JP7479305B2 - Reclining device - Google Patents

Description

The present invention relates to a reclining device.

The present inventor has a seat reclining device that holds a seat back tiltably relative to a seat cushion,
a first frame fixed to one of a seat cushion and a seat back, and a second frame fixed to the other of the seat cushion and the seat back;
an externally toothed gear connected to the first frame, the externally toothed gear having an outer peripheral surface on which external teeth are formed and an externally toothed boss portion on an inner peripheral surface which is coaxial with the axial direction;
an internal gear connected to the second frame, the internal gear having an outer circumferential surface formed with internal teeth capable of meshing with the external teeth, and the internal gear having an inner circumferential surface formed with a cylindrical boss portion coaxial with the axial direction;
a rotation shaft that is coaxially and rotatably fitted to the external gear and that causes one of the external gear and the internal gear to revolve around a gear shaft of the other external gear,
a pair of wedge-shaped cams that are interposed between the cylindrical boss portion and the external tooth boss portion, and that simultaneously contact the cylindrical boss portion side and the external tooth boss portion to regulate rotation between the cylindrical boss portion and the external tooth boss portion, and that slide at least one of the cylindrical boss portion side and the external tooth boss portion side to allow rotation between the cylindrical boss portion and the external tooth boss portion;
a spring member for biasing the pair of wedge-shaped cams in a direction to simultaneously contact the cylindrical boss portion side and the external tooth boss portion side;
a disk-shaped member that rotates with the rotation of the rotary shaft, the disk-shaped member extending in the axial direction and including a pair of cam pushing blades having tapered contact surfaces that push the pair of wedge-shaped cams in a direction away from at least one of the cylindrical boss portion side and the external tooth boss portion side;
Patent Document 1 proposes a leaf spring that presses the disk-shaped member against the pair of wedge-shaped cams and abuts the tapered abutment surface against the pair of wedge-shaped cams, the spring force of which is set to be weaker than that of the spring material.

This reclining device has the effect that the wedge-shaped cam is directly operated by the cam pusher blade of the disk-shaped member that is linked to the rotating shaft, which makes the rotational resistance between the external gear and the internal gear uniform, making it possible to smoothly rotate the external gear and the internal gear.

In this type of reclining device, only the wedge-shaped cam abuts against the bush, so when a large force is applied to the seat back of the vehicle seat, the reclining device can only receive the external force at the contact point between the bush and the wedge-shaped cam. This means that depending on the direction of the external force, a large force may be applied to one part, and for example, the force may have to be received by gear teeth. When the force is received by gear teeth in this way, the reclining device, which is a differential gear, may not be able to slide and rotate smoothly.

JP 2019-127210 A

The present invention was made in consideration of these problems, and aims to provide a reclining device that allows the bush to support the entire circumference, and can stabilize the sliding movement by receiving external forces from any direction within 360° through the bush.

To achieve the above-mentioned objectives, the present invention adopts the following measures.

The reclining device of the present invention comprises:
A seat reclining device that holds a seat back frame that constitutes a seat back so as to be tiltable relative to a seat cushion frame that constitutes a seat cushion,
an externally toothed gear attached directly or indirectly to one of the seat cushion frame and the seat back frame, the externally toothed gear having external teeth formed on an outer peripheral surface and a through hole formed coaxially with the axial direction on an inner peripheral surface;
an internal gear that is directly or indirectly attached to the other of the seat cushion frame and the seat back frame, that has internal teeth on an inner circumferential surface that are at least one more than the external teeth and that can mesh with the external teeth, and that has a cylindrical boss that is coaxial with the axial direction;
a rotating shaft that is coaxially and rotatably inserted into the cylindrical boss of the internal gear and rotates either the external gear or the internal gear around a gear axis of the other gear;
a first bush that is disposed between an inner periphery of the through hole of the external gear and an outer periphery of the cylindrical boss of the internal gear and is formed in an annular shape with the center of the outer periphery and the center of the inner periphery being eccentric; and a second bush that has the same outer periphery and inner periphery as the first bush, is attached to the first bush so as to rotate in the same manner as the first bush, and has a cam accommodating portion on its inner periphery, and rotates with the rotation of the rotating shaft;
a pair of wedge-shaped cams that are accommodated in the cam accommodating portion and press the cylindrical boss of the internal gear and the bush to bring the bush into contact with the inner circumferential surface of the through hole of the external gear, thereby restricting the relative rotation between the external gear and the internal gear, and that rotate the rotating shaft to slide the bush against the outer circumferential surface of the cylindrical boss of the internal gear or the bush against the inner circumferential surface of the through hole of the external gear, thereby allowing the relative rotation between the external gear and the internal gear;
an elastic body that biases the pair of wedge-shaped cams in a direction to simultaneously contact the bush and the cylindrical boss,
The gap between the cylindrical boss of the internal gear and the bush is larger than the gap between the through hole of the external gear and the bush.

The first bush is in contact with the cylindrical boss over its entire circumference, and is also in contact with the through hole of the external gear, so it can support the entire circumference. Therefore, even if an external force is applied from any direction within 360°, the force can be received by the first bush, and the sliding between the bush and the internal gear or between the bush and the external gear can be stabilized. Furthermore, by dividing the bush, the workability of the bush can be improved. Also, the cam can be made thinner.

In addition, in the reclining device according to the present invention,
A seat reclining device that holds a seat back frame that constitutes a seat back so as to be tiltable relative to a seat cushion frame that constitutes a seat cushion,
an externally toothed gear attached directly or indirectly to one of the seat cushion frame and the seat back frame, the externally toothed gear having external teeth formed on an outer peripheral surface and a through hole formed coaxially with the axial direction on an inner peripheral surface;
an internal gear that is directly or indirectly attached to the other of the seat cushion frame and the seat back frame, that has internal teeth that are at least one more than the external teeth on an inner circumferential surface and that can mesh with the external teeth, and that has a cylindrical boss that is coaxial with the axial direction;
a rotating shaft that is coaxially and rotatably inserted into a cylindrical boss of the internal gear and rotates either the external gear or the internal gear around a gear axis of the other gear;
a first bush that is disposed between an inner periphery of the through hole of the external gear and an outer periphery of the cylindrical boss of the internal gear and is formed in an annular shape with the center of the outer periphery and the center of the inner periphery being eccentric; and a second bush that has the same outer periphery and inner periphery as the first bush, is attached to the first bush so as to rotate in the same manner as the first bush, and has a cam accommodating portion on its outer periphery, and rotates with the rotation of the rotating shaft;
a pair of wedge-shaped cams that are accommodated in the cam accommodating portion and press the through hole of the external gear and the bush to bring the bush into contact with the outer circumferential surface of the cylindrical boss of the internal gear, thereby restricting relative rotation between the external gear and the internal gear, and that rotate the rotating shaft to slide the bush against the outer circumferential surface of the cylindrical boss of the internal gear or the bush against the inner circumferential surface of the through hole of the external gear, thereby allowing relative rotation between the external gear and the internal gear;
an elastic body that biases the pair of wedge-shaped cams in a direction to simultaneously contact the bush and the through hole of the external gear,
A gap between the cylindrical boss of the internal gear and the bush is smaller than a gap between the through hole of the external gear and the bush.

In the configuration of this reclining device, the first bush is in contact with the cylindrical boss over its entire circumference, and is also in contact with the through hole of the external gear, so it can support the entire circumference. Therefore, even if an external force is applied from any direction within 360°, the force can be received by the first bush, and the sliding between the bush and the internal gear or between the bush and the external gear can be stabilized. Furthermore, by dividing the bush, the workability of the bush can be improved. Also, the cam can be made thinner.

Further, the present invention provides a reclining device for a seat that holds a seat back frame constituting a seat back so as to be tiltable relative to a seat cushion frame constituting a seat cushion, the reclining device comprising:
an external gear attached directly or indirectly to one of the seat cushion frame and the seat back frame, the external gear having external teeth formed on an outer circumferential surface and a cylindrical boss coaxial with an axial direction;
an internal gear that is directly or indirectly attached to the other of the seat cushion frame and the seat back frame, that has internal teeth on an inner circumferential surface that are at least one more than the external teeth and that can mesh with the external teeth, and that has a through hole formed coaxially in the axial direction on the inner circumferential surface;
a rotating shaft that is coaxially and rotatably inserted into the cylindrical boss of the external gear and rotates either the external gear or the internal gear around a gear axis of the other gear;
a first bush that is disposed between an outer periphery of the cylindrical boss of the external gear and an inner periphery of the through hole of the internal gear and is formed in an annular shape with the center of the outer periphery and the center of the inner periphery being eccentric; and a second bush that has the same outer periphery and inner periphery as the first bush, is attached to the first bush so as to rotate in the same manner as the first bush, and has a cam accommodating portion on its inner periphery, and rotates with the rotation of the rotating shaft;
a pair of wedge-shaped cams that are accommodated in the cam accommodating portion and press the cylindrical boss of the external gear and the bush to bring the bush into contact with the inner circumferential surface of the through hole of the internal gear, thereby restricting the relative rotation between the external gear and the internal gear, and that rotate the rotating shaft to slide the bush against the outer circumferential surface of the cylindrical boss of the external gear or the bush against the inner circumferential surface of the through hole of the internal gear, thereby allowing the relative rotation between the external gear and the internal gear;
an elastic body that biases the pair of wedge-shaped cams in a direction to simultaneously contact the bush and the cylindrical boss,
A gap between the through hole of the internal gear and the bush is smaller than a gap between the cylindrical boss of the external gear and the bush.

Further, the present invention provides a reclining device for a seat that holds a seat back frame constituting a seat back so as to be tiltable relative to a seat cushion frame constituting a seat cushion, the reclining device comprising:
an external gear attached directly or indirectly to one of the seat cushion frame and the seat back frame, the external gear having external teeth formed on an outer circumferential surface and a cylindrical boss coaxial with an axial direction;
an internal gear that is directly or indirectly attached to the other of the seat cushion frame and the seat back frame, that has internal teeth on an inner circumferential surface that are at least one more than the external teeth and that can mesh with the external teeth, and that has a through hole formed coaxially in the axial direction on the inner circumferential surface;
a rotating shaft that is coaxially and rotatably inserted into the cylindrical boss of the external gear and rotates either the external gear or the internal gear around a gear axis of the other gear;
a first bush that is disposed between an outer periphery of a cylindrical boss of the external gear and an inner periphery of the through hole of the internal gear and is formed in an annular shape with the center of the outer periphery and the center of the inner periphery being eccentric; and a second bush that has the same outer periphery and inner periphery as the first bush, is attached to the first bush so as to rotate in the same manner as the first bush, and has a cam accommodating portion on its outer periphery, and rotates with the rotation of the rotating shaft;
a pair of wedge-shaped cams that are accommodated in the cam accommodating portion and press the through hole of the internal gear and the bush to bring the bush into contact with the outer circumferential surface of the cylindrical boss of the external gear, thereby restricting relative rotation between the external gear and the internal gear, and that rotate the rotating shaft to slide the bush and the through hole of the internal gear or the bush and the cylindrical boss of the external gear, thereby allowing relative rotation between the external gear and the internal gear;
an elastic body that biases the pair of wedge-shaped cams in a direction to simultaneously contact the bush and the through hole of the internal gear,
A gap between the through hole of the internal gear and the bush is larger than a gap between the cylindrical boss of the external gear and the bush.

In addition, in the reclining device according to the present invention,
The amount of eccentricity between the center of the bushing relative to the outer circumferential surface and the center of the inner circumferential surface may be equal to or greater than the amount of eccentricity between the center of the internal gear and the center of the external gear.

By setting this range, it is possible to reduce gaps between the external teeth of the external gear and the internal teeth of the internal gear.

FIG. 1 is a schematic diagram of a vehicle seat 200 to which a reclining device 100 according to a first embodiment is attached. FIG. 2 is a front view showing the internal structure of the reclining device 100 according to the first embodiment. FIG. 3 is an exploded perspective view of the reclining device 100 according to the first embodiment. FIG. 4 is a cross-sectional view taken along line AA of FIG. 2 according to the first embodiment. FIG. 5 is a schematic diagram illustrating the bush 40 according to the first embodiment. FIG. 6 is a front view showing the internal structure of the reclining device 100 according to the second embodiment. FIG. 7 is an exploded perspective view of the reclining device 100 according to the third embodiment. FIG. 8 is a front view showing the internal structure of the reclining device 100 according to the third embodiment. FIG. 9 is an exploded perspective view of the reclining device 100 according to the fourth embodiment. FIG. 10 is a front view showing the internal structure of the reclining device 100 according to the fourth embodiment.

The reclining device 100 according to an embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a schematic diagram of a vehicle seat 200, FIG. 2 is a front view showing the internal structure of the reclining device 100, FIG. 3 is an exploded perspective view of the reclining device 100, and FIG. 4 is a cross-sectional view taken along line A-A in FIG. 2. Note that the embodiments and drawings described below are intended to exemplify some of the embodiments of the present invention, and are not to be used for the purpose of limiting the present invention to these configurations. Note that corresponding components in each drawing are denoted by the same or similar reference numerals.

As shown in FIG. 1, the reclining device 100 of the present invention is a device that is attached to a seat cushion 210 of a vehicle seat 200 and a seat back 220 that is tiltably attached to the seat cushion 210 at a central position of the seat back's tilt, and provides a tilting function to the seat back 220. Specifically, the reclining device 100 is used by being attached directly between a seat cushion frame arranged inside the seat cushion 210 and a seat back frame arranged inside the seat back 220, or indirectly via another attachment plate 230 (hereinafter referred to as "attachment plate, etc.").

As shown in Figure 2 or Figure 3, the reclining device 100 according to the present invention mainly comprises an external gear 10, an internal gear 20, a rotating shaft 30, a bush 40, a pair of wedge-shaped cams 50a, 50b (50), a spring 60 as an elastic body, a spring cover 70, and a plate cover 80. Note that in Figure 2, the spring cover 70 and the plate cover 80 are omitted to make the internal structure easier to see.

As shown in FIG. 3, the external gear 10 is formed in a disk shape, with external teeth 11 formed on the outer circumferential surface 10a and a cylindrical through hole 12 formed in the center. The external gear 10 is provided with a protrusion 13, which is attached by welding or the like in a state where it fits into a fitting hole provided in a mounting plate or the like 230.

The internal gear 20 is formed in a disk shape having a diameter larger than that of the external gear 10, and a cylindrical recess is formed so that the external gear 10 can be mounted inside, and the internal teeth 21 are formed on the inner peripheral surface 20a of the recess. The internal teeth 21 are formed at least one more than the number of teeth of the external teeth 11 of the external gear 10, and the external gear 10 and the internal gear 20 are engaged with the internal teeth 21 and the external teeth 11 so that the center _C1 of the external gear 10 and the center _C2 of the internal gear 20 are eccentric, as shown in FIG. 2. Therefore, the external gear 10 and the internal gear 20 form a differential gear, and when the internal gear 20 makes one revolution around the external teeth 11, the rotation proceeds by the difference between the teeth of the internal teeth 21 and the external teeth 11. That is, for example, if there is only one difference in tooth, when the external gear 10 makes one revolution around the internal gear 20, it rotates by one tooth. A cylindrical boss 22 is provided at the center of the internal gear 20. As shown in FIG. 3, the internal gear 20 is provided with a protrusion 23, which is fitted into a fitting hole provided in a mounting plate or the like 230 and is attached by welding or the like.

The rotating shaft 30 is coaxially inserted into the cylindrical boss 22 of the internal gear 20 so as to be freely rotatable. The rotating shaft 30 is rotated when adjusting the tilt of the seat back 220, and has serrations 31 on its inner cylindrical surface to receive the rotational force of the tilt motor. The rotating shaft 30 also has a mating recess 32 that fits with a protrusion 42 provided on a bush 40, which will be described later. The mating recess 32 is attached so as to sandwich the protrusion 42 from both sides, so that the bush 40 rotates in the same way as the rotating shaft 30 whether the rotating shaft 30 is rotated clockwise or counterclockwise.

The bush 40 is an annular or ring-shaped member disposed between the outer peripheral surface 22a of the cylindrical boss 22 of the internal gear 20 and the through hole 12 of the external gear 10. As shown in FIG. 3, the bush 40 has a first bush 40a and a second bush 40b, which are attached by overlapping each other. The first bush 40a is formed with a cylindrical boss hole 41 formed with a diameter substantially equal to that of the outer peripheral surface 22a of the cylindrical boss 22 of the internal gear 20, and an outer peripheral surface 43a formed with a diameter substantially equal to that of the inner peripheral surface 12a of the through hole 12 of the external gear 10, and a cylindrical fitting protrusion 44a that fits with the second bush 40b is provided on the side surface. As shown in FIG. 5, the first bush 40a is formed in a ring shape in which the center _C3 of the inner peripheral surface 41a of the cylindrical boss hole 41 is offset from the center _C4 of the outer peripheral surface 43. On the other hand, the second bush 40b is formed in an annular shape having substantially the same inner and outer diameters as the first bush 40a, and is also formed in an eccentric ring shape with the center _C3 relative to the outer circumferential surface 43 and the center _C4 of the cylindrical boss hole 41 being offset. The second bush 40b is formed with a fitting recess 45b that fits with the fitting protrusion 44a, and is formed to be integrated with the first bush 40a. The second bush 40b is formed with two cam accommodating portions 44 in such a way that the gap between them gradually narrows from the opposing sides in the direction away from each other, in accordance with the shape of the wedge-shaped cam 50 described later. As shown in FIG. 2, the cam accommodating portions 44 are provided on both sides of the thickest portion α of the second bush 40b. The thickest portion has an extension portion 46 that extends toward the outer circumferential surface 22a of the cylindrical boss 22.

2, the cylindrical boss hole 41 of the bush 40 has a diameter slightly larger than the diameter of the outer peripheral surface 22a of the cylindrical boss 22, and a gap A is formed between the cylindrical boss hole 41 and the outer peripheral surface 22a of the cylindrical boss 22. The gap A is preferably set to approximately 0.06 mm to 0.12 mm. The outer peripheral surface 43 of the bush 40 is disposed in the through hole 12 of the external gear 10 and is formed to have a diameter slightly smaller than the diameter of the through hole 12 of the external gear 10, and a gap B is formed between the outer peripheral surface 43 of the bush 40 and the through hole 12 of the external gear 10. The gap B is preferably set to approximately 0.02 mm to 0.06 mm. In this case, in order to mesh the external gear 10 and the internal gear 20, the relationship between the gap A and the gap B needs to be gap A > gap B. That is, the gap A between the cylindrical boss 22 of the internal gear 20 and the bush 40 is set to be larger than the gap B between the through hole 12 of the external gear 10 and the bush 40.

The bush 40 has a protrusion 42 on its side that fits into the aforementioned fitting recess 32. The number and position of the protrusions 42 are not particularly limited. This allows the bush 40 to rotate in sync with the rotation of the rotating shaft 30.

Between the inner peripheral surface of the cylindrical boss hole 41 of the bush 40 and the outer peripheral surface 22a of the cylindrical boss 22 of the internal gear 20, a pair of wedge-shaped cams 50a and 50b (50) are provided so as to contact both. As shown in FIG. 3, the wedge-shaped cams 50a and 50b are formed symmetrically with respect to a plane, and the concave surface 51 (inner surface) of the wedge-shaped cam 50 has the same curved surface as the curved surface of the outer peripheral surface 22a of the cylindrical boss 22, and the convex surface 52 (outer surface) is formed so that the thickness gradually decreases from the opposite side.

As shown in FIG. 3, the spring 60 has an annular portion 61 and ends 62a, 62b that rise up from the annular portion 61 so as to be bent 90 degrees. The ends 62a, 62b are arranged on the end faces of the thick portions of the wedge-shaped cams 50a and 50b, and are biased in the direction in which the wedge-shaped cams 50a and 50b move away from each other. This allows the external gear 10 to be pressed against the internal gear 20 and meshed with it. The spring 60 may be made of other elastic material such as rubber, as long as it is capable of biasing the wedge-shaped cams 50a and 50b.

As shown in FIG. 4, the spring cover 70 is a cover that holds the spring 60 so that it does not come off, and there are no particular limitations on the shape as long as it can hold the spring 60.

The plate cover 80 is made of a metal plate formed into an annular shape and is fixed to the outer end of the internal gear 20 by welding or other means, and has the function of restricting the axial movement of the external gear 10.

The reclining device 100 thus constructed operates as follows. When no force is applied to the rotating shaft 30 and it is not rotating, the pair of wedge-shaped cams 50a and 50b are biased by the spring 60 in the direction of moving apart, and are in contact with the bush 40 and the outer circumferential surface 22a of the cylindrical boss 22 of the internal gear 20. As a result, the relative movement of the internal gear 20 and the external gear 10 is locked, and the seat back 220 is in a locked state.

The reclining device 100 thus constructed operates as follows. When no force is applied to the rotating shaft 30 and it is not rotating, the pair of wedge-shaped cams 50a and 50b are biased by the spring 60 in the direction of moving apart, and are in contact with the bush 40 and the outer circumferential surface 22a of the cylindrical boss 22 of the internal gear 20. As a result, the relative movement of the internal gear 20 and the external gear 10 is locked, and the seat back 220 is in a locked state.

When the rotating shaft 30 is rotated counterclockwise from this locked state, for example in FIG. 2, the bush 40 engaged with the rotating shaft 30 also rotates. A wedge angle is set on the inner wall of the cam accommodating portion 44 of the bush 40, and the wedge angle inner wall is in contact with the wedge-shaped cam 50. When the bush 40 rotates, a gap is generated between the wedge angle inner wall and the wedge-shaped cam 50, and the wedge is removed. The rotating shaft 30 and the bush 40 rotate counterclockwise relative to the internal gear 20, and as a result, a gap is generated between the bush 40 and the cylindrical boss 22 and between the bush 40 and the through hole 12 of the external gear 10, and the external gear 10 becomes rotatable relative to the internal gear 20. Accordingly, the wedge-shaped cam 50a rotates counterclockwise to fill the gap due to the biasing force of the spring 60. The wedge-shaped cam 50 rotates counterclockwise to slide together with the rotating shaft 30 and the bush 40. In this way, the external gear 10, the internal gear 20, and the rotating shaft 30 form a differential gear mechanism. Clockwise rotation can also be achieved in the same way.

In the reclining device 100 thus manufactured, the first bush 40a of the bushes 40 is formed in a ring shape around its entire circumference. When an external force is applied to the internal gear 20 or the external gear 10, the internal gear 20 or the external gear 10 tries to move in the direction of the external force or the reaction force. However, the bush is sandwiched perpendicularly to the outer circumferential surface 22a of the cylindrical boss 22 of the internal gear 20 and the through hole 12 of the external gear 10 in the direction of the movement, and the component force components are minimized to act as a bearing, stabilizing the sliding and ensuring smooth rotation. In addition, by dividing the bush 40, the workability of the bush 40 can be improved. In addition, the wedge-shaped cam 50 can be made thinner.

Second Embodiment
The reclining device 100 according to the second embodiment is shown in Fig. 6. The reclining device 100 according to the second embodiment is similar to the first embodiment except for the bush 40, so the description thereof will be omitted.

In the second embodiment, the second bush 40b has a cam accommodating portion 44 formed on the outer circumferential surface 43 of the second bush 40b such that the gap gradually narrows from the opposing side, and the wedge-shaped cam 50 is inserted into this cam accommodating portion 44. That is, in the first embodiment, the cam accommodating portion 44 is formed on the inner circumferential side of the second bush 40b, whereas in the second embodiment, the cam accommodating portion 44 is formed on the outer circumferential side of the second bush 40b. In the locked state, a gap A is formed between the inner periphery of the cylindrical boss hole 41 and the outer circumferential surface 22a of the cylindrical boss 22, and a gap B is formed between the through hole 12 of the external gear 10 and the bush 40. In the second embodiment, the relationship between the gap A between the inner periphery of the cylindrical boss hole 41 and the outer circumferential surface 22a of the cylindrical boss 22 and the gap B between the through hole 12 of the external gear 10 and the bush 40 must be gap A < gap B. That is, the gap A between the cylindrical boss 22 of the internal gear 20 and the inner circumference of the cylindrical boss hole 41 is set to be smaller than the gap B between the through hole 12 of the external gear 10 and the bush 40.

In the reclining device 100 according to the second embodiment, when no force is applied to the rotating shaft 30 and the rotating shaft 30 is not rotating, the pair of wedge-shaped cams 50a and 50b are biased by the spring 60 in the direction of moving apart, and are in contact with the bush 40 and the inner circumferential surface 12a of the through hole 12 of the external gear 10. Therefore, the relative movement of the internal gear 20 and the external gear 10 is locked, and the seat back 220 is in a locked state.

When the rotating shaft 30 is rotated counterclockwise from this locked state, the bush 40 engaged with the rotating shaft 30 also rotates. In addition, a wedge angle is set on the inner wall of the cam accommodating portion 44 of the bush 40, and the wedge angle inner wall is in contact with the wedge-shaped cam. This rotation creates a gap between the wedge angle inner wall and the wedge-shaped cam 50, and the wedge is removed. The rotating shaft 30 and the bush 40 rotate counterclockwise relative to the internal gear 20, and as a result, a gap is created between the bush 40 and the cylindrical boss 22 and between the bush 40 and the through hole 12 of the external gear 10, and the external gear 10 becomes rotatable relative to the internal gear 20. Accordingly, the wedge-shaped cam 50a rotates counterclockwise to fill this gap due to the biasing force of the spring 60. The wedge-shaped cam 50 rotates counterclockwise to slide together with the rotating shaft 30 and the bush 40. In this way, the external gear 10, the internal gear 20, and the rotating shaft 30 form a differential gear mechanism. Clockwise rotation can also be achieved in the same way.

In the reclining device 100 thus manufactured, the first bush 40a of the bushes 40 is formed in a ring shape around its entire circumference. When an external force is applied to the internal gear 20 or the external gear 10, the internal gear 20 or the external gear 10 tries to move in the direction of the external force or the reaction force. However, the bush 40 is sandwiched perpendicularly to the outer circumferential surface 22a of the cylindrical boss 22 of the internal gear 20 and the inner circumferential surface 12a of the through hole 12 of the external gear 10 in the direction of the movement, and the component force components are minimized to serve as a bearing, so that sliding is stabilized and smooth rotation can be ensured. In addition, by dividing the bush 40, the workability of the bush 40 can be improved. In addition, the wedge-shaped cam 50 can be made thinner.

Third Embodiment
The reclining device 100 according to the third embodiment is shown in Fig. 7 or Fig. 8. The reclining device 100 according to the third embodiment differs from the reclining device 100 according to the first embodiment in that a cylindrical boss 14 is provided at the center of the external gear 10, and a through hole 25 is provided at the center of the internal gear 20. Also, a restricting cover 70 for preventing the rotating shaft 30, the bush 40, the wedge-shaped cam 50, and the spring 60 from moving in the axial direction is provided on the outer surface side of the internal gear 20, and the restricting cover 70 is provided with a protrusion 71 that fits into a fitting hole of the mounting plate or the like 230. On the other hand, the plate cover 80 is formed of a metal plate formed in an annular shape, is arranged on the outer surface side of the external gear 10, and is fixed to the end of the outer periphery of the internal gear 20 by welding or the like, and restricts the axial movement of the external gear 10.

The rotating shaft 30, the bush 40, and the spring 60 are made symmetrical to those of the first embodiment. The bush 40 is arranged between the outer circumferential surface 14a of the cylindrical boss 14 of the external gear 10 and the through hole 25 of the internal gear 20 so that the cylindrical boss 14 is inserted into the cylindrical boss hole 41 of the bush 40. The rotating shaft 30 is arranged in the cylindrical boss 14 so as to rotate coaxially with the central axis of the cylindrical boss 14, and as in the first embodiment, the protrusions 42 provided on the bush 40 are attached so as to be sandwiched from both sides by the fitting recesses 32, so that the bush 40 rotates in the same manner as the rotating shaft 30 whether the rotating shaft 30 is rotated clockwise or counterclockwise. As in the first embodiment, the bush 40 has a first bush 40a and a second bush 40b, which are attached overlapping each other, as shown in FIG. The first bush 40a is formed with an outer peripheral surface 43a formed with a diameter almost the same as that of the inner peripheral surface of the through hole 25 of the internal gear 20, and an inner peripheral surface 41a formed with a diameter almost the same as that of the outer peripheral surface 14a of the inner cylindrical boss 14 of the external gear 10, and a cylindrical fitting protrusion 44a that fits with the second bush 40b is provided on the side. The second bush 40b is formed with a fitting recess 45b that fits with the fitting protrusion 44a, and is formed to be integrated with the first bush 40a. The inner peripheral surface of the second bush 40b is formed with two cam accommodating portions 44 so that the gap between them gradually narrows from the opposing sides in the direction away from each other, in accordance with the shape of the wedge-shaped cam 50 described later. As shown in FIG. 2, the cam accommodating portions 44 are provided on both sides of the thickest portion α of the second bush 40b. The thickest portion has an extension portion 46 that extends toward the outer peripheral surface 22a of the cylindrical boss 22.

The cylindrical boss hole 41 of the bush 40 has a diameter slightly larger than the diameter of the outer peripheral surface 14a of the cylindrical boss 14, and in the locked state, a gap A' is formed between the cylindrical boss hole 41 and the outer peripheral surface 14a of the cylindrical boss 14. The gap A' between the cylindrical boss hole 41 of the bush 40 and the outer peripheral surface 14a of the cylindrical boss 14 should be set to approximately 0.06 mm to 0.12 mm. The outer peripheral surface 43 of the bush 40 is disposed in the through hole 25 of the internal gear 20 and is formed to have a diameter slightly smaller than the diameter of the through hole 25 of the internal gear 20, and in the locked state, a gap B' is formed between the outer peripheral surface 43 of the bush 40 and the through hole 25 of the internal gear 20. The gap B' between the outer peripheral surface 43 of the bush 40 and the through hole 25 of the internal gear 20 should be set to approximately 0.02 mm to 0.06 mm. In this case, in order to mesh the external gear 10 and the internal gear 20, the relationship between the gap A' and the gap B' needs to be Gap A' > Gap B'. In other words, the gap B' between the through hole 25 of the internal gear 20 and the bush 40 is set to be smaller than the gap A' between the cylindrical boss 14 of the external gear 10 and the bush 40.

The reclining device 100 thus constructed operates as follows. When no force is applied to the rotating shaft 30 and it is not rotating, the pair of wedge-shaped cams 50a and 50b are biased by the spring 60 in the direction of moving apart, and are in contact with the bush 40 and the outer circumferential surface 14a of the cylindrical boss 14 of the external gear 10. As a result, the relative movement of the internal gear 20 and the external gear 10 is locked, and the seat back 220 is in a locked state.

When the rotating shaft 30 is rotated counterclockwise from this locked state, the bush 40 engaged with the rotating shaft 30 also rotates. A wedge angle is set on the inner wall of the cam accommodating portion 44 of the bush 40, and the wedge angle inner wall is in contact with the wedge-shaped cam 50. This rotation creates a gap between the wedge angle inner wall and the wedge-shaped cam 50, and the wedge is removed. The rotating shaft 30 and the bush 40 rotate counterclockwise relative to the internal gear 20, and as a result, a gap is created between the bush 40 and the cylindrical boss 14 and between the bush 40 and the through hole 25 of the internal gear 20, and the external gear 10 becomes rotatable relative to the internal gear 20. Accordingly, the wedge-shaped cam 50a rotates counterclockwise to fill the gap due to the biasing force of the spring 60. The wedge-shaped cam 50 rotates counterclockwise to slide together with the rotating shaft 30 and the bush 40. In this way, the external gear 10, the internal gear 20, and the rotating shaft 30 form a differential gear mechanism. Clockwise rotation can also be achieved in the same way.

In the reclining device 100 thus manufactured, the bush 40 is formed in a ring shape, so when an external force is applied to the internal gear 20 or the external gear 10, the internal gear 20 or the external gear 10 tries to move in the direction of the external force or the reaction force, but the bush 40 is sandwiched perpendicular to the outer circumferential surface 14a of the cylindrical boss 14 of the external gear 10 and the through hole 25 of the internal gear 20 in the direction of the attempted movement, and the component force components are kept to a minimum to function as a bearing, stabilizing the sliding and ensuring smooth rotation.

Fourth Embodiment
A reclining device 100 according to a fourth embodiment is shown in Fig. 9 or 10. The reclining device 100 according to the fourth embodiment is similar to the third embodiment except for the bush 40, so a description thereof will be omitted.

The bush 40 according to the fourth embodiment has a first bush 40a and a second bush 40b, which are attached in an overlapping manner, as shown in FIG. 9, in the same manner as in the third embodiment. The first bush 40a is formed with an outer peripheral surface 43a formed with a diameter substantially the same as that of the inner peripheral surface of the through hole 25 of the internal gear 20, and an inner peripheral surface 41a formed with a diameter substantially the same as that of the outer peripheral surface 14a of the inner cylinder boss 14 of the external gear 10, and a cylindrical fitting protrusion 44a that fits with the second bush 40b is provided on the side. The second bush 40b is formed with a fitting recess 45b that fits with the fitting protrusion 44a, and is formed to be integrated with the first bush 40a. The outer peripheral surface 43a of the second bush 40b is formed with two cam accommodating portions 44 so that the gap between them gradually narrows from the opposing sides in the direction away from each other, in accordance with the shape of the wedge-shaped cam 50 described later. That is, in the third embodiment, the cam housing portion 44 is formed on the inner periphery of the second bushing 40b, whereas in the fourth embodiment, the cam housing portion 44 is formed on the outer periphery of the second bushing 40b.

In the locked state, a gap A' is formed between the cylindrical boss 14 of the external gear 10 and the inner circumferential surface of the bush 40, and a gap B' is formed between the through hole 25 of the internal gear 20 and the bush 40. The relationship between the gap A' between the inner circumferential surface of the cylindrical boss 14 of the external gear 10 and the bush 40 and the gap B' between the through hole 25 of the internal gear 20 and the bush 40 must be gap A' < gap B'. In other words, the gap B' between the through hole 25 of the internal gear 20 and the bush 40 is set to be larger than the gap A' between the cylindrical boss 14 of the external gear 10 and the inner periphery of the cylindrical boss hole 41 of the bush 40.

In the reclining device 100 according to the fourth embodiment, when no force is applied to the rotating shaft 30 and the rotating shaft 30 is not rotating, the pair of wedge-shaped cams 50a and 50b are biased by the spring 60 in the direction in which they move apart, and are in contact with the bush 40 and the inner circumferential surface of the through hole 25 of the internal gear 20. Therefore, the relative movement of the internal gear 20 and the external gear 10 is locked, and the seat back 220 is in a locked state.

When the rotating shaft 30 is rotated counterclockwise from this locked state, the bush 40 engaged with the rotating shaft 30 also rotates. A wedge angle is set on the inner wall of the cam housing portion 44 of the bush 40, and the wedge angle inner wall is in contact with the wedge-shaped cam. This rotation creates a gap between the wedge angle inner wall and the wedge-shaped cam 50, and the wedge is removed. The rotating shaft 30 and the bush 40 rotate counterclockwise relative to the internal gear 20, and as a result, a gap is created between the bush 40 and the cylindrical boss 14 and between the bush 40 and the through hole 25 of the internal gear 20, and the external gear 10 becomes rotatable relative to the internal gear 20. Accordingly, the wedge-shaped cam 50a rotates counterclockwise to fill the gap due to the biasing force of the spring 60. The wedge-shaped cam 50 rotates counterclockwise to slide together with the rotating shaft 30 and the bush 40. In this way, the external gear 10, the internal gear 20, and the rotating shaft 30 form a differential gear mechanism. Clockwise rotation can also be achieved in the same way.

In the reclining device 100 thus manufactured, the bush 40 is formed in a ring shape, so when an external force is applied to the internal gear 20 or the external gear 10, the internal gear 20 or the external gear 10 tries to move in the direction of the external force or the reaction force, but the bush 40 is sandwiched perpendicular to the direction of the attempted movement between the outer circumferential surface 14a of the cylindrical boss 14 of the external gear 10 and the inner circumferential surface of the through hole 25 of the internal gear 20, and the component force components are kept to a minimum to function as a bearing, stabilizing the sliding and ensuring smooth rotation.

In the first to fourth embodiments described above, the bushing 40 may be formed in an annular or ring shape in which the amount of eccentricity γ between the center _C3 relative to the outer circumferential surface 43 of the bushing 40 and the center _C4 of the cylindrical boss hole 41 is larger than the amount of eccentricity β between the center _C1 of the internal gear 20 and the center _C2 of the external gear 10. In other words, the bushing 40 may be formed so that the amount of eccentricity γ is greater than the amount of eccentricity β.

Each component of the reclining device 100 varies depending on the manufacturing process, and a gap A is formed between the cylindrical boss hole 41 and the outer peripheral surface 22a of the cylindrical boss 22, and a gap B is formed between the external gear 10 and the through hole 12, so that a misalignment equivalent to the gap occurs between the external teeth 11 of the external gear 10 and the internal teeth 21 of the internal gear 20. Therefore, by making the amount of eccentricity between the center _C3 and the center C4 of the cylindrical boss hole 41 relative to the outer peripheral surface ₄₃ of the bush 40 greater than or equal to the amount of eccentricity between the center _C1 of the internal gear 20 and the center _C2 of the external gear 10, it is possible to reduce the occurrence of a gap between the external gear 10, the external teeth 11, and the internal teeth 21 of the internal gear 20.

In addition, in the first to fourth embodiments described above, the bush 40 is provided with a protrusion 42, and the rotating shaft 30 is provided with a fitting recess 32, but the bush 40 may be provided with a fitting recess 32, and the rotating shaft 30 may be provided with a protrusion 42.

The present invention is not limited to the above-described embodiment, and may be implemented in various forms within the technical scope of the present invention.

As shown in the above-mentioned embodiment, it can be used industrially primarily as a reclining device for vehicle seats.

10...external gear, 10a...outer peripheral surface, 11...external teeth, 12...through hole, 12a...inner peripheral surface, 13...projection, 14...cylindrical boss, 14a...outer peripheral surface, 20...internal gear, 20a...inner peripheral surface, 21...internal teeth, 22...cylindrical boss, 22a...outer peripheral surface, 23...projection, 25...through hole, 30...rotating shaft, 31...serration, 32...engagement recess, 40...bush, 40a...first bush, 40b...second bush, 41...hole for cylindrical boss, 41a...inner peripheral surface, 42...projection, 43...outer peripheral surface surface, 43a...outer peripheral surface, 44...cam housing portion, 44a...fitting convex portion, 45b...fitting concave portion, 46...extension portion, 50...wedge-shaped cam, 50a...wedge-shaped cam, 50b...wedge-shaped cam, 51...concave surface, 52...convex surface, 60...spring, 61...annular portion, 62a...end portion, 70...spring cover, 71...projection portion, 80...plate cover, 100...recliner, 200...vehicle seat, 210...seat cushion, 220...seat back, 230...mounting plate

Claims (5)

A seat reclining device that holds a seat back frame that constitutes a seat back so as to be tiltable relative to a seat cushion frame that constitutes a seat cushion,
an externally toothed gear attached directly or indirectly to one of the seat cushion frame and the seat back frame, the externally toothed gear having external teeth formed on an outer peripheral surface and a through hole formed coaxially with the axial direction on an inner peripheral surface;
an internal gear that is directly or indirectly attached to the other of the seat cushion frame and the seat back frame, that has internal teeth that are at least one more than the external teeth on an inner circumferential surface and that can mesh with the external teeth, and that has a cylindrical boss that is coaxial with the axial direction;
a rotating shaft that is coaxially and rotatably inserted into the cylindrical boss of the internal gear and rotates either the external gear or the internal gear around a gear axis of the other gear;
a first bush that is disposed between an inner periphery of the through hole of the external gear and an outer periphery of the cylindrical boss of the internal gear and is formed in an annular shape with the center of the outer periphery and the center of the inner periphery being eccentric; and a second bush that has the same outer periphery and inner periphery as the first bush, is attached to the first bush so as to rotate in the same manner as the first bush, and has a cam accommodating portion on its inner periphery, and rotates with the rotation of the rotating shaft;
a pair of wedge-shaped cams that are accommodated in the cam accommodating portion and press the cylindrical boss of the internal gear and the bush to bring the bush into contact with the inner circumferential surface of the through hole of the external gear, thereby restricting the relative rotation between the external gear and the internal gear, and that rotate the rotating shaft to slide the bush against the outer circumferential surface of the cylindrical boss of the internal gear or the bush against the inner circumferential surface of the through hole of the external gear, thereby allowing the relative rotation between the external gear and the internal gear;
an elastic body that biases the pair of wedge-shaped cams in a direction to simultaneously contact the bush and the cylindrical boss,
A reclining device, wherein a gap between the cylindrical boss of the internal gear and the bush is larger than a gap between the through hole of the external gear and the bush. A seat reclining device that holds a seat back frame that constitutes a seat back so as to be tiltable relative to a seat cushion frame that constitutes a seat cushion,
an externally toothed gear attached directly or indirectly to one of the seat cushion frame and the seat back frame, the externally toothed gear having external teeth formed on an outer peripheral surface and a through hole formed coaxially with the axial direction on an inner peripheral surface;
an internal gear that is directly or indirectly attached to the other of the seat cushion frame and the seat back frame, that has internal teeth that are at least one more than the external teeth on an inner circumferential surface and that can mesh with the external teeth, and that has a cylindrical boss that is coaxial with the axial direction;
a rotating shaft that is coaxially and rotatably inserted into a cylindrical boss of the internal gear and rotates either the external gear or the internal gear around a gear axis of the other gear;
a first bush that is disposed between an inner periphery of the through hole of the external gear and an outer periphery of the cylindrical boss of the internal gear and is formed in an annular shape with the center of the outer periphery and the center of the inner periphery being eccentric; and a second bush that has the same outer periphery and inner periphery as the first bush, is attached to the first bush so as to rotate in the same manner as the first bush, and has a cam accommodating portion on its outer periphery, and rotates with the rotation of the rotating shaft;
a pair of wedge-shaped cams that are accommodated in the cam accommodating portion and press the through hole of the external gear and the bush to bring the bush into contact with the outer circumferential surface of the cylindrical boss of the internal gear, thereby restricting relative rotation between the external gear and the internal gear, and that rotate the rotating shaft to slide the bush and the outer circumferential surface of the cylindrical boss of the internal gear or the bush and the inner circumferential surface of the through hole of the external gear, thereby allowing relative rotation between the external gear and the internal gear;
an elastic body that biases the pair of wedge-shaped cams in a direction to simultaneously contact the bush and the through hole of the external gear,
A reclining device, wherein a gap between the cylindrical boss of the internal gear and the bush is smaller than a gap between the through hole of the external gear and the bush. A seat reclining device that holds a seat back frame that constitutes a seat back so as to be tiltable relative to a seat cushion frame that constitutes a seat cushion,
an external gear attached directly or indirectly to one of the seat cushion frame and the seat back frame, the external gear having external teeth formed on an outer circumferential surface and a cylindrical boss coaxial with an axial direction;
an internal gear that is directly or indirectly attached to the other of the seat cushion frame and the seat back frame, that has internal teeth on an inner circumferential surface that are at least one more than the external teeth and that can mesh with the external teeth, and that has a through hole formed coaxially in the axial direction on the inner circumferential surface;
a rotating shaft that is coaxially and rotatably inserted into the cylindrical boss of the external gear and rotates either the external gear or the internal gear around a gear axis of the other gear;
a first bush that is disposed between an outer periphery of the cylindrical boss of the external gear and an inner periphery of the through hole of the internal gear and is formed in an annular shape with the center of the outer periphery and the center of the inner periphery being eccentric; and a second bush that has the same outer periphery and inner periphery as the first bush, is attached to the first bush so as to rotate in the same manner as the first bush, and has a cam accommodating portion on its inner periphery, and rotates with the rotation of the rotating shaft;
a pair of wedge-shaped cams that are accommodated in the cam accommodating portion and press the cylindrical boss of the external gear and the bush to bring the bush into contact with the inner circumferential surface of the through hole of the internal gear, thereby restricting the relative rotation between the external gear and the internal gear, and that rotate the rotating shaft to slide the bush against the outer circumferential surface of the cylindrical boss of the external gear or the bush against the inner circumferential surface of the through hole of the internal gear, thereby allowing the relative rotation between the external gear and the internal gear;
an elastic body that biases the pair of wedge-shaped cams in a direction to simultaneously contact the bush and the cylindrical boss,
A reclining device, wherein a gap between the through hole of the internal gear and the bush is smaller than a gap between the cylindrical boss of the external gear and the bush. A seat reclining device that holds a seat back frame that constitutes a seat back so as to be tiltable relative to a seat cushion frame that constitutes a seat cushion,
an external gear attached directly or indirectly to one of the seat cushion frame and the seat back frame, the external gear having external teeth formed on an outer circumferential surface and a cylindrical boss coaxial with an axial direction;
an internal gear that is directly or indirectly attached to the other of the seat cushion frame and the seat back frame, that has internal teeth on an inner circumferential surface that are at least one more than the external teeth and that can mesh with the external teeth, and that has a through hole formed coaxially in the axial direction on the inner circumferential surface;
a rotating shaft that is coaxially and rotatably inserted into the cylindrical boss of the external gear and rotates either the external gear or the internal gear around a gear axis of the other gear;
a first bush that is disposed between an outer periphery of a cylindrical boss of the external gear and an inner periphery of the through hole of the internal gear and is formed in an annular shape with the center of the outer periphery and the center of the inner periphery being eccentric; and a second bush that has the same outer periphery and inner periphery as the first bush, is attached to the first bush so as to rotate in the same manner as the first bush, and has a cam accommodating portion on its outer periphery, and rotates with the rotation of the rotating shaft;
a pair of wedge-shaped cams that are accommodated in the cam accommodating portion and press the through hole of the internal gear and the bush to bring the bush into contact with the outer circumferential surface of the cylindrical boss of the external gear, thereby restricting relative rotation between the external gear and the internal gear, and that rotate the rotating shaft to slide the bush and the through hole of the internal gear or the bush and the cylindrical boss of the external gear, thereby allowing relative rotation between the external gear and the internal gear;
an elastic body that biases the pair of wedge-shaped cams in a direction to simultaneously contact the bush and the through hole of the internal gear,
A reclining device, wherein a gap between the through hole of the internal gear and the bush is larger than a gap between the cylindrical boss of the external gear and the bush. The reclining device according to any one of claims 1 to 4, characterized in that the amount of eccentricity between the center of the bush relative to the outer peripheral surface and the center of the inner peripheral surface is equal to or greater than the amount of eccentricity between the center of the internal gear and the center of the external gear.

Images