Headrest height adjustment mechanism

Abstract

To provide a headrest height adjustment mechanism enabling downsizing of a headrest, with the height required in the minimum height of the headrest, of the headrest secured.SOLUTION: At a minimum height position P of a headrest 14, a headrest height adjustment mechanism is so set as to restrict downward movement of the headrest 14 at a sub headrest stay 20 side as well as a main headrest stay 18, so as to retain the minimum height position of the headrest 14, with a gap H formed between the headrest 14 and a seat back 12. This configuration can downsize the headrest 14, with the height required in the minimum height position of the headrest 14, of the headrest 14 secured.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a headrest height adjustment mechanism. [Background technology]

[0002] The following Patent Document 1 discloses a technology related to a locking mechanism for a headrest support that engages with a headrest stay. By pressing an unlocking knob provided on the headrest support to push the headrest downward, the headrest can be lowered until the bottom surface of the headrest abuts the top surface of the seatback. In other words, in this prior art, the position where the headrest abuts the seatback is the lowest height of the headrest. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-136770 Summary of the Invention [Problem to be solved by the invention]

[0004] Generally, headrests are made of foam such as urethane foam and are therefore elastically deformable. Therefore, variations in the dimensions of the headrest in the vertical direction of the vehicle occur due to the elastic deformation. Therefore, if the minimum height of the headrest is set so that the position where the headrest abuts the seatback is the minimum height, the minimum height must be set taking into account such variations, which results in the headrest becoming larger.

[0005] In consideration of the above, the present invention aims to provide a headrest height adjustment mechanism that allows the headrest to be made smaller while ensuring the required headrest height at its minimum height. [Means for solving the problem]

[0006] The headrest height adjustment mechanism described in claim 1 includes a main support provided on one of a pair of legs that hang down from the left and right sides in the seat width direction of a headrest provided on the upper side of a seat back and are held by the seat back, the main support being provided on a main headrest stay that is one of the legs and having a locking mechanism that adjusts the height of the headrest together with the main headrest stay and can lock the headrest at a predetermined height, and a sub-headrest stay provided on the other of the pair of left and right legs, the main support being provided on a sub-headrest stay that limits downward movement of the headrest together with the sub-headrest stay with a gap provided between the headrest and the seat back at a minimum height position where the height of the headrest is lowest when the main headrest stay is engaged with the main support, thereby maintaining the minimum height position of the headrest. and a sub-support having a movement limiting mechanism for holding the headrest in place, wherein the locking mechanism includes a plurality of main notch portions that are provided on the main headrest stay and formed along the hanging direction of the main headrest stay, the plurality of main notch portions including a minimum height main notch portion that sets the headrest to the minimum height position and one or more main notch portions that are located lower than the minimum height main notch portion in the hanging direction of the main headrest stay, and the movement limiting mechanism includes sub-notch portions that are provided on the sub-headrest stay, the sub-notch portions including a minimum height sub-notch portion that is formed to be at the same height as the minimum height main notch portion and that does not include a sub-notch portion that is located lower than the minimum height sub-notch portion in the hanging direction of the sub-headrest stay.

[0007] The headrest height adjustment mechanism described in claim 1 includes a main support and a sub-support. A pair of legs hang down from the left and right sides of the headrest in the seat width direction, which are provided above the seat back, and the pair of legs are held by the seat back.

[0008] One of the pair of legs is a main headrest stay, and the other is a sub-headrest stay. The main support is provided on the main headrest stay side and includes a locking mechanism that adjusts the height of the headrest together with the main headrest stay and can lock the headrest at a predetermined height. Meanwhile, the sub-support is provided on the sub-headrest stay side and includes a movement limiting mechanism that, together with the sub-headrest stay, limits the downward movement of the headrest.

[0009] Here, the movement limiting mechanism limits the downward movement of the headrest together with the sub-headrest stay (in a so-called locked state) and maintains the headrest at its lowest height position, where the headrest height is at its lowest when the main headrest stay is engaged with the main support, with a gap provided between the headrest and the seat back.

[0010] In the present invention, by providing a gap between the headrest and the seat back at the lowest height position of the headrest, the size of the headrest can be reduced in the height direction by the amount of the gap, when the lowest height position of the headrest is the same, compared to when no gap is provided between the headrest and the seat back.

[0011] Here, in the present invention, the locking mechanism is provided on the main headrest stay, and a plurality of main notch portions are formed along the hanging direction of the main headrest stay. The plurality of main notch portions include a minimum height main notch portion and one or more main notch portions, and the headrest is set to the minimum height position via the minimum height main notch portion. One or more main notch portions are provided below the minimum height main notch portion in the hanging direction of the main headrest stay, and the height position of the headrest can be set to a predetermined height via these main notch portions.

[0012] In addition, in the present invention, the movement limiting mechanism includes a sub-notch portion provided in the sub-headrest stay, which has a minimum height sub-notch portion formed to be at the same height as the minimum height main notch portion, but does not have any sub-notch portion located lower than the minimum height sub-notch portion in the hanging direction of the sub-headrest stay.

[0013] That is, in the present invention, the sub-notch portion has a minimum height sub-notch portion formed to be at the same height as the minimum height main notch portion, so that the headrest can be set to the minimum height position via not only the minimum height main notch portion but also the minimum height sub-notch portion. Furthermore, in the present invention, there is no sub-notch portion located lower than the minimum height sub-notch portion in the hanging direction of the sub-headrest stay, so that downward movement of the sub-headrest stay (headrest) can be restricted (locked state).

[0014] In this way, in the present invention, since the downward movement of the headrest is restricted not only by the main headrest stay but also by the sub-headrest stay at the headrest's lowest height position, it is not necessary to set the headrest's lowest height position by, for example, abutting the lower surface of the headrest against the upper surface of the seat back, and therefore, in the present invention, it is possible to form a gap between the headrest and the seat back at the headrest's lowest height position.

[0015] The headrest height adjustment mechanism described in claim 2 is the headrest height adjustment mechanism described in claim 1, wherein the locking mechanism further includes a main lock portion that is provided on the main support and engages with the main notch portion to restrict the up and down movement of the main headrest stay.

[0016] In the headrest height adjustment mechanism described in claim 2, the locking mechanism further includes a main locking portion. As described above, the main notch portions are provided on the main headrest stay, and multiple main notch portions are formed along the hanging direction of the main headrest stay (height direction of the headrest). Meanwhile, the main locking portion is provided on the main support, and by engaging with the main notch portions provided on the main headrest stay, the up and down movement of the main headrest stay (headrest) is restricted (locked state).

[0017] The headrest height adjustment mechanism described in claim 3 is the headrest height adjustment mechanism described in claim 2, wherein the movement limiting mechanism is provided on the sub-support and further includes a sub-lock portion that engages with the sub-notch portion to limit the upward and downward movement of the sub-headrest stay.

[0018] In the headrest height adjustment mechanism of claim 3, the movement limiting mechanism further includes a sub-lock portion. As described above, the sub-notch portion is provided on the sub-headrest stay and is formed to be at the same height as the minimum height notch portion among the multiple main notches that sets the headrest to the minimum height position. Meanwhile, the sub-lock portion is provided on the sub-support and engages with the sub-notch portion to limit downward movement of the sub-headrest stay (locked state).

[0019] That is, in the present invention, when the headrest is at its lowest height position, the main lock portion on the locking mechanism side engages with the main notch portion to restrict downward movement of the main headrest stay side, and the sub-lock portion on the movement restriction mechanism side engages with the sub-notch portion to restrict downward movement of the sub-headrest stay (headrest) (locked state).

[0020] In this way, at the headrest's lowest height position, downward movement of the headrest is restricted not only by the main headrest stay but also by the sub-headrest stay, so that it is not necessary to set the headrest's lowest height position by, for example, abutting the lower surface of the headrest against the upper surface of the seat back. Therefore, in the present invention, it is possible to form a gap between the headrest and the seat back at the headrest's lowest height position.

[0021] The headrest height adjustment mechanism of claim 4 is the headrest height adjustment mechanism of claim 3, wherein the sub-notch portion is a recess in which the surface of the sub-headrest stay is recessed along a direction perpendicular to the hanging direction of the sub-headrest stay, and into which the sub-lock portion can enter, and the recess is formed on the upper side within the recess and includes a horizontal portion against which the upper surface of the sub-lock portion that has entered the recess abuts in a surface-contacting manner, and an inclined portion that is connected to the horizontal portion and inclined in a direction toward the surface side of the sub-headrest stay as it moves downward within the recess.

[0022] In the headrest height adjustment mechanism described in claim 4, the sub-notch portion is a recess in the surface of the sub-headrest stay along a direction perpendicular to the hanging direction of the sub-headrest stay, and the sub-lock portion can enter into the recess.

[0023] Here, the recess is configured to include a horizontal portion and an inclined portion, and the horizontal portion is formed on the upper side of the recess, and the upper surface of the sub-lock portion that has entered the recess abuts against the horizontal portion so as to be able to make surface contact. When the upper surface of the sub-lock portion abuts against the horizontal portion of the recess so as to be able to make surface contact (contact or surface contact), the downward movement of the sub-headrest stay (headrest) in which the recess is formed is restricted (locked state).

[0024] On the other hand, the inclined portion is connected to the horizontal portion and inclined toward the surface of the sub-headrest stay as it moves downward within the recess. Therefore, the inclined surface acts as a so-called cam surface, and the force attempting to lift the sub-headrest stay can be converted into a force that moves the sub-lock portion outward from within the recess. This releases the locked state of the sub-lock portion.

[0025] That is, in the present invention, when the headrest is at its lowest height position, the sub-lock portion remains locked and the headrest cannot be moved downward, but when the headrest is moved upward, the sub-lock portion is released from its locked state.

[0026] The headrest height adjustment mechanism described in claim 5 is the headrest height adjustment mechanism described in claim 1 or claim 2, wherein the movement limiting mechanism is provided on the sub-headrest stay and includes a collar that abuts against the headrest and the sub-support at the lowest height position of the headrest to limit downward movement of the sub-headrest stay.

[0027] In the headrest height adjustment mechanism described in claim 5, the movement limiting mechanism includes a collar provided on the sub-headrest stay. The collar abuts against the headrest and the sub-support when the headrest is at its lowest height, thereby limiting downward movement of the sub-headrest stay (headrest) (locked state).

[0028] That is, in the present invention, when the headrest is at its lowest height position, the main lock portion on the locking mechanism engages with the main notch portion to restrict the downward movement of the main headrest stay, and the collar abuts against the headrest and the sub-support to restrict the downward movement of the sub-headrest stay.

[0029] The headrest height adjustment mechanism described in claim 6 is the headrest height adjustment mechanism described in claim 1 or claim 2, wherein the movement limiting mechanism is formed on the sub-headrest stay and includes a bent portion that interferes with the sub-support at the lowest height position of the headrest to limit downward movement of the sub-headrest stay.

[0030] In the headrest height adjustment mechanism described in claim 6, the movement limiting mechanism includes a bent portion formed in the sub-headrest stay. The bent portion interferes with the sub-support at the lowest height position of the headrest, thereby limiting downward movement of the sub-headrest stay (headrest) (locked state).

[0031] That is, in the present invention, at the lowest height position of the headrest, the main lock portion on the locking mechanism engages with the main notch portion to restrict the downward movement of the main headrest stay, and the bent portion formed on the sub-headrest stay interferes with the sub-support to restrict the downward movement of the sub-headrest stay.

[0032] The headrest height adjustment mechanism described in claim 7 is the headrest height adjustment mechanism described in claim 1 or claim 2, wherein the movement limiting mechanism is formed on the sub-headrest stay and includes a protrusion that interferes with the sub-support at the lowest height position of the headrest to limit downward movement of the sub-headrest stay.

[0033] In the headrest height adjustment mechanism described in claim 7, the movement limiting mechanism includes a protrusion formed on the sub-headrest stay. The protrusion interferes with the sub-support at the lowest height position of the headrest, thereby limiting downward movement of the sub-headrest stay (headrest) (locked state).

[0034] That is, in the present invention, at the lowest height position of the headrest, the main lock portion on the locking mechanism engages with the main notch portion to restrict downward movement of the main headrest stay, and the protrusion portion formed on the sub-headrest stay interferes with the sub-support to restrict downward movement of the sub-headrest stay. [Effects of the Invention]

[0035] As described above, the headrest height adjustment mechanism described in claim 1 has the excellent effect of making it possible to reduce the size of the headrest while ensuring the required height of the headrest at its minimum height.

[0036] The headrest height adjustment mechanism described in claim 2 has the excellent effect of being able to limit the vertical movement of the main headrest stay with a simple configuration.

[0037] The headrest height adjustment mechanism described in claim 3 has the excellent effect of being able to limit the downward movement of the sub-headrest stay at the lowest height position of the headrest by using not only the main headrest stay but also the sub-notch portion and the sub-lock portion.

[0038] The headrest height adjustment mechanism described in claim 4 has the excellent effect of being able to release the locked state of the sub-headrest stay by moving the headrest upward while the sub-headrest stay is in a locked state in which its downward movement is restricted.

[0039] The headrest height adjustment mechanism described in claim 5 has the excellent effect of being able to limit the downward movement of the sub-headrest stay by using the collar when the headrest is at its lowest height position.

[0040] The headrest height adjustment mechanism described in claim 6 has the excellent effect of being able to limit downward movement of the sub-headrest stay by the bent portion formed in the sub-headrest stay when the headrest is at its lowest height position.

[0041] The headrest height adjustment mechanism described in claim 7 has the excellent effect of being able to limit the downward movement of the sub-headrest stay at the lowest height position of the headrest by the protrusion formed on the sub-headrest stay. [Brief explanation of the drawings]

[0042] [Figure 1] 3 is a cross-sectional view showing the headrest height adjustment mechanism of the present embodiment as viewed from the front side. FIG. [Figure 2] FIG. 2 is an exploded perspective view showing the headrest height adjustment mechanism of the present embodiment. [Figure 3] 2 is an enlarged cross-sectional view showing a main part of the headrest height adjustment mechanism of the present embodiment in FIG. 1. FIG. [Figure 4] FIG. 2 is an exploded perspective view showing the headrest height adjustment mechanism of the present embodiment. [Figure 5] 1A is a cross-sectional view from the front side showing a headrest height adjustment mechanism as a comparative example, and FIG. 1B is a cross-sectional view from the front side showing the headrest height adjustment mechanism of this embodiment. [Figure 6] 10 is a front view illustrating the operation of the headrest height adjustment mechanism of the present embodiment. FIG. [Figure 7] 10 is a cross-sectional view of a first modified example of the headrest height adjustment mechanism of the present embodiment, as viewed from the front side. FIG. [Figure 8] 1A and 1B show a second modified example of the headrest height adjustment mechanism of the present embodiment, in which (A) is a cross-sectional view seen from the front side, and (B) is a cross-sectional view seen from the side. [Figure 9] FIG. 10 is a cross-sectional view showing a third modified example of the headrest height adjustment mechanism of the present embodiment, as viewed from the side. DETAILED DESCRIPTION OF THE INVENTION

[0043] A headrest to which a headrest height adjustment mechanism according to this embodiment is applied will be described below with reference to the drawings. Note that in the following drawings, the arrow FR, as appropriate, indicates the forward direction of the vehicle seat (the direction in which the seated person faces), the arrow UP indicates the upward direction of the vehicle seat, and the arrow RH indicates the rightward direction of the vehicle seat. Hereinafter, when the directions of front / rear, up / down, and left / right are simply used in the description, they refer to the front / rear of the vehicle seat, the up / down of the vehicle seat, and the left / right of the vehicle seat when facing the direction of travel, unless otherwise specified.

[0044] (Configuration of headrest height adjustment mechanism) First, the configuration of the headrest height adjustment mechanism according to this embodiment will be described.

[0045] As shown in FIG. 1, a vehicle seat 10 includes a seat cushion (not shown) on which an occupant sits, a seat back 12 that stands upright from the rear end of the seat cushion and supports the upper body of the occupant seated on the seat cushion, and a headrest 14 that is attached to an upper end 12A of the seat back 12 and supports the head of the occupant seated on the seat cushion.

[0046] The headrest 14 is formed of a foam such as urethane foam and is elastically deformable. The headrest 14 is trapezoidal in front view and substantially triangular in side view, with a pair of headrest stays (legs) 16 hanging down from the left and right sides in the seat width direction from a lower surface 14A of the headrest 14. The headrest stays 16 are tubular and made up of two members. Note that the headrest stay 16 may be made up of a single member formed by connecting the legs at the upper end, as long as it has a pair of left and right legs.

[0047] In the following description, of the headrest stay 16, one side that is arranged on the outer side in the vehicle width direction is referred to as the main headrest stay 18, and the other side that is arranged on the inner side in the vehicle width direction is referred to as the sub-headrest stay 20. Note that the side that is on the inner side in the vehicle width direction may be referred to as the main headrest stay 18, and the side that is on the outer side in the vehicle width direction may be referred to as the sub-headrest stay 20.

[0048] The main headrest stay 18 and the sub-headrest stay 20 are held by the seat back 12. The seat back 12, like the headrest 14, is made of a foam such as urethane foam and is elastically deformable.

[0049] Furthermore, insertion holes 22 and 24 are respectively formed in the upper part of the seat back 12 along the vertical direction of the vehicle. The insertion holes 22 and 24 are rectangular in plan view, and a square tubular main support 26 serving as a support member for supporting the main headrest stay 18 is inserted into the insertion hole 22, and a square tubular sub-support 28 serving as a support member for supporting the sub-headrest stay 20 is inserted into the insertion hole 24.

[0050] Then, with the main support 26 inserted into the insertion hole 22, the main headrest stay 18 is inserted into the main support 26, and with the sub-support 28 inserted into the insertion hole 24, the sub-headrest stay 20 is inserted into the sub-support 28.

[0051] In this embodiment, as the height adjustment mechanism 29 of the headrest 14, a lock mechanism 30 is provided on the main support 26 side, and a movement limiting mechanism 32 is provided on the sub-support 28 side.

[0052] For convenience of explanation, the movement limiting mechanism 32 will be described first, followed by the locking mechanism 30.

[0053] (Movement restriction mechanism) As described above, the movement limiting mechanism 32 is provided on the sub-support 28 side.

[0054] 4, the sub-support 28 is formed at its upper end with a flange portion 34 that protrudes outward from the sub-support 28. The flange portion 34 is formed with its longitudinal direction aligned with the seat width direction (direction of arrow A). The center of the flange portion 34 is formed as a round hole 36 that communicates with the interior of the square cylindrical sub-support 28, and is formed to correspond to the shape of the cylindrical sub-headrest stay 20.

[0055] 2, the sub-support 28 has a pair of side wall portions 28A provided along a direction perpendicular to the sheet width direction (the direction of arrow A), and claw portions 38 are provided at approximately the center in the height direction of the sub-support 28. An inverted U-shaped through hole 40 that opens downward is formed around the claw portion 38, and this through hole 40 allows the claw portion 38 to elastically deform toward the inside of the sub-support 28.

[0056] 1, a locking hole (not shown) recessed in the horizontal direction is provided inside the insertion hole 24 into which the sub-support 28 is inserted. When the sub-support 28 is inserted into the insertion hole 24, the claw portions 38 elastically deform toward the inside of the sub-support 28, allowing the sub-support 28 to move toward the back of the insertion hole 24. When the flange portions 34 of the sub-support 28 abut against the upper surface 12B of the seat back 12 and the claw portions 38 of the sub-support 28 reach a position facing the locking hole, the claw portions 38 return to their original position and are locked by the wall of the locking hole.

[0057] As a result, the sub-support 28 is prevented from coming off the insertion hole 24 formed in the upper part of the seat back 12 and is attached within the insertion hole 24.

[0058] As described above, the seat back 12 is elastically deformable, so the position of the upper surface 12B of the seat back 12 varies depending on the pressing force. The insertion hole 24 has a rectangular shape in a plan view, and the sub-support 28 has a square cylindrical shape. In other words, the sub-support 28 is set so as not to rotate relative to the insertion hole 24.

[0059] 4, a rectangular step 42 having a longitudinal direction that coincides with the seat width direction is recessed in the flange 34 of the sub-support 28. A rectangular frame-shaped sub-lock plate (sub-lock portion) 44 having a longitudinal direction that coincides with the seat width direction is housed within this step 42, and a rectangular hole 46 is formed in the center of the sub-lock plate 44.

[0060] The longitudinal dimension of the sub-lock plate 44 is set to be shorter than the longitudinal dimension of the step portion 42, and the sub-lock plate 44 is capable of moving within the step portion 42 along its longitudinal direction.

[0061] A rectangular parallelepiped rib 48 is formed on the underside of the sub-lock plate 44, on the rectangular hole 46 side, along the width direction perpendicular to the longitudinal direction of the sub-lock plate 44. The rib 48 reduces the contact area between the sub-lock plate 44 and the step portion 42, thereby reducing friction when the sub-lock plate 44 moves within the step portion 42.

[0062] A cylindrical protrusion 50 protrudes from the outer longitudinal side surface 44A of the sub-lock plate 44. One end of a coil spring 52 is attached to this protrusion 50. The other end of the coil spring 52 abuts against the inner wall 42A of the step portion 42 that faces the protrusion 50, and the coil spring 52 urges the sub-lock plate 44 toward the inner wall 42B of the step portion 42 that faces the inner wall 42A.

[0063] Furthermore, the sub-lock plate 44 is set so as to overlap a part of the round hole 36 formed in the flange portion 34 of the sub-support 28 while in contact with the inner wall 42B of the step portion 42. The flange portion 34 of the sub-support 28 is provided with an upper support 54 that covers the flange portion 34.

[0064] The upper support 54 has approximately the same outer diameter as the flange 34, and is formed with a step 56 and a round hole 58, similar to the flange 34. The upper part of the sub-lock plate 44 is housed in the step 56. With the sub-lock plate 44 and the coil spring 52 housed in the step 56, the upper support 54 is joined to the flange 34 of the sub-support 28 by welding or the like.

[0065] 1 and 3, the sub-headrest stay 20 is formed with one sub-notch portion (a sub-notch portion for minimum height, which will be described later) 60 as a recess that is recessed along the radial direction of the sub-headrest stay 20 (a direction perpendicular to the hanging direction of the sub-headrest stay 20). The sub-notch portion 60 is provided on the side of the sub-lock plate 44 where the coil spring 52 is provided, and the sub-lock plate 44 can enter (engage) into the sub-notch portion 60.

[0066] As shown in Figures 3 and 4, the sub-headrest stay 20 is inserted into the sub-support 28 and then into the round hole 58 of the support upper 54, the rectangular hole 46 of the sub-lock plate 44, and the round hole 36 of the flange portion 34.

[0067] In this state, as described above, the sub-lock plate 44 is biased by the coil spring 52 toward the inner wall 42B of the stepped portion 42. When the sub-lock plate 44 abuts against the inner wall 42B of the stepped portion 42, the sub-lock plate 44 overlaps with the circular hole 36. In other words, the sub-lock plate 44 protrudes toward the circular hole 36.

[0068] Therefore, when the sub-headrest stay 20 is inserted into the sub-support 28, the coil spring 52 is biased by the sub-headrest stay 20, and the biasing force of the coil spring 52 causes the inner wall 44C on the side of the sub-lock plate 44 where the coil spring 52 is provided to abut against the surface 20A of the sub-headrest stay 20.

[0069] As described above, the sub-notch portion 60 is recessed along the radial direction of the sub-headrest stay 20 and includes a horizontal portion 60A and an inclined portion 60B. Therefore, when the sub-notch portion 60 of the sub-headrest stay 20 faces the sub-lock plate 44, the sub-lock plate 44 enters the sub-notch portion 60 due to the biasing force of the coil spring 52. In this way, the sub-lock plate 44 is biased toward the sub-notch portion 60 by the coil spring 52, and therefore the state in which the sub-lock plate 44 enters the sub-notch portion 60 is maintained.

[0070] Here, the horizontal portion 60A is formed on the upper side within the sub-notch portion 60, and the upper surface 44B of the sub-lock plate 44 that has entered the sub-notch portion 60 abuts against it in a surface-contacting manner. In other words, when the sub-lock plate 44 enters the sub-notch portion 60 and the upper surface 44B of the sub-lock plate 44 is in contact or surface-contact with the horizontal portion 60A of the sub-notch portion 60, the downward movement of the sub-headrest stay 20 (headrest 14) is restricted, and a so-called locked state is established.

[0071] On the other hand, the inclined portion 60B is connected to the horizontal portion 60A, and is inclined in a direction toward the surface 20A of the sub headrest stay 20 as it moves downward within the sub notch portion 60. Therefore, the force attempting to lift the sub headrest stay 20 can be converted into a force that moves the sub lock plate 44 outward from within the sub notch portion 60. This releases the locked state of the sub lock plate 44.

[0072] At this time, the coil spring 52 is biased in a direction resisting the biasing force, so when the surface 20A of the sub-headrest stay 20 reaches a position facing the inner wall 44C of the sub-lock plate 44, the biasing force of the coil spring 52 causes the inner wall 44C of the sub-lock plate 44 to abut against the surface 20A of the sub-headrest stay 20.

[0073] (locking mechanism) Next, a description will be given of the locking mechanism 30. Note that in the locking mechanism 30, components that are substantially the same as those in the movement limiting mechanism 32 will be given the same component names as those in the movement limiting mechanism 32, and duplicated descriptions will be omitted.

[0074] As described above, the locking mechanism 30 is provided on the main support 26 side. As shown in FIGS. 1 and 3, a flange portion 62 is formed on the upper end of the main support 26. Furthermore, a pair of opposing side wall portions 26A of the main support 26 are provided with claw portions 66, respectively, which are engaged with the wall of a locking hole (not shown) formed in the insertion hole 22. As a result, the main support 26, like the sub-support 28, is prevented from slipping out of the insertion hole 22 formed in the upper part of the seat back 12 and is attached to the insertion hole 22.

[0075] Meanwhile, a stepped portion 68 is recessed in the flange portion 62 of the main support 26, similar to the sub-support 28, and a main lock plate (main lock portion) 70 having a substantially rectangular frame shape is housed within the stepped portion 68. This main lock plate 70 is movable within the stepped portion 68 along its longitudinal direction.

[0076] In addition, the main lock plate 70 is biased in a direction away from the inner wall 68A within the step portion 68 that faces the outer longitudinal side surface 70A of the main lock plate 70 by a coil spring 72 attached to the outer longitudinal side surface 70A of the main lock plate 70.

[0077] Here, similar to the sub-support 28, the flange portion 62 of the main support 26 is provided with a support upper 74 that covers the flange portion 62, and the support upper 74 and the flange portion 62 house the main lock plate 70 and coil spring 72.

[0078] An opening 74A is formed in the upper support 74. An unlocking knob 76 is provided on the main lock plate 70 on the side opposite to the side surface 70A, and the unlocking knob 76 is configured to be exposed to the vehicle interior 78 through the opening 74A. By moving the unlocking knob 76 in the horizontal direction, the main lock plate 70 moves within the step portion 68.

[0079] Meanwhile, the main headrest stay 18 is formed with a plurality of (here, three) main notch portions 80 that are recessed along the radial direction of the main headrest stay 18 along the hanging direction (along the height direction of the headrest 14). The main lock plate 70 can enter into the main notch portions 80.

[0080] Here, three main notch portions 80 (notch portions 80A, 80B, 80C) are provided. When the main lock plate 70 is inserted into the notch portion 80A provided on the headrest 14 side of the main headrest stay 18, the headrest 14 is at its lowest height, and therefore, this notch portion 80A is referred to as the main notch portion for minimum height. Hereinafter, the "notch portion 80A" will be referred to as the "main notch portion for minimum height 80A."

[0081] Furthermore, the notch portion 80C provided in the main headrest stay 18 at the position farthest from the headrest 14 (the tip side) is the main notch portion 80C for maximum height because the headrest 14 reaches its maximum height when the main lock plate 70 is inserted into the notch portion 80C. Hereinafter, the "notch portion 80C" will be referred to as the "main notch portion 80C for maximum height."

[0082] The notch portion 80B provided between the minimum height main notch portion 80A and the maximum height main notch portion 80C is referred to as the intermediate height main notch portion 80B. When the main lock plate 70 is inserted into the intermediate height main notch portion 80B, the headrest 14 is at a height intermediate between the maximum height position of the headrest 14, where the headrest 14 is at its highest, and the minimum height position of the headrest 14, where the headrest 14 is at its lowest (the intermediate height position of the headrest 14).

[0083] The evaluation of whiplash injury reduction performance conducted in the European New Car Assessment Program (E-NCAP) specifies the intermediate and minimum height positions of the headrest 14. Therefore, it is necessary to ensure the height of the headrest 14 required at the intermediate and minimum height positions P of the headrest 14.

[0084] The main notch portion 80 is formed as a recess along the radial direction of the main headrest stay 18, and similar to the sub-notch portion 60 formed in the sub-headrest stay 20, when the main notch portion 80 faces the main lock plate 70, the main lock plate 70 enters into the main notch portion 80 due to the biasing force of the coil spring 72.

[0085] In this way, main lock plate 70 is biased toward main notch portion 80 by coil spring 72, so main lock plate 70 remains inserted into minimum height main notch portion 80A, intermediate height main notch portion 80B, and maximum height main notch portion 80C. This makes the height of headrest 14 adjustable, and headrest 14 is maintained at the adjusted height.

[0086] Here, the minimum height main notch portion 80A and the intermediate height main notch portion 80B have substantially the same shape as the sub-notch portion 60 formed in the sub-headrest stay 20. That is, although not shown, they are configured to include a horizontal portion and an inclined portion. Therefore, when the main headrest stay 18 (headrest 14) is moved upward with the main lock plate 70 inserted into the minimum height main notch portion 80A and the intermediate height main notch portion 80B, the locked state by the main lock plate 70 is released.

[0087] On the other hand, the maximum height main notch portion 80C does not have an inclined portion. In other words, it has two horizontal portions facing each other above and below. Therefore, when the main lock plate 70 is inserted into the maximum height main notch portion 80C, the locked state by the main lock plate 70 cannot be released even if an attempt is made to move the main headrest stay 18 upward.

[0088] Therefore, when the main lock plate 70 has entered the main notch portion 80C for maximum height, that is, when the headrest 14 is at the maximum height position, the main lock plate 70 is moved using the unlock knob 76 to release the locked state of the main lock plate 70.

[0089] (Action and effect of headrest height adjustment mechanism) Next, the operation and effect of the headrest height adjustment mechanism according to this embodiment will be described.

[0090] 1 to 3, in this embodiment, the height adjustment mechanism 29 of the headrest 14 is configured to include a main support 26 and a sub-support 28. The main support 26 is provided on the main headrest stay 18 side and is equipped with a locking mechanism 30 that can adjust the height of the headrest 14 and lock the headrest 14 at a predetermined height. On the other hand, the sub-support 28 is provided on the sub-headrest stay 20 side and is equipped with a movement limiting mechanism 32 that limits the downward movement of the headrest 14.

[0091] More specifically, in this embodiment, the locking mechanism 30 includes a main notch portion 80 and a main lock plate 70. The main notch portion 80 is provided on the main headrest stay 18, and multiple main notch portions 80 are formed along the height direction of the headrest 14.

[0092] Furthermore, the main lock plate 70 is provided on the main support 26, and the vertical movement of the main headrest stay 18 (headrest 14) is restricted (locked state) by the main lock plate 70 engaging with the main notch portion 80 provided on the main headrest stay 18. In other words, in this embodiment, the vertical movement of the main headrest stay 18 can be restricted with a simple configuration.

[0093] Here, the main notch portion 80 is formed in the main headrest stay 18 and the main lock plate 70 is engaged therewith, thereby restricting the movement of the main headrest stay 18 at a predetermined position with a simple configuration, but the present invention is not limited to this as long as it is possible to restrict the movement of the main headrest stay 18 at a predetermined position.

[0094] On the other hand, the movement limiting mechanism 32 is configured to include a sub-notch portion 60 and a sub-lock plate 44. The sub-notch portion 60 is provided on the sub-headrest stay 20, and is formed to be at the same height as the minimum height main notch portion 80A, which is provided on the headrest 14 side of the multiple main notch portions 80.

[0095] The sub-lock plate 44 is provided on the sub-support 28 and engages with the sub-notch portion 60 to restrict downward movement of the sub-headrest stay 20 (headrest 14) (locked state).

[0096] That is, in this embodiment, at the lowest height position P of the headrest 14, the main lock plate 70 on the locking mechanism 30 side engages with the main notch portion 80 to restrict downward movement of the main headrest stay 18 side, and the sub lock plate 44 on the movement restricting mechanism 32 side engages with the sub notch portion 60 to restrict downward movement of the sub headrest stay 20 side (locked state).

[0097] In this way, at the lowest height position P of the headrest 14, the downward movement of the headrest 14 is restricted not only by the main headrest stay 18 but also by the sub-headrest stay 20. Therefore, in this embodiment, the downward movement of the headrest 14 can be suppressed more effectively than when the downward movement of the headrest 14 is restricted only by the main headrest stay 18.

[0098] As a result, in this embodiment, for example, as shown in Fig. 5(A) as a comparative example, it is not necessary to set the lowest height position P' of the headrest 100 by abutting the lower surface 100A of the headrest 100 against the upper surface 102A of the seat back 102. As a result, in this embodiment, it is possible to form a gap H between the headrest 14 and the seat back 12 as shown in Fig. 5(B).

[0099] As described above, the movement limiting mechanism 32 limits the downward movement of the headrest 14 (in a so-called locked state) with a gap H provided between the headrest 14 and the seat back 12 at the minimum height position P where the headrest 14 is at its lowest height when the main headrest stay 18 is engaged with the main support 26, thereby maintaining the headrest 14 at its minimum height position.

[0100] 5A, as a comparative example, when the lowest height position P of the headrest 14 is the same, the size of the headrest 14 can be reduced in the height direction by the amount of the gap H. In other words, in this embodiment, the headrest 14 can be made smaller in size while the height of the headrest 14 required at the lowest height position P of the headrest 14 is ensured.

[0101] The European New Car Assessment Program (E-NCAP) specifies the intermediate and minimum height positions of headrests. The intermediate height position of the headrest is set within ±10 mm of the midpoint between the minimum and maximum height positions of the headrest.

[0102] As described above, the headrest 14 is capable of elastic deformation, and therefore, variations in dimensions occur due to elastic deformation of the headrest 14. For this reason, if the position where the lower surface 100A of the headrest 100 abuts against the upper surface 102A of the seat back 102 is set to the lowest height position P' of the headrest 100, as in the comparative example shown in Fig. 5(A), it becomes necessary to take into account the dimensions of the headrest 100 that are subject to elastic deformation.

[0103] As a result, as shown in FIG. 6, the minimum height position P' of the headrest 100 is set above the minimum height notch portion 104, taking into account the dimension X of the elastic deformation of the headrest 100, and an intermediate height position Q' of the headrest 100 is set between this and the maximum height position R' of the headrest 100.

[0104] On the other hand, in this embodiment, because a gap H is provided between the headrest 14 and the seat back 12, it is not necessary to consider dimensional variations due to elastic deformation of the headrest 14 itself. Therefore, the minimum height position P of the headrest 14 is set to the position of the minimum height main notch portion 80A, and an intermediate height position Q of the headrest 14 is set between the minimum height main notch portion 80A and the maximum height main notch portion 80C.

[0105] That is, in this embodiment, the height of the headrest 14 at the intermediate height position Q is higher than in the comparative example. Therefore, in this embodiment, the height of the headrest 14 is higher than in the comparative example, so that the upper part of the headrest 14 can be cut off by that amount, and as a result, the headrest 14 can be made smaller.

[0106] Furthermore, by making the headrest 14 smaller in this manner, in this embodiment, the feeling of oppression in the vehicle interior 78 caused by a large headrest 14 is reduced, and the forward field of view for rear seat passengers can be expanded compared to when the headrest 14 is large.

[0107] In addition, in this embodiment, as shown in Figures 1 to 3, the sub-notch portion 60 is a recess in which the surface 20A of the sub-headrest stay 20 is recessed along a direction perpendicular to the hanging direction of the sub-headrest stay 20, and the sub-lock plate 44 can enter into the sub-notch portion 60.

[0108] The sub-notch portion 60 is configured to include a horizontal portion 60A and an inclined portion 60B, and the horizontal portion 60A is formed on the upper side within the sub-notch portion 60, and the upper surface 44B of the sub-lock plate 44 that has entered the sub-notch portion 60 abuts against it in a surface-contacting manner. When the upper surface 44B of the sub-lock plate 44 is in contact or surface-contact with the horizontal portion 60A of the sub-notch portion 60, the downward movement of the sub-headrest stay 20 in which the sub-notch portion 60 is formed is restricted (locked state).

[0109] On the other hand, the inclined portion 60B is connected to the horizontal portion 60A, and is inclined in a direction toward the surface 20A of the sub headrest stay 20 as it moves downward within the sub notch portion 60. Therefore, the inclined portion 60B acts as a so-called cam surface, and the force attempting to lift the sub headrest stay 20 can be converted into a force that moves the sub lock plate 44 outward from within the sub notch portion 60. This releases the locked state of the sub lock plate 44.

[0110] That is, in this embodiment, when the headrest 14 is at its lowest height position P, the sub-lock plate 44 remains locked and the headrest 14 cannot be moved downward, but when the headrest 14 is moved upward, the sub-lock plate 44 is released from its locked state.

[0111] (Modification of this embodiment) In the above embodiment, as shown in Figure 1, the movement limiting mechanism 32 is configured such that a sub-notch portion 60 is formed on the surface 20A of the sub-headrest stay 20, and the sub-lock plate 44 enters (engages) the sub-notch portion 60, thereby limiting the downward movement of the sub-headrest stay 20.

[0112] However, this is not limited to this, as long as the downward movement of the headrest 14 is restricted not only on the main headrest stay 18 side but also on the sub-headrest stay 20 side when a gap H is provided between the headrest 14 and the seat back 12 at the lowest height position P of the headrest 14.

[0113] For example, as a first modification, as shown in Fig. 7, the movement limiting mechanism 82 is configured to include a collar 84 provided on the sub-headrest stay 20. The collar 84 is shaped like a truncated cone with a smaller diameter on the lower surface side, and the sub-headrest stay 20 is inserted through the collar 84. Then, at the lowest height position P of the headrest 14, the collar 84 may come into contact with the headrest 14 and the support upper 54 of the sub-support 28, thereby limiting the downward movement of the sub-headrest stay 20 (headrest 14).

[0114] 8(A) and 8(B), as a second modification, a movement limiting mechanism 86 is configured to include a bent portion 90 formed in a sub-headrest stay 88. This bent portion 90 may interfere with the support upper 54 of the sub-support 28 at the lowest height position P of the headrest 14, thereby limiting the downward movement of the sub-headrest stay 88 (headrest 14).

[0115] 9, as a third modification, a movement limiting mechanism 92 is configured to include a protrusion 96 formed on a sub-headrest stay 94. This protrusion 96 may interfere with the sub-support 28 at the lowest height position P of the headrest 14, thereby limiting the downward movement of the sub-headrest stay 94 (headrest 14).

[0116] The protrusion 96 may be formed by deforming the shape of the sub-headrest stay 94 itself, or may be formed by attaching a separate member to the sub-headrest stay 94, for example.

[0117] Furthermore, although not shown, a rear wall may be provided on the sub-support so that the tip of the sub-headrest stay abuts against the rear wall at the lowest height position P of the headrest 14, thereby restricting the downward movement of the sub-headrest stay.

[0118] The above describes one embodiment of the present invention, but the present invention is not limited to the above, and it goes without saying that it can be implemented in various other modified forms within the scope of the gist of the present invention. [Explanation of symbols]

[0119] 10 Vehicle seats 12 Seat back 14 Headrest 16 Headrest stay (pair of legs) 18 Main headrest stay (one leg) 20 Sub-headrest stay (other leg) 20A Surface (Sub-headrest stay surface) 26 Main Support 28 Sub-support 29 Height adjustment mechanism 30 Locking mechanism 32 Movement restriction mechanism 44 Sub-lock plate (sub-lock part, movement limiting mechanism) 44B top surface (top surface of sub-lock part) 60 Sub-notch part (minimum height sub-notch part, recess, movement limiting mechanism) 60A horizontal section (recess, sub-notch section) 60B Inclined section (recess, sub-notch section) 70 Main lock plate (main lock part, lock mechanism) 80 Main notch (locking mechanism) 80A Minimum height main notch (main notch) 80B Medium height main notch (main notch) 80C Maximum height main notch (main notch) 82 Movement restriction mechanism 84 Collar (movement limiting mechanism) 86 Movement restriction mechanism 88 Sub-headrest stay 90 Bending section (movement limiting mechanism) 92 Movement restriction mechanism 94 Sub-headrest stay 96 Protrusion (movement limiting mechanism) H gap P Minimum height position (minimum headrest height position)

Claims

1. a main support provided on one of a pair of legs hanging down from the left and right sides in the seat width direction of a headrest provided on the upper side of a seat back and held by the seat back, the main support being provided on a main headrest stay side, the main support including a locking mechanism that adjusts the height of the headrest together with the main headrest stay and can lock the headrest at a predetermined height; a sub-support provided on a sub-headrest stay, which is the other leg of the pair of legs, and including a movement limiting mechanism that limits downward movement of the headrest together with the sub-headrest stay in a state where a gap is provided between the headrest and the seat back at a minimum height position where the headrest is at its lowest when the main headrest stay is engaged with the main support, thereby maintaining the minimum height position of the headrest; The invention comprises: the locking mechanism is provided on the main headrest stay and includes a plurality of main notch portions formed along a hanging direction of the main headrest stay, the plurality of main notch portions include a minimum height main notch portion that sets the headrest at the minimum height position, and one or more main notch portions that are positioned lower than the minimum height main notch portion in a hanging direction of the main headrest stay, the movement limiting mechanism includes a sub-notch portion provided in the sub-headrest stay, A headrest height adjustment mechanism in which the sub-notch portion has a minimum height sub-notch portion formed to be at the same height as the minimum height main notch portion, and does not have a sub-notch portion located lower than the minimum height sub-notch portion in the hanging direction of the sub-headrest stay.

2. 2. The headrest height adjustment mechanism according to claim 1, wherein the locking mechanism further includes a main lock portion provided on the main support and engaging with the main notch portion to restrict the vertical movement of the main headrest stay.

3. The headrest height adjustment mechanism according to claim 2, wherein the movement limiting mechanism is provided on the sub-support and further includes a sub-lock portion that engages with the sub-notch portion to limit downward movement of the sub-headrest stay.

4. the sub-notch portion is a recess formed in a surface of the sub-headrest stay along a direction perpendicular to the hanging direction of the sub-headrest stay, and into which the sub-lock portion can enter, The recessed portion is a horizontal portion formed on an upper side of the recessed portion, against which an upper surface of the sub-lock portion that has entered the recessed portion abuts in a surface-contact manner; an inclined portion that is connected to the horizontal portion and inclined toward a surface side of the sub-headrest stay as it extends downward within the recess; The headrest height adjustment mechanism according to claim 3, further comprising:

5. The movement limiting mechanism is 3. The headrest height adjustment mechanism of claim 1, further comprising a collar provided on the sub-headrest stay, which contacts the headrest and the sub-support at the lowest height position of the headrest to limit downward movement of the sub-headrest stay.

6. The movement limiting mechanism is 3. A headrest height adjustment mechanism as described in claim 1 or claim 2, which is configured to include a bent portion formed in the sub-headrest stay, which interferes with the sub-support at the lowest height position of the headrest, thereby limiting downward movement of the sub-headrest stay.

7. The movement limiting mechanism is 3. A headrest height adjustment mechanism as described in claim 1 or claim 2, which is configured to include a protrusion formed on the sub-headrest stay that interferes with the sub-support at the lowest height position of the headrest to limit downward movement of the sub-headrest stay.

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