JP2005219535A - Seat belt device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately determine the suspension of the withdrawal regardless of the seat belt withdrawal process by the occupant and to wind the belt, thereby preventing the occupant from feeling uncomfortable due to an unnecessary increase in the belt tension and the commercial value. Provided is a seat belt device capable of improving the performance.
The rotation of a spool 3 accompanying the withdrawal of the seat belt 4 is detected by a rotation speed sensor 12, and the subsequent wearing of the seat belt 4 is detected by a buckle switch 25. If the buckle switch 25 does not turn on even after a required wearing time To that allows for a general required time required for belt wearing after the rotation sensor 12 detects the withdrawal of the seat belt 4, the belt Assuming that the withdrawal is interrupted, the spool 3 is rotated by the motor 11 and the seat belt 4 is wound up.
[Selection] Figure 1

Description

  The present invention relates to a seat belt device installed in a vehicle, and more particularly to control of belt tension.

  A seat belt device installed in a vehicle plays a role of restraining a passenger from jumping out of a seat by restraining an occupant with the seat belt when a large deceleration acts on the vehicle due to a collision or the like. In this type of seat belt device, the occupant pulls out and uses the seat belt wound around the retractor as needed, and belt tension is always applied to the seat belt by the retractor. The seat belt can be wound and the seat belt is prevented from slacking during use. The optimum belt tension by the retractor varies depending on the use situation of the seat belt.For example, when the buckle is disassembled, a relatively strong belt tension is required for smooth winding. A relatively weak belt tension is required to alleviate. Therefore, a seat belt device has been proposed in which the belt tension by the retractor is adjusted according to such a use situation (see, for example, Patent Document 1).

In the seat belt device disclosed in Patent Document 1, the belt tension for selectively acting two types of spiral springs having different urging forces according to the switching of the solenoid is adjusted, and the retracted state of the belt in the retractor and the belt withdrawal Sometimes, the belt tension is weakened, and when buckle fastening is detected by a switch provided on the buckle, the belt tension is weakened after the belt tension is once increased to eliminate the looseness of the seat belt. If the seat belt is pulled out for a predetermined time (for example, 0.5 sec), this situation is detected based on the amount of rotation of the reel for winding the belt, and the belt is pulled out by increasing the belt tension. The belt tension is again weakened based on the reel rotation amount when the withdrawal of the interrupted belt is resumed while the seat belt is being taken up.
JP 2000-135969 A

  However, the process from when the occupant starts to pull out the seat belt until it is fastened to the buckle varies depending on the person's heel and the surrounding conditions. When the user is distracted by the conversation with the passenger, the belt pulling operation is temporarily interrupted due to lack of smoothness. In the seat belt device disclosed in the above-mentioned Patent Document 1, since it is a condition that the belt withdrawal is interrupted for a predetermined time, the belt tension is unnecessarily increased in spite of the intention to wear the belt in such a case. As a result, the passenger feels uncomfortable, and as a result, the commercial value of the seat belt device is lowered.

  The object of the present invention is to accurately determine the suspension of the withdrawal regardless of the seat belt withdrawal process by the occupant and to wind the belt, thereby preventing the passenger from feeling uncomfortable due to an unnecessary increase in belt tension. An object of the present invention is to provide a seat belt device capable of improving the commercial value.

  In order to achieve the above object, the invention of claim 1 is directed to a rotating body that is fixed to one end of a seat belt and rotated so that the seat belt can be wound, and a biasing force that urges the rotating body in the seat belt winding direction. In a seat belt device having a biasing member and a motor belt mechanism capable of rotating a rotating body in a winding direction by a rotational force of a motor, belt withdrawal detecting means for detecting a seat belt withdrawal state, and a seat belt wearing state Motor rotation control means for detecting belt wear detection means for detecting, and motor rotation control means for controlling the rotational force of the motor belt mechanism acting on the rotating body according to the detection results of the belt withdrawal detection means and the belt wear detection means. Even if a predetermined time elapses after the seat belt is pulled out by the belt pull-out detection means and the belt wearing detection means, the seat bell There when it is detected a predetermined state which is not worn, it actuates the motor of the motor belt mechanism to rotate in the winding direction of the rotating body.

  Accordingly, when the withdrawal of the seat belt is started, the withdrawal of the belt is detected by the belt withdrawal detection means, and when the belt is worn thereafter, the wearing of the belt is detected by the belt wearing detection means. And, when the seat belt is left in the middle of the withdrawal, allowance is made for a predetermined time after the detection of the withdrawal of the seat belt by the belt withdrawal detection means, for example, a general required time required for wearing the belt. Even if time elapses, the seat belt wearing detection means does not detect the seat belt wearing, so the motor rotation control means operates the motor of the motor belt mechanism, and the rotating body rotates in the winding direction to ensure the seat belt. It is wound up.

  Here, the belt pull-out operation may be interrupted despite the willingness to wear the belt due to the occupant's heel or surrounding conditions, but based on the time from the start of belt pull-out to the completion of wear. Therefore, even if the belt pull-out operation is interrupted to some extent, the time required for wearing the belt as a whole is not extended so much, and the belt wearing is completed before a predetermined time elapses. Therefore, when the occupant is willing to wear the belt in this way, a situation in which the belt tension is unnecessarily increased is prevented.

According to a second aspect of the present invention, in the first aspect, the motor rotation control means stops the operation of the motor when the belt drawing-out detection means detects completion of winding of the belt after the motor has rotated in accordance with the detection of the predetermined state. It is something to be made.
Accordingly, when the belt drawing detection means detects the completion of the winding of the belt after the motor has been rotated in accordance with the detection of the predetermined state, the motor operation is stopped by the motor rotation control means, and the seat belt is normally wound. Return to the completed state.

According to a third aspect of the present invention, in the first or second aspect, the belt pull-out detection unit is configured to remove the seat belt from the retracted state, the rotational position of the rotating body, the amount of winding of the seat belt by the rotating body, or the seat The pulled-out state of the seat belt is detected according to any of the tensions relating to the belt.
Therefore, the seat belt pull-out amount, the rotational position of the rotating body, the amount of winding by the rotating body, and the tension related to the seat belt all change according to the state of the seat belt being pulled out. It becomes possible to detect the pulled-out state.

  As described above, according to the seat belt device of the first to third aspects of the present invention, it is possible to accurately determine the suspension of the withdrawal regardless of the seat belt withdrawal process by the occupant and to wind the belt. It is possible to prevent the passenger from feeling uncomfortable due to an increase in belt tension and improve the product value.

Hereinafter, an embodiment of a seat belt device embodying the present invention will be described.
FIG. 1 is an overall configuration diagram showing a seat belt device of the present embodiment, and FIG. 2 is a partial sectional view of the retractor as seen from the front of the vehicle. Although FIG. 1 shows a seat belt device for one seat, a seat belt device having the same configuration corresponding to another seat provided in the vehicle is also connected to the control circuit in the drawing.

  The retractor 1 of the seat belt device is fixed, for example, near the lower portion of the center pillar 2 of the vehicle, and is hidden from the vehicle interior by an interior material (not shown) attached to the center pillar 2. A spool 3 (rotary body) is rotatably provided in the retractor 1 by a rotating shaft 3 a, and one end of a seat belt 4 is fixed to the spool 3. A spiral spring (biasing member) (not shown) is mounted on the spool 3, and the spool 3 is always biased in the winding direction of the seat belt 4 (the arrow direction in FIG. 2) by the spiral spring. Although not shown in the drawing, the other end of the seat belt 4 is drawn into the vehicle compartment from the outlet at the upper part of the center pillar, inserted into the tongue 5 and fixed to the lower part of the center pillar 2 with bolts 6. The tongue 5 can be fastened and disengaged from a buckle 8 fixed on the vehicle seat side with a bolt 7, and the seat belt 4 when not worn is wound and stored on the spool 3 of the retractor 1 at one end side. When worn, the spool 3 is pulled out into the passenger compartment while being rotated, and the tongue 5 is fastened to the buckle 8.

The retractor 1 is provided with a lock device that restrains the withdrawal of the seat belt 4 when the vehicle collides. The configuration of the lock device is well known and will not be described in detail. However, the deceleration of the vehicle, the acceleration of the seat belt 4 and the like are detected, and the withdrawal of the seat belt 4 is restricted by the ratchet mechanism, thereby restraining the occupant. Prevent jumping forward.
A driven gear 9 is connected to the rotation shaft 3 a of the spool 3 of the retractor 1, and the driven gear 9 meshes with a drive gear 10 disposed below the spool 3. The drive gear 10 is connected to the motor 11 via a one-way clutch (not shown), and the one-way clutch transmits a rotational force only in the winding direction of the seat belt 4. In the present embodiment, a motor belt mechanism is configured by the driven gear 9, the drive gear 10, the one-way clutch, and the motor 11.

  Therefore, when the motor 11 rotates in the belt winding direction, the rotational force is transmitted to the spool 3 via the drive gear 10 and the driven gear 9, so that the rotational force of the motor 11 is added to the biasing force of the spiral spring. The seat belt 4 is wound around the spool 3 by force. As will be described later, the motor torque can be switched between two stages of LO and HI (corresponding to belt tensions F2 and F3 described later) by adjusting the energization current. On the other hand, the transmission of the rotational force of the spool 3 accompanying the withdrawal of the seat belt 4 to the motor side is blocked by the one-way clutch, thereby preventing the motor 11 from becoming a resistance of the belt withdrawal.

The spool 3 is provided with a rotation speed sensor 12 (belt drawing detection means) for detecting the rotation speed. For example, the rotational speed sensor 12 is a coil-type sensor in which a detection element such as a coil is disposed opposite to a detection gear connected on the rotation shaft of the spool 3 and a detection pulse is output by a magnetic field change accompanying rotation of the detection gear. Can be configured as
On the other hand, a pre-crash ECU (electronic control unit) 21 (motor rotation control means), an electric control ECU (for example, a meter ECU) 22 for controlling general electric equipment of the vehicle, a brake control, etc. ECUs 23 are connected via a bus 24. These ECUs 21 to 23 include an input / output device (not shown), a storage device (ROM, RAM, BURAM, etc.) used for storing control programs, control maps, and the like. It consists of a processing unit (CPU), a timer counter and the like. The pre-crash ECU 21 controls the belt tension at the time of sudden braking in addition to the belt tension control at normal times (belt retracted state, belt worn state, etc.). When performing device control, it also recognizes whether or not the belt is worn, and the brake control ECU 23 performs vehicle turning control (stability control), traction control, and brake control (brake assist) for preventing a rear-end collision with a preceding vehicle. Etc.

  The pre-crash ECU 21 is connected to the rotational speed sensor 12 of the retractor 1 and the motor 11. The electric control ECU 22 is connected to a buckle switch 25 (belt wear detecting means) provided in the buckle 8, and the brake control ECU 23 is input with vehicle brake operation information. 24 to the pre-crash ECU 21.

  The pre-crash ECU 21 sequentially counts the detection pulses input from the rotational speed sensor 12, and calculates the seat belt pull-out amount L based on the pull-out amount L = 0 when the seat belt 4 is completely wound around the spool 3. Yes. The pre-crash ECU 21 makes a sudden brake determination based on whether or not the brake depression speed is equal to or higher than a predetermined value based on the brake operation information input via the brake control ECU 23.

Next, the belt tension control executed by the pre-crash ECU 21 of the seat belt apparatus configured as described above will be described.
Table 1 is an explanatory diagram showing the belt tension setting status with respect to the usage status of the seat belt 4, and the fifth level from the uppermost level in the table corresponds to belt tension control during normal operation, and the lowermost level is a belt when sudden braking is performed. This corresponds to tension control, and it is assumed that the sudden brake determination is made only at the lowest level. The belt tension control will be described in accordance with the same table. In the following description, the belt tension by the urging force of the spiral spring is F1, the belt tension on the LO side by the motor 11 is F2, and the belt tension on the HI side by the motor 11 is F3. Define.

  First, when the seat belt 4 is retracted into the retractor 1, the tongue 5 of the seat belt 4 is disengaged from the buckle 8, so that the buckle switch 25 is turned off and the seat belt 4 is completely wound around the spool 3. As a result, the withdrawal amount L = 0 is calculated. At this time, the pre-crash ECU 21 stops and holds the motor 11, and as a result, a relatively weak belt tension F1 corresponding to the urging force of the spiral spring acts on the seat belt 4.

  When the occupant gets into the vehicle from the stored state and pulls out the seat belt 4 for wearing the belt, the detection pulse of the rotational speed sensor 12 is counted along with the belt pull-out, and the pull-out amount L gradually increases. Also at this time, the pre-crash ECU 21 keeps the motor 11 stopped and the belt tension remains F1, so that the occupant can easily pull out the seat belt 4.

  While the seat belt 4 is being pulled out, the pre-crash ECU 21 determines whether or not the elapsed time T from the pull-out start time (the time when the pull-out amount L> 0) has reached a predetermined wearing time T0. When the buckle switch 25 is not turned on even after the required wearing time T0 has elapsed as described later, belt winding processing is performed. The required wearing time T0 is set with a sufficient allowance for a general required time from when the occupant starts pulling out the belt until the wearing is completed, and usually the required wearing time T0 elapses. Previously, the tongue 5 of the seat belt 4 was fastened to the buckle 8 by the occupant and the buckle switch 25 was turned on.

As the tongue 5 is fastened to the buckle 8 in this way, the wearing of the seat belt 4 is completed, and the buckle switch 25 is switched on. At this time, the pre-crash ECU 21 continues to stop and hold the motor 11. The belt tension remains F1. Therefore, the occupant can sit on the seat without feeling a sense of pressure due to the restraint of the seat belt 4.
On the other hand, the buckle switch 25 is turned off when the buckle 8 of the seat belt 4 is disengaged in order for the occupant to get out of the vehicle from the wearing state. At this time, the pre-crash ECU 21 operates the motor 11 to adjust the motor torque to the LO side so as to act on the spool 3. As a result, a relatively strong belt tension F1 + F2 acts on the seat belt 4 so that the seat belt 4 is quickly and reliably wound on the spool 3.

As the seat belt 4 is retracted, the pull-out amount L based on the count of detection pulses gradually decreases, and the pre-crash ECU 21 stops the operation of the motor 11 when the pull-out amount L of the seat belt 4 returns to zero. Therefore, the belt tension is again weakened to F1 in the case of only the spiral spring, and the belt is restored to the stored state.
On the other hand, in the middle of pulling out the seat belt 4 (withdrawal amount L> 0), for example, when the occupant goes out of the vehicle to pick up forgotten things, the seat belt 4 is left in the middle of pulling out. At this time, the pre-crash ECU 21 operates the motor 11 with the torque on the LO side because the buckle switch 25 is not turned on even when the required wearing time T0 has elapsed. As a result, the seat belt 4 in the middle of being pulled out is wound up quickly and reliably under the relatively strong belt tension F1 + F2 as in the case of the normal belt winding by the buckle disengagement, and the seat belt 4 in the middle of being pulled out is suspended. Problems such as obstructions are prevented.

The operation stop of the motor 11 is also determined based on the pull-out amount L as in the normal belt winding, and when the pull-out amount L returns to 0, the motor 11 is stopped and returned to the stored state. .
On the other hand, when wearing the belt with the buckle switch 25 turned on and the seat belt 4 being pulled out, when the sudden brake determination is made based on the brake depression speed of a predetermined value or more, the pre-crash ECU 21 operates the motor 11. Adjust the motor torque to the HI side. As a result, a strong belt tension F1 + F3 acts on the seat belt 4 and the restraint of the occupant by the seat belt 4 becomes stronger, and the occupant can be surely protected even in the event of a collision immediately thereafter.

  By the way, as described in “Problems to be Solved by the Invention”, the pull-out process of the seat belt 4 differs depending on the occupant's heel and surrounding conditions, and the belt pull-out operation is performed despite the intention to wear the belt. May be interrupted. In such a case, in this embodiment, since the determination is based on the elapsed time T from the start of belt withdrawal to the completion of wearing, even if the belt withdrawal operation is interrupted somewhat, the time required for belt wearing as a whole is extended so much. The elapsed time T does not reach the wearing time T0. Therefore, there is no possibility that the belt tension is unnecessarily increased when the occupant intends to wear the belt in this way, and the occupant's uncomfortable feeling due to this can be prevented beforehand, thereby improving the commercial value of the seat belt device. be able to.

  In addition, since the motor 11 for generating the belt tension F3 at the time of sudden braking is also used as the belt tension F2 for winding the belt, for example, in Patent Document 1 in which two types of spiral springs are switched by a solenoid. Compared to the seat belt device, one spiral spring and solenoid are omitted, and as a result, the configuration can be simplified and the manufacturing cost can be reduced.

  This is the end of the description of the embodiment, but the aspect of the present invention is not limited to this embodiment. For example, in the above embodiment, the belt withdrawal detection means is configured as the coil-type rotation speed sensor 12 and the withdrawal amount L is detected. However, the configuration of the belt withdrawal detection means can be variously changed as shown in FIGS. It is. In these figures, the motor 11 is omitted, but the spool 3 is rotationally driven by the motor 11 as in the above embodiment.

  For example, as shown in FIG. 3, a thickness sensor 31 that changes the resistance value according to the tilt of the detection lever 31 a is disposed near the spool 3, and the detection lever 31 a of the thickness sensor 31 is wound around the spool 3. The resistance value that changes in accordance with the thickness of the seat belt 4 may be detected as the amount of winding of the seat belt 4 by contacting the surface of the belt 4. Further, since it is not always necessary to detect the drawing amount L and the winding amount, for example, a limit switch may be provided in place of the thickness sensor 31 in FIG.

  As shown in FIG. 4, a pin 42 that restricts the movement of the spool 3 in the circumferential direction is disposed in a spiral guide groove 41 formed on the side surface of the spool 3, and has the same configuration as the thickness sensor 31. The detection lever 43 a of the rotational position sensor 43 may be brought into contact with the pin 42. As the spool 3 rotates, the pin 42 moves in the radial direction indicated by the arrow in the drawing, and the resistance value of the rotational position sensor 43 changes according to the movement of the pin 42. As a result, the amount of rotation of the spool 3 is detected. it can.

  Further, the pulled-out state of the seat belt 4 correlates with the tension related to the seat belt 4, that is, the belt tension, and the belt tension increases when the seat belt 4 is pulled out as compared to when fully retracted. The pulled-out state of the seat belt 4 may be detected. Specifically, as shown in FIG. 5, the seat belt 4 is pressed by a pin 52 biased by a compression spring 51 to bend the pulling path, and the front and rear positions of the pin 52 are detected by a potentiometer 53 or the like. To do. When the belt tension increases as the belt is pulled out, the pin 52 is retracted against the compression spring 51 accordingly. On the other hand, when the seat belt 4 is completely wound up, the compression spring is reduced as the belt tension is lowered. Since the pin 52 is advanced by 51, the belt tension can be detected from the front and rear positions of the pin 52.

Further, instead of the configuration in which the front-rear position of the pin 52 is detected by the potentiometer 53, a strain gauge 61 may be attached to the rotating shaft 3a of the spool 3 as shown in FIG. Since the load applied to the rotating shaft 3a changes according to the belt tension, and the amount of bending of the rotating shaft 3a also changes accordingly, the belt tension can be detected from the amount of bending of the rotating shaft 3a.
Since the belt tension and the current of the motor 11 are correlated, the belt tension may be detected based on the motor current detected by the current sensor 71 (shown by a broken line in FIG. 1).

It is a whole lineblock diagram showing the seat belt device of an embodiment. It is the fragmentary sectional view which looked at the retractor from the vehicle front. It is a fragmentary sectional view which shows the retractor of another example which detects belt winding amount with a thickness sensor. It is a fragmentary sectional view which shows the retractor of another example which detects the rotation position of a spool with a rotation position sensor. It is a fragmentary sectional view which shows the retractor of another example which detects belt tension with a potentiometer. It is a fragmentary sectional view which shows the retractor of another example which detects belt tension with a strain gauge.

Explanation of symbols

1 Spool (Rotating body)
4 Seat belt 9 Driven gear (motor belt mechanism)
10 Drive gear (motor belt mechanism)
11 Motor (motor belt mechanism)
12 Rotational speed sensor (Belt drawer detection means)
21 Pre-crash ECU (motor rotation control means)
25 Buckle switch (belt wearing detection means)

Claims (3)

A rotating body that is fixed so that one end of the seat belt is fixed and rotated so that the seat belt can be wound;
An urging member for urging the rotating body in the winding direction of the seat belt;
A seat belt device having a motor belt mechanism capable of rotating the rotating body in the winding direction by a rotational force of a motor;
Belt pull-out detection means for detecting the state of pulling out the seat belt;
Belt wearing detection means for detecting the wearing state of the seat belt;
Motor rotation control means for controlling the rotational force of the motor belt mechanism acting on the rotating body according to the detection results of the belt pull-out detection means and the belt wear detection means;
The motor rotation control unit is configured to detect a predetermined state in which the seat belt is not worn even when a predetermined time has elapsed after the seat belt is pulled out by the belt withdrawal detection unit and the belt wearing detection unit. A seatbelt device, wherein the motor of the motor belt mechanism is operated to rotate the rotating body in a winding direction.   The motor rotation control means stops the operation of the motor when the belt drawing detection means detects completion of winding of the belt after the motor has been rotated in accordance with the detection of the predetermined state. The seat belt device according to claim 1.   The belt pull-out detection means is any one of a pull-out amount from a state in which the seat belt is stored, a rotation position of the rotating body, a winding amount of the seat belt by the rotating body, or a tension relating to the seat belt. 3. The seat belt device according to claim 1, wherein a state in which the seat belt is pulled out is detected accordingly.

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