JP7633515B2 - Reclining device - Google Patents

Description

The present invention relates to a reclining device that adjusts the tilt angle between a first member and a second member that tilt relative to one another.

Conventionally, the reclining device disclosed in Patent Document 1 below is known as a reclining device that adjusts the tilt angle between a first member and a second member that tilt relative to one another. This reclining device is configured to switch between a locked state in which each lock gear engages with a gear plate and an unlocked state in which the engagement is released, depending on the state of contact between the cam that rotates in response to the operation of the reclining operation lever and the four lock gears.

In addition, a slidable movable guide is interposed between each of the lock gears and the fixed guides, and the width of each of these movable guides gradually narrows from the outer end to the inner end. The sliding surface of the movable guide on the lock gear side is parallel to the direction of movement of the lock gear, and the sliding surface on the fixed guide side is inclined relative to the sliding surface on the lock gear side. A spring is engaged with each of the movable guides, and the spring biases the movable guide inward toward the base plate. As a result, the movable guide is always wedged between the lock gear and the fixed guide, and the fixed guide, lock gear, and movable guide fit together, eliminating any gaps between the various components. This reliably eliminates any backlash in the front-to-rear direction of the seat back, enabling reliable locking and unlocking.

JP 2012-056397 A

In recent years, there has been a demand for thinner reclining devices (shorter axial length), and efforts are being made to shorten the axial length of each component that makes up the reclining device. To achieve this, it is necessary to make the axial length of the cam and lock gear shorter than that of conventional products.

However, when the axial lengths of the cam and lock gear are shortened, the contact area (contact width in the axial direction) between the cam surface on the outer periphery of the cam and the inner end face (end face on the inner periphery) of the lock gear becomes smaller. The cam and lock gear are housed in a housing space formed by a gear plate and a base plate together with the cam lever, spring, etc., and each part in this housing space is allowed a certain degree of movement (deviation) by design. Therefore, when the cam shifts in the axial direction relative to the lock gear, the contact area becomes even smaller. When the contact area becomes smaller in this way and the cam presses the lock gear outward in a locked state, the stress acting on the contact area becomes large, which may cause pressure loss at the contact site.

The present invention was made to solve the above-mentioned problems, and its purpose is to provide a configuration that can ensure the necessary contact area between the cam surface of the cam and the inner end surface of the lock gear even if the cam is displaced axially relative to the lock gear.

In order to achieve the above object, the invention of claim 1 described in the claims is as follows:
A reclining device (20) for adjusting a tilt angle between a first member (11, 11a) and a second member (12, 12a) that tilt relatively, comprising:
A base plate (30) attached to the first member;
a gear plate (40) attached to the second member and assembled to be rotatable relative to the base plate and having internal teeth (41);
a lock gear (61, 62) assembled to be guided radially slidably by utilizing guide surfaces (33a, 33b, 34a, 34b) formed on the base plate, the lock gear having external teeth (61a, 62a) meshable with the internal teeth;
a cam (70) that, when rotated around a predetermined rotation axis, abuts against an inner end surface (61c, 62c) of the lock gear from the radially inner side at a cam surface (72), thereby causing the outer teeth to mesh with the inner teeth;
A biasing member (80) that biases the cam in a direction in which the external teeth mesh with the internal teeth;
a release member (90) capable of releasing the meshing between the external teeth and the internal teeth by rotating the cam against the biasing force of the biasing member;
Equipped with
a recess into which one axial side of the cam fits, is formed on a surface of the base plate facing the lock gear and the cam;
The cam is characterized in that the cam surface has an axial length longer than the axial length of the inner end face of the lock gear.
The symbols in parentheses above indicate the corresponding relationship with the specific means described in the embodiments described later.

In the invention of claim 1, a recess is formed on the surface of the base plate facing the lock gear and cam into which one axial side of the cam fits, and the cam is formed so that the axial length of the cam surface is longer than the axial length of the inner end surface of the lock gear. As a result, even if the cam shifts axially to the other side relative to the lock gear, the part of the cam surface that fit into the recess abuts against the inner end surface of the lock gear, so that the necessary contact area can be secured between the cam surface of the cam and the inner end surface of the lock gear.

In the invention of claim 2, the cam is formed so that the axial length of the cam surface is equal to the sum of the axial length of the inner end surface and the depth of the recess. As a result, even if one axial side of the cam enters the recess so as to contact the bottom surface, the other axial side of the cam surface and the other axial side of the inner end surface are flush with each other, so that the necessary contact area can be secured between the cam surface of the cam and the inner end surface of the lock gear.

1 is a side view showing an outline of the configuration of a vehicle seat on which a reclining device of the present invention is installed. FIG. FIG. 3 is a cross-sectional view taken along a line X1-X1 shown in FIG. 2. 3 is a cross-sectional view taken along line X2-X2 of FIG. 2. 10 is an explanatory diagram illustrating the relationship between the axial length of a cam surface of a cam, the axial length of an inner end face of a lock gear, and the depth of a recess in a base plate, using an enlarged cross section. FIG. Figure 7(A) is an explanatory diagram illustrating a state in which the cam is in contact with the bottom surface of the recess in the base plate on one axial side, and Figure 7(B) is an explanatory diagram illustrating a state in which the cam etc. is shifted to the other axial side relative to Figure 7(A).

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a reclining device according to the present invention will be described with reference to the drawings.
As shown in FIG. 1, a vehicle seat 10 equipped with a reclining device 20 of the present invention has a seat cushion 11 and a seat back 12 as its main components, with a seat bracket (lower bracket) 11a fixed to the seat cushion 11 and a seat back bracket (upper bracket) 12a fixed to the seat back 12.

The lower bracket 11a and the upper bracket 12a are fixed to the respective rotating parts of the round reclining unit 21, and are connected to each other so as to be capable of rotating relative to each other. This allows the tilt angle of the seat back 12 relative to the seat cushion 11 to be adjusted. The seat cushion 11 and the lower bracket 11a can be an example of a "first member", and the seat back 12 and the upper bracket 12a can be an example of a "second member".

A reclining operation lever 23 is attached to the center shaft 22 in the center of the round reclining unit 21. The round reclining unit 21, the center shaft 22, and the reclining operation lever 23 constitute the reclining device 20. When the reclining operation lever 23 is pulled upward, the reclining device 20 is unlocked and the tilt angle of the seat back 12 can be adjusted. Here, the range of angle A shown in FIG. 1 where the seat back 12 is tilted backward is the tilt adjustment range where the seat back 12 is locked at the angle position when the reclining operation lever 23 is released, and the range of angle B shown in FIG. 1 where the seat back 12 is tilted forward is the free rotation range corresponding to the lock-free state where the unlocked state continues even if the reclining operation lever 23 is released. As can be seen from FIG. 1, the seat back 12 can be rotated from a forward tilt position where it contacts the seat cushion 11 to a backward tilt position where it is flat against the seat cushion 11. The structure of such a reclining device 20 will be described below.

As shown in Figures 2 and 3, the round reclining unit 21 is configured by overlapping a substantially disc-shaped base plate 30 with a substantially bowl-shaped gear plate 40 and assembling a cover bracket 50, so that the base plate 30 and the gear plate 40 are held so as to be rotatable relative to each other and their relative movement in the axial direction is suppressed. For convenience, the center shaft 22 and reclining operation lever 23 are not shown in Figures 2 and 3, and in Figures 4 and 5, only the area near the internal teeth 41 of the gear plate 40 is shown, with the cover bracket 50 not shown.

A cavity (space) C is formed between the base plate 30 and the gear plate 40. As shown in Figures 2 to 5, this cavity C contains a total of four lock gears, a pair of first lock gears 61 and a pair of second lock gears 62, a central cam 70, two roughly arc-shaped spring members 80, and a roughly disk-shaped cam lever 90, as well as other components for locking and unlocking. In the following description, the left side of Figure 2 is one axial side, and the right side is the other axial side.

The base plate 30 has a plurality of protrusions 30b formed on one axial side (hereinafter also referred to as the mounting surface 30a), and is attached to the lower bracket 11a by engaging each of these protrusions 30b with an engagement hole (not shown) in the lower bracket 11a. As shown in FIG. 4, the base plate 30 has four guide protrusions 31, 32, 31, 32 formed on the other axial side for guiding each lock gear 61, 62 in the radial direction. In the following description, as shown in FIG. 4, of the pair of guide surfaces for guiding the first lock gear 61, the guide surface of the guide protrusion 31 is referred to as the first guide surface 33a on one side, and the guide surface of the guide protrusion 32 is referred to as the first guide surface 33b on the other side. Also, of the pair of guide surfaces for guiding the second lock gear 62, the guide surface of the guide protrusion 32 is referred to as the second guide surface 34a on one side, and the guide surface of the guide protrusion 31 is referred to as the second guide surface 34b on the other side.

The base plate 30 is formed with an insertion hole 35 through which the shaft portion (not shown) of the center shaft 22 is inserted. In addition, a circular recess 36 is provided on the other axial side of the base plate 30 at a position inside the guide protrusions 31, 32 so as to be coaxial with the insertion hole 35. As shown in FIG. 2, the recess 36 is formed so that one axial side of the cam 70 fits into it to be able to rotate relative to the cam 70. The depth H of this recess 36 can be set to be equal to the allowable axial deviation between the cam 70 and the lock gears 61, 62.

The gear plate 40 has internal teeth 41 formed around the entire inner circumferential surface. The gear plate 40 has multiple protrusions 40a formed on its back surface (the surface on the other axial side), and is attached to the upper bracket 12a by engaging each of these protrusions 40a with an engagement hole (not shown) in the upper bracket 12a.

In addition, two arc-shaped steps are arranged at 180° intervals on the inner peripheral surface of the gear plate 40, which are coaxial with the internal teeth 41. These arc-shaped steps are intended to achieve the above-mentioned lock-free state, and are formed so that the angular range in which the protrusion 63 (described later) of the first lock gear 61 abuts from the inner peripheral side corresponds to the above-mentioned free rotation range.

As shown in Figs. 3 and 4, external teeth 61a, 62a that can mesh with the internal teeth 41 of the gear plate 40 are formed on the outer periphery of both first lock gears 61 and both second lock gears 62. Each lock gear 61, 62 is assembled so as to be guided radially slidably using the guide surfaces 33a, 33b, 34a, 34b of the base plate 30. Specifically, both first lock gears 61 are guided by one first guide surface 33a of the guide protrusion 31 and a movable guide 37 (described later) guided by the other first guide surface 33b of the guide protrusion 32, and are supported so as to be slidable only in the radial direction. In addition, both second lock gears 62 are guided by one second guide surface 34a of the guide protrusion 32 and the other second guide surface 34b of the guide protrusion 31, and are supported so as to be slidable only in the radial direction.

In addition, each of the first lock gears 61 has a protrusion 61b that protrudes toward the other axial side (gear plate side), and each of the second lock gears 62 has a protrusion 62b that protrudes toward the other axial side. Both protrusions 61b and 62b function to control the radial movement of each of the lock gears 61, 62 by being guided by a rotating cam lever 90 as described below. In addition, each of the first lock gears 61 has a protrusion 63 on the outside of the protrusion 61b, and both protrusions 63 are formed so that the meshing between the internal teeth 41 and the external teeth 61a is maintained by abutting against the arc-shaped step portion of the gear plate 40 from the inner circumferential side.

The movable guide 37 is formed in a wedge shape so that its width gradually narrows from one end to the other end, and is arranged so as to be slidable between the first lock gear 61 and the other first guide surface 33b of the guide protrusion 32. An engagement hole 37a for engaging one end of a spring member 80 is formed in each of the movable guides 37, and by engaging one end of the spring member 80 with this engagement hole 37a, the both movable guides 37 are biased inwardly of the base plate 30 by the spring member 80. As a result, the movable guide 37 is always in a state of being wedged between the first lock gear 61 and the other first guide surface 33b, and the first lock gear 61, the other first guide surface 33b, and the movable guide 37 are tightly fitted together (fitted together), eliminating any gaps between the respective members. Therefore, rattling in the front-rear direction of the seat back 12 is eliminated. The spring member 80 can be an example of a "biasing member".

A plate-shaped cam 70 is rotatably arranged on the base plate 30, with a through hole 71 formed therein for inserting the shaft portion of the center shaft 22, utilizing the recess 36. The cam 70 is formed so that the cam surfaces 72 abut against the inner end faces 61c of both lock gears 61 and the inner end faces 62c of both lock gears 62 from the radially inner side, respectively, and mesh the external teeth 61a, 62a of the lock gears 61, 62 with the internal teeth 41 of the gear plate 40 when rotated to a predetermined state around the shaft portion serving as the rotation axis. The cam 70 also has two engagement holes 73 on its side with which the other end of the spring member 80 engages, and two cylindrical protrusions 74 protruding to the other axial side.

In particular, the cam 70 is formed so that the axial length T1 of the cam surface 72 is longer than the axial length T2 of the inner end faces 61c, 62c of the lock gears 61, 62. More specifically, the cam 70 is formed so that the axial length T1 of the cam surface 72 is equal to the sum of the axial length T2 of the inner end faces 61c, 62c and the depth H of the recess 36 of the base plate 30. Therefore, as shown in FIG. 6, when one axial side of the cam 70 enters so as to contact the bottom surface 36a of the recess 36, the other axial side of the cam surface 72 and the other axial side of the inner end faces 61c, 62c are flush with each other.

As shown in FIG. 5, the cam 70 is strongly biased in the lock rotation direction (clockwise in FIG. 4 and FIG. 5) by engaging with the other ends of the two spring members 80. As a result, the cam 70 abuts the inner end faces 61c, 62c of each lock gear 61, 62 with the cam surface 72, and the biasing force in the lock rotation direction by both spring members 80 strongly biases each lock gear 61, 62 radially outward.

The shaft portion of the center shaft 22 is inserted into the through hole 71 of the cam 70, and by rotating the center shaft 22, the cam 70 can be rotated in the unlock rotation direction (counterclockwise in Figures 4 and 5) against the biasing force of both spring members 80.

As shown in FIG. 5, the cam lever 90 has a through hole 91 that fits over both protrusions 74 of the cam 70, two cam holes 92, and two cam holes 93. The cam lever 90 is assembled to the cam 70 and the lock gears 61 and 62 with the through holes 91 and the protrusions 74 fitting together, the protrusions 61b inserted into the cam holes 92, and the protrusions 62b inserted into the cam holes 93.

As a result, when the cam lever 90 rotates together with the cam 70 in the unlock rotation direction, the inner peripheral edge of the cam hole 92 abuts against the projections 61b of the first lock gear 61, and the inner peripheral edge of the cam hole 93 abuts against the projections 62b of both second lock gears 62. When the cam lever 90 rotates further in the unlock rotation direction, these projections 61b and 62b are biased radially inward by the inner peripheral edges of the cam holes 92 and 93, causing the lock gears 61 and 62 to move radially inward in unison. The cam lever 90 can be considered an example of a "release member."

The reclining device 20 thus constructed has the lock gears 61, 62, the movable guide 37, the cam 70, etc. arranged in the cavity C and assembled together into a base plate 30 and a gear plate 40, which are integrated by ring crimping the side periphery of the cover bracket 50. This allows the base plate 30 and the gear plate 40 to be held so that they can rotate relative to each other, while preventing relative movement in the axial direction.

Then, the reclining operation lever 23 is attached to the center shaft 22, the shaft portion of which is inserted into the through hole 71 of the cam 70, to complete the reclining device 20 shown in FIG. 2. With the reclining device 20 thus configured, the seat cushion 11 and the seat back 12 are connected by the reclining device 20 so that they can tilt relative to each other by engaging each of the projections 30b of the base plate 30 with the engagement holes of the lower bracket 11a and each of the projections 40a of the gear plate 40 with the engagement holes of the upper bracket 12a.

Next, the unlocked and locked states of the reclining device 20 according to this embodiment configured as described above will be described below.

(Unlocked)
First, the unlocked state of the reclining device 20 will be described.
When an occupant unlocks the seat back 12 to adjust the inclination angle of the seat back 12, the occupant operates the reclining operation lever 23 to rotate the center shaft 22 in the unlock rotation direction. Then, the cam 70 rotates together with the center shaft 22 in the unlock rotation direction against the biasing forces of the two spring members 80.

When the cam 70 rotates in the unlock rotation direction, the cam surface 72 of the cam 70 is released from contact with the inner end faces 61c, 62c of each of the lock gears 61, 62, and the biasing force of the cam 70 biasing each of the lock gears 61, 62 radially outward is released. This allows each of the lock gears 61, 62 to move radially inward, and the meshing between the internal teeth 41 of the gear plate 40 and the external teeth 61a, 62a of each of the lock gears 61, 62 becomes disengageable.

Then, as the cam lever 90 rotates together with the cam 70 in the unlock rotation direction, the inner peripheral edges of the cam holes 92, 93 of the cam lever 90 come into contact with the protrusions 61b, 62b of the lock gears 61, 62, actively moving the lock gears 61, 62 radially inward, and disengaging the internal teeth 41 from the external teeth 61a, 62a.

As described above, when the meshing between the internal teeth 41 and the external teeth 61a, 62a is released, the gear plate 40 becomes free to rotate, and the round reclining unit 21 becomes unlocked. When the round reclining unit 21 becomes unlocked, the reclining device 20 becomes unlocked, and when the seat back 12 is tilted backward, the inclination angle of the seat back 12 becomes freely adjustable (see angle A in Figure 1).

(Unlocked state)
Next, the unlocked state of the reclining device 20 will be described.
In the above-described unlocked state, when the seat back 12 is tilted forward, the base plate 30 and the gear plate 40 rotate relative to each other, and both first lock gears 61 move to positions where the protrusions 63 can abut against the arc-shaped stepped portions of the gear plate 40. In this state, when the reclining operation lever 23 is loosened, the cam 70 rotates in the lock rotation direction due to the biasing forces of both spring members 80, and the rotation of the cam 70 biases each of the lock gears 61, 62 radially outward.

At this time, the protrusions 63 of both first lock gears 61 abut against the arc-shaped stepped portions of the gear plate 40, so that the internal teeth 41 and the external teeth 61a, 62a are kept disengaged. Therefore, while the protrusions 63 abut against the arc-shaped stepped portions of the gear plate 40, the unlocked state is maintained even if the seat back 12 is tilted forward so that the base plate 30 and the gear plate 40 rotate relative to each other (see angle B in Figure 1).

(Locked state)
Next, the locked state of the reclining device 20 will be described.
When the occupant has finished adjusting the reclining angle of the seat back 12 , the reclining operation lever 23 is released, and the cam 70 is rotated in the lock rotation direction by the biasing forces of both spring members 80 .

When the cam surface 72 of the rotating cam 70 comes into contact with the inner end surfaces 61c, 62c of the lock gears 61, 62, the lock gears 61, 62 are biased radially outward. This causes the external teeth 61a, 62a of the lock gears 61, 62 to move radially outward so as to mesh with the internal teeth 41 of the gear plate 40. Then, when the external teeth 61a, 62a of the lock gears 61, 62 mesh with the internal teeth 41 of the gear plate 40, the rotation of the gear plate 40 is restricted, and the reclining device 20 enters a locked state.

Next, the effect of providing the recess 36 in the base plate 30 will be described with reference to Figures 7(A) and (B). Note that in Figures 7(A) and (B), the dashed-dotted rectangular area on the left side is an enlarged view of the dashed-dotted rectangular area on the right side.

The reclining device 20 is assembled into the vehicle seat 10 so that the axial direction is approximately horizontal, so that when the reclining device 20 repeatedly transitions between the locked state, unlocked state, and unlocked state as described above, each part in the cavity C moves within the range of allowable axial displacement. At that time, as can be seen from Figures 7(A) and (B), the cam 70 may also shift in the axial direction relative to the lock gears 61 and 62.

In the reclining device 20 according to this embodiment, a circular recess 36 into which one axial side of the cam 70 fits is formed on the surface of the base plate 30 facing the lock gears 61, 62 and the cam 70, and the cam 70 is formed so that the axial length T1 of the cam surface 72 is longer than the axial length T2 of the inner end faces 61c, 62c of the lock gears 61, 62.

Therefore, in the locked state, when one axial side of the cam 70 is inserted so as to contact the bottom surface 36a of the recess 36 as shown in FIG. 7(A), the other axial side of the cam surface 72 abuts against the inner end surfaces 61c, 62c of the lock gears 61, 62. Even if the cam 70 is shifted to the other axial side relative to the lock gears 61, 62 as shown in FIG. 7(B), the one axial side of the cam surface 72 abuts against the inner end surfaces 61c, 62c of the lock gears 61, 62. In other words, the contact area between the cam surface 72 and the inner end surfaces 61c, 62c does not change due to the axial shift between the cam 70 and the lock gears 61, 62. Therefore, even if the cam 70 is shifted in the axial direction relative to the lock gears 61, 62, the necessary contact area can be secured between the cam surface 72 of the cam 70 and the inner end surfaces 61c, 62c of the lock gears 61, 62.

In particular, the cam 70 is formed so that the axial length T1 of the cam surface 72 is equal to the sum of the axial length T2 of the inner end faces 61c, 62c and the depth H of the recess 36 (see FIG. 6). As a result, even if one axial side of the cam 70 enters so as to contact the bottom surface 36a of the recess 36, the other axial side of the cam surface 72 and the other axial side of the inner end faces 61c, 62c are flush with each other, so that the necessary contact area can be secured between the cam surface 72 of the cam 70 and the inner end faces 61c, 62c of the lock gears 61, 62.

[Other embodiments]
The present invention is not limited to the above-described embodiment, and may be embodied as follows, for example.
(1) The recess 36 of the base plate 30 does not have to be formed in a circular shape, and may be formed in a shape that allows one axial side of the cam 70 to fit therein and rotate relatively.

(2) The recess 36 is not limited to being formed so that the sum of its depth H and the axial length T2 of the inner end faces 61c, 62c is equal to the axial length T1 of the cam surface 72. For example, depending on the environment in which the reclining device 20 is used, the recess 36 may be formed so that the sum of its depth H and the axial length T2 of the inner end faces 61c, 62c is smaller than the axial length T1 of the cam surface 72.

(3) The present invention is not limited to being applied to a reclining device 20 in which the base plate 30 is attached to the lower bracket 11a and the gear plate 40 is attached to the upper bracket 12a, but may also be applied to a reclining device in which the base plate is attached to the upper bracket 12a and the gear plate is attached to the lower bracket 11a. In this configuration, the upper bracket 12a and the seat back 12 may correspond to the "first member," and the lower bracket 11a and the seat cushion 11 may correspond to the "second member."

10... Vehicle seat 11... Seat cushion (first member)
11a...Lower bracket (first member)
12...Seat back (second member)
12a...Upper bracket (second member)
20... Reclining device 30... Base plate 33a, 33b... First guide surface (guide surface)
34a, 34b...second guide surface (guide surface)
36: Recess 36a: Bottom surface 40: Gear plate 41: Internal teeth 61: First lock gear 61a: External teeth 61c: Inner end surface 62: Second lock gear 62a: External teeth 62c: Inner end surface 70: Cam 72: Cam surface 80: Spring member (biasing member)
90...Cam lever (release member)

Claims (2)

A reclining device that adjusts a tilt angle between a first member and a second member that tilt relatively, comprising:
A base plate attached to the first member;
a gear plate attached to the second member and assembled to be rotatable relative to the base plate, the gear plate having internal teeth;
a lock gear that is assembled so as to be guided radially slidably by utilizing a guide surface formed on the base plate, and has external teeth that can mesh with the internal teeth;
a cam that, when rotated about a predetermined rotation axis, abuts against an inner end surface of the lock gear from the inside in the radial direction at a cam surface, thereby causing the external teeth to mesh with the internal teeth;
a biasing member that biases the cam in a direction in which the external teeth mesh with the internal teeth;
a release member capable of releasing the meshing between the external teeth and the internal teeth by rotating the cam against the biasing force of the biasing member;
Equipped with
a recess into which one axial side of the cam fits, is formed on a surface of the base plate facing the lock gear and the cam;
The cam is formed so that the axial length of the cam surface is longer than the axial length of the inner end face of the lock gear. The reclining device according to claim 1, characterized in that the cam is formed so that the axial length of the cam surface is equal to the sum of the axial length of the inner end surface and the depth of the recess.

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