Reclining device

Abstract

To provide a reclining device that allows movement of an internal gear and an external gear in an eccentric direction to an extent of ensuring meshing on a side on which the external gear and the internal gear mesh with each other during locking, and that can stabilize sliding by making contact with a cylindrical boss of a gear in a large area even during sliding.SOLUTION: A reclining device of the present invention includes: an external gear 10; an internal gear 20; a ring 30 having a wedge-shaped cam housing part on an inner peripheral surface side and a projection part 36 on a front face side; a pair of wedge-shaped cams 50 that allow relative rotation of the external gear 10 and the internal gear 20; a spring insertion part arranged on the front face side of the ring 30 for inserting an end part of the spring 70 between the pair of wedge-shaped cams 50; a bush 45 having a projection notch part for placing the projection part; an energization member 70 energizing the wedge-shaped cams; a driving member 60; and a rotary shaft 40 which rotates the ring 30 by fitting with the driving member 60.SELECTED DRAWING: Figure 3

Description

[Technical Field]

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

[0002] The right holder has a seat reclining device that holds a seat back tiltably relative to a seat cushion, a first frame fixed to one of the seat cushion and the seat back, and a second frame fixed to the other of the seat cushion and the seat back; an externally toothed gear connected to the first frame, having external teeth formed on its outer circumferential surface and an externally toothed boss portion coaxial with the axial direction on its inner circumferential surface; an internal gear connected to the second frame, having internal teeth formed on an outer circumferential surface thereof so as to be meshable with the external teeth, and having a cylindrical boss portion on an inner circumferential surface thereof which is coaxial with the axial direction; a rotation shaft that is coaxially and rotatably fitted to the external gear and that causes one of the external gear and the internal gear to revolve around the gear shaft of the other, a pair of wedge-shaped cams that are interposed between the cylindrical boss portion and the externally toothed boss portion, and that simultaneously contact the cylindrical boss portion side and the externally toothed boss portion to restrict rotation between the cylindrical boss portion and the externally toothed boss portion, and that slide at least one of the cylindrical boss portion side and the externally toothed boss portion side to allow rotation between the cylindrical boss portion and the externally toothed boss portion; a spring member that biases the pair of wedge-shaped cams in a direction that simultaneously brings them into contact with the cylindrical boss portion side and the externally toothed boss portion side; a disk-shaped member that rotates in accordance with the rotation of the rotary shaft, the disk-shaped member extending in the axial direction and including a pair of cam pushing blades having tapered contact surfaces that push the pair of wedge-shaped cams in a direction away from contact with at least one of the cylindrical boss portion side and the externally toothed boss portion side; The proposed device includes a leaf spring that presses the disk-shaped member against the pair of wedge-shaped cams and causes the tapered contact surface to contact the pair of wedge-shaped cams, and the spring force is set to be weaker than that of the spring material (Patent Document 1).

[0003] According to this reclining device, the wedge-shaped cam is directly operated by the cam pushing blade of a disk-shaped member that is linked to the rotating shaft, which has the effect of making the rotational resistance between the external gear and the internal gear uniform and allowing the external gear and internal gear to rotate smoothly.

[0004] In this type of reclining device, the wedge-shaped cam only contacts the cylindrical boss over a range of less than halfway around the circumference, so when a large force is applied to the seatback of the vehicle seat, the external force acting on the reclining device can only be received at the contact point between the cylindrical boss and the wedge-shaped cam. As a result, if a large force is applied to only a certain part depending on the direction of the external force, the force may have to be received by the gear teeth. However, when the force is received by the gear teeth in this way, a reclining device that is a differential gear cannot smoothly slide and rotate, which is a problem. [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 can stabilize sliding when an external force is applied to the reclining device by having a wedge-shaped cam come into contact with a cylindrical boss depending on the direction of the external force applied. [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 comprises: 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 an outer periphery formed in a circular shape and a center that is eccentric when the inner periphery formed in a portion of the outer periphery is taken as a circle, the ring having a wedge-shaped cam accommodating portion on the inner periphery side and a protrusion on the front side; a pair of wedge-shaped cams that are disposed in wedge-shaped cam accommodating portions of the ring, and that restrict relative rotation between the external gear and the internal gear by contacting the outer peripheral surface of the cylindrical boss of the external gear and the inner peripheral surface of the through hole of the internal gear, and allow relative rotation between the external gear and the internal gear by sliding the outer peripheral surface of the cylindrical boss of the external gear and the inner peripheral surface of the through hole of the internal gear; a bushing disposed on a front side of the ring, the bushing having a spring insertion portion for inserting an end of a spring between the pair of wedge-shaped cams, and a protrusion cutout portion for locating the protrusion; a biasing member that biases the wedge-shaped cams in a direction separating the wedge-shaped cams; a drive member that is coaxially and rotatably fitted into the cylindrical boss of the external gear, and has an engagement hole on the inside and a protrusion on the outer periphery that engages with the protrusion of the ring; a rotating shaft that is fitted to the driving member and rotates the ring via the driving member; The present invention is characterized by the following features.

[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] Furthermore, by stacking them in two layers, the pressure from the wedge-shaped cam can be received at the base of the cylindrical boss, reducing the possibility of the cylindrical boss tilting and preventing the force from the wedge-shaped cam from escaping.

[0011] In addition, in the reclining device according to the present invention, 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 the inner periphery of the through hole of the external gear and the outer periphery of the cylindrical boss of the internal gear, the ring having an outer periphery that is circular and an inner periphery that is partially formed, the center of which is eccentric to the center of which is eccentric when the inner periphery is taken as a circle, the ring having a wedge-shaped cam accommodating portion on the inner periphery side and a protrusion on the front side; a pair of wedge-shaped cams that are disposed in wedge-shaped cam accommodating portions of the ring, and that restrict relative rotation between the external gear and the internal gear by contacting an outer peripheral surface of the cylindrical boss of the internal gear and an inner peripheral surface of the through hole of the external gear, and allow relative rotation between the external gear and the internal gear by sliding the outer peripheral surface of the cylindrical boss of the internal gear and the inner peripheral surface of the through hole of the external gear; a bushing disposed on a front side of the ring, the bushing having a spring insertion portion for inserting an end of a spring between the pair of wedge-shaped cams, and a protrusion cutout portion for locating the protrusion; a biasing member that biases the wedge-shaped cams in a direction separating the wedge-shaped cams; a drive member that is coaxially and rotatably fitted into the cylindrical boss of the internal gear, the drive member having an engagement hole on the inside and a protrusion on the outer periphery that engages with the protrusion of the ring; a rotating shaft that is fitted to the driving member and rotates the ring via the driving member; The present invention is characterized by the following features.

[0012] This invention differs from the above-mentioned inventions in that a cylindrical boss is provided on the internal gear and a through hole is formed in the external gear, 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, thereby preventing rattling in the locked state and stabilizing sliding during sliding, ensuring smooth rotation. [Brief explanation of the drawings]

[0013] [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 cross-sectional view of the reclining device 100 taken along line AA according to the first embodiment. [Figure 5] FIG. 5 is a front view showing the relationship between the ring 30 and the wedge-shaped cam 50 of the reclining device 100 according to the first embodiment. [Figure 6] FIG. 6 is a front view showing the bush 45 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. DETAILED DESCRIPTION OF THE INVENTION

[0014] 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, and FIG. 3 is an exploded perspective view of the reclining device 100. Note that the embodiments and drawings described below exemplify some of the embodiments of the present invention and are not intended to be used for the purpose of limiting the present invention to these configurations. Note that corresponding components in each drawing are assigned the same or similar reference numerals. In addition, in FIG. 3, the directions indicated by the arrows in the drawing are referred to as the "front" and "rear," respectively.

[0015] (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").

[0016] 2 and 3, the reclining device 100 according to the present invention mainly comprises an external gear 10, an internal gear 20, a ring 30, a rotating shaft 40, a bushing 45, a wedge-shaped cam 50, a driving member 60, a spring 70 as an elastic body, and a plate cover 80. Note that the rotating shaft 40 is omitted from Fig. 2 to make the internal structure easier to see.

[0017] As shown in Fig. 3, the external gear 10 is formed in a disk shape, with external teeth 11 formed on the outer circumferential surface and a cylindrical boss 12 provided in the center as shown in Fig. 3. The external gear 10 is provided with a protrusion 13, which is fitted into a fitting hole provided in a mounting plate or the like 230 and is attached to the vehicle seat by welding or the like.

[0018] The internal gear 20 is formed in the shape of a disk 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 (see FIG. 2) are formed on the inner circumferential surface of this recess. The number of internal teeth is at least one more than the number of external teeth 11 of the external gear 10, and 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 the number of 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 through hole 22 is provided at the center of the internal gear 20. This internal gear 20 is provided with a protrusion 23, which is fitted into a fitting hole provided in a mounting plate 230 or the like and is attached to the vehicle seat by welding or the like.

[0019] The ring 30 is an annular member disposed between the inner circumferential surface of the through hole 22 of the internal gear 20 and the outer circumferential surface 12a of the cylindrical boss 12 of the external gear 10. As shown in FIG. 5, the ring 30 is eccentrically formed so that the center C3 of the circularly formed outer circumferential surface 33 and the center C4, assuming that the circularly formed inner circumferential surface 34 covers the entire circumference, are equal to the amount of eccentricity between the centers of the external gear 10 and the internal gear 20. A wedge-shaped cam accommodating portion 35 is formed on the inner circumferential side of the ring 30, and as shown in FIG. 5, is disposed so as to provide a gap between each of a pair of wedge-shaped cams 50 (described later). The ring 30 is preferably formed in contact with the cylindrical boss 12 of the external gear 10 to minimize gaps, and is preferably disposed with respect to the through hole 22 of the internal gear 20 so as to provide 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 fabricating it in this manner, almost the entire circumference of the outer circumferential surface comes into contact with the cylindrical boss 12, which stabilizes sliding and ensures smooth rotation during sliding, while the internal gear 20 can be moved in the eccentric direction by the wedge-shaped cam 50 described below, preventing rattling in the locked state. The ring 30 has two protrusions 36 on opposite sides of the center of the wedge-shaped cam housing portion 35, and a portion of the drive member 60 is engaged between these two protrusions 36, so that the ring 30 moves via the drive member 60 as the rotating shaft 40 rotates.

[0020] 3 or 5, 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 12a of the cylindrical boss 12, 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 near-side ends 53, which are the thicker sides, face each other and, as described above, are disposed in the wedge-shaped cam accommodating portion 35 of the ring 30 so as to contact the inner peripheral surface 22a of the through hole 22 of the internal gear 20.

[0021] The bushing 45 is a component disposed on the front side of the ring 30 and the wedge-shaped cam 50, and is formed in a substantially C-shape as shown in FIG. 6. The outer peripheral surface 46 of the bushing 45 is formed in a circular shape so as to be approximately the same size as the outer peripheral surface of the ring 30, and the inner peripheral surface 47 is formed so as to fit along the inner circumference of the ring 30 and the concave surface 51 of the wedge-shaped cam 50, with the centers of the outer peripheral surface 46 and the inner peripheral surface 47 being eccentric. A concave spring insertion portion 48 is formed in a portion disposed between the respective proximal end portions 53 of the wedge-shaped cams 50a and 50b so that a spring 70 can be inserted into the wedge-shaped cam 50. Furthermore, the C-shaped protrusion cutout portion 49 of the bushing 45 is adapted to receive the protrusion 36 formed on the ring 30.

[0022] The rotating shaft 40 is arranged coaxially with respect to the cylindrical boss 12 of the external gear 10 so as to be able to rotate freely. The rotating shaft 40 is driven to rotate when adjusting the tilt of the seat back 220, and has serrations 41 on its inner cylindrical surface to receive the rotational force of the tilt motor. The rotating shaft 40 has a cylindrical shaft portion 42 that is inserted into a drive member 60 (described later), and is provided with a plurality of locking portions 43 so as to rotate synchronously with the drive member 60.

[0023] The drive member 60 is formed on an outer periphery that is approximately the same thickness as the bushing 45 and is approximately the same size as the inner periphery 47 of the bushing 45, and is disposed on the inner periphery 47 of the bushing 45. A fitting hole 61 is formed on the inner periphery of the drive member 60 so as to fit with the locking portion 43 of the rotating shaft 40, and the drive member 60 is rotated as the rotating shaft 40 rotates. The bushing 45 also has a protrusion 63 that is formed to protrude from an extension portion 62 that extends into the protrusion cutout portion 49 of the bushing 45 and into the two protrusions 36 formed on the ring 30. Therefore, the drive member 60, which is rotated by the rotation of the rotating shaft 40, can rotate by pressing the protrusion 63 against the protrusions 36 of the ring 30.

[0024] 3, the spring 70 serving as the biasing member is made of an elastic body and has an annular portion 71 and end portions 72a and 72b that rise up so as to be bent at 90 degrees from the annular portion 71. The end portions 72a and 72b are in contact with the proximal end portion 53 of the wedge-shaped cam 50, and bias the pair of wedge-shaped cams 50a and 50b in directions that move them apart.

[0025] The plate cover 80 is a member that fixes the external gear 10, the internal gear 20, the ring 30, the rotating shaft 40, the bush 45, the wedge-shaped cam 50, the driving member 60, and the spring 70 as an elastic body so that they do not come off, and its shape is not particularly limited.

[0026] The ring 30 and bushing 45 configured as described above are arranged in two layers in the space formed between the cylindrical boss 12 of the external gear 10 and the through hole 22 of the internal gear 20, with the ring 30 and bushing 45 in that order from the back side. On the ring 30 side, a pair of wedge-shaped cams 50 are arranged in each wedge-shaped cam accommodating portion 35. On the bushing 45 side, the drive member 60 is arranged so that the protrusion 63 on the inner circumferential side is arranged between the protrusions 36, and then the ends 72a, 72b of the spring 70 are arranged via the spring insertion portion 48 so that the pair of wedge-shaped cams 50a and 50b are directed away from each other, and the rotating shaft 40 is fitted into the drive member 60 for assembly.

[0027] The reclining device 100 thus manufactured operates as follows: When no force is applied to the rotating shaft 40 and it is not rotating, the pair of wedge-shaped cams 50a and 50b are urged by the spring 70 in directions separating them, pressing the outer peripheral surface 12a of the cylindrical boss 12 of the external gear 10 against the wedge-shaped cam housing portion 35 of the ring 30, and forcing the ring 30 into pressing contact with the inner peripheral surface 22a of the through-hole 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.

[0028] From this locked state, when the rotating shaft 40 is rotated counterclockwise, for example, as shown in FIG. 2 , the driving member 60 fitted to the rotating shaft 40 rotates first. The rotational force of the driving member 60 is transmitted from the protrusion 63 to the protrusion 36, causing the ring 30 to rotate. At this time, the bushing 45 is also pushed by the protrusion 36 and rotates in the same manner. Due to this rotation, a wedge angle is set between the wedge-shaped cam 50b and the inner wall of the wedge-shaped cam accommodating portion 35 of the ring 30, and the inner wall of the wedge angle is in contact with the wedge-shaped cam 50. As the ring 30 rotates, a gap is created between the inner wall of the wedge angle and the wedge-shaped cam 50, causing the wedge to disengage. As a result, gaps are created between the ring 30 and the cylindrical boss 12 and between the ring 30 and the through-hole 22 of the internal gear 20, allowing the external gear 10 to rotate relative to the internal gear 20. Accordingly, the wedge-shaped cam 50a rotates counterclockwise due to the biasing force of the spring 70, filling the gap. The wedge-shaped cam 50 rotates counterclockwise, sliding together with the rotating shaft 40, ring 30, and bushing 45. In this way, the external gear 10, internal gear 20, and rotating shaft 40 constitute a differential gear mechanism. Clockwise rotation can also be achieved in the same way.

[0029] In the reclining device 100 manufactured in this manner, the ring 30 is formed in a ring shape, and the bush 45 is also formed in an approximately ring shape. Therefore, when an external force is applied to the internal gear 20 or the external gear 10, the internal gear 20 or the external gear 10 will try to move in the direction of the external force or the reaction force, but the bush is sandwiched perpendicular to the outer surface 12a of the cylindrical boss 12 of the external gear 10 and the through hole 22 of the internal gear 20 in the direction of the attempted movement, and the component force components are kept to a minimum and can act as a bearing, stabilizing sliding and ensuring smooth rotation.

[0030] Furthermore, when the rotating shaft 40 is rotated, the protrusion 63 of the bushing 45 is fitted with no gap in the direction of rotation of the protrusion 36, so the gear mechanism can be operated immediately without any time lag. At this time, the ring 30 rotates by being transmitted from the protrusion 63 to the protrusion 36, so that it rotates to follow the eccentric direction of the internal gear 20 and the external gear 10. During rotation, the bushing 45 keeps the ring 30 in contact with most of the outer circumferential surface 12a of the cylindrical boss 12, which stabilizes sliding and ensures smooth rotation. Meanwhile, the wedge-shaped cam 50 biases the external gear 10 to move in the eccentric direction relative to the internal gear 20, preventing rattling in the locked state.

[0031] By arranging the ring 30 and the wedge-shaped cam 50 in two layers in this manner, the ring 30 can ensure contact with the outer peripheral surface 12a of the cylindrical boss 12, and the wedge-shaped cam 50 can maintain the eccentric state of the external gear 10 and the internal gear 20 and separate their respective functions.

[0032] Furthermore, since the cam is positioned on the back side, the pressing force of the cam can be received by the base side of the cylindrical boss 12, as shown in Figure 4, which reduces the load applied to the cylindrical boss 12 and prevents the cylindrical boss 12 from tilting.

[0033] (Second embodiment) An exploded perspective view of a reclining device 100 according to the second embodiment is shown in Figure 7. The reclining device 100 according to the second embodiment is the same as the first embodiment except that a through hole 15 is formed in the external gear 10 and a cylindrical boss 25 is provided on the internal gear 20, and therefore a description thereof will be omitted.

[0034] As shown in FIG. 7, the external gear 10 is formed in a disk shape, with external teeth 11 formed on the outer circumferential surface and a through hole 15 provided in the center.

[0035] The internal gear 20 is formed in the shape of a disk 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, with internal teeth 21 formed on the inner circumferential surface of this recess. The number of internal teeth is at least one more than the number of external teeth 11 of the external gear 10, and the external gear 10 and internal gear 20 are engaged with the internal teeth 21 and external teeth 11 so that the centers of the external gear 10 and internal gear 20 are eccentric, respectively, as in the first embodiment. A cylindrical boss 25 is provided at the center of the internal gear 20, as shown in FIG. 7.

[0036] As in the first embodiment, the reclining device 100 of the second embodiment moves in the following manner: when no force is applied to the rotating shaft 40 and the rotating shaft 40 is not rotating, the pair of wedge-shaped cams 50a and 50b are biased by the spring 70 in directions separating the pair of wedge-shaped cams 50a and 50b, and the inner circumferential surface of the bushing 45 is in contact with the outer circumferential surface 25a of the cylindrical boss 25 of the internal gear 20. Therefore, the relative motion between the internal gear 20 and the external gear 10 is locked, and the seat back 220 is in a locked state. When the rotating shaft 40 is rotated counterclockwise from this locked state, the drive member 60 fitted to the rotating shaft 40 first rotates, and the rotational force of the drive member 60 is transmitted from the protrusion 63 to the protrusion 36, causing the ring 30 to rotate. At this time, the bushing 45 is also pressed by the protrusion 36 and rotates in the same manner. This rotation sets a wedge angle between the wedge-shaped cam 50b and the inner wall of the wedge-shaped cam housing portion 35 of the ring 30, and the inner wall of the wedge angle contacts the wedge-shaped cam 50. As the ring 30 rotates, a gap is created between the wedge-angle inner wall and the wedge-shaped cam 50, causing the wedge to disengage. As a result, gaps are created between the ring 30 and the cylindrical boss 25 of the internal gear 20 and between the ring 30 and the through-hole 15 of the external gear 10, allowing the external gear 10 to rotate 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 70. The wedge-shaped cam 50 rotates counterclockwise, sliding together with the rotating shaft 40, ring 30, and bushing 45. In this way, the external gear 10, the internal gear 20, and the rotating shaft 40 constitute a differential gear mechanism. Clockwise rotation is also possible in the same manner. Clockwise rotation can also be achieved in the same manner.

[0037] 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]

[0038] 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]

[0039] 10...external gear, 11...external teeth, 12...cylindrical boss, 12a...outer peripheral surface, 15...through hole, 20...internal gear, 21...internal teeth, 22...through hole, 22a...inner peripheral surface, 23...projection, 25...cylindrical boss, 25a...outer peripheral surface, 30...ring, 33...outer peripheral surface, 34...inner peripheral surface, 35...wedge-shaped cam accommodating portion, 36...projection, 40...rotating shaft, 41...serration, 42...shaft portion, 43...engaging portion, 45...bush, 46...outer peripheral surface, 47...inner peripheral surface, 48...spring Insertion portion, 49...cutout portion for protrusion portion, 50...wedge-shaped cam, 50a...wedge-shaped cam, 50b...wedge-shaped cam, 51...concave surface, 52...convex surface, 53...proximal end portion, 60...driving member, 61...fitting hole, 62...extension portion, 63...protrusion portion, 70...spring, 71...annular portion, 72a, 72b...end portion, 80...plate cover, 100...recliner device, 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 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 an outer periphery formed in a circular shape and a center that is eccentric when the inner periphery formed in a portion of the outer periphery is taken as a circle, the ring having a wedge-shaped cam accommodating portion on the inner periphery side and a protrusion on the front side; a pair of wedge-shaped cams that are disposed in wedge-shaped cam accommodating portions of the ring, and that restrict relative rotation between the external gear and the internal gear by contacting the outer peripheral surface of the cylindrical boss of the external gear and the inner peripheral surface of the through hole of the internal gear, and allow relative rotation between the external gear and the internal gear by sliding the outer peripheral surface of the cylindrical boss of the external gear and the inner peripheral surface of the through hole of the internal gear; a bushing disposed on a front side of the ring, the bushing having a spring insertion portion for inserting an end of a spring between the pair of wedge-shaped cams and a protrusion cutout portion for locating the protrusion; a biasing member that biases the wedge-shaped cams in a direction separating the wedge-shaped cams; a drive member that is coaxially and rotatably fitted into the cylindrical boss of the external gear, and has an engagement hole on the inside and a protrusion on the outer periphery that engages with the protrusion of the ring; a rotating shaft that is fitted to the driving member and rotates the ring via the driving member; A reclining device comprising:

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 the inner periphery of the through hole of the external gear and the outer periphery of the cylindrical boss of the internal gear, the ring having an outer periphery that is circular and an inner periphery that is partially formed, the center of which is eccentric to the center of which is eccentric when the inner periphery is taken as a circle, the ring having a wedge-shaped cam accommodating portion on the inner periphery side and a protrusion on the front side; a pair of wedge-shaped cams that are disposed in wedge-shaped cam accommodating portions of the ring, and that restrict relative rotation between the external gear and the internal gear by contacting an outer peripheral surface of the cylindrical boss of the internal gear and an inner peripheral surface of the through hole of the external gear, and allow relative rotation between the external gear and the internal gear by sliding the outer peripheral surface of the cylindrical boss of the internal gear and the inner peripheral surface of the through hole of the external gear; a bushing disposed on a front side of the ring, the bushing having a spring insertion portion for inserting an end of a spring between the pair of wedge-shaped cams and a protrusion cutout portion for locating the protrusion; a biasing member that biases the wedge-shaped cams in a direction separating the wedge-shaped cams; a drive member that is coaxially and rotatably fitted into the cylindrical boss of the internal gear, the drive member having an engagement hole on the inside and a protrusion on the outer periphery that engages with the protrusion of the ring; a rotating shaft that is fitted to the driving member and rotates the ring via the driving member; A reclining device comprising:

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