JP7803161B2 - Vehicle seat back - Google Patents

Description

The technology disclosed herein relates to a vehicle seat back.

Patent Document 1 describes a vehicle seat back. The seat back includes a seat back frame, a cushion pad, and a pressure-receiving member. The pressure-receiving member is a resin plate. The pressure-receiving member is located behind the cushion pad and attached to the seat back frame via a wire. The wire is molded integrally with the pressure-receiving member by insert molding. The pressure-receiving member receives a load from the back of the occupant. Furthermore, when an impact load from the occupant's back is input to the pressure-receiving member during a rear-end collision of the vehicle, the pressure-receiving member is pushed by the occupant's back and moves rearward along with the occupant. The displacement of the pressure-receiving member reduces the impact load acting on the occupant's neck during a collision.

Patent Document 2 also describes a vehicle seat back equipped with a plate-shaped pressure-receiving member. The pressure-receiving member can be swung by an actuator. When a turning sensor detects that the vehicle is turning, the actuator swung the pressure-receiving member in accordance with the turning direction. The swung pressure-receiving member can tilt the driver's posture inward relative to the turning direction.

Japanese Patent Application Laid-Open No. 2019-182273 JP 2013-49356 A

When a vehicle turns, the posture of the occupant seated in the seat tends to change. Vehicle seats are required to suppress changes in the occupant's posture. However, if the vehicle seat holds the occupant's posture too firmly, it will make the ride uncomfortable when the vehicle is traveling straight. Furthermore, holding the occupant's posture too firmly will increase the reaction force from the seat back in response to changes in the occupant's posture when turning, making the occupant feel uncomfortable.

Unfortunately, the conventional vehicle seat described in Patent Document 1 cannot solve this problem. Furthermore, the conventional vehicle seat described in Patent Document 2 is very complicated because it requires electrical devices such as actuators and sensors.

The technology disclosed here reduces changes in occupant posture when cornering without compromising ride comfort.

The technology disclosed herein relates to a vehicle seat back.
A pad that supports the back of the occupant,
a pressure-receiving member located behind the pad and receiving a load from the back of the occupant via the pad,
The pad includes an elastically deformable foam member and a reinforcing member attached to a rear surface of the foam member and reinforcing the foam member,
The pressure-receiving member has a base portion located at a center portion in a width direction of the seat back, and a plurality of side pieces extending outward in the width direction from both sides of the base portion,
The pad has a reinforcement reducing portion that reduces the reinforcement of the reinforcing member at a position that overlaps with a part of the side piece when viewed in a direction perpendicular to the surface of the seat back.

With this configuration, the base of the pressure-receiving member is located in the center in the width direction and supports the center of the occupant's back. The side pieces of the pressure-receiving member are located on either side of the base and support either side of the occupant's back.

When the vehicle is traveling straight, the pressure-receiving member receives the load from the entire back of the occupant via the pad. The pad has a foam member and a reinforcing member. The load from the occupant's back is received primarily by the base of the pressure-receiving member, as the foam member reinforced by the reinforcing member undergoes compressive deformation. The pad and pressure-receiving member receive the load from the occupant's back over their entire wide surface. Therefore, when the vehicle is traveling straight, the seat back can firmly support the occupant's back without compromising ride comfort.

When a vehicle turns, the occupant's posture tends to change in a direction that causes the thorax to rotate around the spine and/or tilt left or right. As the occupant's posture changes, a load is input locally from the sides of the occupant's back to the seat back.

Here, occupants include both the driver sitting in the driver's seat and holding the steering wheel, and the passenger sitting in the front passenger seat. The changes in the driver's posture when the vehicle turns may not coincide with the changes in the passenger's posture when the vehicle turns.

The pad has a reinforcement depression. The reinforcement depression is located in a position that overlaps with a portion of the side piece. Localized loads from the sides of the occupant's back are input to the pad at the position of the reinforcement depression.

The reinforcement reduction section reduces the reinforcement of the reinforcing member. When a local load is initially applied, the foam member undergoes significant compressive deformation at the reinforcement reduction section. This prevents a strong reaction force from acting on the occupant when a local load is initially applied.

After the foam member is compressed and deformed, the local load from the side of the occupant's back is received primarily by the side pieces of the pressure-receiving member. A reaction force is then applied from the pressure-receiving member to the side of the occupant's back through the pad. This suppresses changes in the occupant's posture.

A seat back with the above configuration can firmly support the occupant's back and suppress changes in posture when the vehicle turns, while suppressing strong reaction forces on the occupant.

On the other hand, the reinforcing lowering portion is provided partially at a specific location on the pad. When a load is input to the seat back from the entire back of the occupant, such as when the vehicle is traveling straight, the reinforcing lowering portion does not substantially function. A seat back configured as described above does not deteriorate the ride comfort when the vehicle is traveling straight.

As a result, a seat back with the above configuration can suppress changes in the occupant's posture when turning without compromising ride comfort when traveling straight or turning.

The reinforcing lowered portions may be located on both sides of the center line of the seat back in the width direction.

The reinforcement lowering sections are located on both the right and left sides of the occupant's back. The seat back can suppress changes in the occupant's posture when turning right or left.

The side pieces are arranged at intervals in the up-down direction on both sides of the base,
The reinforcing lowered portion overlaps with the specific side piece on each side of the base portion,
The particular side piece may have higher rigidity than the side piece adjacent to the particular side piece.

The highly rigid specific side pieces can apply sufficient reaction force to the sides of the occupant's back. As a result, the seat back can suppress changes in the occupant's posture when the vehicle turns.

The reinforcement lowering portion may be located behind the occupant's thorax.

When a vehicle turns, the thorax tends to rotate around the spine and/or tilt left or right. By positioning the reinforcement lowering portion behind the occupant's thorax, the side pieces of the pressure-receiving member can apply a reaction force to the thorax, which tends to displace. The seat back can effectively suppress changes in the occupant's posture when the vehicle turns.

The side pieces may extend forward and outward in the width direction from the base.

The side pieces extending diagonally forward from the base can apply a reaction force to the areas from the sides of the occupant's back to the sides of the occupant's body. The seat back can effectively prevent the occupant's posture from changing in the direction that causes the thorax to rotate and/or tilt left or right.

the reinforcing member is a nonwoven fabric,
The reinforcement reduced portion may be a notch or a slit formed in the nonwoven fabric.

The nonwoven fabric attached to the rear surface of the foam member controls the amount of compression of the foam member, allowing the seat back to properly support the occupant's back and improve riding comfort. The notches or slits formed in the nonwoven fabric do not restrict the rear surface of the foam member, reducing the reaction force when a load is input from the occupant's back. As a result, the seat back initially reduces the reaction force on the occupant's back in response to localized load input when the vehicle turns, and then, mainly through the side pieces of the pressure-receiving member, applies sufficient reaction force to the sides of the occupant's back, suppressing changes in the occupant's posture.

The vehicle seat back may further include an airbag for seat ventilation positioned between the pad and the pressure-receiving member.

The airbag prevents direct contact between the pad and the pressure-receiving member, including at the reinforcement lowered portion. This reduces wear and/or damage to the foam member.

As described above, the vehicle seat back can suppress changes in the occupant's posture when turning without compromising ride comfort.

FIG. 1 shows a vehicle seat. FIG. 2 shows the interior of the seat back as seen from the front. FIG. 3 shows the inside of the seat back as seen from the side. FIG. 4 shows the interior of the seat back as seen from the rear. FIG. 5 shows the pressure-receiving member as seen from the front. The left diagram in FIG. 6 shows the pressure-receiving member as seen from the side, and the right diagram shows the pressure-receiving member as seen from the rear. FIG. 7 shows the VII-VII end face of FIG. FIG. 8 shows the rear surface of the pad. FIG. 9 shows a modified rear surface of the pad.

Embodiments of vehicle seat backs will be described below with reference to the drawings. The seat backs described here are examples.

(Overall seatback structure)
The vehicle seat 1 is installed in the vehicle cabin as a front seat. In the following description, the front, rear, left, right, and top and bottom of the vehicle seat 1 correspond to the front, rear, left, right, and top and bottom of the vehicle when the vehicle seat 1 is installed in the vehicle cabin. The left-right direction corresponds to the width direction of the vehicle seat.

As shown in Figure 1, the vehicle seat 1 includes a seat back 11, a seat cushion 12, and a headrest 13. The seat back 11 supports the back of the occupant 9 (see also Figure 3). The seat cushion 12 supports the buttocks of the occupant 9. The headrest 13 supports the head of the occupant 9.

As shown in Figures 2 to 4 and 6, the seat back 11 has a frame 2, a pad 3, a cover 30, and a pressure-receiving member 4.

The frame 2 has left and right side frames 21, an upper frame 22, and a lower frame 23. The upper frame 22 connects the upper ends of the left and right side frames 21 in the left-right direction. The lower frame 23 connects the lower ends of the left and right side frames 21 in the left-right direction. When viewed from the front, the frame 2 is a roughly rectangular frame.

The pad 3 is located in front of the frame 2. As shown in the left diagram of Figure 6, the pad 3 is composed of a foam member 31 and a reinforcing member 32 attached to the rear surface of the foam member 31. The foam member 31 is a cushion member made of, for example, urethane foam. The reinforcing member 32 is made of, for example, nonwoven fabric. The reinforcing member 32 reinforces the rear surface of the foam member 31. The foam member 31 reinforced by the reinforcing member 32 elastically deforms when subjected to a load from the back of the occupant 9, and applies an appropriate reaction force to the back of the occupant 9.

The cover 30 is roughly bag-shaped and covers the entire seat back 11. As described below, the vehicle seat 1 is equipped with seat ventilation 5. The cover 30 is made of a breathable material, such as fabric, or natural or synthetic leather with numerous small holes.

The pressure-receiving member 4 is located inside the frame 2, behind the pad 3. The pressure-receiving member 4 receives the load from the back of the occupant 9 via the pad 3. Details of the pressure-receiving member 4 will be described later.

As shown in the left diagram of Figure 6, an airbag 51 of the seat ventilation 5 is positioned between the pad 3 and the pressure-receiving member 4. The airbag 51 prevents the rear surface of the pad 3 from coming into direct contact with the pressure-receiving member 4. The airbag 51 reduces wear and/or damage to the pad 3.

The seat ventilation 5 draws air from the interior of the vehicle, conditioned by the air conditioning system, into the seat back 11 through the surface of the seat back 11. The seat ventilation 5 has an airbag 51 and a fan 52.

As shown in the left diagram of Figure 6 or Figure 8, the foam member 31 has multiple through-holes 311. Each through-hole 311 penetrates the foam member 31 from the front surface to the rear surface. As mentioned above, the skin 30 is made of a breathable material.

As shown in Figures 2 to 4, the fan 52 is located inside the frame 2, above the pressure-receiving member 4. The fan 52 has an intake port 521 on its front surface. The fan 52 has an exhaust port 522 on each of its left and right sides. The two exhaust ports 522 open into the interior of the seat back 11.

The suction port 521 is connected to the rear surface of the airbag 51. Although not shown in detail in the figure, openings connected to each of the through holes 311 in the foam member 31 are formed on the front surface of the airbag 51.

When the fan 52 is activated, air from within the vehicle cabin is drawn into the airbag 51 through the skin 30 and the through-holes 311. The airbag 51 functions as a manifold that collects the air drawn in through each of the through-holes 311. The fan 52 draws air from within the airbag 51 through the intake port 521 and expels it from the exhaust port 522.

(Structure of pressure-receiving member)
The pressure-receiving member 4 has a main body 6 and a rigid member 7 .

The main body 6 has a base 69 and multiple side pieces 60. The main body 6 is plate-shaped and thin in the front-to-rear direction, and is made of, for example, synthetic resin.

The base 69 is located in the center of the width of the seat back 11. When viewed from the front, the base 69 is roughly rectangular and extends in the vertical and horizontal directions. The base 69 has multiple holes formed in it to reduce its weight.

The upper end of the base 69 is located at a position corresponding to the lower part of the thorax 91 of the occupant 9 (see also Figure 5). The lower end of the base 69 is located at a position corresponding to the waist of the occupant 9. The base 69 supports the center of the back of the occupant 9 in the left-right direction, between the position corresponding to the lower part of the thorax 91 of the occupant 9 and the position corresponding to the waist. The thorax 91 includes the clavicle, sternum, ribs, and thoracic vertebrae of the human body.

The side pieces 60 extend outward in the width direction from both left and right side edges of the base 69. More specifically, when viewed from the front, the side pieces 60 extend outward in the width direction from the side edges of the base 69 (see the right diagram in Figure 5 or Figure 6), and when viewed from the side, they extend further forward than the base 69 (see the left diagram in Figure 6). The side pieces 60 are inclined forward relative to the base 69.

The multiple side pieces 60 are arranged vertically at intervals. From top to bottom, the main body 6 has a first side piece 61, a second side piece 62, a third side piece 63, a fourth side piece 64, a fifth side piece 65, a sixth side piece 66, and a seventh side piece 67. Note that each of the first side piece 61 to the seventh side piece 67 has the same shape on both the left and right sides.

The first side piece 61 is located at the upper end of the base 69. The first side piece 61 has the shortest length in the left-right direction. The first side piece 61 has higher rigidity than the adjacent second side piece 62. The first side piece 61 is formed with a first hole 611 for weight reduction and/or rigidity adjustment.

The second side piece 62 is located below the first side piece 61. The second side piece 62 to the seventh side piece 67 are all approximately the same length. Two second holes 621 are formed in the second side piece 62 for weight reduction and/or rigidity adjustment.

The third side piece 63 is located below the second side piece 62. A third hole 631 is formed in the third side piece 63 for weight reduction and/or rigidity adjustment.

The fourth side piece 64 is located below the third side piece 63. A first recess 641 is formed in the fourth side piece 64 to improve rigidity. The first recess 614 is recessed from the front to the rear of the fourth side piece 64 (see the left diagram in Figure 6). A protrusion is formed on the rear surface of the fourth side piece 64.

The fifth side piece 65 is located below the fourth side piece 64. Like the fourth side piece 64, the fifth side piece 65 also has a second recess 651 formed therein to improve rigidity.

The sixth side piece 66 is located below the fifth side piece 65. Like the fourth side piece 64, the sixth side piece 66 also has a third recess 661 formed therein to improve rigidity. The seventh side piece 67 is located below the sixth side piece 66. Like the fourth side piece 64, the seventh side piece 67 also has a fourth recess 671 formed therein to improve rigidity. The tip of the sixth side piece 66 and the tip of the seventh side piece 67 are connected to each other in the vertical direction.

The rigid member 7 is located on the rear side of the main body 6. The rigid member 7 is fixed to the rear surface of the main body 6. More specifically, a fixing portion 68 that bulges upward from a base 69 is formed at the upper end of the main body 6. The fixing portion 68 is located above the first side piece 61. The main body 6 has two fixing portions 68. The two fixing portions 68 are located at the center of the main body 6 in the left-right direction, spaced apart in the left-right direction. The rigid member 7 is fixed to the rear surface of each of the two fixing portions 68.

The rigid member 7 is made of, for example, synthetic resin. The rigid member 7 is thicker in the front-to-rear direction than the plate-shaped main body 6 (see also Figure 7). Furthermore, a metal rod 71 is embedded in each side of the rigid member 7. The metal rod 71 extends horizontally from the center of the rigid member 7 outward on both the left and right sides. The rigid member 7 has higher rigidity against load input in the front-to-rear direction than the main body 6. Furthermore, no metal rod is embedded in the center of the rigid member 7. The center of the rigid member 7 has relatively low rigidity, while the side portions have relatively high rigidity.

The rigid member 7 extends in the left-right direction near the upper end of the main body 6. When viewed from the front, the rigid member 7 overlaps with the fixing portion 68 and the first side piece 61 of the main body 6. The rigid member 7 is fixed to the main body 6 at its central portion, which has relatively low rigidity. The rigid member 7 extends outward on both the left and right sides beyond the tip of the first side piece 61.

The frame 2 supports the pressure-receiving member 4. The connecting member 8 connects the frame 2 and the pressure-receiving member 4.

The connecting member 8 includes an upper connecting member 81 and a lower connecting member 82. The upper connecting member 81 connects the rigid member 7 to the frame 2. The lower connecting member 82 connects the lower end of the main body 6 to the frame 2.

The upper connecting member 81 includes a first upper connecting member 811 on the right side and a second upper connecting member 812 on the left side. The first upper connecting member 811 and the second upper connecting member 812 have bilaterally symmetrical shapes with respect to the center line of the seat back 11. Below, the structure of the first upper connecting member 811 will be described in detail, and the description of the structure of the second upper connecting member 812 will be omitted where appropriate.

The first upper connecting member 811 connects the rigid member 7 to the right portion of the upper frame 22. The connection position between the first upper connecting member 811 and the rigid member 7 is the right portion of the center of the rigid member 7. More specifically, the connection position between the first upper connecting member 811 and the rigid member 7 is further outboard in the left-right direction than the fixed position between the rigid member 7 and the main body 6 (see the right diagram in Figure 5 or Figure 6). As shown in Figure 7, the first upper connecting member 811 is positioned so as to overlap in the left-right direction with the metal rod 71 embedded in the rigid member 7.

The first upper connecting member 811 extends straight up from the connection position with the rigid member 7, then bends diagonally upward to the right at the first bend 813. The first upper connecting member 811 then bends straight up at the second bend 814, then reaches the right side of the upper frame 22. The second upper connecting member 812 similarly extends straight up from the connection position with the rigid member 7, then bends diagonally upward to the left at the first bend 815, and bends straight up at the second bend 816, then reaches the left side of the upper frame 22.

The first upper connecting member 811 and the second upper connecting member 812 are small-diameter rod-shaped members made of metal. The rigid member 7 and the first upper connecting member 811 and the second upper connecting member 812 are integrally formed by, for example, insert molding.

The lower connecting member 82 includes a first lower connecting member 821 on the right side and a second lower connecting member 822 on the left side. The first lower connecting member 821 and the second lower connecting member 822 on the left side have bilaterally symmetrical shapes with respect to the center line of the seat back 11. Below, the structure of the first lower connecting member 821 will be described in detail, and the description of the structure of the second lower connecting member 822 will be omitted where appropriate.

The first lower connecting member 821 connects the lower end of the base 69 to the right portion of the lower frame 23. The connection position between the first lower connecting member 821 and the base 69 is the right portion of the base 69.

The first lower connecting member 821 protrudes outward to the right from the right side of the base 69, then curves in a U-shape. As shown in FIG. 2, the first lower connecting member 821 is attached to a first mounting portion 231 provided on the right side of the lower frame 23. Similarly, the second lower connecting member 822 protrudes outward to the left from the left side of the base 69, then curves in a U-shape and is attached to a second mounting portion 232 provided on the left side of the lower frame 23.

The first lower connecting member 821 and the second lower connecting member 822 are also small-diameter rod-shaped members made of metal. The base 69 and the first lower connecting member 821 and the second lower connecting member 822 are integrally formed by, for example, insert molding.

The pressure-receiving member 4 is fixed to the frame 2 by a pair of upper connecting members 81 and a pair of lower connecting members 82. When the pressure-receiving member 4 receives an impact load from the back of the occupant 9, for example, during a rear-end collision of the vehicle, the pair of upper connecting members 81 and the pair of lower connecting members 82 elastically deform, allowing the pressure-receiving member 4 to displace rearward. The displacement of the pressure-receiving member 4 reduces the impact load acting on the neck of the occupant 9 during the collision.

In addition, instead of including a pair of connecting members, the first upper connecting member 811 and the second upper connecting member 812, as described above, the upper connecting member 81 may be a single member by connecting the lower ends of the first upper connecting member 811 and the second upper connecting member 812 to each other. Similarly, instead of including a pair of connecting members, the first lower connecting member 821 and the second lower connecting member 822, the lower connecting member 82 may be a single member by connecting the left and right first lower connecting member 821 and second lower connecting member 822 to each other.

As shown in Figure 4 or the right diagram of Figure 6, an intermediate connecting member 83 is located behind the base 69. The intermediate connecting member 83 connects the rigid member 7 to the lower end of the base 69. The intermediate connecting member 83 includes a first intermediate connecting member 831 on the right side and a second intermediate connecting member 832 on the left side. The first intermediate connecting member 831 and the second intermediate connecting member 832 have bilaterally symmetrical shapes with respect to the center line of the seat back 11. Below, the structure of the first intermediate connecting member 831 will be described in detail, and a description of the structure of the second intermediate connecting member 832 will be omitted where appropriate.

The upper end of the first intermediate connecting member 831 is fixed to the rigid member 7. The fixed position of the first intermediate connecting member 831 in the left-right direction is the same as the fixed position of the first upper connecting member 811. The first intermediate connecting member 831 extends straight down from the rigid member 7 and then bends diagonally downward to the right. The first intermediate connecting member 831 then bends straight down again and reaches the third mounting portion 691 provided at the lower end of the base 69. The third mounting portion 691 and the first mounting portion 231 are located at approximately the same left-right position. The second intermediate connecting member 832 extends straight down from the rigid member 7 and then bends diagonally downward to the left, then bends straight down again and reaches the fourth mounting portion 692 provided at the lower end of the base 69. The fourth mounting portion 692 and the second mounting portion 232 are located at approximately the same left-right position.

The intermediate connecting member 83 increases the rigidity of the pressure-receiving member 4, which includes the base 69 and the rigid member 7, and also supports the lumbar support 40.

The lumbar support 40 is located behind the pressure-receiving member 4 and supports the lumbar region of the occupant 9 via the pressure-receiving member 4. The lumbar support 40 is generally V-shaped when viewed from behind. The right and left sides of the lumbar support 40 are engaged with the first intermediate connecting member 831 and the second intermediate connecting member 832, respectively. The lumbar support 40 can be adjusted in the vertical direction along the first intermediate connecting member 831 and the second intermediate connecting member 832. By adjusting its position according to the physique of the occupant 9, the lumbar support 40 can adequately support the lumbar region of the occupant 9. As shown in FIG. 6 , the lumbar support 40 moves up and down between an upper limit UL and a lower limit LL. The upper limit UL is the position where the lumbar support 40 interferes with the rigid member 7. The lower limit LL is the position where the first intermediate connecting member 831 and the second intermediate connecting member 832 bend. The upwardly bulging fixing portion 68 positions the upper limit UL at a higher position. The fixing portion 68 expands the lift range of the lumbar support 40.

A gearbox 41 containing an electric motor is located below the lumbar support 40. The electric motor is the drive source for raising and lowering the lumbar support 40. The gearbox 41 has a worm gear 42. The worm gear 42 extends directly upward from the gearbox 41. The upper end of the worm gear 42 is fixed to the center of the lower end of the lumbar support 40. When the electric motor rotates, the lumbar support 40 rises and falls together with the worm gear 42. The occupant can raise and lower the lumbar support 40 by operating a switch.

(Seatback structure that supports the occupant's back while reducing discomfort to the occupant)
As described above, the pressure-receiving member 4 is attached to the frame 2 via the connecting member 8. The pressure-receiving member 4 receives the load from the back of the occupant 9 and supports the back of the occupant 9.

The pressure-receiving member 4 has a main body 6 and a rigid member 7. The rigid member 7 is fixed to the rear side of the main body 6 at a position corresponding to the thorax 91 of the occupant 9. The rigid member 7 also extends in the width direction of the seat back 11 and is connected to the frame 2 by connecting members 8 at multiple locations at different positions in the width direction. Because the main body 6 is connected to the frame 2 via the rigid members 7, the pressure-receiving member 4 can firmly support the back of the occupant 9. For example, in the event of a rear-end collision of the vehicle, the pressure-receiving member 4 can support the back of the occupant 9 that receives the impact load. As mentioned above, in the event of a rear-end collision, the pressure-receiving member 4 can move rearward due to the elastic deformation of the connecting members 8.

On the other hand, when the vehicle is running normally, the load from the back of the occupant 9 is received by the main body 6 of the pressure-receiving member 4, which has a relatively low rigidity. This prevents the reaction force on the back of the occupant 9 from becoming too strong, reducing the discomfort felt by the occupant 9.

Therefore, the vehicle seat back 11 can reliably support the back of the occupant 9 while reducing discomfort felt by the occupant 9.

Furthermore, in the main body 6 having a base 69 and side pieces 60, the central portion of the main body 6, i.e., the base 69, has relatively high rigidity, while both side portions, i.e., the side pieces 60, have relatively low rigidity. The connection point between the rigid member 7 and the connecting member 8 is on the central side corresponding to the position of the base 69, and the rigid member 7 is fixed to the base 69 closer to the center than the connection point between the rigid member 7 and the connecting member 8. This allows the pressure-receiving member 4 to firmly support the central side of the back of the occupant 9 during normal vehicle driving.

In addition, because the rigid member 7 extends elongatedly in the width direction, the load from the occupant 9 input through the main body 6 can be dispersed. This also allows the pressure-receiving member 4 to firmly support the back of the occupant 9.

Due to the embedded metal rods 71, the rigidity of both sides of the rigid member 7 is relatively high, while the rigidity of the central portion is relatively low. The load from the back of the occupant 9 is input to the central portion of the rigid member 7, which has relatively low rigidity. Because the rigidity of the rigid member 7 varies in the longitudinal direction, the central portion and both side portions of the rigid member 7 displace in opposite directions when a load is input. In other words, when the central portion displaces rearward, the both side portions displace forward, and when the central portion displaces forward, the both side portions displace rearward, allowing the rigid member 7 to withstand the load. The pressure-receiving member 4 can firmly support the back of the occupant 9.

In addition, because the fixing portion 68 of the base 69 is located higher than the position of the side piece 60, the rigid member 7 fixed to the upper end portion of the main body 6 can firmly support the pressure-receiving member 4.

(Seatback structure that suppresses changes in occupant posture when cornering without compromising ride comfort)
As shown in Fig. 8 , the pad 3 has a reinforcement reduction portion 321. The reinforcement reduction portion 321 reduces the reinforcement of the reinforcing member 32 attached to the rear surface of the foam member 31. The reinforcement reduction portion 321 in Fig. 8 is a notch formed in the reinforcing member 32.

As shown in Figure 2, the reinforcing lowered portions 321 are located at positions overlapping the first side pieces 61 on both the left and right sides when viewed from a direction perpendicular to the surface of the seat back 11. As shown in Figure 5, this position corresponds to the lower part of the thorax 91 of the occupant 9. The two reinforcing lowered portions 321 are located symmetrically with respect to the center line of the seat back 11.

In the illustrated example, the reinforcing reduced portion 321 has an approximately quarter-circular shape when viewed from behind. However, the shape of the reinforcing reduced portion 321 is not limited to the illustrated example. The reinforcing reduced portion 321 may have a polygonal, circular, or elliptical shape when viewed from behind.

As mentioned above, the base 69 of the main body 6 of the pressure-receiving member 4 is located in the center of the width of the seat back 11 and supports the center of the back of the occupant 9. Each side piece 61-67 is located on either side of the base 69 and supports each side of the back of the occupant 9.

When the vehicle is traveling straight, the pressure-receiving member 4 receives the load from the entire back of the occupant 9 via the pad 3. As described above, the pad 3 has a foam member 31 and a reinforcing member 32. The load from the back of the occupant 9 is received primarily by the base 69 of the pressure-receiving member 4 as the foam member 31, reinforced by the reinforcing member 32, undergoes compressive deformation. The pad 3 and the pressure-receiving member 4 receive the load from the back of the occupant 9 over their entire wide surfaces. Therefore, when the vehicle is traveling straight, the seat back 11 can firmly support the back of the occupant 9 without applying a strong reaction force to the back of the occupant, which would adversely affect ride comfort.

When the vehicle turns, the posture of the occupant 9, i.e., the driver or passenger, tends to change in a direction that causes the thorax 91 to rotate around the spine and/or tilt left or right. As the posture of the occupant 9 changes, a load is locally input to the seat back 11 from the side of the occupant 9's back.

Localized loads from the sides of the occupant's 9 back are input to the pad 3 at the reinforcement lowering portion 321, which corresponds to the thorax 91. At the initial stage of input of the localized load, the foam member 3 undergoes significant compressive deformation at the reinforcement lowering portion 321. This prevents a strong reaction force from acting on the occupant 9 at the initial stage of input of the localized load.

After the foam member 31 is compressed and deformed, the local load from the side of the occupant's 9 back is received primarily by the first side piece 61 of the pressure-receiving member 4. A reaction force is then applied from the pressure-receiving member 4 to the side of the occupant's 9 back through the pad 3. This suppresses changes in the posture of the occupant 9.

As a result, this seat back 11 can firmly support the back of the occupant 9 and suppress changes in posture while suppressing strong reaction forces on the occupant 9 when the vehicle is turning.

On the other hand, the reinforcement lowering portion 321 is provided partially at a specific location on the pad 3. When a load is input to the seat back 11 from the entire back of the occupant 9, such as when the vehicle is traveling straight, the reinforcement lowering portion 321 does not substantially function. The seat back 11 does not deteriorate the ride comfort when the vehicle is traveling straight.

Therefore, the seat back 11 can suppress changes in the posture of the occupant 9 when turning without compromising ride comfort when traveling straight or turning.

Furthermore, the reinforcement lowering portions 321 are located on both sides of the center line of the seat back 11 in the width direction. In other words, the reinforcement lowering portions 321 are located on both the right and left sides of the back of the occupant 9. When turning right and left, the seat back 11 can suppress changes in the posture of the occupant 9.

In addition, the first side piece 61, which overlaps the reinforcing lowering portion 321, has higher rigidity than the second side piece 62. The highly rigid first side piece 61 can apply sufficient reaction force to the side of the back of the occupant 9. As a result, changes in the posture of the occupant 9 can be suppressed when the vehicle turns.

In addition, because the reinforcing lowering portion 321 is located behind the thorax 91 of the occupant 9, the first side piece 61 of the pressure-receiving member 4 can apply a reaction force to the thorax 91, which tends to displace when the vehicle turns. The seat back 11 can effectively suppress changes in the posture of the occupant 9.

Because each side piece 61-67 extends forward and outward in the width direction from the base 69, the first side piece 61 can apply a reaction force to the area extending from the side of the occupant's 9 back to the side of the occupant's 9 body. The seat back 11 can effectively suppress changes in the posture of the occupant 9 in the direction in which the thorax 91 rotates and/or in the direction in which the thorax 91 tilts left or right.

Furthermore, by using the nonwoven fabric as the reinforcing member 32 to control the compression amount of the foam member 31, the vehicle seat back 11 appropriately supports the back of the occupant 9, improving ride comfort. The notches formed in the nonwoven fabric as the reinforcing lowering portions 321 do not restrain the rear surface of the foam member 31, thereby reducing the reaction force when a local load is input from the back of the occupant 9. As a result, as described above, the reinforcing lowering portions 321 initially reduce the reaction force on the back of the occupant 9 in response to the local load input when the vehicle turns. Thereafter, the pressure-receiving member 4, mainly the first side piece 61, can apply sufficient reaction force to the back of the occupant 9, suppressing changes in the posture of the occupant 9.

The reinforcing lowering portion 321 is not limited to a notch, and may be a slit formed in the reinforcing member 32, as shown in FIG. 9. While the slit in FIG. 9 is a sideways U-shape, the slit may also be, for example, an L-shape. Like the slit, the slit also releases the constraint on the rear surface of the foam member 31 by the reinforcing member 32. Therefore, as described above, in response to localized load input during vehicle cornering, the reaction force acting on the back of the occupant 9 is initially reduced, and then, a sufficient reaction force can be applied to the back of the occupant 9, mainly by the side pieces 60 of the pressure-receiving member 4, thereby suppressing changes in the posture of the occupant 9.

1. Vehicle seat back 2. Frame (seat back frame)
3 Pad 31 Foam member 32 Reinforcement member 321 Reinforcement lowering portion 4 Pressure receiving member 51 Airbag 6 Main body 60 Side piece 61 First side piece (specific side piece)
68 Fixing portion 69 Base portion 7 Rigid member 8 Connecting member 9 Occupant 91 Thorax

Claims (7)

A pad that supports the back of the occupant,
a pressure-receiving member located behind the pad and receiving a load from the back of the occupant via the pad,
The pad includes an elastically deformable foam member and a reinforcing member attached to a rear surface of the foam member and reinforcing the foam member,
The pressure-receiving member has a base portion located at a center portion in a width direction of the seat back, and a plurality of side pieces extending outward in the width direction from both sides of the base portion,
The pad has a reinforcement reducing portion that reduces the reinforcement of the reinforcing member at a position that overlaps with a part of the side piece when viewed from a direction perpendicular to the surface of the seat back. The vehicle seat back according to claim 1,
The vehicle seat back, wherein the reinforcing lowered portions are located on both sides of the center line of the seat back in the width direction. The vehicle seat back according to claim 1 or 2,
The side pieces are arranged at intervals in the up-down direction on both sides of the base,
The reinforcing lowered portion overlaps with the specific side piece on each side of the base portion,
The specific side piece has higher rigidity than the side piece adjacent to the specific side piece. The vehicle seat back according to any one of claims 1 to 3,
The vehicle seat back, wherein the reinforcement lowering portion is positioned behind the thorax of the occupant. The vehicle seat back according to any one of claims 1 to 4,
The side pieces extend forward and outward in the width direction from the base portion. The vehicle seat back according to any one of claims 1 to 5,
the reinforcing member is a nonwoven fabric,
The vehicle seat back, wherein the reinforcing lowered portion is a notch or a slit formed in the nonwoven fabric. The vehicle seat back according to any one of claims 1 to 6,
The vehicle seat back further comprises an airbag for seat ventilation positioned between the pad and the pressure-receiving member.