Seat reclining device

Abstract

This method suppresses vibrations and abnormal noises during operation while improving the efficiency of the wedge member forming process and reducing processing costs. [Solution] The device comprises a cylindrical bearing cylinder 4d provided on a first rotating body 4, a metal bearing 7 provided on a second rotating body 6 into which the bearing cylinder is inserted, and a pair of arc-shaped wedge members 9A and 9B arranged in an eccentric space 8 formed between the outer circumferential surface 4f of the bearing cylinder and the inner circumferential surface 7a of the metal bearing. Each wedge member has an outer circumferential side surface 9d that is radially opposed to the inner circumferential surface of the metal bearing, an inner circumferential side surface 9e that is radially opposed to the outer circumferential surface of the bearing cylinder, one end surface 9f that is perpendicular to the outer circumferential side surface and located opposite to one end surface of the first rotating body, and the other end surface 9g that is opposed to one end surface of the second rotating body. Each outer circumferential side surface is formed to be inclined downward at a predetermined angle from one end surface to the other end surface.

Description

Technical Field

[0001] The present invention relates to a seat reclining device capable of adjusting the angular position of a seat back with respect to a seat cushion mounted on, for example, a vehicle or the like.

Background Art

[0002] As this type of seat reclining device, for example, the one described in Patent Document 1 has been proposed.

[0003] This seat reclining device includes a first rotating body having a plurality of internal teeth that are so-called semi-cut from the axial direction on an annular inner peripheral surface, a second rotating body having an external tooth and a housing portion formed on an annular outer peripheral surface and having one or two fewer teeth than the internal teeth of the first rotating body, a cylindrical bearing cylinder integrally provided on the hole edge of the central hole of the first rotating body, and a housing hole formed inside the second rotating body and having a larger diameter than the outer diameter of the bearing cylinder. Further, in a state where the internal teeth of the first rotating body and the external teeth of the second rotating body are engaged, a pair of wedge members are arranged in an eccentric space formed between the inner peripheral surface of the housing hole and the outer peripheral surface of the bearing cylinder, and a driving member for driving the wedge members in the circumferential direction within the eccentric space is provided.

[0004] This driving member includes a cylindrical portion rotatably arranged inside the bearing cylinder, a flange portion integrally provided at one axial end portion of the cylindrical portion and covering the side surfaces of the respective wedge members, and a pressing portion integrally provided on the outer peripheral side of the cylindrical portion for pressing the respective wedge members from the circumferential direction to release the wedge action.

[0005] Then, the driving member transmits a rotational driving force from an electric motor through a female spline hole formed along the axial direction on the inner peripheral surface of the cylindrical portion. When the pressing portion rotates each wedge member once by this rotational driving force, the engagement between the internal teeth and the external teeth is displaced by the difference in the number of teeth, so that the relative rotational angle between the first rotating body and the second rotating body is displaced, and thereby the angular position of the seat back is displaced.

Prior Art Documents

[0006] [Patent Document 1] Japanese Patent Publication No. 2008-200442 [Patent Document 2] Japanese Patent Publication No. 2012-135573 [Overview of the project] [Problems that the invention aims to solve]

[0007] Each wedge member of the seat reclining device described in Patent Document 1 is formed parallel to the inner surface of the housing hole and the outer surface of the bearing cylinder, with the inner and outer circumferential sides of the wedge members being formed parallel to each other. Therefore, for example, if each of these wedge members tilts when it moves slightly back and forth in the axial direction between the inner surface of the housing hole and the outer surface of the bearing cylinder, the axial lower edge (corner) of the inner surface and the axial upper edge (corner) of the outer surface diagonally opposite to it may come into contact with the inner surface of the housing hole and the outer surface of the bearing cylinder. This can cause vibrations and abnormal noises due to repeated fluctuations of contact and non-contact between the inner and outer circumferential sides of each wedge member and the inner surface of the housing hole and the outer surface of the bearing cylinder.

[0008] Therefore, as described in Patent Document 2, the inner and outer circumferential sides of each wedge member are formed in a curved shape along the axial direction, and are formed as a first and second circular arc surface with relatively large radii of curvature, with the central part in the width direction protruding. This prevents contact between the lower edge of the inner circumferential side and the upper edge of the outer circumferential side of each wedge member and between the inner surface of the housing hole and the outer surface of the bearing cylinder, thereby suppressing the generation of vibration and abnormal noise.

[0009] However, the wedge members in the invention of Patent Document 2 are structurally complex to form and may result in high processing costs. Specifically, since each wedge member must have its inner and outer circumferential surfaces formed into arc-shaped surfaces, the forming method generally involves forging, which compresses both axial surfaces of the wedge member, followed by multiple processing steps. This leads to decreased processing efficiency and inevitably increases processing costs.

[0010] One of the objectives of this invention is to provide a seat reclining device that can improve the efficiency of the wedge member forming process and reduce processing costs while suppressing the generation of vibrations and abnormal noises during the operation of the device. [Means for solving the problem]

[0011] The present invention comprises a first rotating body having a plurality of internal teeth partially cut out from the axial direction on its annular inner circumferential surface; a second rotating body having a plurality of external teeth on its annular outer circumferential surface that mesh with the internal teeth of the first rotating body and have one or two fewer teeth than the internal teeth; a cylindrical bearing cylinder provided on one axial end face of either the first or second rotating body, projecting toward the other rotating body; and a bearing cylinder provided on either the first or second rotating body, into which the bearing cylinder is inserted, and on the central axis of the other rotating body. A vehicle seat reclining device comprising: a circular housing portion formed coaxially with the bearing; a circular eccentric space formed between the outer circumferential surface of the bearing cylinder and the inner circumferential surface of the housing portion, with the internal and external teeth meshed; a pair of arc-shaped wedge members arranged within the eccentric space, each with its base end facing the other from the circumferential direction; a biasing means for biasing the pair of wedge members in a direction that separates them from each other in the circumferential direction; and a drive member inserted into the eccentric space and pressing the pair of wedge members in the circumferential direction to rotate them, wherein Each wedge member has an arc-shaped outer circumferential side surface that is radially opposed to the inner circumferential surface of the housing and is in contact with at least a portion of the inner circumferential surface of the housing, and an arc-shaped inner circumferential side surface that is radially opposed to the outer circumferential surface of the bearing cylinder, and also has one end surface that is perpendicular to each of the outer circumferential side surfaces and is located opposite to one end surface of one of the rotating bodies in the axial direction, and the other end surface that is positioned opposite to one end surface of one of the rotating bodies, The wedge member is characterized in that at least each of the outer peripheral surfaces is formed in an inclined manner in the direction from one end face to the other end face, so as to increase the gap with the inner peripheral surface of the housing portion. [Effects of the Invention]

[0012] According to an aspect of the present invention, it is possible to improve the efficiency of the wedge member forming process and reduce processing costs while suppressing the generation of vibrations and abnormal noises when the device is in operation. [Brief explanation of the drawing]

[0013] [Figure 1] This is an exploded perspective view of the main components in one embodiment of a vehicle seat reclining device according to the present invention. [Figure 2] Figure 3 shows a cross-sectional view of the seat reclining device of the vehicle according to this embodiment, cross-sectionally indicated by line BB. [Figure 3] This figure shows the state in which the internal and external teeth of the first rotating body and the second rotating body used in this embodiment are meshed together. [Figure 4] This is a perspective view showing a pair of wedge members used in this embodiment. [Figure 5] This is a cross-sectional view along line AA in Figure 4. [Figure 6] This is an enlarged view of section B in Figure 2. [Figure 7] This figure shows the metal bearing used in this embodiment tilted relative to the wedge member, and is an enlarged view of section B in Figure 2, the same as Figure 6. [Modes for carrying out the invention]

[0014] Hereinafter, an embodiment in which the seat reclining device according to the present invention is applied to a vehicle will be described based on the drawings.

[0015] FIG. 1 is an exploded perspective view of main constituent members in an embodiment of a seat reclining device according to the present invention, FIG. 2 is a cross-sectional view of the seat reclining device of the vehicle in this embodiment taken along line B-B of FIG. 3, FIG. 3 is a view showing a state in which internal and external teeth of a first rotating body and a second rotating body provided in this embodiment are engaged with each other, and FIG. 4 is a perspective view showing a pair of wedge members provided in this embodiment.

[0016] As shown in FIGS. 1 and 2, the seat reclining device includes a lid member 2 coupled to a cushion side arm 1 provided on a seat cushion (not shown), a first rotating body 4 coupled to a back side arm 3 provided on a seat back (not shown), a drive bush 5 which is a drive member rotationally driven by an electric motor (not shown) provided on the seat back side, and a second rotating body 6 integrally coupled to the lid member 2. When a rotational driving force in a normal rotation direction or a reverse rotation direction is applied to the drive bush 5 by the electric motor, the first rotating body 4 rotates with respect to the lid member 2 at a high reduction ratio in a direction opposite to the rotation direction of the drive bush 5.

[0017] As shown in FIGS. 1 and 2, the lid member 2 is formed in a semi-circular disk shape by press-forming an iron-based metal material, and an insertion hole 2a into which an output shaft of an electric motor is inserted is formed through the center thereof. A first arc-shaped recess 2c is formed on the inner circumference of an annular outer peripheral portion 2b. On the inner circumferential surface of this first arc-shaped recess 2c, fitting internal teeth 2d for press-fitting a part of external teeth 6a of the second rotating body 6 described later are intermittently formed in the circumferential direction.

[0018] Also, on the radially inner side of the first arcuate recess 2c, a second arcuate recess 2e for accommodating the cylindrical protrusion 6c of the second rotating body 6 is formed. On the radially inner side of this second arcuate recess 2e, a third arcuate recess 2f for accommodating a ring spring 10 described later is formed. On the corresponding back side of these second and third arcuate recesses 2e and 2f, a second arcuate protrusion 2g and a third arcuate protrusion 2h are respectively formed. Further, in the second arcuate recess 2e, a plurality (six in this embodiment) of fitting protrusions 2i protruding toward the radially outer side are provided at equidistant positions in the circumferential direction. Each of these fitting protrusions 2i is welded while being fitted into six fitting recesses 1a formed in the cushion side arm 1.

[0019] As shown in FIGS. 1 and 2, the first rotating body 4 is formed in a disc shape from an iron-based metal material, and an annular recess 4b is formed on the radially inner side of the outer peripheral portion on the side of the lid member 2. A plurality of half-cut inner teeth 4a are formed on the inner peripheral surface of the annular recess 4b. Further, a through hole 4c is formed through the center, and a cylindrical bearing cylinder 4d extending axially from the hole edge on the side of the lid member 2 of the through hole 4c is integrally provided. Also, between the inner teeth 4a of the first rotating body 4 and the bearing cylinder 4d, a plurality (six in this embodiment) of protrusion portions 4e protruding in the direction of the back side arm 3 are provided at equidistant positions in the circumferential direction. Each of these protrusion portions 4e is formed by embossing through press forming, and is fitted into six fixing holes 3a formed in the back side arm 3, and this portion is welded.

[0020] As shown in FIGS. 1 and 2, the second rotating body 6 is formed in an annular shape from an iron-based metal material, and a plurality of outer teeth 6a are formed on the outer peripheral surface. In FIG. 2, the right side portion of these outer teeth 6a is press-fitted and joined to the fitting inner tooth portion 2d of the lid member 2 and is integrated with the lid member 2, while in FIG. 1, the left side portion meshes with the inner teeth 4a of the first rotating body 4.

[0021] The meshing between the internal teeth 4a of the first rotating body 4 and the external teeth 6a of the second rotating body 6 is such that the number of teeth on the external teeth 6a of the second rotating body 6 is set to be one or two fewer than the number of teeth on the internal teeth 4a. As a result, as shown in Figure 3, the center P of the second rotating body 6 is eccentric with respect to the center P1 of the first rotating body 4, and the meshing occurs only in a portion of the circumferential direction.

[0022] The second rotating body 6 has a circular housing hole 6b formed in the center, concentric with each external tooth 6a, and a cylindrical projection 6c is integrally provided on the edge of the housing hole 6b on the lid member 2 side, with the inner circumferential surface of this cylindrical projection 6c forming part of the housing hole 6b.

[0023] A cylindrical metal bearing 7, which is a ring-shaped sliding bearing, is press-fitted and fixed to the inner circumferential surface of the housing hole 6b. This metal bearing 7 has a coating of Teflon (registered trademark) or the like applied to at least its inner circumferential surface 7a to improve sliding properties, and its axial length is formed to be approximately the same as the axial length of the housing hole 6b, including the inner circumferential surface of the cylindrical projection 6c. By making the axial length of the metal bearing 7 longer to match the axial length of the housing hole 6b in this way, the sliding surface area between the inner circumferential surface 7a and the outer circumferential surface 11b of the guide plate 11, which will be described later, is increased, thereby reducing the surface pressure during sliding. The housing hole 6b and the metal bearing 7 constitute a housing section, and the inner circumferential surface 7a of the metal bearing 7 is the inner circumferential surface of the housing section.

[0024] The ring spring 10 is positioned axially between the flange portion 5b of the drive bush 5 and the inner surface of the cover member 2, and protruding ends 10a, 10a are provided at both opposing ends that project toward the first rotating body 4. These two protruding ends 10a, 10a are locked to a pair of wedge members 9A, 9B, which will be described later, via a guide plate 11.

[0025] An eccentric space 8 is formed between the inner circumferential surface 7a of the metal bearing 7 and the outer circumferential surface 4f of the bearing cylinder 4d of the first rotating body 4. As shown in Figures 1 to 4, a pair of wedge members 9A and 9B are arranged within this eccentric space 8 with their base ends facing each other.

[0026] Figure 5 is a cross-sectional view taken along line AA in Figure 4.

[0027] The pair of wedge members 9A and 9B are each formed from metal sheet material by press forming, and as shown in Figures 4 and 5, they are each formed in a substantially arc shape in plan view and are symmetrical. Furthermore, each wedge member 9A and 9B is formed such that the thickness gradually decreases from the base end 9a, 9a on one end to the tip end 9b, 9b on the other end in the circumferential direction. Semicircular spring locking grooves 9c, 9c are formed on the tip surfaces of each base end 9a, 9a.

[0028] As shown in Figures 1 and 3, the pair of wedge members 9A and 9B are biased by the spring force in a direction away from each other in the circumferential direction, with both protruding ends 10a, 10a of the ring spring 10 locked into the spring locking grooves 9c, 9c from opposite directions. In other words, the pair of wedge members 9A and 9B are biased by the spring force of the ring spring 10 in a direction away from each other in the circumferential direction, in order to always maintain a backlash-free state in the meshing of the external teeth 6a of the second rotating body 6 and the internal teeth 4a of the first rotating body 4. The biasing force of the ring spring 10 and the wedge effect increase the distance between the centers (eccentricity) of the external teeth 6a and internal teeth 4a within the eccentric space 8, pushing the second rotating body 6 upward in Figure 3. Therefore, the meshing between the external teeth 6a and the internal teeth 4a is deepened, creating a backlash-free state, and a gap-free state is maintained between the bearing cylinder 4d and the internal teeth 4a, and between the second rotating body 6 and the pair of wedge members 9A and 9B, without any play.

[0029] Figure 6 is an enlarged view of section B in Figure 2, and Figure 7 shows the metal bearing used in this embodiment tilted relative to the wedge member, and is an enlarged view of section B in the same Figure 2 as Figure 6.

[0030] As shown in Figures 4 to 6, each wedge member 9A and 9B has an arc-shaped outer peripheral side surface 9d that faces radially to the inner peripheral surface 7a of the metal bearing 7, an arc-shaped inner peripheral side surface 9e that faces radially to the outer peripheral surface 4f of the bearing cylinder 4d, and an arc-shaped end face 9f on the cover member 2 side and an arc-shaped end face 9g on the first rotating body 1 side, located in a direction perpendicular to the central axis of each wedge member 9A and 9B, that is, between the outer peripheral side surface 9d and the inner peripheral side surface 9e.

[0031] As shown in Figures 5 and 6, the outer peripheral side surface 9d and the inner peripheral side surface 9e are in contact with the opposing surface at least in part, and are formed in a downward sloping manner from one end surface 9f towards the other end surface 9g, with the gap between them increasing relative to the opposing surface. Specifically, as shown in Figure 6, the upper edge 9h on the one end surface 9f side of the outer peripheral side surface 9d is in contact with the inner peripheral surface 7a of the metal bearing 7, and is formed in a downward sloping manner with a predetermined inclination angle θ toward the other end surface 9g side, so that the lower edge 9i on the other end surface 9g side has the largest gap between it and the inner peripheral surface 7a of the metal bearing 7. On the other hand, the upper edge 9j on the one end surface 9f side of the inner peripheral side surface 9e is in contact with the outer peripheral surface 4f of the bearing cylinder 4d, and is formed in a downward sloping manner with a predetermined inclination angle θ toward the other end surface 9g side, so that the lower edge 9k on the other end surface 9g side has the largest gap between it and the outer peripheral surface 4f of the bearing cylinder 4d. As described above, the outer peripheral side surface 9d and the inner peripheral side surface 9e are formed in an inclined shape with the same inclination angle θ, and are straight and flat inclined surfaces relative to each other. Therefore, the cross-sectional shape of each wedge member 9A and 9B is formed to be approximately trapezoidal. In Figure 6, the inclined surfaces of the outer peripheral side surface 9d and the inner peripheral side surface 9e are formed to have a shear surface of more than 70% of the overall area from the upper edges 9h and 9j to the lower edges 9i and 9k. Although the inclination angles θ appear large in the drawing, in reality, the inclination angles are set to have a small inclination of about 0.02 mm, where the difference between the distance to the opposing surface from the closest upper edge 9h and 9j to the furthest lower edge 9i and 9k is approximately 0.02 mm.

[0032] Furthermore, when the metal sheet material is punched out in the shear direction using a precision press molding machine, the shear surface of the outer peripheral side 9d and the inner peripheral side 9e are formed as inclined surfaces.

[0033] A guide plate 11 is positioned on one axial end face 9f of the wedge members 9A and 9B. Within the eccentric space 8, the wedge members 9A and 9B are positioned on the first rotating body 4 side, while the guide plate 11 is positioned on the lid member 2 side.

[0034] As shown in Figures 1 and 2, the guide plate 11 is formed in a substantially arc shape from an iron-based metal material, with its inner circumferential surface 11a having approximately the same radius of curvature as the outer circumferential surface 4f of the bearing cylinder 4d, and its outer circumferential surface 11b having approximately the same radius of curvature as the inner circumferential surface 7a of the metal bearing 7. This guide plate 11 is capable of moving in the circumferential direction within the eccentric space 8 while maintaining a constant distance (eccentricity) between the centers of the outer teeth 6a and the inner teeth 4a.

[0035] Furthermore, as shown in Figures 1 and 2, the guide plate 11 has an arc-shaped protrusion 11c integrally provided on one side facing the lid member 2, and an arc-shaped elongated hole 11d is formed through it at approximately the center of the circumferential direction below the protrusion 11c, into which the protruding ends 10a, 10a of the ring spring 10 are inserted.

[0036] A drive bush 5 is positioned between the guide plate 11 and the cover member 2 to push and rotate a pair of wedge members 9A and 9B in the circumferential direction.

[0037] The drive bush 5 is formed entirely from a sheet of iron-based metal of a predetermined thickness by press forming, and as shown in Figures 1 and 2, it comprises a cylindrical portion 5a that is rotatably supported inside the bearing cylinder 4d of the first rotating body 4, a flange portion 5b integrally provided at one axial end of the cylindrical portion 5a and covering the sides of each wedge member 9A, 9B, a pressing portion 5c integrally provided on the outer circumference of the flange portion 5b and pressing each wedge member 9A, 9B from the circumferential direction to release the wedge action, and a wall portion 5f integrally formed on the inner circumferential surface of the other axial end of the cylindrical portion 5a.

[0038] The cylindrical portion 5a is formed such that the outer diameter of its outer circumferential surface 5d is slightly smaller than the inner diameter of the inner circumferential surface 4g of the bearing cylinder 4d, allowing it to rotate within the bearing cylinder 4d, and the aforementioned annular wall portion 5f is integrally provided on the inner circumferential surface of the tip portion 5e.

[0039] This wall portion 5f has female spline teeth 5g formed on it, which are annular internal teeth having a root circle diameter slightly smaller than the inner diameter of the cylindrical portion 5a. These female spline teeth 5g are spline-coupled with male spline teeth formed on the outer circumference of a drive shaft (not shown) connected to the output shaft of an electric motor (not shown) by meshing from the axial direction.

[0040] The flange portion 5b is formed in a ring shape, with a pressing portion 5c provided on its outer circumference, and an arc-shaped groove 5h is formed on the radially opposite side of the pressing portion 5c. This arc-shaped groove 5h is formed in a position that overlaps with the arc-shaped elongated hole 11d of the guide plate 11, and both protruding ends 10a, 10a of the ring spring 10 are fitted into it from the axial direction.

[0041] Here, the offset outer circumference of the flange portion 5b is such that one side facing the cylindrical portion 5a abuts against the guide plate 11. The inner side of the flange portion 5b is such that the other side opposite to the cylindrical portion 5a abuts against the inner surface near the edge of the insertion hole 2a of the lid member 2. As a result, the flange portion 5b restricts the guide plate 11 and the pair of wedge members 9A and 9B from moving axially and coming loose.

[0042] As shown in Figures 1 and 2, the pressing portion 5c is integrally provided in an arc shape on the lower side of the flange portion 5b and is formed to protrude axially toward the eccentric space 8. The rotational driving force of the electric motor causes both circumferential end faces to push out the respective tip portions 9b, 9b of the pair of wedge members 9A and 9B in the circumferential direction, thereby releasing the wedge action.

[0043] Furthermore, as shown in Figures 1 and 2, the lid member 2 and the first rotating body 4 are assembled such that their respective outer circumferences are restricted in the axial direction by the connecting ring 12 to allow relative rotation to each other, while the internal second rotating body 6, the wedge members 9A and 9B, and the components of the guide plate 11 overlap in the axial direction. Before assembly, the connecting ring 12 is formed in a cylindrical shape with its outer circumference end 12a extending in the axial direction, as shown in Figure 1, and after assembly, the outer circumference end 12a is bent toward the radial center, as shown in Figure 2.

[0044] [Effects of this embodiment] First, to explain the basic operation of this embodiment, when the drive bush 5 rotates in either direction due to the rotational drive of the output shaft of the electric motor, the pressing portion 5c of the drive bush 5 presses the narrow tip of one of the pair of wedge members 9A and 9B in the circumferential direction. At this time, the ring spring 10 is slightly compressed, and the other wedge members 9A and 9B rotate slightly in the same direction by the amount of compression, causing the wedge members 9A and 9B to disengage and the wedge effect to disappear.

[0045] Subsequently, the guide plate 11 slides in the eccentric space between the outer circumferential surface 4f of the bearing cylinder 4d of the first rotating body 4 and the inner circumferential surface 7a of the metal bearing 7 of the second rotating body 6. This maintains a constant amount of eccentricity between the outer circumferential surface 4f and the inner circumferential surface 7a, causing the pair of wedge members 9A, 9B and the guide plate 11 to pivot along the circumference inside the eccentric space 8. As a result, the meshing portion between the outer teeth 6a of the second rotating body 6 and the inner teeth 4a of the first rotating body 4 moves along the circumference. When the meshing portion completes one rotation, the number of teeth on the outer teeth 6a is one or two fewer than the number of teeth on the inner teeth 4a, so the first rotating body 4 having the inner teeth 4a rotates by the difference in the number of teeth in the opposite direction to the rotation direction of the meshing portion. In other words, when the drive bush 5 is rotated, the first rotating body 4, along with the back arm 3, is decelerated at a large reduction ratio relative to the cover member 2 fixed to the cushion arm 2, and rotates in the opposite direction to the rotation direction of the drive bush 5.

[0046] As a result, the seat back rotates relative to the seat cushion. When the rotation of the drive bush 5 stops, the pair of wedge members 9A and 9B are wedge-shaped and locked between the outer surface 4f of the bearing cylinder 4d and the inner surface 7a of the metal bearing 7 by the biasing force of the ring spring 10.

[0047] The pair of wedge members 9A and 9B bite into the space between the outer surface 4f of the bearing cylinder 4d and the inner surface 7a of the metal bearing 7 when locked, suppressing play between the outer teeth 6a and the inner teeth 4a. The guide plate 11 facilitates smooth sliding between the outer surface 4f of the bearing cylinder 4d and the inner surface 7a of the metal bearing 7 when the biting is released. As a result, the pair of wedge members 9A and 9B and the guide plate 11 distribute their functions, allowing the seat back to rotate smoothly relative to the seat cushion.

[0048] Then, as the drive bush 5 is rotationally driven, each wedge member 9A, 9B rotates in the circumferential direction while sliding between the outer circumferential surface 4f of the bearing cylinder 4d and the inner circumferential surface 7a of the metal bearing 7. At this time, within the cross section passing through the axis of the device, each wedge member 9A, 9B moves slightly back and forth in the axial direction between the outer circumferential surface 4f and the inner circumferential surface 7a. During this drive, for example, as shown in Figure 7, if the metal bearing 7 or the like is tilted via the second rotating body 6, the wedge members 9A, 9B will tilt along the inclined surface of the outer circumferential side surface 9d, so that the lower end corner 7b of the inner circumferential surface 7a of the metal bearing 7 does not collide with the outer circumferential side surface 9d of the wedge members 9A, 9B.

[0049] In other words, in this embodiment, at least each outer peripheral side surface 9d of each wedge member 9A, 9B is formed as an inclined surface with a downward slope of a predetermined angle θ from one end surface 9f to the other end surface 9g. Therefore, when the metal bearing 7 tilts, the inner circumferential surface 7a tilts in a manner that follows the inclined surface of the outer peripheral side surface 9d. As a result, the metal bearing 7 avoids the lower end corner 7b of the inner circumferential surface 7a colliding with the outer peripheral side surface 9d of the wedge members 9A, 9B. This reduces the sliding resistance of each wedge member 9A, 9B during operation, thereby suppressing twisting, vibration, and abnormal noise.

[0050] The tilt during operation is the same even if the wedge members 9A and 9B themselves are tilted. In this case, the wedge members 9A and 9B tilt slightly with their upper edges 9h and 9j as pivot points. However, because this tilt follows the inclined surfaces of the outer circumference side surface 9d and the inner circumference side surface 9e, the lower edges 9i and 9k do not come into contact with the inner circumference surface 7a of the metal bearing 7 or the outer circumference surface 4f of the bearing cylinder 4. In other words, even in this case, contact between each lower edge 9i and 9k and the corners 7b of the inner circumference surface 7a of the metal bearing 7 or the corners of the outer circumference surface 4f of the bearing cylinder 4 is avoided.

[0051] Therefore, in this case as well, the sliding resistance of each wedge member 9A and 9B during operation can be reduced, thereby suppressing the occurrence of twisting, vibration, and abnormal noise.

[0052] Furthermore, in this embodiment, since the outer peripheral side surface 9d and inner peripheral side surface 9e of each wedge member 9A and 9B are simply formed as inclined surfaces along the axial direction, the processing work becomes easier. In other words, as a method for forming each wedge member 9A and 9B, there is no need to use conventional methods such as forging, and it is possible to process them using a general press forming machine, or in this embodiment, a precision press forming machine. In addition, the processing steps for each wedge member 9A and 9B mainly involve the aforementioned press forming, and do not require many other steps, and can be formed by, for example, a single punching process, thus significantly reducing the processing time compared to conventional methods. As a result, the processing efficiency of each wedge member 9A and 9B is improved and processing costs are reduced.

[0053] Furthermore, since the inclined surfaces of each outer peripheral side 9d and each inner peripheral side 9e are formed in an area of ​​70% or more of the overall width length, sufficient suppression of twisting, vibration, and noise caused by each inclined surface can be ensured.

[0054] The present invention is not limited to the configuration of the above embodiment. For example, the housing portion can be made to consist only of the housing hole 6b, excluding the metal bearing 7. Furthermore, the inclination angles θ of the outer peripheral side surface 9d and the inner peripheral side surface 9e can be made to be different from each other.

[0055] Furthermore, the seat reclining device of the present invention can be applied to vehicles other than cars, such as ships. [Explanation of Symbols]

[0056] 1...Cushion-side arm, 2...Lid member, 3...Back-side arm, 4...First rotating body, 4a...Internal teeth, 4b...Annular recess (one end face), 4d...Bearing cylinder, 5...Drive bush (drive member), 5a...Cylindrical part, 5b...Flange part, 5c...Pressing part, 5d...Outer circumference, 5e...Tip part, 5f...Wall part, 5g...Female spline teeth (internal teeth part), 6...Second rotating body, 6a...External teeth, 6b...Housing hole (housing part), 7...Metal bearing (housing part), 7a...Inner circumference, 8...Eccentric space, 9A, 9B...Wedge member, 9a...Base end, 9b...Tip, 9d...Outer circumference side, 9e...Inner circumference side, 9f...One end face, 9g...Other end face, 9h·9j...Upper edge, 9k·9i...Lower edge, 10...Ring spring (spring member), θ...Angle

Claims

1. A first rotating body having multiple internal teeth partially cut out from the axial direction on its annular inner surface, A second rotating body having an annular outer surface that meshes with the internal teeth of the first rotating body and has multiple external teeth with one or two fewer teeth than the internal teeth, A cylindrical bearing cylinder is provided on one end face in the axial direction of either the first or second rotating body, projecting toward the other rotating body. A circular housing is provided on either the first or second rotating body, into which the bearing cylinder is inserted, and which is formed coaxially with the central axis of the other rotating body. With the internal teeth and external teeth meshed, a circular eccentric space is formed between the outer circumferential surface of the bearing cylinder and the inner circumferential surface of the housing portion, A pair of wedge members, each with an arc shape, are arranged within the eccentric space, with their base ends facing each other from the circumferential direction. A biasing means for biasing the pair of wedge members in a direction that separates them from each other in the circumferential direction, A vehicle seat reclining device comprising a drive member inserted and positioned within the eccentric space, which presses and rotates the pair of wedge members in the circumferential direction, Each wedge member has an arc-shaped outer circumferential side surface that is radially opposed to the inner circumferential surface of the housing and is in contact with at least a portion of the inner circumferential surface of the housing, and an arc-shaped inner circumferential side surface that is radially opposed to the outer circumferential surface of the bearing cylinder, and also has one end surface that is perpendicular to each of the outer circumferential side surfaces and is located opposite to one end surface of the one rotating body in the axial direction, and the other end surface that is positioned opposite to one end surface of the one rotating body, A seat reclining device characterized in that at least each of the outer peripheral surfaces of the wedge member is formed in an inclined manner in a direction that increases the gap with the inner peripheral surface of the housing portion from one end face to the other end face.

2. A seat reclining device according to claim 1, The seat reclining device is characterized in that each inner circumferential side surface of each wedge member is in contact with at least a portion of the outer circumferential surface of the bearing cylinder, and is formed in an inclined manner in a direction that increases the gap with the bearing cylinder from one end face to the other end face.

3. A seat reclining device according to claim 1, Each outer peripheral surface of the aforementioned wedge member is formed into a sheared surface by punching using a precision press molding machine. A seat reclining device characterized in that the inclined surfaces on each outer peripheral side are formed in an area of ​​70% or more of the overall width and length.

4. A seat reclining device according to claim 2, Each inner circumferential surface of each wedge member is formed into a sheared surface by punching with a precision press molding machine. A seat reclining device characterized in that the inclined surfaces on each inner circumferential side surface are formed in an area of ​​70% or more of the overall width and length.

5. A seat reclining device according to claim 1, The seat reclining device is characterized in that each outer peripheral surface of the wedge member has a minute inclination of about 0.02 mm in the distance from the inner peripheral surface of the opposing housing portion, with respect to that surface.

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