seat belt device

Abstract

To effectively bind a waist part of an occupant to a vehicle seat.SOLUTION: A seat belt device 1 includes: a seat belt 4; a retractor 3 for drawably winding the seat belt 4; a tongue 6 supported on the seat belt 4; a buckle 7 for attaching / detaching the tongue 6; a connection member 12 for connecting the buckle 7 and a seat frame 11 of a vehicle seat 2 or a vehicle body; a tether 10 for connecting the connection member 12 and the tip in the drawing direction of the seat belt 4 below the vehicle seat 2; and a pretensioner 8 for operating at emergency, and drawing the tether 10. A pelvis of an occupant is also supported from an ischium side and held in a ring shape, and a waist part of the occupant is effectively bound while suppressing the load on a human body. According to the seat belt device 1, prevention of a submarine phenomenon, and binding of the occupant in a reclining attitude can be expected.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a seat belt device. [Background technology]

[0002] Conventionally, in a seat belt device attached to a vehicle seat of an automobile or the like, an occupant is restrained by the seat belt in an emergency (hereinafter simply referred to as an emergency) when the vehicle is decelerated at a rate greater than normal, such as during a collision. A three-point seat belt device is generally widely known as a seat belt device. For example, in a three-point seat belt device, the seat belt pulled out from a retractor is guided by a belt guide anchor, and the leading end of the seat belt is fixed to the vehicle body or the seat. A tongue is slidably supported on the seat belt guided by the belt guide anchor. The tongue engages with a buckle fixed to the vehicle body or the seat, allowing the seat belt to be fastened to the occupant.

[0003] When the seat belt is fastened to the occupant, the portion of the seat belt between the belt guide anchor and the tongue functions as a shoulder belt worn around the occupant's shoulders and chest. The portion of the seat belt between the tip fixed to the vehicle body and the tongue functions as a lap belt worn around the occupant's lap (waist). In an emergency, the retractor's locking mechanism is activated to prevent the seat belt from being pulled out, so that the shoulder belt restrains the occupant's shoulders and chest, and the lap belt restrains the occupant's waist.

[0004] A seatbelt device with a pretensioner attached to a retractor is known. In the early stages of an emergency, the pretensioner is activated to quickly reduce seatbelt slack and improve the occupant's restraint effect. In such a seatbelt device, to improve the restraining force of the lap belt around the occupant's waist, it is necessary to increase the tensioning force of the pretensioner. However, there are cases where the restraining force of the shoulder belt exceeds the restraining force of the lap belt.

[0005] When the tension of the pretensioner provided on the retractor is increased to achieve the desired restraining force of the lap belt, there is a risk that the restraining force of the shoulder belt will increase beyond the desired range. With conventional seat belt systems, it has been difficult to efficiently improve the restraining force of the occupant by fastening the lap belt to the vehicle seat while maintaining the same level of restraining force of the shoulder belt.

[0006] To further securely restrain the pelvis, in an emergency, one or both of the seatbelt tips or buckles on the left and right sides of the seated occupant are pulled diagonally downward and rearward from the seated occupant, increasing the pretension load of the lap belt. However, the load is applied to the iliac side of the pelvis by the lap belt. However, the seat cushion does not provide a "reaction force" to withstand the load applied in an emergency, which is related to comfort during normal use. Therefore, there is a risk that the applied load will slip downward toward the occupant's lower back (seat cushion). In terms of human body resistance, due to the expected decline in average bone density associated with the aging population, it is desirable to avoid further strengthening of the pretensioner tension force. Therefore, it has been difficult to further strengthen the pelvic restraint force with conventional vehicle seats and seatbelt systems. Furthermore, installing pretensioners at both anchor points is costly, and incorporating the related components into the vehicle seat is difficult due to layout constraints. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-149949 Summary of the Invention [Problem to be solved by the invention]

[0008] An object of the present invention is to provide a seat belt device that can effectively fasten and restrain the lumbar region of an occupant to a vehicle seat. [Means for solving the problem]

[0009] The seat belt device of the present invention comprises a seat belt, a retractor that winds up the seat belt so that it can be withdrawn, a tongue supported by the seat belt, a buckle to which the tongue is attached and detached, a connecting member that connects the buckle to the seat frame of the vehicle seat or the vehicle body, a tether that connects the connecting member to the tip of the seat belt in the withdrawal direction below the vehicle seat, and a retraction portion that operates in an emergency to retract the tether.

[0010] In one aspect of the present invention, the direction of retraction of the tether has at least a forward element, By retracting the tether, the connecting member and the tip end of the seat belt are retracted with elements toward the center in the left-right direction of the seated occupant.

[0011] In one aspect of the present invention, the tether has one end connected to the connecting member and the other end connected to the tip end of the seat belt, and extends in the left-right direction of the seated occupant.

[0012] In one aspect of the present invention, the tether includes a first tether having one end connected to the connecting member and the other end connected to the tip portion of the seat belt and extending in the left-right direction of the seated occupant, and a second tether having one end connected to the first tether and the other end connected to the retraction portion and extending in the front-rear direction of the seated occupant. It has.

[0013] In one aspect of the present invention, the vehicle seat further includes a first seat frame and a second seat frame provided on both sides of the seated occupant in the left-right direction and extending in the front-to-rear direction of the seated occupant, wherein the tip of the seat belt is connected to the first seat frame by an anchor, the buckle is connected to the second seat frame by the connecting member, and one end of the tether is fixed to the first seat frame and is pulled from the first seat frame to the connecting member and the tip of the seat belt in that order, and the other end is connected to the retraction portion on the second seat frame side.

[0014] In one aspect of the present invention, the portion of the tether from the one end to the connecting member intersects with the portion from the tip of the seat belt to the other end connected to the retraction portion. [Effects of the Invention]

[0015] According to the present invention, the occupant's pelvis is supported by a ring-shaped support from the ischial bone side, effectively restraining the occupant's lower back while reducing the load on the human body. The additional cost is less than or equal to that of current systems, and it is easy to incorporate into vehicle seats. This seatbelt device is expected to prevent the submarine phenomenon and restrain occupants in a reclining position. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a diagram illustrating a configuration of a seat belt device according to an embodiment. [Figure 2] FIG. 2 is a schematic diagram of the seat belt device as viewed from the front of the occupant. [Figure 3] FIG. 2 is a schematic diagram of the lower part of a vehicle seat. [Figure 4] FIG. 2 is a schematic diagram of the lower part of a vehicle seat. [Figure 5] FIG. 10 is a diagram illustrating the configuration of a seat belt device according to another embodiment. [Figure 6] FIG. 10 is a diagram illustrating the configuration of a seat belt device according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, an embodiment will be described with reference to the drawings. In the present invention, the front-rear, up-down, and left-right directions correspond to the front-rear, up-down, and left-right directions of a seated occupant unless otherwise specified.

[0018] Fig. 1 is a configuration diagram of a seat belt device 1 according to an embodiment. Fig. 2 is a schematic diagram of the seat belt device 1 as seen from the front of an occupant when the occupant is fastening a seat belt. Fig. 3 is a schematic diagram of the lower part of a vehicle seat 2.

[0019] This seat belt device 1 is provided in a vehicle seat 2 of an automobile or the like. The vehicle seat 2 has a seat cushion 2b on which an occupant M sits and a seat back 2a rising from the rear of the seat cushion 2b. The vehicle seat 2 is a seat that can accommodate one occupant, such as a driver's seat, a passenger seat, or a captain's seat in the rear. Seat frames 11 extend in the front-rear direction on both the left and right sides of the vehicle seat 2. The vehicle seat 2 may also be a bench seat that can accommodate multiple occupants, with seat belt devices installed for each occupant.

[0020] A typical seat belt device 1 is a three-point seat belt device, which includes a seat belt retractor 3 (hereinafter referred to as "retractor 3") arranged on or near a vehicle seat 2, a seat belt 4 made of webbing that is retractably wound around the retractor 3 and restrains the occupant M in an emergency, a guide anchor 5a (shoulder anchor) that guides the seat belt 4 retracted from the retractor 3 toward the shoulder of the occupant M, a tongue 6 that is slidably supported on the seat belt 4 guided from the guide anchor 5a, and a buckle 7 into which the tongue 6 is releasably inserted and engaged.

[0021] The buckle 7 is connected to one of the seat frames 11 by a connecting member 12 such as a webbing. For example, one end of the connecting member 12 is connected to the buckle 7, and the other end is fixed to the seat frame 11 by a fixing member 13 such as an anchor.

[0022] The seat belt 4 includes a shoulder belt 4a that restrains the shoulders, chest, etc. of the occupant M, and a lap belt 4b that restrains the waist, etc. of the occupant M. The seat belt 4 is divided by a tongue 6 into the shoulder belt 4a and the lap belt 4b.

[0023] The operation of fastening and unfastening the seat belt 4 in this seat belt device 1 is the same as that of a conventionally known seat belt device.

[0024] The retractor 3 is a winding device that enables winding and unwinding of the seat belt 4, and when acceleration equal to or greater than a predetermined value is detected in an emergency, etc., it restricts the seat belt 4 from being unwound from the retractor 3. The retractor 3 is also provided with a load limiter mechanism (not shown) that keeps the restraining force of the seat belt 4 applied to the occupant M at a constant level.

[0025] The leading end of the seat belt 4 in the withdrawal direction after being withdrawn from the retractor 3 is inserted through the opening of the anchor 5b and connected to the anchor 5b by being folded back and sewn. The anchor 5b is fixed to the seat frame 11 on the opposite side of the vehicle seat 2 from the buckle 7.

[0026] A connecting member 12 that connects the buckle 7 to one seat frame 11 and the tip of the seat belt 4 near the anchor 5b are connected by a tether 10 located below the seat cushion 2b. That is, one end of the tether 10 extending in the left-right direction (widthwise of the seated occupant) below the seat cushion 2b is connected to the connecting member 12, and the other end is connected to the tip of the seat belt 4. For example, both ends of the tether 10 are looped, and the connecting member 12 and the tip of the seat belt 4 are inserted into each loop, thereby connecting the tether 10 to the connecting member 12 and the tip of the seat belt 4. Alternatively, both ends of the tether 10 may be sewn to the connecting member 12 and the tip of the seat belt 4, respectively.

[0027] A pretensioner 8 is connected to the center of the tether 10 in the left-right direction. The pretensioner 8 is activated in the early stages of an emergency, pulling the center of the tether 10 downward or diagonally downward toward the front, thereby increasing the restraining force of the seat belt 4 (particularly the lap belt 4b) on the occupant M.

[0028] In such a seatbelt device 1, in an emergency such as a vehicle collision, when a sensor (not shown) detects acceleration equal to or greater than a predetermined value, the pretensioner 8 is activated and retracts the tether 10 as shown in Fig. 4. By retracting the tether 10, the tip end of the seatbelt 4 and the connecting member 12 are pulled toward the center in the left-right direction of the vehicle seat 2 (seated occupant M) (with a lateral center-side element).

[0029] As a result, the lap belt 4b, tether 10, connecting member 12, and buckle 7 can fasten the lumbar region (pelvis) of the occupant M together with the seat cushion 2b to the vehicle seat in a ring shape. This increases the contact area between the lumbar region of the occupant M and the lap belt 4b, effectively and significantly increasing the restraining force on the lumbar region of the occupant.

[0030] At this time, the tether 10 is moved by the pretensioner 8 until it is positioned below the occupant's waist and seat cushion 2b, but the moved portion generates a reaction force against the downward load generated when the occupant M moves, limiting the downward movement of the waist. Even if the amount of movement of the waist becomes large, the pelvis is held in a ring shape by the seat belt and tether, etc., so the lap belt portion follows the movement and is less likely to come off the pelvis. Furthermore, this seat belt device 1 can effectively restrain the waist of the occupant M in a reclining position.

[0031] As shown in FIG. 5, the tether 10 (first tether) may be inserted into the loop of a looped tether 15 (second tether), and the tether 15 extending in the longitudinal direction of the vehicle may be connected to the pretensioner 8.

[0032] 6, one end of the tether 16 may be fixed to one seat frame 11 (not shown), the tether 16 may be routed around the connecting member 12 and the tip of the seat belt 4 in that order, and the other end of the tether 16 may be connected to the pretensioner 8 near the other seat frame 11 (not shown). The portion of the tether 16 that extends from the one end fixed to one seat frame 11 to the connecting member 12 intersects with the portion that extends from the tip of the seat belt 4 to the other end connected to the pretensioner 8.

[0033] This intersection provides a reaction force against the downward load that occurs when the occupant M moves in an emergency, limiting the downward movement of the lumbar region. Even if the lumbar region moves significantly, the pelvis is held in a ring shape by the seat belt and tether, etc., so the lap belt follows the movement and is less likely to come off the pelvis. Furthermore, this seat belt device 1 can effectively restrain the lumbar region of the occupant M even when the seat is reclined.

[0034] The additional cost is equivalent to that of the pretensioning method of conventional seat belt devices, which pulls the tip of the seat belt 4 or one of the buckles 7, located on both the left and right sides diagonally below and behind the waist of the seated occupant M, diagonally downward and behind the occupant, and is cheaper than the pretensioning method of pulling both the tip of the seat belt 4 and the buckle 7.

[0035] The connecting member 12 and the anchor 5b may be attached to the surface of the seat frame 11 facing either inside or outside the vehicle.

[0036] The buckle 7 and the seat frame 11 may be connected by a connecting member 12 (first connecting member) such as a webbing and a second connecting member (not shown) that is more rigid than the connecting member 12. By using the second connecting member, the position of the buckle 7 can be accurately maintained.

[0037] The retracting portion that retracts the tether 10 is not limited to the pretensioner 8, but may be a motor retractor or the like.

[0038] In the above embodiment, the connecting member 12 and the anchor 5b are fixed to the seat frame, but the fixing point on the vehicle body side may be fixed to the floor or frame of the vehicle body other than the seat frame.

[0039] The above embodiment is merely an example of the present invention, and the present invention may be embodied in a form other than that shown in the drawings. For example, the present invention may be a two-point seat belt device without a shoulder belt, or a multi-point seat belt device with multiple shoulder belts, such as a four-point or more multi-point seat belt device. [Explanation of symbols]

[0040] 1 Seat belt device 2 Vehicle seats 3 Retractor 4 Seatbelts 4a Shoulder belt 4b Lap Belt 5a Guide Anchor 5b Anchor 6 Tongue 7 Buckle 8 Pretensioner 10 Tether

Claims

1. Seat belts and a retractor that winds up the seat belt so that it can be withdrawn; a tongue supported by the seat belt; a buckle to which the tongue is attached and detached; a connecting member that connects the buckle to a seat frame of a vehicle seat or a vehicle body; a tether that connects the connecting member and a leading end of the seat belt in a withdrawal direction below the vehicle seat; a retraction unit that is activated in an emergency to retract the tether; A seat belt device comprising: The direction of retraction of the tether has at least a forward element, A seat belt device in which, by retracting the tether, the connecting member and the tip end of the seat belt are retracted with elements toward the center in the left-right direction of the seated occupant.

2. 2. The seat belt device according to claim 1, wherein the tether has one end connected to the connecting member and the other end connected to the tip end of the seat belt, and extends in the left-right direction of the seated occupant.

3. The tether a first tether having one end connected to the connecting member and the other end connected to the tip portion of the seat belt and extending in the left-right direction of the seated occupant; a second tether having one end connected to the first tether and the other end connected to the retraction portion, the second tether extending in the front-to-rear direction of the seated occupant; 10. The seat belt device of claim 1, further comprising:

4. The vehicle seat further includes a first seat frame and a second seat frame provided on both sides of the vehicle seat in a left-right direction of a seated occupant and extending in a front-rear direction of the seated occupant, The tip end of the seat belt is connected to the first seat frame by an anchor, the buckle is connected to the second seat frame by the connecting member, 2. The seat belt device according to claim 1, wherein one end of the tether is fixed to the first seat frame, is routed from the first seat frame to the connecting member and the tip end of the seat belt in that order, and the other end is connected to the retraction portion on the second seat frame side.

5. 5. The seat belt device according to claim 4, wherein a portion of the tether from the one end to the connecting member intersects with a portion of the tether from the tip end of the seat belt to the other end connected to the retraction portion.

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