JP2024141635A - Occupant restraint system - Google Patents

Abstract

[Problem] To provide an occupant restraint device that can efficiently restrain an occupant and prevent the generation of an excessive occupant restraining force. [Solution] A belt guide 5 is provided on the upper part of the seat back 1b of the seat 1 in which the occupant P sits, which holds the seat belt 2 in a state in which part of it passes near the upper part of the seat back 1b, and a belt retention release mechanism is provided that releases the seat belt 2 held by the belt guide 5 after a pretensioner built into a retractor 3 is activated, thereby increasing the occupant restraining force in the early stage of a collision to efficiently restrain the occupant P, and in the later stage of the collision, the seat belt 2 passes above the position where it was held by the belt guide 5, preventing the generation of an excessive occupant restraining force. [Selected Figure] Figure 4A

Description

This invention relates to an occupant restraint device equipped with a seat belt that restrains an occupant seated in a vehicle seat.

Generally, automobiles and other vehicles are equipped with a three-point seat belt device that serves as an occupant restraint device to prevent occupants from being thrown out of their seats and being injured in the event of a vehicle collision. The three-point seat belt device includes a seat belt that restrains the occupant and a retractor that winds up the seat belt so that it can be withdrawn.

In recent years, in order to further reduce the risk of injury to occupants in the event of a collision, the retractor of the above-mentioned three-point seat belt device is often equipped with a pretensioner that winds up the seat belt to eliminate slack when the vehicle receives an impact. It has also been proposed to provide a belt guide through which the seat belt is inserted at the top of the seat back, and to hold the seat belt in a state in which part of it passes near the upper part of the seat back, thereby enabling high occupant restraint performance in the event of a vehicle collision, etc. (see, for example, Patent Document 1).

JP 2018-58564 A

In a three-point seat belt device equipped with the above-mentioned belt guide, the angle at which the tension of the seat belt acts on the occupant (the angle made by the seat belt bent near the occupant's chest) is smaller than in a conventional structure without a belt guide, and the force restraining the occupant is greater even with the same tension of the seat belt, so the occupant can be restrained more efficiently.

However, if the vehicle receives an impact such as a collision and the pretensioner is activated, and the occupant's upper body leans forward, the force with which the seat belt restrains the occupant increases, and there is a risk that the occupant's chest will be subjected to excessive pressure by the seat belt.

Therefore, the objective of this invention is to provide an occupant restraint device that can efficiently restrain an occupant and prevent the generation of excessive occupant restraint force.

In order to solve the above problems, the passenger restraint device of the present invention includes a seat belt for restraining a passenger seated in a seat having a seat portion and a seat back, a retractor for winding up the seat belt so that it can be withdrawn, a pretensioner that is incorporated in the retractor and winds up the seat belt to eliminate slack in the seat belt when the vehicle receives an impact, a belt guide that is provided on the upper part of the seat back and holds the seat belt in a state in which a portion of the seat belt passes near the upper part of the seat back, and a belt retention release mechanism that releases the seat belt from the state in which it is held by the belt guide after the pretensioner is activated, and adopts a configuration (configuration 1) in which, when the belt retention release mechanism is activated, the seat belt passes above the position where it was held by the belt guide.

In the above configuration 1, the belt retention release mechanism can be configured to operate a predetermined time after the pretensioner is activated (configuration 2).

Alternatively, the belt retention release mechanism can be configured to be activated when a load exceeding a predetermined value acts on the seat belt (Configuration 3).

When the above configuration 3 is adopted, the retractor further includes a load limiter that allows the seat belt to be withdrawn so that the load acting on the seat belt exceeds a predetermined value and the load remains below the predetermined value, and the belt retention/release mechanism can be configured to operate when the load limiter is activated (configuration 4).

In addition, in any of the above configurations 1 to 4, the belt retention release mechanism can separate the belt guide from the seat back (configuration 5).

In addition, in any of the above configurations 1 to 5, a shoulder anchor that is attached to the vehicle above the outer side of the seat in the width direction and supports the seat belt can be adopted, and the seat belt can be pulled upward from the retractor, folded back at the shoulder anchor, and then inserted into the belt guide and held so as to pass near the upper part of the seat back (configuration 6).

By adopting the above configuration, this invention can efficiently restrain the occupant during a vehicle collision, etc., and can prevent the generation of excessive occupant restraint force, so that excessive load is not placed on the occupant.

FIG. 1 is an explanatory diagram of a schematic configuration of an occupant restraint device according to an embodiment of the present invention; FIG. 2 is an explanatory diagram of the occupant restraint force of the occupant restraint device of FIG. 1 immediately after a collision; FIG. 13 is an explanatory diagram of the occupant restraint force of the occupant restraint device of the comparative example immediately after a collision. FIG. 2 is an explanatory diagram of the initial state of the passenger restraint system of FIG. 1 in a collision; FIG. 13 is an explanatory diagram of an initial state of a collision of an occupant restraint device according to a comparative example; FIG. 2 is an explanatory diagram of a post-crash state of the occupant restraint device of FIG. 1; FIG. 13 is an explanatory diagram of a comparative example of an occupant restraint device in a post-crash state;

An embodiment of the present invention will be described below with reference to the drawings. As shown in FIG. 1, the passenger restraint device of this embodiment is a three-point seat belt device that includes a seat belt (webbing) 2 that restrains an occupant P seated in a seat 1 having a seat portion 1a and a seat back 1b, an anchor (not shown) that is fixed to the outer side of the seat 1 in the width direction and to which one end of the seat belt 2 is connected, a retractor 3 that winds up the other end of the seat belt 2 so that it can be withdrawn, and a D-ring-shaped shoulder anchor 4 that is attached to the vehicle above the outer side of the seat 1 in the width direction and supports the seat belt 2.

The seat belt 2 is pulled upward from the retractor 3 and folded back at the shoulder anchor 4, and then passed through a belt guide 5 provided at the upper part of the outer width of the seat back 1b. A tongue plate (not shown) attached to the seat belt 2 fits into a buckle 6 provided on the inner width of the seat bottom 1a of the seat 1, thereby restraining the occupant P at the part extending from one shoulder of the occupant P (the outer width of the seat 1) to the other waist (the inner width of the seat 1) and at the part extending laterally along the waist of the occupant P.

The retractor 3 is attached to the vehicle below the shoulder anchor 4, and incorporates a pretensioner and a load limiter (both not shown). The pretensioner winds up the seat belt 2 to eliminate slack in the seat belt 2 when the vehicle receives an impact. The load limiter allows the seat belt 2 to be pulled out so that the load remains below a predetermined value when the load acting on the seat belt 2 exceeds a predetermined value after the pretensioner is activated.

The belt guide 5 is for holding the seat belt 2 with a portion of it passing near the upper portion of the seat back 1b, but as described below, it is designed to separate from the seat back 1b when certain conditions are met. In other words, in this embodiment, a belt retention release mechanism is provided that separates the belt guide 5 from the seat back 1b and releases the seat belt 2 from its retention by the belt guide 5.

The occupant restraint device of this embodiment has the above-mentioned configuration, and its operation during a vehicle collision will now be described with reference to Figures 2A to 4B. In explaining this operation, the occupant restraint device of the above-mentioned configuration is used as an example (Figures 2A, 3A, and 4A), and an occupant restraint device of a conventional structure is used as a comparative example (Figures 2B, 3B, and 4B), and the differences in operation between the two will be described. The only structural difference between the example and the comparative example is the presence or absence of the belt guide 5 described above.

When the vehicle collides, as shown in Figs. 2A and 2B, in both the embodiment (Fig. 2A) and the comparative example (Fig. 2B), a signal is sent from a sensor (not shown) to the retractor 3, which activates the pretensioner, and the seat belt 2 is wound up by the retractor 3 so that there is no slack. As a result, the occupant P is pressed against the seat back 1b.

In this embodiment, the seat belt 2 is held by the belt guide 5 in a state where it passes near the upper part of the seat back 1b, so compared to the comparative example in which the seat belt 2 passes higher, the angle at which the tension of the seat belt 2 acts on the occupant P (the angle made by the seat belt 2 bent near the chest of the occupant P) is smaller, and even if the tension of the seat belt 2 is the same, the resultant tension force, i.e., the force (occupant restraining force) F that restrains the area near the chest of the occupant P, is larger.

For this reason, as shown in Figures 3A and 3B, in the early stages of the collision, the upper body of the occupant P subjected to the inertial force tilts forward less in the example (Figure 3A) than in the comparative example (Figure 3B), and the tip position a1 of the head of the occupant P in the example remains further rearward than the tip position b1 of the head of the occupant P in the comparative example.

Then, the load acting on the seat belt 2 increases due to the forward movement and upper body tilt of the occupant P in the early stages of the collision, and when the load exceeds a predetermined value, the load limiter of the retractor 3 is activated. The period after the load limiter is activated is called the later stage of the collision.

In the later stages of the collision, in this embodiment, as shown in FIG. 4A, when the load limiter is activated, the belt retention release mechanism operates, the belt guide 5 separates from the seat back 1b, the belt guide 5 releases the seat belt 2 from its retention, and the seat belt 2 passes above the position where it was retained by the belt guide 5.

As a result, in the later stages of the collision, as shown in Figures 4A and 4B, the angle at which the tension of the seat belt 2 acts on the occupant P in the Example (Figure 4A) is about the same as in the Comparative Example (Figure 4B). In both the Example and the Comparative Example, the seat belt 2 is pulled out from the retractor 3 by the action of the load limiter, causing the occupant P's upper body to lean forward more, but the head tip position a2 of the occupant P in the Example remains further rearward than the head tip position b2 of the occupant P in the Comparative Example. The difference in head tip positions (b2-a2) is approximately the same as the difference in head tip positions (b1-a1) at the beginning of the collision.

In other words, in the occupant restraint device of the embodiment, the occupant restraint force in the later stages of the collision is the same as in the comparative example, but the occupant restraint force in the early stages of the collision is greater than in the comparative example, so that the inclination of the upper body of the occupant P (displacement of the upper body relative to the vehicle) can ultimately be suppressed more effectively than in the comparative example. Therefore, the head of the occupant P can be prevented from contacting interior components (dashboard, etc.) more reliably than in the comparative example.

Moreover, in the later stages of the collision when the load acting on the seat belt 2 becomes large, the belt guide 5, which improves the occupant restraint performance, separates from the seat back 1b, preventing the generation of excessive occupant restraint force. Specifically, the force restraining the occupant P near the chest is about the same as in the comparative example, so the occupant P's chest is not excessively compressed by the seat belt 2, and the load on the occupant P can be kept to the same level as in the comparative example.

The belt retention release mechanism can be composed of, for example, a locking device that locks the belt guide 5 in a fixed state to the seat back 1b, and an actuator that unlocks the locking device upon receiving a signal from the airbag control device. When the actuator releases the locked state of the belt guide 5, the tension of the seat belt 2 causes the belt guide 5 to be pulled up and separated from the seat back 1b, and the retention state of the seat belt 2 is also released.

The belt retention release mechanism is not limited to one that separates the belt guide from the seat back as in the embodiment, but may be configured so that the seat belt is released from the belt guide. For example, a configuration in which the belt guide breaks when a load exceeding a predetermined value acts on the seat belt can be adopted.

In the above embodiment, the belt retention release mechanism is activated when the load limiter is activated, but the timing of the belt retention release mechanism can be set to any appropriate timing after the pretensioner is activated. For example, it may be activated after a predetermined time (approximately 0.05 to 0.07 seconds) has elapsed since the pretensioner is activated, or when a load exceeding a predetermined value is applied to the seat belt.

In the above-described embodiment, the occupant restraint force at the beginning of the collision is made larger than in the comparative example, thereby reducing the final displacement of the occupant's upper body. However, it is also possible to use the seat belt load setting at which the load limiter is activated lower by an amount equivalent to the effect of increasing the occupant restraint force at the beginning of the collision, thereby reducing the load on the occupant compared to the comparative example while keeping the displacement of the occupant's upper body to the same level as in the comparative example.

The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. Therefore, the scope of the present invention is indicated by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims.

1 Seat 1a Seat 1b Seat back 2 Seat belt 3 Retractor 4 Shoulder anchor 5 Belt guide 6 Buckle P Occupant

Claims (6)

a seat belt for restraining an occupant seated in a seat having a seat portion and a seat back;
a retractor that winds up the seat belt so that the seat belt can be withdrawn;
a pretensioner incorporated in the retractor for winding up the seat belt to eliminate slack in the seat belt when the vehicle is subjected to an impact;
a belt guide provided on an upper portion of the seat back and configured to hold the seat belt such that a portion of the seat belt passes near an upper portion of the seat back;
a belt retention release mechanism that releases the seat belt from a retained state by the belt guide after the pretensioner is activated;
Equipped with
When the belt retention release mechanism is activated, the seat belt passes above the position where it was retained by the belt guide. The passenger restraint device according to claim 1, wherein the belt retention release mechanism operates a predetermined time after the pretensioner is activated. The occupant restraint device according to claim 1, wherein the belt retention release mechanism is activated when a load exceeding a predetermined value acts on the seat belt. The retractor further includes a load limiter that allows the seat belt to be withdrawn so that the load applied to the seat belt is kept below a predetermined value when the load exceeds a predetermined value,
4. The passenger restraint device according to claim 3, wherein the belt retention release mechanism is actuated when the load limiter is activated. The occupant restraint device according to any one of claims 1 to 3, wherein the belt retention release mechanism separates the belt guide from the seat back. A shoulder anchor is provided which is attached to a vehicle above an outer side of the seat in a width direction and supports the seat belt,
4. An occupant restraint device according to claim 1, wherein the seat belt is pulled upward from the retractor, folded back at the shoulder anchor, and then inserted through the belt guide and held so as to pass near the upper portion of the seat back.

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