JP2002067875A - Seat belt tension detecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a seat belt tension detecting device capable of preventing malfunction of an airbag. SOLUTION: This seat belt tension detecting device is used for a seat belt device equipped with a webbing W to restrain the body of an occupant in a seat and a retractor 13 to withdrawably take up the webbing W. The device is equipped with a tension detecting means 15 to detect that tension of not less than prescribed one is applied on the webbing W, and a control means not to actuate an airbag based on the condition of the tension detecting means 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seat belt tension detecting device used for a seat belt device mounted on a vehicle such as an automobile.

[0002]

2. Description of the Related Art FIG. 12 shows a three-point seat belt device 90 conventionally mounted on an automobile. In the three-point seat belt device 90, the webbing 91 has one end wound around the retractor 100 so as to be able to be pulled out, the other end inserted into the through anchor 94 and the sluting 96 supported by the center pillar 98, and fixed to the vehicle body. It is locked on an anchor plate 97. Seat belt device 9
In use, the occupant engages the slutung 96 with the buckle 93 provided on the seat 95 on the side opposite to the anchor plate 97 side. As a result, the webbing 91 traverses obliquely downward in front of the seat back 95a, and is folded back by the sluting 96 to traverse the front of the seat back 95a substantially horizontally along the base end of the seat back 95a (see FIG. 12). State), and the occupant seated on the seat 95 is restrained.

[0003] A child seat 110 may be attached to the passenger seat 95 in some cases. Insertion hole 112 provided in base 111 of child seat 110
And a part of the webbing 91 is inserted into the
The child seat 110 can be mounted on the seat 95 by engaging the buckle 93 with the 6. The sheet 95
Can be moved back and forth by removing a seat slide lock device (not shown) provided at the lower part of the seat 95, and by moving the seat 95 forward, the child seat 110 can be moved by the webbing 91 to the seat 9.
5 can be tightened.

[0004] Recent automobiles are equipped with an SRS airbag (not shown) that swells between the occupant and the interior wall of the vehicle and catches the occupant's body in the event of a vehicle emergency such as a collision. In response to this, measures have been taken to improve occupant safety. The airbag is electrically or mechanically activated when a large acceleration acts on the vehicle due to a collision or the like. Generally, the airbag can be activated only when an occupant (adult) of a predetermined size or more sits on the seat 95. The seat 95 is provided with a predetermined detecting means such as a weight sensor for detecting that an adult is seated.

[0005]

Conventionally, it has been desired that the airbag does not operate when the child seat 110 is mounted on the passenger seat 95. However, the child seat 110 is attached to the seat 95 by webbing of the seat belt device in the above-described method or the like.
When the body is tightened extremely tightly, the weight sensor and other sensors mistakenly judge that an adult is sitting on the seat,
It is conceivable that the airbag can be operated, and it is required to eliminate such erroneous determination.

[0006] The present invention has been made in view of the above circumstances, and an object of the present invention is to prevent an airbag from becoming operable in a situation where it is not necessary to operate the airbag. To provide a seat belt tension detecting device.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to detect a seat belt tension used in a seat belt apparatus provided with a webbing for restraining an occupant's body to a seat, and a retractor for retractably winding the webbing. An apparatus for detecting seat belt tension, comprising: tension detecting means for detecting that a predetermined or more tension acts on the webbing; and control means for disabling an airbag based on a state of the tension detecting means. Can be achieved by the device.

According to the seat belt tension detecting device as described above, it is determined whether or not the tension is applied to the webbing or more than a predetermined time, such as when the child seat is tightly fastened to the seat. Can be detected by the tension detecting means. Also, in the event of a vehicle emergency such as a collision, the webbing is subjected to a tension higher than a predetermined value.In this case, the action time of the force exceeding the predetermined value and other conditions may cause the child seat to be tightly fastened to the seat by the webbing. Different from non-emergency cases. Therefore, in a preferred configuration of the present invention, based on the difference in the time of action of the force and other conditions in the case of a vehicle emergency and other cases,
When it is detected that the webbing has been subjected to a predetermined tension or more and is not in the emergency of the vehicle, the control means prohibits the operation of the airbag. By using this seat belt tension detecting device, it is possible to reliably prevent the airbag from being operable in the seat on which the child seat is mounted.

Preferably, the tension detecting means includes a pressing member that contacts the webbing, an urging member that urges the pressing member to press and displace the webbing by the pressing member, and that the tension of the webbing is a predetermined value. A switch means can be provided which is switched by the movement of the pressing member accompanying the return of the displacement of the webbing at the time of the above.

Preferably, the tension detecting means is configured to apply a wave such as a sound wave to the webbing and detect a reflection state of the wave to obtain a tension of the webbing.

Preferably, the tension detecting means includes an engaging member engaged with the webbing, a fixing member fixing the engaging member to the seat or a vehicle body to which the seat is attached, and the engaging member. Switch means interposed between the fixing member and the fixing member, the switching means being switched by the movement of the engaging member when the tension of the webbing becomes a predetermined value or more.

Preferably, the tension detecting means includes seat switch means for detecting that an occupant of a predetermined size or more is seated on the seat, and buckle switch means for detecting that the webbing is engaged with a buckle. When,
Tension switch means for detecting that a predetermined or more tension is applied to the webbing; and a predetermined or more tension than the webbing other than in a vehicle emergency based on the states of the seat switch means, the buckle switch means and the tension switch means. And a judging means for judging that the operation has been performed.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. In the embodiments described below, the members and the like having the same configurations and operations as the members and the like already described are denoted by the same reference numerals or corresponding reference numerals in the drawings, and the description thereof will be simplified or omitted.

FIG. 1 shows a retractor provided with a first embodiment of the present invention. The retractor 10 has a webbing W
Is provided with a substantially cylindrical bobbin 13 wound so as to be able to be pulled out, and a substantially U-shaped retractor base 11 in which side plates 11b and 11c are raised from a back plate 11a. Bobbin 13
Is rotatably bridged between the side plates 11b and 11c. A known emergency locking means 20 for preventing the bobbin 13 from rotating in the webbing withdrawing direction in the event of a vehicle emergency is provided outside one (right side in the figure) side plate 11c. Outside the other (left side in the figure) side plate 11b, a known pretensioner 21 that rotates the bobbin 13 to tighten the webbing W by rotating the bobbin 13 so as to remove the slack of the webbing W that restrains the occupant in the event of a vehicle emergency, A known take-up spring device 22 that constantly urges the bobbin 13 in the webbing take-up direction is provided. Although not shown, the winding shaft penetrates the center of the bobbin 13 in the axial direction and is integrally connected to the bobbin 13. In a vehicle emergency, the winding shaft is prevented from rotating by the emergency locking means 20 and the pretensioner 21. Or rotated in a predetermined direction. The winding shaft may absorb impact energy by torsional deformation. In this case, the winding shaft, the emergency locking means 20, and the like constitute an energy absorbing mechanism.

The back plate 11a of the retractor base 11 is extended in a webbing pull-out direction (upward in the drawing), and a bent portion (webbing guide) 11 is formed at the extended portion.
d is formed. The bent portion 11d is made of a webbing W
Extending in a direction crossing the An elongated belt slot 11e into which the webbing W is inserted is provided in the bent portion 11d.
Is provided. An upper stay 11f is connected to the bent portion 11d.

FIG. 2 is a side view of the retractor when the winding spring device 22 is removed from the retractor 10 of FIG. As shown in FIG. 2, near the belt slot 11e above the retractor base 11 in the drawing, a tension detecting means 1 for detecting that a predetermined or more tension acts on the webbing W.
5 are provided. The tension detecting means 15 is turned on / off by a lever member 16 as a pressing member and a pressing member.
Limit switch 18 as switch means to be turned off
And The lever member 16 includes a pair of side plates 16a having one ends (lower ends in the drawing) rotatably fixed to the back plate 11a of the retractor base 11, and a connecting plate 16b connecting the other ends (upper ends in the drawing) of the side plates 16a. Back plate 1 with which arm (movable part) 18a of limit switch 18 contacts
6c. A second belt slot 17 is provided in the connecting plate 16b. The limit switch 18 shown in FIG. 2 is in an off (on) state. Although not shown, a timer means for detecting that the ON state (OFF state) of the limit switch 18 has continued for a predetermined time, and a control means for disabling the airbag based on the states of the timer means and the tension detecting means 15 are also provided. , Is provided in the present embodiment. The seat belt tension detecting device according to the present embodiment includes:
It is composed of these timer means, tension detecting means 15 and control means.

FIG. 2 is a cross-sectional view taken along the line III-III in FIG.
Is shown in FIG. In FIG. 3, illustration of the webbing W is omitted. As shown in FIG. 3, one side plate 1 of the lever member 16 is provided.
A locking projection 16d is provided on the outer surface of 6a, and a torsion coil spring (hereinafter, referred to as "spring") 19 as an urging member is engaged with the locking projection 16d. 3, the second belt slot 17 provided in the connecting plate 16b of the lever member 16 does not overlap with the belt slot 11e of the retractor base 11, and they are offset in the rotation direction of the lever member 16. are doing.

Hereinafter, the tension detecting means 1 in this embodiment will be described.
The operation of No. 5 will be described. FIG. 4 is a schematic diagram showing a state in which the webbing W pulled out from the bobbin 13 is inserted into the belt slot 11 e of the retractor base and the second belt slot 17 of the lever member 16, and the webbing W is wrapped around the through anchor 94. It is. Lever member 1
The rotation shaft 16 is driven by a spring 19 (see FIG. 3).
The webbing W inserted in the second belt slot 17 is urged in the counterclockwise direction in the drawing around the center e, and the inner surface (second sliding contact surface) of the second belt slot 17 moves leftward in the drawing. Is pressed and displaced. That is, the bobbin 13
An intermediate portion of the webbing W stretched between the webbing W and the through anchor 94 is pressed and displaced by the lever member 16 to the left in the drawing. Thereby, the webbing W is separated from the inner surface (sliding contact surface) of the belt slot 11e of the retractor base. When the occupant is normally restrained by the webbing W, the state shown in FIG. 4 is obtained. Hereinafter, this is referred to as a normal use state. In a normal use state, the tension acting on the webbing W is small (about 1N).

On the other hand, when the child seat is mounted on the sheet using the webbing W, a large tension is applied to the webbing W (for example, a tension 10 times or more that of a normal use state;
A tension of about 200N. ) Works. Then, as shown in FIG. 5, the displacement of the webbing W pressed and displaced by the lever member 16 is restored. That is, the webbing W rotates the lever member 16 in the clockwise direction in the figure against the urging force of the spring 19 (see FIG. 3). At this time, as shown in FIG.
Arm 18a is also moved, and the limit switch 18 is switched. The webbing W has a second belt slot 17.
And the inner surface of the belt slot 11e.

The emergency lock means 20 (see FIG. 1) is activated not only when the child seat is mounted on the seat but also when the occupant is restrained by the webbing W in the event of a vehicle collision, sudden braking, light collision, or the like. The webbing W is tensioned by the occupant moving forward. That is, high tension acts on the webbing. Hereinafter, this is referred to as a normally used high tension state. However, the time during which the tension acts at this time is shorter than the time during which the tension acts on the webbing W when the child seat is mounted on the sheet.

The seat belt tension detecting device according to the present embodiment is different from the above-described tension detecting means 15 in that the switch is not switched unless a predetermined or more tension is applied to the webbing W (for example, ten times or more the tension in a normal use state). Also, a timer means is provided. This timer means detects that the ON state of the limit switch 18 has continued for a predetermined time. Therefore, according to the seatbelt tension detecting device of the present embodiment, it is possible to detect that the tension of the predetermined or more continuously and for a long time (1 minute or more) acts on the webbing W continuously for a predetermined time, such as when a child seat is worn, The used high tension state can be reliably distinguished from the case where the child seat is mounted on the passenger seat by webbing. Then, when the child seat is mounted on the passenger seat, the malfunction of the airbag can be prevented by the control means.

FIG. 6 shows a retractor provided with a second embodiment of the present invention. In the present embodiment, the tension detecting means 15 provided near the retractor (the webbing outlet of the retractor) in the above-described first embodiment is changed, and the other configuration can be the same as that of the first embodiment. . In the present embodiment, the tension detecting means 35 for detecting that a predetermined or more tension has acted on the webbing other than during a vehicle emergency includes an oscillator 35a, a receiver 35b, and a base 35c on which these are mounted. Tension detecting means 35
Here, is provided on an upper stay 11f extending along the webbing W inserted through the belt slot 11e.

The oscillator 35a emits a vibration such as a sound wave toward the webbing W. The vibration is reflected by the webbing W, but when the tension of the webbing W is low, the vibration is largely absorbed by the webbing W and the vibration is attenuated. Then, the vibration reflected from the webbing W is received by the receiver 35b, and the amplitude and the like of the waveform of the received vibration are observed by observation means (not shown), so that the webbing W
To get the tension.

The seat belt tension detecting device of this embodiment includes, in addition to the tension detecting means 35 and the observation means described above, a timer means for detecting that a predetermined or more tension acts on the webbing W for a predetermined time, Control means for deactivating the airbag based on the state of the means, the observation means and the tension detecting means 35 means. According to the seat belt tension detecting device of the present embodiment, the tension detecting means 35 can be easily attached irrespective of the difference in the shape of the retractor 30 according to the applied vehicle type, except for a vehicle emergency except a normal use high tension state. Can be reliably detected that a predetermined or more tension acts on the webbing W.

FIG. 7 shows a vehicle seat 95 and a seat belt device 40 provided with a third embodiment of the present invention. One end of the webbing W of the three-point seat belt device 40 is wound around a retractor (not shown) so as to be able to be pulled out, and the other end is inserted through a through anchor and a sluting 96 (not shown), and is also engaged with an anchor plate 97 fixed to the vehicle body. Have been. The anchor plate 97 is fixed to the vehicle body by an anchor bolt 99 penetrating therethrough. A buckle 93 is provided on the opposite side of the seat 95 from the anchor plate 97. Buckle 93
It is connected to one end of an anchor member 47 as an engaging member. The other end of the anchor member 47 is fixed to the fixing plate 50 by an anchor bolt 49 as a fixing member penetrating therethrough. The fixing plate 50 is fixed to the vehicle body. When the slutung 96 is engaged with the buckle 93, a tension equivalent to the tension acting on the webbing W acts on the anchor member 47.

FIG. 8 is a sectional view of a fixing structure of the anchor member 47 and the fixing plate 50. As shown in FIG. 8, the anchor member 47 has a through hole 47a. Through hole 4
A burring process is performed on a rear side (lower side in the figure) of the peripheral edge portion 7a as viewed in a direction in which the anchor member 47 is pulled to form a pressing portion 47b. Through hole 47
The shaft portion of the anchor bolt 49 penetrates a. The shaft portion of the anchor bolt 49 also penetrates the fixing plate 50 which is disposed adjacent to the anchor member 47 via the plain washer 52. A fixing plate 50 is provided on the shaft of the anchor bolt 49.
On the side opposite to the anchor member 47 side of the weld nut 51
Is screwed. Weld nut 51 is welded to fixing plate 50.

The shaft of the anchor bolt 49 is provided with a fixing plate 5.
The bush 53 is externally fitted on the side of the anchor member 47 of No. 0. A ring-shaped rubber switch 55 is fitted around the outer periphery of the bush 53. The outer peripheral surface of the rubber switch 55 is in contact with the inner peripheral surface of the through hole 47a of the anchor member 47 and the inner peripheral surface of the pressing portion 47b. In other words, the rubber switch 55 is interposed between the anchor bolt 49 and the anchor member 47. Anchor member 4 of rubber switch 55
The signal line 55c protrudes from the outer peripheral surface on the side (upper side in the figure) not facing the pressing portion 47b of No. 7. The tension detecting means 45 in the present embodiment includes the anchor member 47, the anchor bolt 49, the fixing plate 50, the rubber switch 55, and the like.

FIGS. 9A and 9B are views for explaining the configuration of the rubber switch 55. FIG. 9A is a perspective view, and FIG.
FIG. 3C is a cross-sectional view illustrating a state where the rubber switch 55 is turned on. As shown in FIG. 9B, an outer peripheral terminal (one terminal) 55a and an inner peripheral terminal (the other terminal) 55b are embedded in the rubber switch 55 at an interval. As shown in FIG. 9 (C), an external force F acts on the rubber switch 55 to
When the inner terminal 5b and the inner peripheral terminal 55b approach each other, the rubber switch 55 is turned on.

Returning to FIG. When the child seat is mounted on the seat 95 using the webbing W, the webbing W
8, the anchor member 47 is pulled in the direction of arrow F in FIG. At this time,
The pressing portion 47b of the anchor member 47 crushes the rubber switch 55 between the bush 53 and the rubber switch 55. Thus, the rubber switch 55 is turned on.

The seat belt tension detecting device according to the present embodiment includes, in addition to the above-described tension detecting means 45, a timer means for detecting that a predetermined or more tension is applied to the webbing W for a predetermined time, There is also provided control means for stopping the operation of the airbag based on the state of the detection means 45 means. According to the seat belt tension detecting device of the present embodiment, while using a conventional retractor, it is ensured that a predetermined or more tension has acted on the webbing W other than during a vehicle emergency except a normal use high tension state. Can be detected. In this embodiment, the buckle 93
Although the tension detecting means 45 is provided in the fixing structure of the anchor member 47 connected to the webbing W, the detecting means may be provided in the fixing structure of the anchor plate 97 connected to the webbing W or the through anchor (not shown).

FIG. 10 is a block diagram showing the electrical configuration of the fourth embodiment of the present invention. The seat belt tension detecting device is controlled by a central processing unit (hereinafter, referred to as “CPU”) 51. The CPU 51 has a buckle switch 5
2. The seat switch 53, the tension switch 55 and the like are connected via the input / output interface 54. Also C
To the PU 51, a memory 56, a timer 57, an operation prohibition unit 58 for disabling the operation of the airbag, and the like are connected.

The buckle switch 52 detects that the through anchor into which the webbing has been inserted is engaged with the buckle. The seat switch 53 detects that an adult is seated on the seat (detects that an object weighing 30 kg or more is placed on the seat). The tension switch 55 detects that a predetermined or more tension acts on the webbing, and may use, for example, the tension detecting means 15, 35, 45 in the first to third embodiments described above. CPU
51 is a buckle switch 52, a seat switch 53,
Based on the state of the tension switch means 55, the timer 57, and the like, processing such as judging that a predetermined or more tension has acted on the webbing other than in an emergency of the vehicle is performed. The processing program and various data are stored in the memory 56. If the CPU 51 determines that a predetermined or more tension has acted on the webbing other than during a vehicle emergency, the operation prohibition unit 58
To deactivate the airbag.

An example of the processing procedure by the CPU 51 is shown in FIG.
Shown in In step 61, it is detected whether the slutung is engaged with the buckle and the buckle switch is turned on. When the buckle switch is turned on, step 62
Then, it is detected whether or not the adult is seated on the seat and the seat switch 62 is turned on. When the sheet switch is turned on, in step 63, it is detected whether or not a tension greater than a predetermined value acts on the webbing and the tension switch is turned on. When the tension switch is turned on, in step 64, the tension switch is turned on for a predetermined time T (for example, 60 seconds to 300 seconds).
Second) to determine whether or not it has continued. If it is determined that the tension switch has been on for a predetermined time T, it is determined in step 65 that the child seat is mounted on the seat by webbing. If so, the operation of the airbag is prohibited. If it is detected that the seat switch is turned on in step 67 without the buckle switch being turned on in step 61, then in step 68,
It detects whether the buckle switch has been turned on. If the buckle switch is turned on after the seat switch is turned on, it is detected in step 69 whether or not the tension switch is in the off state. If the tension switch is off, it is determined in step 70 that an adult is seated on the seat. If so, the airbag becomes operable.

According to the seat belt tension detecting device of the present embodiment, whether the webbing is subjected to a predetermined tension or more when an adult is seated on the seat, or the predetermined tension is applied to the webbing when the child seat is mounted on the seat. Can be determined accurately. Step 63, step 64, and step 69 shown in the present embodiment can be omitted.

[0035]

As described above, by using the seat belt tension detecting device of the present invention, it is possible to reliably prevent the air bag from malfunctioning except in an emergency of the vehicle.

[Brief description of the drawings]

FIG. 1 is a front view of a retractor 10 using a first embodiment of the present invention.

FIG. 2 is a schematic side view when the take-up spring device 22 is removed from the retractor of FIG.

FIG. 3 is a sectional view taken along the line III-III in FIG. 2;

FIG. 4 is a diagram illustrating the operation of the first embodiment.

FIG. 5 is a diagram illustrating the operation of the first embodiment.

FIG. 6 is a schematic side view of a retractor 30 using a second embodiment of the present invention.

FIG. 7 is a front view showing a seat and a seatbelt device using a third embodiment of the present invention.

FIG. 8 is a sectional view showing a schematic configuration of a third embodiment.

9 is a diagram illustrating a rubber switch 55 in FIG.

FIG. 10 is a block diagram showing an electrical schematic configuration of a fourth embodiment of the present invention.

FIG. 11 is a flowchart illustrating the operation of the fourth embodiment.

FIG. 12 is a diagram illustrating how a child seat is mounted on a passenger seat.

[Explanation of symbols]

 10, 30 retractor 11 retractor base 11d bent portion (webbing guide) 11e belt slot 13 bobbin 15, 35 tension detecting means 16 lever member (pressing member) 18 limit switch (switch means) 94 through anchor W webbing

Claims (1)

[Claims] 1. A seatbelt tension detecting device used in a seatbelt device comprising: a webbing for restraining an occupant's body to a seat; and a retractor for winding up the webbing so that the webbing can be pulled out. A seat belt tension detecting device, comprising: tension detecting means for detecting that the webbing has been actuated; and control means for stopping the operation of the airbag based on the state of the tension detecting means.