Reclining device for a vehicle seat

Abstract

A reclining device includes a base plate, a tooth plate rotatable and including a first recess, a second recess in a ring shape, and internal teeth formed in an inner circumferential surface of the first recess, three locking members including external teeth configured to engage with the internal teeth, and a cam configured to move the locking members. Each of the locking members includes a first protrusion. The second recess includes a first restriction configured to contact the first protrusion in a radial direction and restrict movement of the locking members in an engagement direction. At least one of the locking members includes a second protrusion. The tooth plate includes a second restriction configured to contact the second protrusion at a position radially inward of a position at which the first protrusion contacts the first restriction.

Description

Technical Field

[0001] This invention relates to an improvement in reclining mechanisms for vehicle seats. Background Technology

[0002] It is known that the reclining mechanism used in vehicle seats, which have a seat cushion as a seat and a seat back as a backrest, is designed to have a reclining range that allows for step-by-step adjustment of the seat back's recline posture and locks that posture, as well as a so-called free range where the seat back is not locked. In a representative design, the reclining range is from a roughly upright position of the seat back to the maximum recline posture (i.e., the so-called fully flat position), and the free range is from an upright position of the seat back to the maximum forward recline posture. The sum of the reclining range and the free range (i.e., the range from the maximum forward recline posture to the maximum recline posture) is sometimes set to approximately 180 degrees.

[0003] In addition, there are various proposals for a reclining device that includes a disc-shaped unit as a joint or hinge connecting the seat cushion and the seat back and is used for adjusting the posture of the seat back.

[0004] For example, Patent Document 1 discloses a reclining device comprising a base member, a toothed member, and three locking members housed inside the base member and the toothed member. The reclining device is configured such that, within the reclining range (i.e., the locking range), the outer teeth of the three locking members engage / disengage forward relative to the inner teeth of the toothed member, thereby allowing for changes in the posture of the seat back and locking the seat back; and within the free range, the movement (or position) of the locking members is restricted and they remain unlocked to prevent the outer teeth of the locking members from engaging with the inner teeth of the toothed member, thereby ensuring a free state.

[0005] Therefore, the tilting device is usually configured to include three or four locking members in order to increase the locking strength by increasing the number of locking members.

[0006] In the case of employing three or more locking members, to ensure sufficient range of motion, Patent Document 1 discloses forming a protrusion (51) in only one of the locking members and a protrusion (27) opposite to the protrusion in the toothed member (i.e., the upper arm). The protrusion and protrusion are configured to contact each other, preventing the outer teeth of the one locking member from engaging with the inner teeth of the toothed member and holding the one locking member in an inward position. In this case, the cam stops rotating when the locking side cam surface of the cam has pushed the one locking member out to the locking direction. Therefore, the other two locking members without protrusions are also in a position preventing engagement of the outer teeth (i.e., preventing the outer teeth from moving radially outward).

[0007] However, a clearance exists in the rotational direction of the cam between the position where the locking side cam surface contacts the locking member and the position where the releasing side cam surface contacts the locking member. Therefore, compared to the locking member with the protrusion, the other two locking members without protrusions are allowed to move beyond the width of the clearance in the radially outward direction (i.e., the direction for meshing with the internal teeth). This may cause the other two locking members to move unexpectedly in the radially outward direction due to vehicle inertia, vibration, etc., resulting in noise caused by the contact between the tips of the internal teeth and the external teeth.

[0008] In view of this, the invention of Patent Document 1 is configured to position two additional locking members without protrusions above the center of rotation of the tilting device, and to use gravity to prevent the outer teeth from moving in the direction of meshing with the inner teeth.

[0009] However, this countermeasure keeps the other two locking members in a position away from the internal teeth, and may not be able to lock at the initial locking position (i.e., the upright position) of the initial locking position within the locking range of the seat back when returning from the free range to the locking range, and suffers from so-called tooth skipping.

[0010] Furthermore, when the cam is operated by the lever in the locking release direction, thereby moving the locking member radially inward away from the internal teeth, a protrusion of one locking member may collide with the side surface of the protrusion of the toothed member. In this structure where a protrusion is formed in only one locking member, especially in the case of vehicle seats with a large seat back weight and a large biasing force that causes the seat back to tilt forward, the side surfaces of the protrusion of one locking member and the protrusion of the toothed member may deform due to the collision between them.

[0011] In view of this, Patent Document 2 discloses an invention configured such that the protrusion of one locking member faces the first guide throughout its free range, while the protrusions of other locking members face the second guide in a portion of the free range adjacent to the locking range. This helps to distribute the collision load even in the event that the protrusion of the locking member collides with the side surface of the guide due to insufficient radial inward movement of the locking member, thereby suppressing deformation of the protrusion of the locking member and the side surface of the guide due to the collision between them.

[0012] Reference List

[0013] Patent documents

[0014] PTL 1: JP 2003-009978 A

[0015] PTL 2: JP 2018-023583 A Summary of the Invention

[0016] Technical issues

[0017] However, even the invention of Patent Document 2 may experience problems within the free range where the protrusion does not face the second guide, namely, that the other locking members move in the radially outward direction (i.e., the locking direction). Therefore, similar to the invention of Patent Document 1, due to the movement of the locking members in the locking direction, the other locking members have to be arranged away from the inner teeth. This leads to a technical problem similar to that of the invention of Patent Document 1, namely, that the failure to lock at the initial locking position (i.e., the upright position) which is the initial locking position within the locking range results in so-called tooth skipping between the inner and outer teeth.

[0018] In addition, the technology in Patent Document 2 has another technical problem: at the initial locking position, the protrusions of the first and second locking members are separated from the guide portion and the timing of the engagement of the external teeth and the internal teeth is unstable. This is because the protrusions of the first and second locking members are in different radial positions.

[0019] In view of the aforementioned technical problems of conventional reclining devices, it is desirable to provide a reclining device for a vehicle seat, which is configured to: prevent noise caused by contact between the inner teeth of the toothed member and the outer teeth of the locking member; stabilize the timing of engagement between the inner and outer teeth; reduce the occurrence of tooth skipping at the initial locking position when the seat back returns from the free range to the locking range; and prevent the protrusion of the locking member and the limiting part of the toothed member from colliding with each other in the circumferential direction and thereby deforming.

[0020] Solution

[0021] According to one aspect of the invention, a reclining device for a vehicle seat is provided, the reclining device comprising: a base member fixed to a first of a lower support of a seat cushion and an upper support of a seat back; a toothed member fixed to a second of the lower and upper supports, arranged to overlap with the base member and configured to rotate relative to the base member; a first recess shaped as a circle, formed inside the outer periphery of the toothed member and centered on the rotation center of the toothed member; an inner tooth formed on the inner circumferential surface of the first recess; a plurality of locking members arranged between the base member and the toothed member and configured circumferentially, wherein each locking member includes an outer tooth that is radially movable to engage with the inner tooth in a locked position and release the engagement in an unlocked position; a cam arranged radially inside the locking members and configured to move the locking members between a locked position and an unlocked position; and a biasing member biasing the locking members via the cam along a locking direction that is the direction of engagement of the inner and outer teeth. The toothed member includes a second recess, which is annularly shaped and formed radially inside the first recess, centered on the rotation center of the toothed member. Each locking member includes a first protrusion projecting toward the second recess and configured to radially face the outer inner circumferential surface of the second recess. The second recess includes a plurality of first allowable portions and a plurality of first restrictive portions. The first allowable portions are configured to face the first protrusions with a gap, respectively, within a locking range on the reclining side from an initial locking position of the seat back relative to the seat cushion, and allow the locking members to move to the locking position. The first restrictive portions are configured to be positioned radially inside the first allowable portions within a first angular range on the forward reclining side from the initial locking position of the seat back relative to the seat cushion, and respectively contact the first protrusions radially and restrict movement of the first protrusions in the engagement direction. At least one locking member includes a second protrusion positioned radially inside the first protrusion and projecting toward the inner side of the second recess. The toothed member includes a second restrictive portion. The second limiting part is configured to be further set within a second angle range on the forward tilt side from a position that at least partially overlaps with the initial locking position of the seat back on the forward tilt side, and to contact the second protrusion of one of the locking members at a position radially inward relative to the position where the first protrusion contacts the first limiting part.

[0022] Beneficial effects of the invention

[0023] The invention claimed in technical solution 1 of this application is used to: prevent noise caused by the contact between the inner teeth of the toothed member and the outer teeth of the locking member; stabilize the timing of the meshing between the inner and outer teeth; reduce tooth skipping at the initial locking position when the seat back returns from the free range to the locking range; and prevent the protrusion of the locking member and the limiting part of the toothed member from colliding with each other in the circumferential direction and thereby deforming. Attached Figure Description

[0024] Figure 1 This is a side view of a vehicle seat reclining device according to a first embodiment of the present invention.

[0025] Figure 2 yes Figure 1 The diagram shown is an exploded view of only the reclining portion of a vehicle seat reclining device.

[0026] Figure 3 (A) is a front view showing how the base plate and the helical spring are arranged. Figure 3 (B) is along Figure 3 A sectional view of line AA in (A).

[0027] Figure 4 (A) is a front view showing how the base plate, helical spring, locking member and cam are arranged. Figure 4 (B) is along Figure 4 A sectional view of line BB in (A).

[0028] Figure 5 When viewed from the inside Figure 2 A perspective view of the toothed plate.

[0029] Figure 6 When viewed from the inside Figure 2 The front view of the toothed plate.

[0030] Figure 7 (A) is a perspective view of the toothed plate side. Figure 2 A perspective view showing how the various components are arranged. Figure 7 (B) is along Figure 7 A sectional view of line CC in (A).

[0031] Figure 8 When viewed from the side perspective of the toothed plate, the rearward tilt is in Figure 1 The diagram illustrates the operation in the initial locked position state.

[0032] Figure 9 This is an operational illustration diagram that unfolds to show the relationship between the first limiting part and the first allowing part of the toothed plate and each of the first protrusions, as well as the correspondence between the second limiting part and the second allowing part and each of the second protrusions.

[0033] Figure 10 This is an instructional diagram showing the operation of the seat back when viewed from the side of the toothed plate within its free range, after it has been moved from the locked range to the first angle range.

[0034] Figure 11This is an instruction diagram showing the operation at the maximum forward tilt position on the second angle side of the first angle range when viewed from the toothed side within the free range of the seat back.

[0035] Figure 12 This is a front view showing how the components of the tilting device according to a second embodiment of the present invention are arranged.

[0036] Figure 13 This is an operational illustration diagram that unfolds to show the relationship between the first limiting portion and the first allowing portion of the toothed plate according to the second embodiment and each of the first protrusions, as well as the correspondence between the second limiting portion and the second allowing portion and the second protrusions.

[0037] Figure 14 This is a cross-sectional view of the tilting device according to a third embodiment of the present invention.

[0038] Figure 15 This is a cross-sectional view of the tilting device according to the fourth embodiment of the present invention. Detailed Implementation

[0039] The following describes an embodiment of a reclining device for a vehicle seat according to the present invention.

[0040] Figure 1 The accompanying drawings and following figures specifically illustrate embodiments of a reclining device for a vehicle seat according to the present invention. In particular, Figure 1 This is a schematic side view of the entire device. Figure 2 This is a squinting exploded view of the backward tilting section 5.

[0041] like Figure 1 As shown, the reclining device 1 includes a vehicle seat 2 consisting of a seat cushion 3 and a seat back 4, and includes a reclining portion 5 as the main part for adjusting the posture of the seat back 4, which is configured to be upright and reclined. The reclining portion 5 has a flat disc shape, is disposed at the joint of the seat cushion 3 and the seat back 4, and functions as a joint or hinge to perform the reclining function.

[0042] In detail, such as Figure 1 As shown, the reclining portion 5 is pre-formed as a single unit and is located at the junction of the lower support 6 and the upper support 7. The lower support 6 is fixed to a seat cushion frame (not shown) (which is the frame of the seat cushion 3). The upper support 7 is fixed to a seat back frame (not shown) (which is the frame of the seat back 4). An operating lever 8 protrudes from the reclining portion 5. The operating lever 8 is an operating member for reclining operation. Furthermore, the seat back 4 always receives a biasing force in the forward tilting direction applied by a spring (not shown).

[0043] like Figure 1As clearly shown, the initial locking position P1 is the standard posture position of the reclined seat back 4, that is, the reference position in the design of the seat back 4. The upright position P2 is the position where the seat back 4 is slightly tilted forward and substantially upright relative to the initial locking position P1. In this case, as described above, the recline posture position of the seat back 4 can be arbitrarily adjusted and locked within the range from the initial locking position P1 to the maximum reclined position P3 of the seat back 4 (i.e., the so-called fully flat position). This range is the locking range (or locking area) R1. The first angular range R2 is the angular range from the initial locking position P1 to the upright position P2. The second angular range R3 is the angular range from the initial locking position P1 to the maximum forward reclined position P4 of the seat back 4, which includes the first angular range R2. In the second angular range R3 from the initial locking position P1, the seat back 4 is not locked but in an unlocked state and can be freely tilted forward and backward (i.e., freely rotated). Therefore, the second angular range R3 corresponds to the free range. When the seat back 4 is tilted back from the second angle range R3, the seat back 4 is locked and its posture is restrained for the first time at the initial locking position P1.

[0044] like Figure 2 As shown, the rear tilting part 5 includes a base plate 9, a toothed plate 10, a retaining ring 11, three locking members 12A, 12B, and 12C, a cam 14, and three helical springs 13. The base plate 9 is a base member with a shallow disc shape. The toothed plate 10 is a toothed member with a shallow disc shape and is arranged to face and overlap the base plate 9. The retaining ring 11 constrains and holds the base plate 9 and the toothed plate 10, allowing them to rotate relative to each other. Each of the three locking members 12A, 12B, and 12C has a sector gear shape and is arranged between the base plate 9 and the toothed plate 10. The cam 14 has a triangular shape and is arranged on the inner circumferential side relative to the three locking members 12A, 12B, and 12C. The three helical springs 13 are biasing members that bias the cam 14 in a direction that causes the cam 14 to press the three locking members 12A, 12B, and 12C outward. Furthermore, as described below, the cam 14 is connected to... Figure 1 On the rotation axis 8a of the operating lever 8 shown.

[0045] Figure 3 (A) and Figure 3 (B) are the front view and sectional view showing how the substrate 9 and the helical spring 13 are arranged.

[0046] The substrate 9 is formed by stamping a uniformly thick disc-shaped material into a shallow dish shape along its thickness direction using a method such as high-precision stamping. The substrate 9 includes an inner bottom surface that includes spring-receiving recesses 15. The spring-receiving recesses 15 are recessed to a lower level and formed in a trisected position in the circumferential direction. Each spring-receiving recess 15 includes a spring-receiving protrusion 16 formed by a so-called half-stamping at its approximately center. Thus, each spring-receiving recess 15 receives one of the helical springs 13 such that the inner circumferential end 13a of one of the helical springs 13 is locked onto the spring-receiving protrusion 16.

[0047] The inner bottom surface of the substrate 9 also includes a shaft 17 and a guide embossed portion 18 to avoid obstructing the spring receiving recess 15. The shaft 17 is arranged at three circumferentially divided positions, while the guide embossed portion 18 is arranged at another three circumferentially divided positions, different from the phase of the shaft 17. The shaft 17 and the guide embossed portion 18 protrude in the opposite direction to the spring receiving recess 15. The shaft 17 pivotally supports the locking members 12A to 12C, respectively. The guide embossed portion 18 guides the pivoting of the locking members 12A to 12C, respectively.

[0048] Figure 4 (A) and Figure 4 (B) is a front view and a sectional view showing how the base plate 9 accommodates the helical spring 13, the locking members 12A to 12C and the cam 14.

[0049] Three locking members 12A to 12C are housed in the same circumferential position as the coil spring 13 housed in the spring receiving recess 15, so as to partially overlap with the coil spring 13. Each of the locking members 12A to 12C includes a receiving recess 19 formed by cutting, and uses the receiving recess 19 as a bearing to engage with the corresponding one of the shafts 17. In addition, each of the guide embossed portions 18 guides the outer periphery of the corresponding one of the locking members 12A to 12C around the corresponding one of the shafts 17. These configurations allow the locking members 12A to 12C, arranged in circumferentially trisected positions, to swing. This allows the external teeth 20 of the locking members 12A to 12C to be oscillatingly supported radially on the base plate 9, with the center of the swing being the shaft 17. The shaft 17 and the receiving recess 19 (which are configured to engage each other) both include two ends located circumferentially on the base plate 9, both ends having cylindrical surfaces to allow relative rotation, thereby realizing the function of the shaft 17 and the receiving recess 19.

[0050] Each of the locking members 12A to 12C has a so-called fan-shaped shape, which has an inner arc surface (i.e., receiving recess 19) and an outer arc surface. The fan includes a first side surface containing the outer teeth 20. Furthermore, the locking members 12A to 12C each include first protrusions 21a to 21c formed by so-called half-punching. Specifically, locking member 12A includes a first protrusion 21a, locking member 12B includes a first protrusion 21b, and locking member 12C includes a first protrusion 21c. Each of the first protrusions 21a to 21c protrudes from the surface of the fan facing the toothed plate 10 near the first side surface of the fan. In the circumferential direction about the rotation center of the toothed plate 10, each of the first protrusions 21a to 21c is located centrally relative to the outer teeth 20. In the radial direction, each of the first protrusions 21a to 21c is located inwardly relative to the outer teeth 20.

[0051] Two of the three locking members 12A to 12C, 12A and 12B, respectively include second protrusions 22a and 22b formed by half-punching. Each of the second protrusions 22a and 22b is configured to have a rectangular cross-section, protrudes in the same direction as the first protrusions 21a and 21b, and is located near a fan-shaped second side opposite to the outer tooth 20. In other words, each of the second protrusions 22a and 22b is positioned opposite to the corresponding one of the first protrusions 21a and 21b, traversing the receiving recess 19. Radially, when viewed from the center of rotation of the toothed plate 10, each of the second protrusions 22a and 22b is located inside the corresponding one of the first protrusions 21a and 21b.

[0052] like Figure 2 and Figure 4 As shown, cam 14 is arranged at the center of the arrangement of the three locking members 12A to 12C so as to face the fan-shaped outer arc surface of the three locking members 12A to 12C. Each of the locking members 12A to 12C includes a cam surface 23 (including a locked cam surface 23a and a released cam surface 23b) in the fan-shaped outer arc surface. Each of the cam surfaces 23 has a predetermined profile with a recess at the middle of the fan-shaped outer arc surface and is used as the driven side. Cam 14 includes cam surfaces 24 at three vertices. Each of the cam surfaces 24 has a predetermined profile that engages with the corresponding one of the cam surfaces 23, including a locking cam surface 24a and a released cam surface 24b, and is used as the driving side.

[0053] Therefore, the recess of the cam surface 23, which is the driven side of the locking members 12A to 12C, receives the cam surface 24, which is the driving side of the cam 14.

[0054] The cam 14 includes an inner tooth 14a at its center, while the rotation axis 8a of the operating lever 8 includes an outer tooth 8b. These inner and outer teeth are connected to each other, thereby rotatably connecting the operating lever 8 to the cam 14 integrally.

[0055] The cam 14 also includes spring-receiving protrusions 14b at three points on the inner side adjacent to the cam surface 24. The spring-receiving protrusions 14b are formed by a so-called half-blanking and protrude toward the base plate 9. Each of the outer peripheral ends 13b of the helical spring 13 then locks onto the corresponding one of the spring-receiving protrusions 14b of the cam 14. This allows the helical spring 13 to... Figure 4 A spring force is applied to the cam 14 in the clockwise direction, and ultimately causes the cam 14 to be radially outward biased against the outer teeth 20 of the locking members 12A to 12C.

[0056] like Figure 4 As shown, each adjacent pair of guide embossed portions 18, 18, and 18 clamps the corresponding one of the locking members 12A to 12C between them. Each of the locking members 12A to 12C is pivotally supported from both sides via a fan-shaped outer arcuate surface by the arcuate guide surfaces 18a and 18b of the guide embossed portion 18. Thus, the locking members 12A to 12C, configured to pivot about the axis 17 as a fulcrum, are also guided by the guide embossed portion 18 via their outer periphery. This allows the locking members 12A to 12C to move smoothly.

[0057] Figure 5 Viewed from the inside Figure 2 A perspective view of the toothed plate. Figure 6 Viewed from the inside Figure 2 The front view of the toothed plate.

[0058] Similar to substrate 9, toothed plate 10 is molded into a shallow dish shape by pressing a disk-shaped material of uniform thickness in the thickness direction, and includes a first recess 26. Figure 5 and Figure 6 As shown, the first recess 26 includes an inner circumferential wall surface that contains the internal teeth 25 throughout its entire circumference. The toothed plate 10 also includes a second recess 27, which is formed in the inner bottom surface of the toothed plate 10 adjacent to the inner side of the internal teeth 25. The second recess 27 has an annular shape, is at a lower level in the axial direction, and is concentric with the internal teeth 25.

[0059] like Figure 5 and Figure 6As shown, the second recess 27 includes an outer peripheral wall surface 27a, three first allowable portions 28, and three first restrictive portions 29. The outer peripheral wall surface 27a is an outer inner peripheral wall surface formed on the outer peripheral side of the second recess 27 and has an annular shape. The three first allowable portions 28 are formed in the outer peripheral wall surface 27a. The three first restrictive portions 29 are formed in the inner peripheral wall surface of the second recess 27 between the first allowable portions 28, arranged at approximately 120° intervals in the circumferential direction, and protrude radially inward. The three first restrictive portions 29 are radially positioned relative to the rotation center of the toothed plate 10 to face the first protrusions 21a to 21c of the three locking members 12A to 12C, respectively, wherein the three locking members 12A to 12C protrude into the interior of the second recess 27, and the outer surfaces of the three locking members 12A to 12C are allowed to contact the inner surface 29a of the first restrictive portions 29. Within the locking range, the first allowable portion 28 of the second recess 27 is positioned facing the first protrusions 21a to 21c with a gap between them and does not contact them. The second recess 27 also includes three notched recesses 30 in the circumferential direction at approximately the middle of the first allowable portion 28. The three notched recesses 30 extend radially outward. At least one of the three notched recesses 30 is narrower in circumferential width than the other two and is used for circumferential positioning when mounting the toothed plate 10.

[0060] like Figure 5 and Figure 6 As shown, the second recess 27 includes an inner peripheral wall surface 27b that is radially inward relative to the outer peripheral wall surface 27a. The inner peripheral wall surface 27b is the inner-outer peripheral surface of the second recess 27, has an annular shape, and includes two second restricting portions 31 and 32 and a second permissive portion 33. The two second restricting portions 31 and 32 and the second permissive portion 33 are arc-shaped, continuously formed, and differ from each other in outer diameter, wherein the radius of the second restricting portion 32 is larger than the radius of the second restricting portion 31. The two second restricting portions 31 and 32 and the second permissive portion 33 are arranged in series in the circumferential direction, each occupying an angular range of approximately 120°. The second permissive portion 33 is smaller in outer diameter than both the two second restricting portions 31 and 32, such that the second protrusion 22a of the locking member 12A faces the second permissive portion 33 radially with a gap and does not contact the second permissive portion 33.

[0061] Within the locking range R1 of the second protrusion 22a of locking member 12A facing the second allowable portion 33, the second protrusion 22b of locking member 12B is positioned radially across a gap to face the smaller radius second limiting portion 31 and does not contact it. Therefore, the second protrusion 22a of locking member 12A is radially inward compared to the second protrusion 22b of locking member 12B. Additionally, three steps 34, 35, and 36 are formed between the two second limiting portions 31 and 32 and the second allowable portion 33.

[0062] When the seat back 4 is in the first angle range R2, the first protrusions 21a, 21b, and 21c of the three locking members 12A, 12b, and 12C are allowed to ride on the inner surface 29a of the first limiting part 29. This prevents the external teeth 20 of the three locking members 12A, 12b, and 12C from engaging with the internal teeth 25 of the toothed plate 10. When the seat back 4 is in the second angle range R3, the second protrusions 22a and 22b of the two locking members 12A and 12B are allowed to ride on the inner outward peripheral surfaces of the second limiting parts 31 and 32. This prevents the external teeth 20 of the two locking members 12A and 12b from engaging with the internal teeth 25. In this case, the external teeth 20 of the other locking member 12C cannot engage with the internal teeth 25 because the two locking members 12A and 12b stop the rotation of the cam 14, which is already biased in the locking direction.

[0063] Figure 7 (A) is shown when viewed from the tooth plate side. Figure 2 A perspective view showing how the various components are arranged. Figure 7 (B) is along Figure 7 The sectional view of line CC shown in (A).

[0064] like Figure 7 (A) and Figure 7 As shown in (B), when the toothed plate 10 and the base plate 9 face each other, the first protrusions 21a to 21c protruding from the locking members 12A to 12C are received in the second recess 27 of the toothed plate 10. Similarly, the second protrusions 22a and 22b protruding from the two locking members 12A and 12B are also received in the second recess 27.

[0065] from Figure 2 The toothed plate 10 shown begins in a state facing the base plate 9, which includes the helical spring 13, three locking members 12A to 12C, and the cam 14. Figure 2 The retaining ring 11 shown is plastically formed by methods such as roll forming or crimping. This prevents the substrate 9 and the toothed plate 10 from separating from each other in the axial direction, while making the substrate 9 and the toothed plate 10 concentric and rotatably coupled relative to each other.

[0066] Cam 14 receives spring force from helical spring 13 and presses the three locking members 12A to 12C radially outward. This causes the outer teeth 20 of the locking members 12A to 12C to engage with the inner teeth 25 of the toothed plate 10, allowing locking. Thus, the three helical springs 13 act as biasing members that bias the three locking members 12A to 12C in the locking direction to engage the outer teeth 20 with the inner teeth 25.

[0067] like Figure 7As shown in (A), the smaller and larger radii of the second limiting portions 31 and 32 formed in the inner peripheral wall surface 27b of the second recess 27 of the toothed plate 10 have different radii relative to the rotation center of the toothed plate 10. Correspondingly, the second protrusion 22a of the first locking member 12A and the second protrusion 22b of the second locking member 12B are different from each other in radial position. Specifically, the second protrusion 22a of the first locking member 12A has a radial length L from the rotation center P of the toothed plate 10, which is longer than the radial length L1 of the second protrusion 22b of the second locking member 12B from the rotation center P.

[0068] Figure 8 In the backward tilting position Figure 1 The diagram illustrates the operation when viewed from the side of the toothed plate in the initial locked position P1 state.

[0069] The seat back is in position 4. Figure 1 In the initial locked position P1 state, such as Figure 8 As shown, each of the first protrusions 21a to 21c is located within the second recess 27 and positioned adjacent to the circumferential front end of the corresponding one in the first allowable portion 28. In response to the rotational operation of the cam 14 to release the lock, the locking members 12A to 12C move inward to the lock-released position (i.e., the unlocked position), allowing the seat back 4 to rotate to the forward-leaning side. The first protrusions 21a to 21c, already positioned at the first allowable portion 28, are then allowed to... Figure 7 As shown in (A), it rides on the inner surface 29a of the first limiting part 29.

[0070] Furthermore, in the initial locked position P1 state, such as Figure 8 As shown, the second protrusions 22a and 22b are respectively located near the first step 34 between the second limiting portion 31 and the second allowing portion 33 of a smaller radius, and the second step 35 between the second limiting portion 31 of a smaller radius and the second limiting portion 32 of a larger radius. In response to the rotational operation of the cam 14 and its shift to the locked release position, the second protrusions 22a and 22b are allowed to... Figure 7 As shown in (A), cross the first step 34 and the second step 35.

[0071] The above example illustrates the case where the substrate 9 of the tilting portion 5 is welded to the lower support 6 and the toothed plate 10 of the tilting portion 5 is welded to the upper support 7. However, the substrate 9 and the toothed plate 10 can exchange their relative positions with respect to the lower support 6 and the upper support 7.

[0072] <Effect of the vehicle seat reclining device in this embodiment>

[0073] The following is for reference Figure 8 , 9Sections 10 to 12 describe the effects of the rear-leaning section 5 configured as described above. Figure 9 This is an operational illustration diagram that unfolds to show the relationship between the first limiting part and the first allowing part of the toothed plate and each of the first protrusions, as well as the correspondence between the second limiting part and the second allowing part and each of the second protrusions. Figure 10 This is an instruction diagram for the operation of the seat back within its free range, showing the state after shifting from the initial locked position P1 to the position after moving to the first angle range R2. Figure 11 This is an instructional diagram of the seat back within its free range, showing the state after shifting from the second angular range R3 (i.e., the free range) to a position overlapping with the first angular range R2.

[0074] Figure 8 The rear tilting section 5 is shown in the position. Figure 1 The initial locking position P1 shown illustrates that the base plate 9, fixed to the lower support 6, serves as the fixed side, while the toothed plate 10, fixed to the upper support 7, serves as the movable side. The cam surface 24 (i.e., the locking cam surface 24a) on the drive side of the cam 14 contacts the locked cam surface 23a of the cam surfaces 23 of the locking members 12A to 12C, wherein each locked cam surface 23a is located on the side of the external tooth 20 relative to the axis 17, which serves as the pivot point. Each of the first protrusions 21a to 21c faces the outer inward circumferential surface of the second recess 27 of the toothed plate 10 and faces the corresponding one of the first allowable portions 28 with a gap. In this state, each of the first protrusions 21a to 21c faces the first side surface 29c of the first restrictive portion 29 with a small gap in the circumferential direction. Each of the second protrusions 22a and 22b faces the end face of the corresponding one of the first step 34 and the second step 35 in the circumferential direction with a small gap, and faces the corresponding one of the second restrictive part 32 and the second allowable part 33 of a smaller radius in the radial direction with a gap.

[0075] Therefore, each locking member 12A to 12C swings outward radially about the axis 17 which serves as a fulcrum, and is engaged with the toothed plate 10 by the external tooth 20.

[0076] In response to the operation of lever 8, the cam 14 is moved from Figure 8 Rotate the state to the right Figure 10 In state (a), the release cam surface 24b of cam 14 presses against the release cam surface 23b of locking members 12A to 12C. This causes locking members 12A to 12C to swing inward about axis 17, which serves as a fulcrum, and releases the engagement between the external tooth 20 and the internal tooth 25 of toothed plate 10. In this case, if the radial inward retraction of locking members 12A to 12C is less than... Figure 9As shown by the distance h1, the first protrusions 21a to 21c collide with the first side surface 29c of the first limiting portion 29 and stop at the upright position P2 of the seat back 4. The locking members 12A to 12C are configured such that all the first protrusions 21a to 21c collide with the first side surface 29c of the first limiting portion 29 substantially simultaneously. This helps to distribute the impact load and thereby suppresses compressive deformation of the first protrusions 21a to 21c and the first limiting portion 29.

[0077] Furthermore, in this case, such as Figure 9 As shown, locking members 12A and 12B are configured such that the positions of the first step 34 and the second step 35 formed between the second restricting portions 31 and 32 and the second allowing portion 33 are moved by a distance t1 in the direction of rotation toward the second angle range R3 relative to the position of the step formed between the first restricting portion 29 and the first allowing portion 28. This prevents the second protrusions 22a and 22b from colliding with the end faces of the first step 34 and the second step 35 of the second restricting portions 31 and 32.

[0078] In other words, omitting the distance t1 might allow the second protrusions 22a and 22b to collide with the end faces of the first step 34 and the second step 35 due to the dispersion of the distance. This embodiment uses the distance t1 and thus avoids this collision.

[0079] As described above, the locking members 12A to 12C retract radially inward by a greater amount than the distance h1. This allows the seat back 4 to move to a second angular range R3 relative to the initial locking position P1, which is on the forward-leaning side.

[0080] like Figure 9 As shown, when the outer teeth 20 of the locking members 12A to 12C engage with the inner teeth 25, the first protrusions 21a to 21c and the second protrusions 22a and 22b are positioned such that the distance h3 required for the second protrusions 22a and 22b to ride on the outer surfaces of the second limiting portions 31 and 32 is greater than the distance h1 required for the first protrusions 21a to 21c to ride on the inner surface 29a by a distance h2 in the radial inward retraction of the locking members 12A to 12C. Therefore, when the radial inward retraction of the locking members 12A to 12C is greater than the distance h1 but less than the distance h3, the second protrusions 22a and 22b can collide with the end faces of the steps 34 and 35.

[0081] However, steps 34 and 35 are continuous with ramps 37 and 38, respectively, which are configured to allow the second protrusions 22a and 22b to escape (i.e., move) radially inward. This prevents the second protrusions 22a and 22b from colliding with the end faces of steps 34 and 35.

[0082] Each step 34 and 35 of the second limiting portions 31 and 32 includes a corner that is lower by a distance h4 than the distance h1 required to ride onto the first limiting portion 29. This prevents the second protrusions 22a and 22b from colliding with the end faces of the steps 34 and 35 of the second limiting portions 31 and 32. Additionally, in Figure 10 In state (a), such as Figure 10 As shown in (b), each of the second protrusions 22a and 22b faces the corresponding one of the second restrictive portions 31 and 32 in the radial direction with a small gap, and as Figure 10 As shown in (c), each of the first protrusions 21a to 21c contacts the corresponding one in the inner surface 29a of the first limiting portion 29.

[0083] Next, with the seat back 4 in its most forward-leaning position within the locking range R1 that overlaps with the second angle range R3, as follows: Figure 11 As shown in (a) to 11(c), the second protrusions 22a and 22b contact the second restricting portions 31 and 32, respectively, while each of the first protrusions 21a to 21c of the locking members 12A to 12C is positioned radially inward at a distance h2 relative to the corresponding one of the inner surfaces 29a of the first restricting portion 29, and has a gap with the inner surface 29a to avoid contact with it. Figure 10 and Figure 11 In the diagram, each dashed line adjacent to the second restrictive parts 31 and 32 indicates a situation where the second restrictive parts 31 and 32 are formed at the same position as the distance h1, where h1 is the position where the vehicle rides on the first restrictive part 29. Figure 9 In the middle, the distance h3 is the distance by which the second protrusions 22a and 22b are raised by the second limiting parts 31 and 32, which satisfies the relationship h3-h1=h2.

[0084] Although the contact between the second protrusions 22a and 22b and the second limiting portions 31 and 32 prevents the locking members 12A and 12B from swinging radially outward, the cam 14 is still rotated by the biasing force of the coil spring 13 in the direction that pushes the locking members 12A to 12C radially outward. As a result, the rotation of the cam 14 stops when the cam surface 24 (i.e., the locking cam surface 24a) of the cam 14 presses against the locked cam surface 23a of the first locking member 12A and the second locking member 12B. Since the rotation of the cam 14 stops, the third locking member 12C, without the second protrusions 22a and 22b, remains in the locked-released state. The third locking member 12C is allowed to move in the locking direction until its released cam surface 23b contacts the release cam surface 24b of the cam 14. Therefore, due to vibration, acceleration, etc., the third locking member 12C can move in the locking direction to the position where it contacts the release cam surface 24b of the cam 14.

[0085] However, as Figure 9As shown, the third locking member 12C (i.e., the first protrusion 21c) is positioned inward at a distance h2 relative to the position that contacts the inner surface 29a of the first limiting portion 29. This prevents the outer teeth 20 of the third locking member 12C from contacting the inner teeth 25 and generating noise. Furthermore, the above configuration prevents the first protrusion 21c of the third locking member 12C from colliding with the second side 29d of the first limiting portion 29 when tilted backward toward the first angle range R2 in the second angle range R3.

[0086] Therefore, in such Figure 1 When the seat back 4 is tilted back from the free range R3 to the locked range R1 as shown, Figure 11 As shown, the second protrusions 22a and 22b move radially outward along ramps 37 and 38 while contacting the upper surfaces of the second restrictive portions 31 and 32. At the midpoint of the first angular range R2 within the free range R3, as... Figure 9 As shown, the first protrusions 21a to 21c of the locking members 12A to 12C contact the inner surface 29a of the first limiting portion 29. Figure 4 In the diagram, range R4 represents the area within which the second protrusions 22a and 22b contact the second limiting portions 31 and 32 and the ramps 37 and 38. The second protrusions 22a and 22b exit from them at the midpoint of the first angular range.

[0087] In response to the rotation of the seat back 4 from the middle position of the first angle range R2 to the end of the first angle range R2 adjacent to the locking range R1, the first protrusions 21a to 21c move in contact with the first limiting part 29, while the second protrusions 22a and 22b gradually increase the distance from the ramps 37 and 38.

[0088] In response to the rotation of the seat back 4 from the first angle range R2 to the locking range R1, the first protrusions 21a to 21c move away from the first limiting part 29, the cam 14 rotates in the locking direction and pushes the locking members 12A to 12C out radially outward, and the outer teeth 20 of the locking members 12A to 12C engage with the inner teeth 25 of the toothed plate 10 at the initial locking position P1 and are locked.

[0089] In this configuration, all the first protrusions 21a to 21c of the locking members 12A to 12C exit the first limiting portion 29 at the same time. Distance h2 does not need to be considered when the first protrusions 21a to 21c exit the first limiting portion 29. This allows for a reduction in the distance to the first allowing portion 28 and helps prevent tooth skipping between the external teeth 20 and the internal teeth 25.

[0090] The free range of the first angle range R2 of the seat back 4 (i.e., the second angle range R3) is the range from the position of the first protrusion 21a of the locking member 12A on the inner surface 29a of the first limiting part 29 to the position where the second protrusion 22a of the locking member 12A collides with the end face of the second step 35 of the second limiting part 32.

[0091] Therefore, the reclining device for a vehicle seat according to this embodiment is configured to restrict the locking members 12A to 12C from moving radially outward within a second angle range R3, including a first angle range R2 including the forward tilt of the seat back 4. This helps to prevent dragging noise caused by the contact between the external teeth 20 and the internal teeth 25.

[0092] When the seat back 4 returns from the free range R3 to the locked range R1 and is locked, this embodiment helps to reduce the distance between the external teeth 20 and the internal teeth 25 while the first protrusions 21a to 21c are in contact with the first limiting part 29, and at the same time stabilizes the engagement between the external teeth 20 of the locking members 12A to 12C and the internal teeth 25 of the toothed plate 10. This reduces the possibility of teeth skipping at the initial locking position P1 when returning from the free range R3 to the locked range R1.

[0093] <Second Embodiment>

[0094] Figure 12 and Figure 13 A reclining device for a vehicle seat according to a second embodiment of the present invention is shown. The basic construction of the second embodiment is the same as that of the first embodiment, wherein the same elements are indicated by the same reference numerals. The second embodiment eliminates one of the second protrusions and one of the second limiting portions. Figure 12 This is the front view viewed from the toothed plate side. Figure 13 This is an operational illustration diagram that unfolds to show the relationship between the first limiting portion and the first allowing portion of the toothed plate according to the second embodiment and each of the first protrusions, as well as the correspondence between the second limiting portion and the second allowing portion and the second protrusions.

[0095] Specifically, such as Figure 12 and Figure 13 As shown, among the first to third locking members 12A to 12C, the second protrusion 22b of the second locking member 12B is eliminated, and only the second protrusion 22a of the first locking member 12A is retained. Among the two second limiting portions 31 and 32 formed in the inner peripheral wall surface 27b of the second recess 27, the second limiting portion 32 corresponding to the second protrusion 22b is eliminated, and only the second limiting portion 31 configured to face the second protrusion 22a within the second angle range is retained.

[0096] Although the position of the second protrusion 22a is the same as in the first embodiment, the second limiting portion 31 includes a ramp 37 at its first end in the circumferential direction and a ramp 39 at its second end in the circumferential direction. Therefore, the second protrusion 22a and the second limiting portion 31 are formed such that when the toothed plate 10 rotates in the opposite direction relative to the substrate 9, the first protrusions 21a to 21c and the first limiting portion 29 are arranged in the same position, similar to normal rotation.

[0097] Although the basic operation and effects of the second embodiment are the same as those of the first embodiment, the elimination of the second protrusion 22b and the second limiting part 32 allows the toothed plate 10 to be interchangeable between the left and right structures of the reclining device. This allows the use of the same pair of toothed plates 10 in the case of left and right paired reclining devices for vehicle seat 2 or in the case of left and right symmetrical seats for driver's seat and passenger seat, and helps to reduce the number of parts and reduce manufacturing and component management costs.

[0098] The second embodiment, employing a single second protrusion 22a, eliminates the need for arranging two second protrusions with radial displacement as illustrated in the first embodiment. This facilitates radial layout and reduces the radial diameter of the rearward tilt 5.

[0099] <Third Embodiment>

[0100] Figure 14 A third embodiment of the invention is shown, which is configured to retract the three locking members 12A to 12C directly inward by using an annular release plate 40 that can rotate integrally with the cam 14. The annular release plate 40 is disclosed as release plate 50 in the drawings of Japanese Patent Application Publication No. JP 2018-023583A.

[0101] Figure 14 This is a cross-sectional view of the tilting device, showing the state in which the external teeth 20 of the locking members 12A to 12C are engaged with the internal teeth 25 of the toothed plate 10 within the locking range R1. In the figure, reference numeral 41 indicates a third recess formed inside the second recess 27 of the toothed plate 10. Reference numeral 42 indicates a release groove formed in the release plate 40.

[0102] According to the third embodiment, the release plate 40 is disposed within the second recess 27. With this in mind, the third recess 41 is formed in an annular shape inside the second recess 27 about the rotation center of the toothed plate 10, and the second limiting portion 31 and the second allowing portion 33 are formed on the outer peripheral inward surface of the third recess 41. The second limiting portion 32 may also be formed similarly to that in the first embodiment.

[0103] The three locking members 12A to 12C each include a second protrusion configured to engage with the release groove 42 of the release plate 40, which is separate from the first protrusions 21a to 21c configured to engage with the first restricting portion 29. The second protrusion 22a of the axially projecting locking member 12A is configured to penetrate the interior of the third recess 41 and face the second allowable portion 33 and the second restricting portion 31 radially.

[0104] Two second protrusions 22a and 22b can be formed in two adjacent locking members 12A and 12B, similar to the first embodiment. In this case, as in the first embodiment... Figure 6 and Figure 7 As shown, the second allowable portion 33 and the two second restrictive portions 31 and 32 are formed in a stepped manner on the outer peripheral inward surface of the third recess 41 (i.e., arranged to form steps). The two second protrusions 22a and 22b are arranged in a radially displaced position, and the release groove 42 is also arranged in a radially displaced position.

[0105] The other structures of the third embodiment are the same as those of the first and second embodiments, and it exhibits the same effects as the first embodiment.

[0106] <Fourth Embodiment>

[0107] Figure 15 A fourth embodiment of the invention is shown, which is configured to retract locking members 12A to 12C radially inward using cam 14 as shown in the figures of Japanese Patent Application Publication No. JP 2009-118940A. Figure 15 In the locked state, the outer teeth 20 of the locking members 12A to 12C and the inner teeth 25 of the toothed plate 10 engage with each other within the locking range R1.

[0108] The fourth embodiment employs a guide plate 43 disposed inside the second recess 27 and configured to rotate integrally with the toothed plate 10. The guide plate 43 includes an arc-shaped guide hole 44 surrounding the rotation center of the toothed plate 10. A second allowable portion 33 and a second restrictive portion 31 are formed on the outer peripheral surface of the guide hole 44.

[0109] The three locking members 12A to 12C each include a first protrusion 21a to 21c, and one locking member 12A includes a second protrusion 22a configured to engage with a guide hole 44 on its inner side. The axially projecting second protrusion 22a is inserted into the guide hole 44 and configured to face the second allowable portion 33 and the second restrictive portion 31 radially. Alternatively, two second protrusions 22a and 22b may be formed in the two locking members 12A and 12B, respectively, similar to the first embodiment.

[0110] In this case, as in the first embodiment Figure 6 and Figure 7 As shown, the second allowable portion 33 and the second restrictive portion 31 are formed in a stepped manner on the inner surface of the outer periphery of the guide hole 44 (i.e., arranged to form a step). The two second protrusions 22a and 22b are arranged radially offset.

[0111] It also allows the elimination of the guide plate driving the rotor and the outer peripheral inward surface of the guide hole 44, so that a portion of the tooth plate 10 protrudes toward the second recess 27.

[0112] The other constructions of the fourth embodiment are the same as those of the first embodiment, which presents the same effects as the first embodiment.

[0113] The present invention is not limited to the embodiments described above.

[0114] Exemplary aspects of a reclining device for a vehicle seat according to the above embodiments are described below.

[0115] According to one aspect of the invention, a reclining device for a vehicle seat is provided, the reclining device comprising: a base member fixed to a first of a lower support of a seat cushion and an upper support of a seat back; a toothed member fixed to a second of the lower and upper supports, arranged to overlap with the base member and configured to rotate relative to the base member; a first recess shaped as a circle, formed inside the outer periphery of the toothed member and centered on the rotation center of the toothed member; an inner tooth formed on the inner circumferential surface of the first recess; a plurality of locking members arranged between the base member and the toothed member and configured circumferentially, wherein each locking member includes an outer tooth that is radially movable to engage with the inner tooth in a locked position and release the engagement in an unlocked position; a cam arranged radially inside the locking members and configured to move the locking members between a locked position and an unlocked position; and a biasing member biasing the locking members via the cam along a locking direction that is the direction of engagement of the inner and outer teeth. The toothed member includes a second recess, which is annularly shaped and formed radially inside the first recess, centered on the rotation center of the toothed member. Each locking member includes a first protrusion projecting toward the second recess and configured to radially face the outer inner circumferential surface of the second recess. The second recess includes a plurality of first allowable portions and a plurality of first restrictive portions. The first allowable portions are configured to face the first protrusions with a gap, respectively, within a locking range on the reclining side from an initial locking position of the seat back relative to the seat cushion, and allow the locking members to move to the locking position. The first restrictive portions are configured to be positioned radially inside the first allowable portions within a first angular range on the forward reclining side from the initial locking position of the seat back relative to the seat cushion, and respectively contact the first protrusions radially and restrict movement of the first protrusions in the engagement direction. At least one locking member includes a second protrusion positioned radially inside the first protrusion and projecting toward the inner side of the second recess. The toothed member includes a second restrictive portion. The second limiting part is configured to be further set within a second angle range on the forward tilt side from a position that at least partially overlaps with the initial locking position of the seat back on the forward tilt side, and to contact the second protrusion of one of the locking members at a position radially inward relative to the position where the first protrusion contacts the first limiting part.

[0116] The aforementioned aspects of the invention allow a locking member, including a second protrusion, to smoothly transition from a state where the first protrusion rests on a first limiting portion to a state where the second protrusion rests on a second limiting portion, from a position where it is further positioned within a second angle range on the tilting side relative to a position at least partially overlapping with the initial locking setting on the tilting side of the seat back. Even when the first protrusion of the locking member passes over the first limiting portion facing the first protrusion and moves from the tilting direction to a first allowable portion adjacent to the first limiting portion, this also allows the locking member to be held in the unlocked state.

[0117] Furthermore, when the seat back is rotated backward from the forward-leaning position and locked within the locking range, the first protrusions of all locking members contact the first limiting portion within a first angle range. Then, the outer teeth of the locking members engage with the inner teeth of the toothed members at the initial locking position within the locking range (i.e., at the initial locking position). This helps stabilize the timing of engagement between the outer and inner teeth and shortens the distance between the outer and inner teeth when they are in contact with the first protrusions and the first limiting portion, thereby reducing the occurrence of tooth skipping when returning from the free region (i.e., the free range) to the locking region (i.e., the locking range).

[0118] Furthermore, even if the locking member is not fully retracted in the engagement release direction (i.e., radially inward direction) when the seat back is rotated forward from the locking range to the first and second angle ranges using the operating member, although the first protrusion of the locking member may collide with the side surface of the first restraint portion, the first protrusion of the locking member disperses and receives the collision load at that position. This helps to suppress the occurrence of compression and / or deformation of the first protrusion and the first restraint portion.

[0119] According to another preferred aspect, the second limiting portion includes a ramp. The ramp is configured such that, at least within a range where the first and second angle ranges overlap, in response to rotation of the seat back in the forward tilting direction, one of the locking members moves radially inward relative to the position where it contacts the first protrusion and the first limiting portion, in a direction that releases engagement between the external and internal teeth.

[0120] This aspect of the invention helps to position a locking member in a state where the first protrusion contacts the first limiting portion, so that the position of the locking member in a state where the second protrusion contacts the second limiting portion is further radially inward (i.e., toward the unlocked position). Even if other locking members move outward within the second angle range through the gap with the cam, this also prevents dragging noise caused by the contact between the inner teeth of the toothed member and the outer teeth of other locking members excluding the second protrusion.

[0121] Furthermore, when the seat back is raised from the maximum forward tilt position within the second angle range and rotated to the first angle range, the second protrusion helps to move from a state in which the second protrusion of at least one locking member contacts the second limiting portion to a state in which the first protrusion contacts the first limiting portion via the offset of the ramp, thereby allowing the locking member to move smoothly in the direction in which the first protrusion contacts the first limiting portion.

[0122] Furthermore, when the seat backrest tilts forward from the locking range to the first angle range and the second angle range, even if the second protrusion of at least one locking member is in a position where it is expected to collide with the second limiting part, the ramp of the second limiting part causes the second protrusion to move in the contact direction without collision, and allows the seat backrest to tilt forward smoothly.

[0123] According to another preferred aspect, the ramp of the second limiting portion is configured to contact the second protrusion of one of the locking members, and thereby: when the seat back is in the forward-tilting end position within the first angle range, at least one of the first protrusions of the locking member faces the first limiting portion radially with a gap; and in response to the rotation of the seat back from the forward-tilting end position toward the rearward direction, the first protrusion of the locking member moves radially outward and contacts the first limiting portion at a middle position within the first angle range.

[0124] According to this aspect, when the seat back rotates from the free range to the locked range, the first protrusion of the locking member separates from the first limiting part in the unlocking direction via a radial gap when the seat back is in the maximum forward tilt position within the second angle range. Then, the second protrusion moves radially outward along the slope of the second limiting part, which is the engagement direction. The first protrusion contacts the first limiting part at the middle position of the first angle range. At the maximum forward tilt locking position within the locking range, the first protrusion separates from the first limiting part, the locking member moves radially outward, and the seat back locks in the initial locking position. This allows the seat back to tilt smoothly backward.

[0125] According to another preferred aspect, each of the first limiting portions of the toothed member and the corresponding first protrusion of the locking member are located at the same position radially relative to the rotation center of the toothed member. The first limiting portions of the toothed member and the first protrusions of the locking member, which face each other respectively, are configured such that, at least in the orientation of the toothed member in the direction of rotation, the first orientation for rotating the seat back in the rearward direction is separated from each other at the same position.

[0126] This aspect of the invention causes the first protrusions of the locking member to disengage from their respective first restrictive portions at the same time when transitioning from the free range (i.e., the first angular range R2) to the locking range. This helps to stabilize the engagement timing of the locking member.

[0127] According to another preferred aspect, each locking member is supported by an axis formed in the base member, wherein the outer teeth and first protrusion of each locking member are located on a first side transversely across the axis in the rotational direction of the tooth member. A second protrusion of at least one locking member is located on a second side transversely across the axis in the rotational direction of the tooth member. A second limiting portion of the tooth member is formed in the inner peripheral wall surface of the second recess.

[0128] This aspect of the invention provides a first limiting portion and a second limiting portion on the outer and inner peripheral walls of the second recess of the toothed member, respectively, and helps to reduce the axial and radial lengths. This helps to reduce the size of the tilting device.

[0129] According to another preferred aspect, the locking member includes a first locking member, a second locking member, and a third locking member. Each of the first and second locking members includes a second protrusion. The toothed member includes a pair of second limiting portions, each second limiting portion radially facing the corresponding second protrusion of the first and second locking members within a second angular range of the seat back. The third locking member is located superiorly relative to the rotation center of the toothed member.

[0130] According to this aspect of the invention, in the free range where the first protrusion is radially separated from the first limiting portion (i.e., a portion of the second angular range in the direction of further forward tilting relative to the locking range), the movement of the first and second locking members radially outward (i.e., in the direction of meshing between the external and internal teeth) is restricted due to the contact between the second protrusions of the first and second locking members and the second limiting portion. The third locking member is positioned upper relative to the rotation center of the tooth member and is held in a lower position and suppressed from upward movement in the free region due to gravity. This helps to suppress dragging noise caused by the contact between the external teeth of the first, second, and third locking members and the internal teeth of the tooth member.

[0131] Furthermore, within the second angular range, the locking member does not move in the direction of engagement with the external teeth (i.e., radially outward). Therefore, the radial contact between the second protrusion and the second limiting portion relative to the rotation center of the toothed member allows the radial positions of the first and second locking members to approximate the radial position of contact between the first protrusion and the first limiting portion. This helps to reduce the radial dimension of the pitching device.

[0132] According to another preferred aspect, the radial lengths of the pair of second limiting portions from the rotation center of the toothed member are different from each other. The toothed member includes a second allowable portion located between the pair of second limiting portions and includes a plurality of steps, each step being continuously formed circumferentially between the second allowable portion and the corresponding second limiting portion of the pair of second limiting portions. Within a second angular range, a second protrusion of the first of the first locking member and the second locking member facing the second limiting portion with the larger radius in the second limiting portion contacts the second limiting portion with the larger radius in the second limiting portion, thereby restricting the movement of the first of the first locking member and the second locking member in the meshing direction, and within the locking range, facing the second limiting portion with the smaller radius in the second limiting portion with a gap, thereby allowing the movement of the first of the first locking member and the second locking member in the meshing direction. Within the second angular range, the second protrusion of the second of the first locking member and the second locking member, which faces the second limiting part with the smaller radius in the second limiting part, contacts the second limiting part with the smaller radius in the second limiting part, thereby restricting the movement of the second of the first locking member and the second locking member in the engagement direction. Furthermore, within the locking range, it faces the second allowing part with a gap, thereby allowing the movement of the second of the first locking member and the second locking member in the engagement direction.

[0133] According to this aspect of the invention, the inner outer peripheral surface of the second recess includes two second restrictive portions and one second allowable portion. This allows for sufficient freedom of movement and thereby reduces the radial dimension of the tilting device.

[0134] Explanation of reference numerals in the attached figures

[0135] 1. Rear tilting device

[0136] 3. Seat cushion

[0137] 4. Seat backrest

[0138] 5. Backward tilt

[0139] 6. Lower support

[0140] 7. Upper bracket

[0141] 9. Substrate (base component)

[0142] 10. Tooth plate (tooth component)

[0143] Locking components 12A, 12B, and 12C

[0144] 13. Helical spring (biased component)

[0145] 14 Cams

[0146] 20 External teeth

[0147] 21a, 21b, 21c First protrusion

[0148] 22a, 22b Second protrusion

[0149] 25 internal teeth

[0150] 26 First recess

[0151] 27 Second recess

[0152] 27a Outer peripheral wall surface (inner peripheral surface of the first recess)

[0153] 27b inner peripheral wall

[0154] 28 First Permitted Department

[0155] 29 First Restriction Section

[0156] 31, 32 Second Restriction Section

[0157] 33 Second Permitted Department

[0158] Steps 34, 35, and 36

[0159] 37, 38, 39 Slopes

Claims

1. A reclining device for a vehicle seat, the reclining device comprising: The base component is fixed to the first of the lower support of the seat cushion and the upper support of the seat back. A toothed member, which is fixed to the second of the lower and upper supports, is arranged to overlap with the base member and is configured to rotate relative to the base member; The first recess, which is circular in shape, is formed on the inner side of the outer periphery of the tooth member and is centered on the rotation center of the tooth member; Internal teeth, which are formed on the inner circumferential surface of the first recess; Multiple locking members are arranged between the base member and the tooth member and configured circumferentially, wherein each locking member includes an external tooth that is radially movable to engage with an internal tooth in a locked position and release the engagement in an unlocked position; A cam is arranged radially inward relative to the locking member and configured to move the locking member between a locked position and an unlocked position; as well as A biasing member that biases a locking member via a cam along a locking direction that is the direction of meshing of internal and external teeth; in: The toothed member includes a second recess, which is shaped as an annular shape, formed radially inside the first recess, and centered on the rotation center of the toothed member; Each locking member includes a first protrusion that projects toward the second recess and is configured to face the outer inner circumferential surface of the second recess in a radial direction; The second recess includes a plurality of first allowable portions and a plurality of first restrictive portions; The first allowable part is configured to face the first protrusion with a gap between it and the first protrusion within a locking range on the reclining side, starting from the initial locking position of the seat back relative to the seat cushion, and to allow the locking member to move to the locking position. The first limiting part is configured to be set within a first angle range on the forward tilt side from the initial locking position of the seat back relative to the seat cushion, positioned radially inward relative to the first allowing part, and respectively contacting the first protrusion in the radial direction and limiting the movement of the first protrusion in the engagement direction. At least one locking member includes a second protrusion positioned radially inward relative to the first protrusion and projecting toward the inside of the second recess; The toothed component includes a second limiting part; and The second limiting part is configured to be further set within a second angle range on the forward tilt side from a position that at least partially overlaps with the initial locking position of the seat back on the forward tilt side, and to contact the second protrusion of one of the locking members at a position radially inward relative to the position where the first protrusion contacts the first limiting part.

2. The tilting device as described in claim 1, wherein: The second limiting section includes a ramp; and The ramp is configured such that, at least within a range where the first and second angle ranges overlap, in response to rotation of the seat back in the forward tilting direction, one of the locking members moves radially inward relative to the position of contact between the first protrusion and the first limiting portion in the direction of engagement release between the external and internal teeth.

3. The tilting device as described in claim 2, wherein: The ramp of the second limiting part is configured to contact the second protrusion of one of the locking members, and thereby: When the seat back is in the forward-tilting end position within the first angle range, at least one of the first protrusions of the locking member faces the first limiting part radially with a gap; and In response to the rotation of the seat back from the forward-leaning end position toward the rearward direction, the first protrusion of the locking member moves radially outward and contacts the first limiting part at a position in the middle of the first angle range.

4. The tilting device as described in claim 1, wherein: Each of the first protrusions of the first limiting portion of the toothed member, corresponding to the first protrusion of the locking member, is located radially at the same position relative to the rotation center of the toothed member; and The first limiting portion of the toothed member and the first protrusion of the locking member, which face each other respectively, are configured such that, at least in the rotational direction of the toothed member, the first orientation for rotating the seat back in the backward tilting direction is separated from each other at the same position.

5. The tilting device as described in claim 1, wherein: Each locking member is supported by an axis formed in the base member, wherein the external teeth and the first protrusion of each locking member are located on the first side transversely across the axis in the rotational direction of the tooth member; At least one locking member has a second protrusion that is transverse to the axis and located on the second side in the direction of rotation of the toothed member; and The second limiting part of the toothed member is formed in the inner peripheral wall surface of the second recess.

6. The tilting device as claimed in claim 1, wherein: The locking components include a first locking component, a second locking component, and a third locking component; Each of the first locking member and the second locking member includes a second protrusion; The toothed member includes a pair of second limiting portions, each of which faces the corresponding second protrusion of the first locking member and the second locking member radially within a second angular range of the seat back; and The third locking member is located on the upper side relative to the rotation center of the toothed member.

7. The tilting device as claimed in claim 6, wherein: The radial lengths of the pair of second limiting parts from the rotation center of the toothed member are different from each other; The toothed member includes a second allowable portion located between a pair of second restrictive portions, and includes a plurality of steps, each step being formed circumferentially continuously between the second allowable portion and the corresponding second restrictive portion of the pair of second restrictive portions; Within the second angular range, the second protrusion of the first of the first locking member and the second locking member, which faces the second limiting part with the larger radius in the second limiting part within the second angular range, contacts the second limiting part with the larger radius in the second limiting part, thereby restricting the movement of the first of the first locking member and the first of the second locking members in the engagement direction. Furthermore, within the locking range, it faces the second limiting part with the smaller radius in the second limiting part through a gap, thereby allowing the movement of the first of the first locking member and the first of the second locking members in the engagement direction. and Within the second angular range, the second protrusion of the second of the first locking member and the second locking member, which faces the second limiting part with the smaller radius in the second limiting part, contacts the second limiting part with the smaller radius in the second limiting part, thereby restricting the movement of the second of the first locking member and the second locking member in the engagement direction. Furthermore, within the locking range, it faces the second allowing part with a gap, thereby allowing the movement of the second of the first locking member and the second locking member in the engagement direction.

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