JPH11182587A - Seat back inclination regulating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a seat back inclination regulation device which is capable of continuously regulating the inclination to a desired angle, capable of simultaneously and freely regulating the falling direction and the erecting direction, excellent in the operability, and simple in structure. SOLUTION: Either of an inner race 1 or an outer race 2 to constitute a clutch 30 is fixed to a seat fixing frame 31, and the other ring is fixed to a seat back fixing frame 32. The clutch 30 is provided with the inner race 1 and the outer race 2, a locking means to lock the rotation between the inner and outer races 1, 2 in the forward and reverse directions through the friction contact, and a lock releasing means 13. The locking means 12 comprises a cam surface 6 and a rolling element 3 provided on the inner race 1. The lock releasing means 13 comprises a holder 4 to hold the rolling element 3, and a holder fixing groove 7 provided on the inner race 1, and is operated by an operation member 16 having a lever.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for adjusting a tilt of a seat back of a reclining seat in an automobile or other equipment.

[0002]

2. Description of the Related Art In a manual reclining seat of an automobile or the like, a backrest tilt adjusting device using a ratchet mechanism is mainly used. In addition, a planetary gear type is also partially used.

[0003]

However, in the case of using the ratchet mechanism, the backrest angle can be adjusted only in steps, and the usability is poor. Also, defeat the backrest,
When returning, an abnormal sound may be emitted when the ratchet is incompletely engaged. The planetary gear type can be adjusted steplessly, but cannot be operated with one touch, and has a problem that the structure is complicated and the cost is high.
In addition, this type of conventional back-tilt adjusting device generally requires a lever operation or the like to be performed again and then a return operation when the device is tilted too much or raised too much, which is inferior in operability. There is a problem.

SUMMARY OF THE INVENTION The present invention provides a seat back tilt adjusting apparatus having a simple structure, in which the tilt can be adjusted to a desired angle steplessly, the tilting direction and the raising direction can be simultaneously adjusted freely, the operability is good, and the configuration is simple. The purpose is to: Another object of the present invention is to provide smooth operability.

[0005]

According to the present invention, there is provided an apparatus for adjusting the inclination of a seat backrest in which one of an inner ring and an outer ring constituting a clutch is fixed to a seat fixing frame and the other is fixed to a backrest fixing frame. The clutch includes the inner ring and the outer ring that are rotatable in opposite directions.
Lock means for normally locking the forward and reverse rotation between the inner and outer wheels in frictional contact, and unlocking means for releasing the lock of the lock means so that the inner and outer wheels can rotate in both forward and reverse directions by applying a predetermined external force. , An operating member for applying the external force. According to this configuration, the rotation of the inner race and the outer race is locked so that relative rotation between the inner race and the outer race cannot be performed at all times, that is, the rotation is prevented. Is added, the lock of the lock means is released, and the rotation of the inner ring and the outer ring in both the forward and reverse directions becomes possible. Therefore, in the unlocked state, the backrest can be freely adjusted in both the falling direction and the raising direction. Further, since the rotation is locked by frictional contact, the inclination can be adjusted steplessly.

In the above configuration, the locking means and the unlocking means may have the following configuration. That is, the locking means is provided on one of the outer diameter surface of the inner ring and the inner diameter surface of the outer ring, and on the other of the outer diameter surface of the inner ring and the inner diameter surface of the outer ring. A plurality of cam surfaces facing the surface, and a plurality of rolling elements interposed between the circumferential raceway surface and each cam surface. The cam surface is
A central portion is formed so as to be deep and shallow on both sides in the circumferential direction, and the rolling element is biased in any direction from the central position to frictionally contact the rolling element to lock relative rotation of the inner and outer rings. I do. A lock release means, a retainer having a pocket for holding each rolling element in a position-regulated state,
Guide means for fixing the retainer to the side wheel on which the cam surface is formed so that the rolling element is positioned at the center of the cam surface when a predetermined external force is applied. In the case of this configuration, normally, when the relative rotation in any direction slightly occurs between the inner ring and the outer ring, the rolling element moves the cam surface from the center position to a shallow position with this rotation, and the cam surface Frictional contact with the outer raceway surface to prevent further relative rotation between the inner and outer rings. If the relative rotation occurs in the opposite direction, the rolling element moves from the center position of the cam surface to a position deviated in the opposite direction, thereby preventing further relative rotation of the inner and outer rings. Therefore, the backrest is held at the adjusted angle. When a predetermined external force is applied to the retainer by the operation means, the retainer is slightly moved by being guided by the guide means, and the rolling element held by the retainer is positioned at the deepest central position of the cam surface. Therefore, the locking of the rotation in both directions is simultaneously released. As described above, since the locking is performed through the rolling elements, smooth operability is obtained.

Further, in this configuration, the guide means is provided on the other of the retainer fixing groove provided on one of the cam ring forming side wheel and the retainer of the inner ring and the outer ring. It is good also as what consists of an engagement projection. The retainer fixing groove and the engaging projection are engaged with each other in a loose state when the external force is not applied, and are closely engaged with each other when the external force is applied. An elastic member that applies frictional force is provided between the inner race and the outer race on which the circumferential raceway surface is formed and the retainer. In the case of this configuration, the retainer fixing groove and the engaging projection are normally engaged in a loose state, and the relative rotation between the retainer and the cam surface side wheel is possible in this loose range. Therefore, the function of holding the rolling element at the center position of the cam surface by the retainer does not occur, and the relative rotation between the inner and outer rings in both directions is locked by the frictional contact of the rolling element as described above. When a predetermined external force is applied to the retainer, the retainer fixing groove and the engaging protrusion are closely engaged with each other, and the retainer is restrained by the cam surface side wheel, and the held rolling element is moved to the center position of the cam surface. To hold. Therefore, relative rotation in both directions between the inner and outer wheels becomes possible. The elastic body causes the retainer to rotate by rotation of the circumferential raceway surface side wheel so that the rolling element moves to a position shallow on the cam surface when the lock state is removed again after the release of the lock and the external force is removed. This ensures that locking occurs.

Further, in this configuration, the inner ring is fixed to the seat fixing frame, an outer ring is fixed to the backrest fixing frame, and the operating member is attached to a main shaft provided on the seat fixing frame at a position concentric with the inner ring. The retainer fixing groove and the engagement protrusion are axially engaged with each other, and the operating member and the retainer retain the axial force that is the external force as the operating member rotates. An operating cam surface for operating the vessel may be provided.

The lock means and the lock release means may have the following configuration. That is, the locking means is provided on one of the outer diameter surface of the inner ring and the inner diameter surface of the outer ring and is capable of swinging in the circumferential direction of the inner and outer rings, and the outer diameter surface of the inner ring and the inner diameter of the outer ring. It shall be a cylindrical sprag contact surface provided on the other of the surfaces. The sprags are in a non-contact state with the sprag contact surface at a neutral angle to allow relative rotation of the inner and outer rings, and by tilting in any direction in the normal and reverse directions, frictional contact with the sprag contact surface and relative rotation between the inner and outer rings. Shall be locked. The unlocking means switches between a state in which the sprag is held at a neutral angle and a state in which the sprag is swingable. In the case of this configuration, when the angle of the sprag is not held by the unlocking means, the sprag can swing in both forward and reverse directions. When relative rotation occurs between the inner and outer rings, the sprags are tilted with the rotation and frictionally contact the sprag contact surface of the inner or outer ring. Therefore, the relative rotation between the inner and outer wheels is locked. Therefore, the backrest is held at the adjusted angle. When the sprags are held at the neutral angle by the unlocking means, the sprags are brought into a non-contact state with the sprag contact surface, and the inner and outer races are allowed to rotate in any forward or reverse direction.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. 2, the seat fixing frame 31 is fixed to the seat 33 of FIG. 1, and the backrest fixing frame 32 is fixed to the backrest 34, respectively. In this state, when the lever 16a of the operation member 16 of the clutch 30 is pulled up to lower the backrest 34 and the lever 16a is returned at that position, the backrest 34 is fixed at that position. The backrest 34 is always urged by a spring member 35 in a direction in which the backrest 34 rises. Although the spring member 35 is shown in the form of a coil spring, a mainspring is actually used in many cases near the center of rotation of the backrest fixed frame, that is, near the clutch. Both the seat fixing frame 31 and the backrest fixing frame 32 are made of arm-shaped plate members.

Referring to FIG. 3, the configuration of each unit will be described. The clutch 30 mainly includes the inner race 1, the outer race 2, the rolling elements 3, the retainer 4, the elastic body 5, the return spring 21, and the operation member 16. The main shaft 41 is fixed to the seat fixing frame 31 in a cantilever manner by welding. The inner ring 1 is formed in a cylindrical shape having an inner flange 1a at one end, is fitted to the main shaft 41 by a central hole provided in the inner flange 1a, and is positioned in the radial direction. The inner ring 1 is a seat fixing frame 31.
, A fixture 36 such as a rivet that penetrates the inner collar 1a
Or it is fixed by welding or the like. On the outer diameter surface of the inner ring 1,
Cam surfaces 6 are provided at a plurality of locations in the circumferential direction. Apart from this, a circumferential surface portion 1b having a slightly smaller diameter is provided at an end edge on the inner flange 1a side, and a step surface and a sheet adjacent to the circumferential surface portion 1b are provided. An inner flange 2a of the outer race 2 is sandwiched in a circumferential groove formed between the fixed frame 1 and the outer ring 2 in a state where a gap is formed, thereby forming a radial and axial bearing portion 40 composed of a sliding bearing. The position of the outer race 2 in the radial and axial directions with respect to the inner race 1 and the seat fixing frame 31 is regulated by the support of the bearing portion 40, and there is a degree of freedom only in the rotational direction. The outer ring 2 has an outer collar 2b at an end opposite to the inner collar 2a, and the backrest fixing frame 32 is formed by using the outer collar 2b.
Fixed by welding. The operation member 16 is a plate-shaped member partially having a lever 16a (FIG. 2).
The main shaft 41 is axially positioned by a retaining ring 37 so as to be rotatably fitted to the main shaft 41 through a hole at the center and to face the retainer 4. Further, in order to limit the movement of the operation member 16 toward the retainer 4, the sleeve-shaped spacer 38 is provided.
Is provided on the outer periphery of the main shaft 41 between the inner flange 1a of the inner ring 1 and the operation member 16.

The structure of a portion that functions as the clutch 30 will be described. As shown in FIG. 4, the inner ring 1 is provided with cam surfaces 6 at a plurality of locations on the outer diameter surface in the circumferential direction. Each cam surface 6 is provided at equal intervals. These cam surfaces 6 are formed so that the central part in the circumferential direction is deep and becomes gradually shallow on both sides, and has a substantially V-shaped cross-sectional shape. The cam surface 6 may be a straight line as shown in FIG. 5A or a curved surface such as a concave arc as shown in FIG. The V-shaped opening angle α of the cam surface 6 is set to, for example, 155 ° to 175 °. The cam surface 6 is provided on the entire length of the inner ring 1 in the axial direction, but may be provided on a part of the axial direction. On one width surface of the inner ring 1 (the opposite side from the inner collar 1a), retainer fixing grooves 7 are provided at a plurality of circumferential positions. For example, the retainer fixing grooves 7 are provided alternately with the cam grooves 6. Cage fixing groove 7
Has a cross-sectional shape in which the center of the groove width is deep, and in this example, has a substantially V-shaped cross-sectional shape. The V-shaped slope is steeper than the cam groove 6. The inner ring 1 is cylindrical in this example, but may be a shaft. That is, the cam groove 6 and the retainer fixing groove 7 may be directly formed on the shaft such as the main shaft 41.

As shown in FIG. 3, the outer race 2 has a cylindrical inner circumferential surface 2a so that a rolling element 3 made of rollers can roll. The circumferential raceway surface 2a of the outer race 2, the cam groove 6 of the inner race 1, and the rolling element 3 form the inner race 1
Lock means 12 is provided for preventing relative rotation of the motor and the outer ring 2 in both forward and reverse directions.

As shown in FIG. 6, the retainer 4 is formed in a cylindrical shape, and pockets 8 for holding the rolling elements 3 are formed at a plurality of positions in the circumferential direction so as to penetrate the inner and outer diameters. Engaging projections 9 that engage with the retainer fixing grooves 7 and spring fixing pins 10 are respectively provided at a plurality of positions in the circumferential direction. The width of the pocket 8 in the circumferential direction of the cage is set to such a width that a small gap is formed between the pocket 8 and the rolling element 3 or a width that is a negative gap. The material of the retainer 4 is made of synthetic resin. The engagement projection 9 is provided on the inner surface of an inner flange 19 protruding from the inner diameter surface of the retainer 4 and has a triangular mountain shape. The spring fixing pin 10 is provided on a width surface of the retainer 4 opposite to the width surface where the engagement protrusion 9 is located. An engagement projection 9 of the retainer 4,
The retainer fixing groove 7 of the inner ring 1 constitutes the guide means 14. The lock release means 13 is composed of the guide means 14 and the retainer 4.

FIG. 6B shows a state in which the elastic body 5 is attached to the retainer 4. The elastic body 5 includes a ring-shaped side plate 5a,
A plurality of arm-shaped spring pieces 5 extending radially from the side plate
b). The spring piece 5b extends obliquely to the outer diameter side from the side plate 5a and is bent so that the tip portion is substantially parallel to the axial direction, and the tip portion contacts the inner diameter surface of the outer ring 2 in a pressed state. The elastic body 5 is fixed to the retainer 4 by inserting a spring fixing pin 10 provided on the retainer 4 into a hole of the side plate 5a and caulking. The fixing of the elastic body 5 may be performed by welding, screwing, tacking, or bonding, instead of by caulking.

The elastic member 5 only needs to have a function of holding the retainer 4 with a constant frictional force with the rotation of the outer ring 2 so that the elastic member 5 can be made of an elastic member such as rubber in addition to the spring member. May be used. For example, a ring-shaped elastic body (not shown) made of an O-ring or the like may be embedded in a circumferential groove provided on the outer diameter surface of the retainer 4. Also, instead of providing such an elastic body, the retainer 4 may be formed in a polygonal shape, or a protrusion may be provided on the outer diameter surface of the retainer 4 so that a plurality of locations in the circumferential direction of the retainer 4 May be obtained such that a constant frictional force is generated to the extent that the retainer 4 itself rotates with the outer race 2 due to the elasticity of the retainer 4 itself.

The operating member 16 is used to apply a radial force to the retainer 4 at a plurality of circumferential positions (four in the drawing) on a surface facing the width surface of the retainer 4 as the operating member 16 rotates. A cam surface 17 is provided. Further, a plurality of operation cam surfaces 18 respectively contacting these operation cam surfaces 17 are formed on the width surface of the retainer 4. These operation cam surfaces 17, 1
8 is a V-shaped mountain with a gentle slope. A portion between the adjacent operation cam surfaces 17 is a flat surface portion 17a. The operation cam surfaces 17 and 18 have a gentle gradient V.
The letter-shaped chevron does not need to be on both sides, and only one may be a partial convex part. As shown in FIG. 3 (B), the return spring 21 provides an elastic restoring force for returning the retainer 4 to the operation member 16 side, and the retainer 4 and the inner flange 2 of the outer ring 2 are provided.
a. As the return spring 21, a spring member such as a disc spring or a leaf spring is used. 2 is provided between the operation member 16 shown in FIG.
As shown in FIG. 7, a lever return spring 22 for urging the lever 16a downward is provided.

The operation of the above configuration will be described. Lever 16a
Is in the neutral position, the lever 16a in this example is
Is lowered almost horizontally, the operation cam surface 18 of the width surface of the retainer 4 and the operation cam surface 17 of the operation member 16a are opposed to each other by the convex portion and the concave portion. Is in a natural state without any external force in the axial direction. In this state, the clutch has a rotation lock function and the backrest 3
4 cannot move forwards or backwards, either up or down. That is, the retainer 4 is loosely engaged with the retainer fixing groove 7 provided in the inner ring 1 by the engagement projection 9, and the retainer 4 is freely rotated with respect to the inner ring 1 within the gap. The phase changes. Therefore, when the outer ring 2 rotates slightly in either the forward or reverse direction, the retainer 4 rotates with the outer ring 2, and the rolling element 3 is biased from the center of the cam groove 3 by the movement of the retainer 4. Shallow position,
The rotation between the inner and outer rings 1 and 2 is locked.

Next, when the lever 16a is raised by a predetermined angle (for example, approximately 45 °), the operating cam surface 1
7 and the operation cam surface 18 of the retainer 4 face each other with the convex portion, and the retainer 4 is pushed in the axial direction by the operation member 16. As a result, the engaging projection 9 of the retainer 4 closely fits into the retainer fixing groove 7 of the inner race 1, and the guiding action accompanying this fitting causes the retainer 4 to move.
And the rotational phase of the inner ring 1 are matched. Therefore, the rolling element 3 held in the pocket 8 of the retainer 4 is located at the center of the cam surface 6 and the position is held, so that the frictional contact of the rolling element 3 is eliminated and the rotation lock function is achieved. Lost. Thus, the backrest 34 is free to move in either direction. In this case, when the backrest 34 is depressed, the force of the human back is used, and when the backrest 34 is raised, the restoring force of the spring member 35 is used. After the position of the backrest 34 is determined, when the lever 16a is returned to the original lower position, the rotation lock function is restored, and the backrest 34 is fixed.

According to the seat back tilt adjusting device, the backrest 34 can be fixed at an arbitrary angle. Further, unlike the conventional ratchet type, there is no generation of abnormal noise due to incomplete meshing or the like. As described above, the seat back tilt adjusting device can provide an operational feeling and a high-class feeling which are not available in conventional products.

7 to 9 show another embodiment of the present invention. In this example, a rotation lock state and an unlock state are switched by applying a radial external force to the retainer 4. In this example, the cage 4 and the inner ring 1
Except that the configuration of the guide means 14A constituted by a part of the above and the relationship between the operation member 16A and the retainer 4 are changed,
It has the same structure as the examples of FIGS. However, the retainer 4 is made of an elastically deformable material. In this example, inner ring 1
A retainer fixing groove 7A that engages with the engaging projection 9A of the retainer 4 is provided on an outer diameter surface at a side edge of the retainer. The retainer 4 has an engagement projection 9A on the inner diameter surface. The retainer fixing groove 7A has a V-groove shape, and the engagement projection 9A has a triangular mountain shape corresponding to the V-groove-shaped retainer fixing groove 7A. The retainer fixing groove 7A and the engagement protrusion 9A constitute guide means 14A. The shape of the cam groove 6 of the inner ring 1 is the same as the example of FIG. Further, the operation member 16A has a flange-shaped ring portion 16b located on the outer periphery of the retainer 4, and the operation member 16A is provided at a plurality of circumferential positions (four in the drawing) on the inner diameter surface of the ring portion 16b. An operation cam surface 17A for applying a radial force to the retainer 4 with the rotation is provided. Operation cam surface 17
A is formed as a straight line which is a chord of a part of a circle which is an inner diameter surface of the ring portion 16b. In addition, these operation cam surfaces 17 are provided.
A, a plurality of operating cam surfaces 18A each contacting the
Is formed by a projection having an arc-shaped cross section on the outer diameter surface of the.

In this configuration, when the operation member 16A is rotated, the retainer 4 is elastically deformed by the engagement of the operation engagement surfaces 17A and 18A, and the retainer 4 is inserted into the retainer fixing groove 7A of the inner race 1. The engagement protrusions 9A mesh (FIG. 8B), and the position of the retainer 4 is regulated. Thus, the rotation lock is released. When the operation member 16A is returned to the original angle, the rotation lock state is established. FIG. 9B shows a rotation locked state when the outer ring 2 is about to rotate clockwise and a rotation locked state when it is about to rotate counterclockwise, respectively.

FIGS. 10 and 11 show still another embodiment of the present invention. In this example, a sprag 3A is provided instead of the rolling element 3 and the cam groove 6 in the example of FIG. The sprag 3A has a substantially T-shaped side surface shape, and its base end is swingably fitted to a fulcrum groove 6A having an arc-shaped cross section provided on the outer diameter surface of the inner ring 1. FIG.
As shown in FIGS. 1 (B) and 1 (C), the sprag 3A locks the relative rotation between the inner and outer wheels 1 and 2 by inclining in any direction, forward and reverse. The retainer 4 has a pocket 8A into which the leg piece of the sprag 3A is fitted, and has a guide means 14 comprising a retainer fixing groove 7 and an engagement protrusion 9 having the same configuration as the example of FIG.
Thus, the inner ring 1 can be restrained in the same phase. Other configurations are the same as those in the examples of FIGS. Also in this configuration, the rotation of the inner ring 1 and the outer ring 2 is locked by the sprags 3A so that they cannot be rotated relative to each other at all times.
By operating 6, the inner ring 1 and the outer ring 2 can be rotated in both forward and reverse directions. Therefore, in the unlocked state, the backrest 34 can be freely adjusted in both the falling direction and the raising direction.

[0024]

According to the seat backrest inclination adjusting device of the present invention, the structure of the clutch provided between the seat fixing frame and the backrest fixing frame is different from that of the inner ring and the outer ring, which are rotatable in the forward and reverse directions, and which is always between the inner and outer rings. Locking means for locking the rotation in both forward and reverse directions by frictional contact, unlocking means for unlocking the locking means in a state in which the locking means can be rotated in both forward and reverse directions by applying a predetermined external force, and an operation for applying the external force Since the member is provided, the inclination can be adjusted to a desired angle in a stepless manner, the tilting direction and the raising direction can be simultaneously adjusted freely, and the operability is good, the structure is simple and the cost can be reduced. In particular, when a cam surface and a rolling element are used for the lock means, or when a sprag is used, smooth operation is possible, and smooth operability and a sense of quality can be obtained.

[Brief description of the drawings]

FIG. 1 is a side view of a seat provided with a seat back tilt adjusting device according to an embodiment of the present invention.

FIG. 2 is a side view of the seat back tilt adjusting device.

3 is a partially cutaway front view of the seat back tilt adjusting device, and FIG. 3B is a sectional view taken along the line III-111 of FIG. 3A.

FIG. 4 is a perspective view of an inner race of the clutch.

FIG. 5 is an enlarged sectional view showing various examples of a cam surface of the inner ring.

FIG. 6A is a perspective view of a retainer and an operation member of the clutch, and FIG. 6B is a perspective view of a state where an elastic body is attached to the retainer.

FIG. 7 is a partially broken front view of a seat back tilt adjusting device according to another embodiment of the present invention.

FIG. 8 is an explanatory diagram of the operation.

FIG. 9 is an operation explanatory view in another operation state.

FIG. 10 is a partially broken front view of a seat back tilt adjusting device according to still another embodiment of the present invention.

FIG. 11 is an explanatory diagram of the operation.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Inner ring 2 ... Outer ring 3 ... Rolling element 3A ... Sprag 4 ... Cage 5 ... Elastic body 6 ... Cam surface 7 ... Cage fixing groove 9 ... Engagement protrusion 12 ... Locking means 13 ... Lock release means 14 ... Guide means Reference Signs List 16 operating member 16a lever 16A operating member 17, 18 operating cam surface 17A, 18A operating cam surface 21 return spring 30 clutch 31 seat fixing frame 32 backrest fixing frame 33 seat 34 backrest 41 ... spindle

Claims (5)

[Claims] An inner ring and an outer ring constituting a clutch are fixed to one of a seat fixing frame and the other is fixed to a backrest fixing frame. Lock means for locking the forward and reverse rotation between these inner and outer rings by frictional contact, and lock release means for releasing the lock of the lock means to be rotatable in both forward and reverse directions by applying a predetermined external force, A seat backrest inclination adjusting device comprising: an operating member that applies the external force. 2. The lock means is provided on one of an outer diameter surface of the inner ring and an inner diameter surface of the outer ring, and on the other of the outer diameter surface of the inner ring and the inner diameter surface of the outer ring. A plurality of cam surfaces facing the circumferential raceway surface, and a plurality of rolling elements interposed between the circumferential raceway surface and each cam surface. The rolling members are formed so as to be shallow on both sides, and the rolling members are biased in any direction from the center position to frictionally contact with the rolling members to lock the relative rotation of the inner and outer rings, and the lock release means includes: By applying a predetermined external force to the cage formed with a pocket for holding each rolling element in the position-regulated state,
2. The seat backrest inclination adjusting device according to claim 1, further comprising a guide unit for fixing the retainer to a side wheel on which the cam surface is formed so that the rolling element is located at a center position of the cam surface. 3. The retainer fixing groove provided on one of the cam ring forming side wheel and the retainer of the inner ring and the outer ring, and the engaging projection provided on the other of the inner ring and the outer ring. And these retainer fixing grooves and engagement projections are
In the state where the external force is not applied, the two mesh with each other in a loose state, and in the state where the external force is applied, they are intimately engaged with each other, and the frictional force is applied between the inner race and the outer race around the circumferential raceway surface forming side wheel and the retainer. 3. The seat back tilt adjusting device according to claim 2, further comprising an elastic body. 4. An inner ring is fixed to the seat fixing frame, an outer ring is fixed to the backrest fixing frame, and the operating member is rotatable on a main shaft provided on the seat fixing frame at a position concentric with the inner ring. The mounting and retainer fixing groove and the engaging projection are engaged with each other in the axial direction, and the operation member and the retainer are subjected to the axial force as the external force as the operation member rotates, acting on the retainer. 4. The seat backrest tilt adjusting device according to claim 3, wherein each of the operation cam surfaces is provided. 5. A sprag provided on one of an outer diameter surface of the inner ring and an inner diameter surface of the outer ring so as to be swingable in a circumferential direction of the inner and outer rings, and an outer diameter surface of the inner ring. And a sprag contact surface in the form of a cylinder provided on the other of the inner diameter surfaces of the outer ring, wherein the sprag is in a non-contact state with the sprag contact surface at a neutral angle to allow relative rotation of the inner and outer rings, and By tilting in the opposite arbitrary direction, the sprag contact surface is brought into frictional contact to lock the relative rotation between the inner and outer wheels, and the unlocking means includes a state in which the sprag is held at a neutral angle and a state in which the sprag is swingable. 2. The seat backrest inclination adjusting device according to claim 1, wherein the device is switched to: