Vehicle seats with shock absorption mechanisms

Abstract

When a four-point seat belt is integrated into the seat structure, the shoulder belt load is concentrated on the upper part of the seat back frame during a frontal collision. This provides an occupant restraint seat that ensures good occupant restraint without causing a significant increase in frame reinforcement or weight due to an increase in the forward tilting moment. [Solution] A neck anchor 5 is provided on the upper part of the seat back 41 to guide the shoulder belt 31R, and the neck anchor is attached to a subframe 11 supported by the seat back frame 10 via a connecting part and an extension load element. In the event of a collision, the connecting part is detached with a predetermined load, the extension load element is extended and a load is generated, and the neck anchor and subframe are moved in the direction of the occupant's movement, thereby absorbing the occupant's kinetic energy and reducing the peak load of the forward tilt moment generated in the seat back frame.

Description

Technical Field

[0001] This invention relates to a seat (hereinafter referred to as a "seat") mounted on a moving body on which a human body can ride, and a seat belt mechanism attached to the seat.

Background Art

[0002] In a moving body (hereinafter referred to as a "vehicle") on which a human body can ride, in order to protect an occupant from an impact caused by a collision or the like, as a seat belt attached to a seat mounted on the vehicle, a so-called four-point seat belt device in which two belts are drawn out from the upper part of the backrest (hereinafter referred to as a "seat back") is known (see, for example, Patent Document 1 and Patent Document 2). In this seat-integrated four-point seat belt device, a large forward tilting moment occurs in the seat back during a frontal collision, and as a result, it is considered necessary to provide special reinforcement to the seat frame (see, for example, Patent Document 3 and Patent Document 4. These are examples of three-point seat belt devices, but the same reinforcement is considered necessary in a four-point seat belt device).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Patent Document 6

Non-Patent Documents

[0004] [Non-Patent Document 1] Chantal Parenteau; et al., Performance Evaluation of Seat-Integrated Restraint Systems (SIRS) in Controlled Crashes, IRCOBI conference 2024, https: / / www.ircobi.org / wordpress / downloads / irc24 / pdf-files / 24124.pdf (Accessed December 8, 2025) [Overview of the project] [Problems that the invention aims to solve]

[0005] In seats equipped with the four-point seat belt system described in Patent Documents 1 and 2, during frontal collisions, which occur frequently, a large portion of the impact load that restrains the occupant's upper body is applied to the upper part of the seat back frame. As a result, an excessive forward tilting moment is generated in the seat back, with the recliner, located at the key point between the seat and the seat cushion, as the center of rotation. This phenomenon is not excessive when a seat belt is not attached to the seat.

[0006] In the vehicle seats described in Patent Documents 3 and 4, the shoulder belts of the three-point seat belts are extended from the seat back located behind the left or right shoulder of the seated occupant. To provide resistance to the aforementioned forward tilting moment, the load capacity of the recliner has been increased and reinforcing members have been added to the seat back frame. Furthermore, Patent Document 4 describes an asymmetrical structure in which only the side on which the input load of the shoulder belt acts is extremely reinforced. Seats that have an impact load applied to the upper part of the seatback that restrains the occupant's upper body face the following challenges: (a) In order to suppress the generation of a forward tilt moment in the seatback, the recliner needs to be made larger, heavier, and more expensive due to its increased load capacity. (b) Since the seat frame is also subjected to a forward tilt moment, this may lead to increased costs due to increased thickness of the sheet metal parts that make up the seat frame, or the adoption of aluminum die-cast or aluminum extruded products that can be expected to have higher strength and rigidity. In addition, a configuration in which only one side of the seatback is significantly reinforced may impair occupant protection in a rear-end collision (see, for example, Non-Patent Document 1).

[0007] The objective of this invention is to provide a seat frame that can withstand a large forward tilting moment in a seat incorporating a four-point seat belt, without making significant changes to the conventional seat frame. [Means for solving the problem]

[0008] The vehicle seat according to claim 1 comprises a seat cushion that supports the buttocks of a seated occupant P from below the seat, a seat back that supports the back of the seated occupant from behind the seat, and a lap belt that is stretched in the width direction of the seat along the waist of the seated occupant P seated on the seat cushion. The seat back has at least one opening at the top (hereinafter referred to as the upper hole), and at least two shoulder belts are extended from the upper hole. The upper hole is provided with a neck anchor having a belt routing function, which bears the load generated when the shoulder belts are extended during normal use and in the event of a collision. The two shoulder belts in this embodiment are elongated members having a predetermined width dimension.

[0009] The seat back has a frame (hereinafter referred to as the seat back frame), and the neck anchor is equipped with a mechanism that, when an impact force is generated due to a vehicle collision or the like, moves away from the seat back frame and moves in the direction of movement of the occupant seated in the seat.

[0010] The seat back frame and the neck anchor are normally fixed to each other during use, but when a load exceeding a predetermined amount is applied from the shoulder belt due to the movement of the seated occupant, the neck anchor can detach from the seat back frame in the direction of that movement.

[0011] In the vehicle seat according to claim 2, the seat back frame and the neck anchor are connected via a connecting component S and an extension load element R, and are fixed to each other during normal use. When a load exceeding a certain amount is applied from the shoulder belt in a predetermined direction due to the movement of the seated occupant, the connecting component S detaches from the seat back frame at a predetermined point, and subsequently, the extension load element R extends under tensile load, generating a predetermined load, while the neck anchor moves relative to the seat back frame.

[0012] The connecting component S and the extension load element R may be made of metal, a resin molded body, a fabric material, or a composite material or assembly thereof.

[0013] According to the vehicle seat described in claim 2, the initial detachment load of the connecting component S and the load generated when the extension load element R is extended work together to absorb kinetic energy while mitigating the peak load of the forward tilt moment generated in the seat back frame, thereby ensuring that the seated occupant is securely restrained via the shoulder belt.

[0014] The vehicle seat according to claim 3 has a pair of rod-shaped support parts connected to the lower part of the neck anchor that bears the load of the left and right shoulder belts, and the lower ends of the support parts are fixed to the lower part of the seat back frame. This makes it possible to support the downward load generated on the neck anchor at the lower part of the seat back frame, which has relatively high strength, via the support parts.

[0015] According to the vehicle seat described in claim 3, without excessively increasing the strength of the upper and middle parts of the seat back, the movement trajectory of the neck anchor can be controlled substantially parallel to the seat cushion. As a result, while further stabilizing the movement of the neck anchor, the load acting on the seat back frame can be reduced.

Advantages of the Invention

[0016] The vehicle seat and seat belt device according to the present invention have an advantageous effect of being excellent in achieving both restraint performance and mass production mountability while following the conventional seat frame structure.

Brief Description of the Drawings

[0017] [Figure 1] It is a perspective view of the vehicle seat according to the present invention from the front left and obliquely upward. [Figure 2] It is a right side view of the first embodiment related to the sub-frame of the seat back in FIG. 1. [Figure 3] It is a front view of FIG. 2. [Figure 4] It is a right side view of the second embodiment related to the sub-frame of the seat back in FIG. 1. [Figure 5] It is a front view of FIG. 4. [Figure 6] It is a right side view of a seat equipped with the seat backs of FIGS. 4 and 5 with an occupant seated. [Figure 7] It is a view when the mechanism operates due to an impact from the front direction of the occupant in FIG. 6. [Figure 8] It is a cross-sectional view taken along the line a-a of FIG. 6. [Figure 9] It is a cross-sectional view taken along the line b-b of FIG. 7. [Figure 10] It is a conceptual diagram of an operation example when the impact direction changes in FIG. 9. <00001​​​​​​​This is a front view of the third embodiment relating to the seat back subframe shown in Figure 1. [Figure 14] This is a conceptual diagram that uses the tear load of a fabric as an example of a load generation element R. [Figure 15] Figure 14 is a conceptual diagram of the tear load line. [Figure 16] Figure 4 shows an example of a change in the retractor arrangement in the second embodiment. [Figure 17] This is a left side view of Figure 16. [Modes for carrying out the invention]

[0018] A vehicle seat according to an embodiment of the present invention will be described with reference to Figures 1 to 17. The arrows FR, UP, LH, and RH in the figures indicate the front, top, left, and right sides of the seat, respectively, as seen from the perspective of a passenger seated in the vehicle seat. Hereafter, when simply using the directions front-to-back, up-and-down, and left-to-right, unless otherwise specified, these refer to the front-to-back direction of the seat, the up-and-down direction of the seat, and the left-to-right direction of the seat.

[0019] Figure 1 shows a vehicle seat 2 equipped with a seat belt device according to the present invention, and an occupant P seated in the seat 2 is shown by a dashed line. Figure 1 is a perspective view taken from the upper left as seen from the perspective of the seated occupant P. The vehicle seat 2 includes a seat cushion 40 that supports the seated occupant P from below, and a seat back 41 that is supported at the rear end of the seat cushion 40 and supports the seated occupant P from the rear. A headrest portion is formed at the upper end of the seat back 41 to support the head of the seated occupant P from the rear. The back of the seated occupant P is supported by the seat back 41, and the buttocks are supported by the seat cushion 40, and the upper body and waist are further restrained by the seat belt device worn by the seated occupant P.

[0020] The seat belt device of this embodiment comprises a pair of left and right shoulder belts 31L and 31R that restrain the left and right shoulders of the seated occupant P, and a lap belt that is stretched in the seat width direction along the iliac crest of the pelvis located at the waist of the seated occupant P, forming a roughly triangular delta shape in a front view. Each left and right shoulder belt 31 is extended from at least one opening 7 that is opened in the upper part of the seat back 41 located behind the neck of the seated occupant P, and each extends downward after passing over the left and right clavicles of the seated occupant P, and toward the side of the seated occupant P. The right shoulder belt 31R is folded back through an insertion hole formed in the tongue plate 34 and connects with the lap belt, and this configuration is the same as that of a general three-point seat belt device. On the other hand, the left shoulder belt 31L is connected to the lap belt on the left side of the waist of the seated occupant P. Note that the configuration of the lower part of these shoulder belts may be reversed left and right. In other words, the buckle 30 and tongue plate 34 may be provided on the left side of the seat and connected to the lap belt on the right side of the seat.

[0021] Furthermore, the coupling structure and interlocking structure on the lower side of the shoulder belt 31 are not limited to Figure 1 and the above description, and may be configured such that the lower end of the shoulder belt 31 is terminated in the middle lower part of the seat back 41, as shown in Patent Document 5, which is disclosed as prior art. A buckle 30 is fixed to the seat cushion 40 as a locking part, and a tongue plate 34 is locked to the buckle 30. In addition, a retractor for winding up the left shoulder belt 31L and the right shoulder belt 31R is locked inside the seat back 41, and the shoulder belts 31 that are extended upward from the retractor are guided forward from the opening 7 via the neck anchor part 5.

[0022] Although not shown in detail in Figure 1, a subframe 11 equipped with a neck anchor portion 5 that receives the extension load of the shoulder belt 31 is disposed inside the seat back 41. The subframe 11 is supported in a predetermined manner by the seat back frame, which is the skeleton of the seat back 41, and by receiving the load input from the shoulder belt 31 during a vehicle collision, etc., it aims to improve the restraint performance of the seated occupant P and to optimize the load burden on the seat back frame.

[0023] Figure 2 is a right side view of the subframe 11 of the seat back 41 of the <First Embodiment> shown in Figure 1, and Figure 3 is a front view thereof. Inside the seat back 41, in addition to the seat back frame 10 which is the framework that forms the entire seat back, there is a subframe 11 which is equipped with a retractor and a seat belt.

[0024] The subframe 11 is provided with a neck anchor portion 5, which is roughly U-shaped when viewed from the front, in order to change the direction of the belt unwound from the retractor 35 toward the occupant. The shoulder belt 31, which is unwound generally upward from the retractor 35, is stretched over the neck anchor portion 5, passes through the opening 7 at the top of the seat back, and is unwound toward the front of the seated occupant P. The belt routing portion of the neck anchor portion 5 has a belt path setting function and is roughly straight in the left-right direction. As shown in Figures 2 and 3, the subframe 11 is supported by the seat back frame 10 via a connecting part S51, an extension load element R50, and a tension element 13. When the shoulder belt 31 is strongly pulled forward due to an impact such as a collision, the connecting part S51 detaches from the seat back frame 10 at a predetermined point, and the subframe 11 moves forward tilting together with the neck anchor portion 5 and the retractor 35. This state is shown by a dotted line in Figure 2.

[0025] When a load is applied from the shoulder belt 31 to the neck anchor portion 5 during a frontal collision, the extension load element R50 extends between the upper part of the seat back frame 10 and the neck anchor portion 5, generating a constant set load, and absorbs the kinetic energy of the occupant P. As a result, the sudden load application to both the occupant P and the seat back frame 10 is mitigated, and the seat back frame 10, as a support portion, can stably receive the restraining load of the occupant P while allowing elastic deformation.

[0026] The tension element 13 connects the middle section of the seat back frame 10 to the lower section of the subframe 11, and plays a role in stabilizing the behavior of the subframe 11 when an impact is applied and the subframe 11 tilts forward. Furthermore, from the viewpoint of adjusting the seating comfort of the occupant P, its material may be a spring material with cushioning properties, or it may be a wire with low elasticity.

[0027] The neck anchor section 5 is formed in a roughly U-shape. As shown in Figure 3, this is because, in addition to the straight belt routing section, vertical walls are formed at both the left and right ends by connecting parts S, resulting in a roughly U-shaped configuration. These vertical walls function as stoppers when the shoulder belt slides laterally, preventing the belt from slipping off the straight belt routing section.

[0028] Figure 4 is a right side view of the <Second Embodiment> relating to the seat back subframe of Figure 1, and Figure 5 is a front view thereof. The subframe 11, which includes the neck anchor portion 5, further has a lower support portion 12, the lower end of which is connected to the lower part of the seat back frame 10. A bracket is formed in the middle of the lower support portion 12, and a retractor 35 is fixed to it. Because the subframe 11 with the neck anchor portion 5 is fixed to the lower part of the seat back frame 10, when the shoulder belt 31 is pulled far forward of the seated occupant P due to an input such as an impact, the neck anchor portion 5 moves forward as in the first embodiment, and at this time, because the lower support portion 12 is provided, the neck anchor portion 5 moves so as to rotate around the fixing portion with the lower part of the seat back frame 10 as a pivot point. Furthermore, since the movement of the subframe 11 in the left-right direction is restricted by the lower support portion 12, the movement of the neck anchor portion 5 is limited to approximately the front-rear direction of the seated occupant P, and its movement path can be made even more stable.

[0029] Furthermore, since the subframe 11 is connected to the lower part of the seat back frame 10 while maintaining downward rigidity, the downward load is borne by the lower part of the seat back frame 10, and the stabilization of the above-mentioned movement path improves the degree of freedom in the seat layout regarding the lower anchoring position of the retractor 35 and shoulder belt. For example, it can be installed on the seat cushion as shown in Figures 16 and 17, which will be described later. The lower support portion 12 of the subframe 11 is constructed from steel pipe material, glass fiber reinforced resin, or a composite material or assembly thereof, and is preferably strong from the viewpoint of preventing deformation when an occupant is restrained. In the illustrated form, the lower support portion 12 of the subframe 11 is a straight shape advantageous for load support, but it may also be a curved shape that follows the shape of the seat back frame 10, or a shape that takes into account the support of the air conditioning fan built into the seat back and the lumbar support mechanism.

[0030] A support section for a seat belt retractor 35 is formed inside the subframe 11, which has two lower support sections 12 on the left and right sides, and the retractor 35 is firmly fastened with screws or the like. Furthermore, it is preferable that the lower part of the subframe 11 and the lower part of the seat back frame 10 are joined by screws. Compared to welded joints, this is expected to improve ease of assembly and maintenance, as well as improve the robustness of the movement path of the subframe 11 during a collision. Furthermore, the force involved in the screw fastening of the seat back frame and subframe. Due to deformation or failure of components along the load path, the planned process It is also conceivable that it could extend outwards to contribute to absorbing the kinetic energy of the occupants.

[0031] Figure 6 is a right side view showing an occupant P seated in a vehicle seat equipped with the seat back shown in Figures 4 and 5. The seat back has a subframe 11 with a neck anchor portion 5. A shoulder belt 31 extends from the top of the seat back and is wrapped downwards from the occupant P's shoulders towards their sides, and a lap belt is wrapped around their waist. The upper part of the subframe 11 is connected to the seat back frame 10 via a connecting component S51 and an extension load element R50 near the neck anchor portion 5, and the lower part of the subframe 11 is fixed to the lower part of the seat back frame 10. The entire subframe 11 is enclosed inside the seat back surface 6, and its presence is not visible from the outside or surface of the seat.

[0032] This figure shows an example of a front seat for a vehicle, but the technology of this invention can be applied to seats in various types of mobile vehicles, such as rear seats and bus seats. Note that cross-sectional views are interspersed in this figure as needed to facilitate understanding of the internal structure.

[0033] Figure 7 shows the state in which an occupant P, seated in the seat shown in Figure 6, moves in the direction of impact due to a frontal impact and is restrained by the shoulder belt 31. A restraining force from the occupant P acts on the shoulder belt 31, and this restraining force causes the shoulder belt 31 to pull the neck anchor portion 5 forward, causing the neck anchor portion 5 to detach from the seat back frame 10 together with the connecting component S51. In Figure 7, the dotted line indicates the state of the occupant, etc., before the collision, and the F arrow indicates the direction of the force acting on the occupant.

[0034] The seat back frame 10 and the subframe 11 having the neck anchor portion 5 share and bear the restraining force of the occupant P transmitted from the shoulder belt 31 when the extension load element R50 extends under a predetermined load, thereby mitigating the impact and absorbing the kinetic energy of the occupant P.

[0035] When a load is applied from the shoulder belt 31 to the neck anchor portion 5 during a frontal collision, the connecting component S51 detaches from the seat back frame 10, and the extension load element R50 extends between the upper part of the seat back frame 10 and the neck anchor portion 5, generating a constant set load. This mitigates the sudden load application to both the occupant P and the seat back frame 10, and the seat back frame 10, as a support portion, undergoes plastic and elastic deformation, thereby enabling it to withstand the restraining load of the occupant P.

[0036] The seat cover 6 generally encompasses these movements, and is pulled starting from the movement of the neck anchor portion 5, compressing the pad member 3 and ultimately transmitting that force to the seat back. However, it may tear starting from a seam or other point along the way. This reduces the excessive forward tilting moment acting on the seat back frame 10, and the load at the time of tearing can be used as one element in absorbing the kinetic energy of the occupant P. The seat cover 6 also serves to prevent the internal mechanism from being exposed to the occupant.

[0037] The opening cover 9 is loosely fixed to the seat surface 6 and the neck anchor portion 5 to such an extent that it can move flexibly in accordance with the movement of the seat surface 6 and the neck anchor portion 5.

[0038] Figure 8 is a cross-sectional view of section aa in Figure 6. The left and right shoulder belts 31L and 31R are stretched across the neck anchor portion 5 and extend in the FR direction in the figure. The subframe 11, which includes the neck anchor portion 5, is fixed to the seat back frame 10 via a connecting component S51 and an extension load element R50. The connecting component S51 extends its mounting portion toward the rear of the occupant and engages with the seat back frame 10 by conforming to its shape. The extension load element R50 has both ends fixed to the seat back frame 10 and the neck anchor portion 5, respectively. The seat cover 6 encloses these structures and covers the surface of the seat back, and a pad member 3 is interposed inside the seat cover 6.

[0039] Figure 9 is a cross-sectional view of bb in Figure 7. The neck anchor portion 5 is pulled by the shoulder belt 31, releasing the engagement between the connecting component S51 and the seat back frame 10, and moving forward. Both ends of the extension load element R50 remain fixed to the seat back frame 10 and the neck anchor portion 5, and extend while connecting them, generating a set load during the extension process, thereby absorbing the kinetic energy of the occupant P.

[0040] Furthermore, the configuration by which the connecting component S detaches from the seat back frame is not limited to the separation method by deformation of the fitting portion to the seat back frame as shown in the figure. Any means by which the component can detach due to impact, such as creating a stress concentration point to cause fracture, using electrical means for ignition, or unlocking with an actuator, is acceptable. The illustrated configuration is merely an example.

[0041] Figure 10 is a conceptual diagram of an example of operation when the input direction in Figure 9 is changed. The shoulder belt is being pulled in a direction slightly inclined from the front. Compared to the initial state before being pulled, as shown in Figure 8, the neck anchor part 5 moves in an oblique direction. Similar to Figure 9, the connecting part S51 detaches from the seat back frame, and the load generating element R50 extends and generates a load.

[0042] Figure 11 is a conceptual diagram of operation in which an extension load element R is added to Figure 10. This is a conceptual diagram of operation when an extension load element R is added by crossing from the right side of the seat back frame to the left side of the neck anchor part 5, and from the left side of the seat back frame to the right side of the neck anchor part 5. With this configuration, the difference in input load to the left and right extension load elements R that occurs when the shoulder belt 31 is pulled in an oblique direction is reduced, and it is expected that this will serve as an adjustment means for more stable operation.

[0043] Figure 12 shows an example in which a subframe 11 with a lower support portion is applied to a seat back frame 10 based on the second embodiment of Figure 4, which is a separate headrest type seat back 41. In this way, the same subframe 11 can be applied to the separate headrest type as well. Although connecting parts S51 and the like may be arranged to match the shape of the seat back frame, the fixing of the lower support portion to the lower part of the seat back frame and the movement of the subframe and neck anchor portion 5 when subjected to impact can be kept almost the same.

[0044] Figure 13 is a front view of the <Third Embodiment> relating to the seat back subframe of Figure 1. According to this, a generally downward force is generated in the neck anchor portion 5 due to impact, etc. Since the load is borne at the top of the seat back frame, the subframe can be made small and lightweight as a structure that supports the occupant P in the seat back, thereby mitigating the impact transmitted to the seat back frame. Detailed structural information, such as connecting parts, is not shown here. In addition, the arrangement of belts and retractors can be fixed to the seat cushion as shown in Figures 16 and 17, which will be described later, in addition to the method of fixing them from the seat back frame via bracket members. However, in order for the impact force to be absorbed at the top of the seat back frame, it would be necessary to significantly increase the resistance to the forward tilting moment, which would require a substantial reinforcement of the seat back frame, potentially resulting in disadvantages in terms of cost and weight.

[0045] Figure 14 is a conceptual diagram of a configuration that generates a tear load by pulling a fabric with cuts in it, as an example of a load generating element 50. By making cuts from the short side of a strip-shaped fabric and pulling the separated ends together, the weft threads are sequentially cut starting from the cuts, and the fabric is torn in a substantially straight line, utilizing this property. The load generated per stroke at this time is used as the load generating element. From the viewpoint of obtaining stable load characteristics, it is desirable to use a woven fabric composed of warp threads and weft threads.

[0046] The load generating element 50 can be constructed at low cost by utilizing the tear load of a relatively inexpensive fabric as an industrial product. Other load generating means that can be employed include tensile or tear loads of metal materials, plastic deformation of metal materials, deformation of molded resin bodies, and mechanisms that utilize tensile loads or friction between components.

[0047] Figure 15 is a conceptual diagram of the tear load characteristics of the fabric shown in Figure 14. The vertical axis represents the tear load, and the horizontal axis represents the distance the fabric is torn as the stroke. Generally, the tear load of a fabric has the characteristic of providing a roughly constant load as the stroke increases, thus providing a load characteristic suitable for absorbing impact energy.

[0048] The vertical axis on the right shows the number of fabric pieces to be torn. By sewing together the required number of fabric pieces according to the desired load characteristics in advance, it is possible to output the desired tear load characteristics and control the load.

[0049] Figure 16 shows an example of a modified retractor arrangement in the second embodiment of Figure 4. Figure 17 is a left side view of Figure 16. The structure of the seat back and subframe is the same as in the second embodiment, but the retractor is positioned under the seat cushion instead of inside the seat back, and the belt routing is changed. The belt is taken out almost horizontally from the retractor, then changes direction almost upward via a part of the seat frame, is stretched over the neck anchor portion 5, and is then fed out towards the occupant from the seat back opening. This reduces the number of retractors to one, lowering component costs. In cases where the belt retractor cannot fit inside the seat back due to constraints such as seat back thickness or table installation, the belt retractor can be installed under the seat cushion. In Figures 16 and 17, the belt retractor is installed in the left-right center of the seat cushion, but it may be installed in any of the front, back, left, or right sides below the seat cushion.

[0050] This invention represents an important technological advancement toward the practical application of a four-point seat belt that can solve the problems of conventional three-point seat belts, achieving both high applicability to seat structures and improved restraint performance. In particular, in the ABTS (All-Belts-To-Seat) system, in which all seat belt components are concentrated on the seat side, the invention is characterized by reducing the peak load acting on the seat frame by a subframe structure inside the seat back, and provides a configuration that can realize the seat belt arrangement and retractor fixing structure inside the seat back, as well as suppress the left-right structural difference of the seat back frame 10. As an example of the method of attachment after the occupant is seated, the method described in paragraphs 0030 and 0031 of Patent Document 6 can be cited.

[0051] In this invention, the left and right shoulder belts 31L and 31R of the four-point seat belt system are arranged so that the distance between them increases as they move downwards on the front of the seated occupant P's upper body. As a result, the left and right shoulder belts are less likely to come into contact with the center of the chest, reducing pressure and discomfort, and improving comfort, especially for women with breasts. Furthermore, because the belts follow a path that encloses both sides of the seated occupant P's neck, they also provide excellent restraint of the upper body and neck during collisions from oblique directions, the side, and rollovers, and are expected to provide improved occupant restraint compared to conventional three-point seat belt systems.

[0052] Furthermore, the subframe 11 is supported by the seat back frame 10 via connecting parts S and extension load elements R, mitigating the peak of the restraint load input from the shoulder belt and reducing the load acting on both the human body and the seat back frame 10. The subframe 11, including the neck anchor portion 5, has sufficient support rigidity against lateral and upward movement of the occupant P's upper body, and can effectively suppress these movements. By making the seat itself function as part of the restraint device, load sharing with the vehicle body becomes possible, and by applying appropriate reinforcement designs to both the vehicle body and the seat, it is possible to contribute to vehicle weight reduction, improved fuel efficiency, and even ensuring safety in ultra-compact vehicles.

[0053] The present invention has been described above based on embodiments and modifications. However, the embodiments of the invention described above are intended to facilitate understanding of the present invention and do not limit it. This invention can be modified and improved without departing from its spirit or the scope of the utility model claims, and equivalents thereof are included in this invention. For example, the technical features in the embodiments and modifications corresponding to the technical features in each form described in the utility model summary section can be replaced or combined as appropriate in order to solve some or all of the above-mentioned problems or to achieve some or all of the above-mentioned effects. Furthermore, if a technical feature is not described as essential in this specification, it can be deleted as appropriate. [Explanation of symbols]

[0054] P Crew 2. Vehicle seats 3 Pad component 5. Neck anchor section 6 Seat upholstery 7 Opening 9. Opening cover 10 Seat back frame 11 Subframe 12 Subframe lower support section 13 Tension Elements 15 Retractor support section 16. Lower part of the seat back frame 17 Headrest Frame 18 Tension Elements 20. Overhead subframe 30 buckles 31 Shoulder strap 31L Shoulder Strap L 31R Shoulder Belt R 32 Wrap belt 34 Tang Plate 35 Retractor 40 Seat Cushions 41 Seatback 42 Recliners 50 Extension load element R 51 Connecting part S

Claims

1. In a mobile vehicle capable of carrying a human body, A seat having a seating area and a seat back, From at least one opening formed in the upper part of the seat back, A pair of shoulder straps that are draped downwards, A neck anchor provided near the aforementioned opening, The load on the shoulder belt as it is extended from inside the seat back through the opening is received by the neck anchor. It is equipped with a lap belt that is stretched across the left and right pelvic iliac crests of the seated occupant, The aforementioned seatback has a frame that forms its structure, The neck anchor is connected to the frame, The aforementioned neck anchor, when a load exceeding a predetermined level is generated due to impact, The fixed state with the frame is released, The invention is characterized by having a mechanism that mitigates input to the frame by allowing relative movement to the frame. Crew restraint sheet.

2. The neck anchor and the frame are, They are connected via connecting parts and extension load elements, When the neck anchor separates from the frame, The extension load element is characterized by generating a predetermined load by stretching with plastic deformation, fracture, or friction. The crew restraint seat according to claim 1.

3. The aforementioned neck anchor is It has a support part that extends downward, The support portion is characterized in that it is connected to the frame below it. The occupant restraint seat according to claim 1 or 2.

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