Seat-mounted airbag device

Abstract

The present disclosure provides a seat-mounted airbag device. The seat-mounted airbag device includes an airbag main body having a front-rear chamber and a top-end chamber, wherein the front-rear chamber is deployed from the side of the head of an occupant and toward the front side of the seat by gas injected from an inflator that operates in response to detection or prediction of a vehicle collision, and is disposed at the side of the head of the occupant, and the top-end chamber is deployed from the seat front side end of the front-rear chamber toward the inside in the seat width direction, and is disposed at the seat front side of the face of the occupant. When a load applied to the airbag main body toward the seat front side exceeds a predetermined threshold value in head restraint in which the head of the occupant is restrained, the airbag main body and a seat back frame are linked by a force limiting mechanism that moves the airbag main body toward the seat front side.

Description

Seat-mounted airbag Technical Field

[0001] This disclosure relates to a seat-mounted airbag device. Background Technology

[0002] A side airbag device is known to have an airbag body and an airbag protrusion connected together by a surface tether. In the event of a collision from the front of the vehicle, the airbag body deploys forward from the side of the seat back and is positioned to the side of the occupant's upper body (including the head). The airbag protrusion deploys inward from the airbag body in the width direction of the seat and is positioned in front of the occupant's face (see, for example, Japanese Patent Application Laid-Open No. 2006-008105). Summary of the Invention

[0003] However, since the aforementioned side airbag device uses a structure that restrains the occupant's head only when it moves diagonally forward by means of an airbag protrusion positioned in front of the occupant's face, when the occupant's head is restrained, there are cases where the amount of forward movement of the occupant's head is relatively small compared to the amount of forward movement of the occupant's chest determined by the restraining force of the seat belt, and there are cases where the occupant's neck tilts (flexes) back significantly.

[0004] Therefore, the purpose of this disclosure is to provide a seat-mounted airbag device that can suppress the backward tilting of the occupant's neck when the occupant's head is restrained.

[0005] To achieve the above objectives, the seat-mounted airbag device described in the first aspect of this disclosure includes an airbag body having front and rear chambers and a top chamber. The front and rear chambers are deployed from the side of the occupant's head and toward the front of the seat by gas ejected from an inflation device that operates based on detecting or predicting a vehicle collision, and are positioned at the side of the occupant's head. The top chamber extends inward in the seat width direction from the front end of the front and rear chambers and is positioned at the front of the occupant's face. When head restraint is applied to the occupant's head, if the load applied to the airbag body toward the front of the seat exceeds a predetermined threshold, a force limiting mechanism that moves the airbag body toward the front of the seat connects the airbag body and the seat back frame.

[0006] According to the first method, when a vehicle collision is detected or predicted, the inflation device is activated to eject gas, causing the front and rear chambers to expand from the sides of the occupant's head and towards the front of the seat, and to be positioned at the sides of the occupant's head. Furthermore, the top chamber expands from the front ends of the front and rear chambers towards the inside in the seat width direction and is positioned at the front of the occupant's face. Here, the airbag body and the seat back frame are connected together by a force limiting mechanism. When restraining the occupant's head, if the load applied to the airbag body towards the front of the seat exceeds a predetermined threshold, the force limiting mechanism will move the airbag body towards the front of the seat. Therefore, when restraining the occupant's head, it is possible to suppress the amount of forward movement of the occupant's head relative to the amount of forward movement of the occupant's chest determined by the restraint force of the seatbelt. In other words, a longer head travel distance for the occupant allows for lower load suppression on the occupant's head. This inhibits the backward tilting of the occupant's neck.

[0007] Furthermore, the seat-mounted airbag device described in the second embodiment is, in the seat-mounted airbag device described in the first embodiment, wherein the force limiting mechanism has: a movable member, which includes a supply pipe for supplying gas ejected from the inflation device to the airbag body mounted at the upper end, and the lower end is supported on the seat back frame in a manner that allows rotation in the seat width direction as an axial direction; an energy absorption section, which is disposed between the supply pipe and the seat back frame or between the movable member and the seat back frame, and when the load exceeds a predetermined threshold, allows the movable member to rotate toward the front of the seat while absorbing energy.

[0008] According to the second method, when the occupant's head is restrained, if the load applied to the airbag body towards the front of the seat exceeds a predetermined threshold, the energy absorption unit will allow the movable part to rotate towards the front of the seat while absorbing energy. That is, the movable part and the supply pipe will rotate towards the front of the seat together with the airbag body. Therefore, when the occupant's head is restrained, the occupant's head travel can be longer, thereby suppressing the load acting on the occupant's head. This effectively suppresses the occupant's neck tilt.

[0009] Furthermore, the seat-mounted airbag device described in the third embodiment is, in the seat-mounted airbag device described in the first embodiment, wherein the force limiting mechanism comprises: a supply tube connected to the inflation device fixed to the seat back frame to supply gas ejected from the inflation device to the airbag body; a hose that internally houses the supply tube and connects the inflation device and the airbag body, and has excess length; a reaction plate disposed at the rear seat side end of the airbag body; and an energy absorption section disposed between the reaction plate and the seat back frame, which, when the load exceeds a predetermined threshold, allows the reaction plate to move towards the front of the seat while absorbing energy.

[0010] According to the third method, when the occupant's head is restrained, if the load applied to the airbag body towards the front of the seat exceeds a predetermined threshold, the energy absorption unit allows the reaction plate to move towards the front of the seat while absorbing energy. That is, the reaction plate moves towards the front of the seat together with the airbag body. Therefore, when the occupant's head is restrained, the head travel can be longer, thereby suppressing the load acting on the occupant's head. This effectively suppresses the occupant's neck tilt. Furthermore, although the airbag body disengages from the supply tube when the reaction plate and airbag body move towards the front of the seat together, the hose extends, allowing for a continuous supply of gas to the airbag body. Therefore, even if the airbag body moves towards the front of the seat, the occupant's head restraint can be effectively maintained. Moreover, since no moving parts are required, the structure of the force limiting mechanism is simplified.

[0011] Furthermore, in the fourth embodiment, the seat-mounted airbag device described in the second or third embodiment is configured such that the force limiting mechanism is in a non-operating state under loads on the front side of the seat when the airbag body expands and deploys.

[0012] According to the fourth method, the force limiting mechanism is deactivated under loads directed towards the front of the seat during the airbag's inflating and deployment. Therefore, the force limiting mechanism is more effectively restrained against the loads directed towards the front of the seat during the airbag's inflating and deployment.

[0013] Furthermore, the seat-mounted airbag device described in the fifth embodiment is, in the seat-mounted airbag device described in the fourth embodiment, wherein the energy absorption part includes a plate, the plate absorbs energy by undergoing plastic deformation, and the thickness of a portion of the deformed area of ​​the plate is set to be thicker than the thickness of other deformed areas, so as to be able to withstand the load facing the front side of the seat when the airbag body expands and deploys.

[0014] According to the fifth method, it is configured such that by setting the thickness of the deformable region of a portion of the plate that absorbs energy through plastic deformation to be thicker than the thickness of other deformable regions, it is able to withstand the load toward the front of the seat when the airbag body expands and deploys. Therefore, compared to methods other than setting the thickness of the deformable region of the plate to withstand the load toward the front of the seat when the airbag body expands and deploys, the structure of the energy absorption section is simplified.

[0015] Furthermore, the seat-mounted airbag device described in the sixth embodiment is, in the seat-mounted airbag device described in the fourth embodiment, wherein the force limiting mechanism is configured to include an actuator, the actuator causing the force limiting mechanism to operate when the load exceeds a predetermined threshold.

[0016] According to the sixth method, when the occupant's head is restrained, the force limiting mechanism is activated by an actuator when the load applied to the airbag body towards the front of the seat exceeds a predetermined threshold. Therefore, the force limiting mechanism can be activated more reliably than if a method other than an actuator is used.

[0017] As described above, according to this disclosure, in a seat-mounted airbag device, the occupant's neck can be suppressed from tilting backward when the occupant's head is restrained. Attached Figure Description

[0018] Figure 1 is a side view showing the deployed state of the seat-mounted airbag device according to the first embodiment.

[0019] Figure 2 is a top view showing the deployed state of the seat-mounted airbag device according to the first embodiment.

[0020] Figure 3 is a perspective view showing the structure of the force limiting mechanism of the seat-mounted airbag device according to the first embodiment.

[0021] Figure 4 is a front view of the left half of the structure of the force limiting mechanism of the seat-mounted airbag device according to the first embodiment.

[0022] Figure 5 is a perspective view showing the structure of the energy absorption section in the force limiting mechanism of the seat-mounted airbag device according to the first embodiment.

[0023] Figure 6A is a top view showing the structure of the energy absorption section in the force limiting mechanism of the seat-mounted airbag device according to the first embodiment.

[0024] Figure 6B is a side view showing the structure of the energy absorption section in the force limiting mechanism of the seat-mounted airbag device according to the first embodiment.

[0025] Figure 7 is a side view showing the working state of the force limiting mechanism of the seat-mounted airbag device according to the first embodiment.

[0026] Figure 8 is a graph showing the load-displacement characteristics (FS characteristics) of the occupant's head restraint achieved by the seat-mounted airbag device according to the first embodiment.

[0027] Figure 9 is a side view showing a modified example of the force limiting mechanism in the seat-mounted airbag device according to the first embodiment.

[0028] Figure 10 is an enlarged top view showing a partial disconnection of the structure in the force limiting mechanism of the seat-mounted airbag device according to the first embodiment.

[0029] Figure 11 is a side view showing the deployed state of the seat-mounted airbag device according to the second embodiment.

[0030] Figure 12 is a front view of the left half of the structure of the force limiting mechanism of the seat-mounted airbag device according to the second embodiment.

[0031] Figure 13 is a side view showing the working state of the force limiting mechanism of the seat-mounted airbag device according to the second embodiment. Detailed Implementation

[0032] The embodiments disclosed herein will now be described in detail based on the accompanying drawings. For ease of explanation, the arrow UP, appropriately indicated in the drawings, will represent the direction upwards from the seat, the arrow FR the direction forwards from the seat, and the arrow RH the direction to the right from the seat. Therefore, in the following description, unless otherwise specified, the directions of up / down, front / back, and left / right will be used to represent the up / down, front / back, and left / right directions of a vehicle seat. Furthermore, the left / right direction is synonymous with the seat width direction.

[0033] As shown in Figures 1 and 2, the seat-mounted airbag device (hereinafter referred to simply as "airbag device") 30 of this embodiment is provided on the outer side (left side shown) of the vehicle seat 10 in the seat width direction. Although the vehicle seat 10 of this embodiment is described as a rear seat, the airbag device 30 can also be provided in the front seat. Furthermore, as an example, this rear seat is provided on the right side of the side window (not shown).

[0034] Therefore, the airbag body 32, as described below, passes between the head Ph of the occupant P on the side window and the head of the occupant on the center seat (not shown). Alternatively, the airbag body 32 can also pass between the side window and the head Ph of the occupant P. Furthermore, as an example, "occupant P" in this embodiment refers to an occupant equivalent to the AM50 (50th percentile of adult males in the United States) of a human dummy.

[0035] <First Implementation>

[0036] First, the airbag device 30 according to the first embodiment will be described. As shown in Figures 1 and 2, the vehicle seat 10 has a seat cushion 12 for occupant P to sit on (supporting the buttocks and thighs of occupant P), a seat back 14 for supporting the back of occupant P, and a headrest 16 for supporting the head Ph of occupant P.

[0037] As shown in Figures 3 and 4, the headrest 16 is positioned at the center of the upper part of the seat backrest 14 (refer to Figures 1 and 2) in a height-adjustable manner, along the width of the seat. More specifically, a pair of cylindrical headrest supports 18 are provided at the center of the lower surface of the headrest 16 in the width of the seat.

[0038] Each headrest support 18 is inserted into a generally cylindrical headrest support 26 in a height-adjustable manner and can be fixed at multiple predetermined positions. The headrest support 26 is arranged in a pair on the left and right sides at the center of the upper end of the seat back 14 (the upper frame 24 described later) in the seat width direction. This allows the height of the headrest 16 to be adjusted according to the position of the occupant P's head Ph. Furthermore, a housing 20 for retracting the airbag body 32 (described later) is located on the left side of the headrest 16.

[0039] As shown in Figures 1 and 2, the airbag device 30 has an airbag body 32, which is ejected by gas from the inflation device 28 described later, causing a portion of the housing 20 to rupture and fly out, and deploying forward from the rear side (specifically the left rear side) of the head Ph of the occupant P seated on the vehicle seat 10.

[0040] The airbag body 32 has a front and rear chamber 34 and a top chamber 36. The front and rear chambers 34 extend forward from the left side of the occupant P's head Ph and are positioned to the left of the occupant P's head Ph (between the head Ph of the occupant P on the side window side and the head of the occupant on the center seat side, not shown). The top chamber 36 extends inward from the front end of the front and rear chambers 34 in the seat width direction and is positioned in front of the occupant P's face and to the right of the occupant P's head Ph. In other words, the airbag body 32 is bent into a roughly "J" shape when viewed from above, thereby restraining at least the head Ph of the occupant P.

[0041] Furthermore, the airbag body 32 has a thin, cloth-like upper tether 37 and a thin, cloth-like lower tether 38 (see Figure 1). The upper tether 37 connects the middle portion 36U in the deployment direction in the upper end of the top chamber 36 and the middle portion 34U in the deployment direction in the upper end of the front and rear chambers 34. The lower tether 38 connects the middle portion 36D in the deployment direction in the lower end of the top chamber 36 (see Figure 1) and the middle portion 34D in the deployment direction in the lower end of the front and rear chambers 34 (see Figure 1).

[0042] To be more specific, the upper tether 37 is formed such that, when the airbag body 32 has inflated and deployed, the straight rear end edge 37A that connects the middle part 36U in the deployment direction in the upper end of the top chamber 36 and the middle part 34U in the deployment direction in the upper end of the front and rear chambers 34, when viewed from above, is a roughly right-angled triangle with a hypotenuse.

[0043] Furthermore, the peripheral portion of the upper tether 37, excluding its rear end edge 37A, is sewn onto the upper ends of the front and rear chambers 34 and the top chamber 36, from the middle of the unfolding direction 34U in the upper end of the front and rear chambers 34 to the middle of the unfolding direction 36U in the upper end of the top chamber 36.

[0044] Similarly, the lower tether 38 is formed such that, when the airbag body 32 has inflated and deployed, the straight rear end edge (not shown) that connects the middle part 36D in the deployment direction in the lower end of the top chamber 36 and the middle part 34D in the deployment direction in the lower end of the front and rear chambers 34 when viewed from below is approximately a right-angled triangle with a hypotenuse.

[0045] Furthermore, the peripheral portion of the lower tether 38, excluding its rear end edge, is sewn onto the lower ends of its front and rear chambers 34 and the lower end of its top chamber 36, from the middle of the unfolding direction 34D in the lower end of the front and rear chambers 34 to the middle of the unfolding direction 36D in the lower end of the top chamber 36.

[0046] Furthermore, as shown in Figure 1, since the upper tether 37 is located above the head Ph of occupant P, it will not interfere with (contact) the head Ph of occupant P. In addition, although the lower tether 38 is located at the neck of occupant P, it is made of a thinner fabric as described above, so even if it interferes with (contacts) the neck, the damage to the neck will be low.

[0047] As shown in Figures 3 and 4, side frames 22, which are one of a pair of seat back frames, are provided on the left and right sides inside the seat back 14 with the opening side facing inward in the seat width direction. The side frames 22 extend in the vertical direction and are roughly "U"-shaped when viewed from above in cross-sectional view. Furthermore, at the upper end of the left and right side frames 22, an upper frame 24, which is roughly inverted "U"-shaped when viewed from the front, is provided as one of the seat back frames. A pair of headrest support portions 26 are integrally provided at the center of the upper frame 24 in the seat width direction.

[0048] Furthermore, as shown in Figures 1 to 4, at the lower end of the outer surface of the left-side side frame 22, a movable plate 44, which is a movable component, is supported by a shaft 42 in such a way that it can rotate in the seat width direction as an axial direction. The movable plate 44 constitutes a force limiting mechanism 40. The movable plate 44 is formed as a flat plate extending in the vertical direction, and its width is set to be smaller than the width of the side frame 22.

[0049] Furthermore, an inflation device 28 is fixed to the outer surface of the movable plate 44. That is, the inflation device 28 is formed into a generally bottomed cylindrical shape, and a portion of its outer peripheral surface is integrally mounted on the outer surface of the movable plate 44 via a bracket (not shown) or the like so that its axial part faces the vertical direction.

[0050] The inflation device 28 is electrically connected to the airbag ECU (not shown) installed on the vehicle, and the detection devices such as the acceleration sensor installed on the vehicle (not shown) are also electrically connected to the airbag ECU. Therefore, when a collision is detected by the detection devices, the inflation device 28 will operate via the airbag ECU to instantaneously release gas.

[0051] Alternatively, the inflation device 28 may not be a structure that operates by detecting vehicle collisions, but rather a structure that operates by predicting vehicle collisions using collision prediction sensors (illustrations omitted).

[0052] Furthermore, the lower end of a metal tube 46, serving as a supply tube, is embedded in the nozzle 28A at the upper end of the inflation device 28. The metal tube 46 and the movable plate 44 together constitute a force-limiting mechanism 40. The metal tube 46 is bent into a crank shape with its upper portion laterally in the seat width direction, following the shape of the seat backrest 14. Moreover, the rear end of the airbag body 32 is installed at the upper end 46A of the metal tube 46.

[0053] In other words, the metal tube 46 is configured to supply gas ejected from the inflation device 28 to the airbag body 32 mounted at its upper end, and is configured to allow the airbag body 32 to be positioned close to the head Ph of the occupant P. Furthermore, the rear end and side frame 22 of the airbag body 32 are connected via the metal tube 46 constituting the force limiting mechanism 40 and the movable plate 44 (via the inflation device 28).

[0054] Furthermore, as shown in Figure 2, the movable plate 44, to which the inflation device 28 is fixed, and the portion of the metal tube 46 that is lower than the housing portion 20 are disposed inside the seat back 14. Therefore, as described later, when the movable plate 44 and the metal tube 46 rotate forward, the surface of the seat back 14 will break and rotate forward.

[0055] Furthermore, as shown in Figure 5, an energy absorption section 50 is provided between the metal tube 46 (or a movable plate 44) and the upper frame 24. The energy absorption section 50, the movable plate 44, and the metal tube 46 together constitute a force limiting mechanism 40. The energy absorption section 50 is configured to operate when the head of the occupant P is restrained (Ph) and the forward load (tensile load) applied to the airbag body 32 exceeds a predetermined threshold (when the predetermined load G2 shown in Figure 8 is reached). While absorbing energy with a fixed load (a lower load G3 compared to load G2), it allows the movable plate 44 and the metal tube 46 to rotate forward.

[0056] That is, as shown in Figures 5 to 6B, the energy absorption section 50 is configured to include a metal strip plate 52 and a roller section 54 (described later) for the plate 52 to be wound. The plate 52 is conveyed to the forward side while being plastically deformed (processed) using the roller section 54, thereby absorbing energy at a fixed value.

[0057] When the plate 52 is rolled into a cylindrical shape (not shown), it is supported on the lower frame (not shown), which is one of the seat back frame frames, in a way that allows it to be unrolled. After the free end 52A of the plate 52 is wound around the roller part 54, it is mounted on the outer peripheral surface of the metal tube 46 by screws or the like and is fixed (see Figure 5).

[0058] The roller section 54 is supported on the upper frame 24 and has three rollers arranged sequentially from the front side at predetermined intervals: a front roller 54F, a central roller 54C, and a rear roller 54B. After the free end 52A of the plate 52 is wound around the rear roller 54B, it passes through the gap between the rear roller 54B and the central roller 54C and is wound around the central roller 54C, and further passes through the gap between the central roller 54C and the front roller 54F and is wound around the front roller 54F.

[0059] Furthermore, in normal conditions (before being extended forward), the thickness of the plastic deformation region of the portion of plate 52 that is wound around roller 54 is set to be thicker than the thickness of other plastic deformation regions (see Figure 6B). This configuration ensures that the force limiting mechanism 40 is inactive under forward-facing loads (represented as the tensile load G1 in Figure 8) during the expansion and deployment of the airbag body 32.

[0060] In other words, under the forward-facing load (tensile load) when the airbag body 32 expands and deploys, the plate 52 will become unable to pass through the roller portion 54, or will be very difficult to pass through. As a result, the plate 52 will not be delivered forward. In other words, the plate 52 will be able to withstand the forward-facing load (tensile load) when the airbag body 32 expands and deploys (withstand without moving).

[0061] Next, the function of the airbag device 30 according to the first embodiment that adopts the above structure will be explained.

[0062] When the detection device detects a frontal collision, the inflation device 28 activates, instantly injecting gas into the airbag body 32. As the gas is injected into the airbag body 32, the shell portion 20 ruptures due to the deployment of the airbag body 32 (by being pressed from the inside by the airbag body 32).

[0063] Furthermore, the airbag body 32 extends from the housing portion 20 through the left side of the occupant P's head Ph (the gap between the head Ph of the occupant P on the side window glass side and the head of the occupant on the center seat side, not shown) and deploys forward. That is, when the front and rear chambers 34 expand and are positioned on the left side of the occupant P's head Ph, gas flows from the front end of the front and rear chambers 34 into the top chamber 36, causing the top chamber 36 to expand inward in the seat width direction.

[0064] Furthermore, the fully deployed airbag body 32 (front and rear chambers 34 and top chamber 36) restrains at least the head Ph of the occupant P seated on the vehicle seat 10. That is, the airbag body 32 (front and rear chambers 34 and top chamber 36) can suppress the forward movement of at least the head Ph of the occupant P due to inertial forces.

[0065] Here, the rear end of the airbag body 32 and the side frame 22 are connected together by a force limiting mechanism 40. When the force limiting mechanism 40 restrains the head Ph of the occupant P, if the load (tensile load) applied to the airbag body 32 toward the front exceeds a predetermined threshold (when the predetermined load G2 shown in FIG8 is reached), it will move the airbag body 32 toward the front as shown in FIG7.

[0066] Specifically, by causing the plate 52 constituting the energy absorption section 50 to undergo plastic deformation in a manner that reduces its thickness as it passes through the roller section 54 (while being processed), the movable plate 44 and the metal tube 46 are allowed to rotate forward while absorbing energy at a fixed value. That is, the movable plate 44 and the metal tube 46 rotate (move) forward together with the airbag body 32.

[0067] Therefore, when the head of occupant P is restrained, the amount of forward movement of occupant P's head Ph is relatively small compared to the amount of forward movement of occupant P's chest determined by the restraint force of the seat belt. In other words, the forward travel (movement) of occupant P's head Ph is longer, thereby reducing the rearward load acting on occupant P's head Ph. This effectively suppresses backward tilting of occupant P's neck.

[0068] Furthermore, the force limiting mechanism 40 is set to a non-operating state under the load (tensile load shown as load G1 in FIG. 8) on the forward side when the airbag body 32 expands and deploys. That is, by setting the thickness of the plastic deformation region of a portion of the plate 52 that absorbs energy by utilizing plastic deformation (the portion wound on the roller portion 54) to be thicker than the thickness of other plastic deformation regions, it is able to withstand the load (tensile load) on the forward side when the airbag body 32 expands and deploys.

[0069] Therefore, compared to the case where the force limiting mechanism 40 operates under a forward-facing load (tensile load) during the expansion and deployment of the airbag body 32, the head Ph of the occupant P can be restrained more effectively. Moreover, compared to the case where a method other than setting the thickness in the plastic deformation region of the plate 52 is used to withstand the forward-facing load during the expansion and deployment of the airbag body 32, the structure of the energy absorption section 50 can be simplified.

[0070] Figure 8 illustrates the load-displacement characteristics (FS characteristics) of the airbag body 32 when the occupant P's head is restrained; specifically, it shows the relationship between the load acting on the plate 52 and the amount of head movement of the occupant P. As shown in Figure 8, under the load G1 acting on the plate 52 during the expansion and deployment of the airbag body 32, the amount of head movement of the occupant P is small. That is, the force restraint mechanism 40 does not operate.

[0071] Subsequently, when the head restraint is achieved by the airbag body 32 and a predetermined load G2 is reached (exceeding a predetermined threshold), the force limiting mechanism 40 (energy absorption part 50) operates, thereby suppressing the load acting on the head Ph of the occupant P (acting on the plate 52) to be lower than the load G2, and enabling the head Ph of the occupant P to travel (move) for a longer period of time with this fixed load.

[0072] (Modified example)

[0073] Furthermore, under the forward-facing load (represented as the tensile load G1 in FIG8) during the inflation and deployment of the airbag body 32, the force limiting mechanism 40 can be configured to be in a non-operating state, for example, as shown in FIG9 and FIG10. That is, the force limiting mechanism 40 can also be configured to include an actuator 60, which activates the force limiting mechanism 40 at a precise time when the occupant P's head is restrained and a predetermined load G2 is reached (exceeding a predetermined threshold).

[0074] To be more specific, the actuator 60 is located on the upper side of the side frame 22, and within a hollow cylindrical housing 62 that appears circular when viewed from the side, it has a coil spring 66 as a force-applying component, and a locking portion 64 that protrudes outward (to the left) in the width direction of the seat due to the force applied by the coil spring 66. When viewed from above, the locking portion 64 is roughly T-shaped, and it has a disc portion 64A and a cylindrical portion 64B integrally formed at the axial center of the disc portion 64A.

[0075] On the outer wall portion 62A of the housing 62 in the seat width direction, a circular through hole 62B with a larger inner diameter than the outer diameter of the cylindrical portion 64B is formed. The cylindrical portion 64B protrudes outward in the seat width direction through this through hole 62B. In addition, the engaging portion 64 limits the amount of protrusion of the cylindrical portion 64B from the outer wall portion 62A by interfering (contacting) with the stop portion 63 which is provided on the inner surface of the peripheral wall 62C of the housing 62.

[0076] Furthermore, a miniature gas generator (MGG) 68 is inserted into the through hole 62D on the peripheral wall 62C located between the disc portion 64A (stop portion 63) and the outer wall portion 62A of the engaging portion 64, thereby configuring it to eject gas into the space between the disc portion 64A and the outer wall portion 62A of the engaging portion 64. In other words, by ejecting gas from the miniature gas generator 68, the engaging portion 64 overcomes the force of the coil spring 66 and moves inward in the seat width direction, thereby pulling the cylindrical portion 64B into the housing 62.

[0077] On the other hand, a cylindrical annular portion 48 is embedded and fixed in the metal tube 46, and a rectangular flat flange portion 48A protruding rearward is integrally formed on the outer peripheral surface of the annular portion 48. Moreover, a circular through hole 48B with the same inner diameter as the through hole 62B is formed in the flange portion 48A, extending through the seat width direction, and a cylindrical portion 64B whose protrusion is limited by the stop portion 63 can be inserted into the through hole 48B.

[0078] In other words, the structure is designed to lock the metal tube 46 and the movable plate 44 in a forward-facing manner by inserting the cylindrical portion 64B of the engaging portion 64 into the through hole 48B of the flange portion 48A. Furthermore, the structure is designed to allow the metal tube 46 and the movable plate 44 to rotate forward-facing by ejecting gas from the micro gas generator 68, thereby pulling the cylindrical portion 64B into the housing 62 and disengaging it from the through hole 48B.

[0079] According to the actuator 60 with this structure, the force limiting mechanism 40 can be deactivated under the forward-facing load (tensile load) during the expansion and deployment of the airbag body 32, and can be activated by ejecting gas from the miniature gas generator 68 at the precise timing when the occupant P's head is restrained and a predetermined load G2 is reached (exceeding a predetermined threshold). Therefore, the force limiting mechanism 40 can be activated more reliably than by using methods other than the actuator 60.

[0080] <Second Implementation>

[0081] Next, the airbag device 30 according to the second embodiment will be described. Furthermore, the same symbols will be used for parts equivalent to those in the first embodiment described above, and detailed descriptions will be omitted where appropriate.

[0082] As shown in Figures 11 and 12, the airbag device 30 according to the second embodiment differs from the first embodiment only in that it has a force limiting mechanism 70, which is different from the force limiting mechanism 40. In the force limiting mechanism 70 according to the second embodiment, the movable plate 44 is not provided, and the inflation device 28 is directly fixed to the outer surface of the side frame 22.

[0083] That is, a portion of the outer peripheral surface of the inflation device 28 is integrally mounted on the outer surface of the side frame 22 via a bracket 23 or the like, such that its axial portion faces vertically. Furthermore, the lower end of a metal tube 72, which serves as a supply tube, is embedded in the nozzle 28A, which is the upper end of the inflation device 28. This metal tube 72 constitutes a force limiting mechanism 70, and the rear end of the airbag body 32 is mounted at the upper end of the metal tube 72.

[0084] In other words, the metal tube 72 is fixed to the side frame 22 via the inflation device 28 and can supply gas ejected from the inflation device 28 to the airbag body 32 mounted at its upper end. Furthermore, a flexible hose 74 is provided on the outer periphery of the metal tube 72; the flexible hose 74 is a long hose that connects the upper end of the inflation device 28 and the rear end of the airbag body 32. In other words, the metal tube 72 is housed inside the flexible hose 74.

[0085] Furthermore, the rear end of the airbag body 32 and the side frame 22 are connected together by the metal tube 72 and the hose 74 that constitute the force limiting mechanism 70. In addition, as described later, when the airbag body 32 moves forward, the rear end of the airbag body 32 detaches from the upper end of the metal tube 72.

[0086] That is, the upper end of the metal tube 72 is configured such that when the load (tensile load) applied to the airbag body 32 facing forward exceeds a predetermined threshold, it will detach from the rear end of the airbag body 32. Furthermore, at this time, the middle portion of the hose 74 becomes a structure supported by a cylindrical guide portion 78 (bent into a roughly ">" shape), which is axially positioned on the upper frame 24, etc., in the seat width direction.

[0087] Furthermore, a flat reaction plate 76 is installed at the rear end of the airbag body 32. Moreover, an energy absorption section 56 is provided between the reaction plate 76 and the side frame 22 (or the lower frame not shown), and the energy absorption section 56, together with the metal tube 72, the hose 74 and the reaction plate 76, constitutes the force limiting mechanism 70.

[0088] The energy absorption unit 56 is configured to operate when the load (tensile load) applied to the front side of the airbag body 32 exceeds a predetermined threshold (when the predetermined load G2 shown in FIG8 is reached) during head restraint of the occupant P's head Ph. While absorbing energy with a fixed load (a lower load G3 compared to load G2), it allows the reaction plate 76 (airbag body 32) to move forward.

[0089] That is, the energy absorption section 56 is constructed in the same manner as the energy absorption section 50 in the first embodiment, and it is constructed in such a manner that it includes a plate 52 and a roller section 58 for the plate 52 to be wound. In other words, the only difference between the energy absorption section 56 and the energy absorption section 50 in the first embodiment is the structure of the roller section 58.

[0090] To be more specific, the roller portion 58 is supported within the housing portion 20 that houses the upper ends of the airbag body 32, the metal tube 72, and the hose 74, and has five rollers from the upper front side: a first roller 58A, a second roller 58B, a third roller 58C, a fourth roller 58D, and a fifth roller 58E located below it.

[0091] Furthermore, after the free end 52A of plate 52 (refer to Figures 5 to 6B) is wound around the fifth roller 58E from the rear, it is wound around the fourth roller 58D from the front, then wound around the third roller 58C from the rear, and finally passes through the gap between the second roller 58B and the first roller 58A and is fixed to the reaction plate 76.

[0092] Furthermore, in normal conditions (before being extended forward), the portion of plate 52 that is wound around the roller portion 58 has a thicker plastic deformation region compared to the thickness of other plastic deformation regions. This configuration ensures that the force limiting mechanism 70 is inactive under forward-facing loads (tensile load shown as load G1 in FIG. 8) during the expansion and deployment of the airbag body 32.

[0093] In other words, under the forward-facing load (tensile load) when the airbag body 32 expands and deploys, the plate 52 becomes unable to pass through the roller portion 58, or very difficult to pass through, and thus, the plate 52 will not be delivered forward. In other words, the plate 52 will be able to withstand the forward-facing load (tensile load) when the airbag body 32 expands and deploys (withstand without moving).

[0094] Next, the function of the airbag device 30 according to the second embodiment employing the above-described structure will be explained. Furthermore, functions common to the first embodiment will be omitted from description as appropriate.

[0095] When the detection device detects a frontal collision, the inflation device 28 activates, instantly injecting gas into the airbag body 32. As the gas is injected into the airbag body 32, the shell portion 20 ruptures due to the deployment of the airbag body 32 (by being pressed from the inside by the airbag body 32).

[0096] Furthermore, the airbag body 32 extends from the housing portion 20 through the left side of the occupant P's head Ph (the gap between the head Ph of the occupant P on the side window glass side and the head of the occupant on the center seat side, not shown) and deploys forward. That is, when the front and rear chambers 34 expand and are positioned on the left side of the occupant P's head Ph, gas flows from the front end of the front and rear chambers 34 into the top chamber 36, causing the top chamber 36 to expand inward in the seat width direction.

[0097] Furthermore, the fully deployed airbag body 32 (front and rear chambers 34 and top chamber 36) restrains at least the head Ph of the occupant P seated on the vehicle seat 10. That is, the airbag body 32 (front and rear chambers 34 and top chamber 36) can suppress the forward movement of at least the head Ph of the occupant P due to inertial forces.

[0098] Here, the rear end of the airbag body 32 and the side frame 22 are connected together by a force limiting mechanism 70. When the force limiting mechanism 70 restrains the head Ph of the occupant P, it moves the airbag body 32 forward as shown in FIG13 when the load (tensile load) applied to the airbag body 32 in the forward direction exceeds a predetermined threshold (when the predetermined load G2 shown in FIG8 is reached).

[0099] Specifically, by causing the plate 52, which constitutes the energy absorption section 56 shown in FIG11, to undergo plastic deformation in a manner that reduces its thickness as it passes through the roller section 58, while being processed, the reaction plate 76 is allowed to move forward while absorbing energy at a fixed value. That is, the reaction plate 76 moves forward together with the airbag body 32.

[0100] Therefore, when the head of occupant P is restrained, the amount of forward movement of occupant P's head Ph is relatively small compared to the amount of forward movement of occupant P's chest determined by the restraint force of the seat belt. In other words, the forward travel (movement) of occupant P's head Ph is longer, thereby reducing the rearward load acting on occupant P's head Ph. Therefore, backward tilting of occupant P's neck can be effectively suppressed.

[0101] Furthermore, the force limiting mechanism 70 is set to a non-operating state under the load (represented as load G1 in FIG. 8) on the front side when the airbag body 32 expands and deploys. That is, by setting the thickness of the plastic deformation region of a portion of the plate 52 that absorbs energy through plastic deformation (the portion wound around the roller portion 58) to be thicker than the thickness of other plastic deformation regions, it is able to withstand the load (tensile load) on the front side when the airbag body 32 expands and deploys.

[0102] Therefore, compared to the case where the force limiting mechanism 70 operates under the load (tensile load) facing the front side during the expansion and deployment of the airbag body 32, the head Ph of the occupant P can be restrained more effectively. Moreover, compared to the case where a method other than setting the thickness in the plastic deformation region of the plate 52 is used to bear the load facing the front side during the expansion and deployment of the airbag body 32, the structure of the energy absorption section 56 can be simplified.

[0103] Furthermore, as shown in Figure 13, although the rear end of the airbag body 32 detaches from the upper end of the metal tube 72 when the reaction plate 76 and the airbag body 32 move forward together, the hose 74 extends, thus allowing for a continuous supply of gas to the airbag body 32. Therefore, even if the airbag body 32 moves forward, the head restraint of the occupant P can be effectively maintained. Moreover, since the movable plate 44 in the first embodiment is unnecessary, the structure of the force limiting mechanism 70 can be simplified.

[0104] Although the seat-mounted airbag device 30 of this embodiment has been described above based on the accompanying drawings, the seat-mounted airbag device 30 of this embodiment is not limited to the contents shown in the drawings, and appropriate design changes can be made without departing from the spirit of this disclosure. For example, the supply tube is not limited to a metal tube (metal tube 46 and metal tube 72), and it may also be a resin tube.

[0105] Furthermore, the energy absorption section 50 is not limited to a structure having a plate 52 and a roller section 54, nor is the energy absorption section 56 limited to a structure having a plate 52 and a roller section 58. Although the figures are omitted, the energy absorption sections 50 and 56 can also be configured to include, for example, a torsion bar provided on the retractor. In this case, the structure of the energy absorption sections 50 and 56 can be simplified.

[0106] Symbol Explanation

[0107] 22…Side frame (seat back frame);

[0108] 28…Inflation device;

[0109] 30…Airbag system (seat-mounted airbag system);

[0110] 32…Airbag body;

[0111] 34…anterior and posterior chambers;

[0112] 36…apical chamber;

[0113] 40…force limiting mechanism;

[0114] 44…Modible plate (movable part);

[0115] 46… Metal pipe (supply pipe);

[0116] 50… Energy absorption section;

[0117] 52…board;

[0118] 56…Energy Absorption Section;

[0119] 60…Actuator;

[0120] 70…force limiting mechanism;

[0121] 72… Metal pipe (supply pipe);

[0122] 74… Hose;

[0123] 76...reaction plate;

[0124] P…crew;

[0125] Ph…head.

Claims

1. A seat-mounted airbag device, wherein, The system includes an airbag body comprising front and rear chambers and a top chamber. The front and rear chambers are constructed by gas ejected from an inflation device that operates based on the detection or prediction of a vehicle collision, extending from the side of the occupant's head and towards the front of the seat, and are positioned at the side of the occupant's head. The top chamber extends inward along the width of the seat from the front end of the front and rear chambers and is positioned at the front of the occupant's face. The airbag body and the seat back frame are connected by a force-limiting mechanism that, when restraining the occupant's head, applies force when the airbag body is in use. When the load on the airbag body facing the front of the seat exceeds a predetermined threshold, the airbag body moves towards the front of the seat. The force limiting mechanism has: a movable member including a supply pipe that supplies gas ejected from the inflation device to the airbag body mounted at its upper end, and the lower end being supported on the seat back frame in a manner that allows rotation in the seat width direction as an axial direction; and an energy absorption section disposed between the supply pipe and the seat back frame or between the movable member and the seat back frame, which allows the movable member to rotate towards the front of the seat while absorbing energy when the load exceeds the predetermined threshold.

2. A seat-mounted airbag device, wherein, The system includes an airbag body comprising front and rear chambers and a top chamber. The front and rear chambers are constructed by gas ejected from an inflation device that operates based on the detection or prediction of a vehicle collision, extending from the side of the occupant's head and towards the front of the seat, and are positioned at the side of the occupant's head. The top chamber extends inward along the width of the seat from the front and rear chambers and is positioned at the front of the occupant's face. The airbag body and the seat back frame are connected by a force-limiting mechanism that, when restraining the occupant's head, applies force to the airbag body towards the front of the seat. When the load on the side exceeds a predetermined threshold, the airbag body moves towards the front of the seat. The force limiting mechanism includes: a supply tube connected to the inflation device fixed to the seat back frame to supply gas ejected from the inflation device to the airbag body; a hose that internally houses the supply tube and connects the inflation device and the airbag body, and has excess length; a reaction plate disposed at the rear end of the airbag body on the seat side; and an energy absorption section disposed between the reaction plate and the seat back frame, which, when the load exceeds the predetermined threshold, allows the reaction plate to move towards the front of the seat while absorbing energy.

3. The seat-mounted airbag device as described in claim 1 or 2, wherein, The force limiting mechanism is configured to be in a non-operating state under loads on the front side of the seat when the airbag body inflates and deploys.

4. The seat-mounted airbag device as described in claim 3, wherein, The energy-absorbing part includes a plate that absorbs energy by undergoing plastic deformation. The thickness of a portion of the deformed area of ​​the plate is set to be thicker than the thickness of other deformed areas in order to withstand the load facing the front of the seat when the airbag body expands and deploys.

5. The seat-mounted airbag device as described in claim 3, wherein, The force limiting mechanism is configured to include an actuator that activates the force limiting mechanism when the load exceeds a predetermined threshold.

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