     Accordingly, the present invention has been devised to solve the above problems, and the purpose of the present invention is to provide a power swivel device for a vehicle seat in which the stability of the seat is improved and noise generation is prevented by eliminating a clearance in a rotational direction. 
     Technical Solution 
     One embodiment is a power swivel device for a vehicle seat including: a fixed plate fixed to a seat rail of an interior floor of a vehicle; a rotating plate rotatably installed on the fixed plate and mounted to a seat; a motor installed on a side of the fixed plate; and a brake unit installed between the fixed plate and the rotating plate, delivering rotational force of the motor to the rotating plate when the motor is operated, and constraining a flow in a rotational direction of the rotating plate when the motor is stopped. 
     A circular guide part is formed to protrude upward on the fixed plate, a circular guide part is formed to protrude downward on the rotating plate, and the guide part of the fixed plate surrounds an outside of the guide part of the rotating plate to constrain a radial flow between the fixed plate and the rotating plate. 
     The brake unit includes: a drum housing and a housing cover coupled to each other to form a part installation space therein; a brake plate installed between the drum housing and the housing cover, having a plurality of wedge bosses formed on an outer circumferential surface and having a wedge surface forming a low inclination toward the wedge boss and a high inclination on an opposite side thereof on both sides of the wedge boss; a wedge roller provided between the wedge surface and an inner circumferential surface of the drum housing to constrain rotation of the brake plate by being sandwiched between the wedge surface and the inner circumferential surface of the drum housing when the brake plate rotates; and an elastic member installed inside a wedge groove formed on a side surface of the wedge boss to push the wedge roller upward from the wedge surface. 
     A plurality of bolts are provided on one side of the brake plate, the bolts are exposed to an outside through an inner diameter section of the drum housing, and the bolts are tightened to a mounting part of the rotating plate. 
     A driving plate is provided between the brake plate and the housing cover, and operating pieces are disposed respectively between the wedge bosses on an outer circumferential surface of the driving plate, and coupling pieces protruding outward through an inner diameter section of the housing cover are formed on an inner circumferential surface of the driving plate, and the coupling pieces are inserted into and welded to the inner diameter section of a driving gear located outside the housing cover. 
     Bolt tightening portions abutting each other on outer circumferential surfaces of the drum housing and the housing cover are formed to protrude, and the bolt tightening portions are bolted to a mounting part of the fixed plate. 
     A circumferential surface portion is formed between the wedge surfaces on both sides between the wedge bosses adjacent to each other of the brake plate, and the operating pieces of the driving plate is formed in an arc shape having the same curvature as the circumferential surface portion, and is in contact with the circumferential surface portion. 
     A mounting plate is installed at a gap to a bottom of the fixed plate, a motor is mounted on the mounting plate, and an output gear of the motor is engaged with the driving gear of the brake unit. 
     Advantageous Effect 
     According to the present invention as described above, the brake unit is installed between the fixed plate and the rotating plate of the swivel device, so that a flow in a rotational direction does not occur between the fixed plate and the rotating plate. 
     Therefore, a flow in a rotational direction does not occur in the seat, so the stability of the seat is improved, and noise according to a flow in a rotational direction of the seat is not generated during driving. 
     As described above, the stability of seat fixation is improved, and noise is not generated, thereby emotional quality of a seat is improved. 
    
    
     
       DESCRIPTION OF DRAWINGS 
         FIG.  1    is a perspective view of the power swivel device according to prior art. 
         FIG.  2    is a perspective view of the power swivel device according to the present disclosure. 
         FIG.  3    is an exploded view of the power swivel device according to the present disclosure. 
         FIG.  4    is a top perspective view of the brake unit, which is a main component of the present disclosure. 
         FIG.  5    is a bottom perspective view of the brake unit. 
         FIG.  6    is an exploded view of the brake unit. 
         FIG.  7    is a partial enlarged view of the brake unit, and (a) is a brake plate in a fixed state, while (b) is a brake plate in a released state. 
     
    
    
     DETAILED DESCRIPTION 
     A variety of modifications may be made to the present invention and there are various embodiments of the present invention, examples of which will now be provided with reference to drawings and described in detail. However, the present invention is not limited thereto, although the exemplary embodiments can be construed as including all modifications, equivalents, or substitutes in a technical concept and a technical scope of the present invention. In the drawings, the thicknesses of lines illustrated in the accompanying drawings and dimensions of elements may be exaggerated for clarity and convenience. 
     The following terms are defined considering functions of the disclosure, and may be changed according to the intent of users or operators, or conventional practice. Therefore, the terms will be defined throughout the content of this description. 
     Hereinafter, exemplary embodiments will be fully described with reference to the accompanying drawings. 
     As illustrated in  FIGS.  2  and  3   , a power swivel device for a vehicle seat according to the present disclosure includes: a fixed plate  10  fixed to a seat rail of an interior floor of a vehicle; a rotating plate  20  rotatably installed on the fixed plate and fixed to a lower part of a seat; a brake unit  30  installed between the fixed plate  10  and the rotating plate  20  and preventing a flow of the rotating plate  20  in a rotational direction, and a motor  40  installed on a side of the fixed plate and delivering rotational force to the rotating plate  20 . 
     The fixed plate  10  has an approximately rectangular shape and is fixed to an upper rail of a seat rail installed on a floor of a vehicle. A circular through hole  11  is formed in a center of the fixed plate  10  so that a driving gear of the brake unit  30  can protrude downward, and a mounting part  12  for mounting the brake unit  30  around the through hole  11  is formed. 
     The mounting part  12  is a circumferential portion of the through hole  11  and a plurality of bolt holes are formed to mount bolt tightening portions formed on a circumference of the brake unit  30 . 
     In addition, on an upper surface of the fixed plate  10 , a circular guide part  13  concentric with the through hole  11  and the mounting part  12  is formed around the mounting part  12 . The guide part  13  is made of a multi-stage curved surface and is formed to protrude upward of the fixed plate  10  as a whole. 
     The rotating plate  20  is fixedly mounted to a lower part of the seat and is a rectangular plate-shaped part with a shape and area similar to that of the fixed plate  10 . 
     A circular through hole  21  is also formed in a center of the rotating plate  20 , and a mounting part  22  in which a plurality of bolt holes are formed in a circumference of the through hole  21  is formed in the rotating plate  20 . The brake plate of the brake unit  30  is bolted to the mounting part  22  of the rotating plate  20 . 
     Also, on the rotating plate  20 , a circular guide part  23  concentric with the through hole  21  and the mounting part  22  is formed in a circumference of the mounting part  22 . The guide part  23  of the rotating plate  20  also has a multi-stage curved surface, but is formed to protrude downward of the rotating plate  20  in response to the guide part  13  of the fixed plate  10 . 
     When the guide part  13  of the fixed plate  10  is formed with a larger diameter than that of the guide part  23  of the rotating plate  20 , and the fixed plate  10  and the rotating plate  20  are assembled through the brake unit  30 , the guide part  13  of the fixed plate  10  is designed to wrap the guide part  23  of the rotating plate  20  from the outside thereof. 
     Therefore, when the seat swivel is operated, the rotating plate  20  may be rotated smoothly with respect to the fixed plate  10  without interference, and even when a large impact is applied to the seat due to a collision accident, etc., the guide parts  13  and  23  constrain the fixed plate  10  and the rotating plate  20  in a radial direction so that the seat is not separated from the mounting position. 
     The brake unit  30  serves to assemble the rotating plate  20  to the fixed plate  10  with the rotating plate  20  in a rotatable state, deliver rotational force of the motor  40  to the rotating plate  20  to rotate the seat, and generate braking force against rotational force coming from the seat when the motor  40  is stopped and maintain the stopped state, thereby fixing the seat in a non-rotatable state. A detailed configuration of the brake unit  30  will be described again below. 
     The motor  40  is fixedly installed below the fixed plate  10  through the mounting plate  50 . The mounting plate  50  is a metal plate installed at a predetermined gap to a bottom of the fixed plate  10 , and it is preferable to weld the mounting plate  50  to the fixed plate  10 . 
     The motor  40  is a geared motor that is integrally equipped with a gear box  41  for deceleration, and a mounting bracket  42  is provided on the gear box  41 . An output gear  43  of the gear box  41  protrudes upward through a central portion of the mounting bracket  42 . 
     In a center of the mounting plate  50 , a through hole  51  of which a center coincides with centers of the through hole  11  of the fixed plate  10  and the through hole  21  of the rotating plate  20  is formed, and a gear hole  52  into which the output gear  43  is inserted is formed on an outer side of the through hole  51 . 
     The mounting bracket  42  is bolted to an underside of the mounting plate  50  so that the output gear  43  is inserted into the gear hole  52 . In an assembled state, the output gear  43  of motor  40  is engaged with the driving gear of brake unit  30 . 
     The brake unit  30 , which is a main component of the present disclosure, will be described with reference to  FIGS.  4  to  6   .  FIG.  4    is a top perspective view of the brake unit;  FIG.  5    is a bottom perspective view of the brake unit and  FIG.  6    is an exploded view of the brake unit. 
     The brake unit  30  is formed to have a structure where a brake plate  33 , a driving plate  34 , a side plate  36 , a wedge roller  33   d  and the like are installed between a drum housing  31  and a housing cover  32 , and the driving gear  35  is mounted to the driving plate  34  on an outside of the housing cover  32 . 
     The drum housing  31  and the housing cover  32  are welded to each other and form a space therebetween to accommodate the components. A plurality of bolt tightening portions  31   a  and  32   a  which are abutted to each other are formed at the same position on respective outer circumferential surfaces of the drum housing  31  and the housing cover  32 , and bolt holes are formed in the bolt tightening portions  31   a  and  32   a . The bolt tightening portions  31   a  and  32   a  are bolted to the mounting part  12  of the fixed plate  10 . 
     As shown in  FIGS.  6  and  7   , the brake plate  33  has wedge bosses  33   a  formed on its outer circumferential surface at equal intervals in a circumferential direction. On both sides of the wedge boss  33   a , wedge grooves  33   b  having a narrower width toward an inside are formed. With respect to the wedge boss  33   a , bottom surfaces of both wedge grooves  33   b  are wedge surfaces  33   c , and the wedge surfaces  33   c  gets lowered toward the wedge boss  33   a  (a distance from an inner circumferential surface of the drum housing  31  increases), and the wedge surfaces  33   c  gets higher as a distance from the wedge boss  33   a  increases (a distance from the inner circumferential surface of drum housing  31  decreases). 
     Wedge rollers  33   d  are provided on both sides of the wedge boss  33   a , respectively, and the wedge rollers  33   d  are elastically supported by elastic members  33   e  inserted inward of the wedge grooves  33   b . The elastic member  33   e  pushes the wedge roller  33   d  toward an upper portion of the wedge surface  33   c  to sandwich the wedge roller  33   d  between an inner circumferential surface of the drum housing  31  and the wedge surface  33   c.    
     The driving plate  34  and the side plate  36  are provided on both sides of the brake plate  33  to prevent the wedge roller  33   d  and the elastic member  33   e  from disengaging in an axial direction of the brake plate  33 . 
     A plurality of bolts  33   f  are installed on one side of the brake plate  33  in a circumferential direction, and portions where the bolts  33   f  are installed protrude in a direction of one side of the brake unit  30  through the through hole of the drum housing  31 . The bolts  33   f  are tightened to the mounting part  22  of the rotating plate  20 . Since the rotating plate  20  is fixed to the underside of the seat, the brake plate  33  rotates integrally with the seat. 
     The driving plate  34  has operating pieces  34   a  protruding toward the brake plate  33  on an outer circumferential surface thereof. The operating pieces  34   a  are formed in the same number as the wedge boss  33   a  of the brake plate  33  and are positioned between the wedge bosses  33   a.    
     Meanwhile, a portion between the wedge surfaces  33   c  of the brake plate  33  between adjacent wedge bosses  33   a  is formed as a circumferential surface (circumferential surface portion  33   g ). In addition, the operating piece  34   a  is also formed in an arc shape having the same curvature as that of the circumferential surface portion  33   g  and is in contact with (or slightly spaced from) the circumferential surface portion  33   g . In this state, when the driving plate  34  is rotated, the operating piece  34   a  slides along the circumferential surface portion  33   g  and is rotatably moved. 
     Since an end of the wedge boss  33   a  of the driving plate  34  is in contact with an inner circumferential surface of the drum housing  31 , as described above, the operating piece  34   a  of the driving plate  34  is in contact with the circumferential surface portion  33   g  of the brake plate  33 , so that centers of rotation of the drum housing  31 , the brake plate  33 , and the driving plate  34  coincide, thereby helping accurately maintain coaxial relationship between parts. 
     Meanwhile, a plurality of coupling pieces  34   b  are formed to protrude toward the housing cover  32  on an inner circumferential surface of the driving plate  34 . The coupling pieces  34   b  are inserted into and seat on an inner diameter surface of the driving gear  35  located outside the housing cover  32  and are welded to the inner diameter surface. Therefore, the driving gear  35  and the driving plate  34  are rotated integrally. 
     The assembled state of the brake unit  30  assembled in the above-described structure can be seen in  FIGS.  4  and  5   . 
     For the brake unit  30 , the bolt tightening portions  31   a  and  32   a  are bolted to the mounting part  12  of the fixed plate  10 . In the mounted state, the driving gear  35  of the brake unit  30  protrudes downward from the fixed plate  10  through the inner diameter section of the fixed plate  10 , and the output gear  43  of the motor  40  is engaged with the driving gear  35 . 
     Now, the advantageous effect of the present disclosure will be described. 
     A seat is fixed to a seat rail of a vehicle floor through the power swivel device according to the present disclosure. In a normal use state (motor  40  is in an off-state), a state of the brake unit  30  is that the wedge roller  33   d  is pushed up to a high side of the wedge surface  33   c  by the elastic member  33   e , as shown in  FIG.  7 ( a ) . 
     In the above state, when an external force is applied to the seat in a rotational direction, rotational force is delivered to the brake plate  33  connected to the seat, and rotation of the brake plate  33  becomes impossible because the wedge roller  33   d  opposite to a rotational direction with respect to the wedge boss  33   a  is caught between an inner circumferential surface of the drum housing  31  and the wedge surface  33   c  of the brake plate  33 . Since wedge rollers  33   d  are provided on both sides of the wedge boss  33   a , the brake plate  33  cannot rotate in both directions. As such, the rotation of the brake plate  33  is constrained by the wedge roller  33   d  being caught, so there is no clearance in a rotational direction between the drum housing  31  and the brake plate  33  and accordingly, no flow in the rotational direction occurs in the seat. Therefore, stability of the seat fixation in a rotational direction is greatly improved. 
     Meanwhile, when the user manipulates operation button (switch) of the power swivel device to supply power to the motor  40  and the motor  40  is rotated in one direction, the output gear  43  of the motor  40  is rotated, the driving gear  35  engaged with the output gear  43  is rotated, and the driving plate  34  is rotated integrally with the driving gear  35 . 
     When the driving plate  34  is rotated, as shown in  FIG.  7 ( b ) , the operating piece  34   a  of the driving plate  34  moves in a rotational direction to push the wedge roller  33   d  in front in the rotational direction. Accordingly, as the wedge roller  33   d  moves downward of the wedge surface  33   c , the constraint state of the brake plate  33  with respect to the drum housing  31  is released. 
     The wedge roller  33   d  pushed downward of the wedge surface  33   c  comes into contact with an upper side of the wedge boss  33   a  and a middle portion of the wedge surface  33   c.    
     Accordingly, the rotational force of the driving plate  34  is delivered to the brake plate  33  through the operating piece  34   a , the wedge roller  33   d , and the wedge boss  33   a , thereby rotating the brake plate  33 . 
     When the wedge roller  33   d  on one side of the wedge boss  33   a  is pushed by the operating piece  34   a , the wedge roller  33   d  on an opposite side of the wedge boss  33   a  moves to a lower part of the corresponding wedge surface  33   c  by the rotation of the brake plate  33 . That is, the wedge roller  33   d  on an opposite side of the wedge boss  33   a  also cannot constrain the rotation of the brake plate  33  with respect to the drum housing  31 . 
     Therefore, when the driving plate  34  is rotated by the operation of the motor  40 , the brake plate  33  is rotated in the direction of the rotation, and the seat connected to the brake plate  33  is rotated, thereby adjustment of the direction of the seat is made available. 
     As described above, in the power swivel device according to the present disclosure, the brake unit  30  that firmly maintains a fixed state in a rotational direction without a flow is installed between the fixed plate  10  and the rotating plate  20 , thereby no flow in the rotational direction between the fixed plate  10  and the rotating plate  20  occurs. 
     Therefore, the flow in the rotational direction does not occur in the seat, so stability of the seat fixation in the rotational direction is improved, and noise due to the flow of the seat in the rotational direction is not generated while driving. 
     As described above, the stability of the seat fixation is improved and noise is not generated, thereby improving the emotional quality of the seat. 
     While the present disclosure has been particularly shown and described with reference to embodiments thereof, these embodiments are provided so that this disclosure will fully convey the concept of the present disclosure, and not for purposes of limitation. Thus, it will be obvious to one of ordinary skill in the art that various changes and other equivalents may be made therein. Therefore, the protective scope of the present disclosure is defined by the appended claims below. 
     
       
         
           
               
             
               
                   
               
               
                 [REFERENCE NUMERALS] 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                   
                 10: fixed plate 
                 20: rotating plate 
               
               
                   
                 30: brake unit 
                 31: drum housing 
               
               
                   
                 32: housing cover 
                 33: brake plate 
               
               
                   
                 34: driving plate 
                 35: driving gear 
               
               
                   
                 36: side plate 
                 40: motor 
               
               
                   
                 43: output gear 
                 50: mounting plate