Vehicle seats

Abstract

This reduces discomfort felt by passengers when the seatback is tilted backward. [Solution] A vehicle seat (100) comprising a seat cushion (11), a seat back (12), a reclining mechanism, a lumbar support mechanism (40), and a control unit, in which the control unit pushes a support surface (12S) forward of the seat using the lumbar support mechanism (40) when the seat back (12) is tilted backward by more than a predetermined angle.

Description

[Technical Field]

[0001] The present disclosure relates to a structure of a vehicle seat equipped with a reclining mechanism. [Background technology]

[0002] 2. Description of the Related Art Vehicle seats are used that prevent the occupant's head from shifting position relative to the headrest and prevent the occupant's clothing from being rolled up when the seat back is tilted backward.

[0003] For example, Patent Document 1 discloses a vehicle seat that includes a connecting link that rotatably connects the lower part of the seat back to the rear end of the seat cushion, and a parallel link that connects the seat cushion to the floor, and in which the rear end of the seat cushion is displaced upward and rearward when the seat back is tilted backward.

[0004] Furthermore, Patent Document 2 discloses a vehicle seat in which the seat back and seat cushion are connected by a link mechanism including an L-shaped link, and when the seat back is tilted backward, the seat cushion moves upward and forward.

[0005] Patent document 3 also discloses a vehicle seat having a top plate drive unit that reduces the step between the top plate and the seat back by moving the top plate, which supports the buttocks of the seat occupant on the seat cushion, forward and upward when the seat back is tilted backward. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-160217 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-246599 [Patent Document 3] Japanese Patent Publication No. 2023-004166 Summary of the Invention [Problem to be solved by the invention]

[0007] The conventional vehicle seat described in Patent Document 1 and elsewhere allows the rotation center of the occupant's back to be closer to the rotation center of the seatback. However, because the rotation center of the seatback is away from the boundary between the seatback and the seat cushion, when the seatback is tilted backward, a step is created between the rear end of the seat cushion and the bottom end of the seatback, causing the bottom end of the seatback to lower. This can cause discomfort to the occupant due to the step, pressure on the abdomen due to the rear of the buttocks dropping into the step, or fatigue or discomfort due to uneven pressure distribution on the back.

[0008] Therefore, an object of the present disclosure is to reduce discomfort felt by occupants when the seat back is tilted backward. [Means for solving the problem]

[0009] The vehicle seat of the present disclosure is a vehicle seat comprising a seat cushion frame that supports a seat cushion, a seat back frame that supports a seat back, a reclining mechanism that tilts the seat back backward by a curved bracket integral with the seat back frame moving in an arc relative to the seat cushion frame, a lumbar support mechanism that pushes the support surface of the seat back forward of the seat, and a control unit that adjusts the operation of the lumbar support mechanism, wherein the control unit is characterized in that when the seat back is tilted backward by more than a predetermined angle, the control unit pushes the support surface forward of the seat using the lumbar support mechanism.

[0010] As a result, when the seatback is tilted backward, the lumbar support mechanism reduces the step that occurs between the rear end of the seat cushion and the lower end of the seatback, thereby reducing discomfort to the occupant.

[0011] In the vehicle seat of the present disclosure, the control unit may adjust the position of the support surface in the front-rear direction in accordance with the tilt angle of the seat back.

[0012] The difference in height between the rear end of the seat cushion and the bottom end of the seatback varies depending on the angle of inclination of the seatback. Therefore, by adjusting the front-rear position of the support surface according to the angle of inclination of the seatback, it is possible to reduce discomfort felt by the occupant regardless of the angle of inclination of the seatback.

[0013] In the vehicle seat of the present disclosure, the reclining mechanism may include a curved rail attached to the seat cushion frame, and the bracket may move while being guided by the curved rail, thereby causing the bracket to rotate relative to the seat cushion frame.

[0014] This allows the center of rotation to be located close to the occupant's hip point while the reclining mechanism is located away from the center of rotation, thereby preventing the occupant sitting in the vehicle seat from coming into contact with the reclining mechanism.

[0015] In the vehicle seat of the present disclosure, the curved rail may have a curved shape with a varying radius of curvature.

[0016] This allows multiple rotation centers of the seat back to be set, allowing for highly flexible reclining movements. [Effects of the Invention]

[0017] The present disclosure can reduce discomfort felt by occupants when the seat back is tilted backward. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a system diagram showing the structure of a vehicle seat according to an embodiment; [Figure 2] 2 is an elevational view showing a state in which an occupant is seated in the vehicle seat shown in FIG. 1. FIG. [Figure 3] 2 is an explanatory diagram showing the operation of each part when the seat back of the vehicle seat shown in FIG. 1 is tilted backward. [Figure 4]2 is an elevational view showing a state in which a passenger is seated in the vehicle seat shown in FIG. 1 and the seat back is tilted backward. FIG. [Figure 5] FIG. 10 is an elevation view showing a comparative example of a vehicle seat with an occupant seated and the seat back tilted backward. DETAILED DESCRIPTION OF THE INVENTION

[0019] A vehicle seat 100 according to an embodiment will be described below with reference to the drawings. Note that FR, UP, and RH shown in each drawing indicate the front, upper, and right sides of the vehicle seat 100, respectively. The opposite directions of FR, UP, and RH indicate the rear, lower, and left sides. Hereinafter, when the terms front-rear, left-right, and up-down are used in the description, they refer to the front-rear direction of the vehicle seat 100, the left-right direction, and the up-down direction, unless otherwise specified.

[0020] As shown in FIG. 1, the vehicle seat 100 includes a seat cushion 11, a seat back 12, a seat cushion frame 13, a seat back frame 14, a reclining mechanism 20, a lumbar support mechanism 40, and a control unit 50.

[0021] The seat cushion frames 13 are metal plate-shaped members arranged at the left and right ends of the vehicle seat 100 and extending in the front-to-rear direction. The left and right seat cushion frames 13 are connected to each other by a plurality of cross members (not shown) and are attached to the vehicle body floor (not shown) by front and rear legs 15, 16. The seat cushion 11 is attached on top of the left and right seat cushion frames 13. The seat cushion 11 has a seat surface 11S that supports the buttocks 61 (see FIG. 2) of a seated occupant 60.

[0022] The seatback frame 14 is a metal plate-like member that is disposed above and behind the left and right seat cushion frames 13 and extends in the vertical direction. The left and right seatback frames 14 are connected in the horizontal direction by connecting members (not shown). The left and right seatback frames 14 are connected to the left and right seat cushion frames 13 by reclining mechanisms 20. A seatback 12 is attached in front of the left and right seatback frames 14. The seatback 12 has a support surface 12S that supports the back 62 (see FIG. 2) of a seated occupant 60.

[0023] The reclining mechanism 20 includes a curved rail 21, a slider 22, a bracket 23, a rod 31, a worm gear case 32, a screw 33, and a motor 35. The reclining mechanism 20 tilts the seat back 12 backward around a rotation center C. Here, the rotation center C is located at a position away from the reclining mechanism 20 and close to a hip point 65 (see FIG. 4), which is the center of rotation of the upper body of the occupant 60 when the seat back 12 tilts backward.

[0024] The curved rail 21 is an arc-shaped rail with a radius R attached to the side surface of the seat cushion frame 13 with a bolt 24. The slider 22 is guided by the curved rail 21 and is movable along the curved rail 21. The bracket 23 is a curved plate-like member with a lower portion curved in an arc and an upper portion extending upward. The upper portion of the bracket 23 is fixed to the side surface of the lower portion of the seat back frame 14 with a bolt 26. This makes the bracket 23 and the seat back frame 14 integral. The lower portion of the bracket 23 is fixed to the slider 22 with a bolt 25. Therefore, when the slider 22 moves in an arc while being guided by the curved rail 21, the lower portion of the bracket 23 rotates relative to the seat cushion frame 13, and the seat back frame 14 rotates around a rotation center C. This causes the seat back 12 to tilt backward. Here, the rotation center C is the center of curvature of the curved rail 21.

[0025] The rod 31 is a round bar member supported by the left and right seat cushion frames 13 and extending in the left-right direction. The left and right ends of the rod 31 penetrate the left and right seat cushion frames 13 and extend to the outside of the left and right seat cushion frames 13. The worm gear case 32 houses worm gears connected to both ends of the rod 31 and a screw 33. The worm gears engage with the screw 33 inside the worm gear case 32. The worm gear case 32 is attached to the outside of the seat cushion frame 13 so as to be rotatable around the rod 31. The rear end of the screw 33 is rotatably connected to the lower part of the bracket 23 by a fastening portion 34. The motor 35 is disposed between the left and right seat cushion frames 13 and drives the rod 31 to rotate. The motor 35 also detects and outputs the rotational angle position of the rod 31.

[0026] The lumbar support mechanism 40 is disposed inside the seat back 12 and pushes the support surface 12S of the seat back 12 forward of the seat.

[0027] The control unit 50 is a computer that includes a CPU 51, which is an internal processor that processes information, and a memory 52 that stores programs and control data. The control unit 50 is connected to the motor 35, the lumbar support mechanism 40, and a reclining switch 53. The control unit 50 receives as input the rotation angle of the rod 31 detected by the motor 35 and an operation signal of the reclining switch 53. The control unit 50 adjusts the operation of the motor 35 and the lumbar support mechanism 40 based on the input signals.

[0028] 2, when the seat back 12 is in an upright position, the back 62 of the occupant 60 and the back surface 41 of the lumbar support mechanism 40 are substantially parallel to each other. The amount of depression of the support surface 12S of the seat back 12 is substantially constant along the surface of the back 62, and the pressure applied from the support surface 12S to the back 62 is also substantially constant. This state is comfortable for the occupant 60.

[0029] Next, the operation of the seat back 12 of the vehicle seat 100 shown in Figures 1 and 2 when tilting backward will be described with reference to Figures 3 and 4. The operation of the CPU 51 of the control unit 50 is realized by the CPU 51 executing a program stored in the memory 52.

[0030] When the occupant 60 operates the reclining switch 53 and an operation signal of the reclining switch 53 is input to the control unit 50 , the CPU 51 activates the motor 35 of the reclining mechanism 20 .

[0031] When the motor 35 rotates the rod 31, the worm gears connected to both ends of the rod 31 rotate, as shown by arrow 90 in FIG. 3. As a result, the screw 33 engaged with the worm gear moves forward relative to the seat cushion frame 13, as shown by arrow 91 in FIG. 3. Accordingly, the fastening portion 34 at the rear end of the screw 33 moves forward. When the fastening portion 34 moves forward, the slider 22 moves in an arc along the curved rail 21, as shown by arrow 92 in FIG. 3. As a result, the seat back 12 rotates around the rotation center C and tilts backward, as shown by arrow 93 in FIG. 3.

[0032] 3, when the seat back 12 tilts backward, the lower end 12D of the seat back 12 rotates to enter behind the rear end 11A of the seat cushion 11. Therefore, when the seat back 12 tilts backward, the lower end 12D of the seat back 12 becomes lower than the rear end 11A of the seat cushion 11, and a step G occurs between the lower end 12D and the rear end 11A.

[0033] When the seat back 12 starts to tilt backward, the CPU 51 calculates the tilt angle of the seat back 12 based on the rotation angle position of the rod 31 input from the motor 35. Then, when the tilt angle of the seat back 12 reaches or exceeds a predetermined angle, the CPU 51 activates the lumbar support mechanism 40 as shown in FIG. 4. The predetermined angle can be set freely, for example, between 30° and 60°. As a result, the surface 41 is pushed forward in the seat, as indicated by the outline arrow 98 in FIG. 4, and the support surface 12S of the seat back 12 is pushed forward in the seat. Note that hatching in FIG. 4 indicates a state in which the surface 41 of the lumbar support mechanism 40 has moved forward. As a result, the step G (see FIG. 5) between the lower end 12D of the seat back 12 and the rear end 11A of the seat cushion 11 is reduced to the step H (see FIG. 4). This prevents the rear of the buttocks 61 of the occupant 60 from entering the step G, thereby preventing the occupant 60 from feeling pressure in the abdomen.

[0034] Furthermore, operation of the lumbar support mechanism 40 pushes the surface 41 toward the front of the seat, so that the back 62 of the occupant 60 of the seat back 12 and the surface 41 become substantially parallel, as shown in part A in Figure 4. Therefore, just as when the seat back 12 is in an upright position, the amount of sinking of the support surface 12S of the seat back 12 is substantially constant along the surface of the back 62, and the pressure applied from the support surface 12S to the back 62 is also substantially constant, resulting in a comfortable state for the occupant 60. This makes it possible to prevent the occupant 60 from feeling fatigue or discomfort due to uneven pressure distribution on the back 62.

[0035] Next, referring to Figure 5, a case where the seat back 12 is tilted backward while an occupant 60 is seated in a comparative vehicle seat 110 will be described. Here, in the comparative vehicle seat 110, the control unit 50 does not operate the lumbar support mechanism 40 even when the seat back 12 is tilted backward. Other configurations are the same as those of the vehicle seat 100.

[0036] As shown in FIG. 5, in a vehicle seat 110, when an occupant 60 operates the reclining switch 53 and the seatback 12 tilts backward, as previously described with reference to FIG. 4, the lower end 12D of the seatback 12 becomes lower than the rear end 11A of the seat cushion 11, creating a step G between the lower end 12D and the rear end 11A (see part B in FIG. 5). As a result, the rear of the occupant's buttocks 61 enters the step G, and the occupant's abdomen may bend, causing a feeling of pressure. In addition, the back 62 of the occupant 60 and the back-side surface 41 of the lumbar support mechanism 40 are no longer substantially parallel, and the amount of sinking of the support surface 12S of the seatback 12 is no longer substantially constant along the surface of the back 62. As a result, the occupant 60 may feel fatigue or discomfort due to the uneven pressure distribution on the back 62.

[0037] In contrast, in the vehicle seat 100 of the embodiment, when the tilt angle of the seat back 12 becomes equal to or greater than a predetermined angle, the lumbar support mechanism 40 pushes the support surface 12S toward the front of the seat, thereby reducing the step G (see Figure 5) that occurs between the lower end 12D of the seat back 12 and the rear end 11A of the seat cushion 11 to step H (see Figure 4), thereby suppressing the discomfort felt by the occupant 60 as described above.

[0038] Furthermore, the vehicle seat 100 can position the rotation center C close to the hip point 65 of the occupant 60, while disposing the reclining mechanism 20 at a position away from the rotation center C. This makes it possible to prevent the occupant 60 seated in the vehicle seat 100 from coming into contact with the reclining mechanism 20.

[0039] In the above description, the CPU 51 of the control unit 50 has been described as causing the lumbar support mechanism 40 to push the support surface 12S forward of the seat when the tilt angle of the seat back 12 is equal to or greater than a predetermined angle, but this is not limiting. The CPU 51 of the control unit 50 may adjust the rearward position of the support surface 12S according to the tilt angle of the seat back 12. For example, the amount of pushing of the support surface 12S forward of the seat may increase as the tilt angle of the seat back 12 increases.

[0040] The step G that occurs between the lower end 12D of the seat back 12 and the rear end 11A of the seat cushion 11 changes depending on the tilt angle of the seat back 12. Therefore, by adjusting the front-rear direction position of the support surface 12S according to the tilt angle of the seat back 12, the discomfort felt by the occupant 60 can be reduced regardless of the tilt angle of the seat back 12.

[0041] In the above description, the curved rail 21 is described as an arc-shaped rail, but is not limited to this. For example, the curved rail 21 may have a curved shape with multiple radii of curvature. In this case, the curved rail 21 has multiple centers of curvature, and multiple rotation centers C of the seat back 12 can be set. This allows for a highly flexible reclining operation.

[0042] In addition, in the above description, the bracket 23 is fixed to the seat back frame 14 by the bolt 26, but this is not limitative as long as it is provided integrally with the seat back frame 14. For example, a seat back frame assembly in which the seat back frame 14 and the bracket 23 are molded integrally may be used. [Explanation of symbols]

[0043] 11 seat cushion, 11A rear end, 11S seat surface, 12 seat back, 12D lower end, 12S support surface, 13 seat cushion frame, 14 seat back frame, 15, 16 legs, 20 reclining mechanism, 21 curved rail, 22 slider, 23 bracket, 24, 25, 26 bolt, 31 rod, 32 worm gear case, 33 screw, 34 fastening portion, 35 motor, 40 lumbar support mechanism, 41 surface, 50 control unit, 51 CPU, 52 memory, 53 reclining switch, 60 occupant, 61 buttocks, 62 back, 65 hip point, 100, 110 vehicle seat, C rotation center, G, H step.

Claims

1. a seat cushion frame that supports the seat cushion; a seat back frame supporting the seat back; a reclining mechanism in which a curved bracket integrally provided with the seat back frame moves in an arc relative to the seat cushion frame, thereby tilting the seat back backward; a lumbar support mechanism that pushes the support surface of the seat back forward; A control unit that adjusts the operation of the lumbar support mechanism, the control unit causes the lumbar support mechanism to push the support surface forward of the seat when the seat back is tilted backward by a predetermined angle or more; A vehicle seat characterized by:

2. 2. The vehicle seat according to claim 1, the control unit adjusts the position of the support surface in the front-rear direction in accordance with the tilt angle of the seat back; A vehicle seat characterized by:

3. 3. The vehicle seat according to claim 1 or 2, The reclining mechanism includes: A curved rail attached to the seat cushion frame, the bracket is guided by the curved rail to move, thereby rotating with respect to the seat cushion frame; A vehicle seat characterized by:

4. The vehicle seat according to claim 3, the curved rail has a curved shape with a varying radius of curvature; A vehicle seat characterized by:

Images