JPH0459439A - Device for finely adjusting inclination of upper reclining backrest in reclining backrest seat for vehicle - Google Patents

Abstract

PURPOSE:To make the pivoting of an upper backrest part interlock with the forward and backward turning movement of a lower backrest part for the prevention of troubles by dividing a backrest seat into the upper and lower backrest parts to provide a reversible toumel mechanism between the lower backrest part and a seat and the toumel mechanism with a device for finely adjusting inclination between the upper and lower backrest parts. CONSTITUTION:A reclining mechanism A is disposed by lower reversible toumel mechanisms 19, 19 between a seat 2 and a lower backrest part 4. Upper toumel mechanisms 42, 42 are provided between the lower and upper backrest parts 4, 5. A fine adjustment device 60 is mounted on the outer end of an upper rotary shaft 49 of the upper toumel mechanism 42 to finely adjust the inclination of the upper backrest part 5 by direct turning movement with upper inner peripheral teeth 49. Also, the upper rotary shaft 49 of the upper toumel mechanism 42 is interlocked with a lower rotary shaft 26 of the lower reversible toumel mechanism 19 through a rotary transmission member 58, driven gear 57 and intermediate drive gear 34 so that the upper backrest part 5 is inclined by the forward and backward turning movement of the lower backrest part 4.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a device for adjusting the inclination angle of an upper backrest portion of a backrest seat for a vehicle.

(Prior art) Japanese Patent Application Laid-Open No. 60-193729 discloses that the back seat is composed of a seat attached to the vehicle body side and a backrest seat attached to the rear of the seat so as to be rotatable back and forth. The canopy seat is divided into a lower backrest portion and an upper backrest portion, the lower backrest portion is pivotally fixed to the seat sheet so as to be rotatable back and forth, and the upper backrest portion is connected to the lower backrest portion. A vehicle backrest seat is configured such that the lower backrest portion is pivotally fixed to the backrest portion so as to be rotatable back and forth, and when the lower backrest portion is rotated back and forth, the upper backrest portion is rotated back and forth in conjunction with this, A parallel link mechanism connects the bracket a of the seat and the arm C of the upper backrest frame b by a connecting rod e parallel to the lower backrest frame d, and the connecting rod e.
A handle f that rotates a cam member provided on the lower shaft support of
A device for finely adjusting the inclination angle of the upper backrest portion of a vehicle backrest seat provided with the above is described (see Fig. 14).
.

(Problem to be Solved by the Invention) The known device for finely adjusting the inclination angle of the upper backrest portion is as follows:
Since the seat bracket (a) and the arm C of the paired upper backrest frame b are connected in a parallel link mechanism by the lower backrest frame d, which also serves as a rod, and the connecting rod e, When the handle f of the lower shaft support of the connecting rod e is rotated, the connecting rod 2 moves up and down and the arm C rotates left and right in the figure, so that the upper backrest frame b can be tilted forward or backward. Can be finely adjusted.

However, in the configuration mentioned above, there is no need to worry about the tensile strength of the connecting rod e, but there is no way to ensure the compressive strength other than increasing the diameter of the connecting rod e. This increases weight, costs, and is difficult.

Therefore, other structures have been carefully devised, and fine adjustments can be made using a simple method.

(Objective of the Invention) Therefore, the first object of the present invention is to obtain an apparatus for adjusting the inclination angle of an upper backrest that is less likely to malfunction by utilizing the known Taumel mechanism.

A second object of the present invention is to enable fine adjustment in the device for adjusting the inclination angle of the upper backrest using the known Taumel mechanism.

(Means for Solving the Problems) Therefore, the present invention comprises a seat 2 attached to the vehicle body side and a back seat 3 attached to the rear of the seat 2 so as to be rotatable back and forth. 3 is divided into a lower backrest portion 4 and an upper backrest portion 5, the lower backrest portion 4 is pivotally fixed to the seat 2 so as to be rotatable back and forth, and the northern backrest portion 5 is The lower backrest part 4 is pivoted so as to be rotatable back and forth, and the lower backrest part 4 side has lower peripheral teeth 21 at the pivoting part between the lower backrest part 4 and the seat sheet 2. A lower reversing Taumel mechanism 19 is provided in which the seat seat 2 side has a lower inner circumferential tooth n, and the upper backrest part 5 side has an upper inner circumferential tooth n at the shaft stop between the upper backrest part 5 and the lower backrest part 4. A one-L part Taumel mechanism C is provided which is a toothed part and has an upper outer circumferential tooth U on the side facing the lower backrest, and the lower outer circumferential tooth 21 of the lower reversing Taumel mechanism 19 and the upper inner circumferential tooth part of the upper Taumel mechanism C are provided. A rotary transmission part foundation is provided between the parts, so that when the lower backrest part 4 is rotated back and forth, the upper backrest part 5 is rotated back and forth in the opposite direction in conjunction with the lower backrest part 4. The upper inner circumferential tooth portion of the upper backrest portion 5 is provided with the upper inner circumferential groove 46.
This is a device for finely adjusting the inclination angle of the upper backrest portion of a vehicle backseat, which is equipped with a finely adjusting device (9) that can directly rotate the backrest.

(Embodiment) To explain an embodiment of the present invention with the drawings, 1 is a vehicle seat, 2 is a seat of the vehicle seat 1, and 3 is a backrest that is attached to the rear of the seat 2 so as to be rotatable back and forth. It is a sheet.

The backrest sheet 3 includes a lower backrest portion 4 that supports the lower back and waist, and an upper backrest portion 5 that supports the upper back.
It is formed in two parts.

In FIG. 2, 7 is a lower skeleton frame of the lower backrest portion 4, which includes an upper horizontal frame 8, a lower horizontal frame 9, and the upper horizontal frame 8.
and a lower vertical frame 10.10 which connects and fixes both ends of the lower horizontal frame 9, forming a rectangular frame shape.

Reference numeral 11 denotes an upper skeleton frame of the upper backrest portion 5, which, like the lower skeleton frame 7, includes an upper horizontal frame ν and a lower horizontal frame 13.
The upper horizontal frame 14 and the upper vertical frame 14 and 14 which connect and fix both ends of the lower horizontal frame 13 form a rectangular frame shape.

Each vertically long mounting plate 15.15 is fixed to the lower vertical frame 10.10, and the upper part of each vertically lower movable bracket h16.16 is fixed to the lower end of each mounting plate 15.15 with bolts or the like. Fix it.

The lower portion of each of the lower tray moving brackets 16 and 16 is connected to a lower fixing bracket 1 fixed to the rear side of the seat 2.
8.18, each of which is pivoted so as to be rotatable in the front and rear directions.

Between the left and right lower movable brackets 16 and the lower fixing brackets 18, there are provided lower reversing mechanisms 19 and 19, which constitute a reclining mechanism A that adjusts the inclination angle of the lower backrest 4.

The lower part of the lower movable bracket 16 is formed with a convex part 20 which is bent into an arcuate cross-section and has a circular shape in side view (Figs. 3 and 4), and a lower part is formed on the outer peripheral surface of the convex part. The outer peripheral teeth 21 are formed.

The lower fixing bracket eye 8 is formed with a recess η having a rectangular cross-section and a circular shape in side view, protruding inward from the convex portion side with a larger diameter, and a recess η having a circular shape in side view is formed on the inner circumferential surface of the recess η. Form periodontal teeth n.

The convex side is fitted into the recess η so that the lower outer tooth 21 partially meshes with the lower inner tooth B (FIG. 3).

A fitting hole 24 is formed in the center of the four parts n (Fig. 4),
A fitting hole is formed in the center of the convex portion side, and the fitting hole 2
4, and the lower rotating shaft side in the left-right direction is inserted and fitted into the fitting hole.

The lower rotating shaft side has a small diameter shaft part n and a small diameter shaft part n on the left and right sides with the large diameter cam shaft part n in between.The large diameter cam shaft part n is connected to the small diameter shaft part n, 29. The small diameter cam shaft part N is fitted into the fitting hole 24, and the large diameter cam shaft part N is fitted into the fitting hole B.

By rotating eccentrically with respect to the small diameter shaft part 1.29, the large diameter cam shaft part n exerts a cam action that moves the lower outer circumferential teeth 21 while meshing with the lower inner circumferential teeth B (FIG. 8).

The insertion hole 31 of the reinforcing plate I is inserted into the small diameter shaft portion 6, and the reinforcing root wall is provided at the outer side of the lower movable bracket 16, and the lower movable bracket 16 is fixed to the left and right sides by the lower fixing bracket 18 and the reinforcing plate I. Clamp from the 32 is a holding pin that smoothes the rotation of the lower movable bracket 16;
The lower movable bracket 16 is fixed at a predetermined interval to the upper part of the lower movable bracket 16, and the lower fixed bracket tg is sandwiched between the pin support and the lower movable bracket 16.

As shown in FIG. 3, the outer end of the small-diameter shaft member is made to protrude outward from the reinforcing wall, and the intermediate gear blade is fixed to the small-diameter shaft member. The intermediate gear blade rotates on the same axis as the small diameter shaft component.

Further, an intermediate drive gear a is fixed to the outer end of the small diameter shaft portion n. ``The intermediate drive gear is mounted eccentrically with respect to the small diameter camshaft so that it rotates on the same axis as the large diameter camshaft.

An input gear that meshes with the intermediate gear blade is mounted on the lower fixing bracket ts by a shaft, and a reclining dial 37 is fixed to the shaft 36.

Both ends of a connecting shaft in the left and right direction are fixed to the small diameter shaft portion n of each of the left and right lower reversing Taumel mechanisms 19, and the lower reversing Taumel mechanisms 19.
19 are activated at the same time.

As described above, the lower reversal Taumel mechanism 19 includes the convex side of the lower movable bracket 16, the lower outer circumferential tooth 21 on the outer peripheral surface of the convex side, and the concave part η of the lower fixed bracket eye 8. , lower inner peripheral teeth n formed on the inner peripheral surface of the recess η,
The lower backrest portion 4 is composed of the lower rotating shaft side and
Said reclining dial π so as to tilt back.
When rotated clockwise in FIG. 4, the rotation is transmitted to the lower rotating shaft by the input gear and the intermediate gear, and the lower rotating shaft itself rotates counterclockwise and the lower outer peripheral teeth 21 also rotate as shown in FIG. 8. It itself rotates counterclockwise in the same way as the lower rotating shaft side, but due to this rotation, the lower outer circumferential tooth 21 moves in the clockwise direction along the lower inner circumferential tooth B, and the lower reversing Taumel mechanism 19
The lower backrest portion 4 is rotated in the rotational direction of the reclining dial g by the counterclockwise movement of the lower outer circumferential teeth 21.

At the upper end of each of the mounting plates 15.15, there is a vertically elongated upper fixing bracket 40, which fixes the lower part of each of the chestnuts (Fig. 3), and an upper fixing bracket (40.40).
At the top of each of the L-portion moving brackets 41 . fixed to the upper vertical frame 14 . 14 of the upper frame 11 .
41 are pivoted so as to be freely rotatable in the front and rear directions.

A lower backrest portion 4 is provided between the left and right upper fixed brackets 40 and the left and right upper movable brackets 41.
In contrast, upper Taumel mechanisms C and 42 are provided, respectively, constituting an upper backrest tilting mechanism B for tilting the upper backrest portion 5 forward (FIG. 2).

The upper backrest tilting mechanism B includes the lower reversing Taumel mechanism 19.
When the entire backrest seat 3 is rotated backwards, the lower backrest part 4 tilts backward, but the seven-part backrest part 5 is a mechanism that causes it to fall forward.

As shown in FIG. 5, a convex portion 43 having a rectangular cross section is formed on the upper portion of the upper fixing bracket hammer, and an upper outer circumferential groove is formed on the outer peripheral surface of the convex portion 43.

The upper movable bracket 41 is formed with a recess 6 having a box-shaped cross section that is recessed inward, and upper inner peripheral teeth 6 that partially mesh with the upper outer peripheral teeth a are formed on the inner peripheral surface of the recess 6.

A fitting hole 47 is formed at the center of the convex portion 43, a fitting hole hammer is formed at the center of the recess 6, and the large diameter shaft portion 51 of the upper rotating shaft is fitted into the fitting hole 47. Match.

The upper rotary shaft 49 has a small diameter camshaft (part) formed at its inner end, a different diameter shaft part (part) formed at its outer end, and the small diameter camshaft (part) is connected to the large diameter shaft part 51. and is formed eccentrically with respect to the different diameter shaft portion 52.

The space between the small diameter cam shafts is inserted into the fitting hole of the upper movable bracket 41, and the end between the connecting shafts is fixed to the inner end of the small diameter cam shaft. The upper Taumel mechanism C is activated at the same time.

The insertion hole I of the upper reinforcing plate is inserted into the large diameter shaft portion 51, and the upper reinforcing plate is provided outside the upper fixing bracket 40. Hold it from the left and right sides. 56
is a holding pin that holds down the lower end of the upper movable bladder 2 41, and is fixed to the lower part of the upper fixed bracket 7 40 at a predetermined interval. ) 41.

As described above, the upper Taumel mechanism P includes the convex portion of the upper fixed bracket 40, the upper outer circumferential teeth U formed on the outer circumferential surface of the convex portion, and the concave portion 45 of the upper movable bracket 41.
The upper movable bracket 41 is constituted by an upper inner circumferential tooth portion formed on the inner peripheral surface of the recess 6 and an upper rotating shaft, and the upper movable bracket 41 is rotated in the same direction as the rotating direction of the upper rotating shaft.

The large diameter shaft portion 51 of the upper rotating shaft chestnut has a large diameter shaft portion 51.
Pass through the passive gear 57 coaxially so that it can only rotate freely,
Between the passive gear 57 and the intermediate drive gear, a rotary transmission unit consisting of a timing belt or the like is connected, and the upper Taumel mechanism C is connected to the lower reversing Taumel mechanism 19.
Link with.

A fine adjustment device is provided at the outer end of the upper rotating shaft 49.

A housing 61 having a circular inner peripheral surface is fixed to the outer surface of the driven gear 57. The different diameter shaft portion 52 of the upper rotating shaft is made to protrude into the housing 61, and a plate filling having an outwardly bent protrusion P is fitted into the different diameter shaft portion.

A part of the outer circumferential surface of the zero-rotating body piece is made to protrude outward from the plate 63, and a regular cylindrical rotating body is rotatably fitted into the protrusion. A notch is formed in the axial direction of - to form an engagement groove 5, and the protrusion of the play E+ is engaged with the engagement groove 5.

A shaft portion projecting outward is formed at the center of the outer surface of the rotating body, and the shaft portion I projects outward from the center of the housing 61, and a fine adjustment handle is fixed to the projection portion.

Further, a coiled spring lock is inserted between the inner circumferential surface of the housing 61 and the outer circumferential surface of the rotating body. The spring lock is attached to the inner peripheral surface of the housing 61, and between the ends of the spring lock,
69 is engaged with the retaining groove of the rotating body.

The fine adjustment device (equipment) uses the fine adjustment handle opening to adjust the rotating body.
When rotated, the end 6 of the engagement groove and spring screw in the figure of the rotating body
9 and rotate it to reduce the diameter of the spring,
At the same time, rotate the protrusion of (play) E (without rotating the housing 61 and the passive gear 57. play)
The rotation of E3 causes the upper rotating shaft 49 to rotate, thereby operating the L-portion Taumel mechanism C.

In addition, in the relationship between the lower outer circumferential tooth 21, the upper outer circumferential tooth, and the lower inner circumferential tooth n, and the upper inner circumferential tooth Tsukuda, the number of teeth and the pitch may be different, or the intermediate drive gear and the passive gear 57 may be different. By changing the gear ratio of It is also possible to cause the lower backrest portion 4 to move in parallel, or to cause the lower backrest portion 4 to fall forward suddenly relative to the backward reclining state.

Further, an electric motor may be attached to the handle 37 instead of a nail.

(effect) Next, we will discuss the effect.

The present invention has the above-described configuration, and the backrest seat (3) is vertically divided into a lower backrest portion 4 and an upper backrest portion 5, and a lower movable bracket of the lower frame 7 of the lower backrest portion 4. 1
6 is pivotally fixed to the lower fixed bracket 18 of the seat 2 so as to be rotatable back and forth, and the lower movable bracket 16 is formed with lower outer circumferential teeth 21, and the lower outer circumferential teeth 21 are attached to the lower fixed bracket 18. Since it partially engages with both inner circumferential concave portions, when seated on the vehicle seat 1, the reclining dial 37 of the reclining mechanism A is pressed against the lower backrest portion 4.
When it is rotated clockwise in the direction shown in FIG. 4 in which the gear is tilted backwards, the rotation is transmitted by the manual gear and the intermediate gear blade, and the lower rotating shaft itself rotates counterclockwise, and the lower outer circumferential tooth 21 also rotates counterclockwise.
As shown in the figure, it rotates counterclockwise in the same way as the lower rotating shaft, but due to this rotation, the lower outer circumferential teeth 21 move in the clockwise direction along the lower inner circumferential concavities, and the lower reversing Taumel mechanism 19 rotates as described above. The counterclockwise movement of the lower outer circumferential teeth 21 causes the lower backrest portion 4 to be tilted rearward in the same direction as the rotation direction of the reclining dial π.

Thus, the upper backrest 5's upper skeleton frame 11 is pivotally fixed to the upper part of the lower skeletal frame 7 of the lower backrest 4 via the upper backrest inclination mechanism B so as to be rotatable back and forth. The tilting mechanism B is configured by forming an upper outer periphery on the upper fixed bracket ω of the lower skeletal frame 7 and forming an upper inner periphery tooth on the upper movable bracket 41 of the upper skeletal frame 11. The rotation of the lower rotating shaft rotates the intermediate gear blade, and the rotation of the intermediate gear is transmitted to the passive gear 57 by the rotation transmission unit foundation, the passive gear 57 rotates the housing 61, and the housing 61 rotates the housing 61.
The spring 68 that is attached to the inner circumferential surface of the rotating body is rotated, and one end wing of the spring piece engages with the engagement groove 6 shown in the figure of the rotating body.
The rotating body diagram rotates the protrusion that is necessarily engaged with the retaining groove, the protrusion rotates the plate 63, and the plate 8 rotates between the upper rotating shafts via the different diameter shaft part 52. let

When the upper rotating shaft Q of the upper Taumel mechanism C of the upper backrest tilting mechanism B is rotated, the L rotating shaft rotates the small diameter cam shaft part eccentrically with respect to the large diameter shaft part 51, and the small diameter cam The shaft part rotates while engaging the upper inner circumferential teeth with the upper outer circumferential teeth.

The upper inner circumferential tooth portion rotates counterclockwise as shown in FIG. Let it fall down, the L skeleton frame!
The upper backrest portion 5 is tilted forward via the l.

Therefore, when the lower backrest 4 tilts backward, the upper backrest 5 falls forward, and the upper back of the seated person is supported by the upper backrest 5, maintaining a comfortable posture.

Therefore, the outer end of the upper rotating shaft 49 has a fine adjustment cylinder bag N.
60, between the fine adjustment devices, when the rotating body is rotated by the fine adjustment handle, the engagement groove of the rotating body engages with one end of the spring tab and rotates. , the diameter of the spring pin is reduced, and at the same time the protrusion of the plate 8 is rotated without rotating the housing 61 and the passive gear 57, the upper rotation axis is rotated by the rotation of the plate 63, and the upper rotation axis 0 is rotated. As described above, the upper Taumel mechanism C is activated to rotate the upper backrest 5 back and forth to a desired angle, thereby finely adjusting the inclination angle of the upper backrest 5.

(Effect) In the conventionally known Japanese Patent Application Laid-Open No. 1983-193729, a lower part which also serves as a rod is provided between the arm C of the two-part backrest frame b, which is paired with the bracket y)a of the seat. Since the backrest frame d and the connecting rod e are connected to a parallel link mechanism, when the handle f of the lower shaft support of the connecting rod e is rotated, the connecting rod e moves up and down, and the arm C moves in the direction shown in the figure. The upper backrest frame b can be finely adjusted to tilt forward or backward because it rotates left and right at There is no other way to ensure strength than making it thicker, but increasing the diameter of the rows and holes e increases weight and cost, which is difficult.

However, the present invention comprises a seat 2 attached to the vehicle body side, and a backrest 3 attached to the rear of the seat 2 so as to be rotatable back and forth, and the backrest 3 has a lower backrest 4.
The lower backrest part 4 is pivotally fixed to the seat 2 so as to be rotatable back and forth, and the upper backrest part 5 is connected to the lower backrest part 4. The lower backrest part 4 and the seat sheet 2 are pivoted so as to be rotatable back and forth, and the lower backrest part 4 side has a lower outer circumference tooth 21 and the seat sheet 2 side has a lower inner circumference tooth 21. A lower reversing Taumel mechanism 19 with teeth n is provided, and the upper backrest part 5 and the lower backrest part 4
An upper Taumel mechanism 42 in which the upper backrest 5 side is an upper inner circumferential gear and the lower backrest 4 side is an upper outer circumferential gear is provided at the shaft stop part, and a lower part of the lower reversing Taumel mechanism 19 is provided. A rotation transmission member is provided between the outer peripheral teeth 21 and the inner peripheral teeth of the L section of the upper Taumel mechanism C, and when the lower backrest 4 is rotated back and forth, the upper backrest 5 moves in conjunction with this. is configured to rotate back and forth in opposite directions,
The upper inner toothed portion of the upper backrest portion 5 is provided with a fine adjustment device for finely adjusting the inclination angle of the upper backrest portion in a vehicle backrest seat, which is provided with a fine adjustment device that can directly rotate the upper inner toothed portion. Therefore, (a) the inclination angle of only the upper backrest portion 5 can be finely adjusted between the fine adjustment devices provided at the shaft stop portions of the upper backrest portion 5 and the lower backrest portion 4;

The fine adjustment device (equipment) is provided at the shaft stop between the upper backrest part 5 and the lower backrest part 4, and directly rotates the upper inner circumferential gear, so there is no need to worry about the strength, so there is no need to worry about failure. It has a simple structure and is easy to assemble.

This effect is achieved.

[Brief explanation of drawings]

Fig. 1 is a perspective view of the vehicle seat, Fig. 2 is a perspective view of the frame of the vehicle seat, Fig. 3 is a longitudinal sectional front view of main parts, Fig. 4 is an assembled perspective view of the lower reversing Taumel mechanism, Fig. 5 is an assembled perspective view of the upper Taumel mechanism, FIG. 6 is a side view of the lower reversing Taumel mechanism, FIG. 7 is a side view of the upper Taumel mechanism, and FIG. 8 is a side view of the upper Taumel mechanism.
Figures 9 and 9 are explanatory diagrams of the action of the Taumel mechanism, Figures 10 to 13 are diagrams of its working state, and Figure 14 is a diagram of a known example. Explanation of symbols 1...vehicle seat, 2...seat sheet, 3...
Backrest sheet, 4...Lower backrest part, 5...Upper backrest part, 7...Lower skeleton frame, 8...Upper horizontal frame, 9.
...Lower horizontal frame, 10...Lower vertical frame, ll...Upper skeleton frame, Minister...Upper horizontal frame, 13...Lower horizontal frame,
14... Upper vertical frame, 15... Mounting plate, 16... Lower moving bracket, 18... Lower fixing bracket, 1
9...Lower reversal Taumel mechanism, redundant...convex portion, 21.
...Outer tooth, η...concavity, B...inner tooth, 24.5
...Fitting hole, 9...Lower rotation shaft, n...Small diameter shaft section, redundancy...Large diameter cam shaft section, 3...Small diameter shaft section, (9)
... Reinforcement plate, 31 ... Insertion hole, 32 ... Holder pin, feather ... Intermediate gear, A ... Intermediate drive gear, A ...
Input gear, I...shaft, g...reclining dial, wing...connection shaft, 40...upper fixing bracket,
41... Upper movable bracket, C... Upper Taumel mechanism, invitation... Convex portion, weak... Outer tooth, 45... Concave portion, 46... Inner tooth, 47.48... Fitting hole, 49・
・・Upper rotating shaft, (capital) ・・Small diameter cam shaft part, 51・・
・Large diameter shaft part, 52...Different diameter shaft part, jumper...connection shaft, leg...upper reinforcing plate, 6...insertion hole, group...holding pin, 57...passive gear ,...Rotating transmission member, mark...
... Fine adjustment device, 61 ... Housing, Dry ... Protrusion, Field ... Plate, 8 ... Rotating body, I ... Engagement groove, Hammer ... Shaft part, "... Fine adjustment handle, simple... spring, 59... end. 2 people outside ゛1''

Claims (1)

[Claims] It consists of a seat 2 attached to the vehicle body side, and a back seat 3 attached to the rear of the seat 2 so as to be rotatable back and forth,
The backrest seat 3 is divided into a lower backrest part 4 and an upper backrest part 5, the lower backrest part 4 is pivoted to the seat sheet 2 so as to be rotatable back and forth, and the upper backrest part 4 is rotatably fixed to the seat sheet 2. The part 5 is pivotally fixed to the lower backrest part 4 so as to be rotatable back and forth, and the lower backrest part 4 side has a lower outer circumferential tooth at the shaft fixing part between the lower backrest part 4 and the seat sheet 2. 21, and a lower reversing Taumel mechanism 19 is provided on the seat 2 side having lower inner circumferential teeth 23,
A shaft stop between the upper backrest portion 5 and the lower backrest portion 4 includes:
An upper taumel mechanism 42 in which the upper backrest portion 5 side is the upper inner circumferential teeth 46 and the lower backrest portion 4 side is the upper outer circumferential teeth 44.
are provided, and the lower outer circumferential tooth 2 of the lower reversal Taumel mechanism 19 is provided.
1 and the upper inner tooth 46 of the upper Taumel mechanism 42, a rotation transmission member 58 is provided so that when the lower backrest 4 is rotated back and forth, the upper backrest 5 is rotated in the opposite direction. In the vehicle backrest configured to rotate back and forth in the direction, a fine adjustment device 60 is attached to the upper inner teeth 46 of the upper backrest portion 5 to directly rotate the upper inner teeth 46. A device for finely adjusting the inclination angle of the upper backrest of the seat.