JP2008272152A - Vehicle seat reclining device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent fracture by preventing the application of a large bending force to a lock tooth even if enlarging a forward-tilting load applied to a seat back. <P>SOLUTION: The lock tooth is formed with a first sliding outer circumferential face 10a at its face facing an outer circumferential side guide face 12a of a first guide projection 12A, when a load for turning a lid body 7 is applied to a machine frame 5, the first guide projection 12A and a shaft 11 receive the load, and the hardness of the first outer circumferential face 10a is set larger than that of the outer circumferential side guide face 12a; the lock tooth 10 is provided with two recesses 10g, when the load applied from the lock tooth 10 to the first guide projection 12A is enlarged, the outer circumferential guide face 12a is deformed and intrudes into the two recesses to form deformed projections 12g; and the direction of a reaction R<SB>12</SB>to the load which the deformed projection 12 receives from the lock tooth 10 faces closer to the central side of a cam 9 than a bending center P of the bending moment for fracturing the lock tooth 10. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a vehicle seat reclining device for fixing a seat back that is a backrest to a seat cushion that is a seating surface so that the angle can be adjusted, so that the seat back can withstand even when a large load is applied to the seat back. It is.

  As a vehicle seat reclining device, for example, as shown in FIG. 6, a machine frame attached to a base plate on the seat cushion side and a lid attached to an arm plate on the seat back side are relatively rotatable. The seat is configured to engage a lock tooth external gear attached to the machine frame with an internal gear formed on an inner peripheral surface of the lid body, thereby restricting relative rotation between the machine frame and the lid body, A configuration in which the back is held at a predetermined angular position is known.

  In order to fix the lock tooth, a shaft portion and a pair of guide portions project from the machine gear in the vicinity of the internal gear, and the lock tooth has a concave bearing that swingably engages with the shaft portion. And a convex sliding surface coaxial with the bearing surface and in sliding contact with the guide surfaces of the pair of guide portions. Further, a cam for pressing the lock tooth outward to engage the external gear with the internal gear is provided at the center of the internal gear.

  In the vehicle seat reclining device configured as described above, when a vehicle collides forward, a load is applied in a direction in which the seat back is moved forward, and this load is applied to the lock tooth via the meshing portion between the internal gear and the external gear. Act on. At this time, since the lock tooth is supported by the shaft portion and one guide portion, the rotation of the lid with respect to the machine frame is restricted, and the seat back does not rotate even when a load is applied.

  On the other hand, when a large load is applied to the seat back, there is a limit to receiving the load with a small shaft part, so in order to increase the load received with one guide part, the contact area with one guide part Need to be larger. However, when the load received by one guide portion is increased, the reaction force applied to the lock tooth from one guide portion also increases, and a large bending stress acts on the lock tooth due to the reaction force, and the lock tooth may break at an early stage. When the lock tooth is broken, only the shaft portion and the cam support the lock tooth, so that the lock tooth is inclined and the engagement between the internal gear and the external gear is deteriorated. Accordingly, the strength and stability of the seat reclining device cannot be improved.

For this reason, for example, an invention described in Patent Document 1 is known as a conventional vehicle seat reclining device that prevents the lock tooth from breaking. According to the present invention, a sliding outer peripheral surface is formed on the opposite surface of the lock tooth that is in the vicinity of the end opposite to the external gear and faces the outer peripheral guide surface of one guide portion, and the lock tooth is formed on the one guide portion. When a large load is applied, a backup surface that receives the load is provided on one guide portion, and a contact surface is formed on the lock tooth with a gap between the backup surface and the rotating member is rotated with respect to the base member. In the vehicle seat reclining device configured to receive the load by the one guide portion and the shaft portion when the load to be acted is applied, while forming a step portion between the outer peripheral side guide surface and the backup surface, In the lock tooth, a projecting portion facing the step portion is formed between the sliding outer peripheral surface and the contact surface, and the direction of the reaction force received from the step portion when the projecting portion abuts on the step portion is determined. , Rocks It is obtained by set toward the center side of the cam than the bending center of the bending moment to break the scan.
JP 2006-246988 A

  However, in the past, the belt anchor that supported the force applied to the seat belt was the center pillar.In recent years, however, an increasing number of vehicles are changing from the center pillar to the seat back. Inertial force due to body weight is applied in the direction of moving the seat back forward, and a larger load than before is applied to the seat back. For this reason, the vehicle seat reclining device is required to be able to withstand a larger load than before.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a vehicle seat reclining device with further increased strength.

  According to a first aspect of the present invention, there is provided a base member coupled to one of a seat cushion and a seat back fixed to the seat cushion so as to be rotatable, and a base member coupled to the other and the base member. A rotating member having an internal gear on the inner peripheral surface and an external gear that can mesh with the internal gear, and the external gear engages and disengages with the internal gear. A lock tooth capable of swinging in a direction, a center side guide surface for swinging the lock tooth along an arcuate track, and a shaft portion integrally formed with the base member, and the lock tooth swinging along the arcuate track A pair of guide portions integrally formed with the base member in the vicinity of both ends of the circular arc track and an outer peripheral guide surface for moving the outer peripheral gear to the internal gear by pressing the lock tooth. A cam to be engaged with the outer peripheral guide surface of the lock tooth on the opposite surface of the one of the guide portions facing the outer peripheral guide surface. A sliding outer peripheral surface that moves, a backup surface that receives a load when the load applied from the lock tooth is large on the one guide portion, and a contact surface that contacts the lock tooth through a gap between the backup surface In the vehicle seat reclining device, the sliding outer periphery receives the load by the one guide portion and the shaft portion when a load that rotates the rotating member acts on the base member. When the hardness of the surface is set to be larger than that of the outer peripheral guide surface and the load applied from the lock tooth to the one guide portion increases, One or more concave portions that form a deformed convex portion by being formed are formed on the sliding outer peripheral surface, and the direction of the reaction force against the load that the deformed convex portion receives from the lock tooth is a bending moment that breaks the lock tooth. It is characterized in that it faces the center side of the cam with respect to the bending center.

  According to the present invention, when a large load is applied from the lock tooth to one of the guide portions, the outer peripheral guide surface is deformed because the hardness of the sliding outer peripheral surface is larger than that of the outer peripheral guide surface. Intrudes and forms a deformed convex part. Then, when a load is applied from the concave portion of the lock tooth to the deformed convex portion, the reaction force is applied from the surface of the deformed convex portion in a direction perpendicular to the surface, and a bending moment is applied to the lock tooth by this reaction force. This bending moment acts as an offset bending moment that cancels the bending moment in the direction of breaking the lock tooth. Therefore, the bending moment in the direction of breaking the lock tooth is reduced, and the break of the lock tooth is avoided.

  According to a second aspect of the present invention, in the vehicle seat reclining device according to the first aspect, a step portion is formed between the outer peripheral guide surface and the backup surface in the one guide portion, while the lock tooth is formed. A projecting portion facing the step portion is formed between the sliding outer peripheral surface and the contact surface, and a direction of a reaction force received from the step portion when the projecting portion contacts the step portion. However, it is characterized in that it is directed to the center side of the cam from the bending center of the bending moment that breaks the lock tooth.

  According to the present invention, when the lock tooth moves to the one guide portion side under a large load, the protruding portion of the lock tooth comes into contact with the step portion of the one guide portion. At this time, since the direction of the reaction force received from the step portion is set to be closer to the center of the cam than the bending center of the bending moment that breaks the lock tooth, this reaction force also cancels the bending moment in the direction of breaking the lock tooth. Acts as an offset bending moment. Therefore, the bending moment in the direction of breaking the lock tooth is further reduced, and the break of the lock tooth is more reliably avoided.

  According to the vehicle seat reclining device of the first aspect, the hardness of the sliding outer peripheral surface is set to be larger than that of the outer peripheral guide surface, and the outer peripheral guide surface is deformed when the load applied from the lock tooth to the one guide portion increases. Since one or two or more concave portions forming the deformed convex portion by forming are formed, the direction of the reaction force with respect to the load that the deformed convex portion receives from the lock tooth is greater than the bending center of the bending moment that breaks the lock tooth. The bending moment applied to the lock tooth due to this reaction force acts as an offset bending moment that cancels the lock tooth in the direction that breaks the lock tooth. Is done. As a result, the load received by one of the guide portions can be increased, and the strength and stability of the seat reclining device can be stabilized and improved.

  According to the vehicle seat reclining device of the second aspect, the step portion is formed between the outer peripheral side guide surface and the backup surface of the one guide portion, while the lock tooth slides the protruding portion facing the step portion. It is formed between the dynamic outer peripheral surface and the contact surface, and the direction of the reaction force received from the step when the projecting portion comes into contact with the step is greater than the bending center of the bending moment that breaks the lock tooth. Because it faces toward the center, when the lock tooth protrusion comes into contact with the stepped part of one guide under a large load, the reaction force also acts as a canceling bending moment that cancels the bending moment in the direction of breaking the lock tooth. To do. Therefore, the bending moment in the direction of breaking the lock tooth is further reduced, and the break of the lock tooth is more reliably avoided.

  Hereinafter, embodiments of a vehicle seat reclining device according to the present invention will be described.

  As shown in FIG. 6, a seat cushion 2 that is a sitting portion is provided, and a seat back 3 is attached to the seat cushion 2 so as to be rotatable in the front-rear direction of the vehicle. A machine frame (base member) 5 is coupled to the seat cushion 2 via a base plate 4, while a lid (rotating member) 7 (not shown) is coupled to the seat back 3 via an arm plate 6. ing. A spring (not shown) that biases the seat back 3 toward the left side that is the front of the vehicle is provided with respect to the seat cushion 2.

  The machine casing 5 and the lid body 7 constitute a vehicle seat reclining device 1 shown in FIGS. The vehicle seat reclining device 1 will be described below. As shown in FIG. 1, the machine frame 5 has a circular recess formed by half-cutting the inside of the disk by pressing, while the lid 7 has a circular recess formed in the same manner by half-cutting the inside of the disk by pressing. An internal gear 7a is formed on the inner peripheral surface of the circular recess. A lid 7 is fitted into the circular recess of the machine frame 5 so as to be coaxial and relatively rotatable. As shown in FIG. 2, the outer periphery of the lid body 7 and the machine frame 5 is sandwiched between the ring-shaped holders 8 so that the lid body 7 and the machine frame 5 are relatively rotated without being separated in the axial direction. Held possible. Between the machine frame 5 and the lid body 7 in the axial direction, a rotary cam 9 is arranged in the center, and a pair of swingable lock teeth 10 are arranged in the vertical position across the cam 9.

  A substantially cylindrical shaft portion 11 having a center side guide surface 11a is integrally formed with the machine frame 5 on the inner peripheral side of the arc track for guiding the lock tooth 10 so as to be swingable along the arc track. A part of the lock tooth 10 is cut into a substantially circular shape to form a bearing surface 10c. On the other hand, first and second guide projections 12A and 12B are provided on the outer peripheral side in the vicinity of both ends of the arc track for swingably guiding the lock tooth 10 along the arc track. The first and second guide protrusions 12A and 12B are formed with first and second outer peripheral guide surfaces 12a and 12b. The lock tooth 10 is formed with first and second sliding outer circumferential surfaces 10a and 10b that slide with the first and second outer circumferential guide surfaces 12a and 12b. Since the lock tooth 10 swings along the circular arc track, the first and second outer peripheral guide surfaces 12 a and 12 b and the first and second sliding outer peripheral surfaces 10 a and 10 b are coaxial with respect to the center of the shaft portion 11. The arc shape is formed. An external gear 10d that can mesh with the internal gear 7a is formed on the surface of the lock tooth 10 that swings along the arcuate track and faces the internal gear 7a.

  The cam 9 is provided to press the lock tooth 10 having the external gear 10d engaged with and disengaged from the internal gear 7a toward the internal gear 7a. By rotating the cam 9 counterclockwise about the center hole 9e of the cam 9, the pair of lock teeth 10 are pressed radially outward with the cam 9 as the center, and the external gear 10d is turned into the internal gear 7a. It is possible to release the meshing by engaging with each other or rotating it clockwise. By meshing the external gear 10d with the internal gear 7a, the rotation of the lid 7 with respect to the machine frame 5 is restricted, and the seat back 3 is held at a predetermined angular position with respect to the seat cushion 2.

  The cam 9 has a lock cam surface 9a for swinging the lock tooth 10 clockwise about the shaft portion 11 to mesh the external gear 10d with the internal gear 7a, and the lock tooth 10 counteracting the shaft portion 11 about the shaft portion 11. An unlocking cam surface 9b is formed for swinging clockwise and pulling the external gear 10d away from the internal gear 7a. The cam 9 is formed with a sliding outer peripheral surface 9c that restricts the movement of the cam 9 in the left-right direction in FIG. The sliding outer peripheral surface 9c is formed in an arc shape with the center hole 9e of the cam 9 as the center. The sliding outer peripheral surface 9c is always in sliding contact with the sliding contact surface 12d formed on the first guide convex portion 12A.

  In order to constantly urge the external gear 10d of the lock tooth 10 to mesh with the internal gear 7a, a lock spring 19 is provided that urges the cam 9 to rotate counterclockwise. The base end of the lock spring 19 is attached via a semi-cylindrical convex portion 14 formed integrally with the machine frame 5, and the distal end is attached to a locking portion 9 d formed on the outer peripheral surface of the cam 9. It is locked.

  When a forward load is applied to the back seat 3 of FIG. 6, the relative rotational force of the lid body 7 with respect to the machine frame 5 is applied to the lock tooth 10 via the meshing portion of the internal gear 7a and the external gear 10d. The lock tooth 10 is about to rotate clockwise in FIG. 1, but is supported by the cam 9, the shaft portion 11, and the first guide convex portion 12A. The lock tooth 10 is formed with an abutment surface 10f in the vicinity of the end opposite to the external gear 10d. On the other hand, a backup surface 12e for supporting the contact surface 10f is formed on the first guide convex portion (one guide convex portion) 12A through the gap 13 with the contact surface 10f. This is because the shaft 11 and the first outer peripheral guide surface 12a receive a load applied to the lock tooth 10, and when the load further increases and the deformation progresses, the contact surface 10f contacts the backup surface 12e and is supported. It was made to do. The contact surface 10f and the backup surface 12e are formed along a coaxial arc centering on the center of the shaft portion 11.

A step portion 12f is formed between the first outer peripheral guide surface 12a and the backup surface 12e, and the contact surface 10f is brought into contact with the step portion 12f before contacting the backup surface 12e. The lock tooth 10 has a protrusion 10e. The direction of the reaction force R _{13 in} FIG. 3 that the protrusion 10e receives from the step 12f when the protrusion 10e abuts on the step 12f is greater than the bending center P of the bending moment that causes the lock tooth 10 to break. 9 is set to be on the center side. Here, the bending moment that breaks the lock tooth 10 applies a large load in the direction in which the seat back is moved forward, and this load is applied from the lid 7 to the lock tooth 10 via the meshing portion of the internal gear 7a and the external gear 10d. act, the lock tooth 10 to be supported by the first guide portion projection 12A and the shaft portion 11, the reaction force R ₁₁ applied to the lock tooth 10 from the first guide projection 12A is also increased by reaction force R ₁₁ This is because a large counterclockwise bending stress acts on the lock tooth 10 around the bending center P.

In addition, by hardening the lock tooth 10, the hardness of the first sliding outer peripheral surface 10a is set to be greater than the hardness of the outer first peripheral guide surface 12a. When the load applied from the lock tooth 10 to the first guide convex portion 12A is increased, the first outer peripheral guide surface 12a is deformed and enters, so that the two concave portions 10g forming the deformed convex portions on the first outer peripheral guide surface 12a are formed. Is formed. Resulting reaction force R _7, R ₉ in Figure 5 these variations projections formed will be described later with respect to a load applied from the lock tooth 10, the bending moment direction of the reaction force R _7, R ₉ is to break the lock tooth 10 This is the center side of the cam 9 with respect to the bending center P, and a canceling bending moment that cancels the bending moment in the direction of breaking the lock tooth 10 is generated in the lock tooth 10.

  The vehicle seat reclining device 1 configured as described above is disposed on both sides of the seat cushion 2 in the width direction, and as shown in FIG. 2, operation shafts individually provided on the left and right vehicle seat reclining devices 1. 15 are connected via a shaft 16. That is, the operation shaft 15 is press-fitted and fixed in the center hole 9 e of the cam 9, and the operation shaft 15 includes a serration 15 a formed at one end of the operation shaft 15 and a serration 16 a formed on the cylindrical shaft 16. It is coupled to the shaft 16 via

  On the other hand, a serration 15b is formed at the other end of the operating shaft 15 as shown in FIG. 2, the serration 15b protrudes outward from the base plate 4, and the operating lever 20 is placed on the serration 15b as shown in FIG. The operation lever 20 is provided with an operation knob 21.

  Next, the operation of the vehicle seat reclining device 1 will be described.

  In a state where the vehicle seat reclining device 1 is assembled to the seat, the cam 9 is normally rotated counterclockwise by the urging force of the lock spring 19 as shown in FIG. The lock tooth 10 is pressed by 9a, the lock tooth 10 is guided by the shaft portion 11 and the first and second outer peripheral guide surfaces 12a and 12b, and swings clockwise around the shaft portion 11 so that the external gear 10d is covered. It is in a state of meshing with the internal gear 7 a of the body 7. That is, the rotation of the seat back 3 is restricted.

  Next, when the operation knob 21 is operated and the operation shaft 15 is rotated clockwise in FIG. 6 against the urging force of the lock spring 19, the engagement between the lock cam surface 9 a of the cam 9 and the lock tooth 10 is performed. While being released, the unlocking cam surface 9b presses the lock tooth 10 in the opposite direction. Therefore, the lock tooth 10 swings counterclockwise about the shaft portion 11, the meshing of the external gear 10d and the internal gear 7a is released, and the lock tooth 10 is unlocked, and the arm to which the lid body 7 is attached. The plate 6 and the seat back 3 are rotated forward by a biasing force of a spring (not shown).

  When the seat back 3 is rotated in the backward direction against the urging force of a spring (not shown) and released from the operation knob 21 at the desired angular position of the seat back 3, the cam is urged by the urging force of the lock spring 19. 9 rotates counterclockwise, and the lock cam surface 9 a presses the lock tooth 10 clockwise about the shaft portion 11. For this reason, the external gear 10d of the lock tooth 10 meshes with the internal gear 7a to return to the locked state.

  Next, the operation when a forward load is applied to the seat back 3 in FIG. 6 will be described.

First, FIG. 4 shows an operation when the two concave portions 10g are not formed on the first outer peripheral guide surface 12a as in the present invention. As shown in the figure, when the lid 7 tries to rotate in the clockwise direction relative to the machine frame 5 as indicated by the arrow, the rotational force is transmitted through the meshing portion of the internal gear 7a and the external gear 10d. Therefore, the lock tooth 10 tends to rotate clockwise in FIG. 4 and the first sliding outer peripheral surface 10a is pressed against the first outer peripheral guide surface 12a. For this reason, the load F1 acts in the tangential direction of the circle centering on the center of the cam 9. This load F ₁ is decomposed into a load F _{2 in} a direction perpendicular to the contact surface and a load F _{3 in} a direction parallel to the contact surface, and a reaction force R ₁ , as a reaction force between the load F ₂ and the load F ₃ , R ₂ is generated. Among these, the reaction force R _{1 in} a direction perpendicular to the contact surface acts on the lock tooth 10 and acts as a bending moment that bends the lock tooth 10 counterclockwise. Therefore, when the reaction force increases, the lock tooth 10 may be broken by this bending moment.

  Next, the effect | action of this invention which formed the two recessed parts 10g in the 1st outer peripheral side guide surface 12a is demonstrated based on FIG. In this case, when the clockwise rotating force in FIG. 3 acts on the lock tooth 10, the lock tooth 10 is supported by the cam 9, the shaft portion 11, and the first guide convex portion 12A. When the forward load applied to the seat back 3 is increased, the contact portion of the lock tooth 10, the shaft portion 11, and the first guide convex portion 12A is deformed as shown in FIG. Since the hardness of the first sliding outer peripheral surface 10a is greater than that of the first outer peripheral guide surface 12a, the first outer peripheral guide surface 12a is deformed and enters the two recesses 10g of the lock tooth 10 to form the first outer peripheral guide surface. The deformation convex part 12g is formed in 12a. Here, in order to make the rate of receiving the load at the contact portion between the lock tooth 10 and the first guide convex portion 12A larger than the rate of receiving the load at the contact portion between the lock tooth 10 and the shaft portion 11, The contact area between the sliding outer circumferential surface 10a and the first outer circumferential guide surface 12a is set to be large. For this reason, the displacement amount of the first outer circumferential guide surface 12a crushed by the first sliding outer circumferential surface 10a is as follows. Although it becomes large, since a part of the deformed first outer peripheral side guide surface 12a enters the recess 10g, the amount of displacement can be small.

When the deformed convex portion 12g is formed, the lock tooth 10 is further rotated in the clockwise direction in FIG. 3, and the first sliding outer peripheral surface 10a is pressed against the first outer peripheral guide surface 12a. In other words, loads F ₄ and F ₇ are applied in the tangential direction of the circle centered on the center of the cam 9 on both sides of the two convex portions 12g of the first outer peripheral guide surface 12a. The load F _4, F ₇ is decomposed into a contact surface and the load F ₆ perpendicular to the direction of the load F _5, F ₈ the contact surface parallel to the direction, F _9, the load F _5, F ₈ Reaction forces R ₃ and R ₅ are generated as reaction forces, and reaction forces R ₄ and R ₆ are generated as reaction forces of the loads F ₆ and F ₉ . Among these, the reaction forces R ₃ and R _{5 in the} direction perpendicular to the contact surface act on the lock tooth 10 to be a bending moment that bends the lock tooth 10 counterclockwise. The reaction forces R ₃ and R ₅ correspond to the reaction force R ₁ in FIG.

Next, at the positions of the two convex portions 12g, loads F ₁₀ and F ₁₃ act in the tangential direction of the circle centered on the center of the cam 9. The load F _10, F ₁₃ is decomposed into a contact surface perpendicular to the direction of the load F _11, F ₁₄ and the load F ₁₂ of the contact surface in a direction parallel, F _15, the load F _11, F ₁₄ Reaction forces R ₇ and R ₉ are generated as reaction forces, and reaction forces R ₈ and R ₁₀ are generated as reaction forces of the loads F ₁₂ and F ₁₅ . Of these, the directions of the reaction forces R ₇ and R _{9 in} the direction perpendicular to the contact surface act on the lock tooth 10 toward the center side of the cam 9 with respect to the bending center P of the bending moment, so that the lock tooth 10 moves clockwise. Bending moment to bend. In addition, since the surface on the opposite side of the two convex portions 12g is substantially parallel to the tangent of the circle centered on the center of the cam 9, almost no reaction force is generated. Further, the reaction force acting on the tip portions of the two convex portions 12g is substantially the same as the directions of the reaction forces R ₃ and R ₅ , but since the area is small, there is no problem even if omitted here.

The resultant force of reaction forces R ₃ and R ₅ in FIG. 5 is represented as reaction force R _{11 in} FIG. 3, and the resultant force of reaction forces R ₇ and R ₉ in FIG. 5 is represented as reaction force R _{12 in} FIG.

In summary, the reaction force R ₁₁ perpendicular to the first outer peripheral guide surface 12a and the reaction force R ₁₂ perpendicular to the surfaces of the two convex portions 12g act on the lock tooth 10 as shown in FIG. Will do. Due to the reaction force R ₁₁ , a bending moment in the counterclockwise direction around the bending center P of the lock tooth 10 acts on the lock tooth 10. On the other hand, a counterclockwise bending moment about the bending center P of the lock tooth 10 acts by the reaction force R ₁₂ , and an offset bending moment that cancels the bending moment in the direction of breaking the lock tooth 10 acts on the lock tooth 10. It will be. Therefore, the counterclockwise bending moment in the direction of breaking the lock tooth 10 is reduced, and the break of the lock tooth 10 is avoided.

When the forward load applied to the seat back 3 is further increased, the protruding portion 10e of the lock tooth 10 comes into contact with the step portion 12f as shown in FIG. 3 before the gap 13 disappears and the contact surface 10f comes into contact with the backup surface 12e. . At this time, it receives a reaction force R ₁₃ protrusions 10e from the stepped portion 12f. The direction of the reaction force R ₁₃ is directed toward the center of the cam 9 with respect to the bending center P of the bending moment that breaks the lock tooth 10 due to the reaction force R _11. It acts as a canceling bending moment that cancels the moment. Therefore, the bending moment in the direction of breaking the lock tooth 10 due to the reaction force R ₁₁ is reduced, and the break of the lock tooth 10 before the abutment surface 10f of the lock tooth 10 abuts against the backup surface 12e is avoided.

That is, in the previous stage of projecting portions 10e as described above comes into contact with the step portion 12f, the direction of the bending moment due to the reaction force R ₁₁ acting to lock tooth 10 from the first outer peripheral guide surface 12a to break the lock tooth 10 is acting to have, but the reaction force R ₁₂ is caused by the presence of the deformable protrusion 12g of the first outer peripheral guide surface 12a formed enters into the recess 10g of the lock tooth 10, bending moment bending moment offset caused by reaction force R ₁₂ act as, then, the projecting portion 10e of the lock tooth 10 abuts against the step portion 12f, further reaction force R generated by the ₁₃ bending moment from the step portion 12f acts as offset bending moment which is newly added. Therefore, the breakage of the lock tooth 10 is reliably avoided. Therefore, the contact area between the first sliding outer peripheral surface 10a and the first outer peripheral guide surface 12a can be increased, and the load received by the first guide convex portion 12A can be increased. As a result, the displacement of the lock tooth 10 can be reduced, and the strength can be stabilized and improved.

  The shape of the concave portion is not limited to the rounded triangular shape of the present embodiment as long as a canceling bending moment is generated. In addition, while the step portion is formed on one guide portion, the lock tooth has the protruding portion facing the step portion, but a configuration may be adopted in which these are not provided. Furthermore, the present embodiment shows a case where the cover body is configured to rotate clockwise relative to the machine frame when a load is applied in a direction in which the seat back is moved forward. In addition, when a load is applied in the direction in which the seat back is moved backward, the lid body may be rotated in the clockwise direction relative to the machine frame.

BRIEF DESCRIPTION OF THE DRAWINGS The block diagram which shows the vehicle seat reclining apparatus partly broken (embodiment). Side surface sectional drawing of a vehicle seat reclining device (embodiment). Explanatory drawing of operation when a large load in the forward direction is applied to the seat back (embodiment). Action | operation explanatory drawing when not forming two recessed parts in lock tooth. Explanatory drawing which shows the relationship of the load between a 1st guide convex part and a lock tooth when the big load of a forward tilt direction is added to the seat back of the vehicle seat reclining apparatus which concerns on this invention (embodiment). 1 is a configuration diagram of a vehicle seat (embodiment).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Vehicle seat reclining device 2 ... Seat cushion 3 ... Seat back 5 ... Machine frame (base member)
7: Lid (rotating member)
7a ... Internal gear 9 ... Cam 10 ... Lock tooth 10a ... First sliding outer peripheral surface 10c ... Bearing surface 10d ... External gear 10e ... Protruding portion 10f ... Abutting surface 10g ... Recessed portion 11 ... Shaft portion 11a ... Center side guide surface 12A ... 1st guide convex part (guide part)
12B ... 2nd guide convex part (guide part)
12a ... 1st outer peripheral side guide surface (outer peripheral side guide surface)
12e ... Backup surface 12f ... Step part 12g ... Deformed convex part 13 ... Gap

Claims (2)

A base member coupled to one of a seat cushion and a seat back fixed to the seat cushion so as to be rotatable, and a base member coupled to the other and rotatable relative to the base member in the circumferential direction. And a rotation member having an internal gear on the inner peripheral surface, and a lock tooth having an external gear that can mesh with the internal gear and swingable in a direction in which the external gear engages and disengages with the internal gear. A shaft portion integrally formed with the base member, and an outer peripheral guide surface for swinging the lock tooth along the arcuate track. And a pair of guide portions integrally formed with the base member in the vicinity of both ends of the circular arc track, and a cam that presses the lock tooth to mesh the external gear with the internal gear.
A sliding outer peripheral surface that slides with the outer peripheral guide surface is provided on the opposite surface of the one of the guide portions facing the outer peripheral guide surface in the vicinity of the end of the lock tooth opposite to the outer gear. Forming a backup surface that receives a load when the load applied from the lock tooth is large on the one guide portion, and forming a contact surface on the lock tooth via a gap between the backup surface, and the base member In the vehicle seat reclining device that receives the load by the one guide portion and the shaft portion when a load for rotating the rotating member is applied to
When the hardness of the sliding outer peripheral surface is set to be larger than that of the outer peripheral guide surface, and the load applied from the lock tooth to the one guide portion increases, the outer peripheral guide surface is deformed and enters to form a deformed convex portion. One or more recesses are formed on the sliding outer peripheral surface, and the direction of the reaction force with respect to the load that the deforming projection receives from the lock tooth is closer to the center of the cam than the bending center of the bending moment that breaks the lock tooth. A vehicle seat reclining device. The vehicle seat reclining device according to claim 1,
The one guide portion is formed with a step portion between the outer peripheral guide surface and the backup surface, while the lock tooth has a protruding portion facing the step portion with the sliding outer peripheral surface and the contact surface. The direction of the reaction force received from the step when the projecting portion abuts on the step is directed toward the center of the cam from the bending center of the bending moment that breaks the lock tooth. A vehicle seat reclining device.

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