JP4174108B2 - Vehicle occupant restraint protection device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vehicle occupant restraint protection device installed in a vehicle such as an automobile, and more particularly to a vehicle occupant restraint protection device using an electric retractor that winds and pulls out a seat belt for protecting the occupant.
[0002]
[Prior art]
BACKGROUND ART A vehicle occupant restraint protection device that includes a retractor that winds and pulls out a seat belt is conventionally known. For example, a vehicle occupant restraint protection system described in Japanese Patent Application Laid-Open No. 9-132113 controls a seat belt retractor in consideration of the situation between the vehicle and the object and / or the situation of the vehicle. In particular, a collision of the own vehicle is predicted by a distance sensor, and the seat belt tension (seat belt tension) is increased when the collision is inevitable.
[0003]
[Problems to be solved by the invention]
However, since the vehicle occupant restraint protection system predicts a collision of the host vehicle using a distance sensor, it can predict with high reliability in a road environment with good visibility, but it can accurately predict on a road with poor visibility. In spite of the collision, there was a possibility that it would not be judged that it would collide.
[0004]
In this case, since the seat belt tension is not increased even in the event of a collision, the seat belt is not taken up at the time of the collision, and the occupant may not be restrained sufficiently safely.
[0005]
The present invention has been made paying attention to the above points, and an object of the present invention is to provide a vehicle occupant restraint protection device that can reliably restrain and protect an occupant.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the vehicle occupant restraint protection device according to claim 1 is a first drive means for rotationally driving a reel shaft for winding up a seat belt by a rotational force of a motor controlled by a PWM signal. And a second driving means for rotationally driving the reel shaft for winding the seat belt by the force of gas generated by the combustion of explosives, a collision prediction means for predicting a vehicle collision, and a vehicle collision detection When a collision of the vehicle is predicted by the collision detection means and the collision prediction means, the first driving means is driven, and then when the collision of the vehicle is detected by the collision detection means, with driving the second drive means, to determine the presence or absence of a collision of the vehicle by the collision detection means even when the collision of the vehicle is not foreseen by the collision prediction means, collision of the vehicle When it is detected, characterized in that it comprises a control means for driving the second drive means.
[0007]
According to the configuration of the present invention, when the collision of the vehicle is predicted by the collision prediction unit, the first drive unit is driven, and then, when the collision of the vehicle is detected by the collision detection unit, the second driving unit is driven. Since the driving means is driven, the slack of the seat belt is removed by the first driving means before the collision of the vehicle, and the tension of the seat belt is increased, and the tension is further increased by the second driving means after the collision. Further, even when the collision prediction means does not predict the collision of the vehicle, the collision detection means determines the presence or absence of the collision of the vehicle, and when the collision of the vehicle is detected, the second drive means is driven. Even if the collision is unavoidable in reality, even if it is predicted by the collision prediction means that the collision is unavoidable, the second drive means is driven immediately after the collision. Therefore, the passenger is surely restrained and protected.
The collision prediction means includes distance measuring means for measuring a distance between the host vehicle and an object ahead of the host vehicle, and the control means is configured to change the first according to a measurement result by the distance measuring means. The rotational driving force of the reel shaft by the driving means is changed. Thereby, the tension of the seat belt can be increased before the collision, and the occupant is appropriately protected at the time of the collision.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0009]
FIG. 1 is a diagram showing a configuration of an electric retractor 100 provided in a vehicle occupant restraint protection device according to an embodiment of the present invention.
[0010]
The electric retractor 100 includes a frame 1. A reel shaft 3 that winds up the seat belt is rotatably installed on the frame 1, and the drawer of the seat belt is locked when a predetermined deceleration acts on the vehicle or when the seat belt is pulled out at a predetermined acceleration. A known seat belt locking mechanism 2 is fixed.
[0011]
Next, the central axis 3 a of the reel shaft 3 is connected to the central axis of the pretensioner mechanism 4 and the central axis of the reel shaft pulley 5, and the pretensioner mechanism 4 is connected to a collision detection unit 8 that detects a vehicle collision. Has been.
[0012]
FIG. 2 is a configuration diagram of the pretensioner mechanism 4. The pretensioner mechanism 4 is, for example, an explosive pretensioner, and is connected to a gas chamber 21 that encloses gas generated from the gas generator 20 and the central shaft 3a of the reel shaft 3, and a predetermined number of external teeth are arranged on the outer periphery. And a rack 22 that seals the gas sealed in the gas chamber 21 at the other end, and is configured to engage with the predetermined number of external teeth. .
[0013]
When a collision of the host vehicle is detected by the collision detection unit 8 and an activation signal is input to the pretensioner mechanism 4, gas is generated from the gas generator 20 and enclosed in the gas chamber 21. Since this gas is sealed by the rack 22, the pressure in the gas chamber 21 increases and the rack 22 is pushed down. When the rack 22 is pushed down, the pinion 23 rotates in conjunction with the movement of the rack 22 and the reel shaft 3 connected to the pinion 23 rotates to the seat belt winding side. As a result, the seat belt is rapidly wound when the vehicle collides. When the pretensioner mechanism 4 does not operate, the reel shaft 3 is not obstructed from rotating.
[0014]
FIG. 3 is a block diagram showing the configuration of the collision detection unit 8.
[0015]
The collision detection unit 8 includes an acceleration sensor 31 that detects the acceleration of the vehicle. The acceleration signal obtained from the acceleration sensor 31 is amplified to a predetermined level by the buffer amplifier 32. In the amplified acceleration signal, unnecessary frequency components are attenuated by the high-pass filter 33, thereby reducing the possibility of erroneous determination due to the rise of the acceleration signal seen in the latter half of the low-speed collision. The high pass filter 33 is a so-called CR type high pass filter using a resistor and a capacitor. The output signal of the high-pass filter 33 is firstly integrated by the low-pass filter 34 to be converted into a “velocity” dimension, and then further integrated by the first-order integration by the low-pass filter 35 to be a “displacement” dimension. The low-pass filters 34 and 35 are configured by using resistors and capacitors, and perform an estimation calculation of the occupant change amount. The obtained displacement equivalent amount is compared with a predetermined threshold value Vref in the comparator 36. The comparison result is output as a collision determination output Vout, and this collision determination output Vout is used as an activation signal for the pretensioner mechanism 4.
[0016]
Returning to FIG. 1, the reel shaft pulley 5 is connected to a DC motor pulley 6 through a power transmission belt 7.
[0017]
A predetermined number of external teeth are formed on the outer periphery of each of the reel shaft pulley 5 and the DC motor pulley 6, and a predetermined number of internal teeth are also formed on the inner periphery of the power transmission belt 7. 5 and the external teeth of the DC motor pulley 6 and the internal teeth of the power transmission belt 7 mesh with each other without excess or deficiency.
[0018]
The central axis of the DC motor pulley 6 is connected to the DC motor 10. Accordingly, the rotation of the DC motor 10 is transmitted to the reel shaft 3 via the DC motor pulley 6.
[0019]
The DC motor 10 is fixed to the frame 1 at at least two points, and is connected to an MPU (Micro Processing Unit) 14 via a DC motor driving unit 11. The DC motor drive unit 11 controls the rotation of the DC motor 10 based on a PWM (pulse width modulation) signal from the MPU 14.
[0020]
FIG. 4 is a circuit diagram of the DC motor driving unit 11. Terminals P1 and P2 in FIG. 4 are input terminals for PWM (pulse width modulation) signals output from the MPU 14, and a PWM signal of 20 kHz, for example, is input to the terminals P1 and P2. The terminals P3 and P4 are current detection output terminals, the terminals P5 and P6 are voltage detection output terminals, and the terminals P1 to P6 are connected to the MPU 14, respectively. The voltage Vb in FIG. 4 is supplied to the DC motor 10, and the plurality of transistors, FETs, and the like in FIG. 4 are for driving the rotation of the DC motor 10 forward or reverse by a PWM signal from the MPU 14. is there.
[0021]
A circuit C1 in FIG. 4 is a current detection circuit that detects a current i that flows through the DC motor 10 from a current that flows through the resistor r1, and is an interface circuit (hereinafter referred to as IF) for removing current fluctuation due to the influence of the PWM signal. 1 and IF2. The MPU 14 receives voltage signals from the IF1 and IF2, and detects the current i flowing through the DC motor 10 based on the voltage signals.
[0022]
The circuit C2 is a voltage measurement circuit that measures the voltage across the terminal applied to the DC motor 10, and includes IF3 and IF4 in order to remove fluctuations in the voltage across the terminals due to the influence of the PWM signal. MPU14 receives a voltage signal from IF3 and IF4, respectively, and measures the voltage between terminals concerning DC motor 10 based on this voltage signal.
[0023]
IF1 to IF4 have a low-pass filter configuration including, for example, a resistor r2, a resistor r3 having a resistance value smaller than the resistor r2, and a capacitor c3, and a cutoff frequency is set to 20 Hz, for example. As a result, the influence of the PWM signal output to the MPU 14 by the current detection circuit C1 and the voltage measurement circuit C2 is reduced to −60 dB, and the current or voltage measurement circuit C2 that is originally detected by the current detection circuit C1 is to be measured. Almost no influence on the voltage between terminals.
[0024]
Returning to FIG. 1, the MPU 14 includes a timer 15 for measuring time, and detects whether or not the seat belt tongue is attached to the buckle and detects whether or not the seat belt tongue is released from the buckle. The presence / absence detection unit 13 and a collision prediction unit 16 for predicting a collision of the host vehicle are connected to each other.
[0025]
The MPU 14 determines whether or not the seat belt has been pulled out based on the polarity of the voltage between the terminals of the DC motor 10, and determines whether or not the seat belt has been retracted from the current i flowing through the DC motor 10.
[0026]
When the MPU 14 detects the seat belt being pulled out by the occupant when the seat belt is worn, the MPU 14 attaches the seat belt tongue to the buckle and the seat belt wearing assist control for controlling the DC motor 10 so that the seat belt is easily pulled out. After the seat belt is retracted, the seat belt is fitted to the occupant's body, and after the seat belt has reached its limit, the DC motor 10 is controlled so as to give the passenger a predetermined slack. And a movement control for controlling the DC motor 10 so that the seat belt can be easily pulled out when the occupant tries to move out after the seat belt is mounted, and when the seat belt is pulled out but is not mounted. Seatbelt when belt tongue is released from buckle It executes a storage control for controlling the DC motor 10 so as to store.
[0027]
Next, the buckle connection presence / absence detecting unit 13 detects whether or not the seat belt tongue is attached to the buckle, or detects whether or not the seat belt tongue is released from the buckle, and sends a control signal corresponding thereto to the MPU 14. Output.
[0028]
The collision prediction unit 16 controls the distance sensor 17 that measures the distance between the host vehicle and an object ahead of the host vehicle, the steering angle sensor 18 that detects the steering angle of the steering, and the distance sensor 17 and the steering angle sensor 18. MPU 19 is provided.
[0029]
The distance sensor 17 outputs a control signal indicating the measurement result of the distance between the host vehicle and an object ahead of the host vehicle to the MPU 19. The MPU 19 calculates a safe inter-vehicle distance ds obtained from the following equation (1), and outputs a control signal indicating a collision danger warning to the MPU 14 when the safe inter-vehicle distance ds is larger than the value output from the distance sensor 17. . At this time, the MPU 14 performs a collision danger alarm control that alternately repeats the withdrawal and winding of the seat belt. Thereby, the passenger | crew can recognize being in the situation of a collision danger. Further, the MPU 19 calculates a collision unavoidable distance dd obtained from the following equation (2), and outputs a control signal indicating the collision unavoidable to the MPU 14 when the collision unavoidable distance dd is larger than the value output from the distance sensor 17. To do. At this time, the MPU 14 performs a collision unavoidable control in which the seat belt is retracted by changing the seat belt retracting force in accordance with the value output from the distance sensor 17. Thereby, a passenger | crew is appropriately protected at the time of a collision.
[0030]
ds = Vr × (td + β) (1)
dd = Vr × td (2)
ds: Safety inter-vehicle distance (unit: m)
dd: Collision inevitable distance (unit: m)
Vr: Relative speed (unit: m / s)
td: Driver's response delay (example 0.5-2 seconds)
β: Value determined from vehicle braking characteristics (eg 0.5 to 2 seconds)
Further, the steering angle sensor 18 outputs a control signal corresponding to the steering angle of the steering to the MPU 19, and the MPU 19 has a maximum value of the change amount of the steering angle within a specified time (for example, 2 seconds) as a specified value (for example, 8 degrees). If it is within the range, it is determined that there is a sign of dozing, and a control signal indicating a dozing alarm is output to the MPU 14. At this time, the MPU 14 performs doze driving prevention control that alternately repeats the withdrawal and winding of the seat belt. Thereby, the passenger | crew can recognize that it is in the condition of a dozing driving.
[0031]
FIG. 5 is a flowchart showing the control performed by the electric retractor 100 before and after the collision of the vehicle.
[0032]
First, it is determined whether or not the MPU 19 of the collision prediction unit 11 is unavoidable before the collision of the vehicle (step S51). If the collision is unavoidable, the process proceeds to step S53, which will be described later. The MPU 19 sends a control signal indicating that a collision is unavoidable to the MPU 14, and the MPU 14 increases the driving force of the DC motor 10 and winds up the seat belt (step S52). This increases the tension of the seat belt. Here, the driving force of the DC motor 10 is increased by changing the duty ratio of the PWM signal input to the DC motor driving unit 11.
[0033]
Next, it is determined whether or not the collision detection unit 8 has detected a vehicle collision (step S53). If no vehicle collision is detected, the process returns to step S51 while a vehicle collision is detected. In this case, an activation signal is input from the collision detection unit 8 to the pretensioner mechanism 4, and the pretensioner mechanism 4 rapidly winds up the seat belt by the force of the gas generated from the gas generator 20 (step S54). finish. The tension of the seat belt also increases by winding the seat belt in step S54.
[0034]
As described above, according to the present embodiment, when it is determined that a collision is inevitable before a vehicle collision, the MPU 14 increases the driving force of the DC motor 10 and winds up the seat belt (step S52). ) Increase the tension of the seat belt. Furthermore, when a vehicle collision is detected, the pretensioner mechanism 4 rapidly winds up the seat belt by the force of gas generated from the gas generator 20 (step S54), and the tension of the seat belt is increased. Since the slack of the seat belt is removed before the tension of the seat belt is increased and the tension is further increased after the collision, the occupant is reliably restrained and protected.
[0035]
Further, for example, when the collision prediction unit 11 predicts that the collision is unavoidable even though the collision is actually unavoidable, the tension of the seat belt is increased by the winding of the seat belt by the pretensioner mechanism 4 immediately after the collision. Since the size is increased, the occupant can be reliably restrained and protected.
[0036]
Further, for example, even when the seat belt is not taken up by the pretensioner mechanism 4 at a normal timing due to a collision portion of the own vehicle, the MPU 14 increases the driving force of the DC motor 10 in advance before the vehicle collision. Since the seat belt is wound (step S52) and the tension of the seat belt is increased, the occupant can be reliably restrained and protected. Therefore, the occupant can be restrained and protected more appropriately than the case where only the collision is detected and the occupant is restrained and protected.
[0037]
In the present embodiment, the driving force of the DC motor 10 and the winding of the seat belt by the pretensioner mechanism 4 are performed, but the pretensioner mechanism 4 is replaced with a DC motor separately, and the DC motor 10 is replaced before the collision. Even if it is configured to drive and drive the DC motor replaced immediately after the collision, the same effect as the present invention can be obtained.
[0038]
【The invention's effect】
As described above in detail, according to the vehicle occupant restraint protection apparatus of claim 1, when a collision of the vehicle is predicted by the collision prediction means, the first drive means is driven and the vehicle is detected by the collision detection means. When the collision is detected, the second driving means is driven, so that the slack of the seat belt is removed by the first driving means before the collision of the vehicle, the tension of the seat belt is increased, and the second driving means is further increased after the collision. This increases the tension. Therefore, the passenger is surely restrained and protected.
[0039]
For example, even if it is predicted that the collision is inevitable by the collision predicting means even though it is actually inevitable, the second driving means is driven immediately after the collision, so that the occupant can be reliably restrained and protected. it can.
[0040]
Further, for example, even if the second drive means is not driven immediately after the collision at a normal timing, the first drive means is driven in advance before the collision, so that the occupant can be reliably restrained and protected. Therefore, the occupant can be restrained and protected more appropriately than the case where only the collision is detected and the occupant is restrained and protected.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of an electric retractor 100 included in a vehicle occupant restraint protection device according to an embodiment of the present invention.
FIG. 2 is a configuration diagram of a pretensioner mechanism 4;
FIG. 3 is a block diagram illustrating a configuration of a collision detection unit 8;
FIG. 4 is a circuit diagram of a DC motor driving unit 11;
FIG. 5 is a flowchart showing control performed by the electric retractor 100 before and after a vehicle collision.
[Explanation of symbols]
1 Frame 2 Seat belt lock mechanism 3 Reel shaft 4 Pretensioner mechanism (second drive means)
5 Reel shaft pulley 6 DC motor pulley 7 Power transmission belt 8 Collision detector (collision detection means)
10 DC motor (first drive means)
11 DC motor drive unit 13 Collision prediction unit (collision prediction means)
14 MPU
100 electric retractor

Claims (2)

First driving means for rotationally driving a reel shaft for winding the seat belt with a rotational force of a motor controlled by a PWM signal;
Second driving means for rotationally driving a reel shaft for winding up the seat belt with the force of gas generated by combustion of explosive;
A collision prediction means for predicting a vehicle collision;
A collision detection means for detecting a vehicle collision;
When a collision of the vehicle is predicted by the collision prediction means, the first drive means is driven. After that, when a collision of the vehicle is detected by the collision detection means, the second drive means is driven. In addition, even when a collision of the vehicle is not predicted by the collision prediction unit, the collision detection unit determines whether or not the vehicle has collided. If a vehicle collision is detected, the second drive unit is A vehicle occupant restraint protection device, comprising: a control means for driving . The collision prediction means includes distance measuring means for measuring a distance between the host vehicle and an object ahead of the host vehicle,
2. The vehicle occupant restraint protection device according to claim 1, wherein the control unit changes a rotational driving force of the reel shaft by the first driving unit in accordance with a measurement result by the distance measuring unit.

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