Seat belt arrangement and method of restraining an occupant by means of a seat belt arrangement

Abstract

In a safety belt device, a safety belt includes a widened portion formed as at least a part of the safety belt, a belt-shaped widened portion that abuts against a passenger's body, deforms from a normal state to be widened in a case where the passenger's body is impacted, a thickness of the widened portion in a widened state where the widened portion is widened is not greater than a thickness of the widened portion in a normal state before the widened portion is widened, and a cross-sectional area of a connecting portion between the widened portion in the widened state and a portion other than the widened portion in the safety belt is at least equal to a cross-sectional area of the connecting portion in the normal state.

Description

Technical Field

[0001] This invention relates to seat belt devices and methods for restraining occupants by means of seat belt devices. Background Technology

[0002] Seat belt devices installed in vehicles such as automobiles are configured to restrain occupants from impact when the vehicle is involved in a collision or other event, thereby protecting the occupants from the impact. Regarding seat belt devices, Patent Document 1 discloses a device in which a front belt portion and a rear belt portion constitute the occupant contact area of ​​the seat belt. In an emergency, by displacing the support blocks supporting the front belt portion and the support blocks supporting the rear belt portion relative to each other in the width direction of the seat belt, the seat belt is widened, thereby dispersing the load acting on the occupant.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2011-156902

[0006] Patent Document 2: Japanese Patent Application Publication No. 2014-223841 Summary of the Invention

[0007] The problem the invention aims to solve

[0008] However, the technology in Patent Document 1 involves a structure where the cross-sectional area of ​​the connection between the first and second support blocks is reduced when the webbing is widened. Therefore, in an emergency, when a large load is applied to the webbing, stress concentrates at this connection, posing a risk of damage to the connection. Therefore, a seatbelt device that can more reliably protect occupants is desired.

[0009] The technology disclosed herein was made in view of the above-mentioned actual situation, and its purpose is to provide a technology that can more reliably protect occupants in a seat belt device.

[0010] Technical solution

[0011] To address the aforementioned problems, the present disclosure employs the following configuration: The present disclosure provides a seatbelt device comprising a seatbelt that restrains an occupant to a seat in a vehicle. The seatbelt is fixed to a fixed object within the vehicle. The seatbelt includes a widening portion, which is at least a part of the seatbelt and is a strip-shaped widening portion that abuts against the occupant's body. Upon impact to the occupant's body, the widening portion deforms from its normal state in a widened manner. The thickness of the widened portion in its widened state is not greater than the thickness of the widened portion in its normal state before widening. Furthermore, the cross-sectional area of ​​the connection between the widened portion in its widened state and other parts of the seatbelt, excluding the widened portion, is at least equal to the cross-sectional area of ​​the connection portion in its normal state.

[0012] This seatbelt device widens the extended section, increasing the contact area with the occupant's body, thereby distributing the load acting on the occupant's body and mitigating the forward leaning of the occupant. This reduces the burden on the occupant's body during an impact, ultimately protecting the occupant from impact damage. Furthermore, since the cross-sectional area of ​​the connection between the widened section and other parts of the seatbelt in the widened state is at least equal to the cross-sectional area of ​​the connection in the normal state, the widened section is widened without compromising the strength of the connection. This helps to prevent damage to the connection.

[0013] In addition, in the seat belt device disclosed herein, the widening portion includes a driver portion, a dielectric elastomer layer of the driver portion and a pair of electrode layers that hold the dielectric elastomer layer are stacked in the thickness direction of the widening portion. In the normal state, the widening portion can also be widened by applying a predetermined voltage to the pair of electrode layers and compressing the dielectric elastomer layer in the thickness direction of the widening portion.

[0014] Alternatively, the seat belt device disclosed herein may also be configured to include: a tongue member inserted into the seat belt; and a buckle member fixed to the vehicle and capable of engaging with the tongue member. The seat belt has a strip-side conductive portion connected to each of the pair of electrode layers in the drive unit. The tongue member has a tongue-side conductive portion configured to contact the strip-side conductive portion of the seat belt into which the tongue member is inserted. Engaging the tongue member with the buckle member thereby restraining the occupant via the seat belt, and a power supply circuit for applying the predetermined voltage to the pair of electrode layers and the tongue-side conductive portion are connected via the buckle member.

[0015] Furthermore, in the seat belt device disclosed herein, the widening portion includes: a sheet member capable of changing its state between a folded state and an unfolded state in the thickness direction of the widening portion; and a state-maintaining member that maintains the state of the sheet member in the folded state in the normal state, and releases the state-maintaining member when a tension exceeding a predetermined size is applied to the seat belt in the normal state, thereby allowing the sheet member to be in the unfolded state, which can also widen the widening portion.

[0016] In addition, in the seat belt device disclosed herein, the sheet member may also be configured to have a restoring force to return to the unfolded state in the folded state.

[0017] Furthermore, in the seat belt device disclosed herein, the widening portion includes: a first movable portion, which includes one end of the widening portion in the extension direction of the seat belt; a second movable portion, which includes the other end of the widening portion and is disposed adjacent to the first movable portion in the width direction of the widening portion; and a connecting member, which connects the first movable portion and the second movable portion. In the normal state, when a tension exceeding a predetermined size is applied to the seat belt, the connecting member rotates in such a way that the first movable portion and the second movable portion are separated from each other in the width direction of the widening portion, thereby widening the widening portion.

[0018] In addition, in the seat belt device disclosed herein, the connecting member is connected to the first movable part via a first rotating shaft extending in the thickness direction of the widened part, and is connected to the second movable part via a second rotating shaft extending in the thickness direction of the widened part. In the normal state, in the extension direction of the widened part, the first rotating shaft may also be located at a position closer to the other end side of the widened part than the second rotating shaft.

[0019] Alternatively, in the seat belt device disclosed herein, the widening portion may also be configured such that by having the occupant lean against the seat belt, the tension of the seat belt is applied, causing it to change from the normal state to the widened state.

[0020] In addition, in the seat belt device disclosed herein, a buffer member may also be provided on at least the widened portion of the seat belt on the surface opposite to the occupant's body.

[0021] Furthermore, the technology disclosed herein can also be specifically defined as a method for restraining an occupant using a seatbelt device. That is, the technology disclosed herein can also be a method for restraining an occupant using a seatbelt device, comprising: forming a widened portion as at least a part of the seatbelt, the widened portion being a strip-shaped widened portion abutting against the occupant's body, deforming from a normal state to a widened state upon impact with the occupant's body; due to the impact, by bringing the occupant's body against the seatbelt, thereby applying tension to the seatbelt including the widened portion, causing the widened portion to be in a widened state, the thickness of the widened portion in the widened state not greater than the thickness of the widened portion in the normal state before widening, and the cross-sectional area of ​​the connection portion between the widened portion in the widened state and other parts of the seatbelt excluding the widened portion being at least equal to the cross-sectional area of ​​the connection portion in the normal state; and making the contact area between the widened portion in the widened state and the occupant's body larger than the contact area in the normal state, thereby dispersing the load acting on the occupant's body.

[0022] Beneficial effects

[0023] According to the technology disclosed herein, occupants can be protected more reliably in seat belt devices. Attached Figure Description

[0024] Figure 1 This is a perspective view of a vehicle seat equipped with the vehicle seat belt device according to Embodiment 1.

[0025] Figure 2 This is a diagram showing the normal state of the widened section.

[0026] Figure 3 This is a diagram showing the widened state of the widened section.

[0027] Figure 4 This is a cross-sectional view of the widened section in its normal state.

[0028] Figure 5 This is a sectional view of the widened portion in its widened state.

[0029] Figure 6 This is a diagram showing the tongue component.

[0030] Figure 7 This diagram shows the connection state between the conductive parts on the tongue side and the widened part inside the sliding hole.

[0031] Figure 8 This diagram shows the normal state of the widened portion of the seat belt device according to Embodiment 2.

[0032] Figure 9 This is a diagram showing the widened state of the widened portion of the seat belt device according to Embodiment 2.

[0033] Figure 10 This is a diagram showing the normal state of the widened portion of the seat belt device according to Variation 1 of Embodiment 2.

[0034] Figure 11 This is a diagram showing the widened state of the widened portion of the seat belt device according to Variation 1 of Embodiment 2.

[0035] Figure 12 This is a diagram showing the normal state of the widened portion of the seat belt device involved in Modification 2 of Embodiment 2.

[0036] Figure 13 This is a plan view showing the normal state of the widened portion of the seat belt device according to Embodiment 3.

[0037] Figure 14 This is a plan view showing the widened state of the widened portion of the seat belt device according to Embodiment 3.

[0038] Figure 15 This is a perspective view showing the normal state of the widened portion of the seat belt device involved in a variation of Embodiment 3.

[0039] Figure 16 This is a perspective view showing the widened state of the widened portion of the seat belt device according to a variation of Embodiment 3. Detailed Implementation

[0040] The embodiments of this disclosure will now be described with reference to the accompanying drawings. It should be noted that each configuration and combination of configurations in each embodiment is an example, and appropriate additions, omissions, substitutions, and other modifications can be made to the configuration without departing from the spirit of the invention. This disclosure is not limited to the embodiments, but only to the claims. Furthermore, the embodiments described below apply the technology of this disclosure to vehicle seatbelt devices, but the application of the technology of this disclosure is not limited to vehicle seatbelt devices. A vehicle is an example of a means of transportation involved in this disclosure, and the technology of this disclosure can also be applied to seatbelt devices in means of transportation other than vehicles.

[0041] <Implementation Method 1>

[0042] Figure 1 This is a perspective view of a vehicle seat S10 equipped with a vehicle seat belt device (hereinafter referred to as seat belt device) 1000 according to Embodiment 1. Unless otherwise specified, the front-back, up-down, and left-right directions in the following description refer to the front-back, up-down, and left-right directions of the vehicle seat S10. Figure 1The arrows in the diagram indicate the front-to-back, up-down, and left-to-right directions of the vehicle seat S10. The seat belt device 1000 is configured such that it is installed in the vehicle seat S10 (an example of a vehicle seat) where the vehicle occupant sits, and in the event of an impact to the occupant's body due to a vehicle collision or emergency braking, the seat belt 100 restrains the occupant to the vehicle seat S10, thereby protecting the occupant from impact.

[0043] [Device Composition]

[0044] like Figure 1 As shown, the seatbelt device 1000 includes a seatbelt 100, a retractor 200, a seatbelt anchor 300, a tongue member 400, a buckle member 500, and a shoulder anchor 600. The seatbelt 100 is formed as a strap and restrains the occupant to the seat of the vehicle. The retractor 200 is located at the lower part of a vehicle pillar (not shown) and, when not in use, winds up one end of the seatbelt 100 to store it. The seatbelt anchor 300 secures the other end of the seatbelt 100 to the seat frame of the vehicle seat S10 (an example of a fixed object). The tongue member 400 is slidably mounted to the seatbelt 100 by inserting it into the seatbelt 100. The buckle member 500 is fixed to the vehicle body and can engage with the tongue member 400. The shoulder anchor 600 is located at the upper part of a vehicle pillar (not shown) and slidably supports the seatbelt 100. The buckle component 500 engages with the tongue component 400, thereby securing the tongue component 400 and restraining the occupant via the seat belt 100. For example, Figure 1 As shown, the seat belt 100 is formed to include a widened portion 10 and a belt portion 20.

[0045] Figure 2 This is a diagram showing the normal state of the widened portion 10 (before the widened state). Figure 3 This diagram shows the widened state of the widened portion 10. In this embodiment, the widened portion 10, when subjected to impact to the occupant's body (as indicated by numeral M1), [reflects / ... Figure 2 The normal state shown is transformed as follows Figure 3 The widened state shown is wider than the normal state, thereby increasing the contact area with the body of occupant M1, dispersing the load acting on the body of occupant M1, and mitigating the forward tilting of the body of occupant M1. This reduces the burden on the body of occupant M1 from the impact.

[0046] like Figure 2As shown, the seat belt 100 is divided by the tongue member 400 into a shoulder strap 110 that restrains the upper body of the occupant M1 and a lap belt 120 that restrains the waist of the occupant M1. The widening portion 10 is formed as a strap as part of the seat belt 100, abutting against the body of the occupant M1. In this embodiment, the widening portion 10 extends from the shoulder strap 110 to the lap belt 120. That is, the widening portion 10 is inserted into the tongue member 400. However, the scope of the widening portion involved in this disclosure is not limited to this. The widening portion can be formed as at least a part of the seat belt, abutting against the occupant's body. For example, the widening portion may be formed as the entire seat belt. Alternatively, the widening portion may be formed only as the shoulder strap. In this design, of the two ends of the widening portion 10 extending in the direction of the seat belt 100, the end on the side of the retractor 200 (i.e., the aforementioned end side of the seat belt 100) is designated as the first end 101, and the end on the side of the seat belt anchor 300 (i.e., the aforementioned other end side of the seat belt 100) is designated as the second end 102. The belt portion 20 is the portion of the seat belt 100 other than the widening portion 10. The belt portion 20 is similar to a typical seat belt, formed of a strip of fabric, and does not have the widening function of the widening portion 10. The first end 101 and the second end 102 of the widening portion 10 are respectively connected to the belt portion 20. Figure 2 The mark C1 indicates the connection between the first end 101 of the widened portion 10 and the belt portion 20, and the mark C2 indicates the connection between the second end 102 of the widened portion 10 and the belt portion 20.

[0047] Figure 4 This is a cross-sectional view of the widened portion 10 in its normal state (before widening). Figure 4 In, it is shown Figure 2 Section AA. That is, in Figure 4 The image shows a cross-section of the widened portion 10, that is, a cross-section perpendicular to the extending direction of the seat belt 100. Additionally, Figure 5 This is a cross-sectional view of the widened portion 10 in its widened state. Figure 4 The designation S1 indicates the front surface of the widened portion 10, and the designation S2 indicates the rear surface of the widened portion 10. The rear surface S2 is the surface opposite to the body of the occupant M1, and it is the surface that abuts against the body of the occupant M1. Furthermore, Figure 4 The arrows in the diagram indicate the width and thickness directions of the widened portion 10.

[0048] like Figure 4 As shown, the widened portion 10 is configured to include a driver portion 1, a side conductive portion 2, and a cover portion 3. The driver portion 1 is configured to realize the widening function of the widened portion 10. The driver portion 1 includes a dielectric elastomer layer 11 and a pair of electrode layers 12 and 13 that hold the dielectric elastomer layer 11, which are formed by stacking them in the thickness direction of the widened portion 10. Figure 4As shown, electrode layer 12 is disposed on the front surface S1 side of the widened portion 10, and electrode layer 13 is disposed on the rear surface S2 side of the widened portion 10.

[0049] The dielectric elastomer layer 11 is formed into a sheet shape from a dielectric polymer that has insulating properties, a high dielectric constant, and is elastically deformable. Examples of dielectric polymers such as acrylic rubber and silicone rubber can be used as materials for the dielectric elastomer layer 11. However, the materials for the dielectric elastomer layer disclosed herein are not limited to these.

[0050] The pair of electrode layers 12 and 13 are conductive, sheet-like electrodes that can stretch and deform according to the elastic deformation of the dielectric elastomer layer 11. The pair of electrode layers 12 and 13 are formed by incorporating a conductive filler into an elastically deformable main material. Examples of such conductive fillers include conductive carbon black, carbon nanotubes, and conductive metal fillers. However, the materials of the electrode layers disclosed herein are not limited to these.

[0051] like Figure 4 As shown, the side conductive portion 2 includes a pair of conductive plates 21 and 22. The pair of conductive plates 21 and 22 are disposed on opposite sides to clamp the driver portion 1 in the width direction of the widened portion 10 and extend in the thickness direction of the widened portion 10. The conductive plate 21 is connected to the side end of the electrode layer 12 in a generally L-shaped manner with the electrode layer 12, and the conductive plate 22 is connected to the side end of the electrode layer 13 in a generally L-shaped manner with the electrode layer 13.

[0052] The cover 3 is a component that covers the driver part 1 and the conductive part 2 with side contact. It is insulating and elastically deformable. The material of the cover 3 is not particularly limited; for example, elastic fabric materials, acrylic rubber, and silicone rubber are examples of suitable resin materials. Figure 4 As shown, the cover portion 3 includes a front surface cover 31, a rear surface cover 32, and a pair of side surface covers 33 and 34. The front surface cover 31 is disposed on the front surface S1 side of the widened portion 10 and covers the electrode layer 12. The rear surface cover 32 is disposed on the rear surface S2 side of the widened portion 10 and covers the electrode layer 13. The pair of side surface covers 33 and 34 are respectively disposed on both sides of the width direction of the widened portion 10 and cover a pair of conductive plates 21 and 22. The side surface cover 33 includes a first side surface cover 331 connected to one end of the front surface cover 31 and a second side surface cover 332 connected to one end of the rear surface cover 32. A portion of the first side surface cover 331 and the second side surface cover 332 overlap each other in the width direction of the widened portion 10. Similarly, the side surface cover 34 includes a first side surface cover 341 connected to the other end of the front surface cover 31 and a second side surface cover 342 connected to the other end of the rear surface cover 32. A portion of the first side surface cover 341 and a portion of the second side surface cover 342 overlap each other in the width direction of the widened portion 10.

[0053] Figure 6 This is a diagram representing the tongue component 400. Figure 6 (A) is a view of the tongue member 400 viewed from the thickness direction of the widened portion 10. Figure 6 (B) is Figure 6 (A) BB section view. For example... Figure 6 As shown in (A), the tongue member 400 includes a base portion 401, a sliding hole 402, a pair of tongue-side conductive portions 403 and 404, and a tongue plate 405. The base portion 401 is a resin component. The sliding hole 402 is formed on the base portion 401, and the sliding hole is a hole for inserting the seat belt 100 (i.e., the widened portion 10). The tongue plate 405 is a metal component connected to the base portion 401 and engaging with the buckle member 500. The pair of tongue-side conductive portions 403 and 404 are conductive wire-like components. Figure 6 The dashed lines in (A) represent a pair of tongue-side conductive portions 403 and 404 inside the base portion 401. For example... Figure 6 (A) and Figure 6 As shown in (B), a pair of tongue-side conductive portions 403 and 404 extend along the side edge of the tongue plate 405, pass through the interior of the base portion 401, and their front ends protrude into the sliding hole 402. Wherein, as Figure 6 As shown in (B), an insulating layer 406 with insulating properties is inserted between the tongue plate 405 and the pair of tongue-side conductive portions 403, 404. Furthermore, in this embodiment, a power supply circuit (not shown) provided in the vehicle and generating a predetermined voltage for operating the drive unit 1 is connected to the buckle member 500. Moreover, the tongue plate 405 of the tongue member 400 engages with the buckle member 500, thereby connecting the power supply circuit and the pair of tongue-side conductive portions 403, 404 via the buckle member 500.

[0054] Figure 7 This diagram shows the connection state between the pair of tongue-side conductive parts 403 and 404 inside the sliding hole 402 and the widened part 10. Figure 7 (A) is a 3D diagram. Figure 7 (B) is Figure 7 (A) CC section view. For example... Figure 7As shown in (B), the tongue-side conductive portion 403 is deformed by rolling up a portion of the first side surface cover 331 and the second side surface cover 332 of the side surface cover 33, thereby inserting between the first side surface cover 331 and the second side surface cover 332 and contacting the conductive plate 21 with the side conductive portion 2. Similarly, the tongue-side conductive portion 404 is deformed by rolling up a portion of the first side surface cover 341 and the second side surface cover 342 of the side surface cover 34, thereby inserting between the first side surface cover 341 and the second side surface cover 342 and contacting the conductive plate 22 with the side conductive portion 2. The tongue-side conductive portion 403 contacts the conductive plate 21 with the side conductive portion 2, and the tongue-side conductive portion 404 contacts the conductive plate 22 with the side conductive portion 2, thereby connecting the power supply circuit and the side conductive portion 2 via the buckle member 500 and the tongue member 400, and is in a state where a predetermined voltage can be applied to a pair of electrode layers 12, 13. When the tongue member 400 slides the widened portion 10, the tongue-side conductive portion 403 slides against the conductive plate 21, and the tongue-side conductive portion 404 slides against the conductive plate 22, thereby maintaining the contact state between the tongue-side conductive portions 403 and 404 and the conductive plates 21 and 22. Furthermore, as described above, since the cover portion 3 is formed to be elastically deformable, in the portion where the pair of tongue-side conductive portions 403 and 404 are not inserted, such as... Figure 4 as well as Figure 5 As shown, the pair of conductive plates 21 and 22 are maintained in a state where a pair of side surface covers 33 and 34 cover the pair of conductive plates 21 and 22, thus maintaining insulation.

[0055] [action]

[0056] The following describes the operation of the widened section 10 from its normal state to its widened state. Figure 2 as well as Figure 4 In the normal state shown, when the ECU detects or anticipates an impact caused by a vehicle collision or an impact caused by emergency deceleration such as emergency braking based on a signal from an impact sensor (not shown), it supplies operating current to the power supply circuit. This applies a predetermined voltage to a pair of electrode layers 12, 13 via the power supply circuit. When the predetermined voltage is applied to the pair of electrode layers 12, 13, static electricity is generated between them. This static electricity causes the electrode layers 12, 13 to attract each other, compressing the dielectric elastomer layer 11 in the thickness direction and elongating it in the planar direction. Thus, as... Figure 3 as well as Figure 5 As shown, the widened portion 10 is wider than in the normal state. As a result, the contact area between the widened portion 10 in the widened state and the body of the occupant M1 is larger than that in the normal state, and the load acting on the body of the occupant M1 is distributed.

[0057] Since the dielectric elastomer layer 11 is compressed in the thickness direction, the thickness of the widened portion 10 in the widened state is less than the thickness of the widened portion 10 in the normal state before widening. Furthermore, since the widened portion 10 is widened by utilizing the operation of the electrostatic actuator 1, the shapes of the connection portions C1 and C2 between the widened portion 10 and the belt portion 20 remain unchanged. Therefore, the cross-sectional area of ​​the connection portion C1 in the widened state is equal to the cross-sectional area of ​​the connection portion C1 in the normal state, and the cross-sectional area of ​​the connection portion C2 in the widened state is equal to the cross-sectional area of ​​the connection portion C2 in the normal state. It should be noted that the "cross-sectional area of ​​the connection portion" referred to here refers to the area of ​​the cross-section of the connection portion perpendicular to the extension direction of the seat belt 100.

[0058] When the voltage applied to the pair of electrode layers 12 and 13 is stopped, the dielectric elastomer layer 11 recovers to its original shape through its own elasticity, thereby restoring the widened portion 10 to its normal state. It should be noted that the operation in this embodiment can also be performed before an emergency deceleration occurs (for example, at a stage where the obstacle detection sensor determines that the vehicle cannot avoid a collision with an obstacle).

[0059] [Function / Effect]

[0060] As described above, the seat belt 100 of the seat belt device 1000 according to this embodiment includes a strip-shaped widening portion 10, which is formed as at least a part of the seat belt 100 and abuts against the body of the occupant M1. Moreover, the widening portion 10 is configured such that when the body of the occupant M1 is impacted, it deforms in a widening manner, thereby changing from a normal state to a widened state.

[0061] With this seatbelt device 1000, the widened portion 10 is widened, increasing the contact area with the occupant M1's body, thereby dispersing the load acting on the occupant M1's body and mitigating the forward tilting of the occupant M1's body. This reduces the burden on the occupant M1's body from impact. As a result, the occupant M1 can be protected from impact.

[0062] Furthermore, since the thickness of the widened portion 10 in the widened state is less than the thickness of the widened portion 10 in the normal state, that is, since the widened portion 10 is thinner in the widened state, the flexibility of the widened portion 10 can be improved. Therefore, the widened portion 10 fits snugly (closes seamlessly) to the body of the occupant M1, increasing the contact area between the widened portion 10 and the body of the occupant M1. This suppresses uneven load distribution on the widened portion 10, reducing the burden on the body of the occupant M1. It should be noted that in the technology disclosed herein, the thickness of the widened portion in the widened state only needs to be no more than the thickness in the normal state, or the thickness of the widened portion in the widened state and the thickness of the widened portion in the normal state can be equal.

[0063] When the seat belt 100 protects the occupant M1 from impact, the occupant M1's body rests against the seat belt 100, thus subjecting the seat belt 100 to a larger load. In this case, assuming the widened portion 10 is in a widened state, causing the cross-sectional area of ​​the connecting portions C1 and C2 to be smaller than its normal cross-sectional area, there is a possibility of reduced strength in the connecting portions C1 and C2. As a result, there is a concern that the connecting portions C1 and C2 may break due to the concentrated load on them. Conversely, in this embodiment, the cross-sectional area of ​​the connecting portions C1 and C2 in the widened state of the widened portion 10 is equal to the cross-sectional area of ​​the connecting portions C1 and C2 in their normal state. Therefore, since the widened portion 10 is in a widened state without a reduction in the strength of the connecting portions C1 and C2, breakage of the connecting portions C1 and C2 can be suppressed. It should be noted that in the technology disclosed herein, the cross-sectional area of ​​the connecting portion in the widened state only needs to be at least equal to the cross-sectional area in its normal state, or the cross-sectional area in the widened state can be larger than the cross-sectional area in its normal state.

[0064] Furthermore, the widened portion 10 according to this embodiment includes a driver portion 1, wherein a dielectric elastomer layer 11 and a pair of electrode layers 12, 13 holding the dielectric elastomer layer are stacked in the thickness direction of the widened portion 10. Moreover, the widened portion 10 is configured such that, under normal conditions, a predetermined voltage is applied to the pair of electrode layers 12, 13, and the dielectric elastomer layer 11 is compressed in the thickness direction of the widened portion 10, thereby widening it. Therefore, since the widened portion 10 is widened by the driver portion 1, it is possible to widen the widened portion 10 without a decrease in the cross-sectional area of ​​the connecting portions C1, C2. It should be noted that the thickness of the widened portion 10 decreases due to its widened state, but at the same time, the widened portion 10 widens, so the cross-sectional area of ​​the widened portion 10 does not decrease significantly. Therefore, there is no need to worry about a reduction in the strength of the widened portion 10 relative to tensile loads due to its widened state.

[0065] Furthermore, the seat belt device 1000 according to this embodiment also includes: a tongue member 400 inserted into the seat belt 100; and a buckle member 500 fixed to the vehicle and capable of engaging with the tongue member 400. Additionally, the seat belt 100 has a belt-side conductive portion 2 (a pair of conductive plates 21, 22) respectively connected to a pair of electrode layers 12, 13 of the driver unit 1. The tongue member 400 has a pair of tongue-side conductive portions 403, 404, which are configured to contact the belt-side conductive portion 2 of the seat belt 100 into which the tongue member 400 is inserted. Moreover, the power supply circuit for applying a predetermined voltage to the pair of electrode layers 12, 13 and the tongue-side conductive portions 403, 404 are configured such that the tongue member 400 is engaged with the buckle member 500, thereby connecting the power supply circuit and the tongue-side conductive portions via the buckle member 500. Thus, applying a predetermined voltage to the pair of electrode layers 12, 13 can drive the driver unit 1.

[0066] <Implementation Method 2>

[0067] The seat belt device according to Embodiment 2 will now be described. Figure 8 This is a diagram showing the normal state of the widened portion 10A of the seat belt device 1000A according to Embodiment 2. Figure 8 (A) is a view of the widened portion 10A from the thickness direction. Figure 8 (B) is Figure 8 (A) DD section view. Figure 9 This is a diagram showing the widened state of the widened portion 10A of the seat belt device 1000A according to Embodiment 2. Figure 9 (A) is a view of the widened portion 10A from the thickness direction. Figure 9 (B) is Figure 9 (A) EE cross-sectional view. Below, in the description of Embodiment 2, [the following will be used in conjunction with...] Figures 1 to 7 The description focuses on the differences of the seat belt device 1000 in Embodiment 1, and omits detailed descriptions of the similarities with the seat belt device 1000.

[0068] like Figure 8 (B) and Figure 9 As shown in (B), the widened portion 10A according to this embodiment includes a sheet member 5 and a state-maintaining member 6. The sheet member 5 can, as Figure 8 As shown, in the thickness direction of the widened portion 10A, the folded state is similar to that shown in the figure. Figure 9 The unfolded state changes between the unfolded states shown. For example... Figure 9As shown in (A), the sheet member 5 is divided into a first region A1, a second region A2, and a third region A3, with a first hinge portion H1 and a second hinge portion H2 extending along the extending direction of the widened portion 10A (the extending direction of the seat belt 100A) as boundaries. The second region A2 is connected to one side of the first region A1 via the first hinge portion H1, and the third region A3 is connected to the other side of the first region A1 via the second hinge portion H2. Figure 8 As shown in (B), in the folded state of the sheet member 5, the second region A2 and the third region A3 coincide with the front surface of the first region A1. Figure 9 As shown in (B), the second region A2 rotates relative to the first region A1 with the first hinge H1 as the axis, and the third region A3 rotates relative to the first region A1 with the second hinge H2 as the axis, opening the first region A1, the second region A2 and the third region A3, thereby changing the sheet member 5 from the folded state to the unfolded state.

[0069] Furthermore, the sheet member 5 includes a main body 51, i.e., a sheet-like fabric member; and ribs 52, which are mounted on the main body 51. The ribs 52 are elastic wires that are straight in their natural state and are formed of a shape memory alloy. Multiple ribs 52 are mounted on the main body 51 extending along the width direction of the widened portion 10A. Therefore, the ribs 52 abut against the main body 51 via the second region A2, the first region A1, and the third region A3. In the folded state, the ribs 52 fold together with the main body 51, thereby applying a restoring force to return to a straight shape to the ribs 52. Thus, the sheet member 5 is formed to have a restoring force to return to its unfolded state in the folded state.

[0070] The state-maintaining member 6 is used to maintain the sheet member 5 in a folded state under normal conditions. The state-maintaining member 6 is configured to release its state-maintaining function when a tension exceeding a predetermined value is applied to the seatbelt 100A under normal conditions. In this embodiment, the state-maintaining member 6 is a surface latch that connects the second region A2 and the third region A3 of the sheet member 5 in the folded state. Due to the tension acting on the seatbelt 100A, the surface latch is disengaged, thereby releasing the connection between the second region A2 and the third region A3 and releasing the state-maintaining function.

[0071] In the normal state of the widened portion 10A, when the occupant M1's body is pressed against the seatbelt 100 due to an impact caused by a vehicle collision or an impact caused by emergency deceleration such as emergency braking, resulting in a tension exceeding a predetermined value acting on the seatbelt 100A, the state maintenance member 6 is released. Then, the restoring force of the rib 52 causes the sheet member 5 to unfold, thereby widening the widened portion 10A. This disperses the load acting on the occupant M1's body and mitigates the forward tilting of the occupant M1's body. As a result, the occupant M1 is protected from impact. Furthermore, since the sheet member 5 changes from a folded state to an unfolded state, the widened portion 10A changes from its normal state to a widened state, and therefore the thickness of the widened portion 10A in the widened state is less than that in the normal state. That is, since the widened portion 10A is thinner in the widened state, the flexibility of the widened portion 10A can be improved, and the contact area between the widened portion 10A and the occupant M1's body can be increased. This reduces the burden on the body of occupant M1. Furthermore, in this embodiment, since the thin sheet member 5 changes from a folded state to an unfolded state, the widened portion 10A is widened. Therefore, the cross-sectional areas of the connecting portions C1 and C2 in the widened state of the widened portion 10A are equal to those in the normal state. Thus, since the widened portion 10A is widened without a decrease in the strength of the connecting portions C1 and C2, damage to the connecting portions C1 and C2 can be suppressed.

[0072] Furthermore, in this embodiment, the widening portion 10A widens from its normal state by applying tension to the seat belt 100A, thereby causing the occupant M1 to rest against it. That is, since the widening portion 10A utilizes the load caused by the occupant to widen, a separate drive source is not required.

[0073] It should be noted that the state-maintaining component of this disclosure is not limited to surface snaps. For example, snaps can be used instead of surface snaps. Additionally, zippers used in zippered resealable bags such as Mipono (registered trademark) can be used instead of surface snaps. Furthermore, the sheet member can be kept in a folded state by stitching, and the state-maintaining function can be released by cutting the stitching under tension applied to the seatbelt. When the stitching is used as the state-maintaining component, it can also be configured such that the sheet member is formed of a stretchable member, and the stitching is cut when the tension applied to the seatbelt causes the sheet member to extend beyond a certain range.

[0074] [Modification of Implementation Method 2]

[0075] The following describes a modified example of the seat belt device according to Embodiment 2. In the description of the modified example, the description will focus on the differences from the seat belt device 1000A, and detailed descriptions of the points that are the same as those in the seat belt device 1000A will be omitted.

[0076] [Modification 1 of Implementation Method 2]

[0077] Figure 10 This is a diagram showing the normal state of the widened portion 10B of the seat belt device 1000B according to a variation of Embodiment 2, Example 1. Figure 11 This diagram shows the widened state of the widened portion 10B of the seat belt device 1000B according to Modification 1 of Embodiment 2. Figure 10 as well as Figure 11 The image shows the state of the widened portion 10B as viewed from its thickness direction.

[0078] like Figure 10 as well as Figure 11 As shown, the widened portion 10B in Modification 1 of this embodiment includes a sheet member 5B and a state-maintaining member 6B. The sheet member 5B can, as shown in the figure, extend the width of the portion 10B. Figure 10 As shown, in the thickness direction of the widened portion 10B, the folded state is similar to that shown in the example. Figure 11 The sheet member 5B is shown changing between its unfolded and unfolded states. It includes a first sheet portion 53 and a second sheet portion 54, which are connected via a hinge portion H3 extending along the extension direction of the widened portion 10B (the extension direction of the seatbelt 100B). The first sheet portion 53 includes a first end portion 101 of the widened portion 10B and is connected to the belt portion 20 via a connecting portion C1. The second sheet portion 54 includes a second end portion 102 of the widened portion 10B and is connected to the belt portion 20 via a connecting portion C2. In the folded state of the sheet member 5B, the second sheet portion 54 overlaps with the front surface of the first sheet portion 53. The second sheet portion 54 rotates relative to the first sheet portion 53 about the hinge portion H3, opening the first sheet portion 53 and the second sheet portion 54, thereby changing the sheet member 5B from the folded state to the unfolded state. The sheet member 5B is formed of a composite fiber consisting of nylon fibers wound around fibers including a superelastic alloy, the fibers including the superelastic alloy being shape-memorized into a straight shape. Therefore, the sheet member 5B is formed to have a restoring force to return to the unfolded state when folded.

[0079] The state-maintaining member 6B in Variation 1 of this embodiment is configured to maintain the sheet member 5B in a folded state under normal conditions, and release the state-maintaining mechanism when a tension exceeding a predetermined value is applied to the seat belt 100B. The state-maintaining member 6B is a zipper used in zippered resealable bags such as Mipono (registered trademark). Multiple state-maintaining members 6B are respectively installed on the first sheet portion 53 and the second sheet portion 54, extending along the width direction of the widened portion 10B. The state-maintaining members 6B of the first sheet portion 53 and the second sheet portion 54 are engaged, thereby connecting the first sheet portion 53 and the second sheet portion 54 of the sheet member 5B in the folded state, thus maintaining the sheet member 5B in the folded state under normal conditions.

[0080] In the seatbelt device 1000B, under normal conditions, when a tension exceeding a predetermined value is applied to the seatbelt 100B, the state-maintaining member 6B is disengaged and engaged, thereby releasing the state-maintaining member 6B. Furthermore, the restoring force sheet member 5B unfolds, thus widening the widening portion 10B. This protects the occupant M1 from impact. The thickness of the widening portion 10B in the widened state is less than that in the normal state, and the cross-sectional areas of the connecting portions C1 and C2 in the widened state are equal to those in the normal state.

[0081] [Modification 2 of Implementation Method 2]

[0082] Figure 12 This diagram shows the normal state of the widened portion 10C of the seatbelt device 1000C according to a variation 2 of Embodiment 2. Figure 12 The cross-section of the widened portion 10C is shown, that is, the cross-section perpendicular to the extension direction of the seat belt 100C.

[0083] like Figure 12 As shown, in the widened portion 10C according to Modification 2 of this embodiment, a buffer member 30 is provided on the surface opposite to the body of the occupant M1. The material of the buffer member 30 is not particularly limited; examples include shock-absorbing soft polyurethane foam. The buffer member 30 mitigates the impact on the occupant M1. Furthermore, since the buffer member 30 is provided on the surface opposite to the body of the occupant M1, it does not interfere with the deployment of the widened portion 10C. The buffer member 30 may also be covered by a fabric cover member together with the widened portion 10C. It should be noted that in the technology disclosed herein, it is sufficient to provide a buffer member on at least the surface opposite to the occupant's body in the widened portion of the seat belt; alternatively, a buffer member may be provided on the portion of the seat belt other than the widened portion.

[0084] <Implementation Method 3>

[0085] The seat belt device according to Embodiment 3 will now be described. Figure 13 This is a perspective view showing the normal state of the widened portion 10D of the seat belt device 1000D according to Embodiment 3. Figure 14 This is a perspective view showing the widened state of the widened portion 10D of the seat belt device 1000D according to Embodiment 3. In the description of Embodiment 3, it is compared with... Figures 1 to 7 The description focuses on the differences of the seat belt device 1000 in Embodiment 1, and omits detailed descriptions of the similarities with the seat belt device 1000.

[0086] like Figure 13 as well as Figure 14 As shown, the widened portion 10D according to Embodiment 3 includes: a first movable portion 7; a second movable portion 8, which is disposed adjacent to the first movable portion 7 in the width direction of the widened portion 10D; and a plurality of connecting members 9, which connect the first movable portion 7 and the second movable portion 8. The first movable portion 7 and the second movable portion 8 are formed of fabric members. The first movable portion 7 includes a first end portion 101 of the widened portion 10D and is connected to the belt portion 20 via a connecting portion C1. The first movable portion 7 extends from the connecting portion C1 along the extension direction of the seat belt 100D. The second movable portion 8 includes a second end portion 102 of the widened portion 10D and is connected to the belt portion 20 via a connecting portion C2. The second movable portion 8 extends from the connecting portion C2 along the extension direction of the seat belt 100D. The front end portion 71 of the first movable portion 7 is connected to the base end portion 82 of the second movable portion 8, and the front end portion 81 of the second movable portion 8 is connected to the base end portion 72 of the first movable portion 7. The connecting members 9 are metal plate members. The connecting member 9 is connected to the first movable part 7 via a first rotating shaft 91 extending in the thickness direction of the widened portion 10D, and to the second movable part 8 via a second rotating shaft 92 extending in the thickness direction of the widened portion 10D. The connecting member 9 is rotatable about the first rotating shaft 91 and the second rotating shaft 92. It should be noted that the widened portion 10D is covered by a fabric cover member (not shown).

[0087] The connecting member 9 rotates such that the first movable part 7 and the second movable part 8 are separated from each other in the width direction of the widened part 10D, thereby causing the widened part 10D to rotate from... Figure 13 The normal state shown becomes as follows Figure 14 The widened portion 10D is shown in the diagram. The widened portion 10D has an offset member (not shown) that offsets the connecting member 9 to maintain the widened portion 10D in its normal state. Figure 13As shown, in the normal state, a folded portion 73 is formed near the front end portion 71 of the first movable portion 7, and a folded portion 83 is formed near the front end portion 81 of the second movable portion 8. Furthermore, in the normal state, in the extending direction of the widened portion 10D (the extending direction of the seatbelt 100D), the first rotation axis portion 91 is located closer to the second end portion 102 of the widened portion 10D than the second rotation axis portion 92 located above the connecting member 9. Therefore, when tension exceeding the biasing force of the biasing member acts on the seatbelt 100D, thereby stretching the first movable portion 7 and the second movable portion 8 in opposite directions, the connecting member 9 rotates about the first rotation axis portion 91 and the second rotation axis portion 92. The biasing member is not particularly limited; for example, a spring can be listed.

[0088] Under normal conditions, when an impact causes the occupant M1's body to rest against the seatbelt 100D, resulting in a tension exceeding a predetermined level acting on the seatbelt 100D, the connecting member 9 rotates around the first rotating axis 91 and the second rotating axis 92. Consequently, the first movable part 7 and the second movable part 8 separate from each other in the width direction of the widened part 10D, and the widened part 10D is widened. As described above, the front end portion 71 of the first movable part 7 is connected to the base end portion 82 of the second movable part 8, and the front end portion 81 of the second movable part 8 is connected to the base end portion 72 of the first movable part 7. Furthermore, as... Figure 14 As shown, the widened portion 10D is in a widened state, thereby causing the first movable portion 7 and the second movable portion 8 to be fully extended. Therefore, in the widened state, the connecting member 9 rotates further to restrict the first movable portion 7 and the second movable portion 8 from approaching each other. In the widened state, when the tension acting on the seat belt 100D is lower than a predetermined value, the connecting member 9 rotates under the biasing force of the biasing member, thereby causing the widened portion 10D to return to its normal state.

[0089] In this embodiment, the widened portion 10D can also be in a widened state, thereby dispersing the load acting on the body of the occupant M1 and mitigating the forward tilting of the occupant M1. As a result, the occupant M1 can be protected from impact. Furthermore, by separating the first movable portion 7 and the second movable portion 8 in the width direction, the widened portion 10D changes from its normal state to a widened state. Therefore, the thickness of the widened portion 10D in the widened state is equal to that in the normal state. Additionally, the cross-sectional areas of the connecting portions C1 and C2 in the widened state of the widened portion 10D are equal to those in the normal state. The widened portion 10D is widened without a decrease in the strength of the connecting portions C1 and C2, thus suppressing damage to the connecting portions C1 and C2.

[0090] Furthermore, in this embodiment, the widening portion 10D changes from its normal state to a widened state by applying tension to the seat belt 100D, thereby causing the occupant M1 to rest against it. That is, since the widening portion 10D is widened using the load caused by the occupant, a separate drive source is not required.

[0091] [Modification of Implementation Method 3]

[0092] The following describes a modified example of the seat belt device according to Embodiment 3. In the description of the modified example, the description will focus on the differences from the seat belt device 1000D, and detailed descriptions of the points that are the same as those in the seat belt device 1000D will be omitted. Figure 15 This is a perspective view showing the normal state of the widened portion 10E of the seat belt device 1000E according to a variation of Embodiment 3. Figure 16 This is a perspective view showing the widened state of the widened portion 10E of the seat belt device 1000E according to a modified example of Embodiment 3.

[0093] like Figure 15 as well as Figure 16 As shown, the widened portion 10E in the modified embodiment 3 includes: a first movable portion 7E; a second movable portion 8E, which is disposed adjacent to the first movable portion 7E in the width direction of the widened portion 10E; and a plurality of connecting members 9 that connect the first movable portion 7E and the second movable portion 8E. The first movable portion 7E and the second movable portion 8E are made of metal. The first movable portion 7E includes a first end portion 101 of the widened portion 10E, which is connected to the belt portion 20 via a connecting portion C1 that serves as an insertion hole for the belt portion 20. The first movable portion 7E extends from the connecting portion C1 along the extending direction of the seat belt 100E. The second movable portion 8E includes a second end portion 102 of the widened portion 10E, which is connected to the belt portion 20 via a connecting portion C2 that serves as an insertion hole for the belt portion 20. The second movable portion 8E extends from the connecting portion C2 along the extending direction of the seat belt 100E. The connecting member 9 is connected to the first movable part 7E via the first rotating shaft 91, and to the second movable part 8E via the second rotating shaft 92. It should be noted that the widened part 10E is covered by a fabric cover member (not shown).

[0094] The connecting member 9 rotates in such a way that the first movable part 7E and the second movable part 8E are separated from each other in the width direction of the widened part 10E, thereby causing the widened part 10E to move from such a position as... Figure 15 The normal state shown becomes as follows Figure 16 The widened state is shown. In the widened portion 10E, there is an offset member (not shown) that offsets the connecting member 9 to maintain the widened portion 10E in its normal state. Figure 15As shown, in the normal state, in the extending direction of the widened portion 10E (the extending direction of the seat belt 100E), the first rotating shaft portion 91 is located closer to the second end portion 102 of the widened portion 10E than the second rotating shaft portion 92 located above the connecting member 9.

[0095] Under normal conditions, when an impact causes a tension exceeding a predetermined value to be applied to the seat belt 100E, the connecting member 9 rotates around the first rotating shaft 91 and the second rotating shaft 92, thereby causing the first movable part 7E and the second movable part 8E to separate from each other in the width direction of the widened part 10E, and the widened part 10E is in a widened state. Wherein, as... Figure 16 As shown, the first movable part 7E and the second movable part 8E are formed with a limiting part R1, which abuts against the connecting member 9 in the widened state, thereby allowing the connecting member 9 to rotate further to limit the first movable part 7E and the second movable part 8E from approaching each other. In the widened state, when the tension acting on the seat belt 100E is lower than a predetermined value, the connecting member 9 rotates under the biasing force of the biasing member, thereby allowing the widened part 10E to return to its normal state.

[0096] <Other>

[0097] The preferred embodiments of this disclosure have been described above, but the various solutions disclosed in this specification can also be combined with any other features disclosed in this specification.

[0098] Explanation of reference numerals in the attached figures

[0099] 1000··Seatbelt device

[0100] 100·· Seatbelt

[0101] 10. Widening section

[0102] 1. Drive Unit

[0103] 11··Dielectric elastomer layer

[0104] 12, 13... Electrode layers

[0105] 2. Side conductive part

[0106] 5. Thin-sheet components

[0107] 6. Condition Maintenance Components

[0108] 7. First movable part

[0109] 8. Second movable part

[0110] 9··Connecting structural components

[0111] 400·· Tongue component

[0112] 403, 404... Tongue-side conductive part

[0113] 500·· Buckle Components

[0114] M1 Crew

Claims

1. A seatbelt device, It includes seat belts that restrain occupants to seats in a vehicle, the seat belts being secured to a fixed object within the vehicle. in, The seat belt includes a widening portion, which is at least a part of the seat belt and is a band-shaped widening portion that abuts against the occupant's body. In the event of an impact to the occupant's body, the widening portion deforms from its normal state in a widened manner. The thickness of the widened portion in its widened state is not greater than the thickness of the widened portion in its normal state before widening, and the cross-sectional area of ​​the connection portion between the widened portion in its widened state and other parts of the seat belt, excluding the widened portion, is at least equal to the cross-sectional area of ​​the connection portion in its normal state. The widened portion returns to its normal state after being widened.

2. The seat belt device according to claim 1, The widened portion includes a driver portion, wherein a dielectric elastomer layer of the driver portion and a pair of electrode layers sandwiching the dielectric elastomer layer are stacked in the thickness direction of the widened portion. In the normal state, a predetermined voltage is applied to the pair of electrode layers, and the dielectric elastomer layer is compressed in the thickness direction of the widened portion, thereby widening the widened portion.

3. The seat belt device according to claim 2, It also has a tongue component that is inserted into the seat belt; And a buckle component, which is fixed to the vehicle and can engage with the tongue component. The seat belt has a belt-side conductive portion connected to each of the pair of electrode layers in the driver section. The tongue member has a tongue-side conductive portion configured to contact the belt-side conductive portion of the seat belt into which the tongue member is inserted. The tongue member is engaged with the buckle member to restrain the occupant via the seat belt, and the power supply circuit for applying the predetermined voltage to the pair of electrode layers and the tongue-side conductive portion are connected via the buckle member.

4. The seat belt device according to claim 1, The widened portion includes: A thin sheet component that can change state between a folded state and an unfolded state in the thickness direction of the widened portion; And a state-maintaining member, which, in the normal state, maintains the state of the sheet member in the folded state. In the normal state, when a tension exceeding a predetermined value is applied to the seat belt, the state-maintaining member is released, causing the sheet member to be in the unfolded state, thereby widening the widened portion.

5. The seat belt device according to claim 4, The sheet member is configured to have a restoring force to return to the unfolded state in the folded state.

6. The seat belt device according to claim 1, The widened portion includes: The first movable part includes one end of the widened part in the extending direction of the seat belt; A second movable part, including the other end of the widened part, and disposed adjacent to the first movable part in the width direction of the widened part; and a connecting member connecting the first movable part and the second movable part. In the normal state, when a tension exceeding a predetermined amount is applied to the seat belt, the connecting structure rotates such that the first movable part and the second movable part rotate apart from each other in the width direction of the widened part, thereby widening the widened part.

7. The seat belt device according to claim 6, The connecting member is connected to the first movable part via a first rotating shaft extending in the thickness direction of the widened portion, and to the second movable part via a second rotating shaft extending in the thickness direction of the widened portion. In the normal state, in the extending direction of the widened portion, the first rotating shaft portion is located closer to the other end side of the widened portion than the second rotating shaft portion.

8. The seatbelt device according to any one of claims 4 to 7, The widened portion changes the tension of the seat belt from the normal state to the widened state by causing the occupant to lean against the seat belt.

9. The seatbelt device according to any one of claims 1 to 7, A cushioning member is provided on the surface of at least the widened portion of the seat belt opposite to the occupant's body.

10. A method for restraining occupants using a seatbelt device. The seatbelt device includes a seatbelt that restrains an occupant to a seat in the vehicle, the seatbelt being secured to a fixed object within the vehicle. in, The method includes: The widened portion is formed as at least a part of the seat belt, the widened portion being a band-shaped widened portion that abuts against the occupant's body and deforms from its normal state to widen in the event of an impact to the occupant's body; Due to the impact, by bringing the occupant's body against the seat belt, the tension acting on the seat belt, including the widened portion, causes the widened portion to be in a widened state. The thickness of the widened portion in the widened state is not greater than the thickness of the widened portion in the normal state before the widening, and the cross-sectional area of ​​the connection portion between the widened portion in the widened state and the portion of the seat belt other than the widened portion is at least equal to the cross-sectional area of ​​the connection portion in the normal state. The contact area between the widened portion in the widened state and the occupant's body is larger than the contact area in the normal state, thereby dispersing the load acting on the occupant's body; The widened portion returns to its normal state after being widened.

Images