TILT ADJUSTMENT DEVICE AND SEAT

Abstract

A tilt adjustment device (6) includes: locking gears (60A to 60D) each meshing with internal teeth (32) of an internal gear (30); a cam (50) configured to move each locking gear radially; a guide support (20) with guide walls (25) configured to guide the locking gear radially; and a wedge (80) arranged between the cam (50) and the locking gear (60A, 60C) pressing the locking gear (60A, 60C).The cam (50) has: a pressure surface (52a) (wedge pressure part) configured to push the wedge (80) radially outward while maintaining a contact state with the wedge (80) during movement of the locking gear (60A, 60C) from a release position to a meshing position; and a bulge (55) facing the locking gear while maintaining a gap between the bulge and the locking gear during movement of the locking gear (60A, 60C) from the release position to the meshing position.

Description

Technical field

[0001] The present invention relates to a tilt adjustment device and a seat that includes the tilt adjustment device. Technical background

[0002] Conventional vehicle seats include a seat that incorporates a tilt adjustment device to hold a seat back (backrest) at a specific tilt angle, with the seat back being configured to be tiltable relative to a seat cushion (seat base) in a forward-backward direction.

[0003] For example, in Fig. Figure 15 illustrates a tilt adjustment device 70 described in patent literature 1, comprising a guide bracket 72, an internal gear 76 with a plurality of internal teeth 76a, three locking gears 180 (pawls), a cam 90 and three press elements 100.

[0004] The guide bracket 72 is an essentially circular plate element that is fixedly attached to a frame of a seat cushion and has three pairs of guide walls 73, 74 extending radially. The three pairs of guide walls 73, 74 are spaced apart from each other in a circumferential direction of the guide bracket 72.

[0005] The internal gear 76 is a link with a ring section fixed to a seat back and has internal teeth 76a provided via an inner circumferential surface of the same.

[0006] Each of the three locking gears 180 has a plurality of external teeth 82, each tooth configured to mesh with the associated internal tooth 76a of the internal gear 76, and has a pair of broad ends 81, each in contact with the associated guide walls 73, 74. The three locking gears 180 are spaced apart from each other in a circumferential direction of the internal gear 76 and are each radially movable along the guide walls 73, 74, which extend radially over a range between a meshing position, in which the external tooth 82 and the internal tooth 76a mesh, and a release position, in which the meshing is released.

[0007] Furthermore, each of the three locking gears 180 has outer teeth 82 and a cam-facing portion 83, which is located in a radially inner position opposite the outer teeth 82, so that it faces the cam 90. The cam-facing portion 83 has a projection 83a and an L-shaped hook 83b, which are spaced apart from each other in the circumferential direction.

[0008] The cam 90 is rotatable relative to the guide bracket 72 between a predetermined locking angle and an unlocking angle and is configured to move each of the three locking gears 180 radially from the release position to the meshing position by rotating from the unlocking angle to the locking angle.

[0009] The cam 90 has a main body 91 in a circular plate shape, three sets of L-shaped hooks 92, and shoulders 93, each facing the three locking gears 180 and projecting radially outward from the main body 91. Each hook 92 engages with the hook 83b of the associated locking gear 180 when the cam 90 is in the unlocking angle. Each shoulder 93 is configured to push the locking gear 180 radially outward during a rotation of the cam 90 from the unlocking angle to the locking angle (in a locking direction R), while remaining in contact with an outer circumferential surface of the hook 83b of the locking gear 180.

[0010] Each of the three press members 100 is surrounded by the associated guide wall 74, the projection 83a of the associated locking gear 180, and the cam 90. During rotation of the cam 90, the press member 100 is pressed from the unlocking angle to the locking angle by an outer circumferential surface of the hook 92 of the cam 90, in order to move outwards along the guide wall 74 in a radial direction of the cam 90. In this way, the press member 100 presses the locking gear 180 radially outwards by applying a pressing force on the projection 83a of the locking gear 180 radially outwards and in an inclined direction with respect to the circumferential direction.

[0011] That is, in the tilt adjustment device 70, during the rotation of the cam 90 from the unlocking angle to the locking angle (in the locking direction R), the shoulder 93 of the cam 90 pushes the locking gear 180 radially outwards and the outer circumferential surface of the hook 92 of the cam 90 pushes the press member 100 radially outwards to move the locking gear 180 radially outwards into the meshing position (i.e. a position in which the outer tooth 82 and the inner tooth 76a mesh).

[0012] It should be noted that a clearance is provided between each of the lateral ends 81, which are the opposite ends of the locking gear 180 in one lateral direction, and each of the guide walls 73, 74 of the guide bracket 72, in order to allow the locking gear 180 to move smoothly. In the Fig. Figure 15 illustrates a conventional tilt adjustment device 70. Due to the presence of play, when the cam 90 pushes the locking gear 180 forward to move the locking gear 180 radially outward toward the mesh position, the press member 100 tilts. Such tilting can make the position of the locking gear unstable, leading to concerns that the tilt adjustment device may be placed in an incompletely locked or half-locked state.

[0013] Furthermore, due to a fluctuation of the components, including the locking gear 180, the outer teeth 82 of the locking gear 180 may mesh with the inner teeth 76a of the inner gear 76 at the meshing position before the press member 100 presses in the locking gear 180, and the locking gear 180 may rattle in the locked state. List of oppositions patent literature

[0014] Patent literature 1: Japanese patent publication no. 5434969 Brief description of the invention

[0015] The present invention was made in view of the circumstances described above and one object thereof is to provide a tilt adjustment device which prevents a locking gear from rattling in a locked state and simultaneously stabilizes a position of the locking gear during movement.

[0016] A tilt adjustment device according to the present invention comprises: a guide bracket configured to be fixedly attached to one of the frames of a seat cushion and the other of the frame of a seat back; an internal gear configured to be fixedly attached to the other of the frame of the seat cushion and the frame of the seat back such that it faces the guide bracket and is rotatable relative to the guide bracket; a plurality of locking gears, each having a plurality of external teeth configured to mesh with a plurality of internal teeth of the internal gear, spaced apart from one another in a circumferential direction of the internal gear, and each movable along the guide bracket in a radial direction of the guide bracket over a range between a meshing position, in which the external teeth and the internal teeth mesh, and a release position, in which the meshing is released;a cam which is rotatable and configured relative to the guide mount between a predetermined locking angle and an unlocking angle, to move each of the locking gears radially from the disengaged position to the meshing position by rotating from the unlocking angle to the locking angle; a locking spring which rotates and pushes the cam from the unlocking angle to the locking angle;and a wedge arranged between at least one locking gear below the locking gears and the cam, pressing the locking gear. The guide mount has a plurality of pairs of guide walls facing each other and configured to guide the locking gears radially. At least one of the locking gears pressed by the wedge has a wedge contact surface extending in an inclined direction with respect to the radial direction and in contact with the wedge. The wedge is sandwiched between the wedge contact surface and an associated guide wall below the guide walls. The cam has: a wedge pressure portion configured to push the wedge radially outward while maintaining a contact state with the wedge during movement of the locking gear from the disengaged position to the engaged position;and a part facing the locking gear, which is facing the locking gear, while maintaining a gap between the part facing the locking gear and the locking gear pressed by the wedge during the movement of the locking gear from the release position to the meshing position. Brief description of the drawings Fig. Figure 1 is a perspective view illustrating an overall configuration of a seat incorporating a tilt adjustment device according to an embodiment of the present invention. Fig. Figure 2 is a perspective view showing a disassembled state of a connecting rod and a tilt adjustment mechanism in Fig. 1 illustrates. Fig. Figure 3 is a perspective exploded view of the tilt adjustment mechanism in Fig. 2. Fig. Figure 4 is a perspective view of a cam in Fig. 3. Fig. Figure 5 is an illustration of a guide bracket in Fig. 3 when viewed from an outer surface of the guide bracket. Fig. 6A is an illustration of a complete state of the tilt adjustment mechanism, which includes an internal gear, a pair of main locking gears, a pair of secondary locking gears, a pair of keys, the cam, the guide bracket, and a mounting ring. Fig. 3 in combination includes, in an axial view from outside the mounting ring. Fig. Figure 6B is an illustration of the complete state of the tilt adjustment mechanism, which includes the internal gear, the pair of main locking gears, the pair of secondary locking gears, the pair of keys, the cam, the guide bracket, and the mounting ring. Fig. 3 in combination includes, in a cross-sectional view along line AA in Fig. 6A. Fig. Figure 7 illustrates an arrangement of the cam, the pair of main locking gears, the pair of secondary locking gears, the pair of splines, and the internal gear, each in Fig. 3 are illustrated. Fig. Figure 8 is an enlarged view of a state in which the upper main locking gear is in Fig. 7 is in a comb position, the main locking gear is away from the cam and the wedge is in contact with the cam. Fig. Figure 9 is an illustration of the locations of the upper main locking gear in Fig. 7, of the wedge and the cam in a state in which the main locking gear is in a release position. Fig. Figure 10 is an illustration of the locations of the upper main locking gear in Fig. 7, of the wedge and the cam during a movement of the main locking gear from the release position to the mesh position. Fig. Figure 11 is an illustration of the locations of the upper main locking gear in Fig. 7, of the wedge and the cam during the movement of the main locking gear from the release position to the mesh position. Fig. Figure 12 is an illustration of the locations of the upper main locking gear in Fig. 7, of the wedge and the cam during the movement of the main locking gear from the release position to the mesh position. Fig. Figure 13 is an illustration of the locations of the upper main locking gear in Fig. 7, of the wedge and the cam in a state in which the main locking gear is in the comb position. Fig. Figure 14 illustrates a condition in which the pair of main locking gears and the pair of secondary locking gears are in Fig. 7 are located at the comb position. Fig. Figure 15 is a cross-sectional view of a structure of a conventional tilt adjustment device. Description of embodiments

[0017] A preferred embodiment of the present invention is described below with reference to the accompanying drawings.

[0018] As in Fig. Figure 1 illustrates a seat 1 according to the embodiment as a vehicle seat comprising: a seat cushion 2 for supporting the buttocks of an occupant; a seat backrest 3 located behind the seat cushion 2 to support the back of the occupant and tiltable in a forward-backward direction X of the seat 1 relative to the seat cushion 2; a sliding device 4 attached to a lower section of the seat cushion 2; and a tilt adjustment device 5.

[0019] The sliding device 4 is configured to guide the seat cushion 2 slidably in the forward-backward direction X of the seat 1 and to hold the seat cushion 2 in a specific position. According to the present invention, the seat does not necessarily have to include the sliding device 4.

[0020] The tilt adjustment device 5 includes as its main structure a tilt adjustment mechanism 6 which is configured to hold the seat back 3 at a specific tilt angle.

[0021] Specifically, it includes, as in Fig. 1 and Fig. Figure 2 illustrates the tilt adjustment device 5 according to the embodiment: a pair of tilt adjustment mechanisms 6; a connecting rod 7 connected to each of the tilt adjustment mechanisms 6; and a pair of resin bushings 8 to receive one corresponding bushing from opposite ends of the connecting rod 7. The resin bushings 8 can be omitted.

[0022] The two tilt adjustment mechanisms 6 are arranged on both sides of the seat 1 in a lateral direction Y of its side. Each of the tilt adjustment mechanisms 6 serves as a coupling to hold the seat back 3 at a specific tilt angle.

[0023] As in Fig. 3, Fig. 6A and Fig. Figure 6B illustrates that the tilt adjustment mechanism 6 comprises a guide bracket 20 in a circular plate shape, an internal gear 30, a pair of main locking gears 60A, 60C, and a pair of secondary locking gears 60B, 60D, a cam 50, two locking springs 40, a pair of keys 80, and a mounting ring 70. The internal gear 30 is arranged facing the guide bracket 20 and has a plurality of internal teeth 32. The pair of main locking gears 60A, 60C and the pair of secondary locking gears 60B, 60D are four locking gears 60A to 60D, each having a plurality of external teeth 63 that mesh with the associated internal teeth 32. The cam 50 is configured to move each of the four locking gears 60A to 60D in a radial direction of the guide bracket 20. The two locking springs 40 rotate and push the cam 50.Although two locking springs 40 are used in this embodiment, at least one locking spring may suffice. Each of the two wedges 80 can be arranged between at least one locking gear among the four locking gears 60A to 60D, specifically between one of the two main locking gears 60A, 60C, and the cam 50, in order to press the corresponding main locking gear 60A, 60C. The mounting ring 70 attaches the internal gear 30 to the guide bracket 20. The four locking gears 60A to 60D, the cam 50, the pair of wedges 80, and the two locking springs 40 are located between the guide bracket 20 and the internal gear 30.

[0024] As in Fig. Figure 7 illustrates the four locking gears 60A to 60D, that is, the pair of main locking gears 60A, 60C and the pair of secondary locking gears 60B, 60D, spaced apart from each other in a circumferential direction of the internal gear 30, each of the locking gears being movable along the guide support 20 in a radial direction of the guide support 20 over a range between a meshing position, in which the outer teeth 63 of each locking gear and the associated inner teeth 32 of the internal gear 30 mesh, and a release position, in which the meshing is released. Specifically, each of the main locking gears 60A, 60C has the external teeth 63 which are configured to mesh with the associated internal teeth 32 and achieves a tight mesh in response to a push by the cam 50 over the associated key 80.In contrast, each of the secondary locking gears 60B, 60D has external teeth 63 configured to mesh with the associated internal teeth 32, and such meshing with the internal teeth 32 is intended to complement the solid meshing (locking force) of the main locking gears 60A, 60C. In this embodiment, a small coil spring is used for each locking spring 40.

[0025] Here, the "tight meshing" of the main locking gear 60A, 60C means the meshing of the outer teeth 63 and the corresponding inner teeth 32, whereby their individual tooth surfaces are in press contact with each other. In contrast, the secondary locking gear 60B, 60D does not require such tight meshing as that of the main locking gear 60A, 60C, where its outer teeth 63 and the associated inner teeth 32 press against each other, but merely a meshing that complements the tight meshing (locking force) of the main locking gear 60A, 60C. Therefore, examples of the meshing of the outer teeth 63 of the secondary locking gear 60B, 60D with the associated inner teeth 32 may involve a state of weak meshing in which the tooth surface of the outer teeth and the tooth surface of the inner teeth are partially in contact with each other or slightly spaced apart from each other.

[0026] The guide bracket 20 is a plate member with a circular central hole 22. In this embodiment, the guide bracket 20 is configured to be fixed to a section around the rear of a frame 2a (specifically, a side frame, see figure). Fig. 1 to Fig. 2) to be attached to the seat cushion 2, which serves as one of a frame of the seat cushion 2 and a frame of the seat back 3.

[0027] Specifically, it includes, as in Fig. 3, Fig. 5, Fig. 6B and Fig. Figure 9 illustrates the guide bracket 20: a main body 21 with a disc shape and with the central hole 22 in a circular shape in the middle of it; two housing parts 23, each housing the locking springs 40; and a flange 24 extending along an outer circumference of the main body 21.

[0028] Each of the two housing parts 23 is recessed towards an outer surface 21a of the guide bracket 20, opens to an inner surface 21b of the main body 21 and communicates with the central hole 22. This configuration allows an outer end 41 of the locking spring 40 to project into an inner position of the central hole 22, with a coiled section of the locking spring 40 housed in the housing part 23.

[0029] As in Fig. 6B and Fig. Figure 7 illustrates that the guide bracket 20 further comprises a plurality of guide walls 25 (guide elements) configured to guide the four locking gears 60A to 60D in radial directions along the inner surface 21b (the facing surface) of the main body 21. The guide walls 25 are arranged at equal intervals in a circumferential direction around the central hole 22 and extend in the radial directions of the guide bracket 20. Specifically, the guide walls 25 are arranged in pairs and extend radially in four directions from the central hole 22, which serves as the center. Consequently, four pairs of guide walls 25 each guide the four locking gears 60A to 60D in the radial directions of the guide bracket 20.

[0030] The internal gear 30 is configured to be fixed to a lower section of a frame 3a (specifically a side frame, see Fig. 1 to Fig. 2) to be attached to the seat back 3, which serves as the other of the frame of the seat cushion 2 and the frame of the seat back 3, while facing the guide bracket 20.

[0031] As in Fig. 3, Fig. 6A and Fig. Figure 6B illustrates that the internal gear 30 includes a recess 31 which, in an axial view of the internal gear 30, has a circular shape and, in cross-section, a substantially recessed shape. The recess 31 has an inner circumferential surface 31a formed with the internal teeth 32 over the entire circumference of the inner circumferential surface 31a. The internal teeth 32 project from the inner circumferential surface 31a toward the center of rotation of the internal gear 30. The internal gear 30 is arranged such that a lower surface 31b defining the recess 31 faces the inner surface 21b (facing surface) of the main body 21 of the guide holder 20. The recess 31 has a through-hole 33 in its center. As shown in Figure 6B, the recess 31 has a through-hole 33 in its center. Fig. Figure 2 illustrates that the through-hole 33 is aligned with a through-hole 3b of the frame 3a of the seat backrest 3. The end of the connecting rod 7 and the end of the associated resin bushing 8 are inserted through the through-hole 33 into the tilt adjustment mechanism 6.

[0032] As in Fig. 3 and Fig. Figure 6B illustrates a circumferential edge section defining the recess 31 fitted to a curvature 26 of the guide bracket 20, that is, to the curvature 26 defined between the main body 21 and the flange 24 as shown in Fig. Figure 6B illustrates a fit in which the guide holder 20 and the recess 31 of the internal gear 30 face each other. This defines a radial position of the internal gear 30 relative to the guide holder 20.

[0033] Furthermore, the mounting ring 70 is firmly attached to the flange 24 by welding or other means to prevent the internal gear 30 from dislodging in the axial direction. In this way, the internal gear 30 is rotatably connected to the guide bracket 20 relative to it.

[0034] As in Fig. Figure 3 illustrates the four locking gear links 60A to 60D (i.e., locking plates), each having external teeth 63 configured to mesh with the associated internal teeth 32 of the internal gear 30, and having a substantially rectangular shape in a plan view. The locking gear links 60A to 60D are arranged to be movable along the inner surface 21b of the guide support 20 while being guided by the guide walls 25 on the inner surface 21b in the radial direction of the guide support 20. This allows each of the locking gear links 60A to 60D to be moved between the meshing position, where the external teeth 63 and the internal teeth 32 mesh, and the release position, where the meshing is released.Each of the locking gears 60A to 60D has a meshing groove 61, which is substantially arcuate and extends circumferentially along an inner circumferential surface of the locking gear. The meshing groove 61 is a groove that engages with an engaging projection 52 of the cam 50, as described below. Because the meshing groove 61 extends circumferentially, each of the locking gears 60A to 60D has a substantially L-shaped engagement projection 64 along its inner circumferential surface at a position located further inward in the radial direction of the guide holder 20 than the meshing groove 61. In other words, the L-shaped engagement projection 64 serves to engage with the engaging projection 52 of the cam 50.

[0035] As in Fig. 8 to Fig. As illustrated in Figure 12, the L-shaped engagement projection 64 has: an outer surface 64a facing the cam 50 on a radially inner side of the guide bracket 20; an engaging groove 61 engaging with the engaging projection 52 of the cam 50 at an inner position of the L-shaped engagement projection 64; a corner 64b at an outer position of the L-shaped engagement projection 64, i.e., opposite the engaging groove 61; and a side surface 64c facing a guide wall 25B of the guide bracket 20. The outer surface 64a is in the locked (meshing) state of the main locking gear 60A, 60C (see Figure 12). Fig. 12) facing a bulge 55 of the cam 50 at a distance from it. Corner 64b is defined by the outer surface 64a and the side surface 64c at the outer position of the L-shaped engagement projection 64. Corner 64b results from a chamfer to prevent contact with the bulge 55 during rotation of the cam 50 from the disengaged position to the engaged position. Specifically, corner 64b results from a chamfer to remove a radially inwardly projecting section, as shown in Fig. 8 represented by a long-stroke-double-short-stroke line, and to form an arc or line in the Fig. 8. Shape represented by a solid line.

[0036] As in Fig. 3 and Fig. Figure 7 illustrates the pair of main locking gears 60A, 60C facing each other and aligned in an up-down direction over the cam 50.

[0037] The pair of secondary locking gears 60B, 60D are at an angle of 90° to the pair of main locking gears 60A, 60C in the circumferential direction of the cam 50 and are facing each other and aligned over the cam 50.

[0038] As in Fig. 3 and Fig. 7 to Fig. Figure 8 illustrates that the pair of main locking gears 60A, 60C, which are radially oriented towards each other and aligned in the top-bottom direction, have, like the secondary locking gears 60B, 60D, the outer teeth 63 and the engagement projection 64, but differ from the secondary locking gears in that they each have a Fig. 8 shown wedge contact surface 67.

[0039] The wedge contact surface 67 is a slope extending in an inclined direction with respect to the radial direction along the inner circumference of the main locking gear 60A, 60C and is in contact with the wedge 80. The wedge contact surface 67 is circumferentially adjacent to the engagement projection 64. Specifically, the wedge contact surface 67 is located closer to one guide wall 25A of the pair of guide walls 25A, 25B, and the engagement projection 64 is located closer to the other guide wall 25B.

[0040] In this embodiment, the wedge 80 has a substantially triangular and pointed wedge shape and is in Fig. 8 between the wedge contact surface 67 of the main locking gear 60A, 60C and the guide wall 25, more precisely the guide wall 25A, which is closer to the wedge 80, arranged in a sandwich-like manner.

[0041] As in Fig. 8 to Fig. Figure 9 illustrates that the wedge 80 has a contact surface 80a, which has an arc shape and is in contact with the cam 50 (specifically a pressure surface 52a described below, which has an arc shape and forms an outer circumferential surface of the engaging projection 52), a guide wall contact surface 80c, which is in contact with the guide wall 25A, and a locking gear contact surface 80b, which is in contact with the wedge contact surface 67 of the main locking gear 60A, 60C.

[0042] As in Fig. Figure 8 illustrates that the guide wall contact surface 80c and the locking gear contact surface 80b define an angle θ between them, which in a rotational axial view of the cam 50 (in a direction perpendicular to the plane of Fig. 8) lies in a range of 30° to 70°, as the angle required so that the wedge 80 presses the main locking gear 60A, 60C with sufficient pressing force towards the guide wall 25B opposite the wedge 80.

[0043] The pair of secondary locking gears 60B, 60D differs from the main locking gears 60A, 60C by a shape that incorporates a key 80. Specifically, as shown in Fig. 3, Fig. 7 and Fig. Figure 14 illustrates the secondary locking gear 60B, 60D, which has a projection 65 corresponding to the wedge 80 and projects radially inwards on a radially inner side of the secondary locking gear. The projection 65 has a radially inner surface configured to come into contact with the cam 50, specifically with the pressure surface 52a, which has an arc shape forming the outer circumferential surface of the engaging projection 52.

[0044] The cam 50 is rotatable relative to the guide bracket 20 between a predetermined locking angle and an unlocking angle. As shown in Fig. 3 to Fig. 4 and Fig. Figure 6B illustrates that the cam 50 has a main body 51 and a shaft part S which projects in the axial direction of the cam 50 from the main body 51 towards the guide holder 20 and is located in the central hole 22 of the guide holder 20.

[0045] The main body 51 has four engaging projections 52, which serve as a plurality of actuating elements to move the four locking gears 60A to 60D radially. The four engaging projections 52 extend in such directions that they each engage with the grooves 61 to be brought into engagement (see Fig. 3) the four locking gears 60A to 60D can be brought into engagement, more precisely they extend in an essentially arc-shaped angle (essentially L-shaped) and at equal intervals in the circumferential direction.

[0046] As in Fig. 7 to Fig. As illustrated in Figure 8, the cam 50 has four pressure surfaces 52a, each of which comes into direct or indirect contact with the four locking gears 60A to 60D. This contact is accompanied by a rotation from the unlocking angle to the locking angle, with a rotational thrust force exerted by each locking spring 40. This force pushes and moves the four locking gears outwards in the radial directions of the cam 50 into their meshing positions. The four pressure surfaces 52a each form the outer circumferential surfaces of the four engaging projections 52. A pair of the pressure surfaces 52a, oriented in the top-bottom direction, are each in contact with the wedges 80 adjacent to the pair of main locking gears 60A, 60C. and the remaining pressure surfaces 52a each come into contact with the projections 65 of the pair of secondary locking gears 60B, 60D in order to push and move all locking gears 60A to 60D radially outwards from the cam 50 into the mesh positions.Each printed area 52a contains a curvature in an arc.

[0047] Specifically, each of the two pressure surfaces 52a, which are in contact with the wedges 80, serves as a wedge pressure element among the four pressure surfaces 52a, pressing the wedge 80 radially outwards while maintaining contact with the wedge 80 during movement of the main locking gear 60A, 60C from the disengaged position to the engaged position. Each of the two remaining pressure surfaces 52a serves as a projection pressure element, pressing the projection 65 radially outwards while maintaining contact with the projection 65 during movement of the secondary locking gear 60B, 60D from the disengaged position to the engaged position.

[0048] Furthermore, the cam 50 has a bulge 55 in each section between adjacent engaging projections 52 beneath the four engaging projections 52 on its outer circumferential surface. Each of the two bulges 55 beneath the four bulges 55 forms a portion facing the locking gear, which faces the main locking gear 60A, 60C, while maintaining a gap g between the portion facing the locking gear and the main locking gear 60A, 60C (specifically the engagement projection 64) during the movement of the main locking gear 60A, 60C from the disengaged position to the meshed position.Each of the two remaining bulges 55 forms a part facing the locking gear, which is oriented towards the secondary locking gear 60B, 60D, while maintaining a gap between the part facing the locking gear and the engagement projection 64 of the secondary locking gear 60B, 60D during the movement of the secondary locking gear 60B, 60D from the release position to the meshing position.

[0049] As in Fig. Figure 7 illustrates that the four pressure surfaces 52a each have sections that represent contact points P1, P2 (see Fig. 7) include, which serve as pressure sections to each come into contact with the four locking gears 60A to 60D at the comb positions and to hold the locking gears 60A to 60D at the comb positions when the cam 50 is in the predetermined locking angle.

[0050] The section containing contact point P1, as the pressure section of the pressure surface 52a, is configured to push the associated wedge 80, which is adjacent to a corresponding pair of main locking gears 60A, 60C, radially outward, even if the cam 50 exceeds the locking angle. In this embodiment, the section of the pressure surface 52a containing contact point P1 has an arc shape and is thus in near point contact with the contact surface 80a of the wedge 80 within a narrow area that includes contact point P1 and a circumference around it. Therefore, even if the cam 50 exceeds the locking angle, the section of the pressure surface 52a containing contact point P1 can push the wedge 80 radially outward while remaining in contact with the contact surface 80a.Here, “pressing, even if the cam exceeds the locking angle” means pressing during a period from the beginning of the meshing of the locking gear 60A, 60C, until one of the end faces of the main locking gear 60A, 60C, in its lateral direction opposite the wedge 80, comes into contact with the guide wall 25B of the guide bracket 20. The section of the pressure surface 52a containing the contact point P1 tilts from a contact section of the main locking gear 60A, 60C to come into contact with the pressure section at such an angle that the cam 50 engages the wedge 80 of the main locking gear 60A, 60C as it advances in the locking direction R (see figure). Fig. 10 to Fig. 13) can press beyond the predetermined locking angle.

[0051] The section of the pressure surface 52a containing contact point P2 can be configured to be in contact with the projection 65 of the secondary locking gear 60B, 60D at the meshing position to maintain the meshing state. For example, the section of the pressure surface 52a containing contact point P2 points in a normal direction that coincides with the direction of the outer circumferential surface of the projection 65 of the secondary locking gear 60B, 60D to prevent an increase in the pressure force on the secondary locking gear 60B, 60D regardless of any further advance of the cam 50 in the locking direction R beyond the predetermined locking angle.

[0052] The remaining configuration of cam 50 is described below.

[0053] As in Fig. 2 to Fig. Figure 4 illustrates that the main body 51 of the cam 50 has a rod engagement hole 54 in its center. The rod engagement hole 54 receives one end of the connecting rod 7, which engages with it through the through hole 33 of the internal gear 30. The connecting rod 7 is manually rotated to allow the cam 50 to rotate within the tilt adjustment mechanism 6.

[0054] As in Fig. Figure 4 illustrates that the shaft part S of the cam 50 has an outer circumferential surface S1 which is in contact with an inner circumferential surface 22a which defines the central hole 22 of the guide holder 20, and an engagement area (an engagement end 53b described below) for engagement with the outer end 41 of the locking spring 40.

[0055] In this embodiment, the shaft section S includes a plurality of projections 53 (two projections in this embodiment) that project axially from the main body 51. The outer circumferential surface S1 includes radially outer surfaces 53a of the two projections 53 in a radial view of the cam 50. Each of the radially outer surfaces 53a is curved in an arcuate shape in an axial view of the cam 50. Each projection 53 is preferably configured to have a semi-penetrating form when forming the cam 50.

[0056] In this embodiment, the engagement area on each of the two projections 53 is defined such that the engagement end 53b is an end of the projection in the circumferential direction of the cam 50. The engagement end 53b is one of the opposite ends 53b and 53c of the projection 53 in the circumferential direction thereof, that is, an end that rotates in a direction (clockwise direction). Fig. 4) indicates in which the engaging projection 52 engages with the groove 61 of a corresponding one of the four locking gears 60A to 60D in the circumferential direction of the cam 50.

[0057] The locking spring 40 rotates and pushes the cam 50 by the engagement of the outer end 41 of the locking spring 40 with the engagement end 53b of the projection 53 in a predetermined direction (the locking direction R of the cam 50, as shown in Fig. 10 to Fig. (shown in 13) from the unlocking angle to the locking angle. Specifically, press as shown in Fig. 10 to Fig. Figure 13 illustrates the four engaging projections 52 of the cam 50: the pair of wedges 80 that press the pair of main locking gears 60A, 60C; and the projections 65 of the pair of secondary locking gears 60B, 60D outwards in radial directions of the cam 50, and each locking spring 40 rotates and pushes the cam 50 in one direction to move each of the locking gears 60A to 60D into the meshing position in which the outer teeth 63 mesh with the inner teeth 32 of the inner gear 30.

[0058] The cam 50 is rotatably mounted relative to the guide holder 20 by means of the contact of the outer circumferential surface S1 of the shaft part S with the inner circumferential surface 22a, which defines the central hole 22 of the guide holder 20.

[0059] As described above, the radial position of the cam 50 relative to the guide holder 20 is determined by the contact of the inner circumferential surface 22a, which defines the central hole 22 of the guide holder 20, with the radially outer surfaces 53a (i.e. the outer circumferential surface S1 of the shaft part S) of the projections 53.

[0060] As in Fig. Figure 3 illustrates that the two locking springs 40 are each housed in the housing parts 23 on the inner surface 21b of the main body 21 of the guide holder 20 in such a way that they are evenly spaced around the central hole 22 in the circumferential direction, i.e. the locking springs 40 are arranged in the embodiment at the opposite positions across the central hole 22.

[0061] Each of the locking springs 40 in the embodiment is a coil spring resulting from a spiral winding of a strip-shaped thin metal plate and has an outer end 41 and an inner end 42. The inner end 42 engages with an engagement projection (not shown) located in the associated housing part 23 of the guide holder 20.

[0062] The outer end 41 engages with the engagement end 53b of the projection 53 of the cam 50. Such engagement enables each of the two locking springs 40 to rotatably push the cam 50 in such a direction that each of the four locking gears 60A to 60D is displaced from the disengaged position to the meshed position.

[0063] In a normal locked state in the tilt adjustment mechanism 6, as shown in Fig. 13 to Fig. As illustrated in Figure 14, the cam 50 is forced by the locking spring 40 in the locking direction R by a rotational thrust force. In this state, the respective pressure surfaces 52a of the two engaging projections 52 of the cam 50 press the pair of wedges 80, each arranged between each of the pair of main locking gears 60A, 60C and the cam 50, to forcefully push the pair of main locking gears 60A, 60C radially outward and hold each of the main locking gears in the meshing position. This configuration allows each outer tooth 63 of each gear to mesh firmly with each inner tooth 32 of the inner gear 30 (see a pressing force F11 in Figure 14). Fig. 14) and allows the clearance in the width direction of the main locking gear 60A, 60C to be smaller (tighter) (see a division force F2 in Fig. 13), and thus prevents rattling. Specifically, as in Fig. 11 to Fig. Figure 13 illustrates that when the wedge contact surface 67, which tilts with respect to the radial direction, in the main locking gear 60A, 60C receives a pressing force F0 from the wedge 80, the pressing force F0 is divided into a radial splitting force F1 and a circumferential splitting force F2. The radial splitting force F1 serves as the pressing force F11 in Fig. 14 to achieve the firm meshing of the main locking gear 60A, 60C and the circumferential division force F2 prevents the rattling of the main locking gear 60A, 60C.

[0064] Each bulge 55 of the cam 50 is always kept away from the associated L-shaped engagement projection 64 of each of the locking gears 60A to 60D. As in Fig. 8 and Fig. Figure 13 illustrates that the gap g between an outer surface 55a of the bulge 55 and the outer surface 64a of the L-shaped engagement projection 64 is maintained even in the locked state. Accordingly, the main locking gear 60A, 60C is not pressed by the cam 50, but is always pressed by the wedge 80.

[0065] In a case where a large load from outside the tilt adjustment device 5 acts in the locked state through the locking gears 60A to 60D, the curvature 55 can come into contact with the L-shaped engagement projection 64 to prevent the meshing of the locking gears 60A, 60D from being released.

[0066] In contrast, when the connecting rod 7 receives a rotary actuation force, the cam 50 rotates in the opposite direction (rotates in a direction opposite to the locking direction R1). Fig. 10 to Fig. 13) against the elastic force of each locking spring 40, in order to displace the four locking gears 60A to 60D towards the center. Specifically, when the Fig. 10 to Fig. 13 illustrated cams 50 rotate in the opposite direction to the locking direction R, the four engaging projections 52 of the cam 50 each with the grooves 61 to be engaged (see Fig. 3) The locking gears 60A to 60D engage to pull the four locking gears 60A to 60D towards the center of the cam 50. This action pulls the four locking gears 60A to 60D radially inwards, and each locking gear is moved from the meshed position to the disengaged position, so that it is in the unlocked state. The unlocked state allows the angle of the seat back 3 to be changed to any suitable angle. When, after the angle of the seat back 3 has been changed to the preferred angle, no further rotary actuation force is applied to the connecting rod 7, the locking state is restored by the rotary thrust force of each locking spring 40. Features of the embodiment (1) In the tilt adjustment mechanism 6, which serves as the main structure of the tilt adjustment device 5 in the embodiment, the cam 50 has: the pressure surface 52a of the engaging projection 52, which serves as the wedge pressure part to press the wedge 80 radially outwards while maintaining contact with the wedge 80 during movement of the main locking gear 60A, 60C pressed by the wedge 80 from the disengaged position to the meshed position; and the bulge 55, which forms the part facing the locking gear, while maintaining a gap between the part facing the locking gear and the locking gear 60A, 60C during movement of the locking gear 60A, 60C from the disengaged position to the meshed position.

[0067] As in Fig. 10 to Fig. Figure 13 illustrates that this configuration maintains the state in which the wedge 80 pressing the main locking gear 60A, 60C is pressed through the pressure surface 52a of the engaging projection 52, which serves as the wedge pressure part of the cam 50, during the movement of the main locking gear 60A, 60C from the release position to the mesh position.

[0068] The wedge 80, which is pressed radially outwards by the pressure surface 52a of the engaging projection 52, which serves as the wedge pressure part of the cam 50, constantly presses the main locking gear 60A, 60C against the guide wall 25B of the pair of guide walls 25, which is located opposite the wedge 80, with the circumferential pitch force F2 based on the pressing force F0, which the wedge contact surface 67, tilting with respect to the radial direction, receives from the wedge 80. This leads to the stabilization of the position of the main locking gear 60A, 60C during movement into the mesh position.

[0069] Furthermore, each locking spring 40 rotates and forces the cam 50, even after the movement of the main locking gear 60A, 60C into the mesh position, from the unlocking angle to the locking angle in the locking direction R. Accordingly, the pressure surface 52a of the engaging projection 52 of the cam 50, which serves as the wedge pressure part, maintains the state of pressing the wedge 80, which presses the main locking gear 60A, 60C radially outward, even after the movement of the main locking gear 60A, 60C into the mesh position, and the bulge 55, which forms the part facing the locking gear, maintains the gap between the part facing the locking gear and the locking gear 60A, 60C. In other words, the main locking gear 60A, 60C itself is only pressed at the comb position by the pressure surface 52a, which serves as the wedge pressure part.This makes the main locking gear 60A, 60C less susceptible to component movement, which could cause the outer teeth 63 and the inner teeth 32 to mesh before contacting the cam 50. This prevents the main locking gear 60A, 60C from rattling in the locked position.

[0070] (2) As in Fig. Figure 8 illustrates that in the tilt adjustment mechanism 6 in the embodiment the wedge 80 has the guide wall contact surface 80c, which is in contact with the guide wall 25A, and the locking gear contact surface 80b, which is in contact with the wedge contact surface 67 of the main locking gear 60A, 60C.

[0071] The guide wall contact surface 80c and the locking gear contact surface 80b define the angle θ between them, which, in a rotational axial view of the cam 50, lies in a range of 30° to 70°. This configuration enables the wedge 80 to continuously press the main locking gear 60A, 60C against the guide wall 25B with sufficient force during the movement of the main locking gear 60A, 60C from the disengaged position to the engaged position, thus further stabilizing the position of the main locking gear 60A, 60C during movement.

[0072] (3) As in Fig. Figure 8 illustrates that in the tilt adjustment mechanism 6, the part of the cam 50 facing the locking gear has the curvature 55, which curves radially outwards from the outer circumferential surface of the cam 50 and in the direction of the main locking gear 60A, 60C.

[0073] The main locking gear 60A, 60C has corner 64b at a radially inner end of the main locking gear (more precisely, corner 64b at the outer position of the L-shaped engagement projection 64) so ​​that it is closest to the bulge 55 when the cam 50 is in the unlocking angle.

[0074] Corner 64b results from a chamfer to avoid contact with the curvature 55 during the rotation of the cam 50 from the unlocking angle to the locking angle.

[0075] This configuration, which includes the corner 64b resulting from a chamfer on a radially inner side of the main locking gear 60A, 60C, allows the corner 64b to avoid contact with the bulge 55 during the rotation of the cam 50 from the unlocking angle to the locking angle itself in the case where the part facing the locking gear has the bulge 55 bulging radially outwards and towards the main locking gear 60A, 60C.

[0076] (4) The seat 1 according to the embodiment includes the seat cushion 2, the seat back 3, which is located behind the seat cushion 2 and is tiltable in the forward-backward direction of the seat, and the tilt adjustment mechanism 6 with the configuration described above to hold the seat back 3 at a specific tilt angle. This configuration stabilizes the position of the main locking gear 60A, 60C during movement and prevents rattling of the main locking gear 60A, 60C in the locked position. This prevents rattling of the seat back 3. Modifications (A) Although the embodiment shown here exemplifies the bulge 55 forming the part of the cam 50 facing the locking gear, the present invention is not limited to the bulge. The part facing the locking gear in the present invention can be configured to face the main locking gear 60A, 60C while maintaining a gap between the part facing the locking gear and the main locking gear 60A, 60C, and can thus be in the form of a smooth circumferential surface of the main body 51 of the cam 50, without being limited to the shape of the bulge 55. (B) Although the embodiment shows a configuration which includes the four locking gears 60A to 60D as a plurality of locking gears and the pair of main locking gears 60A, 60C, which are radially facing each other, each have the keys 80, the present invention is not limited to this configuration. In the present invention, at least one locking gear may have a key among the locking gears. (C) Although in the embodiment each wedge 80 has a substantially triangular shape, the present invention is not limited to the triangular shape. As in Fig.Figure 8 illustrates that the wedge 80 has a contact surface 80a which is in contact with the pressure surface 52a of the cam 50, and can have various shapes, as long as the wedge can be sandwiched between the wedge contact surface 67 and the guide wall 25A. The wedge in the present invention can thus have a circular, trapezoidal, or substantially pentagonal shape, without being limited to a triangular shape. The wedge with such a shape allows the main locking gear 60A, 60C to move radially outwards without rattling while pressing the main locking gear against the guide wall 25B. (D) Although in the embodiment the two locking springs 40 are uniformly spaced in the circumferential direction of the guide bracket 20, the present invention can include at least one locking spring, without being limited to the two springs. The tilt adjustment mechanism 6 can therefore be configured to include one locking spring or three or more locking springs. Various types of locking springs, including a leaf spring, a coil spring, a rubber spring, and an air spring, can be used for the locking spring, without being limited to the coil spring in the embodiment. (E) Although in the embodiment the guide bracket 20 is configured to be fixedly attached to the frame 2a of the seat cushion 2, and the internal gear 30 is configured to be fixedly attached to the frame 3a of the seat backrest 3, the present invention is not limited to this arrangement. The guide bracket 20 and the internal gear 30 can be arranged in reverse. Specifically, the internal gear 30 can be fixedly attached to the frame 2a of the seat cushion 2, and the guide bracket 20 can be fixedly attached to the frame 3a of the seat backrest 3. Overview of the design

[0077] The embodiment can be summarized as follows.

[0078] A tilt adjustment device according to the embodiment comprises: a guide bracket configured to be fixedly attached to one of the frames of a seat cushion and the other of the frame of a seat back; an internal gear configured to be fixedly attached to the other of the frame of the seat cushion and the frame of the seat back such that it faces the guide bracket and is rotatable relative to the guide bracket; a plurality of locking gears, each having a plurality of external teeth configured to mesh with a plurality of internal teeth of the internal gear, spaced apart from one another in a circumferential direction of the internal gear, and each movable along the guide bracket in a radial direction of the guide bracket over a range between a meshing position, in which the external teeth and the internal teeth mesh, and a release position, in which the meshing is released;a cam which is rotatable and configured relative to the guide mount between a predetermined locking angle and an unlocking angle, to move each of the locking gears radially from the disengaged position to the meshing position by rotating from the unlocking angle to the locking angle; a locking spring which rotates and pushes the cam from the unlocking angle to the locking angle;and a wedge arranged between at least one locking gear below the locking gears and the cam, pressing the locking gear. The guide mount has a plurality of pairs of guide walls facing each other and configured to guide the locking gears radially. At least one of the locking gears pressed by the wedge has a wedge contact surface extending in an inclined direction with respect to the radial direction and in contact with the wedge. The wedge is sandwiched between the wedge contact surface and an associated guide wall below the guide walls. The cam has: a wedge pressure portion configured to push the wedge radially outward while maintaining a contact state with the wedge during movement of the locking gear from the disengaged position to the engaged position;and a part facing the locking gear, which is facing the locking gear, while maintaining a gap between the part facing the locking gear and the locking gear pressed by the wedge during the movement of the locking gear from the release position to the meshing position.

[0079] In this configuration, the cam has: the wedge pressure portion to press the wedge radially outward while maintaining contact with the wedge during movement of the locking gear from the disengaged position to the engaged position; and the locking gear-facing portion, which faces the locking gear while maintaining a gap between the locking gear and the locking gear during movement of the locking gear from the disengaged position to the engaged position. This configuration maintains the condition in which the wedge pressure portion presses the wedge during movement of the locking gear from the disengaged position to the engaged position.

[0080] Since the wedge is pressed radially outwards by the wedge pressure element, the locking gear is always pressed against the guide wall of the pair of guide walls opposite the wedge with a circumferential pitch force based on a pressing force that absorbs the wedge contact surface tilting with respect to the radial direction. This stabilizes the position of the locking gear during movement into the mesh position.

[0081] Furthermore, the locking spring rotates and forces the cam itself, even after the locking gear has completed its movement into the engaged position, from the unlocking angle to the locking angle. Accordingly, the wedge-pressure portion of the cam maintains the radial outward pressure of the wedge even after the locking gear has completed its movement into the engaged position, and the portion facing the locking gear maintains the gap between itself and the locking gear. In other words, the locking gear itself, even in the engaged position, is only pressed by the wedge-pressure portion of the cam. Thus, the locking gear is less likely to be affected by component movement. This configuration prevents rattling of the locking gear in the locked position.

[0082] The configuration allows the wedge to continuously press the locking gear towards the guide wall with sufficient force during the movement of the locking gear from the release position to the mesh position, which further stabilizes the position of the locking gear during movement.

[0083] In the tilt adjustment device, preferably the part facing the locking gear has a bulge that curves radially outwards from an outer circumferential surface of the cam and in the direction of the locking gear, and the locking gear has a corner at a radially inner end of the locking gear such that it is closest to the bulge when the cam is in the unlocking angle, the corner resulting from a chamfer.

[0084] This configuration, which includes the corner resulting from a chamfer on a radially inner side of the locking gear, allows the corner to avoid contact with the bulge during rotation of the cam from the unlocking angle to the locking angle itself, even in the case where the part facing the locking gear has the bulge that curves radially outwards and towards the main locking gear.

[0085] A seat according to the present invention comprises: a seat cushion; a seat backrest located behind the seat cushion and tiltable in a forward-backward direction of the seat; and the tilt adjustment device to hold the seat backrest in a specific tilting angle.

[0086] The seat, which incorporates the tilt adjustment device described above, is able to stabilize the position of the locking gear during movement and prevent rattling of the locking gear in the locked position. This prevents rattling of the seat back.

[0087] The tilt adjustment device and the seat according to the present invention are each able to stabilize the position of the locking gear during movement and to prevent the rattling of the locking gear in the locked state. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP 5434969

[0014]

Claims

[1] Tilt adjustment device comprising: a guide bracket configured to be firmly attached to a frame of a seat cushion and a frame of a seat back; an internal gear that is configured to be fixed to the other by the frame of the seat cushion and the frame of the seat back in such a way that it faces the guide bracket and is rotatable relative to the guide bracket; a plurality of locking gears, each having a plurality of external teeth configured to mesh with a plurality of internal teeth of the internal gear, spaced apart from each other in a circumferential direction of the internal gear, and each movable along the guide support in a radial direction of the guide support over a range between a meshing position where the external teeth and internal teeth mesh and a release position where the meshing is released; a cam which is rotatable and configured relative to the guide mount between a predetermined locking angle and an unlocking angle, to move each of the locking gears radially from the release position to the meshing position by rotating from the unlocking angle to the locking angle; a locking spring that rotates and pushes the cam from the unlocking angle to the locking angle; and a wedge which is arranged between at least one locking gear below the locking gears and the cam and presses the locking gear, wherein The guide bracket has a plurality of pairs of guide walls facing each other and configured to guide the locking gears radially. at least one of the locking gears pressed by the wedge has a wedge contact surface that extends in an inclined direction with respect to the radial direction and is in contact with the wedge, the wedge is arranged sandwich-like between the wedge contact surface and an associated guide wall under the guide walls, and which has a cam: a wedge pressure element configured to push the wedge radially outward while maintaining a contact state with the wedge during movement of the locking gear from the release position to the mesh position; and a part facing the locking gear, which is facing the locking gear, while maintaining a gap between the part facing the locking gear and the locking gear pressed by the wedge during the movement of the locking gear from the release position to the mesh position. [2] Tilt adjustment device according to claim 1, wherein the part facing the locking gear has a curvature which curves radially outwards from an outer circumferential surface of the cam and in the direction of the locking gear, and The locking gear has a corner at a radially inner end of the locking gear, such that it is closest to the curvature when the cam is at the unlocking angle. the corner results from a chamfer. [3] Seat, encompassing: a seat cushion; a seat backrest located behind the seat cushion and which can be tilted in a forward-backward direction of the seat; and the tilt adjustment device according to claim 1 or 2 to hold the seat back in a specific tilt angle.

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