Reclining device

Abstract

To provide a reclining device which is capable of preventing a force from being given in the direction in which a ring and a cam bring down a boss with respect to a cylindrical boss part, reducing deformation due to the force given by the cam and the ring, and keeping strength.SOLUTION: A reclining device 100 includes: an external tooth gear 10 where external teeth 11 are formed; an internal gear 20 having internal teeth 21 engageable with the external teeth; a rotary shaft part 31; an outer peripheral wall part; and a bottom surface part arranged between the rotary shaft part and the outer peripheral wall part. The reclining device is provided with: a rotary bush 30 where a center of the rotary shaft part and a center of the outer peripheral wall part are formed eccentrically and which has a cam housing part 34 between a cylindrical boss 22 and the outer peripheral wall part; a pair of wedged cams 50 housed in the cam housing part; and an elastic body 60 energizing the pair of wedged cams in a direction to bring the cams into contact with the rotary bush and the cylindrical boss at the same time.SELECTED DRAWING: Figure 2

Description

[Technical field]

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

[0002] The right holder has developed a seat reclining device that holds a seat back tiltably relative to a seat cushion, as follows: a first frame fixed to either the seat cushion or the seat back; a second frame fixed to the other of the seat cushion and the seat back; an external gear connected to the first frame and having external teeth formed on an outer circumferential surface; an internal gear connected to the second frame and capable of meshing with the external teeth, the internal teeth having a greater number of teeth than the external teeth; 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 a gear shaft of the other external gear, The external gear is formed with an external tooth side restriction portion extending in the axial direction from a vicinity of a part of the external teeth, A reclining device has been proposed in which the internal gear has an internal tooth side regulating portion formed near a portion of the internal teeth that abuts against the external tooth side regulating portion at a predetermined relative rotation regulating position when the external tooth gear and the internal gear rotate relative to each other, thereby regulating the relative rotation within a certain range (Patent Document 1).

[0003] However, such conventional reclining device 300 had a problem in that, as shown in FIG. 8, when a large force is applied to cam 330 or ring 340, a force is applied to cam 330 or ring 340 such that it tends to knock down boss 350, and a large load is applied to the base of boss 350, causing boss 350 to deform and fall over. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2011-207253 A Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention has been made in consideration of these problems, and has an object to provide a reclining device that prevents force from being applied to the cylindrical boss portion in a direction in which the ring or cam would tilt the boss, reduces deformation due to the force applied from the cam or ring, and maintains strength. [Means for solving the problem]

[0006] In order to achieve the above object, the present invention employs the following means.

[0007] The reclining device of the present invention is a seat reclining device that holds a seat back frame constituting a seat back so as to be tiltable 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 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 rotating bushing including a rotating shaft portion formed coaxially and rotatably on the cylindrical boss of the internal gear, an outer peripheral wall portion having an outer periphery the same as the inner periphery of the through hole of the external gear, and a bottom surface portion disposed between the rotating shaft portion and the outer peripheral wall portion, the center of the rotating shaft portion and the center of the outer peripheral wall portion being formed eccentrically, and a cam accommodating portion being formed between the cylindrical boss and the outer peripheral wall portion; a pair of wedge-shaped cams that are accommodated in the cam accommodating portion and press against the cylindrical boss of the internal gear and an inner peripheral surface of an outer peripheral wall portion of the rotating bush to restrict relative rotation between the external gear and the internal gear, and that rotate the rotating bush to cause sliding between the rotating bush and the cylindrical boss of the internal gear or between the rotating bush and the inner peripheral surface of the through hole of the external gear to allow relative rotation between the external gear and the internal gear; an elastic body that biases the pair of wedge-shaped cams in a direction to simultaneously contact the rotating bush and the cylindrical boss; The present invention is characterized in that it is provided with:

[0008] By adopting such a configuration, even if an external force is applied to the rotating bush and the wedge-shaped cam, the use of a rotating bush having a bottom surface that is positioned between the rotating shaft portion and the outer peripheral wall portion prevents the outer peripheral wall portion and the wedge-shaped cam from collapsing, and the load is more easily applied to the base of the cylindrical boss, thereby reducing the amount by which the cylindrical boss collapses and enhancing the rigidity and strength in the direction in which the outer peripheral wall portion and the wedge-shaped cam collapse.

[0009] Further, the present invention provides a reclining device for a seat that holds a seat back frame constituting a seat back so as to be tiltable relative to a seat cushion frame constituting a seat cushion, the reclining device comprising: 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 formed in the center; a rotating bushing including a rotating shaft portion formed coaxially and rotatably on the cylindrical boss of the external gear, an outer peripheral wall portion having an outer periphery the same as the inner periphery of the through hole of the internal gear, and a bottom surface portion disposed between the rotating shaft portion and the outer peripheral wall portion, the center of the rotating shaft portion and the center of the outer peripheral wall portion being formed eccentrically, and a cam accommodating portion being formed between the cylindrical boss and the outer peripheral wall portion; a pair of wedge-shaped cams that are accommodated in the cam accommodating portion and press against the cylindrical boss of the external gear and the inner peripheral surface of the outer circumferential wall portion of the rotating bush to restrict relative rotation between the external gear and the internal gear, and that rotate the rotating bush to slide between the rotating bush and the cylindrical boss of the external gear or between the rotating bush and the inner peripheral surface of the through hole of the internal gear to allow relative rotation between the external gear and the internal gear; an elastic body that biases the pair of wedge-shaped cams in a direction to simultaneously contact the rotating bush and the cylindrical boss; The present invention is characterized in that it is provided with:

[0010] Similarly, with this configuration, even if an external force is applied to the rotating bush and the wedge-shaped cam, by using a rotating bush having a bottom surface that is positioned between the rotating shaft portion and the outer peripheral wall portion, the outer peripheral wall portion and the wedge-shaped cam are prevented from collapsing, and the load is more easily applied to the base of the cylindrical boss, thereby reducing the amount by which the cylindrical boss collapses and enhancing the rigidity and strength in the direction in which the outer peripheral wall portion and the wedge-shaped cam collapse.

[0011] In the reclining device according to the present invention, a hole for inserting a wedge-shaped cam may be provided in the bottom surface at a position corresponding to the cam accommodating portion.

[0012] By adopting such a configuration, the wedge-shaped cam can be attached through the wedge-shaped cam insertion hole even after the rotating bush has been assembled, and the wedge-shaped cam can be replaced during maintenance without removing the rotating bush. [Brief description 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. [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 rotating bush 30 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 showing the internal structure of the reclining device 100 according to the second embodiment. [Figure 8] FIG. 8 is a cross-sectional view showing the internal structure of a conventional reclining device 300. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] 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.

[0015] (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 center position of tilting of a seat back 220 that is tiltably attached to the seat cushion 210, 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 "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 rotating bush 30, a pair of wedge-shaped cams 50a, 50b (50), 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.

[0017] 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 is provided with a protrusion 13 on its outer surface 10b, and the external gear 10 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.

[0018] The internal gear 20 is formed in a disk shape having a larger diameter than the external gear 10, and has a cylindrical recess formed therein so that the external gear 10 can be mounted thereon, with internal teeth 21 formed on the inner peripheral 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, and the external gear 10 and the internal gear 20 are each located at the center C of the external gear 10 as shown in FIG. 2 and the center C of the internal gear 20 1The internal teeth 21 and the external teeth 11 are eccentrically meshed with each other. 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. That is, for example, if there is only one difference in tooth, the external gear 10 will rotate by one tooth when it makes one revolution around the internal gear 20. A cylindrical boss 22 is provided at the center of the internal gear 20. As shown in FIG. 3, a protrusion 23 is also provided on the outer surface of the internal gear 20, and is attached by welding or the like in a state where it is fitted into a fitting hole provided in a mounting plate or the like 230.

[0019] The rotating bush 30 has a rotating shaft portion 31 formed coaxially and rotatably on the cylindrical boss 22 of the internal gear 20, a cylindrical outer circumferential wall portion 32 arranged between 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, and a bottom surface portion 33 supporting the rotating shaft portion 31 and the outer circumferential wall portion 32. The rotating shaft portion 31 is driven to rotate when adjusting the tilt of the seat back 220, and has an inner cylinder provided with serrations 31a for receiving the rotational force of the tilt motor. As shown in FIG. 5B, the rotating bush 30 has a center C of the inner circumferential surface 32b of the outer circumferential wall portion 32. 3 and the center C with respect to the outer peripheral surface 32a 4The outer peripheral wall portion 32 is formed in a ring shape with an eccentricity (γ) between the inner peripheral surface 32b of the outer peripheral wall portion 32 and the cylindrical boss 22 of the internal gear 20. The inner peripheral surface 32b of the outer peripheral wall portion 32 has a diameter slightly larger than that of the outer peripheral surface 22a of the cylindrical boss 22 of the internal gear 20, and the outer peripheral surface 32a of the outer peripheral wall portion 32 is formed to have a diameter slightly smaller than that of the through hole 12 of the external gear 10. In the locked state, a gap A is formed between the inner peripheral surface 32b of the outer peripheral wall portion 32 and the outer peripheral surface 22a of the cylindrical boss 22. The gap A is preferably set to about 0.06 mm to 0.12 mm. A gap B is formed between the outer peripheral surface 32a of the rotating bush 30 and the through hole 12 of the external gear 10. The gap B is preferably set to about 0.02 mm to 0.06 mm. In this case, in order to mesh the external gear 10 and the internal gear 20, the relationship between the gap A and the gap B needs to be gap A>gap B. That is, the gap A between the outer peripheral surface 22a of the cylindrical boss 22 of the internal gear 20 and the inner peripheral surface 32b of the rotating bush 30 is set to be larger than the gap B between the inner peripheral surface 12a of the through hole 12 of the external gear 10 and the outer peripheral surface 32a of the rotating bush 30. The bottom surface portion 33 is a member that connects the rotating shaft portion 31 and the outer peripheral wall portion 32 to each other, and has the function of maintaining the relative positions of the rotating shaft portion 31 and the outer peripheral wall portion 32, as well as the function of preventing the outer peripheral wall portion 32 from deforming so as to fall when force is applied to the outer peripheral wall portion 32.

[0020] Two cam accommodating portions 34 are formed on the inner peripheral surface 32b of the outer peripheral wall portion 32 so that the gap between them gradually narrows from the opposing side. A pair of wedge-shaped cams 50a and 50b (50) are provided in the cam accommodating portion 34 so as to contact the inner peripheral surface of the cam accommodating portion 34 and the outer peripheral surface 22a of the cylindrical boss 22 of the internal gear 20. The wedge-shaped cams 50a and 50b are formed symmetrically with respect to a plane as shown in FIG. 3, and the concave surface 51 (inner surface) of the wedge-shaped cam 50 has the same curved surface as the curved surface of the outer peripheral surface 22a of the cylindrical boss 22, and the convex surface 52 (outer surface) is formed so that the thickness gradually becomes thinner from the opposing side. The cam accommodating portions 34 are provided on both sides of the thickest portion α of the rotating bush 30. The thickest portion has an extension portion 46 extending toward the outer peripheral surface 22a of the cylindrical boss 22. In addition, holes 35a, 35b (35) for inserting wedge-shaped cams may be provided at a position corresponding to the cam accommodating portion 34 on the bottom surface portion 33 so that the wedge-shaped cam 50 can be attached to the cam accommodating portion 34 after the rotating bush 30 is assembled, and can be removed during maintenance.

[0021] 3, the spring 60 has an annular portion 61 and end portions 62a, 62b that rise up so as to be bent at 90° from the annular portion 61, and the end portions 62a, 62b are disposed on the end faces of the thick-walled portions of the wedge-shaped cams 50a and 50b, and are biased in directions in which the wedge-shaped cams 50a and 50b move away from each other. This allows the external gear 10 to be pressed against the internal gear 20 to mesh with it. The spring 60 may be made of another elastic material, such as rubber, as long as it is capable of biasing the wedge-shaped cams 50a and 50b.

[0022] 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 that can hold the spring 60.

[0023] 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.

[0024] The reclining device 100 thus manufactured operates as follows: When no force is applied to the rotating shaft portion 31 and it is not rotating, i.e., when the rotating bush 30 is not rotating, the pair of wedge-shaped cams 50a and 50b are biased by the spring 60 in the direction separating them, and are in contact with the inner peripheral surface 32b of the rotating bush 30 and the outer peripheral surface 22a of the cylindrical boss 22 of the internal gear 20. For this reason, 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.

[0025] When the rotating bush 30 is rotated from this locked state, for example, in a counterclockwise direction in FIG. 2, the rotating bush 30, which is integral with the rotating shaft portion 31, also rotates in the same manner. A wedge angle is set on the inner wall of the cam accommodating portion 34 of the rotating bush 30, and the wedge angle inner wall is in contact with the wedge-shaped cam 50. As the rotating bush 30 rotates, a gap is generated between the wedge angle inner wall and the wedge-shaped cam 50, and the wedge is removed. The rotating bush 30 rotates counterclockwise relative to the internal gear 20, and as a result, a gap is generated between the rotating bush 30 and the cylindrical boss 22 and between the rotating bush 30 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 wedge-shaped cam 50a rotates counterclockwise by the biasing force of the spring 60 so as to fill the gap. The wedge-shaped cam 50 rotates counterclockwise so as to slide together with the rotating bush 30. In this way, the external gear 10, the internal gear 20 and the rotating bush 30 constitute a differential gear mechanism. Note that clockwise rotation can also be achieved in the same manner.

[0026] In the reclining device 100 manufactured in this manner, the rotating bush 30 is formed in a ring shape, so that 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 attempt to move in the direction of the external force or the reaction force. However, in the direction of the attempted movement, the rotating bush 30 is sandwiched perpendicularly between the outer surface 22a of the cylindrical boss 22 of the internal gear 20 and the through hole 12 of the external gear 10, and can act as a bearing by minimizing the component force components, thereby stabilizing sliding and ensuring smooth rotation.

[0027] Furthermore, even if an external force is applied to the rotating bush 30 and the wedge-shaped cam 50, by using a rotating bush 30 having a bottom surface portion 33 arranged between the rotating shaft portion 31 and the outer peripheral wall portion 32, even if the cylindrical boss 22 tilts slightly as shown by arrow C in Figure 4, the outer peripheral wall portion 32 and the wedge-shaped cam 50 are prevented from tilting, and since the load is more easily applied to the base of the cylindrical boss 22, the amount by which the cylindrical boss 22 tilts can be reduced, and the rigidity and strength in the direction in which the outer peripheral wall portion 32 and the wedge-shaped cam 50 tilt can be increased.

[0028] Second embodiment A reclining device 100 according to a second embodiment is shown in Fig. 6 or 7. 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 bush 30, the wedge cam 50, and the spring 60 from moving in the axial direction is provided on the outer surface 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 outer surface side of the external gear 10, and is fixed to the end of the outer periphery of the internal gear 20 by welding or the like, thereby restricting the axial movement of the external gear 10.

[0029] The rotating bush 30 and the spring 60 are manufactured to be symmetrical to those of the first embodiment. The rotating bush 30 has an outer peripheral wall portion 32 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. The rotating bush 30 is disposed so as to rotate coaxially with the central axis of the cylindrical boss 14. A pair of wedge-shaped cams 50a and 50b (50) are provided between the inner peripheral surface of the rotating bush 30 and the outer peripheral surface 14a of the cylindrical boss 14 of the external gear 10 so as to contact both. Two cam accommodating portions 34 are formed on the inner peripheral surface of the rotating bush 30 in accordance with the shape of the wedge-shaped cam 50 so that the gap between them gradually narrows from the opposing side, and the wedge-shaped cam 50 is inserted into the cam accommodating portion 34. The spring 60 has an annular portion 61 and end portions 62a, 62b that rise up so as to be bent 90° from the annular portion 61. The end portions 62a, 62b are disposed on the end faces of the thick-walled portions of the wedge-shaped cams 50a, 50b, and are biased in directions in which the wedge-shaped cams 50a, 50b move away from each other. This allows the external gear 10 to be pressed against the internal gear 20 and engaged with it.

[0030] The inner peripheral surface 32b of the rotating bush 30 has a diameter slightly larger than the diameter of the outer peripheral surface 14a of the cylindrical boss 14, and in the locked state, a gap A' is formed between the inner peripheral surface 32b of the rotating bush 30 and the outer peripheral surface 14a of the cylindrical boss 14. The gap A' between the inner peripheral surface 32b of the rotating bush 30 and the outer peripheral surface 14a of the cylindrical boss 14 is preferably set to approximately 0.06 mm to 0.12 mm. The outer peripheral surface 32a of the rotating bush 30 is disposed in the through hole 25 of the internal gear 20 and is formed to have a diameter slightly smaller than the diameter of the through hole 25 of the internal gear 20, and in the locked state, a gap B' is formed between the outer peripheral surface 32a of the rotating bush 30 and the through hole 25 of the internal gear 20. The gap B' between the outer peripheral surface 32a of the rotating bush 30 and the through hole 25 of the internal gear 20 is preferably set to approximately 0.02 mm to 0.06 mm. At this time, in order to mesh the external gear 10 and the internal gear 20, the relationship between gap A' and gap B' needs to be Gap A' > Gap B'. In other words, the gap B' between the through hole 25 of the internal gear 20 and the rotating bush 30 is set to be smaller than the gap A' between the cylindrical boss 14 of the external gear 10 and the rotating bush 30.

[0031] The reclining device 100 thus manufactured operates as follows: When no force is applied to the rotating bush 30 and it is not rotating, the pair of wedge-shaped cams 50a and 50b are biased by the spring 60 in the direction separating them, and are in contact with 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.

[0032] When the rotating bush 30 is rotated from this locked state, for example, in a counterclockwise direction in FIG. 2, the rotating bush 30, which is integral with the rotating shaft portion 31, also rotates in the same manner. A wedge angle is set on the inner wall of the cam accommodating portion 34 of the rotating bush 30, and the wedge angle inner wall is in contact with the wedge-shaped cam 50. This rotation generates a gap between the wedge angle inner wall and the wedge-shaped cam 50, and the wedge is removed. The rotating bush 30 rotates counterclockwise relative to the internal gear 20, and as a result, a gap is generated between the rotating bush 30 and the cylindrical boss 14 and between the rotating bush 30 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 wedge-shaped cam 50a rotates counterclockwise by the biasing force of the spring 60 so as to fill the gap. The wedge-shaped cam 50 rotates counterclockwise so as to slide together with the rotating bush 30. In this way, the external gear 10, the internal gear 20 and the rotating bush 30 constitute a differential gear mechanism. Note that clockwise rotation can also be achieved in the same manner.

[0033] In the reclining device 100 manufactured in this manner, the rotating bush 30 is formed in a ring shape, so that 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 attempt to move in the direction of the external force or the reaction force. However, in the direction of the attempted movement, the rotating bush 30 is sandwiched perpendicularly between the outer surface 14a of the cylindrical boss 14 of the external gear 10 and the through hole 25 of the internal gear 20, and the component force components are kept to a minimum to act as a bearing, thereby stabilizing sliding and ensuring smooth rotation.

[0034] Furthermore, even if an external force is applied to the rotating bush 30 and the wedge-shaped cam 50, by using a rotating bush 30 having a bottom surface portion 33 arranged between the rotating shaft portion 31 and the outer peripheral wall portion 32, even if the cylindrical boss 22 tilts slightly as shown by arrow C in Figure 4, the outer peripheral wall portion 32 and the wedge-shaped cam 50 are prevented from tilting, and since the load is more easily applied to the base of the cylindrical boss 22, the amount by which the cylindrical boss 22 tilts can be reduced, and the rigidity and strength in the direction in which the outer peripheral wall portion 32 and the wedge-shaped cam 50 tilt can be increased.

[0035] In the first and second embodiments described above, the rotating bush 30 is aligned with the center C 1 and the center C of the external gear 10 2 The eccentricity β of the center C of the rotating bush 30 with respect to the outer circumferential surface 43 3 and the center C of the cylindrical boss hole 41 4 In other words, the rotating bush 30 should be formed so that the eccentricity γ is greater than the eccentricity β.

[0036] Each component of the reclining device 100 varies depending on the manufacturing process, and a gap A is formed between the cylindrical boss hole 41 and the outer circumferential surface 22a of the cylindrical boss 22, and a gap B is formed between the external gear 10 and the through hole 12. This causes a gap between the external teeth 11 of the external gear 10 and the internal teeth 21 of the internal gear 20. Therefore, the center C of the rotating bush 30 with respect to the outer circumferential surface 43 is 3 and the center C of the cylindrical boss hole 41 4 The amount of eccentricity between the center C of the internal gear 20 and 1 and the center C of the external gear 10 2 By forming the eccentricity to be equal to or greater than the amount of eccentricity, it is possible to reduce the occurrence of gaps between the external gear 10 and the external teeth 11 and the internal teeth 21 of the internal gear 20.

[0037] 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]

[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, 10b...outer surface, 11...external teeth, 12...through hole, 12a...inner circumferential surface, 13...projection, 14...cylindrical boss, 14a...outer circumferential surface, 20...internal gear, 20b...outer surface, 21...internal teeth, 22...cylindrical boss, 22a...outer circumferential surface, 23...projection, 25...through hole, 30...rotating bush, 31...rotating shaft portion, 31a...serration, 32...outer circumferential wall portion, 32a...outer circumferential surface, 32b...inner circumferential surface, 33...bottom portion, 34...cam accommodating portion, 35a , 35b, 35...wedge-shaped cam insertion hole, 46...extension portion, 50...wedge-shaped cam, 50a...wedge-shaped cam, 50b...wedge-shaped cam, 51...concave surface, 52...convex surface, 60...spring, 61...annular portion, 62a, 62b...end portion, 70...spring cover, 71...projection 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 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 through hole 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 cylindrical boss formed thereon that is coaxial with the axial direction; a rotating bushing having, integrally, a rotating shaft portion formed coaxially and rotatably on the cylindrical boss of the internal gear, an outer peripheral wall portion having an outer periphery the same as the inner periphery of the through hole of the external gear, and a bottom surface portion disposed between the rotating shaft portion and the outer peripheral wall portion, wherein the center of the inner peripheral surface of the outer peripheral wall portion and the center of the outer peripheral wall portion are formed eccentrically, and a cam accommodating portion is formed between the cylindrical boss and the outer peripheral wall portion; a pair of wedge-shaped cams that are accommodated in the cam accommodating portion and press against the cylindrical boss of the internal gear and the inner peripheral surface of the outer circumferential wall portion of the rotating bush to restrict relative rotation between the external gear and the internal gear, and that rotate the rotating bush to slide between the rotating bush and the cylindrical boss of the internal gear or between the rotating bush and the inner peripheral surface of the through hole of the external gear to allow relative rotation between the external gear and the internal gear; an elastic body that biases the pair of wedge-shaped cams in a direction to simultaneously contact the rotating bush and the cylindrical boss; A reclining device comprising:

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 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 formed in the center; a rotating bushing having, integrally, a rotating shaft portion formed coaxially and rotatably on the cylindrical boss of the external gear, an outer peripheral wall portion having an outer periphery the same as the inner periphery of the through hole of the internal gear, and a bottom surface portion disposed between the rotating shaft portion and the outer peripheral wall portion, the center of the inner peripheral surface of the outer peripheral wall portion and the center of the outer peripheral wall portion being eccentric, and having a cam accommodating portion between the cylindrical boss and the outer peripheral wall portion; a pair of wedge-shaped cams that are accommodated in the cam accommodating portion and press against the cylindrical boss of the external gear and the inner peripheral surface of the outer circumferential wall portion of the rotating bush to restrict relative rotation between the external gear and the internal gear, and that rotate the rotating bush to slide between the rotating bush and the cylindrical boss of the external gear or between the rotating bush and the inner peripheral surface of the through hole of the internal gear, thereby allowing relative rotation between the external gear and the internal gear; an elastic body that biases the pair of wedge-shaped cams in a direction to simultaneously contact the rotating bush and the cylindrical boss; A reclining device comprising:

3. 3. The reclining device according to claim 1, wherein the bottom surface portion is provided with a hole for inserting a wedge-shaped cam at a position corresponding to the cam accommodating portion.

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