Reclining device

Abstract

To provide a configuration properly meshing external teeth of a lock gear and internal teeth of a gear plate even when an angle of the gear plate relative to the lock gear is deviated.SOLUTION: A first movable guide 63 is disposed between a gear lateral surface 61d of a lock gear 61 and a first guide surface 31a provided on a base plate 30, and a second movable guide 64 is disposed between a gear lateral surface 61e and a second guide surface 32a. The first guide surface 31a is formed to be curved in a concave shape such that a distance to the gear lateral surface 61d becomes closer toward the radially inner side, while the second guide surface 32a is formed to be curved in a concave shape such that a distance to the gear lateral surface 61e becomes closer toward the radially inner side. Alternatively, the first movable guide 63 is so formed that the lateral surface 63a pressed by the gear lateral surface 61d comes into surface contact with the gear lateral surface 61d, such that a convex lateral surface 63b pressed by the first guide surface 31a is curved in a convex shape, while the second movable guide 64 is so formed that the lateral surface 64a pressed by the gear lateral surface 61e comes into surface contact with the gear lateral surface 61e, such that a convex lateral surface 64b pressed by the second guide surface 32a is curved in a convex shape.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to a reclining device that adjusts the tilt angle between a first member and a second member that tilt relative to one another. [Background technology]

[0002] A conventional reclining device that adjusts the tilt angle between a first member and a second member that tilt relative to one another is disclosed in Patent Document 1. This reclining device is configured to switch between a locked state, in which the external teeth of the lock gears mesh with the internal teeth of the gear plate, and an unlocked state, in which the meshing is released, depending on the state of contact between a cam that rotates in response to the operation of a reclining operation lever and four lock gears.

[0003] In addition, between the lock gear and the fixed guide, a slidable movable guide is interposed, and the width of each movable guide is gradually narrowed from the outer end to the inner end, and the sliding surface of the movable guide on the lock gear side is parallel to the moving direction of the lock gear, and the sliding surface on the fixed guide side is inclined with respect to the sliding surface on the lock gear side. A spring is engaged with each movable guide, and the spring biases the movable guide inwardly of the base plate. Therefore, the movable guide is always wedged between the lock gear and the fixed guide, and the fixed guide, the lock gear, and the movable guide are mutually engaged, and the gap between each member disappears. This reliably eliminates backlash in the front-rear direction of the seat back, enabling reliable locking and unlocking. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2012-056397 A Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, a meshing state (hereinafter, simply referred to as a fully meshed state) in which the external teeth of the lock gear that has moved in the locking direction along the guide surface provided on the base plate mesh completely without misalignment with the internal teeth of the gear plate exists for each gear tooth pitch. Therefore, if the relative angle between the gear plate and the lock gear deviates from the fully meshed state due to a twist of the seat frame or the like, the external teeth of the lock gear that has moved in the locking direction along the guide surface mesh with the internal teeth of the gear plate in an incompletely meshed state. For example, with a gear tooth pitch of 2° / tooth, if the gear plate deviates by 0.5° relatively from the fully meshed state, the external teeth of the lock gear and the internal teeth of the gear plate do not mesh sufficiently, resulting in insufficient meshing. When such insufficient meshing occurs, not only does the meshing portion or the like become insufficient in strength, but it may also promote frame twisting or the like.

[0006] The present invention has been made to solve the above-mentioned problems, and its object is to provide a configuration that enables the external teeth of the lock gear and the internal teeth of the gear plate to properly mesh even if the relative angle between the gear plate and the lock gear is misaligned. [Means for solving the problem]

[0007] In order to achieve the above object, the invention of claim 1 described in the claims is as follows: A reclining device (20) for adjusting a tilt angle between a first member (11, 11a) and a second member (12, 12a) that tilt relative to one another, comprising: A base plate (30) attached to the first member; a gear plate (40) attached to the second member and assembled to be rotatable relative to the base plate, the gear plate having internal teeth (41); a lock gear (61) assembled to the base plate so as to be slidable in a radial direction and having external teeth (61a) capable of meshing with the internal teeth; a movable guide (63, 64) disposed between a gear side surface (61d, 61e) of the lock gear along a sliding direction and a guide surface (31a, 32a) provided on the base plate; a cam (70) capable of controlling radial movement of the lock gear and biased in a locking direction to cause the external teeth to mesh with the internal teeth; a biasing member (82) that biases the movable guide in a direction pressing the movable guide against both the gear side surface and the guide surface; Equipped with The guide surface is formed to be concavely curved so that the distance between the guide surface and the gear side surface becomes closer toward the inside in the radial direction, The movable guide is characterized in that one side surface (63a, 64a) that is pressed against the gear side surface is in face contact with the gear side surface, and the other side surface (63b, 64b) that is pressed against the guide surface is formed so as to be convexly curved. The symbols in parentheses above indicate the corresponding relationship with the specific means described in the embodiments described later. Effect of the Invention

[0008] In the invention of claim 1, a movable guide is disposed between the gear side surface of the lock gear along the sliding direction and a guide surface provided on the base plate. The guide surface is formed to be concavely curved so that the distance to the gear side surface decreases toward the radially inner side, and the movable guide is formed so that one side surface pressed against the gear side surface is in surface contact with the gear side surface and the other side surface pressed against the guide surface is curved convexly.

[0009] As a result, when the external teeth of the lock gear, which has been moved radially outward by the force in the locking direction from the cam, mesh with the internal teeth of the gear plate, the other convexly curved side surface of the movable guide is guided by the convexly curved guide surface of the base plate. Therefore, when the gear plate and the lock gear mesh with each other in a state where the relative angle between them is deviated from the fully meshed state, the force in the locking direction causes the contact position between the other side surface of the movable guide and the guide surface of the base plate to shift along the curved shape, so that the movable guide and the lock gear are tilted relative to the gear plate so as to eliminate the deviation from the fully meshed state. In other words, even if the relative angle between the gear plate and the lock gear is deviated, the lock gear is tilted to achieve the fully meshed state, so that the external teeth of the lock gear and the internal teeth of the gear plate can be properly meshed with each other.

[0010] In the invention of claim 2, a pair of movable guides and guide surfaces are provided on the left and right sides of the lock gear, and the angle at which the movable guide and lock gear are inclined is increased, thereby enabling the external teeth of the lock gear and the internal teeth of the gear plate to mesh more reliably. [Brief description of the drawings]

[0011] [Figure 1] 1 is a side view showing an outline of the configuration of a vehicle seat on which a reclining device of the present invention is installed. [Diagram 2] FIG. [Diagram 3] FIG. [Figure 4] 3 is a cross-sectional view taken along a line X1-X1 shown in FIG. 2. [Diagram 5] 3 is a cross-sectional view taken along line X2-X2 of FIG. 2. [Figure 6] FIG. 6(A) is an explanatory diagram illustrating the state of the lock gear and both movable guides just before meshing, and FIG. 6(B) is an explanatory diagram illustrating the state of the lock gear and both movable guides in an incomplete meshing state. [Figure 7]FIG. 7(A) is an explanatory diagram illustrating a state in which the lock gear tilts from the state shown in FIG. 6(B) to a fully engaged state, and FIG. 7(B) is an enlarged view showing the area enclosed by the two-dot chain line in FIG. 7(A). BEST MODE FOR CARRYING OUT THEINVENTION

[0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a reclining device according to the present invention will be described with reference to the drawings. As shown in FIG. 1, a vehicle seat 10 equipped with a reclining device 20 of the present invention has as its main components a seat cushion 11 and a seat back 12, with a seat bracket (lower bracket) 11a fixed to the seat cushion 11 and a seat back bracket (upper bracket) 12a fixed to the seat back 12.

[0013] The lower bracket 11a and the upper bracket 12a are fixed to portions of the round reclining unit 21 that rotate relative to each other, and are thereby connected to each other so as to be capable of rotating relative to each other. This makes it possible to adjust the tilt angle of the seat back 12 relative to the seat cushion 11. The seat cushion 11 and the lower bracket 11a can be an example of a "first member," and the seat back 12 and the upper bracket 12a can be an example of a "second member."

[0014] A reclining operation lever 23 is attached to a center shaft 22 in the center of the round reclining unit 21. The round reclining unit 21, the center shaft 22, and the reclining operation lever 23 constitute the reclining device 20. When the reclining operation lever 23 is pulled upward, the reclining device 20 is unlocked, and the tilt angle of the seat back 12 can be adjusted. Here, the range of angle A shown in FIG. 1 when the seat back 12 is tilted backward is the tilt adjustment range in which the seat back 12 is locked at the angle position when the reclining operation lever 23 is released, and the range of angle B shown in FIG. 1 when the seat back 12 is tilted forward is the free rotation range corresponding to the lock-free state in which the unlocked state continues even when the reclining operation lever 23 is released. As can be seen from FIG. 1, the seat back 12 can be rotated from a forward tilt position in which it contacts the seat cushion 11 to a backward tilt position in which it is flat against the seat cushion 11. The structure of such a reclining device 20 will be described below.

[0015] 2 and 3, the round reclining unit 21 is configured by overlapping a substantially disc-shaped base plate 30 and a substantially bowl-shaped gear plate 40 and assembling a cover bracket 50, thereby holding the base plate 30 and the gear plate 40 rotatably relative to each other and suppressing relative movement in the axial direction. For convenience, the center shaft 22 and the reclining operation lever 23 are not shown in Figures 2 and 3, and in Figures 4 and 5, only the vicinity of the internal teeth 41 of the gear plate 40 is shown, with the cover bracket 50 not shown.

[0016] A cavity (space) C is formed between the base plate 30 and the gear plate 40. As shown in Figures 2 to 5, a pair of lock gears 61, a pair of first movable guides 63, and a pair of second movable guides 64, a central cam 70, a pair of spring members 81 and 82, a substantially disk-shaped cam lever 90, and other members for locking and unlocking are disposed in the cavity C. In the following description, the left side of Figure 2 is one axial side, and the right side of Figure 2 is the other axial side.

[0017] The base plate 30 has multiple protrusions 30b formed on one axial side surface (hereinafter also referred to as the mounting surface 30a), and is attached to the lower bracket 11a by engaging each of these protrusions 30b with an engagement hole (not shown) in the lower bracket 11a.

[0018] As shown in FIG. 4, the base plate 30 has four guide protrusions 31, 32, 31, 32 formed on the other axial side for guiding both lock gears 61 in a radially slidable manner. The side surface of the guide protrusion 31 located on the lock gear 61 side (hereinafter also referred to as the first guide surface 31a) and the side surface of the guide protrusion 32 located on the lock gear 61 side (hereinafter also referred to as the second guide surface 32a) are formed to function as a pair of guide surfaces for guiding the lock gear 61 and the movable guides 63, 64. In particular, the first guide surface 31a and the second guide surface 32a are formed to be curved in a concave shape so that the distance to the gear side surface of the lock gear 61 becomes closer toward the inside in the radial direction. The detailed shapes of the first guide surface 31a and the second guide surface 32a will be described later.

[0019] Further, two recesses 36 are formed on the other axial side of the base plate 30 so as to face each other via an insertion hole 35 through which the shaft portion (not shown) of the center shaft 22 is inserted. Both recesses 36 are for accommodating spiral spring members 81, and an engagement piece 36a with which one end side of the spring member 81 is engaged is formed so as to extend from the bottom surface to the other axial side.

[0020] Internal teeth 41 are formed around the entire inner peripheral surface of the gear plate 40. A plurality of protrusions 40a are formed on the back surface (the surface on the other axial side) of the gear plate 40, and the gear plate 40 is attached to the upper bracket 12a by engaging each of these protrusions 40a with an engaging hole (not shown) of the upper bracket 12a.

[0021] Furthermore, two arcuate stepped portions are arranged at 180° intervals on the inner peripheral surface of the gear plate 40, which are formed coaxially with the internal teeth 41. The arcuate stepped portions are intended to realize the above-mentioned lock-free state, and are formed so that the angular range in which a protrusion 61c (described later) of the lock gear 61 abuts from the inner peripheral side corresponds to the above-mentioned free rotation range.

[0022] 3 and 4, external teeth 61a that can mesh with the internal teeth 41 of the gear plate 40 are formed on the outer periphery of the lock gear 61. The lock gear 61 is also provided with a protrusion 61b that protrudes toward the other axial side (gear plate side), and this protrusion 61b functions to control the radial movement of the lock gear 61 by being guided by a rotating cam lever 90 as described later. The lock gear 61 is also provided with a protrusion 61c on the outer side of the protrusion 61b, and this protrusion 61c is formed so as to maintain a state in which the internal teeth 41 and the external teeth 61a are disengaged by abutting against a circular arc-shaped step portion of the gear plate 40 from the inner periphery side.

[0023] The lock gear 61 is positioned between the first guide surface 31a of the guide bulge 31 and the second guide surface 32a of the guide bulge 32, with the lock gear 61 clamped so that its approximately planar gear side surfaces 61d, 61e along the sliding direction are in face contact with both the movable guide 63 and the movable guide 64.

[0024] Both first movable guides 63 are disposed between the lock gear 61 and the guide protrusion 31 in a state in which one side surface (hereinafter also referred to as side surface 63a) formed in a substantially flat shape is in surface contact with the gear side surface 61d, and the other side surface (hereinafter also referred to as convex side surface 63b) formed in a convex curve is in R contact (contact between a convex curved surface and a concave curved surface) with the first guide surface 31a. The convex side surface 63b is formed so that its curvature is about R16, which is smaller than the curvature of the first guide surface 31a (about R100 in this embodiment). The first movable guide 63 is formed with an engagement hole 63c for engaging one end of the spring member 82, and a protrusion 63d extending from a position inside the engagement hole 63c to the other axial side is formed.

[0025] Both second movable guides 64 are disposed between the lock gear 61 and the guide protrusion 32 in a state in which one side surface (hereinafter also referred to as side surface 64a) formed in a substantially flat shape is in surface contact with the gear side surface 61e, and the other side surface (hereinafter also referred to as convex side surface 64b) formed in a convex curve is in R contact with the second guide surface 32a. The convex side surface 64b is formed so that its curvature is about R16, which is smaller than the curvature of the second guide surface 32a (about R100 in this embodiment). The second movable guide 64 is formed with an engagement hole 64c for engaging the other end of the spring member 82, and a protrusion 64d extending from a position inside the engagement hole 64c to the other axial side is formed.

[0026] In this embodiment, the first movable guide 63 is formed relative to the second movable guide 64 such that the radial length of the side surface 63a (the vertical length in FIG. 4) is longer than the radial length of the side surface 64a.

[0027] 5, one end and the other end of the spring member 82 are engaged with the engagement hole 63c of the first movable guide 63 and the engagement hole 64c of the second movable guide 64, and the first movable guide 63 and the second movable guide 64 are urged inwardly of the base plate 30 by the spring member 82. With this urging, the first movable guides 63 are pressed against the first guide surface 31a with the convex side surface 63b in surface contact with the gear side surface 61d at the side surface 63a, and the second movable guides 64 are pressed against the second guide surface 32a with the convex side surface 64b in surface contact with the gear side surface 61e at the side surface 64a. Therefore, the first movable guides 63 are always wedged between the lock gear 61 and the guide protrusion 31, and the second movable guides 64 are always wedged between the lock gear 61 and the guide protrusion 32. This eliminates gaps between the members and eliminates rattling in the front-rear direction of the seat back 12. The spring member 82 can be an example of the "biasing member".

[0028] For this reason, both lock gears 61 are guided by the first movable guide 63 and the second movable guide 64, which are biased as described above, so that the gear side surfaces 61d and 61e come into face contact with the side surface 63a of the first movable guide 63 and the side surface 64a of the second movable guide 64, respectively, and are supported so as to be able to slide in the radial direction.

[0029] A plate-shaped cam 70 having a through hole 71 for inserting the shaft portion of the center shaft 22 is rotatably disposed on the base plate 30. The cam 70 is formed so that cam surfaces 72 abut against the inner end faces 61f of both lock gears 61 from the radially inner side, respectively, and causes the external teeth 61a of the lock gears 61 to mesh with the internal teeth 41 of the gear plate 40 when the cam 70 rotates to a predetermined state about the shaft portions serving as the rotation shafts. The cam 70 also has two protrusions 73 formed on one axial side surface with which the other end side of the spring member 81 in the recess 36 engages, and two protrusions 74 formed on the other axial side surface with which the cam lever 90 engages.

[0030] 4, the cam 70 is strongly biased in the lock rotation direction (clockwise in FIGS. 4 and 5) by engaging the other end side of the spring member 81 at the protrusion 73. As a result, the cam 70 abuts against the inner end faces 61f of both lock gears 61 at the cam surface 72, and the biasing force of both spring members 81 in the lock rotation direction strongly biases both lock gears 61 radially outward.

[0031] The shaft portion of the center shaft 22 is inserted into the through hole 71 of the cam 70, and by rotating this center shaft 22, the cam 70 can be rotated in the unlock rotation direction (counterclockwise in Figures 4 and 5) against the biasing force of both spring members 81.

[0032] As shown in FIG. 5, the cam lever 90 is provided with a through hole 91 that fits onto both projections 74 of the cam 70, a pair of cam holes 92, a pair of cam holes 93, and a pair of cam surfaces 94. The cam hole 92 is formed to move the lock gear 61 inward in the radial direction when unlocked by utilizing the inserted projection 61b. The cam hole 93 is formed so that the other end side of the spring member 82 that engages with the engagement hole 64c of the second movable guide 64 and the projection 64d are inserted therethrough, and the inserted projection 64d is used to restrict the radially inward movement of the second movable guide 64 when unlocked. The cam surface 94 is formed so as to restrict the radially inward movement of the first movable guide 63 when unlocked by utilizing the projection 63d.

[0033] The cam lever 90 is attached to the cam 70 with the through holes 91 and the protrusions 74 fitted into each other, the protrusion 61b inserted into each of the cam holes 92, and the protrusion 64d inserted into each of the cam holes 93.

[0034] As a result, when the cam lever 90 rotates together with the cam 70 in the unlock rotation direction, the inner peripheral edges of the cam holes 92 come into contact with the protrusions 61b of the lock gears 61. When the cam lever 90 rotates further in the unlock rotation direction, both protrusions 61b are urged radially inward by the inner peripheral edges of the cam holes 92, causing each lock gear 61 to move radially inward in unison.

[0035] The reclining device 20 thus constructed has both lock gears 61, movable guides 63, 64, cam 70, etc. disposed within cavity C and assembled into a single unit, and the base plate 30 and gear plate 40 are integrated by ring crimping the side periphery of the base plate 30 and gear plate 40 with the cover bracket 50. This allows the base plate 30 and the gear plate 40 to be held so as to be rotatable relative to each other, while restricting relative movement in the axial direction.

[0036] 2 is completed by assembling the reclining operation lever 23 to the center shaft 22, the shaft portion of which is inserted into the through hole 71 of the cam 70. In the reclining device 20 configured in this manner, the seat cushion 11 and the seat back 12 are connected by the reclining device 20 so as to be able to tilt relative to each other by engaging each protrusion 30b of the base plate 30 with the engaging hole of the lower bracket 11a and by engaging each protrusion 40a of the gear plate 40 with the engaging hole of the upper bracket 12a.

[0037] Next, the unlocked and locked states of the reclining device 20 according to this embodiment configured as described above will be described below.

[0038] (Unlocked) First, the unlocked state of the reclining device 20 will be described. When an occupant unlocks the seat back 12 to adjust the inclination angle of the seat back 12, the occupant operates the reclining operation lever 23 to rotate the center shaft 22 in the unlock rotation direction. Then, the cam 70 rotates in the unlock rotation direction together with the center shaft 22 against the biasing forces of both spring members 81.

[0039] By rotating the cam 70 in the unlock rotation direction, the cam surface 72 of the cam 70 is released from contact with the inner end faces 61f of both lock gears 61, and the biasing force of the cam 70 biasing both lock gears 61 radially outward is released. This allows both lock gears 61 to move radially inward, and the meshing between the internal teeth 41 of the gear plate 40 and the external teeth 61a of both lock gears 61 can be released.

[0040] Then, as the cam lever 90 rotates in the unlock rotation direction together with the cam 70, the inner edges of both cam holes 92 of the cam lever 90 come into contact with the protrusions 61b of both lock gears 61, actively moving both lock gears 61 radially inward and releasing the engagement between the internal teeth 41 and the external teeth 61a.

[0041] As described above, when the meshing between the internal teeth 41 and the external teeth 61a is released, the gear plate 40 becomes free to rotate, and the round reclining unit 21 becomes unlocked. When the round reclining unit 21 becomes unlocked, the reclining device 20 becomes unlocked, and when the seat back 12 is tilted backward, the tilt angle of the seat back 12 becomes freely adjustable (see angle A in FIG. 1).

[0042] (Unlocked state) Next, the unlocked state of the reclining device 20 will be described. In the above-described unlocked state, when the seat back 12 is tilted forward, the base plate 30 and the gear plate 40 rotate relative to each other, and both lock gears 61 move to a position where the protrusion 61c can abut against the arc-shaped step portion of the gear plate 40. In this state, when the reclining operation lever 23 is loosened, the cam 70 rotates in the lock rotation direction due to the biasing force of both spring members 81, and the rotation of the cam 70 biases both lock gears 61 radially outward.

[0043] At this time, the projections 61c of both lock gears 61 abut against the arc-shaped stepped portions of the gear plate 40, so that the meshing between the internal teeth 41 and the external teeth 61a is maintained released. Therefore, while the projections 61c abut against the arc-shaped stepped portions of the gear plate 40, even if the seat back 12 is tilted forward so that the base plate 30 and the gear plate 40 rotate relatively, the unlocked state is maintained (see angle B in FIG. 1).

[0044] (Locked) Next, the locked state of the reclining device 20 will be described. When the occupant has finished adjusting the reclining angle of the seat back 12, the reclining operation lever 23 is loosened, and the cam 70 is rotated in the lock rotation direction by the biasing forces of both spring members 81.

[0045] The cam surfaces 72 of the rotating cam 70 come into contact with the inner end faces 61f of both lock gears 61, thereby biasing both lock gears 61 radially outward. As a result, the external teeth 61a of both lock gears 61 move radially outward so as to mesh with the internal teeth 41 of the gear plate 40. Then, as the external teeth 61a of both lock gears 61 mesh with the internal teeth 41 of the gear plate 40, the rotation of the gear plate 40 is restricted, and the reclining device 20 enters a locked state.

[0046] Next, the effect of improving the meshing state by the first movable guide 63 and the second movable guide 64 and the first guide surface 31a and the second guide surface 32a will be described with reference to the drawings. In the conventional configuration in which the lock gear is provided so as to be movable only in the radial direction relative to a guide surface provided on the base plate, if the relative angle between the gear plate and the lock gear deviates from a complete meshing state (a meshing state in which the external teeth of the lock gear moved in the locking direction and the internal teeth of the gear plate mesh completely without any misalignment) due to twisting of the seat frame, the external teeth of the lock gear moved in the locking direction along the guide surface will mesh with the internal teeth of the gear plate in an incomplete meshing state.

[0047] For example, as shown in Fig. 6(A), if the gear plate 40 is deviated by a certain angle (e.g., 0.5°) from the above-mentioned complete meshing state at a certain gear tooth pitch (e.g., 2° / tooth pitch), unless the lock gear 61 tilts, the external teeth 61a of the lock gear 61 and the internal teeth 41 of the gear plate 40 will not mesh sufficiently, resulting in insufficient meshing, as shown in Fig. 6(B). When such insufficient meshing occurs, not only will the meshing portion and the like be insufficient in strength, but it may also promote frame twisting and the like.

[0048] For this reason, in the reclining device 20 according to this embodiment, a first movable guide 63 is disposed between the gear side surface 61d of the lock gear 61 and the first guide surface 31a provided on the base plate 30, and a second movable guide 64 is disposed between the gear side surface 61e and the second guide surface 32a. The first guide surface 31a is formed to be curved concavely so that the distance to the gear side surface 61d decreases as it moves radially inward, and the second guide surface 32a is formed to be curved concavely so that the distance to the gear side surface 61e decreases as it moves radially inward. In addition, the first movable guide 63 is formed so that its side surface 63a, which is pressed against the gear side surface 61d, is in face contact with the gear side surface 61d and its convex side surface 63b, which is pressed against the first guide surface 31a, is convexly curved, and the second movable guide 64 is formed so that its side surface 64a, which is pressed against the gear side surface 61e, is in face contact with the gear side surface 61e and its convex side surface 64b, which is pressed against the second guide surface 32a, is convexly curved.

[0049] In particular, the concave curved shapes of the first guide surface 31a and the second guide surface 32a and the convex curved shapes of the convex side surface 63b and the convex side surface 64b are set so that the force acting on the first movable guide 63 via the first guide surface 31a and the gear side surface 61d by the biasing force of the spring member 82 engaging with the engagement hole 63c is approximately equal to the force acting on the second movable guide 64 via the second guide surface 32a and the gear side surface 61e by the biasing force of the spring member 82 engaging with the engagement hole 64c.

[0050] As a result, when the external teeth 61a of the lock gear 61, which has moved radially outward due to a force in the locking direction from the cam 70, meshes with the internal teeth 41 of the gear plate 40, the first movable guide 63 and the second movable guide 64 are guided by the first guide surface 31a and the second guide surface 32a of the base plate 30 at the convex side surfaces 63b and 64b.

[0051] When the gear plate 40 and the lock gear 61 are engaged in a state where the relative angle between them is shifted from the fully engaged state (see FIG. 6B), the contact position between the convex side surface 63b of the first movable guide 63 and the first guide surface 31a and the contact position between the convex side surface 64b of the second movable guide 64 and the second guide surface 32a are shifted along the curved shapes by the force in the locking direction. As a result, as illustrated in FIGS. 7A and 7B, the first movable guide 63, the second movable guide 64, and the lock gear 61 are inclined with respect to the gear plate 40 so as to eliminate the shift from the fully engaged state. That is, even if the relative angle between the gear plate 40 and the lock gear 61 is shifted, the lock gear 61 is inclined so as to achieve the fully engaged state, so that the external teeth 61a of the lock gear 61 and the internal teeth 41 of the gear plate 40 can be appropriately engaged.

[0052] In particular, in this embodiment, the movable guides 63, 64 and the guide surfaces 31a, 32a are provided in a pair on the left and right sides of the lock gear 61, and therefore the angle at which the movable guides 63, 64 and the lock gear 61 are inclined is large, so that the external teeth 61a of the lock gear 61 and the internal teeth 41 of the gear plate 40 can be more reliably engaged with each other.

[0053] [Other embodiments] The present invention is not limited to the above-described embodiment, and may be embodied as follows, for example. (1) The present invention is not limited to being applied to a reclining device 20 in which a pair of movable guides 63, 64 and concave guide surfaces 31a, 32a are provided on the left and right sides for one locking gear 61, but may also be applied to a reclining device in which a set of movable guides and concave guide surfaces are provided on either the left or right side for one locking gear.

[0054] (2) The present invention is not limited to being applied to reclining device 20 in which a pair of lock gears 61 are employed, and may be applied to reclining devices in which three or more lock gears are employed.

[0055] (3) The present invention is not limited to being applied to the reclining device 20 in which the base plate 30 is attached to the lower bracket 11a and the gear plate 40 is attached to the upper bracket 12a, but may also be applied to a reclining device in which the base plate is attached to the upper bracket 12a and the gear plate is attached to the lower bracket 11a. In this configuration, the upper bracket 12a and the seat back 12 may correspond to the "first member," and the lower bracket 11a and the seat cushion 11 may correspond to the "second member." [Explanation of symbols]

[0056] 10...Vehicle seat 11...Seat cushion (first member) 11a...Lower bracket (first member) 12...Seat back (second member) 12a...Upper bracket (second member) 20...Reclining device 30…Base plate 31a…First guide surface (guide surface) 32a…Second guide surface (guide surface) 40…Gear plate 41…Inner teeth 61…Lock gear 61a…external teeth 61d, 61e…Gear side 63...First movable guide (movable guide) 63a...Side (one side) 63b...Convex side (other side) 64…Second movable guide (movable guide) 64a...Side (one side) 64b...Convex side (other side) 70…Cam 81...Spring member 82...Spring member (biasing member) 90…Cam lever

Claims

1. A reclining device that adjusts a tilt angle between a first member and a second member that tilt relatively, comprising: A base plate attached to the first member; a gear plate attached to the second member and assembled to be rotatable relative to the base plate, the gear plate having internal teeth; a lock gear that is assembled to the base plate so as to be slidable in a radial direction and has external teeth that can mesh with the internal teeth; a movable guide disposed between a gear side surface of the lock gear along a sliding direction and a guide surface provided on the base plate; A cam capable of controlling radial movement of the lock gear and biased in a locking direction to cause the external teeth to mesh with the internal teeth; a biasing member that biases the movable guide in a direction to press the movable guide against both the gear side surface and the guide surface; Equipped with The guide surface is formed to be concavely curved so that the distance between the guide surface and the gear side surface becomes closer toward the inside in the radial direction, The reclining device is characterized in that the movable guide is formed so that one side surface that is pressed against the gear side surface is in surface contact with the gear side surface, and the other side surface that is pressed against the guide surface is convexly curved.

2. The reclining device according to claim 1, wherein the movable guide and the guide surface are provided in a pair on the left and right sides of the lock gear.

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