Patent Publication Number: US-2016221478-A1

Title: Seat recliner

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application claims benefit of priority under 35 U.S.C. §119 to Japanese Patent Application No. 2015-18253 filed in Japan on Feb. 2, 2015, which is hereby incorporated by reference. 
     BACKGROUND OF THE INVENTION 
     1. Technical Field 
     The present invention relates to a seat recliner that enables of adjusting and holding a seatback position at an inclined angle desired by a passenger. 
     2. Background Arts 
     A Patent Documents 1 (Japanese Patent Application Publication No. 2008-154992) discloses a seat recliner  101  as shown in  FIG. 7 . The seat recliner  101  includes a base member  110  that is fixed with a seat cushion (not shown in  FIG. 7 ) as a seating portion, and a rotatable member  120  that is fixed with a seatback (not shown in  FIG. 7 ) rotatably supported by the seat cushion so as to be rotatable relatively to the base member  110 . A ring-shaped protrusion  111  protruding in an axial direction of a rotary shaft  142  is formed annularly on a circumference of the base member  110 . The rotatable member  120  has an almost circular disk shape, and is disposed rotatably within the ring-shaped protrusion  111  of the base member  110 . In addition, a lock mechanism  140  is provided in an accommodation space  127  formed between the base member  110  and the rotatable member  120 . The seatback is adjusted to a desired inclined angle by rotating the rotary shaft  142  after unlocking the lock mechanism  140 , and then the seatback is held at the desired inclined angle by locking the lock mechanism  140 . 
     SUMMARY OF THE INVENTION 
     In the seat recliner disclosed in the above Patent Document 1, when the rotatable member  120  is displaced in the axial direction or displaced in a separation manner so as to be peeled off from the base member  110  according to magnitude and a direction of a load caused by a passenger&#39;s reclining onto the seatback, noises may occur due to scratching between a ridge  115  of an opening edge portion  114  of the ring-shaped protrusion  111  and an outer circumferential surface  124  of the rotatable member  120 . 
     An object of the present invention is to provide a seat recliner that can prevent noises caused by passenger&#39;s reclining onto a seatback. 
     An aspect of the present invention provides A seat recliner comprising: an outer case that has an almost circular disk shape and is provided with a ring-shaped protrusion that is formed along a circumference thereof and is protruded in a thickness direction thereof; an inner case that as an almost circular disk shape and is provided inside the ring-shaped protrusion rotatably in a circumferential direction thereof; a holder that has an almost circular ring shape and covers outer circumferential surfaces of the outer and inner cases to restrict displacement of the inner case so as to be distanced from the outer case; and an escape portion that is formed by depressing one of an opening edge portion on an inner circumferential surface of the ring-shaped protrusion and a portion, on an outer circumferential surface of the inner case, facing to the opening edge portion to be distanced from another of the opening edge portion and the portion facing to the opening edge portion. 
     According to the aspect, by providing the escape portion, the opening edge portion of the ring protrusion is prevented from contacting with the outer circumferential surface of the inner case. Therefore, even if the inner case is displaced in its thickness direction or in its radial direction or displaced in a separation manner so as to be peeled off from the outer case according to magnitude and a direction of an input load, sticking of the opening edge portion with the outer circumferential surface of the inner case never occurs and thereby noise generation can be prevented. 
     It is preferable that the escape portion is formed on the outer circumferential surface of the inner case at the portion facing to the opening edge portion. 
     In this case, a width within which an inner circumferential surface of the ring-shaped protrusion slidably contacts with the outer circumferential surface of the inner case can be made larger than that in a case where the escape portion is formed at the opening edge portion on the inner circumferential surface of the ring-shaped protrusion. Therefore, rotations of the inner case within the ring-shaped outer circumferential portion can be made stable, and stability in strength and prevention of rattling can be also achieved. 
     It is preferable that a sloped portion is formed between the outer circumferential surface of the inner case and the escape portion, and the outer circumferential surface, the sloped portion and the escape portion form a smoothly continuous surface. 
     In this case, the above-mentioned sticking of the opening edge portion with the outer circumferential surface of the inner case can be further avoided and thereby the noise generation can be further prevented. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front view of a seat recliner according to a first embodiment; 
         FIG. 2  is a cross-sectional view taken along a line II-II shown in  FIG. 1 ; 
         FIG. 3  is an enlarged cross-sectional view of a portion III shown in  FIG. 2 ; 
         FIG. 4  is an enlarged cross-sectional view according to a modified example of the first embodiment, and shows a portion corresponding to the portion III shown in  FIG. 2 ; 
         FIG. 5  is an enlarged cross-sectional view according to a second embodiment, and shows a portion corresponding to the portion III shown in  FIG. 2 ; 
         FIG. 6  is an enlarged cross-sectional view according to a third embodiment, and shows a portion corresponding to the portion III shown in  FIG. 2 ; and 
         FIG. 7  is a cross-sectional view of a prior-art seat recliner. 
     
    
    
     DESCRIPTION OF THE EMBODIMENT 
     Hereinafter, embodiments will be described with reference to the drawings. As shown in  FIGS. 1 to 3 , a seat recliner  1  according to a first embodiment includes a base member  10 A that is fixed with a seat cushion SC, a rotatable member  20 A that is fixed with a seatback SB so as to be rotatable relatively to the base member  10 A, a holder  30 A that has a circular ring shape and covers outer circumferential surfaces of the base member  10 A and the rotatable member  20 A to restrict their displacements in an axial direction of a rotary shaft  42 , and a lock mechanism  40  that controls rotations of the rotatable member  20 A relative to the base member  10 A. 
     The base member  10 A (outer case) has an almost circular disk shape. In addition, a ring-shaped outer circumferential portion  11 A (ring-shaped protrusion) that is protruded in a thickness direction is formed on a circumference of the base member  10 A, and a circular depressed portion  12  (see  FIG. 3 ) is formed inside the ring-shaped outer circumferential portion  11 A. The ring-shaped outer circumferential portion  11 A and the circular depressed portion  12  are formed by half-blanking during press-working of the base member  10 A. Further, base-side fixation protrusions  13  that are protruded to a rear-surface side of the circular depressed portion  12  (to its plate outer-surface side) are also formed by half-blanking the circular depressed portion  12  during press-working of the base member  10 A. The base member  10 A and a base plate SC 1  are integrated with each other by inserting the base-side fixation protrusions  13  into base-side fixation holes SC 2  opened on the base plate SC 1  and then welding them together. Furthermore, the base member  10 A is fixed with the seat cushion SC via the base plate SC 1 . 
     The rotatable member  20 A (inner case) has an almost circular disk shape one-size smaller than the almost circular disk shape of the base member  10 A, and disposed in the circular depressed portion  12  of the ring-shaped outer circumferential portion  11 A coaxially with the circular depressed portion  12  of the ring-shaped outer circumferential portion  11 A (with the base member  10 A) so as to be rotatable relatively to the circular depressed portion  12  of the ring-shaped outer circumferential portion  11 A (to the base member  10 A). In addition, a ring-shaped slidably-contact portion  21 A that is protruded in the thickness direction is formed on a circumference of the rotatable member  20 A, and an accommodation depressed portion  22  is formed inside the ring-shaped slidably-contact portion  21 A. The ring-shaped slidably-contact portion  21 A and the accommodation depressed portion  22  are formed by half-blanking during press-working of the rotatable member  20 A. Further, rotatable-side fixation protrusions  23  that are protruded to a rear-surface side of the accommodation depressed portion  22  (to its plate outer-surface side) are also formed by half-blanking the accommodation depressed portion  22  during press-working of the rotatable member  20 A. The rotatable member  20 A and a rotatable plate SB 1  are integrated with each other by inserting the rotatable-side fixation protrusions  23  into rotatable-side fixation holes SB 2  opened on the rotatable plate SB 1  and then welding them together. Furthermore, the rotatable member  20 A is fixed with the seatback SB via the rotatable plate SB 1 . 
     As shown in  FIG. 3 , an escape portion  25 A is formed on the outer circumferential surface  24  of the rotatable member  20 A from its portion facing to an opening edge portion  14  toward its plate outer-surface. The escape portion  25 A is formed so that its diameter r 25  from a center O of the rotatable member  20 A to the escape portion  25 A is made smaller than a diameter r 24  from the center O to the outer circumferential surface  24 . In addition, the diameter r 25  of the escape portion  25 A is made constant so that the escape portion  25 A is made parallel to the outer circumferential surface  24 . Namely, the escape portion  25 A is formed by depressing the portion, on the outer circumferential surface  24 , facing to the opening edge portion  14  to be distanced from the opening edge portion  14 . Therefore, a gap H is formed between the opening edge portion  14  and the escape portion  25 A. 
     Note that the gap H is set to 0.2 to 0.5 mm or so. A width of the escape portion  25 A in the thickness (axial) direction is set so that, even if the rotatable member  20 A (inner case) is displaced from the base member  10 A (outer case) in the above-explained separation manner, the opening edge portion  14  of the ring-shaped outer circumferential portion  11 A (ring-shaped protrusion) doesn&#39;t contact with the outer circumferential surface  24 . 
     In addition, a sloped portion  26  is formed between the outer circumferential surface  24  and the escape portion  25 A. The sloped portion  26  is formed as a tapered inclined (curved) surface with which the outer circumferential surface  24  and the escape portion  25 A forms a smoothly continuous surface. 
     The holder  30 A has an almost ring shape, and includes a main body  31  wound around the outer circumferential surface of the base member  10 A, a base-side restriction portion  32  that is expanded from one end of the main body  31  and engaged with an outer-side surface of the circumference of the base member  10 A, and a rotatable-side restriction portion  33  that is engaged with an outer-side surface of the circumference of the rotatable member  20 A. By the base-side restriction portion  32  and the rotatable-side restriction portion  33 , the rotatable member  20 A is held rotatably while being restricted from being displacing so as to be distanced from the base member  10 A. 
     The lock mechanism  40  is disposed in the accommodation space  27  formed between the circular depressed portion  12  of the base member  10 A and the accommodation depressed portion  22  of the rotatable member  20 A. The lock mechanism  40  is configured to lock or unlock rotations of the rotatable member  20 A relative to the base member  10 A by rotating the rotary shaft  42  located at the center O of the rotatable member  20 A by use of an operational lever  41 . 
     Next, production processes of the above components will be explained. With respect to the base member  10 A, the ring-shaped outer circumferential portion  11 A is formed by half-blanking a center portion of a circular disk plate during press-working for making the base member  10 A. As the result, the ring-shaped outer circumferential portion  11 A is formed along an outer circumference of the disk plate (the base member  10 A), and the circular depressed portion  12  is formed inside the ring-shaped outer circumferential portion  11 A. Subsequently (or concurrently), the base-side fixation protrusions  13  are formed by half-blanking the circular depressed portion  12  to protrude the base-side fixation protrusions  13  to the plate outer-surface side of the disk plate (to the rear-surface side of the circular depressed portion  12 ). In this manner, production of the base member  10 A is completed. 
     Note that compressive stresses apply to portions near the half-blanked portions when forming the ring-shaped outer circumferential portion  11 A and the base-side fixation protrusions  13 . Therefore, the compressive stresses may develop when the base-side fixation protrusions  13  are welded to the base plate SC 1  (the base-side fixation holes SC 2 ), and thereby the base member  10 A may get distorted. Especially, the compressive stresses may develop so as to incline the ring-shaped outer circumferential portion  11 A slightly inward (i.e. toward the circular depressed portion  12 ). 
     Also with respect to the rotatable member  20 A, the ring-shaped slidably-contact portion  21 A is formed by half-blanking a center portion of a circular disk plate during press-working for making the rotatable member  20 A. As the result, the ring-shaped slidably-contact portion  21 A is protruded along an outer circumference of the disk plate (the rotatable member  20 A), and the accommodation depressed portion  22  is formed inside the ring-shaped slidably-contact portion  21 A. Subsequently (or concurrently), the rotatable-side fixation protrusions  23  are formed by half-blanking the accommodation depressed portion  22  to protrude the rotatable-side fixation protrusions  23  to the plate outer-surface side of the disk plate (to the rear-surface side of the accommodation depressed portion  22 ). Next, the rotatable member  20 A is quenched in order to improve its strength. By quenching, the rotatable member  20 A may be distorted slightly. However, the rotatable member  20 A that remains distorted cannot rotate smoothly. Therefore, the outer circumferential surface  24  of the rotatable member  20 A is reshaped to have a precisely-circular shape by a turning process. The sloped portion  26  and the escape portion  25 A are also formed by cutting in this turning process for the outer circumferential surface  24 . In this manner, production of the rotatable member  20 A is completed. 
     Next, assembling processes of the seat recliner  1  will be explained. Components that constitute the lock mechanism  40  are set at predetermined positions within the circular depressed portion  12  of the base member  10 A, and then the rotatable member  20 A is put on the base member  10 A (and the components of the lock mechanism  40 ). Subsequently, the holder  30 A is attached, from a side of the rotatable member  20 A, to the outer circumference of the base member  10 A that is preliminarily assembled with the rotatable member  20 A and the lock mechanism  40 , and thereby the holder  30 A is swaged to form the base-side restriction portion  32 . As the result, the rotatable member  20 A is held by the base member  10 A so that the rotatable member  20 A can rotate relatively to the base member  10 A. Then, the base-side fixation protrusions  13  of the base member  10 A are welded with the base-side fixation holes SC 2  of the base plate SC 1  to integrate the base member  10 A with the base plate SC 1 . Similarly, the rotatable-side fixation protrusions  23  of the rotatable member  20 A are welded with the rotatable-side fixation holes SB 2  of the rotatable plate SB 1  to integrate the rotatable member  20 A with the rotatable plate SB 1 . In this manner, assembling of the seat recliner  1  is completed. With respect to the assembled seat recliner  1 , the base plate SC 1  is fixed with the seat cushion SC, and the rotatable plate SB 1  is fixed with the seatback SB. 
     As already explained, a seat recliner that isn&#39;t provided with the escape portion  25 A and the sloped portion  26  of the present embodiment may generate noises when a passenger reclines onto the seatback SB. Such noises are generated by the inclination of the ring-shaped outer circumferential portion  11 A caused by the development of the compressive stresses. The rotatable member  20 A is displaced in the axial direction and/or a radial direction of the rotary shaft  42  or displaced in the above-explained separation manner according to magnitude and a direction of a load caused by passenger&#39;s reclining onto the seatback SB. When the rotatable member  20 A is displaced, noises (hitting sounds) may occur due to scratching between a ridge  15  of the opening edge portion  14  of the ring-shaped outer circumferential portion  11 A and the outer circumferential surface  24  of the rotatable member  20 A. 
     However, according to the seat recliner  1  in the present embodiment, the opening edge portion  14  of the ring-shaped outer circumferential portion  11 A is prevented from contacting with the outer circumferential surface  24  of the rotatable member  20 A by providing the escape portion  25 A and the sloped portion  26 , even if the load that causes the displacement of the rotatable member  20 A in the axial direction and/or the radial direction of the rotary shaft  42  or in the above-explained separation manner is applied to the seatback SB. Therefore, even if the rotatable member  20 A is displaced in the axial direction and/or the radial direction of the rotary shaft  42  or displaced in the above-explained separation manner, sticking of the ridge  15  of the opening edge portion  14  with the outer circumferential surface  24  of the rotatable member  20 A never occurs and thereby the noise generation can be prevented. 
     In addition, by providing the escape portion  25 A at the portion on the outer circumferential surface  24  of the rotatable member  20 A that faces to the opening edge portion  14  of the ring-shaped outer circumferential portion  11 A, a width (a height from the circular depressed portion  12  of the ring-shaped outer circumferential portion  11 A) within which an inner circumferential surface of the ring-shaped outer circumferential portion  11 A slidably contacts with the outer circumferential surface  24  of the rotatable member  20 A can be made larger. Therefore, rotations of the rotatable member  20 A within the ring-shaped outer circumferential portion  11 A can be made stable, and stability in strength and prevention of rattling can be also achieved. 
     Further, since the outer circumferential surface  24 , the escape portion  25 A and the sloped portion  26  form a smoothly-continuous surface, sticking of the ridge  15  of the opening edge portion  14  with the outer circumferential surface  24  of the rotatable member  20 A can be further avoided and thereby the noise generation can be further prevented. 
     Note that, in the seat recliner  1  according to the present embodiment, the holder  30 A is fixed with the base member  10 A by swaging the holder  30 A to form the base-side restriction portion  32 . However, in a seat recliner  1 A according to a modified example of the first embodiment as shown in  FIG. 4 , the holder  30 A may be fixed with the base member  10 A by fixing (e.g. laser-welding) the main body  31  with the outer circumferential surface of the ring-shaped outer circumferential portion  11 A without forming the base-side restriction portion  32 . According to the present modified example, the above-explained advantages achieved by the above first embodiment can be also achieved. 
     In the above first embodiment, the escape portion  25 A is formed on the outer circumferential surface  24  of the rotatable member  20 A. However, the escape portion  25 A may be formed at the opening edge portion  14  of the ring-shaped outer circumferential portion  11 A. According to this configuration, the above-explained advantages achieved by the above first embodiment can be also achieved. 
     In the above first embodiment, the diameter r 25  of the escape portion  25 A from the center O of the rotary shaft  42  is made constant so that the escape portion  25 A is made parallel to the outer circumferential surface  24 . However, the escape portion  25 A is formed as a tapered surface so that the diameter r 25  is made gradually reduced from a front-surface side to the rear-side surface of the base member  10 A. According to this configuration, the above-explained advantages achieved by the above first embodiment can be also achieved. 
     A seat recliner  1 B according to a second embodiment will be explained with reference to  FIG. 5 . An escape portion  25 B of a rotatable member  20 B in the seat recliner  1 B according to the present embodiment is different from the escape portion  25 A in the above first embodiment. Note that elements identical or equivalent to those in the above first embodiment are labelled with identical reference numbers, and thereby their redundant explanations are omitted. 
     In the above first embodiment, the escape portion  25 A is formed on the outer circumferential surface  24  of the rotatable member  20 A from its portion facing to the opening edge portion  14  to its plate outer-surface (rear-side surface). However, the escape portion  25 B in the present embodiment is formed on the outer circumferential surface  24  of the rotatable member  20 A only at a portion facing to the opening edge portion  14 . Namely, the escape portion  25 B is formed at the middle of the outer circumferential surface  24  as a depressed groove along a circumferential direction. 
     According to the above-explained configuration of the escape portion  25 B, the above-explained advantages achieved by the above first embodiment can be also achieved. In addition, a rear-side (plate outer-surface side) diameter of the ring-shaped slidably-contact portion  21 A of the rotatable member  20 A is not reduced by the escape portion  25 B, so that a contact portion of the ring-shaped slidably-contact portion  21 A with the rotatable-side restriction portion  33  is not made small but has a sufficient volume. Therefore, sliding stability and anti-separation strength (in the axial direction) of the base member  10 A and the rotatable member  20 A can be improved. 
     A seat recliner  1 C according to a third embodiment will be explained with reference to  FIG. 6 . A base member  10 C (as an inner case) and a rotatable member  20 C (as an outer case) in the seat recliner  1 C according to the present embodiment are different from the base member  10 A (as an outer case) and the rotatable member  20 A (as an inner case) in the above first embodiment. Namely, a ring-shaped slidably-contact portion  21 C of the rotatable member  20 C functions as a “ring-shaped protrusion”, and a holder  30 C is swaged with an outer circumference of the ring-shaped slidably-contact portion  21 C. Note that elements identical or equivalent to those in the above first embodiment are labelled with identical reference numbers, and thereby their redundant explanations are omitted. 
     A escape portion  16 C is formed on an outer circumferential surface  17  of the base member  10 C that faces an opening edge portion  14  on an inner circumferential surface of the ring-shaped slidably-contact portion  21 C that is protruded in a thickness direction and formed on a circumference of the rotatable member  20 C. In addition, the diameter r 25  of the escape portion  16 C is made constant so that the escape portion  16 C is made parallel to the outer circumferential surface  17 , similarly to the configuration in the above first embodiment. 
     According to the above-explained configuration of the escape portion  16 C, the above-explained advantages achieved by the above first embodiment can be also achieved. 
     The present invention is not limited to the above-described embodiments, and it is possible to embody the present invention by modifying its components in a range that does not depart from the scope thereof. Further, it is possible to form various kinds of inventions by appropriately combining a plurality of components disclosed in the above-mentioned embodiments. For example, it may be possible to omit several components from all of the components shown in the above-mentioned embodiments.