Reclining device

Abstract

To provide a reclining device capable of stabilizing sliding by making it possible to transfer force from any direction of 360° and to make the whole circumference of a bush come into contact at the time of the sliding.SOLUTION: A reclining device 100 comprises an external gear 10, an internal gear 20, a bush 40, a rotation shaft 30, and an elastic body 60. A first bush 41 and a second bush 45 are disposed, in a locked state, so that a gap is provided between the bushes and a cylindrical boss 22 on the side opposite to a side of the cylindrical boss 22 at which the external gear 10 is engaged with the internal gear 20; and are disposed, in a sliding state after the rotation shaft 30 is rotated, so that the gap between the bushes and the cylindrical boss 22 on the side opposite to the side of the cylindrical boss at which the external gear 10 is engaged with the internal gear 20 is reduced.SELECTED DRAWING: Figure 3

Description

[Technical field]

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

[0002] 2. Description of the Related Art There have been various proposals for seat reclining devices that hold a seat back tiltably relative to a seat cushion (for example, see Patent Document 1, etc.). 7, there is a reclining device 300 that includes an external gear 310 having a through hole 312 coaxial with the axial direction on its inner circumferential surface, an internal gear 320 having internal teeth on its outer circumferential surface that can mesh with the external teeth and a cylindrical boss portion coaxial with the axial direction on its inner circumferential surface, a rotating shaft 330 that fits coaxially and rotatably with the external gear 310 and rotates either the external gear 310 or the internal gear 320 around the gear shaft 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 come into contact with the cylindrical boss 322 side and the bushing 340 to regulate the rotation of the cylindrical boss 322 and the bushing 340 and also slide at least one of the cylindrical boss 322 and the bushing 340 to allow the rotation of the cylindrical boss 322 and the bushing 340.

[0003] In a reclining device 300 configured as described above, when the external gear 310 and the internal gear 320 are eccentrically meshed, a gap is required between the bush 340 on the opposite side to the meshed side and the through hole of the external gear 310 (μ) because the external gear 310 needs to move slightly up and down relatively in order to rotate relative to the internal gear 320. Furthermore, it is unavoidable that a gap will occur due to manufacturing errors, etc.

[0004] However, during sliding, the bushes are in contact all around, allowing the force to be transmitted efficiently and acting as bearings, stabilizing the sliding and ensuring smooth rotation. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2019-127210 A 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 has an object to provide a reclining device which, when locked, can form a gap between the bush and the gear on the opposite side to the side where the external gear and internal gear mesh, allowing movement in an eccentric direction due to the meshing of the external gear and internal gear, and which reduces this gap when sliding, allowing contact around the entire circumference of the bush, thereby enabling force to be transmitted from any direction around 360° and stabilizing sliding. [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 holds a seat back frame that constitutes a seat back so as to be tiltable 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 that is directly or indirectly attached to the other of the seat cushion frame and the seat back frame, that has internal teeth that are at least one more than the external teeth on an inner circumferential surface and that can mesh with the external teeth, and that has a cylindrical boss that is coaxial with the axial direction; a first bushing that is disposed between the inner circumference of the through hole of the external gear and the outer circumference of the cylindrical boss of the internal gear, that is formed in an annular shape with the center of the outer circumferential surface formed in a circle and the center of the inner circumferential surface formed in an ellipse eccentrically, and that has a protrusion having a hole for an elastic body on a front surface; and a second bushing that has a hole for an elastic body on a front surface, that is formed in a substantially arch shape with the center of the outer circumferential surface formed in a circle and the center of the inner circumferential surface formed in an ellipse eccentrically, and that is disposed on top of the first bushing so that the protrusion is disposed in the open portion of the annular shape, a rotating shaft that is coaxially and rotatably inserted into the cylindrical boss of the internal gear and has a bush pressing portion that protrudes into the ring opening of the second bush; an elastic body fixed to an elastic body hole of the first bush and an elastic body for biasing the first bush and the second bush, The first bush and the second bush are arranged so that, in a locked state, a gap is provided between them and the cylindrical boss on the opposite side to the side where the external gear and the internal gear mesh, and are arranged so that, when the rotating shaft is rotated and put into a sliding state, the gap between the external gear and the cylindrical boss on the opposite side to the side where the internal gear meshes is reduced.

[0009] By adopting such a configuration, when locked, a gap can be formed between the bush and the gear on the side opposite to the side where the external gear and the internal gear mesh, and when sliding, the bush rotates, the parts of the bush used change between when locked and when sliding, the gap relationship changes, and gaps are provided in different positions in the first bush and the second bush, so that the first bush or the second bush has more contact surfaces over the entire circumference, resulting in a structure that can withstand loads in all directions. Therefore, the bush can support the bearing over almost the entire circumference. Therefore, even if an external force is applied from any direction of 360°, the force can be received by the bush, and sliding can be stabilized.

[0010] Further, the reclining device according to the present invention is A seat reclining device that holds a seat back frame that constitutes a seat back so as to be tiltable 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 an outer peripheral surface on which external teeth are formed and an inner peripheral surface on which a cylindrical boss is formed coaxially with the axial direction; an internal gear that is directly or indirectly attached to the other of the seat cushion frame and the seat back frame, that has internal teeth that are at least one more than the external teeth on an inner circumferential surface and that can mesh with the external teeth, and that has a through hole that is coaxial with the axial direction; a first bushing that is disposed between the inner circumference of the through hole of the internal gear and the outer circumference of the cylindrical boss of the external gear, that is formed in an annular shape with the center of the outer circumferential surface formed in a circle and the center of the inner circumferential surface formed in an ellipse eccentrically, and that has a protrusion having a hole for an elastic body on its back surface; and a second bushing that has a hole for an elastic body on its back surface, that is formed in a substantially arch shape with the center of the outer circumferential surface formed in a circle and the center of the inner circumferential surface formed in an ellipse eccentrically, and that is disposed on top of the first bushing so that the protrusion is disposed in the open portion of the annular shape, a rotating shaft that is coaxially and rotatably inserted into the cylindrical boss of the external gear and has a bush pressing portion that protrudes into the ring opening of the second bush; an elastic body fixed to an elastic body hole of the first bush and an elastic body for biasing the first bush and the second bush, The first bush and the second bush are arranged so that, in a locked state, a gap is provided between the cylindrical boss and the cylindrical boss on the opposite side to the side where the external gear and the internal gear mesh, and are arranged so that, when the rotating shaft is rotated and put into a sliding state, the gap between the cylindrical boss on the opposite side to the side where the external gear and the internal gear mesh is reduced.

[0011] By adopting such a configuration, when locked, a gap can be formed between the bush and the gear on the side opposite to the side where the external gear and the internal gear mesh, and when sliding, the bush rotates, the parts of the bush used change between when locked and when sliding, the gap relationship changes, and gaps are provided in different positions in the first bush and the second bush, so that the first bush or the second bush has more contact surfaces over the entire circumference, resulting in a structure that can withstand loads in all directions. Therefore, the bush can support the bearing over almost the entire circumference. Therefore, even if an external force is applied from any direction of 360°, the force can be received by the bush, and sliding can be stabilized.

[0012] In addition, in the reclining device according to the present invention, The major axes of the ellipses of the first bush and the second bush may be arranged such that, when locked, one of them is out of phase with respect to the eccentric direction of the external gear and the internal gear by +3° to +12° and the other is out of phase with respect to the eccentric direction of the external gear and the internal gear by -3° to -12°.

[0013] By setting the range in this way, it is possible to ensure that as large a surface area as possible comes into contact with the cylindrical boss over the entire circumference during sliding. [Brief description of the drawings]

[0014] [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. [Diagram 2] FIG. 2 is a front view showing the internal structure of the reclining device 100 according to the first embodiment. [Diagram 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 taken along line AA in FIG. 2 according to the first embodiment. [Diagram 5] FIG. 5 is a schematic diagram illustrating the first bush 41 and the second bush 45 according to the first embodiment. [Figure 6] FIG. 6 is an exploded perspective view of the reclining device 100 according to the second embodiment. [Figure 7] FIG. 7 is a front view of a conventional reclining device 300. As shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, a reclining device 100 according to an embodiment of the present invention will be described in detail 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 cross-sectional view taken along line AA in Fig. 2. Note that the embodiments and drawings described below are intended to exemplify a portion 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 the same or similar reference symbols are used for corresponding components in each drawing.

[0016] (First embodiment) 1, the reclining device 100 according to the first embodiment is a device that is attached to a seat cushion 210 of a vehicle seat 200 and a seat back 220 that is tiltably attached to the seat cushion 210 at a central position of the tilting movement, and that provides a tilting function to the seat back 220. Specifically, the reclining device 100 is used by being attached between a seat cushion frame arranged inside the seat cushion 210 and a seat back frame arranged inside the seat back 220 directly or indirectly via another attachment plate 230 (hereinafter referred to as a "mounting plate or the like").

[0017] 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 bush 40, a spring 60 as an elastic body, a spring cover 70, and a plate cover 80. Note that in Fig. 2, the spring cover 70 and the plate cover 80 are omitted in order to make the internal structure easier to see.

[0018] 3, the external gear 10 is formed in a disk shape, with external teeth 11 formed on the outer circumferential surface and a cylindrical through hole 12 formed in the center. The external gear 10 is provided with a protrusion 13 on the front surface 10b, and is attached by welding or the like in a state where it fits into a fitting hole provided in a mounting plate or the like 230.

[0019] The internal gear 20 is formed in a disk shape having a larger diameter than the external gear 10, and a cylindrical recess is formed so that the external gear 10 can be mounted inside, and the internal teeth 21 are formed on the inner peripheral surface of the recess. The internal teeth 21 are formed at least one more than the number of teeth of the external teeth 11 of the external gear 10, and the external gear 10 and the internal gear 20 are engaged 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 shown in FIG. 2. 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, the rotation proceeds by the difference between the teeth of the internal teeth 21 and the external teeth 11. That is, for example, if there is only one difference in tooth, when the external gear 10 makes one revolution around the internal gear 20, it rotates by one tooth. A cylindrical boss 22 is provided at the center of the internal gear 20. As shown in FIG. 3, the internal gear 20 has a protrusion 23 on its back surface, which is fitted into a fitting hole provided in a mounting plate or the like 230 and attached by welding or the like.

[0020] The rotating shaft 30 is coaxially and 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 tilt motor. The rotating shaft 30 is further provided with a bush pressing portion 32 for rotating a first bush 41 and a second bush 45, which will be described later.

[0021] The bush 40 is a component arranged between the outer peripheral surface 22a of the cylindrical boss 22 of the internal gear 20 and the through hole 12 of the external gear 10, and is formed by stacking a first bush 41 and a second bush 45 as shown in Figure 3.

[0022] As shown in Fig. 2B, the first bush 41 is formed in a ring shape in which the center C3 of the inner peripheral surface 41a is offset from the center C4 of the outer peripheral surface 41b. The outer peripheral surface 41b is formed in a circular shape when viewed from the front, and the inner peripheral surface 41a is formed in an elliptical shape. A protrusion 41d having an elastic body hole 41c is provided on the front surface of the first bush 41.

[0023] As shown in Fig. 2C, the second bush 45 is eccentric in that the center of the inner peripheral surface 45a is offset from the center of the outer peripheral surface 45b, similar to the first bush 41. The outer peripheral surface 45b is circular in front view, and the inner peripheral surface 45a is formed in a generally arch shape with a part of the annular shape formed as an ellipse in front view opened. The second bush 45 is placed on top of the first bush 41 on the front side so that the protrusion 41d is located in the open portion. The second bush 45 has an elastic body hole 45c on the front side.

[0024] The spring 60 is made of an elastic body, and as shown in FIG. 3, has an annular portion 61 and end portions 62a and 62b that rise up from the annular portion 61 so as to be bent at 90 degrees.

[0025] The rotating shaft 30, the first bush 41, the second bush 45, and the spring 60 are arranged as the reclining device 100 as follows. If the external gear 10 and the internal gear 20 are locked in a state in which the external gear 10 is eccentric in the direction of the arrow D as shown in Fig. 2A, the first bush 41 contacts the cylindrical boss 22 at a position α in the eccentric direction other than on the line of the arrow D that passes through the center of the external gear 10 as shown in Fig. 2B, thereby locking the external gear 10 and the internal gear 20, and at least at a position β on the line of the arrow D of the cylindrical boss 22 and on the opposite side to the eccentric direction, a gap is provided between the cylindrical boss 22 and the first bush 41, and the external gear 10 can move in the direction of the arrow D and in the opposite direction. The second bush 45 has the protrusion 41d of the first bush 41 disposed in the open ring portion, and as shown in FIG. 2C, the second bush 45 contacts the cylindrical boss 22 at a position γ other than on the line of the arrow D to lock the external gear 10 and the internal gear 20, and has an open ring portion at least at a position δ opposite to the direction of the arrow D on the cylindrical boss 22, and a gap ε is also provided between the end 45d of the second bush 45 and the cylindrical boss 22, so that the external gear 10 can move in the direction of the arrow D and in the opposite direction. Therefore, the external gear 10 and the internal gear 20 can effectively mesh the external teeth 11 and the internal teeth 21. The rotating shaft 30 is attached so that the bush pressing portion 32 is disposed between the protrusion 41d of the first bush 41 and one of the ends of the second bush 45. The elastic body hole 45c of the second bush 45 is provided near the side adjacent to the protrusion 41d of the first bush 41. The spring 60 has ends 62a, 62b inserted into the elastic body hole 41c of the first bush 41 and the elastic body hole 45c of the second bush 45, and is biased so that the first bush 41 and the second bush 45 rotate in opposite directions (in the direction of arrow E in FIG. 2A) as shown in FIG. 2A. This bias brings them into strong contact with the cylindrical boss 22 at positions α and γ, respectively, maintaining the external gear 10 and the internal gear 20 in a locked state.

[0026] As shown in FIG. 4, the spring cover 70 is a cover for holding the spring 60 so that it does not come off, and is not particularly limited as long as it has a shape capable of holding the spring 60.

[0027] The plate cover 80 is formed from a metal plate formed in a circular ring shape and is fixed to the outer end of the internal gear 20 by welding or the like, and has the function of restricting axial movement of the external gear 10.

[0028] The reclining device 100 thus manufactured operates as follows: As described above, in the state of Fig. 2 where no force is applied to the rotating shaft 30 and it is not rotating, the first bush 41 and the second bush 45 are biased by the spring 60 so as to rotate in opposite directions, and due to this bias, they come into strong contact with the cylindrical boss 22 at positions α and γ, respectively, so that the relative movement of the external gear 10 and the internal gear 20 is locked and the seat back 220 is in a locked state.

[0029] When the rotating shaft 30 is rotated clockwise from this locked state, for example, in FIG. 2, the bush pressing portion 32 of the rotating shaft 30 presses the end 45e of the second bush 45, and the second bush 45 rotates clockwise, and the opposite end 45d of the second bush 45 presses the protrusion 41d of the first bush 41, so that the first bush 41 also rotates clockwise. This rotation of the first bush 41 and the second bush 45 creates gaps at the locked positions α and γ, and the rotating shaft 30 and the bush 40 rotate clockwise relative to the internal gear 20. As a result, gaps are created between the bush 40 and the cylindrical boss 22 and between the bush 40 and the through hole 12 of the external gear 10, and the external gear 10 becomes rotatable relative to the internal gear 20. Accordingly, the external gear 10 rotates clockwise to fill the gaps due to the biasing force of the spring 60, and the external gear 10, the internal gear 20, and the rotating shaft 30 form a differential gear mechanism. At this time, the bush 40 rotates during sliding, and the part of the bush 40 used during locking and sliding changes, the gap relationship changes, and gaps are provided at different positions in the first bush 41 and the second bush 45, so that the first bush 41 or the second bush 45 comes into contact with a large surface area over the entire circumference, resulting in a structure that can withstand loads in all directions. 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 tries to move in the direction of the external force or the reaction force, but the bush is sandwiched perpendicularly between the outer circumferential surface 22a of the cylindrical boss 22 of the internal gear 20 and the through hole 12 of the external gear 10 in the direction of the attempted movement, and the component force components are minimized to function as a bearing, so that sliding is stabilized and smooth rotation can be ensured. When the rotating shaft 30 is rotated counterclockwise, the bush pressing portion 32 presses the protrusion 41d of the first bush 41, and the protrusion 41d presses the end 45d of the second bush 45, thereby rotating the shaft counterclockwise. The bush 40 rotates during sliding, and the parts of the bush 40 used during locking and sliding change, the gap relationship changes, and gaps are provided in different positions between the first bush 41 and the second bush 45, just like in the case of clockwise rotation.In this way, in order to provide a gap between the cylindrical boss 22 at position β on the opposite side to the eccentric direction D when locked, and to have as large a surface as possible in contact with the cylindrical boss 22 over the entire circumference when sliding, as shown in Figures 2B and 2C, when locked, the angle θ1 between the major axis 41f of the ellipse of the first bush 41 and the eccentric direction of the external gear 10 and the internal gear (direction of arrow D) and the angle θ2 between the major axis 45f of the ellipse of the second bush 45 and the eccentric direction of the external gear 10 and the internal gear (direction of arrow D) should be arranged so that one is out of phase with the other by +3° to +12° and the other by -3° to -12°.

[0030] Second embodiment A reclining device 100 according to the second embodiment is shown in FIG. 6. The reclining device 100 according to the second 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. Also, a spring cover 70 that prevents the rotating shaft 30, the bush 40, and the spring 60 from moving in the axial direction is provided on the back side of the internal gear 20, and this spring cover 70 is provided with a protrusion 71 that fits into a fitting hole of a mounting plate or the like 230. Meanwhile, the plate cover 80 is made of a metal plate formed into an annular shape, is disposed on the front side of the external gear 10, and is fixed to the end of the external gear 20 on the outer periphery side by welding or the like, thereby restricting the axial movement of the external gear 10.

[0031] The rotating shaft 30, the bushing 40, and the spring 60 are manufactured symmetrically with respect to the first embodiment. The bushing 40 is disposed 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 such that the cylindrical boss 14 is inserted into the inner peripheral surface of the bushing 40. The rotating shaft 30 is disposed within the cylindrical boss 14 so as to rotate coaxially with the central axis of the cylindrical boss 14. Along with Similar to the first embodiment NibuA bush pressing portion 32 is provided, and the bush 40 can be rotated either clockwise or counterclockwise. The bush 40 is formed of a first bush 41 and a second bush 45, and has an outer circumferential surface formed in a circular shape and an inner circumferential surface formed in an elliptical shape, similar to the first embodiment.

[0032] The reclining device 100 thus manufactured operates as follows: As described above, when no force is applied to the rotating shaft 30 and the rotating shaft 30 is not rotating, the first bush 41 and the second bush 45 are biased by the spring 60 so as to rotate in opposite directions, and due to this bias, the first bush 41 and the second bush 45 come into strong contact with the cylindrical boss 22, the relative movement of the external gear 10 and the internal gear 20 is locked, and the seat back 220 is in a locked state.

[0033] When the rotating shaft 30 is rotated clockwise from this locked state, the bush pressing portion 32 of the rotating shaft 30 presses the end 45e of the second bush 45, and the second bush 45 rotates clockwise, and the opposite end 45d of the second bush 45 presses the protrusion 41d of the first bush 41, so that the first bush 41 also rotates clockwise. This rotation of the first bush 41 and the second bush 45 creates a gap at the locked position, and the rotating shaft 30 and the bush 40 rotate clockwise relative to the internal gear 20. As a result, a gap is created between the bush 40 and the cylindrical boss 14 of the external gear 10 and between the bush 40 and the through hole 25 of the internal gear 20, and the external gear 10 becomes rotatable relative to the internal gear 20. Accordingly, the external gear 10 rotates clockwise to fill the gap due to the biasing force of the spring 60, and the external gear 10, the internal gear 20, and the rotating shaft 30 form a differential gear mechanism. At this time, the bush 40 rotates during sliding, and the portion of the bush 40 used during locking and sliding changes, and the gap relationship changes. Since the first bush 41 and the second bush 45 have gaps at different positions, the first bush 41 or the second bush 45 has many surfaces in contact over the entire circumference, and the structure can receive loads in all directions. 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 is moved in the direction of the external force or the reaction force, but the bush is sandwiched perpendicularly between the outer circumferential surface 14a of the cylindrical boss 14 of the external gear 10 and the through hole 25 of the internal gear 20 in the direction of the movement, and the component force components are minimized to function as a bearing, so that sliding is stabilized and smooth rotation can be ensured. The relationship when the rotating shaft 30 is rotated counterclockwise is the same as in the first embodiment.In this way, in order to provide a gap between the cylindrical boss 22 at position β opposite the eccentric direction D when locked, and to ensure that as large a surface as possible contacts the cylindrical boss 22 over the entire circumference when sliding, it is advisable to arrange the angle θ1 between the major axis 41f of the ellipse of the first bush 41 and the eccentric direction of the external gear 10 and the internal gear (direction of arrow D) and the angle θ2 between the major axis 45f of the ellipse of the second bush 45 and the eccentric direction of the external gear 10 and the internal gear (direction of arrow D) so that one is out of phase with the other by +3° to +12° and the other by -3° to -12°.

[0034] It should be noted that the present invention is not limited to the above-described embodiment, and can be embodied in various forms within the technical scope of the present invention. [Industrial Applicability]

[0035] 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]

[0036] 10...external gear, 10b...front surface, 11...external teeth, 12...through hole, 13...projection, 14...cylindrical boss, 14a...outer circumferential surface, 20...internal gear, 21...internal teeth, 22...cylindrical boss, 22a...outer circumferential surface, 23...projection, 25...through hole, 30...rotating shaft, 31...serration, 32...bush pressing portion, 40...bush, 41...first bush, 41a...inner circumferential surface, 41b...outer circumferential surface, 41c...elastic body hole, 41d...projection, 4 Reference Signs List 1f...long shaft, 45...second bush, 45a...inner circumferential surface, 45b...outer circumferential surface, 45c...hole for elastic body, 45d...end, 45e...end, 45f...long shaft, 60...spring, 61...annular portion, 62a, 62b...end, 70...spring cover, 71...projection, 80...plate cover, 100...recliner, 200...vehicle seat, 210...seat cushion, 220...seat back, 230...mounting plate

Claims

1. A seat cushion frame that constitutes a seat cushion is attached to a seat back. A seat reclining device that tiltably holds a seat back frame, 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 that is directly or indirectly attached to the other of the seat cushion frame and the seat back frame, that has internal teeth that are at least one more than the external teeth on an inner circumferential surface and that can mesh with the external teeth, and that has a cylindrical boss that is coaxial with the axial direction; a first bush disposed between the inner circumference of the through hole of the external gear and the outer circumference of the cylindrical boss of the internal gear, formed in an annular shape with the center of the outer circumferential surface formed in a circle and the center of the inner circumferential surface formed in an ellipse eccentrically, and having a protrusion having a hole for an elastic body on a front surface; and a second bush disposed on top of the first bush such that the protrusion is disposed in the open portion of the annular shape with a hole for an elastic body on a front surface, the center of the outer circumferential surface formed in a circle and the center of the inner circumferential surface formed in an ellipse eccentrically, and the second bush is disposed on top of the first bush such that the protrusion is disposed in the open portion of the annular shape, a rotating shaft that is coaxially and rotatably inserted into the cylindrical boss of the internal gear and has a bush pressing portion that protrudes into the annular opening of the second bush; an elastic body fixed to an elastic body hole of the first bush and an elastic body for biasing the first bush and the second bush, respectively; The first bush and the second bush are biased by the elastic body so as to rotate in opposite directions, and come into contact with the cylindrical boss due to this bias.In a locked state in which the relative movement of the external gear and the internal gear is locked, the elastic body biases the first bush and the second bush so that a gap is provided between the cylindrical boss and the cylindrical boss on the opposite side to the side where the external gear and the internal gear are meshed, and when the rotating shaft is rotated and put into a sliding state, the gap between the cylindrical boss on the opposite side to the side where the external gear and the internal gear are meshed is reduced.This reclining device is characterized in that

2. A seat reclining device that holds a seat back frame that constitutes a seat back so as to be tiltable 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 an outer peripheral surface on which external teeth are formed and an inner peripheral surface on which a cylindrical boss is formed coaxially with the axial direction; an internal gear that is directly or indirectly attached to the other of the seat cushion frame and the seat back frame, that has internal teeth on an inner circumferential surface that are at least one more than the external teeth and that can mesh with the external teeth, and that has a through hole that is coaxial with the axial direction; a first bush that is disposed between the inner circumference of the through hole of the internal gear and the outer circumference of the cylindrical boss of the external gear, that is formed in an annular shape with the center of the outer circumferential surface formed in a circle and the center of the inner circumferential surface formed in an ellipse eccentrically, and that has a protrusion having a hole for an elastic body on its back surface; and a second bush that has a hole for an elastic body on its back surface, that is formed in a substantially arch shape with the center of the outer circumferential surface formed in a circle and the center of the inner circumferential surface formed in an ellipse eccentrically, and that is disposed on top of the first bush so that the protrusion is disposed in the open portion of the annular shape, a rotating shaft that is coaxially and rotatably inserted into the cylindrical boss of the external gear and has a bush pressing portion that protrudes into the annular opening of the second bush; an elastic body fixed to an elastic body hole of the first bush and an elastic body for biasing the first bush and the second bush, respectively; The first bush and the second bush are biased by the elastic body so as to rotate in opposite directions, and come into contact with the cylindrical boss due to this biasing.In a locked state in which the relative movement of the external gear and the internal gear is locked, the first bush and the second bush are arranged so that a gap is provided between the cylindrical boss and the cylindrical boss on the opposite side to the side where the external gear and the internal gear are meshed due to the biasing of the elastic body, and when the rotating shaft is rotated and put into a sliding state, the gap between the cylindrical boss on the opposite side to the side where the external gear and the internal gear are meshed is reduced.This reclining device is characterized in that

3. The reclining device according to claim 1 or 2, characterized in that, in a locked state, the major axes of the ellipses of the first bush and the second bush are arranged so that, relative to the eccentric direction of the external gear and the internal gear, one of them is out of phase with each other by +3° to +12° and the other is out of phase with each other by -3° to -12°.

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