Patent Publication Number: US-2015072824-A1

Title: Deceleration device for a directly electromechanically actuated planetary gear assembly in a seat adjustment mechanism and method for operating a deceleration device

Description:
The invention relates to a deceleration device for a directly electromechanically actuated planetary gear assembly in a seat adjustment mechanism and a method for operating such a deceleration device. 
     In the prior art, planetary gears, in particular wobble mechanisms, of a seat adjustment mechanism are actuated manually or driven by means of a conventional electric motor and a self-locking gear unit. 
     It is the object of the present invention to specify a deceleration device which is improved relative to the prior art for a directly electromechanically actuated planetary gear assembly in a seat adjustment mechanism and a method which is improved relative to the prior art for operating such a deceleration device. 
     With regard to the deceleration device for a directly electromechanically actuated planetary gear assembly in a seat adjustment mechanism, the object is achieved by the features set forth in claim  1 . 
     With regard to the method for operating such a deceleration device, the object is achieved by the features set forth in claim  10 . 
     Advantageous developments of the invention form the subject matter of the sub-claims. 
     According to the invention, the deceleration device for a directly electromechanically actuated planetary gear assembly in a seat adjustment mechanism is integrated into a structural unit formed from the planetary gear assembly and the electromechanical actuation thereof. In this case, such an integration is understood as an arrangement of the deceleration device between the components of the planetary gear assembly and/or the electromechanical actuation thereof. In particular, the deceleration device is arranged inside a housing surrounding the planetary gear assembly and the electromechanical actuation thereof. As a result, a particularly compact structural unit consisting of the deceleration device, the planetary gear assembly and the electromechanical actuation thereof is formed. 
     Such a deceleration device permits a more efficient adjustment of a seat adjustment mechanism than a self-locking worm gear which has a significantly lower efficiency. 
     Particularly advantageously, by means of the deceleration device a use is possible of the directly electromechanically actuated open planetary gear assembly for a vertical and longitudinal adjustment and/or a backrest adjustment of a vehicle seat. 
     In a first variant which has particularly minimal costs, the deceleration device is configured as a permanently acting friction brake which introduces a predeterminable deceleration force as a frictional force into the planetary gear assembly. A self-locking of the planetary gear assembly is achieved by means of such a permanent frictional force below a locking limit. 
     In a preferred variant, the deceleration device is configured as a wedge brake which comprises at least one bearing ring, wedge elements, a retaining spring and the corresponding actuating means. In this manner, a deceleration device is possible, the deceleration force thereof being able to be controlled. 
     Expediently, an actuator for controlling the deceleration device is driven mechanically, electrically or electromechanically. 
     Preferably, the actuator of the deceleration device is arranged on the front face on the electromechanically actuated planetary gear assembly and acts through a hollow portion of an eccentric shaft or a through-hole of the shaped portion of the fitting part on the components of the deceleration device. As a result, easy accessibility and simple contact of the actuator is achieved. 
     In an advantageous embodiment, the planetary gear assembly is configured as a single open planetary gear. In this case, such an open planetary gear is a single planetary gear with only one central wheel and a connecting shaft of a planetary gear which does not circulate coaxially. In one possible embodiment, the central wheel is formed, for example, from the outer, internally toothed fitting part and the planet wheel from the inner, externally toothed fitting part of a conventional seat adjustment mechanism. 
     In a preferred embodiment, the planetary gear assembly is configured as a combination of two open planetary gears. As a result, particularly high torques may be produced at relatively low rotational speeds. A drive unit formed from a planetary gear assembly with a plurality of planetary gears is particularly compact and cost-effective. 
     In a particularly advantageous embodiment, the deceleration device is arranged between the two coupled open planetary gears and/or in the axial direction on the fitting part. In this manner, the deceleration device may be integrated particularly easily into the planetary gear assembly and advantageously apply a frictional force onto at least one component of the planetary gear assembly, resulting in a decelerating action. 
     In a particularly advantageous embodiment, the actuator of the deceleration device is arranged between the two coupled open planetary gears, so that a particularly compact unit is thus formed from the electromechanically actuated combination of two open planetary gears and the deceleration device. 
     In this manner, a deceleration device for an electromechanically actuated planetary gear assembly which is optimized, compact and cost-effective is possible. 
     In the method for operating a deceleration device for a directly electromechanically actuated planetary gear assembly in a seat adjustment mechanism, the deceleration device is controlled or regulated such that a decelerating action is effected during the stoppage of the electromechanically actuated planetary gear assembly and is cancelled directly before or at the start of an adjusting movement of the electromechanically actuated planetary gear assembly. 
     As a result, in a non-actuated state the deceleration device decelerates the planetary gear assembly and holds said assembly in a fixed position. 
     Thus such a planetary gear assembly with a deceleration device may be used for a vertical and longitudinal adjustment and/or a backrest adjustment of a vehicle seat, as in this application a decelerating action is required in order to avoid an inadvertent adjustment of the components of the vehicle seat. In particular, in the event of a crash, self-locking is particularly advantageous as this counteracts an adjustment of the vehicle seat due to the forces resulting from an accident which act thereon. 
    
    
     
       The invention is described in more detail with reference to the accompanying schematic figures, in which: 
         FIG. 1  shows schematically an exploded view of a planetary gear assembly as an electromechanically actuated planetary gear, 
         FIG. 2  shows schematically an exploded view of an electromechanically actuated planetary gear assembly as a combination of two open planetary gears, 
         FIG. 3  shows schematically a deceleration device according to the invention, 
         FIG. 4  shows schematically a sectional view of an electromechanically actuated planetary gear assembly as a combination of two open planetary gears with a rotationally actuated deceleration device, 
         FIG. 5  shows schematically a rotationally actuated deceleration device which is controlled depending on the direction of movement, 
         FIG. 6  shows schematically a rotationally actuated deceleration device which is controlled irrespective of the direction of movement and 
         FIG. 7  shows schematically a sectional view of an electromechanically actuated planetary gear assembly as a combination of two open planetary gears with a deceleration device actuated in a linear manner. 
     
    
    
     Parts which correspond to one another are provided in all of the figures with the same reference numerals. 
       FIG. 1  shows schematically an exploded view of an electromechanically actuated planetary gear assembly P as an electromechanically actuated open planetary gear  1 . 
     Such an open planetary gear  1  comprises at least one inner, externally toothed fitting part  2 , an outer, internally toothed fitting part  3 , a magnetic ring  4 , a housing  5  and an eccentric shaft  6 . 
     In a mounted state of the electromechanically actuated open planetary gear  1 , which is ready for operation, the inner, externally toothed fitting part  2  is arranged at least partially or in regions in the outer, internally toothed fitting part  3  such that an external toothing  7  of the fitting part  2  is able to roll on an internal toothing  8  of the fitting part  3  in the conventional manner. In this case, the external toothing  7  and the internal toothing  8 , with the same module, have a number of teeth which differs by at least one tooth, wherein the number of teeth of the internal toothing  8  is greater than the number of teeth of the external toothing  7 . 
     The fitting parts  3  and  2  are preferably shaped by a non-cutting shaping process, for example as a sheet metal stamped part, sheet metal punched part, die cast part, from a metal material or a fiber reinforced plastics or a plastics mixture. 
     During operation of the electromechanically actuated open planetary gear  1 , the fitting part  2 , in a manner not shown, is rotatably arranged on the fitting part  3  and, for example, held by means of the housing  5 . 
     The eccentric shaft  6  is configured in the form of a shaft on which preferably an eccentric portion  9  is centrally arranged. The eccentric shaft  6  is rotatably arranged with a first shaft portion in a bearing of the fitting part  3  and with its eccentric portion  9  is rotatably arranged in a central recess  10  of the fitting part  2 . 
     The recess  10  and the eccentric portion  9  are shaped such that the constructional space for the components of the deceleration device  22  is produced between the recess  10  and the eccentric portion  9 . The magnetic ring  4  is preferably formed from a plurality of magnetic coils arranged in an annular manner. In this case, an internal periphery  11  of the magnetic ring  4  is formed so as to correspond to the fitting part  2  and the wobble movement thereof along the internal toothing  8  of the fitting part  3 , wherein ‘wobble movement’ is denoted as a movement about a rotational axis which alters in the spatial position thereof. 
     The magnetic ring  4  is preferably arranged fixed to a framework on the front face on the fitting part  3 . 
     At least one multi-core electrical connecting cable  12  is arranged on the magnetic ring  4 . 
     During operation of the electromechanically actuated open planetary gear  1  the individual magnetic coils of the magnetic ring  4  are activated one after the other so as to overlap in the peripheral direction of the magnetic ring  4 , so that the respective magnetic field thereof acts on the inner, externally toothed fitting part  2 , and sets said fitting part into a rotational wobble movement. This wobble movement is transmitted to the eccentric portion  9  of the eccentric shaft  6  and effects a rotation of the eccentric shaft  6 . 
     By means of the deceleration device  22 , the planetary gear  1  may be stopped and secured against inadvertent movement. 
       FIG. 2  shows schematically an alternative exemplary embodiment for a planetary gear assembly P in an exploded view as a combination of two open planetary gears  1 ,  13  which form a geared motor. 
     In the planetary gear assembly P, as a combination of two open planetary gears  1 ,  13  to form a geared motor, both open planetary gears  1 ,  13  are mechanically coupled together. In this case, the second open planetary gear  13  comprises a second inner, externally toothed fitting part  14  and a second outer, internally toothed fitting part  15  which are operatively connected together as already described with reference to the planetary gear  1 , and roll against one another in the conventional manner. 
     The first inner, externally toothed fitting part  2  of the first planetary gear  1  and the second inner, externally toothed fitting part  14  of the second planetary gear  13  are, in a manner not shown, rotatably held in and/or on the fitting part  3 . To this end, the fitting parts  2  and  14  are coupled fixedly in terms of rotation or rigidly together. 
     The first inner fitting part  2  has a shaped portion  16  into which the recess  10  is incorporated as a through-hole  17 . The second inner fitting part  14  has a shaped portion  18  in which a further through-hole  19  is incorporated. In this case an outer periphery  20  of the shaped portion  18  of the fitting part  14  is shaped so as to correspond to the through-hole  17  of the fitting part  2 , so that the shaped portion  16  of the first inner, externally toothed fitting part  2  and the shaped portion  18  of the second inner, externally toothed fitting part  14  may be arranged on one another on the front face by a positive, material and/or non positive connection. As a result, during operation, the fitting parts  2  and  14  are arranged in a rotationally fixed manner relative to one another and are mechanically operatively connected together. The respective length of the shaped portions  16  and  18 , in this case, may be adjusted in a variable manner. For example, a long shaped portion  16  may be combined with a short shaped portion  18  and vice versa. 
     The first inner, externally toothed fitting part  2  is arranged in the outer, internally toothed fitting part  3  such that an external toothing  7  of the fitting part  2  is able to roll on the internal toothing  8  of the fitting part  3  in the manner already disclosed. 
     In this exemplary embodiment, the eccentric shaft  6  comprises a first eccentric portion  34  which is partially arranged inside the bearing  35  and inside the through-hole  17  and  19  of the inner, externally toothed fitting parts  2  and  14 . At the end, on the end of the eccentric portion  34  opposing the bearing  35 , in the region of the inner, externally toothed fitting part  14  on the eccentric shaft  6 , a second outer, internally toothed fitting part  15  is arranged. This second outer, internally toothed fitting part  15  is arranged fixedly in terms of rotation on the eccentric shaft  6  and, in a manner not shown in more detail, is mounted in the housing  5  with as little friction as possible, for example mounted in a sliding manner, on rolling bearings or rollers. 
     The bearing  35  may be formed integrally in the fitting part  3  or may be arranged as a separate bearing  35 , for example as a bearing bush in the fitting part  3 . 
     In a mounted state of the electromechanically actuated planetary gear assembly P, which is ready for operation, consisting of the combination of two wobble mechanisms  1  and  13 , the second inner, externally toothed fitting part  14  is arranged at least partially or in regions in the second outer, internally toothed fitting part  15  such that an external toothing  36  of the fitting part  15  may roll in the conventional manner on an internal toothing  37  of the fitting part  14 , resulting in a relative movement between the fitting parts  14  and  15 . In this case, the external toothing  36  and the internal toothing  37 , with the same module, have a number of teeth which differs by at least one tooth, wherein the number of teeth of the internal toothing  37  is greater than the number of teeth of the external toothing  36 . The fitting parts  14  and  15  are in this case preferably shaped by means of a non-cutting shaping process, for example as a sheet metal stamped part. 
     In this case, the difference in the number of teeth and/or an absolute number of teeth of the respective internal toothings  8 ,  36  and external toothings  7 ,  37  may differ between the wobble mechanisms  1  and  13  coupled together. In particular, a variation of the absolute number of teeth and/or the respective difference in the number of teeth of the wobble mechanisms  1  and  13 , in particular the teeth thereof  7 ,  8 ,  36 ,  37 , produces a different gear reduction of the planetary gear assembly P, wherein the coupled wobble mechanisms  1  and  13  have the same eccentricity. 
     During operation of the planetary gear assembly P, the fitting part  15  is held rotatably on the fitting part  14  in a manner not shown. 
     The magnetic ring  4  axially encloses or surrounds the shaped portion  18  of the second internally toothed fitting part  14  and the shaped portion  16  of the first internally toothed fitting part  2 , so that the fitting parts  2  and  14  in each case are arranged on the front face on the magnetic ring  4 . 
     During operation of the electromechanically actuated planetary gear assembly P, the individual magnetic coils of the magnetic ring  4  are activated one after the other so as to overlap in the peripheral direction of the magnetic ring  4 , so that the respective magnetic field thereof acts on the two coupled inner, externally toothed fitting parts  2  and  14  and sets said fitting parts into a rotational wobble movement. In this case, the external toothing  7  of the first inner, externally toothed fitting part  2  rolls along the internal toothing  8  of the first outer, internally toothed fitting part  3 . 
     The external toothing  36  of the second inner, externally toothed fitting part  14  rolls along the internal toothing  37  of the second outer, internally toothed fitting part  15 . As a result, the second outer, internally toothed fitting part  15  is set into a rotational movement relative to the first outer, internally toothed fitting part  3 . 
     By means of this variant, a particularly slow-running electromechanically actuated planetary gear assembly P is possible. 
     During an operation of the geared motor, which is formed from the electromechanically actuated planetary gear assembly P and thus the electromechanically actuated open planetary gears  1 ,  13  coupled together, as part of an inclination, longitudinal or vertical adjustment device, a spur gear  21  is preferably arranged on the eccentric shaft  6 . 
     A deceleration device  22  is preferably arranged in the region between the two wobble mechanisms  1 ,  13  and/or in the axial direction on the fitting part  3  and acts on the eccentric shaft  6 . 
       FIG. 3  shows schematically a deceleration device  22  according to the invention. 
     In a first variant, not shown, the deceleration device  22  is configured as a permanently acting friction brake which introduces a predeterminable deceleration force as a frictional force into the open planetary gear(s)  1 ,  13  and, for example, acts on the eccentric shaft  6 . By means of such a permanent frictional force below a locking limit, a self-locking of the open planetary gear  1 ,  13  is achieved. For applying the deceleration force a spring acts with a predeterminable spring force permanently on the wedge elements  25 . 
     In a preferred variant, the deceleration device  22  is configured as a conventional wedge brake. 
     The wedge elements  25  are forced apart in the peripheral direction by bent-back spring ends of a spring, not shown, so that any clearance in the toothing and in the bearing is avoided. To this end, the spring ends engage in recesses  26  of the wedge elements  25  by pretensioning. 
     An actuation, in particular the lifting, of the wedge elements  25  effects a relative movement of the wedge elements  25  and the actuating means  28  and thus a release of the deceleration device  22  which in a non-actuated state decelerates the planetary gear assembly P and holds said assembly in an unalterable position. 
     For actuating the wedge elements  25 , the through-hole  19  of the eccentric portion  34  of the fitting part  14  is widened by means of a groove-shaped opening  27 . A corresponding bearing portion  38  of an actuating means  28  is arranged in the through-hole  19 . A transmission portion  29  of the actuating means  28  is arranged in the opening  27  such that the actuating means  28  is partially pivotable in the peripheral direction of the eccentric portion  34 . 
     For releasing the deceleration force of the wedge elements  25 , the actuating means  28  is pivoted so that the actuating means  28  and eccentric portion  34  come to bear against one another, wherein the deceleration device  22  is released and subsequently, when rotating the planetary gear assembly P, a common further movement takes place in the rotational direction of the planetary gear assembly P. 
       FIG. 4  shows schematically a sectional view of an electromechanically actuated planetary gear assembly P as a combination of two open planetary gears  1 ,  13  with a rotationally actuated deceleration device  22 . 
     A release of the deceleration device  22  takes place by means of a conventional actuator  30  which is advantageously configured mechanically, electrically or electromechanically. 
     In a first variant, the deceleration device  22  is released rotationally by means of the actuator  30 , i.e. the actuator  30  performs a rotational movement which effects the actuation of the wedge elements  25 . 
     In a first variant, the actuator  30  of the deceleration device  22  is arranged on the front face at a first position I on the electromechanically actuated open planetary gear  1 . In this case, the first position I is configured on the front face  31  opposing the output side  32  of the electromechanically actuated planetary gear assembly P as a combination of two open planetary gears  1 ,  13 . 
     In this case, the actuator  30  acts indirectly through a hollow portion of the eccentric shaft  6  or the through-hole  19  of the shaped portion  18  of the fitting part  14  on the components of the deceleration device  22 , in particular the wedge elements  25 . 
     In an alternative variant, the actuator  30  of the deceleration device  22  of an electromechanically actuated planetary gear assembly P is arranged as a combination of two open planetary gears  1 ,  13  in the region between the two coupled planetary gears  1 ,  13  at a second position II. Thus a particularly compact unit consisting of the electromechanically actuated planetary gear assembly P as a combination of two open planetary gears  1 ,  13  and the deceleration device  22  is formed. 
       FIG. 5  shows schematically a rotationally releasing deceleration device  22  which is controlled depending on the direction of movement of the actuator  30 . In this case, a pivoting movement of the actuating means  28  effects in the direction A a release of the corresponding wedge element  25  and thus a partial release of the deceleration device  22 , as the other wedge element  25  also applies a frictional force. After the actuating means  28  and eccentric portion  34  come to bear against one another during the rotation of the planetary gear assembly P in the direction A, a combined further movement of all components takes place in the rotational direction of the planetary gear assembly P. 
     A pivoting movement of the actuating means  28  in the opposing direction B effects a release of the other wedge element  25  and a partial release of the deceleration device  22 . Accordingly, a rotational direction of the planetary gear assembly P is oriented in the direction B. 
       FIG. 6  shows schematically a rotationally releasing deceleration device  22  which is controlled irrespective of the direction of movement of the actuator  30 . In this variant, the actuating means  28  is configured in two parts and, in particular, has two opposing pivotable actuating portions  33 . An actuation of the actuating means  28  effects a pivoting movement of the one actuating portion  33  in the direction A toward the corresponding wedge element  25  whilst at the same time the other actuating portion  33  in the direction B pivots toward the corresponding wedge element  25 . Thus the two actuating portions  33  are spread apart. In this manner, both wedge elements  25  are activated together, irrespective of the direction of movement of the actuator  30  and the deceleration device  22  is fully released. 
       FIG. 7  shows schematically a sectional view of an electromechanically actuated planetary gear assembly P as a combination of two open planetary gears  1 ,  13  with a deceleration device  22  actuated in a linear manner. 
     In this variant, the deceleration device  22  is released in a linear manner by means of the actuator  30 , i.e. the actuator  30  performs a linear movement which effects the release of the wedge elements  25 . 
     In this case, the linear movement takes place in the axial direction of the eccentric shaft  6  and by corresponding means, for example an actuating rod  39 , said linear movement is converted into a pivoting movement of the actuating means  28 . Such a means for converting the action may, for example, be configured according to the wedge principle or screw thread principle. 
     In a first variant, the actuator  30  of the deceleration device  22  is arranged on the front face at the first position I on the electromechanically actuated open planetary gear  1 . 
     In this case, the actuator  30  acts through a hollow portion of the eccentric shaft  6  or the through-hole  19  of the eccentric portion  34  of the fitting part  14  indirectly on the components of the deceleration device  22 , in particular the wedge elements  25 . 
     In an alternative variant, the actuator  30  of the deceleration device  22  of an electromechanically actuated planetary gear assembly P as a combination of two open planetary gears  1 ,  13  is arranged in the region between the two coupled planetary gears  1 ,  13  at a second position II. Thus, a particularly compact unit made up of the electromechanically actuated planetary gear assembly P, as a combination of two open planetary gears  1 ,  13  and the deceleration device  22 , is formed. 
     LIST OF REFERENCE NUMERALS 
     
         
           1  Electromechanically actuated open planetary 
         gear 
           2  Inner, externally toothed fitting part 
           3  Outer, internally toothed fitting part 
           4  Magnetic ring 
           5  Housing 
           6  Eccentric shaft 
           7  External toothing 
           8  Internal toothing 
           9  Eccentric portion 
           10  Recess 
           11  Internal periphery 
           12  Connecting line 
           13  Second open planetary gear 
           14  Second inner, externally toothed fitting part 
           15  Second outer, internally toothed fitting part 
           16  Shaped portion 
           17  Through-hole 
           18  Shaped portion 
           19  Through-hole 
           20  External periphery 
           21  Spur gear 
           22  Deceleration device 
           23  Internal periphery 
           24  Bearing ring 
           25  Wedge element 
           26  Recess 
           27  Opening 
           28  Actuating means 
           29  Transmission portion 
           30  Actuator 
           31  Front face 
           32  Output side 
           33  Actuating portion 
           34  Eccentric portion 
           35  Bearing 
           36  External toothing 
           37  Internal toothing 
           38  Bearing portion 
           39  Actuating rod 
         I First position 
         II Second position 
         A, B Direction 
         P Planetary gear assembly