JP7614904B2 - Vehicle seat - Google Patents

Description

The present invention relates to a vehicle seat that is installed in a vehicle such as an automobile and in which a passenger sits.

As an example of prior art related to vehicle seats, Patent Document 1 describes a method in which a swingable board is placed in the center of a seat cushion having a seating surface, and a seat cushion lifting means is used to rotate the board in a direction in which the front end portion rises, thereby preventing the occupant from moving forward of the vehicle when the vehicle suddenly decelerates.
Patent document 2 describes how, in order to restrict the forward movement of the occupant, an airbag module is provided on the floor below the seat cushion, and a plate material that can be freely opened forward is provided on the upper part of the airbag module, centered on a hinge at the rear end, so that in the event of a collision, the airbag will cause the plate material to be inclined at a certain forward-open position.
Patent document 3 describes a restraint member that is positioned rearward of a front cross member located within the front portion of the seat cushion and supported on the front cross member so that it can swing up and down, and that causes the restraint member to swing upward and stand up in response to the webbing connecting the restraint member and the rear cross member being pushed down by the inertial force of the occupant during a vehicle collision.

Japanese Patent Application Publication No. 5-238297 JP-A-7-81466 JP 2014-104885 A

During a frontal collision of a vehicle, rear seat occupants may behave differently than front seat occupants.
Specifically, the distance between the knees of rear seat passengers and the seat back of the front seat changes depending on the seat position and the angle of the seat back of the front seat, and the way in which the lower body of the rear seat passenger is restrained during a collision also changes. As a result, the position of the seat belt (lap belt) around the waist of the rear seat passenger may also change, and the upper body may not move as desired with the lap belt as the fulcrum.
In particular, if a rear seat passenger's lower back (pelvis area) presses down into the seat cushion during a collision, the lap belt may come off the pelvis and dig into the abdomen, causing increased pressure on the abdomen.

In response to this, if some kind of device were to push up on the occupant's lower back from below during a collision to prevent the pelvis from sinking, it would be possible to prevent the lap belt from rising toward the abdomen, stabilizing the movement of the upper body and preventing pressure on the abdomen.
However, when the occupant is pushed up in the manner described above in the conventional technology, various hard members are placed inside the seat cushion, which gives the occupant a foreign body sensation and discomfort, compromising the comfort of the vehicle during normal use.
In view of the above problems, an object of the present invention is to provide a vehicle seat that appropriately controls the posture of an occupant during a collision without impairing the riding comfort.

In order to solve the above-mentioned problems, the vehicle seat of the present invention is a vehicle seat installed in a vehicle having a collision detection unit that detects a vehicle collision, and comprises a seat cushion formed of an elastic material on which an occupant's hips are placed, and a hip push-up mechanism that pushes up a lower area of the hips in the seat cushion from below in response to detection of the collision, the hip push-up mechanism having a protrusion that protrudes downward at a lower part of the seat cushion and has a shape in which the lower part is narrower than the upper part, a webbing that is formed of a flexible material and is arranged in a slack state so as to detour around the protrusion before the occurrence of the collision, and a tension generating unit that generates tension in the webbing in response to detection of the collision.
With this structure, during a collision, the webbing is pulled by the tension generating portion and approaches a straight state, sliding over the surface of the protrusion, scooping up the protrusion and pushing it upward, thereby pushing up the occupant's waist from below, stabilizing the occupant's posture and preventing the lap belt from coming off the occupant's pelvis and rising toward the abdomen.
Furthermore, the webbing can be constructed as a relatively soft member having flexibility, which can prevent the occupant from feeling a foreign body sensation during normal use of the vehicle, thereby improving the ride comfort.
Furthermore, compared to cases where measures are taken on the belt side to suppress the rise of the lap belt, this improves the effect of preventing the lap belt from rising, thereby ensuring stable occupant restraint, and can provide good results even when there are differences in occupant physiques.

In the present invention, the protrusion can be configured so that at least a portion of the protrusion is inserted into a recess formed in a vehicle body structural member arranged below the seat cushion, and the webbing is positioned between a surface of the protrusion and an inner surface of the recess.
This makes it possible for the webbing to maintain its shape before a collision while detouring around the protruding portion, thereby making it possible to more reliably obtain the above-mentioned effects.

In the present invention, the protrusion may be configured to be molded in advance integrally with the seat cushion.
In the present invention, the protrusion may be formed by elastic deformation of the seat cushion due to the weight of the occupant.
According to each of these inventions, the above-mentioned effects can be appropriately obtained with a simple configuration that suppresses an increase in the number of parts.
Furthermore, since the protruding portion is integrally formed with the seat cushion from an elastic material, it is possible to prevent the occupant from feeling a foreign body sensation.

In the present invention, the tension generating portion may be configured to wind up the webbing in cooperation with a seatbelt pretensioner that winds up a seatbelt worn by an occupant in response to detection of the collision.
According to this, there is no need to provide a dedicated actuator independently in the tension generating section, nor a dedicated control device, etc., and the device configuration can be simplified.

As described above, the present invention provides a vehicle seat that appropriately controls the posture of the occupant during a collision without impairing the ride comfort.

1 is a schematic exploded perspective view of a first embodiment of a vehicle seat to which the present invention is applied; 1 is a block diagram showing a schematic diagram of a system configuration in a vehicle having a vehicle seat according to a first embodiment; 2 is a perspective view showing a schematic structure of a bobbin portion of a seatbelt pretensioner provided in the vehicle seat of the first embodiment; FIG. FIG. 2 is a diagram illustrating the periphery of a protruding portion in the vehicle seat of the first embodiment, in a state before a collision; FIG. 2 is a diagram showing the periphery of a protruding portion in the vehicle seat of the first embodiment, in a state after a collision; 5A to 5C are diagrams illustrating an example of the behavior of an occupant in a vehicle seat according to the first embodiment and a comparative example of the present invention during a frontal collision. FIG. 13 is a diagram showing the periphery of a protruding portion in a vehicle seat according to a second embodiment of the present invention, in a state before a collision.

First Embodiment
Hereinafter, a first embodiment of a vehicle seat to which the present invention is applied will be described.
The vehicle seat of the first embodiment is a so-called bench seat provided as a rear seat (second row seat) in an automobile such as a passenger car.

FIG. 1 is a schematic exploded perspective view of a vehicle seat according to a first embodiment.
The seat 100 includes a seat cushion 110, a seat back 120 (not shown in FIG. 1, see FIG. 6), and the like.
The seat cushion 110 has a seating surface portion on which the lumbar region (pelvis region) and thighs of an occupant are placed.
The seat cushion 110 has an overall shape like a panel extending in the vehicle front-rear direction and in the vehicle width direction.
The seat cushion 110 is formed of a porous material having elasticity, such as urethane foam.
The seat cushion 110 is partially provided with a core material made of metal or the like to maintain its shape, and is covered with a fabric such as woven fabric or knitted fabric, or with a skin such as leather.

The seat cushion 110 is formed with a protrusion 111 .
The protrusion 111 is formed as a projection that protrudes downward from the lower surface of the seat cushion 110 .
The protruding portion 111 is formed, for example, in a circular shape when viewed from above, and has a dome-like surface that is a spherical convex curved surface.
Due to this configuration, the protruding portion 111 has a shape in which the lower portion is narrower (reduced in diameter) than the upper portion.
The protruding portion 111 is formed immediately below the area on which the occupant's lower back, including the pelvis, and buttocks are placed when seated.
As shown in FIG. 1, in the first embodiment, the protrusions 111 are arranged at, for example, two locations spaced apart in the vehicle width direction.

The seat back 120 is a portion that protrudes upward from the vicinity of the rear end of the seat cushion 110, and is a portion that mainly supports the back of an occupant.
The seat back 120 is formed from an elastic porous material similar to the seat cushion 110, and is covered with a skin.

The seat cushion 110 is placed on the upper surface of a step 11 formed on a floor panel 10 which is a vehicle body structural member constituting the floor surface of the vehicle compartment.
The step portion 11 is provided at the rear of the floor panel 10 and is a portion that protrudes upward in a stepped shape from the floor panel 10, and is formed integrally with the rest of the floor panel 10, for example, by press molding a steel plate.
A recess 12 is formed on the upper surface of the step portion 11 .
The recess 12 is formed by recessing the upper surface of the step portion 11 downward in a cup shape, and when viewed from above, it has a planar shape that is, for example, a circle concentric with the central axis of the protrusion 111.
A protrusion 111 of a seat cushion 110 is inserted into the recess 12 .
The recesses 12 are provided at, for example, two locations spaced apart in the vehicle width direction in accordance with the arrangement of the protrusions 111 .
The side surface of the recess 12 is formed in a tapered shape (like the side surface of a truncated cone) with the lower portion narrower (reduced in diameter) than the upper portion.
The bottom surface of the recess 12 is a flat surface disposed substantially along a horizontal plane.
During normal use of the vehicle (non-crash), the lower end of the protrusion 111 may come into contact with the bottom surface of the recess 12 due to elastic deformation of the seat cushion 110 caused by the weight of the occupant.

Between the side portion (inner surface portion) of the recess 12 and the outer surface of the protrusion 111, a webbing 130, which will be described below, is provided in order to lift the occupant's waist (pelvic area) and stabilize the occupant's posture in the event of a frontal collision of the vehicle.
The webbing 130 is disposed between the step portion 11 of the floor panel 10 and the seat cushion 110, extending in the front-rear direction of the vehicle.
A portion of the middle portion of the webbing 130 is housed inside the recess 12 .
For example, a pair (two pieces) of webbing 130 are arranged per recess 12 .
A front portion 131 of the webbing 130 is fixed to the front end portion of the step portion 11 on the front side of the recess 12 .
A rear portion 132 of the webbing 130 is wound around a bobbin (not shown) that winds up and applies tension to the webbing 130 in the event of a frontal collision of the vehicle.
The spacing in the vehicle width direction of the rear portion 132 is set narrower than the spacing in the middle portion of the webbing 130 before a collision.

FIG. 2 is a block diagram that illustrates a system configuration in a vehicle having the vehicle seat of the first embodiment.
The vehicle includes an airbag control unit 200, a collision sensor 210, an airbag inflator 220, a seatbelt pretensioner 230, and the like.

The airbag control unit 200 comprehensively controls an airbag device that deploys and inflates an airbag, which is a bag made of fabric panels, to restrain an occupant in the event of a vehicle collision.
The airbag control unit 200 is configured as a microcomputer having, for example, an information processing section such as a CPU, a storage section such as a RAM or a ROM, an input/output interface, and a bus connecting these.

The collision sensor 210 is a collision detection unit that has acceleration sensors provided in various parts of the vehicle body and detects significant acceleration (shock) caused by a collision between the vehicle and an object such as another vehicle.
The airbag inflator 220 has, for example, a chemical gas generator, and blows deployment gas into an airbag (not shown) that is stored in an interior member in a folded state before a collision, causing it to deploy and inflate.
The seatbelt pretensioner 230 has a bobbin 231 (see FIG. 3, described later) that is driven by, for example, a chemical actuator, and winds up the seatbelt B (see FIG. 6) to apply tension when the vehicle crashes.

The airbag control unit 200 determines the occurrence and type of collision (frontal collision, side collision, rear collision, etc.) based on the output of the collision sensor 210, and determines whether or not the airbag needs to be deployed and whether or not the seatbelt pretensioner 230 needs to be activated.
When the airbag control unit 200 determines that it is necessary to deploy an airbag, it outputs an operation command to the airbag inflator 220 of that airbag, and when it determines that it is necessary to activate the seatbelt pretensioner 230, it outputs an operation command to the seatbelt pretensioner 230.

FIG. 3 is a perspective view that illustrates a schematic structure of a bobbin portion of a seatbelt pretensioner provided in the vehicle seat of the first embodiment.
The bobbin 232 around which the rear portion 132 of the webbing 130 described above is wound is attached coaxially to the bobbin 231 that winds up the seat belt B of the seat belt pretensioner 230 so as to extend in the direction of the rotation axis, and is configured to pull the webbing 130 in conjunction with the pulling of the seat belt B by the seat belt pretensioner 230.
When the seatbelt pretensioner 230 is activated, the bobbins 231, 232 rotate together in the counterclockwise direction as shown by the arrow in FIG. 3, and wind up and pull the seatbelt B and the webbing 130, respectively.
The seatbelt pretensioner 230 functions as a tension generating unit of the present invention.
The airbag control unit 200 and the seat belt pretensioner 230 cooperate with the protrusion 111 and webbing 130 of the seat cushion 110 described above to function as a lumbar push-up mechanism that presses the lower area of the occupant's lumbar region on the seat cushion 110 from below in response to detection of a collision.

The operation of the above-mentioned waist push-up mechanism will now be described.
FIG. 4 is a diagram showing the vicinity of the protruding portion in the vehicle seat of the first embodiment, illustrating a state before a collision.
Fig. 4(a) shows a cross section seen by cutting the center of the protruding portion 111 on a plane along the vehicle width direction and the vertical direction, and Fig. 4(b) shows a cross section taken along the line b-b in Fig. 4(a). Note that in Fig. 4(b), the protruding portion 111 is omitted from the illustration (same as Fig. 5).
Before a collision, the middle portion of the webbing 130 is curved in an arc shape and arranged in a slack state along the inner circumferential surface of the recess 12 so as to bypass the protruding portion 111 .
The pair of webbings 130 are arranged on both sides of the protruding portion 111 in the vehicle width direction.

FIG. 5 is a diagram showing the vicinity of the protruding portion in the vehicle seat of the first embodiment, illustrating a state after a collision.
After a collision, the webbing 130 is pulled and tensioned by the seatbelt pretensioner 230, and the slack is removed and the webbing approaches a straight state.
At this time, the webbing 130 clamps and tightens the protrusion 111 in the vehicle width direction, slides along the surface of the protrusion 111, and moves from the base side (upper side) of the protrusion 111 to the tip side (lower side), and the protrusion 111 is scooped up by the tension of the webbing 130 and pushed upward.
As a result, the lumbar region of the occupant is pushed up, and the posture of the occupant is displaced in a direction in which the pelvis rises.

The effects of the first embodiment will be described below in comparison with a comparative example of the present invention which will be described below.
In the comparative example, parts common to the first embodiment are given the same reference numerals and description thereof will be omitted.
The vehicle seat of the comparative example does not have the hip push-up mechanism of the first embodiment.
FIG. 6 is a diagram showing an example of the behavior of an occupant in a vehicle seat according to the first embodiment and a comparative example of the present invention during a frontal collision.
FIG. 6A shows a comparative example, and FIG. 6B shows the first embodiment.

As shown in FIG. 6, the seat belt B has a shoulder belt portion Bs and a lap belt portion Bl.
The shoulder belt portion Bs is a portion that mainly restrains the position of the occupant P, and is disposed obliquely along the front of the occupant P's chest.
The lap belt portion Bl is a portion that mainly restrains the waist of the occupant P, and in a normal state, is disposed in front of the pelvis of the occupant P in the vehicle width direction.

In general, rear seats often have a seat cushion with lower rigidity in the vertical direction than front seats, and the lumbar region of the occupant P tends to sink more.
In the comparative example shown in Figure 6 (a), when an occupant P moves forward relative to the vehicle body and seat 100 due to significant vehicle deceleration caused by a collision, the lower back sinks into the seat cushion 110, causing the position of the pelvis to drop.
As a result, the lap belt portion Bl may rise relative to the waist of the occupant P, causing the lap belt portion Bl to come into contact with and press against the abdomen.

In contrast, in the first embodiment shown in FIG. 6(b), during a collision, the lumbar push-up mechanism presses the area of the seat cushion 110 on which the lumbar region is placed from below, thereby pushing the lumbar region and pelvis of the occupant P upward, thereby preventing the occupant P from sinking into the seat cushion 110 as in the comparative example.
This suppresses changes in the posture of the occupant P, prevents the lap belt portion Bl from coming off the front part of the pelvis, and prevents pressure on the abdomen of the occupant P.

As described above, according to the first embodiment, the following effects can be obtained.
(1) During a collision, the webbing 130 is pulled by the seatbelt pretensioner 230 and approaches a straight state, and while sliding on the surface of the protruding portion 111, it scoops up the protruding portion 111 and pushes it upward, thereby pushing up the pelvic region of the occupant P from below and stabilizing the posture of the occupant P, and preventing the lap belt portion Bl from coming off the pelvic region of the occupant P and rising toward the abdomen. This makes it possible to prevent the abdomen of the occupant P from being compressed.
Furthermore, the webbing 130 can be configured as a relatively soft member having flexibility, which can prevent the occupant from feeling a foreign body sensation during normal use of the vehicle, thereby improving the ride comfort.
(2) The protrusion 111 is inserted into a recess 12 formed in a step 11 of the floor panel 10, at least a portion of which is arranged under the seat cushion 110, and the webbing 130 is arranged between the surface of the protrusion 111 and the inner surface of the recess 12. This makes it possible for the webbing 130 to maintain its shape before a collision by bypassing the protrusion 111, thereby making it possible to more reliably obtain the above-mentioned effects.
(3) Since the protrusion 111 is molded integrally with the seat cushion 110 in advance, the above-mentioned effects can be appropriately obtained with a simple configuration that suppresses an increase in the number of parts.
Furthermore, since the protruding portion 111 is integrally formed with the seat cushion 110 from an elastic material, it is possible to prevent the passenger from feeling a foreign body sensation.
(4) By winding up the webbing 130 using a bobbin that is linked to the seatbelt pretensioner 230, there is no need to provide a dedicated actuator or a dedicated control device, etc., and the device configuration can be simplified.

Second Embodiment
Next, a second embodiment of a vehicle seat to which the present invention is applied will be described.
In the second embodiment, the same reference numerals are used for the parts common to the first embodiment described above, and the description will be omitted, and the differences will be mainly described.
FIG. 7 is a diagram showing the periphery of a protruding portion in a vehicle seat according to the second embodiment, and shows a state before a collision (a diagram of a portion corresponding to FIG. 4(a) in the first embodiment).
In the second embodiment, instead of forming the protrusion 111 in advance on a part of the seat cushion 110 as in the first embodiment, the lower surface of the seat cushion 110 is formed, for example, flat.
When an occupant sits on the seat cushion 110, the load W causes the seat cushion 110 to elastically deform (the outer shape after deformation is shown by a dashed line), causing the lower part of the seat cushion 110 to protrude into the recess 12 of the floor panel 10, thereby forming a protrusion 111a having the same function as the protrusion 111 of the first embodiment.
In the second embodiment described above, the same effects as those of the first embodiment can be obtained.

(Modification)
The present invention is not limited to the above-described embodiments, and various modifications and variations are possible, which are also within the technical scope of the present invention.
(1) The configurations of the vehicle seat and the vehicle are not limited to the above-described embodiment and may be modified as appropriate.
For example, the shape, structure, material, manufacturing method, arrangement, quantity, etc. of each member constituting the vehicle seat can be changed as appropriate.
(2) Although the vehicle seat in each embodiment is, for example, a second row seat of a passenger vehicle, the present invention can also be applied to a first row seat or a third row seat or seat thereafter. In addition, the vehicle is not limited to a passenger vehicle and may be another type of vehicle.
(3) In each embodiment, the webbing is provided in addition to the seatbelt pretensioner and is pulled by a bobbin that is linked to the seatbelt pretensioner. However, this is not limited to the above, and tension may be applied to the webbing by an actuator that is independent of the seatbelt device.
(4) In each embodiment, the shape of the protrusion is, for example, a dome shape having a spherical convex curved surface. However, the shape of the protrusion is not limited to this and can be changed as appropriate.
For example, the protrusion may be in the shape of a cone or a truncated cone tapering downward.
(5) In each embodiment, the webbing is configured to sandwich the protruding portion in the vehicle width direction. However, this is not limited to this, and the webbing may be configured to sandwich the protruding portion in the front-to-rear direction, or in another direction, for example.

REFERENCE SIGNS LIST 10 floor panel 11 stepped portion 12 recessed portion 100 seat 110 seat cushion 111, 111a protruding portion 120 seat back 130 webbing 131 front portion 132 rear portion 200 airbag control unit 210 collision sensor 220 airbag inflator 230 seatbelt pretensioner 231, 232 bobbin B seatbelt Bs shoulder belt portion Bl lap belt portion W load

Claims (5)

A vehicle seat provided in a vehicle having a collision detection unit for detecting a vehicle collision,
a seat cushion formed of an elastic material on which a passenger's hips are placed;
a lumbar region pushing-up mechanism that pushes up a lower region of the lumbar region of the seat cushion from below in response to detection of the collision,
The waist lifting mechanism includes:
a protruding portion that protrudes downward from a lower portion of the seat cushion and has a shape in which the lower portion is narrower than the upper portion;
a webbing formed of a flexible material and arranged in a slack state so as to detour around the protrusion before the occurrence of the collision;
a tension generating unit that generates tension in the webbing in response to detection of the collision. At least a portion of the protrusion is inserted into a recess formed in a vehicle body structural member disposed below the seat cushion,
The vehicle seat according to claim 1 , wherein the webbing is disposed between a surface of the protrusion and an inner surface of the recess. The vehicle seat according to claim 1 or 2, wherein the protrusion is molded in advance integrally with the seat cushion. The vehicle seat according to claim 1 or 2, wherein the protrusion is formed by elastic deformation of the seat cushion due to the weight of the occupant. 5. The vehicle seat according to claim 1, wherein the tension generating portion winds up the webbing in cooperation with a seatbelt pretensioner that winds up a seatbelt worn by an occupant in response to detection of the collision.

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