CN220988195U

CN220988195U - Headrest adjusting structure and seat unit

Info

Publication number: CN220988195U
Application number: CN202322462290.9U
Authority: CN
Inventors: 蔡赛军; 李晓鸿; 王海波
Original assignee: Ruimai Technology Co ltd
Current assignee: Ruimai Technology Co ltd
Priority date: 2023-09-11
Filing date: 2023-09-11
Publication date: 2024-05-24
Anticipated expiration: 2033-09-11

Abstract

The utility model provides a headrest adjusting structure and a seat unit, wherein one end of a first driving plate of the headrest adjusting structure is pivotally connected to a base plate, the other end of the first driving plate is pivotally connected to a first extension plate, and the first extension plate is pivotally connected to a mounting plate; one end of the second driving plate is pivotally connected to the base plate, the other end of the second driving plate is pivotally connected to the second extending plate, and the second extending plate is pivotally connected to the mounting plate; the first driving plate is pivotally connected with the second extending plate, and the connecting point of the first driving plate and the second extending plate is a first pivot point and is positioned between two end parts of the first driving plate; the driving piece drives the headrest adjusting structure to switch between a storage state and an extension state; the mounting plate is provided with a fitting plane, and when the headrest adjusting structure is switched between the housed state and the extended state, the turning angle of the fitting plane is α, α=110° -150 °. The utility model has simple structure and can realize wide-range angle adjustment of the headrest.

Description

Headrest adjusting structure and seat unit

Technical Field

The utility model relates to the technical field of seat accessories, in particular to a headrest adjusting structure and a seat unit.

Background

Functional sofas or functional seats are popular in that they enable posture adjustment. Functional sofas commonly found on the market generally comprise a seat and a backrest, on which a headrest is usually mounted, the angle of which is usually adjustable in order to improve the comfort of the user. In the prior art, the automatic adjustment is realized by a traditional manual adjustment mode or a mechanical structure. However, the traditional manual adjustment has large workload and is not beneficial to user experience; in the existing mechanical structure adjusting mode, the corresponding mechanical structure is complex, and the headrest is adjusted, particularly the angle adjusting range of the headrest is small, so that the user requirement cannot be met.

Disclosure of utility model

In view of the shortcomings of the prior art, a first object of the present utility model is to provide a headrest adjusting structure, which is simple in construction and capable of achieving adjustment of a wide angle range of a headrest.

A second object of the present utility model is to provide a seating unit that facilitates stowing and transport.

The embodiment of the utility model is realized by the following technical scheme:

A headrest adjusting structure, includes base plate, first drive plate, second drive plate, first extension board, second extension board, mounting panel and driving piece, wherein: one end of the first driving plate is pivotally connected to the base plate, the other end of the first driving plate is pivotally connected to the first extension plate, and the first extension plate is pivotally connected to the mounting plate; one end of the second driving plate is pivotally connected to the base plate, the other end of the second driving plate is pivotally connected to the second extension plate, and the second extension plate is pivotally connected to the mounting plate; the first driving plate is pivotally connected with the second extending plate, and the connection point of the first driving plate and the second extending plate is a first pivot point and is positioned between two end parts of the first driving plate; the driving piece acts on any one of the first driving plate, the second driving plate, the first extending plate, the second extending plate and the mounting plate, so that the headrest adjusting structure is switched between a storage state and an extension state; the mounting plate is provided with a fitting plane, and when the headrest adjusting structure is switched between the storage state and the extended state, the fitting plane has a flip angle of α, α=110° -150 °.

According to a preferred embodiment, said α=120° -134 °.

According to a preferred embodiment, the first extension plate is located outside the second extension plate, the shortest rod section of the second extension plate located between the mounting plate and the first driving plate is defined as a working section, the outer edge of the working section, which is close to one side of the first extension plate, is a working edge, and when the headrest adjusting structure is switched between the storage state and the extension state, and is seen from the outside of the first extension plate towards the direction of the second extension plate, the first extension plate can shield the working edge.

According to a preferred embodiment, the first driving plate is provided with a limiting piece, and the limiting piece is located between the first pivot point and the base plate; when the headrest adjusting structure is in the storage state and the stretching state, the outer edge of one side of the second extending plate, which is away from the first extending plate, is abutted to the limiting piece.

According to a preferred embodiment, the connection point of the first driving plate and the base plate is a second pivot point, and the connection point of the first driving plate and the first extending plate is a third pivot point; the first rotating shaft where the first pivot point is located, the second rotating shaft where the second pivot point is located and the third rotating shaft where the third pivot point is located are parallel to each other, the distance between orthographic projections of the first pivot point and the second pivot point in the first rotating shaft is D1, the distance between orthographic projections of the first pivot point and the third pivot point in the first rotating shaft is D2, and d1:d2=2-2.6.

According to a preferred embodiment, the limiting member is a limiting shaft, and an axial direction of the limiting shaft is parallel to an axial direction of the first rotating shaft; the shortest distance between the second pivot point and the limiting shaft is D3, and the shortest distance between the third pivot point and the limiting shaft is D4, wherein D3 is D4=1-1.5.

According to a preferred embodiment, the d3:d4=1.2-1.4.

According to a preferred embodiment, the mounting plate comprises a mounting portion and a fixing portion connected to each other, the first extension plate and the second extension plate being both connected to the fixing portion; when the headrest adjusting structure is in the storage state, the base plate is on the back side of the mounting portion; when the headrest adjusting structure is in the extended state, the base plate is on the face side of the mounting portion.

According to a preferred embodiment, the fitting plane is provided on the face side of the mounting part; defining a connection point between the first driving plate and the base plate as a second pivot point, wherein the connection point between the second driving plate and the base plate is a fourth pivot point, a second rotating shaft where the second pivot point is positioned is parallel to a fourth rotating shaft where the fourth pivot point is positioned, and an included angle between a connecting line between the second pivot point and the orthographic projection of the fourth pivot point in the axial direction of the second rotating shaft and the assembly plane is beta; when the headrest adjusting structure is in the stowed state, β=80° -100 °; when the headrest adjustment structure is in the extended state, β=30° -50 °.

According to a preferred embodiment, when the headrest adjusting structure is in the stowed state, the β=85° -95 °; when the headrest adjustment structure is in the extended state, the β=35° -45 °.

According to a preferred embodiment, the distance between the second axis of rotation and the fourth axis of rotation is D5, d5=65 mm-75mm.

According to a preferred embodiment, said d5=70 mm-73mm.

According to a preferred embodiment, the minimum height difference of the fitting plane is H, which h=70 mm-120mm, when the headrest adjusting structure is switched between the stowed and extended states.

The seat unit comprises a headrest side plate and the headrest adjusting structure, wherein the base plate is arranged on the inner side of the headrest side plate.

The technical scheme of the embodiment of the utility model has at least the following advantages and beneficial effects:

the headrest adjusting structure provided by the utility model is simple in structure, and can realize the adjustment of the headrest in a large angle range, thereby meeting the requirements of users.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present utility model and therefore should not be considered as limiting the scope, and other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic front view of a headrest adjusting structure according to the present utility model in a stowed condition;

FIG. 2 is a schematic elevational view of the headrest adjusting structure of the present utility model in an extended state;

FIG. 3 is a schematic view of a comparative structure of the headrest structure of the present utility model in a stowed condition and an extended condition;

FIG. 4 is a schematic perspective view of the present utility model after the two headrest adjusting structures are linked;

FIG. 5 is a first perspective view of the two headrest adjustment structures of the present utility model assembled to a headrest side plate;

Fig. 6 is a second perspective view of the present utility model after two headrest adjusting structures are assembled to a headrest side plate.

Icon: 11. a substrate; 12. a first driving plate; 121. a limiting piece; 13. a second driving plate; 14. a first extension plate; 15. a second extension plate; 151. a working edge; 16. a mounting plate; 161. a mounting part; 1611. an assembly plane; 162. a fixing part; 21. a first cross beam; 22. a second cross beam; 221. an adapter plate; 3. a driving member; 4. a headrest side plate; 5. headrest support plate; a. a first pivot point; b. a second pivot point; c. a third pivot point; d. and a fourth pivot point.

Detailed Description

For a better understanding and implementation, the technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the drawings in the embodiments of the present utility model.

In the description of the present utility model, it should be noted that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, merely to facilitate description of the present utility model and simplify the description, and do not indicate or imply that the apparatus or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present utility model.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this utility model belongs. The terminology used herein in the description of the utility model is for the purpose of describing particular embodiments only and is not intended to be limiting of the utility model.

Referring to fig. 1 to 6, a headrest adjusting structure is applied to a seat unit (not shown), and is particularly used for adjusting a headrest angle of the seat unit. The seat unit includes at least a seat portion and a backrest, the headrest adjusting structure being fitted to the backrest, the headrest being at an end of the backrest remote from the seat portion.

In use, optionally, as shown in fig. 4, the two headrest adjusting structures are arranged in mirror image and are linked through the first beam 21 and the second beam 22, so that the adjustment of the two headrest adjusting structures is realized through one driving piece 3, and the structural stability of the seat unit using the headrest adjusting structures is improved. It will be appreciated that in some use scenarios, angular adjustment of the headrest of the seating unit may be accomplished using a single headrest adjustment structure as well.

For convenience of description, a single headrest adjusting structure, specifically, a headrest adjusting structure on the left side in fig. 4 is described as an example.

As shown in fig. 1 to 3, the headrest adjusting structure includes a base plate 11, a first drive plate 12, a second drive plate 13, a first extension plate 14, a second extension plate 15, a mounting plate 16, and a driver 3, wherein: one end of the first drive plate 12 is pivotally connected to the base plate 11, the other end of the first drive plate 12 is pivotally connected to the first extension plate 14, and the first extension plate 14 is pivotally connected to the mounting plate 16; one end of the second driving plate 13 is pivotally connected to the base plate 11, the other end of the second driving plate 13 is pivotally connected to the second extension plate 15, and the second extension plate 15 is pivotally connected to the mounting plate 16; the first driving plate 12 is pivotally connected with the second extending plate 15, and the connection point of the first driving plate 12 and the second extending plate is a first pivot point a and is positioned between two end parts of the first driving plate 12; the driving piece 3 acts on any one of the first driving plate 12, the second driving plate 13, the first extension plate 14, the second extension plate 15, and the mounting plate 16 to switch the headrest adjusting structure between the housed state and the extended state; the mounting plate 16 is provided with a fitting plane 1611, and when the headrest adjusting structure is switched between the housed state and the extended state, the fitting plane 1611 is turned over by an angle α, α=110° -150 °.

In the present embodiment, the fitting plane 1611 is used to fit the headrest stay 5 to form the main body structure of the headrest.

Specifically, as shown in fig. 1 to 3, the base plate 11, the first driving plate 12, the second driving plate 13, and the second extending plate 15 form a planar four-bar mechanism, the first driving plate 12, the second extending plate 15, the mounting plate 16, and the first extending plate 14 constitute another planar four-bar mechanism, other bars constituting the two planar four-bar mechanisms are movably installed except for the fixed installation of the base plate 11, and the degree of freedom of the headrest adjusting structure is 1, so that the adjustment of the posture of the headrest adjusting structure can be realized by driving other bars except for the base plate 11. In this embodiment, the headrest support plate 5 is assembled on the assembling plane 1611, that is, in the adjustment process of the headrest adjusting structure, the angle rotated by the assembling plane 1611 is the same as the angle rotated by the headrest support plate 5, that is, the angle range of the headrest that can be adjusted by the headrest adjusting structure. In this embodiment, headrest adjusts simple structure, can realize the regulation of headrest wide angle scope, satisfies the user demand.

Further, α=120° -134 °. Preferably, α=127°. When the turnover angle of the assembly plane 1611 is about 127 °, the headrest angle that the headrest adjusting structure can adjust correspondingly can meet the user's needs, and the overall width is moderate in the headrest adjusting structure posture adjusting process, occupies small space inside the seat unit, also means that the volume of the seat unit can be reduced in the headrest adjusting structure assembly area, and the space occupation ratio when the seat unit is arranged is reduced.

In this embodiment, as shown in fig. 4, the first extension plate 14 is located outside the second extension plate 15, the shortest rod section of the second extension plate 15 located between the mounting plate 16 and the first driving plate 12 is defined as a working section, the outer edge of the working section near one side of the first extension plate 14 is defined as a working edge 151, and when the headrest adjusting structure is switched between the storage state and the extension state, and viewed from the outside of the first extension plate 14 toward the direction of the second extension plate 15, the first extension plate 14 can shield the working edge 151. So set up, in the view angle from outside to inside to headrest adjusting structure, can prevent to the maximum extent that the clearance from appearing between first extension board 14 and the second extension board 15, improved headrest adjusting structure's compactibility of structure, increased headrest adjusting structure's structural strength to a certain extent, can effectively prevent simultaneously that there is the foreign matter entering between first extension board 14 and the second extension board 15, the security is high.

In this embodiment, as shown in fig. 1 and 2, a limiting member 121 is disposed on the first driving plate 12, and the limiting member 121 is located between the first pivot point a and the base plate 11; when the headrest adjusting structure is in the housed state and the extended state, the outer edge of the side of the second extension plate 15 facing away from the first extension plate 14 abuts against the stopper 121. The side edge of the second extension plate 15 facing the limiting member 121 is configured into an arc shape protruding towards the limiting member 121, the second extension plate 15 rotates around the first pivot point a compared with the first driving plate 12, and after the second extension plate 15 rotates and abuts against the limiting member 121, two limit states, namely a storage state and an extension state are maintained.

As shown in fig. 2, the connection point between the first driving plate 12 and the base plate 11 is a second pivot point b, and the connection point between the first driving plate 12 and the first extending plate 14 is a third pivot point c; the first rotating shaft where the first pivot point a is located, the second rotating shaft where the second pivot point b is located, and the third rotating shaft where the third pivot point c is located are parallel to each other, the distance between the orthographic projections of the first pivot point a and the second pivot point b in the first rotating shaft direction is D1, the distance between the orthographic projections of the first pivot point a and the third pivot point c in the first rotating shaft direction is D2, d1:d2=2-2.6, preferably d1:d2=2.303.

Preferably, the limiting piece 121 is a limiting shaft, and the axial direction of the limiting shaft is parallel to the axial direction of the first rotating shaft; the shortest distance between the second pivot point b and the limiting shaft is D3, the shortest distance between the third pivot point c and the limiting shaft is D4, and D3:D4=1-1.5. Further, d3:d4=1.2-1.4. Preferably d3:d4=1.257.

Preferably, the limiting shaft is cylindrical, and is matched with the arc-shaped side edge of the second extending plate 15 facing the limiting piece 121 to realize line contact, so that the contact area of the limiting shaft and the limiting plate is increased, and the safety is high.

In the present embodiment, the mounting plate 16 includes a mounting portion 161 and a fixing portion 162 that are connected to each other, and the first extension plate 14 and the second extension plate 15 are both connected to the fixing portion 162; when the headrest adjusting structure is in the housed state, the base plate 11 is on the back side of the mounting portion 161; when the headrest adjusting structure is in the extended state, the base plate 11 is on the face side of the mounting portion 161. The mounting portion 161 and the fixing portion 162 are integrally formed, and are both plate materials. The fixing portion 162 is parallel to the first extension plate 14 and the second extension plate 15, and as shown in fig. 4, the fixing portion 162 is located between the first extension plate 14 and the second extension plate 15 and the first driving plate 12 is located between the first extension plate 14 and the second extension plate 15 in the outside-in direction.

Further, a fitting plane 1611 is provided on the face side of the mounting portion 161; defining a connection point between the first driving plate 12 and the base plate 11 as a second pivot point b, a connection point between the second driving plate 13 and the base plate 11 as a fourth pivot point d, wherein a second rotating shaft where the second pivot point b is positioned is parallel to a fourth rotating shaft where the fourth pivot point d is positioned, and an included angle between a connecting line between orthographic projection of the second pivot point b and the fourth pivot point d in the axial direction of the second rotating shaft and the assembly plane 1611 is beta; when the headrest adjusting structure is in the stowed state, β=80° -100 °; when the headrest adjustment structure is in the extended state, β=30° -50 °. For convenience of description, as shown in fig. 1, when the headrest adjusting structure is in the storage state, an included angle between a connecting line between orthographic projections of the second pivot point b and the fourth pivot point d in the axial direction of the second rotating shaft and the assembling plane 1611 is β1, that is, β1=80 ° -100 °; as shown in fig. 2, when the headrest adjusting structure is in the extended state, an angle between a line between the orthographic projection of the second pivot point b and the fourth pivot point d in the second rotation axis direction and the fitting plane 1611 is β2, that is, β2=30° -50 °.

Still further, β1=85 ° -95 ° -when the headrest adjusting structure is in the stowed state; when the headrest adjustment structure is in the extended state, β2=35° -45 °. Preferably β1=88°, β2=39°. In this embodiment, the connection line between the orthographic projection of the second pivot point b and the fourth pivot point d in the axial direction of the second rotation shaft extends basically along the longitudinal direction, or is parallel to the extending direction of the backrest of the seat unit, β1=88°, β2=39°, so that when the headrest adjusting structure is in the storage state, the assembly plane 1611, i.e. the headrest support plate 5, faces away from the base plate 11 and is basically perpendicular to the extending direction of the backrest, so that the headrest can be completely stored to vacate the space at the top of the backrest, thereby effectively reducing the height of the seat unit and facilitating the storage and transportation of the seat unit; and when the headrest adjusting structure is in an extending state, the assembling plane 1611, namely the headrest support plate 5, is turned back to the side, facing the substrate 11, of the substrate 11, so that large-angle rotation of the headrest support plate 5 can be realized, the height of a backrest of the seat unit is improved, the backrest of a user is supported in a larger area, and the comfort level of the seat unit is improved.

In the present embodiment, when the headrest adjusting structure is switched between the housed state and the extended state, the minimum height difference of the fitting plane 1611 is H, h=70 mm to 120mm. Preferably, h=98.49 mm. The fitting plane 1611, i.e., the headrest stay 5, is thus provided with a large adjustable range in the longitudinal direction, so that the seat unit provided with the headrest adjusting structure has a large adjustable range in the longitudinal direction (the backrest extending direction), thereby facilitating the accommodation of the seat unit.

As shown in fig. 1, the distance between the second rotation axis and the fourth rotation axis is D5, d5=65 mm-75mm. Further, d5=70 mm-73mm. Preferably d5=72 mm.

The present embodiment also provides a seat unit including the headrest side plate 4 and the headrest adjusting structure described above, and the base plate 11 is mounted inside the headrest side plate 4. In the present embodiment, as shown in fig. 5 and 6, the headrest side plates 4 are provided in two mirror images, which correspond to the two headrest adjusting structures provided in the mirror images one by one. Specifically, the base plate 11 of the headrest adjusting structure is fixedly mounted on the inner side surface of the headrest side plate 4 by bolts or screws, the first beam 21 and the second beam 22 are located between the two headrest side plates 4, the end portion of the first beam 21 is correspondingly connected to the base plate 11, the end portion of the second beam 22 is provided with an adapter plate 221, and the adapter plate 221 is pivotally connected to the second driving plate 13. In this embodiment, the driving member 3 is preferably a linear actuator, and is fitted between the first beam 21 and the second beam 22, and drives the headrest adjusting structure to act through the second beam 22. The seat unit is convenient for storage and transportation.

In other embodiments, the adapter plate 221 may also be selectively pivotally connected to the first drive plate 12, the first extension plate 14, the second extension plate 15, or the mounting plate 16. The reason why the second drive plate 13 is preferable in this embodiment is that the second drive plate 13 is located inside the first drive plate 12 and closer to the first cross member 21, so that the length of the linear actuator can be shortened, which is advantageous in ensuring rigidity and reliability thereof.

The technical means disclosed by the scheme of the utility model is not limited to the technical means disclosed by the embodiment, and also comprises the technical scheme formed by any combination of the technical features. It should be noted that modifications and adaptations to the utility model may occur to one skilled in the art without departing from the principles of the present utility model and are intended to be within the scope of the present utility model.

Claims

1. The utility model provides a headrest adjusts structure, its characterized in that includes base plate (11), first drive plate (12), second drive plate (13), first extension board (14), second extension board (15), mounting panel (16) and driving piece, wherein:

One end of the first driving plate (12) is pivotally connected to the base plate (11), the other end of the first driving plate (12) is pivotally connected to the first extension plate (14), and the first extension plate (14) is pivotally connected to the mounting plate (16);

One end of the second driving plate (13) is pivotally connected to the base plate (11), the other end of the second driving plate (13) is pivotally connected to the second extension plate (15), and the second extension plate (15) is pivotally connected to the mounting plate (16);

The first driving plate (12) is pivotally connected with the second extending plate (15), and the connection point of the first driving plate and the second extending plate is a first pivot point (a) and is positioned between two end parts of the first driving plate (12);

The driving piece acts on any one of the first driving plate (12), the second driving plate (13), the first extension plate (14), the second extension plate (15) and the mounting plate (16) to switch the headrest adjusting structure between a storage state and an extension state;

the mounting plate is provided with a fitting plane, and when the headrest adjusting structure is switched between the storage state and the extended state, the turning angle of the fitting plane (1611) is alpha, alpha=110 DEG to 150 deg.

2. The headrest adjusting structure according to claim 1, wherein α = 120 ° -134 °.

3. The headrest adjusting structure according to claim 1, characterized in that the first extension plate (14) is located outside the second extension plate (15), a shortest rod section of the second extension plate (15) located between the mounting plate (16) and the first driving plate (12) is defined as a working section, an outer edge of the working section near one side of the first extension plate (14) is a working edge (151), and the first extension plate (14) can shield the working edge (151) when the headrest adjusting structure is switched between the storage state and the extension state and is seen from the outside of the first extension plate (14) toward the direction of the second extension plate (15).

4. The headrest adjusting structure according to claim 1, characterized in that a stopper (121) is provided on the first drive plate (12), the stopper (121) being located between the first pivot point (a) and the base plate (11);

When the headrest adjusting structure is in the storage state and the stretching state, the outer edge of one side of the second extension plate (15) facing away from the first extension plate (14) is abutted to the limiting piece (121).

5. The headrest adjusting structure according to claim 4, wherein a connection point of the first driving plate (12) and the base plate (11) is a second pivot point (b), and a connection point of the first driving plate (12) and the first extending plate (14) is a third pivot point (c);

The first rotating shaft where the first pivot point (a) is located, the second rotating shaft where the second pivot point (b) is located and the third rotating shaft where the third pivot point (c) is located are parallel to each other, the distance between orthographic projections of the first pivot point (a) and the second pivot point (b) in the axial direction of the first rotating shaft is D1, and the distance between orthographic projections of the first pivot point (a) and the third pivot point (c) in the axial direction of the first rotating shaft is D2, d1:d2=2-2.6.

6. The headrest adjusting structure according to claim 5, wherein the stopper (121) is a stopper shaft, an axial direction of which is parallel to an axial direction of the first rotating shaft;

The shortest distance between the second pivot point (b) and the limiting shaft is D3, and the shortest distance between the third pivot point (c) and the limiting shaft is D4, d3:d4=1-1.5.

7. The headrest adjusting structure according to claim 6, wherein d3:d4=1.2-1.4.

8. The headrest adjusting structure according to claim 1, characterized in that the mounting plate (16) includes a mounting portion (161) and a fixing portion (162) that are connected to each other, the first extension plate (14) and the second extension plate (15) being both connected to the fixing portion (162);

When the headrest adjusting structure is in the housed state, the base plate (11) is on the back side of the mounting portion (161); when the headrest adjusting structure is in the extended state, the base plate (11) is on the face side of the mounting portion (161).

9. The headrest adjusting structure according to claim 8, wherein the fitting plane (1611) is provided on a face side of the mounting portion (161);

Defining a connection point between the first driving plate (12) and the base plate (11) as a second pivot point (b), wherein a connection point between the second driving plate (13) and the base plate (11) is a fourth pivot point (d), a second rotating shaft where the second pivot point (b) is positioned is parallel to a fourth rotating shaft where the fourth pivot point (d) is positioned, and an included angle between a connecting line between orthographic projection of the second pivot point (b) and the fourth pivot point (d) on the axial direction of the second rotating shaft and the assembling plane (1611) is beta;

When the headrest adjusting structure is in the stowed state, β=80° -100 °;

when the headrest adjustment structure is in the extended state, β=30° -50 °.

10. The headrest adjusting structure according to claim 9, wherein,

When the headrest adjusting structure is in the stowed state, the β=85° -95 °;

when the headrest adjustment structure is in the extended state, the β=35° -45 °.

11. The headrest adjusting structure according to claim 9, wherein a distance between the second rotation shaft and the fourth rotation shaft is D5, d5=65 mm to 75mm.

12. The headrest adjusting structure according to claim 11, wherein d5=70 mm-73mm.

13. The headrest adjustment structure according to any one of claims 1-12, characterized in that the minimum height difference of the fitting plane (1611) is H, the H = 70mm-120mm, when the headrest adjustment structure is switched between the stowed and extended states.

14. A seat unit comprising a headrest side plate and a headrest adjusting structure as claimed in any one of claims 1 to 13, said base plate (11) being mounted inside said headrest side plate.