JPH11192926A - Vehicle occupant restraint system - Google Patents

Abstract

(57) [Problem] To provide a vehicle occupant restraint protection device capable of preventing a failure of a driving means. SOLUTION: When an MPU 14 executes a state control program, a current i flowing through a DC motor 10 is larger than 1.4 A and this state exceeds 60 seconds (step S4).
2 Yes, Step S45 Yes), tension α is 12
mN and this state exceeds 60 seconds (Yes in step S52, Yes in step S55)
s), when the rotation torque β is larger than 30 mN · cm and this state exceeds 60 seconds (Ye in step S62)
s, Yes in step S65), or the temperature γ is 100 ° C.
If it is larger and this state exceeds 60 seconds (Yes in step S72, Yes in step S75),
When it is determined that the DC motor 10 is in an abnormal state,
5, the supply of the power supply voltage from the battery voltage Vb to the DC motor 10 is stopped (steps S46 and S5).
6, Step S66, Step S76).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle occupant restraint system mounted on a vehicle such as an automobile, and more particularly to a vehicle using an electric retractor for winding and pulling out a seat belt for protecting the occupant. The present invention relates to an occupant restraint device.

[0002]

2. Description of the Related Art An occupant restraint protection device for a vehicle having an electric retractor for pulling out or winding up a seat belt is conventionally known, and this electric retractor is driven by, for example, a motor for driving the electric retractor. The driving means is provided.

[0003] When the motor is driven continuously, the temperature of the motor exceeds the endurance temperature of the motor, and the motor sometimes breaks down.

[0004]

However, the above-mentioned conventional vehicle occupant restraint system does not have a function of preventing the failure before the failure occurs.

[0005] The present invention has been made in view of the above points, and has as its object to provide a vehicle occupant restraint protection device which can prevent a failure of a driving means.

[0006]

According to a first aspect of the present invention, there is provided an occupant restraint system for a vehicle, comprising: an electric retractor for retracting and retracting a seat belt; and a driving unit for driving the electric retractor. Detecting means for detecting an abnormal state of the driving means, and a power supply for reducing a power supply voltage supplied to the driving means when an abnormal state of the driving means is detected. Voltage reducing means.

According to the structure of the present invention, the power supply voltage supplied to the driving means is reduced when an abnormal state of the driving means is detected, so that an excessive power supply voltage is not supplied to the driving means. Can be prevented.

The vehicle occupant restraint protection device further includes a current measuring means for measuring a current flowing through the driving means, and a time measuring means for measuring time, and the current measuring means for a predetermined time measured by the time measuring means. In the case where a current exceeding a predetermined value is measured, the detecting means may detect an abnormal state of the driving means.

According to the above arrangement, when the current measuring means measures a current exceeding a predetermined value for a predetermined time measured by the time measuring means, the power supply voltage supplied to the driving means is reduced. The power supply voltage does not need to be supplied excessively, and the failure of the driving means can be more accurately prevented.

[0010] The occupant restraint protection device for a vehicle further includes tension measuring means for measuring the tension of the seat belt, and time measuring means for measuring time, and the predetermined time measured by the time measuring means is used by the tension measuring means. The detecting means may detect an abnormal state of the driving means when a tension exceeding a predetermined value is measured.

According to the above construction, the power supply voltage supplied to the driving means is reduced when the tension measuring means measures a tension exceeding a predetermined value for a predetermined time measured by the timing means. The power supply voltage does not need to be supplied excessively, and the failure of the driving means can be more accurately prevented.

[0012] The occupant restraint protection device for a vehicle further includes a torque measuring means for measuring a rotational torque of the electric retractor, and a time measuring means for measuring time, and the torque measuring means for a predetermined time measured by the time measuring means. When a rotational torque exceeding a predetermined value is measured by the control unit, the detecting unit may detect an abnormal state of the driving unit.

According to the above configuration, the power supply voltage supplied to the driving means is reduced when the torque measuring means measures a rotation torque exceeding a predetermined value for a predetermined time measured by the time measuring means. An excessive power supply voltage is not supplied to the means, and the failure of the driving means can be more accurately prevented.

The vehicle occupant restraint protection device further includes a temperature measuring means for measuring a temperature near the driving means or the temperature of the driving means itself, and a time measuring means for measuring time, and a predetermined time measured by the time measuring means. The detecting means may detect an abnormal state of the driving means when a temperature exceeding a predetermined value is measured by the temperature measuring means for a time.

According to the above arrangement, the power supply voltage supplied to the driving means is reduced when the temperature exceeding the predetermined value is measured by the temperature measuring means for a predetermined time measured by the time measuring means. The power supply voltage does not need to be supplied excessively, and the failure of the driving means can be more accurately prevented.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

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.

The electric retractor 100 has a frame 1. A reel shaft 3 that winds up the seat belt 8 is rotatably mounted on the frame 1, and the seat belt 8 is pulled out when a predetermined deceleration is applied to the vehicle or when the seat belt 8 is pulled out at a predetermined acceleration. Is fixed. Further, the electric retractor 100 includes a tension sensor 9 for measuring the tension α of the seat belt 8.

The center shaft 3a of the reel shaft 3 is provided with a torque sensor 4 for measuring the rotation torque β of the reel shaft 3, and is connected to the center shaft of a reel shaft pulley 5. The reel shaft pulley 5 is connected to a DC motor pulley 6 via a power transmission belt 7.
A biasing force applying means such as a spiral spring is formed inside the reel shaft pulley 5, and the biasing force always acts in a direction in which the seat belt 8 is wound.

A predetermined number of external teeth are formed on the outer circumference of the pulley 5 for the reel shaft and the pulley 6 for the DC motor, respectively, and a predetermined number of internal teeth are also formed on the inner circumference of the power transmission belt 7. The external teeth of the shaft pulley 5 and the DC motor pulley 6 mesh with the internal teeth of the power transmission belt 7 without excess or deficiency.

The center axis of the DC motor pulley 6 is connected to the DC motor 10. Accordingly, the rotation of the DC motor 10 is controlled via the DC motor pulley 6 by the reel shaft 3.
Is transmitted to

The DC motor 10 is fixed to the frame 1 at at least two points.
1 is connected to an MPU (Micro Processing Unit) 14.

The MPU 14 includes a torque sensor 4, a tension sensor 9, a buckle connection presence / absence detector 16 for detecting whether or not the tongue of the seat belt 8 is attached to the buckle, and a temperature near the DC motor 10 or the temperature of the DC motor 10 itself. Each is connected to a temperature sensor 12 for measuring γ.

Further, the MPU 14 is connected to an alarm unit 15 which issues an alarm when the MPU 14 detects an abnormal state of the DC motor 10 described later.

The buckle connection presence / absence detecting section 16 detects whether or not the tongue of the seat belt 8 is attached to the buckle.
The corresponding electrical signal is output to the MPU 14. The DC motor drive unit 11 controls the rotation of the DC motor 10 based on an electric signal from the MPU 14. The tension sensor 9 measures the tension α of the seat belt 8 and outputs an electric signal corresponding to the measurement result to the MPU 14. The torque sensor 4 measures the rotation torque β of the reel shaft 3 and outputs an electric signal corresponding to the measurement result to the MPU 14. Temperature sensor 12 measures temperature γ of DC motor 10 or DC motor 10 itself, and outputs an electric signal corresponding to the measurement result to MPU 14.

The MPU 14 has a timer (not shown) for measuring an elapsed time t from the start of a state control program described later.

FIG. 2 is a circuit diagram of the DC motor drive unit 11. The terminals P1 and P2 of the MPU 14 in FIG. 2 are output terminals for electric signals, and the terminals P3 and P4 are input terminals for electric signals. The current detection circuit C1 in FIG. 2 is configured to calculate the current i flowing through the DC motor 10 from the current flowing through the resistor r1.
Is detected. The battery voltage Vb supplies a power supply voltage to the DC motor 10 via a switch 25, for example, a relay or a transistor. Also, the transistor 2 in FIG.
0, 23, 24 and FETs 21, 22 are for driving the DC motor 10 to rotate by an electric signal from the MPU 14.

The battery voltage Vb is connected to the terminal P3 of the MPU 14 via a resistor included in the current detection circuit C1, and further connected to the source of the FET 21 via a resistor r1 included in the current detection circuit C1. The resistor r1 is connected to a terminal P4 of the MPU 14 via a resistor included in the current detection circuit C1. The gate of the FET 21 is connected to the collector of the transistor 20 via a resistor, the emitter of the transistor 20 is grounded, and the base of the transistor 20 is connected to the terminal P1 of the MPU 14 via a resistor.

The drain of the FET 21 is connected to the DC motor 10, and the DC motor 10 is connected to one end of the resistor and the drain of the FET 22. The other end of the resistor connected to the DC motor 10 and the source of the FET 22 are grounded.

The gate of the FET 22 is connected to the collector of the transistor 23, and a power supply voltage of 5 V is applied through a resistor. The base of the transistor 23 is connected to the collector of the transistor 24, and the emitters of the transistor 23 and the transistor 24 are grounded. The base of the transistor 24 is connected to the terminal P2 of the MPU 14 via a resistor.

The MPU 14 controls so as not to output a high-level signal from the terminal P1 and the terminal P2 at the same time.

FIG. 3 is a main flowchart of a state control program executed by the MPU 14, and this state control program is executed at predetermined time intervals.

First, state control is performed based on the measurement result of the current i flowing through the DC motor 10 (step S31).
Details of this state control will be described later with reference to FIG. When the state control in step S31 starts, the M
The timer of the PU 14 starts measuring the elapsed time t from the start of the state control program in step S31.

Next, the seat belt 8 is detected by the tension sensor 9.
The state control is performed based on the measurement result of the tension α of (step S32). Details of this state control will be described later with reference to FIG. When the state control in step S32 starts, the timer provided in the MPU 14 starts in step S3.
Elapsed time t from the start of the state control program 2
Start measuring.

Next, state control is performed based on the measurement result of the rotation torque β of the reel shaft 3 by the torque sensor 4 (step S33). Details of this state control will be described later with reference to FIG. When the state control in step S33 starts, the timer provided in the MPU 14 starts measuring the elapsed time t from when the state control program in step S33 is started.

Finally, state control is performed based on the result of measurement of the temperature γ of the DC motor 10 in the vicinity of the DC motor 10 by the temperature sensor 12 (step S34), and the process returns to step S31. For details of this state control, see FIG.
Will be described later. When the state control in step S34 starts, the timer of the MPU 14 starts measuring the elapsed time t from when the state control program in step S34 is started.

FIG. 4 is a flowchart showing details of the state control program in step S31.

First, the current i flowing through the DC motor 10 is detected by the current detection circuit C1 (step S41), and in step S42, it is determined whether the current i is greater than 1.4A.

If the current i is not more than 1.4 A in step S42, it is determined that the DC motor 10 is in a normal state, and the elapsed time t from the start of the state control program is reset (t ← 0) (step S44), the state control program ends. On the other hand, when the current i is 1.4 A
If it is larger, the elapsed time t from the start of this state control program is incremented by one (t ← t +
1) (Step S43).

Next, in step S45, it is determined whether or not the elapsed time t from the start of this state control program has exceeded 60 seconds.

In step S45, if the elapsed time t from the start of the present state control program is within 60 seconds, it is determined that the DC motor 10 is in a normal state, and the present state control program is terminated. On the other hand, if the elapsed time t from the start of the state control program exceeds 60 seconds, it is determined that the DC motor 10 is in an abnormal state, and the power from the battery voltage Vb to the DC motor 10 is The supply of the voltage is stopped (step S46), and the state control program ends.

According to the state control program in step S31, when the current i flowing through the DC motor 10 is larger than 1.4 A and this state exceeds 60 seconds (Yes in step S42, Yes in step S45) ), It is determined that the DC motor 10 is in an abnormal state,
As a result, the supply of the power supply voltage from the battery voltage Vb to the DC motor 10 is stopped (step S46), so that the failure of the DC motor 10 can be prevented.

FIG. 5 is a flowchart showing details of the state control program in step S32.

First, the seat belt 8 is detected by the tension sensor 9.
Is measured (step S51), and step S52 is performed.
, It is determined whether or not the tension α is greater than 12 mN.

If the tension α is equal to or less than 12 mN in step S52, it is determined that the DC motor 10 is in a normal state, and the elapsed time t from the start of this state control program is reset (t ← 0). ) (Step S54), the state control program ends. On the other hand, the tension α is 12 mN
If it is larger, the elapsed time t from the start of this state control program is incremented by one (t ← t +
1) (Step S53).

Next, in step S55, it is determined whether or not the elapsed time t from the start of the state control program has exceeded 60 seconds.

In step S55, if the elapsed time t from the start of the present state control program is within 60 seconds, it is determined that the DC motor 10 is in a normal state, and the present state control program is terminated. On the other hand, if the elapsed time t from the start of the state control program exceeds 60 seconds, it is determined that the DC motor 10 is in an abnormal state, and the power from the battery voltage Vb to the DC motor 10 is The supply of the voltage is stopped (step S56), and the state control program ends.

According to the state control program in step S32, when the tension α is larger than 12 mN and this state exceeds 60 seconds (Yes in step S52,
(Yes in step S55), it is determined that the DC motor 10 is in an abnormal state, and the switch 25 switches the battery voltage Vb
Then, the supply of the power supply voltage to the DC motor 10 is stopped (step S56), so that the failure of the DC motor 10 can be prevented.

FIG. 6 is a flowchart showing details of the state control program in step S33.

First, the rotation torque β of the reel shaft 3 is measured by the torque sensor 4 (step S61), and in step S62, it is determined whether or not the rotation torque β is greater than 30 mN · cm.

In step S62, the rotational torque β is 30 m
If it is equal to or less than N · cm, it is determined that the DC motor 10 is in a normal state, and the elapsed time t from the start of this state control program is reset (t ← 0) (step S6).
4), end the state control program. On the other hand, if the rotation torque β is larger than 30 mN · cm, the elapsed time t from the start of this state control program is incremented by 1 (t ← t + 1) (step S63).

Next, in step S65, it is determined whether or not the elapsed time t from the start of this state control program has exceeded 60 seconds.

In step S65, if the elapsed time t from the start of the present state control program is within 60 seconds, it is determined that the DC motor 10 is in a normal state, and the present state control program is terminated. On the other hand, if the elapsed time t from the start of the state control program exceeds 60 seconds, it is determined that the DC motor 10 is in an abnormal state, and the power from the battery voltage Vb to the DC motor 10 is The supply of the voltage is stopped (step S66), and the state control program ends.

According to the state control program of step S33, the rotational torque β is larger than 30 mN · cm,
If this state exceeds 60 seconds (step S6)
2; Yes in step S65); DC motor 1
It is determined that 0 is an abnormal state, and the supply of the power supply voltage from the battery voltage Vb to the DC motor 10 is stopped by the switch 25 (step S66), so that the failure of the DC motor 10 can be prevented.

FIG. 7 is a flowchart showing details of the state control program in step S34.

First, the DC motor 1 is detected by the temperature sensor 12.
The temperature γ near 0 or the DC motor 10 itself is measured (step S71).
It is determined whether the temperature is higher than 00 ° C.

If the temperature γ is equal to or lower than 100 ° C. in step S72, it is determined that the DC motor 10 is in a normal state, and the elapsed time t from the start of the state control program is reset (t ← t). 0) (step S74), the state control program ends. On the other hand, when the temperature γ is 100 ° C.
If it is larger, the elapsed time t from the start of this state control program is incremented by one (t ← t +
1) (Step S73).

Next, in step S75, it is determined whether or not the elapsed time t from the start of the state control program has exceeded 60 seconds.

If it is determined in step S75 that the elapsed time t from the start of the present state control program is within 60 seconds, it is determined that the DC motor 10 is in a normal state, and the present state control program is terminated. On the other hand, if the elapsed time t from the start of the state control program exceeds 60 seconds, it is determined that the DC motor 10 is in an abnormal state, and the power from the battery voltage Vb to the DC motor 10 is The supply of the voltage is stopped (step S76), and the state control program ends.

According to the state control program in step S34, when the temperature γ is higher than 100 ° C. and this state exceeds 60 seconds (Yes in step S72,
(Yes in step S75), it is determined that the DC motor 10 is in an abnormal state, and the battery voltage Vb is
Since the supply of the power supply voltage to the DC motor 10 is stopped (step S76), the failure of the DC motor 10 can be prevented.

As described above, according to the present embodiment,
When the MPU 14 executes the state control program and the current i flowing through the DC motor 10 is greater than 1.4 A and this state exceeds 60 seconds (Yes in step S42, Yes in step S45), the tension α is less than 12 mN. If it is large and this state exceeds 60 seconds (step S5
2; Yes in step S55);
Is greater than 30 mN · cm and this state exceeds 60 seconds (Yes in step S62, step S65
Yes) or when the temperature γ is higher than 100 ° C. and this state exceeds 60 seconds (Yes in step S72)
s, Yes in step S75), it is determined that the DC motor 10 is in an abnormal state, and the supply of the power supply voltage from the battery voltage Vb to the DC motor 10 is stopped by the switch 25 (steps S46, S56, and S6).
6, step S76), the failure of DC motor 10 can be prevented.

The above steps S46 and S5
6. In steps S66 and S76, it is determined that the DC motor 10 is in an abnormal state, and the supply of the power supply voltage from the battery voltage Vb to the DC motor 10 is stopped by the switch 25. The power supply voltage supplied to the DC motor 10 from Vb may be reduced.

The above steps S46 and S5
6. In steps S66 and S76, it is determined that the DC motor 10 is in an abnormal state, and the supply of the power supply voltage from the battery voltage Vb to the DC motor 10 is stopped by the switch 25. The warning may be issued to inform the occupant of the abnormal state of the DC motor 10.

The MPU 14 may output a pulse signal from the terminal P1 in FIG. 2 so that the pulse width of the pulse signal can be controlled, that is, the duty ratio can be controlled. In this case, when the DC motor 10 is in an abnormal state, the duty ratio of the pulse signal is reduced. This produces the same effect as lowering the power supply voltage supplied to the DC motor 10.

Further, MPU 14 outputs a high-level signal from terminal P2 in FIG. 2 when DC motor 10 is in a normal state, and outputs a low-level signal from terminal P2 in FIG. 2 when DC motor 10 is in an abnormal state. May be output. As a result, the current flowing through the DC motor 10 is reduced, and the same effect as when the power supply voltage supplied to the DC motor 10 is reduced is obtained.

The values of the current i, the tension α, the rotation torque β, and the temperature γ are merely examples, and the present invention is not limited to these values.

[0067]

As described above in detail, according to the vehicle occupant protection device of the first aspect, the power supply voltage supplied to the driving means is reduced when an abnormal state of the driving means is detected. It is not necessary to supply an excessive power supply voltage to the means, and the failure of the driving means can be prevented.

[Brief description of the drawings]

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.

FIG. 2 is a circuit diagram of a DC motor driving unit 11;

FIG. 3 is a main flowchart of a state control program executed by an MPU 14;

FIG. 4 is a flowchart showing details of a state control program in step S31.

FIG. 5 is a flowchart showing details of a state control program in step S32.

FIG. 6 is a flowchart showing details of a state control program in step S33.

FIG. 7 is a flowchart showing details of a state control program in step S34.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Frame 2 Seat belt lock mechanism 3 Reel shaft 4 Torque sensor 5 Reel shaft pulley 6 DC motor pulley 7 Power transmission belt 8 Seat belt 9 Tension sensor 10 DC motor (drive means) 11 DC motor drive unit 12 Temperature sensor 14 MPU (Detection means, power supply voltage lowering means) 25 Switch (power supply voltage lowering means) 100 Electric retractor

Claims (1)

[Claims] 1. An occupant restraint system for a vehicle, comprising: an electric retractor that winds and pulls out a seat belt; and a driving unit that drives the electric retractor. A detecting unit that detects an abnormal state of the driving unit. And a power supply voltage lowering means for lowering a power supply voltage supplied to the driving means when an abnormal state of the driving means is detected.