Occupant protection device

Abstract

To provide an occupant protection device that is configured so that a bag main body part being inflated can be restricted from floating from a conducting pipe part, so as to improve performance in protecting an occupant.SOLUTION: In an occupant protection device 10, an airbag 29 is folded back and then stored in a lap belt part 13 of a seat belt 11. The air bag, completely inflated, comprises a bag main body part 30 that can receive an occupant MP and a conducting pipe part 45 through which gas G for inflation is supplied to the bag main body part. In the airbag is arranged a regulating tether 55 that can regulate a separation-side wall part 35R separated from the conducting pipe part in the bag main body completely inflated from floating from an end part 46a of a root part 46 of the conducting pipe part when gas for inflation is initially flown in, while connecting the separation-side wall part 35R to the end part 46a.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to an occupant protection device for protecting an occupant seated on a seat.

Background Art

[0002] Conventionally, as an occupant protection device, an airbag is folded and disposed at a portion of the lap belt portion of a seat belt. When it operates, it inflows with inflation gas and expands to receive and protect the upper body of a forward-moving occupant (see, for example, Patent Document 1). The airbag has, when inflation is completed, a support surface on the lower surface side that is supported by the occupant's thigh, and a bag body portion on the rear surface side that can receive the occupant as an occupant restraint surface, and a conduit portion that supplies inflation gas from a gas supply device to the bag body portion. The conduit portion extends to the fixed end side of the lower end side of the seat belt, has a tip portion connected to the gas supply device, and is connected to the rear end side of the lower surface of the bag body portion when inflation is completed, and communicates a communication port for supplying inflation gas from the gas supply device to the bag body portion with a gas supply port provided in the bag body portion, and a cylindrical intermediate portion between the tip portion and the base portion. And the airbag was assembled to the bag storage part of the lap belt part with the bag body part folded and together with the base part side of the conduit part.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in conventional occupant protection devices, during operation, the inflation gas flows from the tip side of the conduit portion through the intermediate portion to the base portion, and then flows from the communication port of the base portion through the inlet port into the bag main body portion. Therefore, the inflation gas flowing into the bag main body portion hits the side wall portion on the side away from the conduit portion in the bag main body portion and then flows toward the front wall portion side, causing the edge side away from the conduit portion to lift from the base portion of the conduit portion and move away from the upper body of the occupant. That is, since there is a risk that the edge side of the occupant restraint surface of the bag main body portion away from the conduit portion will move away from the upper body of the occupant, it is preferable to restrict the lifting of the bag main body portion from the conduit portion during inflation in terms of improving the protection performance of the occupant.

[0005] The present invention solves the above problems, and an object thereof is to provide an occupant protection device capable of restricting the lifting of the bag main body portion from the conduit portion during inflation and improving the protection performance of the occupant.

Means for Solving the Problems

[0006] In the occupant protection device according to the present invention, an airbag capable of receiving and protecting the upper body of the occupant during inflation is folded and stored in the lap belt portion of a seat belt worn on the waist of an occupant sitting on the seat. When the inflation of the airbag is completed, the airbag includes a bag main body portion having a support surface on the lower surface side for supporting the thigh portion of the occupant and an occupant restraint surface on the rear surface side for receiving the occupant, and a conduit portion for supplying inflation gas from a gas supply device to the bag main body portion. The conduit portion includes a tip portion extending to the fixed end side at the lower end side of the seat belt and connected to the gas supply device, a base portion connected to the rear end side of the lower surface of the bag main body portion when inflation is completed and communicating a communication port for supplying inflation gas from the gas supply device to the bag main body portion with an inlet port provided in the bag main body portion, and a cylindrical intermediate portion between the tip portion and the base portion. The occupant protection device is configured such that the folded bag main body portion is assembled together with the base portion side of the conduit portion to a bag storage portion of the lap belt portion. A regulating tether is disposed that connects a side wall portion of the bag body portion on the side away from the conduit portion at the time of inflation completion to an end portion side of the base portion of the conduit portion away from the intermediate portion, and that can regulate the upward floating from the end portion side on the side wall portion side at the initial stage of the inflow of the inflation gas.

[0007] In the occupant protection device according to the present invention, when the occupant wears a seat belt and the lap belt portion is disposed in front of the waist and is actuated, the inflation gas from the gas generator flowing in from the tip portion of the conduit portion flows into the base portion through the intermediate portion of the conduit portion, flows into the bag body portion from the communication port through the inlet port, and the bag body portion expands and protrudes from the bag storage portion of the lap belt portion. At that time, the bag body portion hits the side wall portion (referred to as the separated side wall portion) on the side away from the conduit portion by the inflowing inflation gas and flows toward the front wall portion side, causing the edge side away from the conduit portion to float upward from the base portion of the conduit portion and move away from the upper body of the occupant. However, since the upward floating of the separated side wall portion from the base portion side of the conduit portion at the initial stage of the inflow of the inflation gas is regulated by the regulating tether, the edge side away from the conduit portion side on the occupant restraint surface is prevented from separating from the upper body of the occupant, and the occupant is received and protected by the occupant restraint surface that is suppressed from separating from the occupant while the support surface is supported on the thigh portion.

[0008] Therefore, in the occupant protection device according to the present invention, the upward floating of the bag body portion from the conduit portion during inflation is regulated, and the protection performance of the occupant can be improved.

[0009] And in the occupant protection device according to the present invention, it is desirable that a second regulating tether is disposed that connects a side wall portion on the conduit portion side that faces the side wall portion on the side away from the conduit portion in the bag body portion at the time of inflation completion in the left-right direction to a portion on the intermediate portion side of the base portion of the conduit portion and that can regulate the upward floating from the portion on the intermediate portion side on the side wall portion side on the conduit portion side at the time of the inflow of the inflation gas.

[0010] In such a configuration, when the bag body portion expands, the first restricting tether on the side away from the conduit portion restricts the separation of the separated side wall portion of the bag body portion from the conduit portion, and the second restricting tether can restrict the separation of the side wall portion (the proximity side wall portion approaching the conduit portion) facing the separated side wall portion in the left - right direction from the conduit portion. That is, since the second restricting tether can restrict the separation of the conduit portion from the proximity side wall portion side of the bag body portion, the first and second restricting tethers can restrict the left - right swinging of the bag body portion during expansion, and can quickly stabilize the posture of the bag body portion at the end of expansion without swinging, thereby protecting the occupant.

[0011] In this case, it is desirable that the second restricting tether is arranged with a longer length dimension than the first restricting tether that connects the side wall portion on the side away from the conduit portion in the bag body portion and the end portion side away from the intermediate portion in the base portion of the conduit portion.

[0012] In such a configuration, it is suitable when the occupant wearing the seat belt is a large - framed occupant. That is, when a large - framed occupant wears a seat belt, since the waist of the large - framed occupant is thick, the length dimension from the fixed end of the portion of the lap belt to the tongue becomes long, and the bag storage portion of the lap belt portion is displaced from the center in the left - right direction of the occupant to the fixed - end side of the seat belt. When the bag body portion expands in this state, if the length dimension of the second restricting tether is the same as the length dimension of the first restricting tether, the bag body portion will protrude from the center side of the thick waist of the occupant toward the front side of the fixed - end side in the left - right direction in the state of being displaced to the fixed - end side of the seat belt, and the occupant restraint surface will be shifted from the front of the upper body of the large - framed occupant in the direction of the fixed - end side in the left - right direction. At this time, if the second restricting tether has a longer length dimension, the direction of the protruding bag body portion can be changed so as to follow the front side in the front - rear direction from the base portion side of the conduit portion to correct the displacement in the direction of the fixed - end side in the left - right direction, and it becomes possible to arrange the occupant restraint surface so as to face the upper body of the large - framed occupant in the front - rear direction on the front side of the upper body of the large - framed occupant, and the forward - moving large - framed occupant can be received and protected with good protection performance by the occupant restraint surface arranged to face the occupant.

[0013] Incidentally, in this case, for a small-sized occupant, when the small-sized occupant wears the seat belt, since the waist of the small-sized occupant is thinner and smaller than that of the large-sized occupant, the length dimension from the fixed end to the tongue of the part of the lap belt portion becomes shorter, and the bag storage portion of the lap belt portion shifts from the center in the left-right direction of the occupant to the tongue side. However, since the waist of the small-sized occupant is thin, the arc-shaped protruding state of the worn lap belt portion becomes gentler (the curvature becomes smaller) compared to the large-sized occupant. Even if the protruding direction of the airbag main body portion is shifted to the tongue side, the shift of the airbag main body portion itself in the left-right direction is small, and it can be stably protected on the occupant restraint surface. Even if the length dimension of the second regulation tether is made longer than the length dimension of the first regulation tether, it is unlikely to cause problems.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Mode for Carrying Out the Invention

[0015] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The occupant protection device 10 of the embodiment is mounted on the seat 1 of a vehicle as shown in FIGS. 1 to 4, and includes a seat belt 11, an airbag 29, and an inflater 24 as a gas supply device for supplying inflation gas to the airbag 29. The seat 1 includes a backrest portion 2 and a seat portion 5.

[0016] The seat belt 11 can be drawn out from a retractor 15 disposed inside the left edge 3a side at the upper end 3 of the backrest portion 2 on one side (the left side in the embodiment) in the left-right direction of the seat 1 so as to restrain an occupant MP seated on the seat 1, and the lower end 11b side is disposed as a fixed end fixed to an anchor member 16 disposed on the left side portion 6 side of the seat portion 5.

[0017] In the middle part of the seat belt 11, a tongue 18 is provided, and the tongue 18 is to be fastened to a buckle 17 disposed on the right side portion 7 of the seat portion 5 on the other side (the right side in the embodiment) in the left - right direction of the seat 1. The seat belt 11 in a state where the tongue 18 is fastened to the buckle 17 has a portion extending from the tongue 18 toward the retractor 15 side as a shoulder belt portion 12 disposed on the front side of the upper body MU of the occupant MP, and a portion extending from the tongue 18 toward the fixed end 11b side as a lap belt portion 13 disposed on the front side of the waist MW of the occupant MP. Note that a release button (not shown) is provided on the buckle 17, and when releasing the fastened tongue 18, by pressing the release button, the tongue 18 can be removed from the buckle 17. Further, the retractor 15 is configured to be provided with a pretensioner that stops the pulling - out if there is a sudden pulling - out of the seat belt 11, and further winds up the pulled - out belt 11 if there is a collision of the vehicle or the like.

[0018] An inflater 24 as a gas supply device includes a substantially cylindrical inflater body 25 that discharges inflation gas, and a pipe portion 26 that protrudes from the inflater body 25 and is bent in a substantially L - shape. The inflater 24 is attached and fixed to the rear side of the left side portion 6 of the seat portion 5 where the retractor 15 is disposed (see FIGS. 1 and 2). The tip end portion 48 side of a conduit portion 45 (described later) of the airbag 29 is externally fitted to the pipe portion 26 and is further clamped by a clamp 27 and connected.

[0019] As shown in FIG. 4, the airbag 29 includes a bag main body portion 30 that inflows inflation gas and greatly expands, a conduit portion 45 that communicates with the lower end 30a side of the bag main body portion 30 and supplies inflation gas from an inflater 24 as a gas supply device to the bag main body portion 30, and first and second restraint tethers 55, 57 that connect the conduit portion 45 and the bag main body portion 30. The bag main body portion 30, the conduit portion 45, and the first and second restraint tethers 55, 57 are formed of a flexible woven fabric such as polyester.

[0020] The bag main body 30 is configured such that when inflation is complete, the peripheral wall 31 expands into a substantially triangular prism shape when viewed from the side (see FIGS. 7 and 8), and includes a bottom wall portion 32 on the bottom side, a rear wall portion 33 on the rear side, a front wall portion 34 on the front side, and left and right side wall portions 35 (L, R). And when inflation is complete, the bag main body 30 uses the lower surface 32a of the bottom wall portion 32 as a support surface 37 to be supported by the thigh portion MF of the occupant MP, and uses the rear surface 33a side of the rear wall portion 33 as an occupant restraint surface 38 to receive the upper body MU of the forward-moving occupant MP.

[0021] Near the rear edge 32b of the bottom wall portion 32, an inlet portion 40 is provided with a plurality (two in the embodiment arranged side by side left and right) of inlets 40a for inflow of inflation gas from the conduit portion 45. Further, vent holes 43 for exhausting the excess of the inflation gas flowing into the bag main body 30 are opened on the front side portions of the left and right side wall portions 35L and 35R. A tack portion 33b is formed on the rear wall portion 33 so as to narrow the vertical dimension, and when inflation of the bag main body 30 is complete, the upper end 33c side of the rear wall portion 33 is configured to approach the head MH of the occupant MP (see FIGS. 7 and 8).

[0022] As shown in FIG. 5, the peripheral wall 31 of the bag main body 30 is formed by sewing two sheet materials, a front side portion 31a and a rear side portion 31b. The front side portion 31a is configured to include a region of the front wall portion 34 and the front side portions of the left and right side wall portions 35 (L, R), and the rear side portion 31b is configured to include a region of the rear wall portion 33, the bottom wall portion 32, and the rear side portions of the side wall portions 35 (L, R).

[0023] The conduit portion 45 connects the base portion 46 to the inlet portion 40 for inflow of inflation gas in the bag main body portion 30 of the airbag 29, and connects the tip portion 48 to the pipe portion 26 of the inflator 24. The base portion 46 is wide, and the portion between the tip portion 48 and the base portion 46 is formed as a cylindrical intermediate portion 49 having the same width dimension as that of the tip portion 48. This conduit portion 45 is formed by sewing the outer peripheral edges of an outer member 50 and a bag side member 51 having the same outer shape (see FIG. 5). A communication port 47 communicating with the inlet 40a of the inlet portion 40 of the bag main body portion 30 is provided in the base portion 46 of the conduit portion 45, and the peripheral edge of the communication port 47 is sewn to the peripheral edge of the inlet 40a, so that the conduit portion 45 is connected to the rear edge 32b side of the bottom wall portion 32 that becomes the lower end 30a of the bag main body portion 30. As described above, the tip portion 48 of the conduit portion 45 is connected to the pipe portion 26 of the inflator 24, and is configured to supply inflation gas from the inflator main body 25 to the bag main body portion 30. Further, the conduit portion 45 has a portion of the outer member 50 away from the bag main body portion 30 in the base portion 46 as a connecting portion 46c, which is sewn to the bag storage portion 22 of the lap belt portion 13.

[0024] Note that, as described above, the conduit portion 45 is formed by sewing the outer peripheral edges of the outer member 50 on the lower surface side having the same outer dimensions and the bag side member 51 on the bag main body portion 30 side. Before sewing the outer peripheral edges of the outer member 50 and the bag side member 51 to each other, the peripheral edge of the communication port 47 of the bag side member 51 is sewn to the peripheral edge of the inlet 40a of the bag main body portion 30, and the connecting portion 46c of the outer member 50 is sewn to the bag storage portion 22 of the lap belt portion 13.

[0025] The first restraint tether 55 connects the right side wall portion on the side away from the conduit portion 45 in the bag main body portion 30 at the time of completion of inflation, that is, the separated side wall portion 35R, and the tip side end portion 46a away from the intermediate portion 49 in the base portion 46 of the conduit portion 45. The length dimension L1 of the first restraint tether 55 is such that the first restraint tether 55 can restrict the upward movement from the tip side end portion 46a side on the separated side wall portion 35R side at the initial stage of inflow of inflation gas.

[0026] The second regulation tether 57 connects the left side wall portion on the conduit portion 45 side, which faces the side wall portion 35R on the side away from the conduit portion 45 in the bag main body portion 30 at the end of inflation in the left-right direction, that is, the proximity side wall portion 35L close to the conduit portion 45, and the base end side end portion 46b on the intermediate portion 49 side in the base portion 46 of the conduit portion 45. The length dimension L2 of the second regulation tether 57 is such that the second regulation tether 57 can regulate the lifting from the portion on the intermediate portion 49 side on the proximity side wall portion 35L side on the conduit portion 45 side when the inflation gas flows in. Also, the length dimension L2 of the second regulation tether 57 is set to be about 1.5 to 2.5 times (about 2.1 times in the embodiment) the length dimension L1 of the first regulation tether 55. In the case of the embodiment, the length dimension L2 of the second regulation tether 57, that is, the substantial length dimension L2 between the base portion 57a connected to the base end side end portion 46b of the base portion 46 and the tip portion 57b connected to the proximity side wall portion 55L is about 135 mm, and the length dimension L1 of the first regulation tether 55, that is, the substantial length dimension L1 between the base portion 55a connected to the tip side end portion 46a of the base portion 46 and the tip portion 55b connected to the separation side wall portion 55R is about 65 mm.

[0027] Note that the tip portions 55b and 57b of the first regulation tether 55 and the second regulation tether 57 are connected to the same symmetric positions with respect to the left and right side wall portions 35L and 35R of the bag main body portion 55 at the end of inflation (see FIG. 5).

[0028] In the occupant protection device 10 of the embodiment, the bag-side member 51 of the conduit portion 45 is connected to the bag main body portion 30 when the peripheral wall 31 is formed, and the tip portions 55b and 57b of the tethers 55 and 57 are connected, and the base portions 55a and 57a of the tethers 55 and 57 are connected to the bag-side member 51 to fold the bag main body portion 30. Further, the outer member 50 of the conduit portion 45 is sewn to the bag storage portion 22 in the lap belt portion 13 of the seat belt 11 in a state where the fixed end 11b at the lower end is not fixed to the anchor member 16 at the connecting portion 46c, and after folding the bag main body portion 30, the outer peripheral edges of the bag-side member 51 and the outer member 50 are sewn to form the conduit portion 45. Then, the folded bag main body portion 30 and the portion of the base portion 46 of the conduit portion 45 are partially wrapped with a belt-like wrapping material (not shown) so as not to collapse, and then the entire bag storage portion 22 of the lap belt portion 13 is covered with the bag cover 60, and the airbag 29 is disposed as the bag assembly 65 in the bag storage portion 22 of the lap belt portion 13.

[0029] Note that the bag cover 60 is formed from a sheet-like cover material 61 that is folded in two (see FIG. 5), wraps the folded bag main body portion 30, etc., and is disposed by sewing the overlapping edges 61a to each other (see FIG. 3).

[0030] Then, in the occupant protection device 10 of the embodiment, after disposing the bag assembly 65 in the bag storage portion 22, while connecting and fixing the fixed end 11b of the seat belt 11 to the anchor member 16, the tip portion 48 of the conduit portion 45 of the airbag 29 is connected to the pipe portion 26 of the inflator 24 using the clamp 27, and then it can be mounted on the seat 1.

[0031] In the occupant protection device 10 of the embodiment, when the occupant MP pulls out the seat belt 11 and fastens the tongue 18 to the buckle 17 so as to wear the seat belt 11, and the lap belt portion 13 is disposed in front of the waist MW and is activated, the inflation gas from the inflator 24 flowing in from the tip 48 of the conduit portion 45 flows into the base portion 46 through the intermediate portion 49 of the conduit portion 45, flows into the bag main body portion 30 from the communication port 47 through the inlet port 40a, and the bag main body portion 30 expands and protrudes from the bag storage portion 22 of the lap belt portion 13, and completes inflation on the front side of the upper body MU of the occupant MP (see FIGS. 6 to 8).

[0032] At this time, the bag main body portion 30 hits the separation side wall portion 35R on the side away from the conduit portion 45 by the inflowing inflation gas G and flows toward the front wall portion 34 side, causing the right edge 34a side away from the conduit portion 45 to lift from the base portion 46 of the conduit portion 45 and move toward the side away from the upper body MU of the occupant MP (see the two-dot chain line in FIG. 9). However, due to the first regulation tether 55 restricting the lifting of the separation side wall portion 35R from the base portion 46 side of the conduit portion 45 at the initial stage of the inflow of the inflation gas G, the right edge 38a side away from the conduit portion 45 on the occupant restraint surface 38 is prevented from separating from the upper body MU of the occupant MP, and the occupant MP is supported by the support surface 37 on the thigh portion MF and is received and protected by the occupant restraint surface 38 that is suppressed from separating from the occupant MP (see FIGS. 6 to 8).

[0033] Therefore, in the occupant protection device 10 of the embodiment, the lifting of the bag main body portion 30 from the conduit portion 45 during inflation is restricted, and the protection performance of the occupant MP can be improved.

[0034] In the occupant protection device 10 of the embodiment, a proximity side wall portion 35L on the conduit portion 45 side that faces the separation side wall portion 35R on the side away from the conduit portion 45 in the bag main body portion 30 at the end of inflation in the left-right direction, and a base end portion 46b on the base side of the intermediate portion 49 side in the base portion 46 of the conduit portion 45 are connected, and a second regulation tether 57 that can regulate the lifting from the portion on the intermediate portion 49 side on the proximity side wall portion 35L side on the conduit portion 45 side when the inflation gas G flows in is disposed.

[0035] Therefore, in the embodiment, when the bag main body portion 30 expands, the first regulation tether 55 on the side away from the conduit portion 45 regulates the separation from the conduit portion 45 in the separation side wall portion 35R of the bag main body portion 30, and the second regulation tether 57 can regulate the separation from the conduit portion 45 in the proximity side wall portion 35L that faces the separation side wall portion 35R in the left-right direction. That is, since the second regulation tether 57 can regulate the separation from the conduit portion 45 on the proximity side wall portion 35L side of the bag main body portion 30, the left and right swinging of the bag main body portion 30 during inflation can be regulated by the first and second regulation tethers 55 and 57, and the posture of the bag main body portion 30 at the end of inflation can be quickly stabilized without swinging, thereby protecting the occupant MP.

[0036] Further, in the embodiment, the length dimension L2 of the second regulation tether 57 is made longer than the length dimension L1 of the first regulation tether 55 that connects the separation side wall portion 35R on the side away from the conduit portion 45 in the bag main body portion 30 and the tip end portion 46a side away from the intermediate portion 49 in the base portion 46 of the conduit portion 45 (L1 < L2), and it is disposed.

[0037] Therefore, in the embodiment, it is suitable for an occupant wearing the seat belt 11 to be a large-sized occupant MPL. That is, as shown in FIGS. 10 and 11, when the large-sized occupant MPL wears the seat belt 11, since the waist MW of the large-sized occupant MPL is thick, the length dimension from the fixed end 11b to the tongue 18 of the portion of the lap belt portion 13 becomes long, and the bag storage portion 22 of the lap belt portion 13 is displaced from the center MC in the left-right direction of the occupant MPL to the fixed end 11b side (left side in the embodiment) of the seat belt 11. When the bag main body portion 30 expands in that state, if the length dimension L2 of the second regulating tether 57 is made equal to the length dimension L1 of the first regulating tether 55, the bag main body portion 30 will project from the center side of the thick waist MW of the occupant MPL toward the front side on the fixed end 11b side in the left-right direction in a state of being displaced to the fixed end 11b side of the seat belt 11 (see the two-dot chain line in FIG. 11), and the occupant restraint surface 38 will be displaced from in front of the upper body MU of the large-sized occupant MPL in the direction of the fixed end 11b side in the left-right direction. At this time, if the second regulating tether 57 has a longer length dimension L2, as shown by the solid line in FIG. 11, the orientation of the protruding bag main body portion 30 can be changed so as to follow the front side in the front-rear direction from the base portion 46 side of the conduit portion 45 to correct the displacement in the direction of the fixed end 11b side in the left-right direction, and the occupant restraint surface 38 can be arranged so as to face the upper body MU of the large-sized occupant MPL in the front-rear direction on the front side of the upper body MU of the large-sized occupant MPL, and the forward-moving large-sized occupant MPL can be received and protected with good protection performance by the occupant restraint surface 38 arranged to face it.

[0038] Incidentally, in this case, as shown in FIGS. 12 and 13, in the case of the small-sized occupant MPS, when the small-sized occupant MPS wears the seat belt 11, since the waist MW of the small-sized occupant MPS is thinner and smaller than that of the large-sized occupant MPL, the length dimension from the fixed end 11b to the tongue 18 of the portion of the lap belt portion 13 becomes shorter, and the bag storage portion 22 of the lap belt portion 13 is displaced from the center MC in the left-right direction of the occupant MPS toward the tongue 18 side (right side in the embodiment). However, since the waist MW of the small-sized occupant MPS is thin, the arc-shaped protruding state of the worn lap belt portion 13 becomes gentler (the curvature becomes smaller) compared to the large-sized occupant MPL. As shown in FIG. 13, even if the protruding direction of the bag main body portion 30 is shifted toward the tongue 18 side, the displacement of the bag main body portion 30 itself in the left-right direction is small, and it can be stably protected by the occupant restraint surface 38. Even if the length dimension L2 of the second regulating tether 57 is made longer than the length dimension L1 of the first regulating tether 55, it is less likely to cause problems.

[0039] Regarding the substantial length dimensions L1 and L2 for connecting the conduit portion 45 of the first regulating tether 55 and the second regulating tether 57 to the side wall portions 35 (L, R) so as to regulate the lifting of the bag main body portion 30 from the conduit portion 45, in the embodiment, the length dimension L2 of the second regulating tether 57 is set to about 2.1 times, which is about 1.5 to 2.5 times the length dimension L1 of the first regulating tether 55. However, if the length dimension L2 is too long, it is difficult to deal with the small-sized occupant MPS, and if it is too small, it is difficult to deal with the large-sized occupant MPL. Therefore, the length dimension L2 of the second regulating tether 57 is preferably about 1.5 to 2.5 times, and more preferably about 1.8 to 2.3 times, the length dimension L1 of the first regulating tether 55.

Explanation of Reference Numerals

[0040] 1... Seat, 10... Occupant protection device, 11... Seat belt, 11b... (Fixed end) lower end, 12... Shoulder belt portion, 13... Lap belt portion, 17... Buckle, 18... Tongue, 22... Airbag storage site, 24... (Gas supply device) inflater, 29... Airbag, 30... Airbag main body portion, 32a... Lower surface, 33... Rear wall portion, 33a... Rear surface, 35R... Separation side wall portion, 35L... Proximity side wall portion, 37... Support surface, 38... Occupant restraint surface, 45... Duct portion, 46... Base portion, 46a... Tip side end portion, 46b... Base side end portion, 48... Tip portion, 49... Intermediate portion, 55... First regulation tether, 57... Second regulation tether, G... Inflation gas, L1... (Length dimension of the first regulation tether), L2... (Length dimension of the second regulation tether), MP... Occupant, MPS... Small-sized occupant, MPL... Large-sized occupant, MW... Waist, MF... Thigh portion, MU... Upper body.

Claims

1. An airbag that can receive and protect the upper body of an occupant during inflation is folded and stored in the lap belt portion of a seat belt worn around the waist of an occupant sitting on a seat. When the inflation of the airbag is completed, the lower surface side serves as a support surface that supports the occupant's thighs, and the rear surface side serves as an occupant restraint surface that can receive the occupant, and the airbag includes a bag body portion and a conduit portion that supplies inflation gas from a gas supply device to the bag body portion. The conduit portion includes a tip portion that extends to the fixed end side at the lower end side of the seat belt and is connected to the gas supply device, a base portion that is connected to the rear end side of the lower surface of the bag body portion when inflation is completed and communicates a communication port for supplying inflation gas from the gas supply device to the bag body portion with an inlet provided in the bag body portion, and a cylindrical intermediate portion between the tip portion and the base portion. The folded bag body portion, together with the base portion side of the conduit portion, is configured to be assembled to a bag storage portion of the lap belt portion, and is an occupant protection device. A restricting tether is disposed to connect a side wall portion on the side of the bag body portion away from the conduit portion when inflation is completed and an end portion side of the base portion of the conduit portion away from the intermediate portion, and to restrict the upward movement of the end portion side from the side wall portion side at the initial stage of the inflow of inflation gas.

2. A second restricting tether is disposed to connect a side wall portion on the conduit portion side facing the side wall portion on the side of the bag body portion away from the conduit portion in the left-right direction when inflation is completed and a portion on the intermediate portion side of the base portion of the conduit portion, and to restrict the upward movement of the portion on the intermediate portion side from the side wall portion side on the conduit portion side at the time of the inflow of inflation gas.

3. The second restricting tether is disposed with a longer length dimension than the first restricting tether that connects the side wall portion on the side of the bag body portion away from the conduit portion and the end portion side of the base portion of the conduit portion away from the intermediate portion.

Images