JP3679248B2 - Seat back - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a backrest for a seat provided in a vehicle or the like, and more specifically, includes a lower backrest and an upper backrest disposed thereon, and further adjusts the inclination of the upper backrest relative to the lower backrest. The present invention relates to a seat back with a function of
[0002]
[Prior art]
Conventionally, in a vehicle seat used for, for example, a long-distance bus and a train, it is common to be able to adjust the angle of the entire backrest. This type is also known. In this type of seat, a lower backrest (lower backrest) located on the lower side is supported on the seat frame by the first shaft so as to be pivotable in the front-rear direction. A backrest (upper backrest) located on the upper side is supported on the lower backrest by the second shaft. And the mechanism for adjusting the inclination of the upper back with respect to a lower back is provided. According to this seat, the user can adjust the upper back to the desired inclination, which means that the user can lean more comfortably than the one that only adjusts the overall inclination of the back. is there.
[0003]
Various types of mechanisms for adjusting the inclination of the upper backrest have been proposed, and one of them is one that automatically operates the upper backrest. For example, a type in which the electric motor is directly connected to the second shaft by driving and a type in which the second shaft and the electric motor are connected by driving through a gear or the like are known. In any of the types described above, the electric motor is disposed in the vicinity of the second shaft. In a vehicle seat incorporating these mechanisms, the drive shaft of the electric motor rotates in response to a switch operation by the user, the rotation is transmitted to the second shaft, and the upper back rest uses the second shaft as a fulcrum. Rotate. The inclination of the upper back is adjusted by the operation amount of the switch, the operation time, and the like.
[0004]
[Problems to be solved by the invention]
However, in the type in which the second shaft is directly driven to rotate, a large output is required for the electric motor. In the type in which the rotation of the electric motor is indirectly transmitted to the second shaft via a gear or the like, the output of the electric motor can be increased to some extent by setting the gear ratio, but in a narrow space near the second shaft, the size is small. There is a limit to the arrangement of a large number of gears having greatly different (number of teeth), and as a result, it is difficult to greatly increase the output. Therefore, a large electric motor is required to reliably operate the upper backrest, which contributes to an increase in the size of the backrest, and hence the vehicle seat, weight increase, and price increase. In addition, since the electric motor is arranged in the vicinity of the second shaft, the installation location of the electric motor is limited, and there is a problem that the degree of design freedom including the arrangement of other parts is greatly restricted.
[0005]
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a seat back which can be adjusted to an arbitrary inclination by automatically operating the upper back even if the motor has a high degree of design freedom and a small output. That is.
[0006]
[Means for Solving the Problems]
In order to solve the above problems, the present invention has a lower backrest attached to a seat frame of a seat, an upper backrest supported by a shaft on the lower backrest, a movable portion, and the movable portion is It has a drive unit for reciprocating according to the switch operation and stopping at a predetermined position. In the drive unit, the motor mounted on the lower backrest and the force of the movable unit by the drive unit are expanded. And a transmission mechanism for rotating the upper backrest in the front-rear direction with the shaft as a fulcrum by transmitting to the upper backrest.
[0007]
According to the above configuration , when the user performs a switch operation, the movable part of the prime mover reciprocates according to the operation. The force of the movable part by the drive part is expanded by the transmission mechanism and transmitted to the upper backrest. The upper back supported by the lower back by the shaft rotates in the front-rear direction with the shaft as a fulcrum. By this rotation, the inclination of the upper back with respect to the lower back changes. As described above, the transmission mechanism exhibits the function of transmitting the reciprocating motion of the movable part located at a position away from the upper back to the upper back and the function of expanding the force of the movable part during the transmission. . The movable part stops at a predetermined position in response to the switch operation. In response to this stop, the operation of the upper back rest stops, and the upper back rest is maintained at a predetermined inclination.
[0008]
In addition to the above-described configuration, the present invention may be configured such that the transmission mechanism is rotatably supported by a shaft on the lower back rest and is connected to the movable portion at one end portion of the transmission mechanism. A second link connecting the other end of the first link and the upper backrest.
[0009]
According to the said structure, when the movable part of a motor | power_engine is reciprocated by a drive part, the movement will be transmitted to an upper back via a 1st link, a shaft, and a 2nd link. In the transmission path from the movable part to the upper backrest, the first link acts as a so-called “lever”. The force applied from the movable part to one end of the first link is enlarged {(distance from one end of the first link to the shaft) / (distance from the shaft to the other end of the first link)}. It is transmitted from the other end of the first link to the second link.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment in which the present invention is embodied in a backrest of a vehicle seat mounted on a long-distance bus will be described with reference to the drawings. As shown in FIG. 3, the seat 1 includes a base 3 fixed to a vehicle floor (not shown), a seat frame 4 attached to the base 3, and a cushion attached to the seat frame 4. A seat portion 5 and a backrest 6 supported on the rear portion (left side portion in FIG. 3) of the seat frame 4 are provided.
[0011]
As shown in FIGS. 1 and 3, the backrest 6 has a lower backrest 8 rotatably supported by a first shaft 7 at the rear portion of the seat frame 4 and an upper end portion of the lower backrest 8. An upper backrest 11 is rotatably supported by the second shaft 9. In order to adjust the inclination of the upper back rest 11 with respect to the lower back rest 8, a prime mover 12 is attached to the lower back rest 8. The prime mover 12 has a movable part 13 and a drive part 14 for reciprocating the movable part 13. A bracket 15 is fixed to the upper portion of the vertical frame 8a on the right side of the lower backrest 8, and the end portion of the drive portion 14 in an inclined state is supported by a pin 16. The drive unit 14 reciprocates the movable unit 13 substantially in the left-right direction in accordance with electric power supplied from an external power source (not shown). The driving unit 14 also has a function of stopping the movable unit 13 at an arbitrary position. The switch is operated by the user when adjusting the inclination of the upper backrest 11, and is provided at a place where the user's hand sitting on the seat 1 can reach, for example, an armrest (not shown). The switch is provided in a circuit that connects the external power source and the drive unit 14, and closes the circuit (including switching of the polarity of the voltage applied to the drive unit 14) or opens in accordance with the operation.
[0012]
The backrest 6 is a transmission mechanism for rotating the upper backrest 11 in the front-rear direction with the second shaft 9 as a fulcrum by enlarging and transmitting the force of the movable portion 13 by the drive portion 14 to the upper backrest 11. 17 is provided. The mechanism 17 will be described. A bracket 18 is fixed to an upper portion of the left vertical frame 8b of the lower backrest 8, and a first link 19 is rotatably supported by a pin 21 here. The lower end portion of the first link 19 is connected to the distal end portion of the movable portion 13 by a pin 22. A pin 23 is inserted into the upper end portion of the first link 19, and the lower end portion of the second link 24 is supported at the front end portion thereof. Here, in the first link 19, when the distance between the pins 21 and 22 is a and the distance between the pins 21 and 23 is b, in the present embodiment, the distances a and b are set so that the relationship of a> b is established. Each is set.
[0013]
The upper end portion of the second link 24 is connected to the lower left portion of the upper backrest 11 (near the upper portion of the second shaft 9) by a universal shaft joint (universal joint) 25. That is, the universal shaft joint 25 has two axes that do not coincide with each other and intersect at a certain angle, and is fastened to the upper backrest 11 on one shaft and fastened to the upper end portion of the second link 24 on the other shaft. Has been. The prime mover 12 and the transmission mechanism 17 are covered with covers 26 and 27 arranged in front and behind them.
[0014]
Next, the operation and effect of the present embodiment configured as described above will be described. 1 and 2 show a state in which the lower backrest 8 and the upper backrest 11 are linearized, that is, a state in which the upper and lower backrests 11 and 8 are not bent. In this state, many portions of the movable portion 13 protrude from the drive portion 14, and both the first link 19 and the second link 24 are greatly inclined. The user can lean against the backrest 6 in the same manner as a conventional backrest that does not bend.
[0015]
When the user performs a switch operation for changing the inclination of the upper backrest 11, the drive unit 14 is activated in accordance with the operation, and the movable unit 13 is moved to the drive unit 14 side as shown in FIGS. Retreat to. The movement of the movable portion 13 is transmitted to the lower left portion of the upper backrest 11 via the first link 19, the second link 24, and the universal shaft joint 25. In the course of this transmission, the first link 19 rotates counterclockwise in FIG. 4 with the pin 21 as a fulcrum. Along with this, a force is applied to the second link 24 so as to lower it, and the second link 24 moves downward while changing its inclination, so that the second link 24 becomes substantially vertical. The movement of the second link 24 is transmitted to the lower left portion of the upper backrest 11 via the universal shaft joint 25, and a downward force is applied to this portion. As a result, the upper backrest 11 tilts forward with the second shaft 9 as a fulcrum. That is, the backrest 6 bends with the second shaft 9 as a boundary.
[0016]
When the user performs a switch operation for returning the upper back rest 11 to the original state (the unbent state) from the above state, the prime mover 12 and the transmission mechanism 17 perform the operations opposite to those described above. . That is, the movable part 13 protrudes from the drive part 14, and the 1st link 19 rotates in the clockwise direction of FIG. Along with this, a force is applied to the second link 24 to push it up, and the second link 24 moves upward while changing the inclination, and enters an inclined state. An upward force is applied to the upper backrest 11, and the upper backrest 11 rotates backward with the second shaft 9 as a fulcrum.
[0017]
In addition, when the movable part 13 is stopped at an arbitrary position in accordance with a switch operation by the user, the operations of the first link 19, the second link 24, the universal shaft joint 25, etc. are stopped, and the upper back rest 11 is moved. The lower backrest 8 is kept at a predetermined inclination. Since the user can adjust the upper back support 11 to a desired inclination, the user can lean in a more comfortable posture than the one in which only the inclination of the entire back support is adjusted without bending. .
[0018]
By the way, in the transmission mechanism 17, the first link 19 functions as a so-called “lever”. The pin 22 corresponds to a force point, the pin 21 corresponds to a fulcrum, and the pin 23 corresponds to an action point. When the force applied to the force point (pin 22) by the movable portion 13 is F and the force applied to the action point (pin 23) is W, the force W is expressed by the following equation.
W = (a / b) · F
[0019]
As described above, the relationship of a> b is established in this embodiment. For this reason, the force F input to the first link 19 with the reciprocating motion of the movable portion 13 is multiplied by (a / b), and the expanded force W passes through the second link 24 and the universal shaft joint 25 and moves to the upper back. This is transmitted to 11. As described above, the transmission mechanism 17 exhibits the function of transmitting the reciprocating motion of the movable portion 13 to the upper backrest 11 and the function of expanding the force of the movable portion 13 during the transmission. In this embodiment, the prime mover 12 having a small output can be used as much as this force is increased. Unlike conventional technology, it is not necessary to use a large prime mover. As a result, it is possible to suppress the increase in the size, weight, and price of the backrest 6 and consequently the seat 1.
[0020]
Furthermore, in this embodiment, since the transmission mechanism 17 is interposed between the lower left portion of the upper backrest 11 and the prime mover 12, the movable portion 13 of the prime mover 12 is disposed at a location far from the second shaft 9. can do. In particular, since the prime mover 12 is disposed obliquely in the present embodiment, even the prime mover 12 in which the movable portion 13 reciprocates with a large stroke can be incorporated into the space in the lower backrest 8 without difficulty. . Furthermore, since the first link 19 and the second link 24 are arranged substantially in the vertical direction, the proportion of these in the width direction of the lower backrest 8 and the like is small. This is also effective in arranging the prime mover 12 having a large stroke. Thus, there are few restrictions received when the prime mover 12 is arranged in the space in the backrest 6, and the degree of freedom in design is higher than that of the conventional one.
[0021]
The present invention can be embodied in another embodiment described below.
[0022]
(1) The back cover of the present invention is suitable as a back cover for seats for vehicles such as passenger planes, passenger cars, passenger ships, etc. in addition to long-distance buses. You can also
[0023]
(2) The position of the movable part 13 may be detected by a sensor, and the operation of the movable part 13 may be controlled based on the detection result. For example, a limit switch that is turned on when the movable portion 13 moves forward (or rearward) from the front end position (or rear end position) of the appropriate stroke is provided, and when the switch is turned on, further advancement of the movable portion 13 ( Alternatively, the backward movement) may be stopped.
[0024]
(3) The mounting positions of the prime mover 12, the transmission mechanism 17, the universal shaft joint 25, and the like may be changed as appropriate. For example, the prime mover 12 and the transmission mechanism 17 may be attached to the lower backrest 8, and the universal shaft joint 25 may be attached to the upper backrest 11.
[0025]
【The invention's effect】
As described above, according to the present invention, even with a prime mover having a high degree of design freedom and a small output, the upper backrest can be automatically operated and adjusted to an arbitrary inclination.
[0026]
In addition , with a simple configuration, the force of the movable part can be reliably expanded and transmitted to the upper backrest.
[Brief description of the drawings]
FIG. 1 is a partial front view showing an internal structure of a backrest in an embodiment embodying the present invention.
FIG. 2 is an enlarged cross-sectional view taken along the line AA in FIG.
FIG. 3 is a schematic side view of a seat.
FIG. 4 is a partial front view showing the internal structure of the backrest when the upper backrest is tilted.
FIG. 5 is an enlarged cross-sectional view taken along line BB in FIG.
[Explanation of symbols]
1 seat 4 seat frame 6 backrest 8 lower backrest 9 second shaft 11 upper backrest 12 prime mover 13 movable portion 14 drive portion 17 transmission mechanism 19 first link 21 pin 24 as a shaft second link

Claims (2)

With a lower backrest mounted on the seat frame of the seat,
An upper back supported by a shaft on the lower back;
A prime mover having a movable part, a drive part for reciprocating the movable part according to a switch operation, and stopping at a predetermined position, and attached to the lower backrest in the drive part;
A transmission mechanism for rotating the upper backrest in the front-rear direction with the shaft as a fulcrum by enlarging and transmitting the force of the movable portion by the driving portion to the upper backrest ;
The transmission mechanism is
A first link that is pivotally supported about an axis in the front-rear direction and is connected to the movable part at one end of the lower back support by an axis;
A second link connecting the other end of the first link and the upper back;
It is equipped with
In the first link, an interval between the connecting portion of the movable part and the rotation center is set larger than an interval between the connecting portion of the second link and the rotation center.
Seto of the seat which is characterized a call. The seat back according to claim 1, wherein the second link and the upper back are connected by a universal shaft joint .

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