Patent Publication Number: US-2020290486-A1

Title: Recliner shaft for vehicle seat

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application claims the benefit of U.S. Provisional Patent Application No. 62/817,154 filed on Mar. 12, 2019, the entire disclosures of which are incorporated herein by reference for all purposes. 
    
    
     BACKGROUND 
     1. Technical Field 
     Exemplary embodiments of the inventive concept relate to a recliner shaft. More particularly, exemplary embodiments of the inventive concept relate to a recliner shaft for a vehicle seat capable of rotating and fixing a seat back thereof with desired angel. 
     2. Description of the Related Art 
     For a vehicle seat on which a driver or passenger of a vehicle seats, a recliner is installed to adjust an angle of a seat back and a seat cushion back and forth, so that the driver or passenger of the vehicle can be kept in a suitable position for driving or can be adjusted to any desired angle. 
     Two recliners are installed at both ends of hinge-combining-portion of a cushion frame on which the seat cushion is installed and a seatback frame on which the seat back is installed, and the recliners at the both ends are connected to each other by a recliner shaft. 
     The driver or passenger can adjust the angle of the seat back by operating the recliner manually or automatically by rotating the recliner shaft. When the recliner shaft rotates, the seat back rotates forward or backward with respect to the seat cushion. 
     However, traditional recliner shaft is formed by a round bar in which is fully closed, so that there is a problem with heavy weight, accordingly, this is one factor that cannot meet a trend of lightening of a vehicle and increases a manufacturing cost as a whole. 
     SUMMARY 
     One or more exemplary embodiment of the inventive concept provides a recliner shaft with a hollow pipe form. 
     One or more exemplary embodiments of the inventive concept also provide a recliner shaft capable of maintaining a sufficient torsional strength while reducing a weight and manufacturing cost by forming a hollow therein. 
     According to an exemplary embodiment of the inventive concept, a recliner shaft includes first parts which are spaced apart from each other and form portions of a cylindrical shape, and second parts connecting the first parts and formed so as to form protrusions by protruding outward from the cylindrical shape. The second parts include a first spline protrusion and a second spline protrusion which have the same shape, and are disposed to be symmetrical with respect to a virtual straight line passing through a center of the cylindrical shape. 
     In an exemplary embodiment, the second parts may further include a third spline protrusion and a fourth spline protrusion which are disposed on the virtual straight line. 
     In an exemplary embodiment, the third spline protrusion and the fourth spline protrusion may have the same shape. 
     In an exemplary embodiment, the third spline protrusion and the first spline protrusion may have the same shape. 
     In an exemplary embodiment, the third spline protrusion and the fourth spline protrusion may be spaced apart each other and disposed at a predetermined angle along a circumferential direction of the cylindrical shape. The fourth spline protrusion and the first spline protrusion may be spaced apart each other and disposed at an angle which is greater than the predetermined angle along the circumferential direction of the cylindrical shape. 
     In an exemplary embodiment, a length of an outer circumferential surface of the fourth spline protrusion may be greater than a length of an outer circumferential surface of the third spline protrusion. 
     In an exemplary embodiment, the fourth spline protrusion may include a first curved surface portion in contact with a virtual circle having a center as the center of the cylindrical shape, and a second curved surface portion having a center of curvature at a point outside the cylindrical shape and curved at a predetermined curvature. 
     According to the recliner shaft for a vehicle seat according to the present invention, a hollow pipe hollow recliner shaft is provided, thereby contributing to weight saving of the vehicle and reducing manufacturing cost. 
     In addition, the recliner may have a hollow pipe shape, and sufficient torsional strength is maintained with light weight to transmit rotational force to a recliner device. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other features of the inventive concept will become more apparent by describing in detail exemplary embodiments thereof with reference to the accompanying drawings, in which: 
         FIG. 1  is a perspective view illustrating a recliner shaft according to an exemplary embodiment of the inventive concept; 
         FIG. 2  is a cross-sectional illustrating a recliner shaft according to an exemplary embodiment of the inventive concept; 
         FIG. 3  is a perspective view illustrating a recliner shaft according to another exemplary embodiment of the inventive concept; 
         FIG. 4  is a cross-sectional illustrating a recliner shaft according to another exemplary embodiment of the inventive concept; 
         FIG. 5  is a perspective view illustrating a recliner shaft according to still another exemplary embodiment of the inventive concept; 
         FIG. 6  is a cross-sectional illustrating a recliner shaft according to still another exemplary embodiment of the inventive concept; 
         FIG. 7  is a conceptual view illustrating an enlarged view of the fourth spline protrusion of  FIG. 6 ; and 
         FIG. 8  is a use state view of a recliner shaft according to an exemplary embodiment of the inventive concept. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, the inventive concept will be explained in detail with reference to the accompanying drawings. 
       FIG. 1  is a perspective view illustrating a recliner shaft according to an exemplary embodiment of the inventive concept. 
     Referring to  FIG. 1 , a recliner shaft  100  has a cylindrical shape including a plurality of protrusions protruding toward outside. More specifically, the recliner shaft  100  includes first parts I forming portions of the cylindrical shape, and second parts II connecting the first parts I. 
     The first parts I are spaced apart from each other so that the recliner shaft  100  has the cylindrical shape formed so as to be cut off in the middle. The second parts II are disposed between the first parts I to connect the first parts I. In addition, the second parts II are formed so as to form spline protrusions  300  by protruding outward from the cylindrical shape formed by the first parts I. 
     The second part II may transmit a rotational force by being caught in a spline groove of the recliner device  20 . In other words, the second parts II are formed so as to be engaged with the spline grooves (not shown) formed in the recliner device  20  by taking the shape of the spline protrusions  300  protruding out of the cylindrical shape. The second parts II engaged in the spline grooves when the recliner shaft  100  rotates may transmit torque to the recliner device  20  (refers to  FIG. 8 ). 
     Referring to  FIG. 1 , the plurality of spline protrusions  300  are spaced apart from each other along a circumferential direction of a body  200  to form four spline protrusions  300 . 
     The recliner shaft  100  has a shape in which a cross section of a specific shape is elongated in one direction. According to the figures, the second parts II and the first parts I extend in a straight line in a longitudinal direction of the recliner shaft  100 . In the figures, both ends of the recliner shaft  100  are shown to have the same shape, but according to another embodiment, both ends may be formed to have different shapes. 
     A hollow is formed inside the recliner shaft  100 . In other words, the recliner shaft  100  has a pipe shape with a hole in the center. 
     The hollow of the recliner shaft  100  may have a specific shape. For example, in the center of the hollow, a virtual circle having a certain radius may be drawn with respect to a center M 1  of the body  200 , and a hollow protrusion in which a portion of a circumference of the virtual circle ‘a’ protrudes to the outside can be formed. 
     The hollow protrusion may have a virtual rectangular shape having a curvature at an edge as shown in the figures. In addition, according to another embodiment of the present invention, the hollow protrusions may be formed to have a virtual circular, semicircular or elliptic shape. 
       FIG. 2  is a cross-sectional illustrating a recliner shaft according to an exemplary embodiment of the inventive concept. 
     Referring to  FIG. 2 , the recliner shaft  100  includes a plurality of spline protrusions  300 . The spline protrusions  300  are disposed to be spaced apart from each other along the circumferential direction of the body  200 . As shown in the figures, each spline protrusion  300  is spaced apart by 90 [deg.] 
     Hereinafter, for convenience of explanation, the spline protrusion in a left side in the figure is referred to as a first spline protrusion  301 , and the spline protrusion in a right side in the figure is referred to as a second spline protrusion  302 . 
     The spline protrusion in a lower side in the figure is referred to as a third spline protrusion  303 , and the spline protrusion in an upper side in the figure is referred to as a fourth spline protrusion  304 . 
     As described in the figure, the first spline protrusion  301  and the second spline protrusion  302  are formed to be symmetrical with respect to the center M 1  of the body and the third spline protrusion  303 . The fourth spline protrusion  302  and the spline protrusions  304  are formed to be symmetrical to each other. 
     Here, the first spline protrusion  301  and the second spline protrusion  302 , the second spline protrusion  302  and the third spline protrusion  303 , the third spline protrusion  303  and the fourth spline protrusion  304 , the spline protrusion  304  and the first spline protrusion  301  are spaced apart from each other at the same  90  degree intervals with respect to the center M 1  of the body  200 . As described in the figure, the first spline protrusion  301  and the second spline protrusion  302  have the same shape, and the third spline protrusion  303  and the fourth spline protrusion  304  have the same shape, but according to another embodiment, the spline protrusions may have the same shape or all the spline protrusions may have different shapes. 
     The recliner shaft  100  may be divided into first parts I constituting portions of a cylindrical shape and second parts II connecting the first parts I for convenience of explanation. 
     For example, a portion forming the body  200  of the recliner shaft  100  may be referred to as the first part I, and a portion where the spline protrusion  300  is formed may be referred to as the second part II. 
     An inner circumferential surface connecting portion and an outer circumferential surface connecting portion are formed between the spline protrusion  300  and the body  200 . 
     The inner circumferential surface connection portion connects an inner circumferential surface  310  of the spline protrusion  300  and an inner circumferential surface  210  of the body  200 . The outer circumferential surface connecting portion connects an outer circumferential surface  320  of the spline protrusion  300  and an outer circumferential surface  220  of the body  200 . 
     As shown, a curved surface portion  222  is formed at an end of the outer circumferential surface  320  of the spline protrusion  300 . The curved surface portion  222  curves with a predetermined curvature with respect to a curvature center M 2 . An extended portion  224  extending toward the outer circumferential surface  220  of the body  200  is formed at one end of the curved surface portion  222 . The curved surface portion  222  is formed so as to occupy a thickness of ‘r’ at the spline protrusion  300 . 
     The spline protrusions  300  may be formed to have a constant inclination. For example, as shown in the figure, both sides of the spline protrusion  302  may be inclined so as to have an angle of θ1 with respect to each other. 
     As a specific example of the present invention, when a diameter of the outer circumferential surface  220  of the body  200  is 7.6, a diameter of the outer circumferential surface  320  of the spline protrusion  300  is 10.6. At this time, a width of the fourth spline protrusion  304  is 5.1 and a radius of the first curved portion is 0.5. The thickness ‘r’ is 0.05 times the diameter of the outer peripheral surface  320  of the spline projection  300 . The θ1 is 26 degrees. 
       FIG. 3  is a perspective view illustrating a recliner shaft according to another exemplary embodiment of the inventive concept. 
     Referring to  FIG. 3 , a plurality of spline protrusions  300  are spaced apart from each other along a circumferential direction of a body  200  to form four spline protrusions  300 . At this time, at least one of the four spline protrusions  300  may have a different shape. For example, as shown in the figure, an upper protrusion may be formed larger than the other protrusions, or a lower protrusion may be formed smaller than the other protrusions. 
     The recliner shaft according to the present embodiment has a shape in which a cross section of a specific shape is elongated in one direction like the recliner shaft shown in  FIG. 1 . As shown, second parts II and first parts I extend in a straight line in a longitudinal direction of the recliner shaft  100 . In the figures, both ends of the recliner shaft  100  are shown to have the same shape, but according to another embodiment, both ends may be formed to have different shapes. 
     A hollow is formed inside the recliner shaft  100 . In other words, the recliner shaft  100  has a pipe shape with a hole in the center. 
     The hollow of the recliner shaft  100  may have a specific shape. For example, in the center of the hollow, a virtual circle having a certain radius may be drawn with respect to a center M 1  of the body  200 , and a hollow protrusion in which a portion of a circumference of the virtual circle ‘a’ protrudes to the outside can be formed. 
     The hollow protrusion may have a virtual rectangular shape having a curvature at an edge as shown in the figures. In addition, according to another embodiment of the present invention, the hollow protrusions may be formed to have a virtual circular, semicircular or elliptic shape. 
       FIG. 4  is a cross-sectional illustrating a recliner shaft according to another exemplary embodiment of the inventive concept. 
     According to the present embodiment, at least one of four spline protrusions may have a different shape. That is, as illustrated, the fourth spline protrusion  304  may be formed to be larger than the first, second and third spline protrusions. A length of an outer circumferential surface of the fourth spline protrusion  304  is formed to be larger than length of outer circumferential surfaces of the other spline protrusions. 
     Referring to  FIG. 4 , angle θ2 between the first spline protrusion  301  and the third spline protrusion  303  is smaller than 90 [deg.] and angle between the first spline protrusion  301  and the fourth spline protrusion  304  is smaller than 90 [deg.] In other words, the first spline protrusion  301  and the second spline protrusion  302  are slightly moved toward the third spline protrusion  303  while the fourth spline protrusion  304  is formed larger than the other protrusions. 
     In this case, the first spline protrusion  301  and the second spline protrusion  302  are disposed to be symmetrical with respect to a virtual straight line passing through a center M 1  of the cylinder shape. The third spline protrusion  303  and the fourth spline protrusion  304  are disposed on the virtual straight line. That is, a cross section of the recliner shaft is symmetrical to left and right in the figure. 
       FIG. 5  is a perspective view illustrating a recliner shaft according to still another exemplary embodiment of the inventive concept. 
     Referring to  FIG. 5 , a plurality of spline protrusions  300  are spaced apart from each other along a circumferential direction of a body  200  to form four spline protrusions  300 . At this time, at least one of the four spline protrusions  300  may have a different shape. For example, an upper protrusion may be formed larger than the other protrusions, or a lower protrusion may be formed smaller than the other protrusions. Here, as shown, one of the spline protrusions may be formed with a recessed groove toward inside of the body.  FIG. 6  is a cross-sectional illustrating a recliner shaft according to still another exemplary embodiment of the inventive concept.  FIG. 7  is a conceptual view illustrating an enlarged view of the fourth spline protrusion of  FIG. 6 . 
       FIG. 6  shows an embodiment in which a shape of the fourth spline protrusion  304  is modified in the embodiment shown in  FIG. 4 . 
     Referring to  FIGS. 6 and 7 , the fourth spline protrusion  304  has the recessed groove which is recessed toward the center of the cylindrical shape. More specifically, an outer circumferential surface  320  of the fourth spline protrusion  304  includes a first curved surface portion  225  in contact with a virtual circle having a center as the center M 1  of the cylindrical shape, and a second curved surface portion  226  having a center of curvature at a point outside the cylindrical shape and curved at a predetermined curvature. 
     A first extending portion  228  and a third curved portion  229  may be formed between the first curved surface portion  225  and the second curved surface portion  226 . The first extending portion  228  is a plane connecting the second curved surface portion  226  and the third curved surface portion  229 . The third curved surface portion  229  is formed to have a predetermined curvature with a point M 4  as a center of curvature. Depth  22  of the recessed groove may be formed such that a distance between the outer circumferential surface  320  and the inner circumferential surface  310  of the spline protrusion is equal to a thickness of the cylindrical shape. 
     As a specific example of the present invention, when a diameter of the outer circumferential surface  320  of the fourth spline protrusion  320  is 10.6, the depth of the recessed groove is 0.8, the radius of the second curved surface  226  is 1, and the radius of the third curved surface  229  is 0.5. In this case, the angle θ3 of the recessed groove is 120 [deg.] 
       FIG. 8  is a use state view of a recliner shaft according to an exemplary embodiment of the inventive concept. 
     A spline protrusion  300  protruded from an outer circumferential surface of a recliner shaft  100  is engaged with a spline groove (not shown) of a recliner device  20  to transmit a rotational force of the recliner shaft  100  to the recliner device  20 . At this time, since the spline protrusion  300  and a groove portion  400  are formed as described above, the recliner shaft  100  is formed in a hollow shape capable of reducing weight and material cost compared to conventional ones, and has enough strength capable of preventing a twist deformation. 
     The foregoing is illustrative of the inventive concept and is not to be construed as limiting thereof. Although a few exemplary embodiments of the inventive concept have been described, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of the inventive concept. Accordingly, all such modifications are intended to be included within the scope of the inventive concept as defined in the claims. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents but also equivalent structures. Therefore, it is to be understood that the foregoing is illustrative of the inventive concept and is not to be construed as limited to the specific exemplary embodiments disclosed, and that modifications to the disclosed exemplary embodiments, as well as other exemplary embodiments, are intended to be included within the scope of the appended claims. The inventive concept is defined by the following claims, with equivalents of the claims to be included therein.