JP2021146833A - Reclining device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a configuration in which a pair of cams can be rotated according to the rotation of a rotating shaft by using a connecting member having a constant radial thickness.
SOLUTION: A metal connecting member 80 having a constant radial thickness and sliding with respect to an outer peripheral surface of an inner cylinder portion 24e of an internal gear 24 as the shaft 25 rotates, and a tip side It is formed in a wedge shape so that the thickness in the radial direction becomes thin, and is inserted between the connecting member 80 and the resin bush 23b constituting the inner peripheral surface of the external gear 23 so that the tip sides are separated from each other. A pair of metal cams 31a and 31b and a spring 29 for urging the pair of cams 31a and 31b in a direction to separate them from each other are provided.
[Selection diagram] FIG. 10

Description

The present invention relates to a seat reclining device that holds the seat back tiltably with respect to the seat cushion.

Conventionally, a reclining device disclosed in Patent Document 1 below is known as a seat reclining device that holds a seat back tiltably with respect to a seat cushion. This reclining device has a U-shaped connecting member and a pair of wedge-shaped members that rotate together with a rotating shaft between the bush forming the inner peripheral surface of the internal gear and the outer peripheral surface of the boss portion of the external gear. It is configured to be arranged and urged by a spring to separate the pair of wedge-shaped members.

With this configuration, when the rotating shaft does not rotate, the pair of wedge-shaped members are fitted between the connecting member and the bush by the urging by the spring, so that the external gear and the internal gear are The relative rotation with and is regulated, and the tilt angle of the seat back with respect to the seat cushion is maintained. On the other hand, when the rotating shaft rotates, the frictional force received from the connecting member that rotates with the rotating shaft causes one wedge-shaped member to escape from the wedge space in which the wedge-shaped member is fitted, thereby releasing the regulation by the wedge-shaped member. .. As a result, the external gear and the internal gear rotate relative to each other according to the rotation of the rotating shaft, so that the seat back tilts with respect to the seat cushion.

Japanese Unexamined Patent Publication No. 2011-207253

By the way, in the above-described configuration, the U-shaped connecting member needs to be formed so that the thickness in the radial direction becomes thicker toward the tip side at the portion in contact with the wedge-shaped member. When the rotation shaft rotates, the wedge-shaped member receives the frictional force from the outer peripheral surface side by the U-shaped connecting member, and the frictional force that tries to prevent the rotation due to the frictional force from the outer peripheral surface side is removed. It will be received from the inner peripheral surface side that is in contact with the boss portion of the tooth gear. Since the pair of wedge-shaped members, the U-shaped connecting member, and the boss portion of the external gear are all made of the same metal, the frictional force from the outer peripheral surface side and the frictional force from the inner peripheral surface side are almost the same. Therefore, if the thickness of the U-shaped connecting member in the radial direction is constant, it becomes difficult for the wedge-shaped member to rotate smoothly. Therefore, by forming the U-shaped connecting member so that the thickness in the radial direction becomes thicker toward the tip side, the contact portion between the U-shaped connecting member and the wedge-shaped member becomes smaller toward the tip side. Since a large pressure angle is generated, it is possible to generate a force for rotating the wedge-shaped member when the rotation shaft is rotated.

However, since the U-shaped connecting member is formed so that the thickness in the radial direction becomes thicker toward the tip side, it is necessary to adopt a processing method such as precision punching or forging of a thick plate, and the shape is complicated. Therefore, not only is it difficult to reduce the manufacturing cost, but there is also a problem that the workability is poor.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to rotate a pair of cams according to the rotation of a rotating shaft by using a connecting member having a constant radial thickness. It is to provide a possible configuration.

In order to achieve the above object, the invention of claim 1 described in the claims is
A reclining device (20) for the seat (10) that holds the seat back (12) tiltably with respect to the seat cushion (11).
A first frame (21) fixed to one of the seat cushion and the seat back, and a second frame (22) fixed to the other.
External tooth gears (23) connected to the first frame to form external teeth (23a) on the outer peripheral surface and to which resin bushes (23b) constituting the inner peripheral surface are assembled.
An internal tooth (24c) that is connected to the second frame and can mesh with the external tooth and has a larger number of teeth than the external tooth is formed, and a cylindrical portion (24e) facing the internal tooth on the outer peripheral surface. ) Is formed on the internal gear (24),
Rotation axis (25) and
A metal connecting member (28) having a constant radial thickness and sliding with respect to the outer peripheral surface of the cylindrical portion as the rotating shaft rotates by being connected to the rotating shaft.
A pair of metal cams (31a, 31b) that are formed in a wedge shape so that the thickness in the radial direction becomes thinner toward the tip side and are interposed between the connecting member and the bush so that the tip sides are separated from each other. )When,
An urging member (29) that urges the pair of cams to separate from each other.
It is characterized by having.
The reference numerals in the parentheses indicate the correspondence with the specific means described in the embodiments described later.

In the invention of claim 1, a metal connecting member having a constant radial thickness and sliding with respect to the outer peripheral surface of the cylindrical portion of the internal gear as the rotating shaft rotates, and a diameter toward the tip side. A pair of metals that are formed in a wedge shape so that the thickness in the direction becomes thin, and are inserted between the connecting member and the resin bush that constitutes the inner peripheral surface of the external gear so that the tip sides are separated from each other. And an urging member that urges the pair of cams to separate from each other.

As a result, when the rotating shaft does not rotate, the pair of cams are fitted into the wedge space composed of the connecting member and the bush by the urging by the urging member, so that the rotating shaft does not rotate outside. The relative rotation between the tooth gear and the internal gear is regulated. On the other hand, when the rotating shaft rotates in one direction, one cam receives a frictional force along the urging direction by the urging member due to the connecting member rotating together with the rotating shaft, and the other cam is caused by the urging member. It receives frictional force from the inner peripheral surface side so as to resist the urging direction. At that time, the other cam receives a frictional force that tends to prevent rotation due to the frictional force from the inner peripheral surface side from the outer peripheral surface side in contact with the bush. Since the connecting member and the pair of cams are made of metal and the bush is made of resin, the frictional force from the inner peripheral surface side (force to rotate) is the frictional force from the outer peripheral surface side (force to prevent rotation). ), So that the other cam can be rotated against the urging by the urging member. Further, when the rotating shaft rotates in the opposite direction, one cam can be rotated against the urging by the urging member by the connecting member that rotates together with the rotating shaft. Therefore, it is possible to realize a configuration in which a pair of cams can be rotated according to the rotation of the rotating shaft by using a connecting member having a constant radial thickness.

According to the second aspect of the present invention, the connecting member is formed with a concave portion recessed in the axial direction, and the cam is formed with a convex portion that enters so as to interpose a predetermined gap with respect to the concave portion. As a result, when the cam rotates together with the connecting member due to the frictional force from the inner peripheral surface side via the connecting member, the concave portion and the convex portion that has entered the concave portion rotate together so as to maintain a gap. Even if the rotation of the cam and the connecting member is temporarily deviated, the edge of the concave portion contacts the convex portion, so that the contact state between the concave portion and the convex portion is maintained so that the cam and the connecting member are maintained. And can be rotated together.

It is a side view which conceptually shows an example of the vehicle seat which carries the reclining device of this invention. It is a side view of the reclining device. It is an exploded perspective view of the reclining device of FIG. It is a perspective view of the connecting member. 5 (A) is a front view of the connecting member of FIG. 4, and FIG. 5 (B) is a side view of the connecting member of FIG. It is a perspective view of a pair of cams. 7 (A) is a front view of one cam of FIG. 6, and FIG. 7 (B) is a side view of one cam of FIG. FIG. 2 is a cross-sectional view taken along the cut surface corresponding to the X1-X1 line shown in FIG. FIG. 2 is a cross-sectional view of a cut surface corresponding to the X2-X2 line shown in FIG. It is explanatory drawing explaining the relationship between the frictional force from the inner peripheral surface side and the frictional force from the outer peripheral surface side which a cam receives when a connecting member rotates. FIG. 5 is a cross-sectional view illustrating a state in which a shaft, a connecting member, a pair of cams, and an external gear are rotated from the state shown in FIG.

[First Embodiment]
Hereinafter, an embodiment of a vehicle seat 10 equipped with the reclining device 20 according to the present invention will be described with reference to the drawings.
As shown in FIG. 1, the vehicle seat 10 provided with the reclining device 20 of the present invention has a seat cushion 11 that receives the seat portion of the seated person and a seat cushion 11 that can be tilted with respect to the seat cushion 11 and the back portion of the seated person. It is equipped with a seat back 12 that receives.

The seat cushion frame 11a, which is the skeleton of the seat cushion 11, and the seat back frame 12a, which is the skeleton of the seat back 12, are the first frame 21 and the second frame of the reclining device 20 installed at the end of the seat cushion frame 11a. It is connected via 22 and the like. Then, the seat back 12 can be tilted with respect to the seat cushion 11 in response to the rotational drive of the tilting motor (not shown) provided in the reclining device 20.

Next, the configuration of the reclining device 20 will be described with reference to the drawings.
As shown in FIGS. 2 and 3, in addition to the above-mentioned both frames 21 and 22, the reclining device 20 includes an external gear 23, an internal gear 24, a shaft 25, a plate cover 26, a shaft cover 27, and a connecting member 28. , A spring 29 and a pair of cams 31a, 31b. In FIG. 2, for convenience of explanation, the description of both frames 21 and 22 is omitted.

As shown in FIG. 3, the external tooth gear 23 is formed in a substantially annular shape, and external teeth 23a are formed on the outer peripheral surface thereof. Further, a cylindrical resin bush 23b having a small friction coefficient is fitted into the inner peripheral surface of the external gear 23 in order to have excellent wear resistance and reduce the frictional force at the contact portion of the cams 31a and 31b. It has been. That is, the resin bush 23b forming the inner peripheral surface is assembled to the external gear 23. Further, on the side surface of the external gear 23 on the first frame 21 side, four substantially arc-shaped protrusions 23c for assembling to the first frame 21 are provided.

As shown in FIG. 3, the internal gear 24 has an outer cylinder portion 24a in which internal teeth 24c are formed on the inner peripheral surface and a side plate portion in which a cylindrical inner cylinder portion 24e centered on a through hole 24d is formed. It is equipped with 24b. The internal teeth 24c are formed so that the number of teeth is larger than that of the external teeth 23a so as to eccentrically mesh with the external teeth 23a. Specifically, for example, when the number of external teeth 23a is set to 32, the number of internal teeth 24c is set to 33.

Further, the width (axial length) of the internal teeth 24c is set to be longer than the width of the external teeth 23a, and the portion on the side plate portion 24b side is the external tooth gear 23 and the internal tooth gear 24. It is formed so as not to mesh with the external teeth 23a at the time of meshing. Further, the side plate portion 24b is provided with three substantially arcuate protrusions 24f for fixing the internal gear 24 to the second frame 22. The inner cylinder portion 24e can correspond to an example of the “cylindrical portion”.

As shown in FIG. 3, the shaft 25 is a rotating shaft made of resin, and is formed so as to be coaxial with the inner cylinder portion 24e of the internal gear 24 and rotatably fit. The shaft 25 is rotated at a predetermined reduction ratio according to the rotational drive of the tilting motor when the seat back 12 is tilted with respect to the seat cushion 11, and the inner surface of the shaft 25 is used for tilting. Serations are formed to connect the rotating members that rotate in response to the rotational drive of the motor. Further, a plurality of engaging protrusions 25a for engaging with the connecting member 28 are provided at the end of the shaft 25 on the first frame 21 side.

The connecting member 28 and the pair of cams 31a and 31b are arranged (inserted) between the bush 23b forming the inner peripheral surface of the external gear 23 and the outer peripheral surface of the inner cylinder portion 24e of the internal gear 24. Then, in a state where the internal gear 24 is eccentric with respect to the external gear 23, a part of the internal tooth 24c is meshed with the external tooth 23a.

As shown in FIGS. 4 and 5, the connecting member 28 is formed by bending a plate material made of metal (for example, SK5) by pressing, and the thickness in the radial direction is constant except for the gap 28a. It is formed so as to have a thin-walled cylindrical shape. The connecting member 28 is formed with a plurality of engaging recesses 28b with which the engaging protrusions 25a of the shaft 25 are engaged on the first frame 21 side, and two recesses 28c are formed on the second frame 22 side. .. The connecting member 28 is formed so as to be slidable with respect to the outer peripheral surface of the inner cylinder portion 24e on the inner peripheral surface.

Since the pair of cams 31a and 31b shown in FIGS. 3 and 6 have symmetrical shapes, the detailed shape of the cams 31a will be described.
As shown in FIGS. 6 and 7, the cam 31a is a wedge-shaped member made of metal (for example, SCM415), and the thickness in the radial direction is increased toward the tip end side except for the convex portion 32 provided at the tip end portion. It is formed in a wedge shape so as to be thin. For example, as shown in FIG. 7A, the radial thickness t1 of the distal end side portion of the cam 31a is thinner than the radial thickness t2 of the proximal end side (anti-tip side) portion of the cam 31a. ing. The convex portion 32 enters the concave portion 28c of the connecting member 28 through a gap in the insertion state described later, and is formed so that the length in the circumferential direction is shorter than the concave portion 28c. A groove 33 for receiving an urging force from a spring 29 that functions as an urging member is provided on the end surface of the cam 31a on the base end side.

The connecting member 28 and the pair of cams 31a and 31b configured in this way have the bush 23b of the external gear 23 in the meshed state as shown in FIGS. 8 and 9 with the convex portion 32 inserted into the concave portion 28c. It is inserted between the inner tooth gear 24 and the outer peripheral surface of the inner cylinder portion 24e of the internal gear 24. Then, the pair of cams 31a and 31b are urged by the spring 29 in a direction in which they are separated from each other. Further, as shown in FIG. 8, the connecting member 28 is engaged with the engaging projection 25a of the shaft 25 at the engaging recess 28b, and is in a state of being rotatable together with the shaft 25.

In this inserted state, the axial movement of the external gear 23 is restricted by welding the plate cover 26 to the end of the outer cylinder portion 24a of the internal gear 24 in the meshed state. Then, with the shaft 25 and the like positioned by the shaft cover 27, the external gear 23 is welded and fixed to the first frame 21 using the protrusion 23c, and the internal gear 24 is seconded using the protrusion 24f. By welding and fixing to the frame 22, the assembly of the reclining device 20 is completed.

Next, the characteristic configuration of the present embodiment will be described with reference to FIGS. 9 to 11.
In the insertion state as described above, as shown in FIG. 9, the connecting member 28 is in surface contact with the outer peripheral surface of the inner cylinder portion 24e on the inner peripheral surface, and the pair of cams 31a and 31b are attached from the spring 29. By receiving the force, they come into surface contact with the bush 23b on the outer peripheral side and surface contact with the connecting member 28 on the inner peripheral side, respectively.

In such a contact state, when the shaft 25 does not rotate, the pair of cams 31a and 31b are fitted into the wedge space formed by the connecting member 28 and the bush 23b by the biasing by the spring 29, respectively. The relative rotation between the external gear 23 and the internal gear 24 when the 25 does not rotate is restricted.

On the other hand, as shown in FIG. 10, when the shaft 25 rotates in the arrow S direction, the cam 31b receives a frictional force along the urging direction by the spring 29 by the connecting member 28 that rotates together with the shaft 25. , The cam 31a receives a frictional force F1 from the inner peripheral surface side so as to oppose the urging direction by the spring 29. At that time, the cam 31a receives a frictional force F2 that tends to prevent rotation by the frictional force F1 from the inner peripheral surface side from the outer peripheral surface side in contact with the bush 23b.

Since the connecting member 28 and the pair of cams 31a and 31b are made of metal and the bush 23b is made of resin having a small friction coefficient, the frictional force (force to rotate) F1 from the inner peripheral surface side is increased. It also increases due to the frictional force (force that hinders rotation) F2 from the outer peripheral surface side. Therefore, even if the connecting member 28 has a constant radial thickness, the cam 31a can be rotated against the urging by the spring 29 so as to escape from the wedge space in which the cam 31a is fitted. As a result, as shown in FIG. 11, the external gear 23 that receives the frictional force in the rotational direction from the cam 31b that rotates together with the connecting member 28 can be rotated in the arrow S direction together with the cam 31a and the cam 31b.

Further, when the shaft 25 rotates in the direction opposite to the arrow S, the connecting member 28 rotating together with the shaft 25 urges the cam 31b by the spring 29 so as to escape from the wedge space in which the cam 31b is fitted. Can be rotated in the opposite direction as described above.

As described above, in the reclining device 20 according to the present embodiment, the thickness in the radial direction is constant, and the internal gear 24 slides with respect to the outer peripheral surface of the inner cylinder portion 24e as the shaft 25 rotates. The metal connecting member 28 is formed in a wedge shape so that the thickness in the radial direction becomes thinner toward the tip side, and constitutes the inner peripheral surface of the connecting member 28 and the external gear 23 so that the tip side is separated from each other. A pair of metal cams 31a and 31b inserted between the bush 23b made of resin and a spring 29 for urging the pair of cams 31a and 31b in a direction to separate them from each other are provided.

With this configuration, even if the connecting member 28 has a constant radial thickness, the cam 31a or the cam 31b resists the urging by the spring 29 so as to escape from the wedge space in which the cam 31a or the cam 31b is fitted. Can be rotated. Therefore, the connecting member 28 can be formed by a processing method such as press working, which has good workability and is inexpensive.

In particular, since the connecting member 28 is formed to have a constant radial thickness, the wedge-shaped cams (31a, 31b) are formed so that the radial thickness becomes thicker toward the tip side. ), Since the frictional force generated with the) is less likely to vary, the rotation of the external gear 23 becomes smooth, and the behavior of the seat cushion 11 at the time of tilting can be further stabilized.

Further, the connecting member 28 is formed with two recesses 28c dented in the axial direction on the side of the second frame 22, and the pair of cams 31a and 31b are inserted so as to interpose a predetermined gap with respect to the recess 28c. The convex portions 32 are formed respectively.

As a result, when the cam 31a (31b) rotates together with the connecting member 28 due to the frictional force F1 from the inner peripheral surface side via the connecting member 28, the concave portion 28c and the convex portion 32 that has entered the concave portion 28c are formed. They rotate together to maintain a gap (see FIG. 11). Even if the rotation of the cam 31a (31b) and the connecting member 28 is temporarily deviated, the edge of the concave portion 28c comes into contact with the convex portion 32, so that the contact state between the concave portion 28c and the convex portion 32 is maintained. The cam 31a (31b) and the connecting member 28 can be rotated together in such a manner.

[Other Embodiments]
The present invention is not limited to the above-described embodiment and modifications, and may be embodied as follows, for example.
(1) The connecting member 28 and the shaft 25 are not limited to being connected so as to rotate coaxially by engaging the engaging recess 28b and the engaging protrusion 25a, and have other shapes, for example, the connecting member 28. The convex portion formed on the shaft 25 may be connected so as to rotate coaxially by fitting the concave portion formed on the shaft 25 or the like.

(2) The first frame 21 is not limited to being connected to the seat cushion frame 11a and the second frame 22 to the seat back frame 12a, but the first frame 21 is connected to the seat back frame 12a and the first frame 21 is connected to the seat back frame 12a. The two frames 22 may be connected to the seat cushion frame 11a. Further, the first frame 21 and the second frame 22 may be a part of the seat cushion frame 11a and the seat back frame 12a.

10 ... Vehicle seat 11 ... Seat cushion 12 ... Seat back 20 ... Reclining device 21 ... 1st frame 22 ... 2nd frame 23 ... External tooth gear 23a ... External tooth 23b ... Bush 24 ... Internal tooth gear 24c ... Internal tooth 24e ... Inner cylinder part (cylindrical part)
25 ... Shaft (rotating shaft)
28 ... Connecting member 28c ... Recessed portion 29 ... Spring (biasing member)
31a, 31b ... Cam 32 ... Convex part

Claims (2)

A seat reclining device that holds the seat back tiltably with respect to the seat cushion.
A first frame fixed to one of the seat cushion and the seat back, a second frame fixed to the other, and
External tooth gears that are connected to the first frame to form external teeth on the outer peripheral surface and to which resin bushes constituting the inner peripheral surface are assembled.
An internal tooth that is connected to the second frame and can mesh with the external tooth and has a larger number of teeth than the external tooth is formed, and a cylindrical portion that faces the internal tooth on the outer peripheral surface is formed. Tooth gears and
Rotation axis and
A metal connecting member having a constant radial thickness and being connected to the rotating shaft so as to slide with respect to the outer peripheral surface of the cylindrical portion as the rotating shaft rotates.
A pair of metal cams that are formed in a wedge shape so that the thickness in the radial direction becomes thinner toward the tip side and are inserted between the connecting member and the bush so that the tip sides are separated from each other.
An urging member that urges the pair of cams to separate from each other,
A reclining device characterized by being equipped with. The connecting member is formed with a recess that is dented in the axial direction.
The reclining device according to claim 1, wherein the cam is formed with a convex portion that enters the concave portion so as to interpose a predetermined gap.

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