Reclining device

Abstract

To provide a reclining device which enables movement in an eccentric direction between an internal tooth gear and an external tooth gear to the extent that the external tooth gear and the internal tooth gear are surely engaged at the time of lock, and can stabilize slide by bringing the member into contact with a cylindrical boss of a gear with a large area even at the time of slide.SOLUTION: A reclining device 100 includes: an external tooth gear 10; an internal tooth gear 20; a ring 40 which is formed so that a center of an outer peripheral surface formed in a circle and a center of an inner peripheral surface formed in a circle are eccentric, and is formed with a through hole for an elastic body; a rotary shaft 30 having a pressing extension part for pressing the ring 40; a pair of wedge-shaped cams 50 arranged on a back face side of the ring 40; and an elastic body 60 for energizing the pair of wedge-shaped cams 50 through the through hole for the elastic body of the ring 40 so as to separate the pair of wedge-shaped cams 50.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a reclining device. [Background technology]

[0002] BACKGROUND ART Various seat reclining devices that hold a seat back tiltably relative to a seat cushion have been proposed (for example, Patent Document 1, etc.). As shown in FIG. 9, one such recliner 300 includes an external gear 310 having a through hole 312 on its inner circumferential surface that is coaxial with the axial direction; an internal gear 320 having internal teeth on its outer circumferential surface that can mesh with the external teeth and a cylindrical boss 322 on its inner circumferential surface that is coaxial with the axial direction; a rotating shaft 330 that is coaxially and rotatably fitted to the external gear 310 and rotates either the external gear 310 or the internal gear 320 around the gear axis of the other; a bushing 340 provided between the through hole 312 and the cylindrical boss 322; and a pair of wedge-shaped cams 350 provided on the bushing 340 that simultaneously contact the cylindrical boss 322 and the bushing 340 to restrict rotation between the cylindrical boss 322 and the bushing 340 and slide at least one of the cylindrical boss 322 and the bushing 340, thereby allowing rotation between the cylindrical boss 322 and the bushing 340.

[0003] In the reclining device 300 configured as described above, when the external gear 310 and the internal gear 320 are eccentrically meshed, the contact point (μ) between the bushing 340 on the side opposite to the meshed side and the through hole 312 of the external gear 310 requires a gap because the external gear 310 must move slightly up and down relative to the internal gear 320 in order for the external gear 310 to rotate relative to the internal gear 320. Even in the locked state, a gap is required to efficiently and reliably mesh the external gear 310 and the internal gear 320 and prevent rattle. However, during sliding, contact around the entire circumference of the bushing allows for efficient transmission of force and serves as a bearing, stabilizing sliding and ensuring smooth rotation, so it is preferable not to leave a gap at this contact point (μ).

[0004] In this way, there was a problem in that a technical contradiction occurred in that a gap was necessary from the viewpoint of the need for rotation and preventing rattle, but no gap was desired for stability during sliding. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2019-127210 Summary of the Invention [Problem to be solved by the invention]

[0006] Therefore, the present invention has been made in consideration of these problems, and aims to provide a reclining device that allows the internal gear and the external gear to move eccentrically to the extent that the meshing sides of the external gear and the internal gear are securely meshed when locked, and that can stabilize sliding even when sliding by having a large area of contact between the member and the cylindrical boss of the gear. [Means for solving the problem]

[0007] In order to achieve the above object, the present invention employs the following means.

[0008] The reclining device of the present invention is a seat reclining device that tiltably holds a seat back frame that constitutes a seat back relative to a seat cushion frame that constitutes a seat cushion, an externally toothed gear attached directly or indirectly to one of the seat cushion frame and the seat back frame, the externally toothed gear having external teeth formed on an outer peripheral surface and a through hole formed coaxially with the axial direction on an inner peripheral surface; an internal gear attached directly or indirectly to the other of the seat cushion frame and the seat back frame, the internal gear having internal teeth on an inner circumferential surface that are capable of meshing with the external teeth, the internal teeth being at least one more than the external teeth, and the internal gear having a cylindrical boss formed thereon that is coaxial with the axial direction; a ring that is disposed between an inner periphery of the through hole of the external gear and an outer periphery of the cylindrical boss of the internal gear, the ring having a circular outer periphery and a circular inner periphery whose centers are eccentric to each other, and has an engaging protrusion or an engaging recess on its front side; a pair of wedge-shaped cams that are arranged on the front side of the ring and contact the outer circumferential surface of the cylindrical boss of the internal gear and the inner circumferential surface of the through hole of the external gear to restrict relative rotation between the external gear and the internal gear, and allow relative rotation between the external gear and the internal gear by sliding the outer circumferential surface of the cylindrical boss of the internal gear and the inner circumferential surface of the through hole of the external gear; a rotating shaft that is coaxially and rotatably fitted into the cylindrical boss of the internal gear, engages with the engaging protrusion or the engaging recess of the ring to rotate the ring, and has a pressing extension that presses the wedge-shaped cam; an elastic body that biases the pair of wedge-shaped cams in directions that move them apart, When the rotary shaft is rotated, the pressing extension portion presses the wedge-shaped cam and then rotates the ring.

[0009] In this invention, by arranging a wedge-shaped cam on the front side of the ring and stacking them in two stages, the functions of the ring, which ensures contact with the cylindrical boss, and the wedge-shaped cam, which moves the external gear in the direction of meshing with the internal gear, are separated. This allows the ring to contact the entire circumference of the cylindrical boss, which serves as a bearing, while moving the external gear toward the internal gear to effectively mesh with it. This stabilizes sliding, ensuring smooth rotation and preventing rattle in the locked state. Furthermore, when rotating the ring, by first pressing the wedge-shaped cam to ensure lock-off and then pressing the ring, operation can be ensured reliably and smoothly.

[0010] In the reclining device according to the present invention, a substantially U-shaped bushing is provided on the outer periphery of the wedge-shaped cam, the wedge-shaped cam restricts relative rotation between the external gear and the internal gear by contacting the outer peripheral surface of the cylindrical boss of the internal gear with the inner peripheral surface of the bushing, and allows relative rotation between the external gear and the internal gear by sliding the bushing and the cylindrical boss of the internal gear or the bushing and the inner peripheral surface of the through hole of the external gear, When the rotary shaft is rotated, the pressing and extending portion may press the bushing and then rotate the ring.

[0011] By adopting this configuration, it is possible to ensure a two-tier configuration in which the ring ensures contact with the cylindrical boss and the wedge-shaped cam ensures meshing between the internal gear and the external gear, while reducing the time lag for the movement of the wedge-shaped cam and enabling quick operation.In addition, when rotating the ring, by reliably rotating the bushing first, the wedge-shaped cam is locked off, and then the ring is pushed, allowing for reliable and smooth operation.

[0012] Further, in the reclining device according to the present invention, a seat reclining device is provided which tiltably holds a seat back frame constituting a seat back relative to a seat cushion frame constituting a seat cushion, an externally toothed gear attached directly or indirectly to one of the seat cushion frame and the seat back frame, the externally toothed gear having external teeth formed on an outer peripheral surface and a cylindrical boss formed coaxially with the axial direction on an inner peripheral surface; an internal gear attached directly or indirectly to the other of the seat cushion frame and the seat back frame, the internal gear having internal teeth on an inner circumferential surface that are capable of meshing with the external teeth, the internal teeth being at least one more than the external teeth, and having a through hole formed therein that is coaxial with the axial direction; a ring that is disposed between an inner periphery of the through hole of the internal gear and an outer periphery of the cylindrical boss of the external gear, the ring having a circular outer periphery and a circular inner periphery whose centers are eccentric to each other, and has an engaging protrusion or an engaging recess on its front side; a pair of wedge-shaped cams that are arranged on the front side of the ring and contact the outer circumferential surface of the cylindrical boss of the external gear and the inner circumferential surface of the through hole of the internal gear to restrict relative rotation between the external gear and the internal gear, and allow relative rotation between the external gear and the internal gear by sliding the outer circumferential surface of the cylindrical boss of the external gear and the inner circumferential surface of the through hole of the internal gear; a rotating shaft that is coaxially and rotatably fitted into the cylindrical boss of the external gear, that engages with the engaging protrusion or the engaging recess of the ring to rotate the ring, and that has a pressing extension that presses the wedge-shaped cam; an elastic body that biases the pair of wedge-shaped cams in directions that move them apart, When the rotary shaft is rotated, the pressing extension portion presses the wedge-shaped cam and then rotates the ring.

[0013] This invention differs from the above-mentioned inventions in that the external gear is provided with a cylindrical boss and the internal gear is formed with a through hole, but similarly, by using a two-tiered configuration with a wedge-shaped cam positioned in front of the ring, the functions of the ring that ensures contact with the cylindrical boss and the wedge-shaped cam that moves the external gear in the direction of meshing with the internal gear are separated, preventing rattling in the locked state and stabilizing sliding during sliding, ensuring smooth rotation. Furthermore, when rotating the ring, by reliably pressing the wedge-shaped cam first to lock off and then pushing the ring, operation can be made reliable and smooth.

[0014] In addition, in the reclining device according to the present invention, A substantially U-shaped bush is provided on the outer periphery of the wedge-shaped cam, the wedge-shaped cam restricts relative rotation between the external gear and the internal gear by contacting the outer circumferential surface of the cylindrical boss of the external gear with the inner circumferential surface of the bushing, and allows relative rotation between the external gear and the internal gear by sliding the bushing against the cylindrical boss of the external gear or the bushing against the inner circumferential surface of the through hole of the internal gear, When the rotary shaft is rotated, the pressing and extending portion may press the bushing and then rotate the ring.

[0015] This configuration ensures contact with the cylindrical boss by the ring and meshing between the internal gear and external gear by the wedge-shaped cam, while also ensuring a two-tiered configuration that reduces the time lag for movement of the wedge-shaped cam, enabling quick operation.In addition, when rotating the ring, by reliably rotating the bushing first, the wedge-shaped cam is locked off, and then the ring is pushed, allowing for reliable and smooth operation. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is a schematic diagram of a vehicle seat 200 to which a reclining device 100 according to the first embodiment is attached. [Figure 2] FIG. 2 is a front view showing the internal structure of the reclining device 100 according to the first embodiment. [Figure 3] FIG. 3 is an exploded perspective view of the reclining device 100 according to the first embodiment. [Figure 4] FIG. 4 is a front view of the ring 40 according to the first embodiment. [Figure 5] FIG. 5 is a cross-sectional view of the reclining device 100 taken along line AA according to the first embodiment. [Figure 6] FIG. 6 is an exploded perspective view of the reclining device 100 according to the first embodiment. [Figure 7] FIG. 7 is an exploded perspective view of the reclining device 100 according to the second embodiment. [Figure 8] FIG. 8 is an exploded perspective view of the reclining device 100 according to the third embodiment. [Figure 9] FIG. 9 is a front view of a conventional reclining device 300. As shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0017] A reclining device 100 according to an embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a schematic diagram of a vehicle seat 200, FIG. 2 is a front view showing the internal structure of the reclining device 100, FIG. 3 is an exploded perspective view of the reclining device 100, and FIG. 4 is a front view of the ring 40. Note that the embodiments and drawings described below exemplify some of the embodiments of the present invention and are not intended to limit the present invention to these configurations. Note that corresponding components in each drawing are denoted by the same or similar reference numerals. Also, in FIG. 3, as indicated by the arrow in the drawing, the direction toward the external gear 10 is referred to as the "front" and the direction toward the internal gear 20 is referred to as the "rear."

[0018] (First embodiment) 1, the reclining device 100 according to the first embodiment is a device attached to a seat cushion 210 of a vehicle seat 200 at a tilting center position of a seat back 220 that is tiltably attached to the seat cushion 210, and provides a tilting function to the seat back 220. Specifically, the reclining device 100 is attached between a seat cushion frame disposed inside the seat cushion 210 and a seat back frame disposed inside the seat back 220, either directly or indirectly via another attachment plate 230 (hereinafter referred to as "attachment plate or the like").

[0019] 2 and 3, the reclining device 100 according to the present invention mainly comprises an external gear 10, an internal gear 20, a rotating shaft 30, a ring 40, a wedge-shaped cam 50, a spring 60 as an elastic body, a spring cover 70, and a plate cover 80. Note that in FIG. 2, the spring 60, spring cover 70, and plate cover 80 are omitted to make the internal structure easier to see.

[0020] 3, the external gear 10 is formed in a disk shape, with external teeth 11 formed on its outer circumferential surface and a cylindrical through-hole 12 formed in its center. The external gear 10 has a protrusion 13 on its front surface 10b, which is fitted into a fitting hole formed in a mounting plate or the like 230 and is attached to the vehicle seat by welding or the like.

[0021] The internal gear 20 is formed in a disk shape with a larger diameter than the external gear 10, and has a cylindrical recess formed therein so that the external gear 10 can be fitted inside. Internal teeth 21 are formed on the inner circumferential surface of this recess. The number of internal teeth 21 is at least one more than the number of teeth of the external teeth 11 of the external gear 10. As shown in FIG. 2 , the external gear 10 and the internal gear 20 mesh with the internal teeth 21 and the external teeth 11 so that the center C1 of the external gear 10 and the center C2 of the internal gear 20 are eccentric, as indicated by arrow d. Therefore, the external gear 10 and the internal gear 20 form a differential gear, and when the internal gear 20 makes one revolution around the external teeth 11, it rotates by the difference in teeth between the internal teeth 21 and the external teeth 11. In other words, for example, if there is a difference of only one tooth, when the external gear 10 makes one revolution around the internal gear 20, it rotates by one tooth. 3, a cylindrical boss 22 is provided at the center of the internal gear 20. A protrusion 23 is provided on the back surface of this internal gear 20, and is attached to the vehicle seat by welding or the like in a state where it fits into a fitting hole provided in a mounting plate or the like 230.

[0022] The ring 40 is an annular member disposed between the inner peripheral surface 12a of the through hole 12 of the external gear 10 and the outer peripheral surface 22a of the cylindrical boss 22 of the internal gear 20. As shown in FIG. 4, the ring 40 is formed eccentrically so that the center of the circularly formed outer peripheral surface 43 and the center of the circularly formed inner peripheral surface 44 are equal to the amount of eccentricity between the centers of the external gear 10 and the internal gear 20. As shown in FIG. 2, an engaging protrusion 41 is provided on the front side so as to leave a gap between the respective separated end portions 54 of a pair of wedge-shaped cams 50 (described later). The ring 40 is preferably formed in contact with the cylindrical boss 22 of the internal gear 20 to minimize gaps, and is preferably disposed relative to the through hole 12 of the external gear 10 to leave a gap that allows the external gear 10 to move in the eccentric direction between the centers of the external gear 10 and the internal gear 20. By manufacturing it in this manner, the entire outer circumferential surface comes into contact with the cylindrical boss 22, which stabilizes the sliding and ensures smooth rotation during sliding, while the external gear 10 can be moved in the eccentric direction by the wedge-shaped cam 50 described below, preventing rattling when in the locked state.

[0023] The wedge-shaped cams 50a and 50b are formed symmetrically with respect to a plane, with the concave surface 51 (inner surface) of the wedge-shaped cam 50 having the same curve as the curved surface of the outer peripheral surface 22a of the cylindrical boss 22, and the convex surface 52 (outer surface) being formed so that the thickness gradually decreases from the opposing side. The wedge-shaped cams 50a and 50b are arranged so that their proximal ends 53, which are the thicker sides, face each other, and are disposed on the front side of the ring 40, i.e., on the rotating shaft 30 side, between the inner peripheral surface 12a of the through hole 12 of the external gear 10 and the outer peripheral surface 22a of the cylindrical boss 22 of the internal gear 20, as shown in Fig. 5, so as to be in contact with each other. By arranging the ring 40 and the wedge-shaped cam 50 in two layers in this manner, the ring 40 can ensure contact with the outer peripheral surface 22a of the cylindrical boss 22, and the wedge-shaped cam 50 can separate the function of maintaining the eccentric state between the external gear 10 and the internal gear 20 from the function of maintaining the eccentric state between the external gear 10 and the internal gear 20.

[0024] The rotating shaft 30 is coaxially rotatably inserted into the cylindrical boss 22 of the internal gear 20. The rotating shaft 30 is rotated when adjusting the tilt of the seat back 220, and has serrations 31 on its inner cylindrical surface to receive the rotational force of the tilting motor. The rotating shaft 30 is disposed near or in contact with the far-side ends 54 of the pair of wedge-shaped cams 50a, 50b, and has a pressing extension 32 that extends near or in contact with the engaging protrusion 41 of the ring 40. That is, the pressing extension 32 is formed in two locations: between the wedge-shaped cam 50a and the engaging protrusion 41, and between the wedge-shaped cam 50b and the engaging protrusion 41. As a result, by rotating the rotating shaft 30, the wedge-shaped cams 50 and the ring 40 can be pressed and rotated. At this time, for example, as shown in Figure 2, when the rotating shaft 30 is rotated clockwise, the gap g2 between the pressing extension portion 32 and the engaging protrusion 41 of the ring 40 is wider than the gap g1 between the pressing extension portion 32 and the wedge-shaped cam 50a so that the pressing extension portion 32 presses the wedge-shaped cam 50a before the ring 40, and when the rotating shaft 30 is rotated counterclockwise, the gap g4 between the pressing extension portion 32 and the engaging protrusion 41 of the ring 40 is wider than the gap g3 between the pressing extension portion 32 and the wedge-shaped cam 50b so that the pressing extension portion 32 presses the wedge-shaped cam 50b before the ring 40.

[0025] 3, the spring 60 is made of an elastic body and has an annular portion 61 and end portions 62a and 62b that rise up so as to be bent at 90 degrees from the annular portion 61. The end portions 62a and 62b are in contact with the proximal end portion 53 of the wedge-shaped cam 50, and urge the pair of wedge-shaped cams 50a and 50b in directions that move them apart.

[0026] The reclining device 100 thus manufactured operates as follows: When no force is applied to the rotating shaft 30 and the rotating shaft 30 is not rotating, the pair of wedge-shaped cams 50a and 50b are biased by the spring 60 in directions separating them, and are in contact with the inner circumferential surface 12a of the through hole 12 of the external gear 10 and the outer circumferential surface 22a of the cylindrical boss 22 of the internal gear 20. As a result, the relative movement between the internal gear 20 and the external gear 10 is locked, and the seat back 220 is in a locked state.

[0027] When the rotating shaft 30 is rotated counterclockwise from this locked state, for example, as shown in FIG. 2, the wedge-shaped cam 50b is first pressed by the pressed extension 32 of the rotating shaft 30. A wedge angle is set between the wedge-shaped cam 50b and the inner peripheral surface 12a of the through hole 12 of the external gear 10. The pressing of the wedge-shaped cam 50b creates a gap between the wedge-angle inner peripheral surface and the wedge-shaped cam 50b, causing the wedge to disengage. This creates gaps between the wedge-shaped cam 50 and the cylindrical boss 22 and between the wedge-shaped cam 50 and the through hole 12 of the external gear 10, allowing the external gear 10 to rotate relative to the internal gear 20. Furthermore, after the wedge-shaped cam 50b is pressed and the wedge is released, the ring 40 is pressed by the pressed extension 32 of the rotating shaft 30 and rotates counterclockwise relative to the internal gear 20. Accordingly, the wedge-shaped cam 50a rotates counterclockwise to fill the gap due to the biasing force of the spring 60. The wedge-shaped cam 50 rotates counterclockwise so as to slide together with the rotating shaft 30 and ring 40. In this way, the external gear 10, the internal gear 20, and the rotating shaft 30 constitute a differential gear mechanism. Clockwise rotation can also be achieved in the same manner. At this time, the engaging protrusions 41 of the ring 40 are also pressed by the pressed and extended portions 32 and rotate in the same manner, so that the ring 40 rotates to follow the eccentric direction of the internal gear 20 and the external gear 10, and during rotation, the ring 40 comes into contact with most of the outer circumferential surface 22a of the cylindrical boss 22, which stabilizes sliding and ensures smooth rotation. Meanwhile, because the wedge-shaped cam 50 urges the external gear 10 to move in the eccentric direction relative to the internal gear 20, rattle can be prevented from occurring in the locked state.

[0028] In the first embodiment, when the ring 40 is rotated by the rotary shaft 30, the engagement protrusion 41 of the ring 40 is pressed by the pressed and extended portion 32 of the rotary shaft 30 to rotate the ring 40. However, this is not a limitation, and the configuration is not particularly limited as long as the ring 40 is rotatable in accordance with the rotation of the rotary shaft 30. For example, as shown in FIG. 6, the ring 40 may be formed with an engagement recess 42 into which the pressed and extended portion 32 of the rotary shaft 30 can be inserted, so that the ring 40 can rotate in accordance with the rotation of the rotary shaft 30. In this case, as in the above case, the engagement recess 42 must be formed with a long hole to allow rotation so that the wedge-shaped cam 50 rotates first, followed by the rotation of the rotary shaft 30.

[0029] (Second embodiment) An exploded perspective view of the reclining device 100 according to the second embodiment is shown in Figure 7. The reclining device 100 according to the second embodiment has the same configuration as the first embodiment except for the addition of a bushing 90 and the shape and arrangement of the wedge-shaped cam 50, so a description thereof will be omitted.

[0030] The recliner 100 according to the second embodiment differs in that it includes a substantially U-shaped bushing 90 on the convex surface 52 (outer surface) side of the wedge-shaped cam 50. The substantially U-shaped bushing 90 is manufactured in a substantially U-shape, as shown in FIG. 7 . The wedge-shaped cam 50 is formed smaller than that of the first embodiment so that it can fit inside the bushing 90. The wedge-shaped cam 50 restricts relative rotation between the external gear 10 and the internal gear 20 by contacting the outer circumferential surface 22 a of the cylindrical boss 22 of the internal gear 20 with the inner circumferential surface of the bushing 90, while allowing relative rotation between the external gear 10 and the internal gear 20 by sliding between the bushing 90 and the cylindrical boss 22 of the internal gear 20 or between the bushing 90 and the inner circumferential surface of the through hole 12 of the external gear 10. At this time, when the rotating shaft 30 is rotated clockwise, the gap between the pressed-extended portion 32 and the engaging protrusion 41 of the ring 40 is wider than the gap between the pressed-extended portion 32 and the end of the end 91a of the bushing 90 so that the pressed-extended portion 32 presses the end 91a of the bushing 90 before the ring 40, and when the rotating shaft 30 is rotated counterclockwise, the gap between the pressed-extended portion 32 and the engaging protrusion 41 of the ring 40 is wider than the gap between the pressed-extended portion 32 and the end 91b of the bushing 90 so that the pressed-extended portion 32 presses the end 91b of the bushing 90 before the ring 40.

[0031] In the reclining device 100 manufactured as described above, when no force is applied to the rotating shaft 30 and the rotating shaft 30 is not rotating, the pair of wedge-shaped cams 50a and 50b are biased by the spring 60 in directions separating them, and the inner peripheral surface of the bushing 90 contacts the outer peripheral surface 22a of the cylindrical boss 22 of the internal gear 20. Therefore, the relative movement between the internal gear 20 and the external gear 10 is locked, and the seat back 220 is in a locked state.

[0032] When the rotating shaft 30 is rotated counterclockwise from this locked state, for example, the pressed and extended portion 32 of the rotating shaft 30 presses the bushing 90, causing it to rotate in the same manner. A wedge angle is set between the bushing 90 and the inner wall surface, and the inner wall of the wedge angle is in contact with the wedge-shaped cam 50. As the bushing 90 rotates, a gap is created between the inner wall of the wedge angle and the wedge-shaped cam 50, causing the wedge to disengage. The rotating shaft 30 and the bushing 90 rotate counterclockwise relative to the internal gear 20, resulting in gaps being created between the bushing 90 and the cylindrical boss 22 and between the bushing 90 and the through hole 12 of the external gear 10, allowing the external gear 10 to rotate relative to the internal gear 20. After the bushing 90 is pressed and the wedge of the wedge-shaped cam 50b is released, the ring 40 is pressed by the pressed and extended portion 32 of the rotating shaft 30. Accordingly, the wedge-shaped cam 50a rotates counterclockwise to fill the gap due to the biasing force of the spring 60. The wedge-shaped cam 50 rotates counterclockwise to slide together with the rotating shaft 30 and the bushing 90. Note that the wedge-shaped cam 50 can also be rotated clockwise in the same manner.

[0033] The ring 40 ensures contact with the cylindrical boss 22, and the wedge-shaped cam 50 ensures meshing between the internal gear 20 and the external gear 10 in a two-tiered configuration. This provides the same effects as the first embodiment, while reducing the time lag for the movement of the wedge-shaped cam 50 and enabling quick operation in response to the rotational movement of the rotating shaft 30.

[0034] (Third embodiment) A reclining device 100 according to a third embodiment is shown in FIG. 8. The reclining device 100 according to the third embodiment differs from the reclining device 100 according to the first embodiment in that a cylindrical boss 14 is provided at the center of the external gear 10 and a through-hole 25 is provided at the center of the internal gear 20. A spring cover 70 that prevents axial movement of the rotating shaft 30, ring 40, wedge cam 50, and spring 60 is provided on the back side of the internal gear 20, and this spring cover 70 has a protrusion 71 that fits into a fitting hole in a mounting plate or the like 230. Meanwhile, the plate cover 80 is made of an annular metal plate, is positioned on the front side of the external gear 10, and is fixed to the outer peripheral end of the internal gear 20 by welding or the like, thereby restricting axial movement of the external gear 10.

[0035] The rotating shaft 30, ring 40, wedge-shaped cam 50, and spring 60 are arranged symmetrically with respect to the first embodiment. The ring 40 is arranged between the outer peripheral surface 14a of the cylindrical boss 14 of the external gear 10 and the through hole 25 of the internal gear 20, with the cylindrical boss 14 inserted into the inner peripheral surface of the ring 40. The rotating shaft 30 is arranged inside the cylindrical boss 14 so as to rotate coaxially with the central axis of the cylindrical boss 14. As in the first embodiment, a pressing extension 32 is provided that presses the wedge-shaped cam 50a, allowing the wedge-shaped cam 50 to rotate either clockwise or counterclockwise. As in the first embodiment, the pressing extension 32 is formed so as to press the wedge-shaped cam 50a before the ring 40 when the rotating shaft 30 is rotated.

[0036] The reclining device 100 thus manufactured operates as follows: When no force is applied to the rotating shaft 30 and the rotating shaft 30 is not rotating, the pair of wedge-shaped cams 50a and 50b are biased by the spring 60 in directions separating them, and are in contact with the inner circumferential surface 25a of the through hole 25 of the internal gear 20 and the outer circumferential surface 14a of the cylindrical boss 14 of the external gear 10. As a result, the relative movement between the internal gear 20 and the external gear 10 is locked, and the seat back 220 is in a locked state.

[0037] When the rotating shaft 30 is rotated counterclockwise from this locked state, the wedge-shaped cam 50b is pressed by the pressed extension 32 of the rotating shaft 30. A wedge angle is set between the wedge-shaped cam 50b and the inner peripheral surface 25a of the through hole 25 of the internal gear 20. The pressure of the wedge-shaped cam 50b creates a gap between the wedge-angle inner peripheral surface and the wedge-shaped cam 50b, causing the wedge to disengage. This creates gaps between the wedge-shaped cam 50 and the cylindrical boss 14 and between the wedge-shaped cam 50 and the through hole 25 of the internal gear 20, allowing the external gear 10 to rotate relative to the internal gear 20. Furthermore, the ring 40 rotates counterclockwise relative to the internal gear 20, and the biasing force of the spring 60 causes the wedge-shaped cam 50a to rotate counterclockwise to fill the gap. The wedge-shaped cam 50 rotates counterclockwise so as to slide together with the rotary shaft 30 and the ring 40. It should be noted that the wedge-shaped cam 50 can also be rotated clockwise in the same manner.

[0038] The reclining device 100 thus manufactured is in contact with the outer surface 14a of the cylindrical boss 14 by the ring 40, which stabilizes the sliding movement and ensures smooth rotation during sliding, and the wedge-shaped cam 50 urges the external gear 10 to move in an eccentric direction relative to the internal gear 20, preventing rattling when locked.

[0039] In the third embodiment, similarly to the second embodiment, a substantially U-shaped bushing 90 may be provided on the convex surface 52 (outer surface) side of the wedge-shaped cam 50. In this case, the pressed extension portion 32 is formed so as to press the bushing 90a before the ring 40 when the rotating shaft 30 is rotated.

[0040] The present invention is not limited to the above-described embodiment, and can be embodied in various forms as long as they fall within the technical scope of the present invention. [Industrial Applicability]

[0041] As shown in the above-described embodiment, the present invention is industrially applicable mainly as a reclining device for a vehicle seat. [Explanation of symbols]

[0042] 10...externally toothed gear, 10b...front surface, 11...external teeth, 12...through hole, 12a...inner peripheral surface, 13...protrusion, 14...cylindrical boss, 14a...outer peripheral surface, 20...internal gear, 21...internal teeth, 22...cylindrical boss, 22a...outer peripheral surface, 23...protrusion, 25...through hole, 25a...inner peripheral surface, 30...rotating shaft, 31...serration, 32...pressed extension portion, 40...ring, 41...engaging protrusion, 42...engaging recess, 43...outer peripheral surface, 44...inner peripheral surface, 50...wedge-shaped cam, 50a...wedge-shaped cam, 50b...wedge-shaped cam, 51...concave surface, 52...convex surface, 53...proximal end, 54...remote end, 60...spring, 61...annular portion, 62a, 62b...end, 70...spring cover, 71...projection, 80...plate cover, 90...bush, 91a, 91b...end, 100...recliner, 200...vehicle seat, 210...seat cushion, 220...seat back, 230...mounting plate

Claims

1. A seat reclining device that tiltably holds a seat back frame that constitutes a seat back relative to a seat cushion frame that constitutes a seat cushion, an externally toothed gear attached directly or indirectly to one of the seat cushion frame and the seat back frame, the externally toothed gear having external teeth formed on an outer peripheral surface and a through hole formed coaxially with the axial direction on an inner peripheral surface; an internal gear attached directly or indirectly to the other of the seat cushion frame and the seat back frame, the internal gear having internal teeth on an inner circumferential surface that are capable of meshing with the external teeth, the internal teeth being at least one more than the external teeth, and the internal gear having a cylindrical boss formed coaxially with the axial direction; a ring that is disposed between an inner periphery of the through hole of the external gear and an outer periphery of the cylindrical boss of the internal gear, the ring having a circular outer periphery and a circular inner periphery whose centers are eccentric to each other, and has an engaging protrusion or an engaging recess on its front side; a pair of wedge-shaped cams that are arranged on the front side of the ring and contact the outer circumferential surface of the cylindrical boss of the internal gear and the inner circumferential surface of the through hole of the external gear to restrict relative rotation between the external gear and the internal gear, and allow relative rotation between the external gear and the internal gear by sliding the outer circumferential surface of the cylindrical boss of the internal gear and the inner circumferential surface of the through hole of the external gear; a rotating shaft that is coaxially and rotatably fitted into the cylindrical boss of the internal gear, engages with the engaging protrusion or the engaging recess of the ring to rotate the ring, and has a pressing extension that presses the wedge-shaped cam; an elastic body that biases the pair of wedge-shaped cams in directions that move them apart, A reclining device, characterized in that, when the rotating shaft is rotated, the pressing extension portion presses the wedge-shaped cam and then rotates the ring.

2. A seat reclining device that tiltably holds a seat back frame that constitutes a seat back relative to a seat cushion frame that constitutes a seat cushion, an externally toothed gear attached directly or indirectly to one of the seat cushion frame and the seat back frame, the externally toothed gear having external teeth formed on an outer peripheral surface and a through hole formed coaxially with the axial direction on an inner peripheral surface; an internal gear attached directly or indirectly to the other of the seat cushion frame and the seat back frame, the internal gear having internal teeth on an inner circumferential surface that are capable of meshing with the external teeth, the internal teeth being at least one more than the external teeth, and the internal gear having a cylindrical boss formed coaxially with the axial direction; a ring that is disposed between an inner periphery of the through hole of the external gear and an outer periphery of the cylindrical boss of the internal gear, the ring having a circular outer periphery and a circular inner periphery whose centers are eccentric to each other, and has an engaging protrusion or an engaging recess on its front side; a substantially U-shaped bushing provided so as to come into contact with an inner peripheral surface of the through hole of the external gear; a pair of wedge-shaped cams that are arranged on the front side of the ring and that restrict relative rotation between the external gear and the internal gear by contacting the outer circumferential surface of the cylindrical boss of the internal gear with the inner circumferential surface of the bushing, and allow relative rotation between the external gear and the internal gear by sliding the bushing and the cylindrical boss of the internal gear or the bushing and the inner circumferential surface of the through hole of the external gear; a rotating shaft that is coaxially and rotatably fitted into the cylindrical boss of the internal gear, engages with the engaging protrusion or the engaging recess of the ring to rotate the ring, and has a pressing extension that presses the wedge-shaped cam; an elastic body that biases the pair of wedge-shaped cams in directions that move them apart, The reclining device, wherein, when the rotating shaft is rotated, the pressing extension portion presses the bushing and then rotates the ring.

3. A seat reclining device that tiltably holds a seat back frame that constitutes a seat back relative to a seat cushion frame that constitutes a seat cushion, an externally toothed gear attached directly or indirectly to one of the seat cushion frame and the seat back frame, the externally toothed gear having external teeth formed on an outer peripheral surface and a cylindrical boss formed coaxially with the axial direction on an inner peripheral surface; an internal gear attached directly or indirectly to the other of the seat cushion frame and the seat back frame, the internal gear having internal teeth on an inner circumferential surface that are capable of meshing with the external teeth, the internal teeth being at least one more than the external teeth, and having a through hole formed therein that is coaxial with the axial direction; a ring that is disposed between an inner periphery of the through hole of the internal gear and an outer periphery of the cylindrical boss of the external gear, the ring having a circular outer periphery and a circular inner periphery whose centers are eccentric to each other, and has an engaging protrusion or an engaging recess on its front side; a pair of wedge-shaped cams that are arranged on the front side of the ring and contact the outer circumferential surface of the cylindrical boss of the external gear and the inner circumferential surface of the through hole of the internal gear to restrict relative rotation between the external gear and the internal gear, and allow relative rotation between the external gear and the internal gear by sliding the outer circumferential surface of the cylindrical boss of the external gear and the inner circumferential surface of the through hole of the internal gear; a rotating shaft that is coaxially and rotatably fitted into the cylindrical boss of the external gear, that engages with the engaging protrusion or the engaging recess of the ring to rotate the ring, and that has a pressing extension that presses the wedge-shaped cam; an elastic body that biases the pair of wedge-shaped cams in directions that move them apart, A reclining device, characterized in that, when the rotating shaft is rotated, the pressing extension portion presses the wedge-shaped cam and then rotates the ring.

4. A seat reclining device that tiltably holds a seat back frame that constitutes a seat back relative to a seat cushion frame that constitutes a seat cushion, an externally toothed gear attached directly or indirectly to one of the seat cushion frame and the seat back frame, the externally toothed gear having external teeth formed on an outer peripheral surface and a cylindrical boss formed coaxially with the axial direction on an inner peripheral surface; an internal gear attached directly or indirectly to the other of the seat cushion frame and the seat back frame, the internal gear having internal teeth on an inner circumferential surface that are capable of meshing with the external teeth, the internal teeth being at least one more than the external teeth, and having a through hole formed therein that is coaxial with the axial direction; a ring that is disposed between an inner periphery of the through hole of the internal gear and an outer periphery of the cylindrical boss of the external gear, the ring having a circular outer periphery and a circular inner periphery whose centers are eccentric to each other, and has an engaging protrusion or an engaging recess on its front side; a substantially U-shaped bushing provided so as to come into contact with an inner peripheral surface of the through hole of the internal gear; a pair of wedge-shaped cams that are arranged on the front side of the ring and that restrict relative rotation between the external gear and the internal gear by contacting the outer circumferential surface of the cylindrical boss of the external gear with the inner circumferential surface of the bushing, and allow relative rotation between the external gear and the internal gear by sliding the bushing and the cylindrical boss of the external gear or the bushing and the inner circumferential surface of the through hole of the internal gear; a rotating shaft that is coaxially and rotatably fitted into the cylindrical boss of the external gear, that engages with the engaging protrusion or the engaging recess of the ring to rotate the ring, and that has a pressing extension that presses the wedge-shaped cam; an elastic body that biases the pair of wedge-shaped cams in directions that move them apart, The reclining device, wherein, when the rotating shaft is rotated, the pressing extension portion presses the bushing and then rotates the ring.

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