JP2003160024A - Seat belt device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a seat belt device enabling a passenger to check a failure occurring in a pretensioner motor and the like. <P>SOLUTION: This seat belt device 1 having a pretensioner mechanism winding up a seat belt comprises a motor 2 for winding up the seat belt of a seat belt wind-up device 10, a motor driving means 4 driving the motor 2 by receiving electric power from a power source 15, a driving force transmitting means 3 switching a case connecting driving force transmitted from the motor 2 to the seat belt wind-up device 19 side and a case intercepting the driving force, and failure determining means 5, 6 determining the presence or absence of a failure on the basis of a current waveform generated when the motor driving means 4 drives the motor 2, while the driving force from the motor 2 to the seat belt wind-up device 10 is intercepted. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle seat belt device. In particular, the present invention relates to a seatbelt device with a pretensioner function configured to drive an internal electric motor to apply an appropriate tightening force to a seatbelt to protect an occupant when a vehicle collision is expected.

[0002]

2. Description of the Related Art Many motors are used in vehicles. For example, a motor used in a power steering device or the like can recognize that a failure has occurred when an occupant operates the vehicle. Therefore, it has been conventionally considered that it is not necessary to incorporate a system for detecting a failure of a motor used in a vehicle.

However, in recent years, in the case of an emergency such as a vehicle collision, from the viewpoint of more reliably protecting the occupant, a seat belt is retracted by a built-in motor when a collision is expected. Seat belt devices with a tensioner mechanism have been provided.

[0004]

The pretensioner function of the seat belt device is not normally used, but is set to operate in an emergency when it is determined that there is a possibility of collision by a millimeter wave radar or the like. Has become. Of course, the pretensioner mechanism of the seat belt device is designed so that its function can be sufficiently exerted.

However, there is dust inside the vehicle, and there is an environment where a temperature difference or the like occurs. Therefore, over a long period of time, dust and water adhere to the periphery of the motor rotor, the drive circuit for the motor, etc., and the pretensioner mechanism does not operate as expected due to the adhered dust and rust. Is assumed.

However, since the pretensioner mechanism is used only in an emergency as described above, the motor for the pretensioner and the drive circuit for driving the pretensioner as described above are in a defective state or a failure state (hereinafter, simply referred to as a failure). It is rare for passengers to notice this. That is, even if the pretensioner motor or the like is out of order during normal vehicle operation, the occupant cannot generally recognize this.

Therefore, it is an object of the present invention to provide a seat belt device which allows an occupant to confirm a failure of a motor or the like for a pretensioner.

[0008]

According to a first aspect of the present invention, there is provided a seatbelt device having a pretensioner mechanism for retracting a seatbelt in an emergency, wherein the seatbelt of the seatbelt retractor is wound. The motor for taking up, the motor drive means for driving the motor by receiving the power supply from the power source, the case of connecting the drive force transmitted from the motor to the seat belt retractor side, and the case of disconnecting And a current generated when the motor drive means drives the motor in a state in which the drive force transmission means for switching the motor and the drive force transmission means cut off the drive force from the motor to the seat belt retractor. This is achieved by a seat belt device including a failure determination unit that determines the presence or absence of a failure based on a waveform.

According to the first aspect of the invention, the motor and the motor are driven since the motor is provided with the failure judging means for judging the presence / absence of a failure on the basis of the current waveform obtained by forming the state of idling the motor. It is possible to know that a failure has occurred in the drive circuit or the like. Therefore, it is possible to provide the seat belt device including the pretensioner mechanism that always functions effectively.

Further, as described in claim 2, in the seat belt device according to claim 1, the failure determination means determines a failure when the current waveform does not occur or an abnormal shape is formed. Can be configured to perform.

According to the second aspect of the present invention, when a disconnection or the like occurs around the motor, the current waveform is not generated, so that this can be detected. Also, by checking the standard current waveform when the motor is in a normal state in advance and comparing it with this, you can know the abnormal waveform.In the case of an abnormal waveform, rust etc. has occurred. As a cause, it is assumed that the motor cannot rotate smoothly, but such a defective state can be detected. In particular, by using the current waveform of the normal state of the motor, it becomes possible to detect defects and failures with high accuracy based on the motor characteristics. In this abnormal waveform determination, it is preferable to set an allowable range based on the normal current waveform in consideration of deterioration with time of the motor, noise, and the like.

According to a third aspect of the present invention, in the seat belt device according to the first or second aspect, the failure determination means generates a counter electromotive current exceeding a certain value within a predetermined time after stopping the motor. A configuration may be adopted in which the determination of failure is executed when no detection is made.

According to the third aspect of the present invention, since the back electromotive current generated within the time after the motor is stopped is used to determine the failure, if there is a failure that cannot be detected by the current waveform. But it can be detected. Of course, the failure determination may be performed based on one of the current waveform and the counter electromotive current when the motor is idling. With respect to this back electromotive current, a reference current waveform may be confirmed in advance so that a failure can be found, but it is also possible to make a failure determination focusing only on the presence or absence of the back electromotive current.

The above object is to provide a seatbelt device having a pretensioner mechanism for retracting a seatbelt in an emergency as described in claim 4, and a motor for retracting the seatbelt of the seatbelt retractor. A belt set detecting means for detecting that the occupant has set a seat belt, and when the belt set detecting means detects the setting of the seat belt, the seat belt is pulled out from the seat belt retractor. This is also achieved by a seatbelt device including a failure determination unit that determines the presence or absence of a failure based on the voltage generated in the motor.

According to the fourth aspect of the present invention, when the belt set detecting means detects that the buckle of the seat belt has been set, the failure determining means determines whether or not there is a failure by the voltage generated by pulling out the seat belt. Since the determination is made, it is possible to know that a failure has occurred in the motor or the drive circuit that drives the motor. The present invention can also be provided as a seat belt device having a pretensioner mechanism that always functions effectively.

The present invention focuses on the fact that the rotor of the motor is forcibly rotated when the seat belt is pulled out, and the motor serves as a kind of generator to generate electricity. A new power supply or the like is provided. It is possible to determine the presence / absence of a failure with a simple configuration in which a voltage detection circuit is added to both wires from the motor.

Further, as described in claim 5, in the seat belt device according to claim 4, the failure determination means can be configured to execute a failure determination when the voltage is not generated. .

According to the fifth aspect of the present invention, since the presence or absence of the voltage generated by the motor when the seat belt is pulled out is checked, it is possible to determine the failure around the motor with a simple structure.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a schematic configuration of a seat belt device 1 having a pretensioner mechanism of the first embodiment.

In FIG. 1, a seat belt retractor shown by reference numeral 10 is shown in a simplified manner, but a reel frame,
It has a well-known configuration such as a reel shaft, and the seat belt 11 is wound around the reel shaft and can be wound and pulled out.

The reel shaft (not shown) of the seat belt retractor 10 is connected to the rotor of the motor 2 via the power transmission 3. The power transmission 3 is formed of, for example, a clutch mechanism, and can form a state (ON state) in which the rotational driving force of the motor 2 is transmitted to the seat belt retractor 10 side and a state (OFF state) in which it is disconnected. It is like this. The operation of the power transmission 3 is C for controlling the pretensioner mechanism of the seat belt device 1 as a whole.
It is controlled by a PU (Central Processing Unit) 5. When the power transmission 3 is turned on, the motor 2
Is transmitted to the seat belt retractor 10 side to wind the seat belt 11. On the contrary, when the power transmission 3 is in the off state, the driving force of the motor 2 is not transmitted to the seat belt retractor 10 side, and the so-called motor idle state occurs.

The motor 2 is drive-controlled by a drive circuit 4 which is controlled by the CPU 5. And
Between the power supply 15 for driving the drive circuit 4,
A resistor 16 for detecting the power supply current is provided. further,
A current detection circuit 6 for detecting the state of current at both ends of the power supply current detection resistor 16 is provided. The current detection circuit 6 supplies the detected current waveform to the CPU 5.

Further, in this embodiment, when the vehicle ignition (I / G) switch 7 is turned on, the CPU 5 determines whether or not a failure has occurred in the motor 2 or the drive circuit 4. . The current waveform detected by the current detection circuit 6 when the motor 2 is idled is used for this determination. This determination method will be described later.

In this embodiment, the CPU 5 is the motor 2
A warning indicator lamp 9 is provided to inform the occupant when it is determined that the drive circuit 4 or the drive circuit 4 has a failure.

In the seat belt device 1 of this embodiment, the I / G
Every time the switch 7 is turned on, the CPU 5 causes the power transmission 3
Of the motor 2 is started by turning off the power transmission of
Determine if there is any failure. Further, the CPU 5 also detects a counter electromotive current generated when the motor 2 is stopped. In this way, the counter electromotive current at the time of stop is also used for the failure determination, so that the states of the motor 2, the drive circuit 4 and the like can be more surely confirmed.

FIG. 2 is a diagram showing an outline of an example H bridge circuit that can be adopted as the drive circuit 4. FIG. 2 shows a power supply 15 and a power supply current detection resistor 16 corresponding to FIG.
Is shown.

When the motor 2 is rotated (normally rotated) in the direction for winding the seat belt in FIG. 2, the CPU 5 turns on the transistors 41 and 42 to cause the current supplied from the power source 15 to flow in the direction of the arrow NR to cause the motor to rotate. Rotate 2. However, when the power supply to the motor 2 is stopped, the rotor of the motor 2 tries to continue rotating due to inertial force.
An attempt is made to keep the current flowing in the direction of arrow NR. However, when the power supply is stopped, all the transistors are turned off, so that the current flows backward to the power source through the diodes 45 and 46 (back electromotive current). This is because the motor 2 temporarily acts as a generator.

Therefore, when the current detection circuit 6 detects a change in the current across the resistor 16 for detecting the power supply current when the motor 2 is started and preferably when the motor 2 is stopped,
It is possible to detect whether or not the drive circuit 4 is functioning normally. That is, if the wiring in the drive circuit 4 is broken or the transistor or the like has an abnormality, it is reflected in the current waveform or the back electromotive force. Therefore, the presence or absence of a failure can be determined by monitoring these.

Next, the principle of the determination method used in this embodiment will be described with reference to FIG. FIG. 3 is a diagram showing a reference (standard) waveform example of the current waveform detected by the current detection circuit 6.

In FIG. 3, when the power transmission 3 is turned off and electric power is supplied from the power source to idle the motor 2, the inrush current PRC due to the motor immediately after starting is greatly increased. When the motor 2 enters a steady driving state after the predetermined time, the current waveform also becomes the steady current waveform COC. Therefore, the inrush current PRC immediately after the start of the used motor and the steady-state current CO in the steady state
It is possible to set the reference current waveform by previously confirming C, and a predetermined time or the like until the inrush current PRC shifts to the steady current COC. By comparing the reference current waveform and the actually detected current waveform, it can be confirmed whether the motor 2 or the like is functioning normally. Of course, it can be determined that there is an abnormality when the current waveform does not occur.

For example, when the motor 2 is stuck and cannot rotate due to rust or dust, the state of the inrush current PRC is maintained and an abnormal current waveform as shown by the dotted line X is obtained.
Therefore, the failure of the motor can be detected. Further, even when the wiring is broken or the drive circuit 4 or the like has an abnormality, the current waveform does not exist or the abnormal shape is low, so that it can be detected as a failure.

Next, detection of a failure in the motor 2 or the drive circuit 4 using the counter electromotive current when the motor is stopped will be described. Note that the failure determination using the counter electromotive current complements the failure determination using the current waveform. That is, as described above, the inrush current PRC at the time of starting the motor 2
The failure of the motor 2 and the drive circuit 4 can be detected by monitoring the transition state to the steady-state current COC. However, in the present embodiment, the generation state of the counter-electromotive current that occurs when the motor is stopped is also confirmed. Uses a configuration that reliably detects failures.

When the supply of the electric power to the motor 2 is stopped from the steady state, as shown in the latter stage of the current waveform shown in FIG. 3, the steady state current COC exceeds the current zero and the above-mentioned counter electromotive current goes to the minus side. CEF occurs. If the motor 2 and the drive circuit 4 are functioning normally, the counter electromotive current CEF appears as a constant current waveform, as in the case of the inrush current PRC at the time of starting. The drive circuit 4 of this embodiment is shown in FIG.
As illustrated in FIG.
It is configured so that it can be reversed.

Therefore, the states of the motor 2 and the drive circuit 4 can also be confirmed by confirming the counter electromotive current. For example, when the current waveform is normal, but no back electromotive force is generated, it can be estimated that a part of the drive circuit 4 has an abnormality. Also, by confirming the standard waveform of this back electromotive force, if the back electromotive current is small, it can be confirmed that rotation is disturbed by rust or dust even if the motor 2 does not reach the fixed state. It is also possible to guess. In the seat belt device 1 of the present embodiment, the counter electromotive current is used complementarily, and therefore the failure is detected by the presence or absence of the counter electromotive current.

An example of the failure determination process performed by the CPU 5 in the seat belt device 1 of this embodiment will be shown below. Figure 4
3 is a flowchart showing the processing executed by the CPU 5.

In FIG. 4, when the CPU 5 confirms that the I / G switch 7 is turned on, this routine is started (S100). In addition to turning on the I / G switch 7,
The activation condition may be, for example, the opening / closing of the door on the driver's side or the detection of depression of the brake pedal.

When this routine is started, the CPU 5 turns off the power transmission 3 (S102) and controls the current detection circuit 6 to make the current waveform detectable.

Subsequently, the CPU 5 controls the drive circuit 4 to start (idle-rotate) the motor 2 under a predetermined condition and further stop it (S104). The CPU 5 is supplied with the current waveform detected by the current detection circuit 6 at this time (S10).
6). For example, the CPU 5 compares the current waveform detected here with the standard current waveform when the motor 2 is functioning normally from the ROM and compares it. If the current waveform at the time of starting the motor is abnormal unlike the standard current waveform (S108), the CPU 5 executes the determination of failure (S11).
4). When it is determined in step 108 that there is no abnormality in the current waveform at the time of starting, it is further confirmed in step 110 whether or not there is a back electromotive current when the motor is stopped. When the back electromotive current at the time of stopping the motor is not generated, the CPU 5 determines that there is a failure (S114).

When it is determined that there is a failure as described above (S114), the warning indicator lamp 9 is turned on to alert the occupant that there is an abnormality in the seat belt device (S116), and this routine is ended. If there is no failure in steps 108 and 110, it is determined that there is no failure (S
112), and this routine ends.

Note that the occupant's attention when there is a failure is not limited to the above warning display lighting, but may be an alarm sound or a voice warning.

According to the present embodiment, the motor used for the pretensioner mechanism is periodically idled, and the seatbelt device equipped with the pretensioner mechanism is simply checked by checking the current waveform and the counter electromotive current. It can be used effectively.

Further, a second embodiment of the present invention will be described with reference to FIGS. FIG. 5 is a diagram showing a schematic configuration of a seat belt device including the pretensioner mechanism of the second embodiment. In the second embodiment, attention is paid to the fact that the motor 2 is forcibly rotated when the occupant pulls out the seat belt to generate power to generate a voltage, and the presence or absence of the voltage is used for failure determination. Is.

In FIG. 5 showing the second embodiment,
The same parts as those in FIG. 1 of the first embodiment are designated by the same reference numerals, and the duplicated description will be omitted.

The seat belt device 50 of this embodiment is provided with a voltage detection circuit 55 for detecting the voltage generated from the motor 2 by forcibly pulling out the seat belt. Further, the CPU 51 of this embodiment is also the CPU of the first embodiment.
Similar to the case of 5, the drive control of the entire seat belt device 50 is executed. However, the CPU 51 monitors that the buckle switch 52 that detects that the buckle of the seat belt has been set is turned on. When the buckle switch 52 is turned on, the CPU 51 determines whether or not the voltage is detected by the voltage detection circuit 55 within a predetermined time immediately before the buckle switch 52 is turned on.

Generally, an occupant sits on the seat belt,
It is unknown when to pull out the seat belt. Therefore, the CPU 51 controls the seat belt buckle switch 52.
Starting from the time when is turned on, it is checked whether the voltage detection circuit 55 has detected the voltage retroactively from this time. In addition,
In order to confirm the voltage data detected by the voltage detection circuit 55, a memory for storing the voltage data is provided and a CPU is provided.
It suffices if the device 51 is configured so that the voltage can be confirmed later.

An example of the failure determination process performed by the CPU 51 in the seat belt device 50 of this embodiment will be described below. Figure 6
3 is a flowchart showing a process executed by the CPU 51. In FIG. 6, when the CPU 51 confirms that the I / G switch 7 is turned on, this routine is started (S
200) When this routine is activated, the CPU 51 controls the voltage detection circuit 55 to enable voltage detection, and also monitors whether the buckle switch of the seat belt is turned on at a predetermined cycle (S202, S204).

In step 204, when the CPU 51 confirms that the buckle switch is turned on, it accesses the memory storing the voltage data and the voltage detection circuit 55 detects the voltage within a time period which is a fixed time back from that time. Check whether it was done or not. That is, it is confirmed whether or not a voltage is generated by pulling out the seat belt (S20).
6).

When it is confirmed in step 206 that the voltage has been generated, the CPU 51 determines that there is no failure (S208), and ends this routine. On the other hand, when no voltage is generated in step 206, it is determined that there is a failure (S210), and the warning indicator lamp 9 is turned on to alert the occupant that there is an abnormality in the seat belt device (S212). To finish.

In the judgment by the CPU 51 shown in FIG.
It is possible to realize a simple failure determination of the motor 2 or the like depending on whether the voltage detection circuit 55 detects the voltage, that is, whether or not the voltage is generated by pulling out the seat belt.

Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the specific embodiments, and various modifications are possible within the scope of the gist of the present invention described in the claims. Can be modified and changed.

In the claims, the motor driving means is the driving circuit 4, the driving force transmitting means is the power transmitting device 3, the failure determining means is the current detecting circuit 6 and the CPU 5, and the voltage detecting circuit 55 and the CPU 51. The belt set detection means correspond to the buckle switches 52, respectively.

[0052]

As is apparent from the above detailed description, according to the invention described in claim 1, it is possible to determine whether or not there is a failure on the basis of a current waveform obtained by forming a state in which the motor idles. Since the means is provided, it is possible to know that a failure has occurred in the motor or the drive circuit that drives the motor. Therefore, it is possible to provide the seat belt device including the pretensioner mechanism that always functions effectively.

According to the second aspect of the invention, the abnormal waveform can be known and the failure can be determined by confirming the standard current waveform in advance and comparing it.

According to the third aspect of the invention, it is possible to determine the failure by utilizing the back electromotive current generated within the time after the motor is stopped.

According to the fourth aspect of the invention, since the failure determination means determines the presence or absence of the failure based on the voltage generated by pulling out the seat belt, it is possible to determine that the failure has occurred in the motor or the drive circuit for driving the motor. I can know.

According to the fifth aspect of the invention, since the presence or absence of the voltage generated by the motor when the seat belt is pulled out is checked, it is possible to determine the failure around the motor with a simple structure.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of a seat belt device including a pretensioner mechanism of a first embodiment.

FIG. 2 is a diagram showing an outline of an example H-bridge circuit that can be used as a drive circuit.

FIG. 3 is a diagram showing a reference waveform example of a current waveform detected by a current detection circuit.

FIG. 4 is a flowchart showing a process executed by the CPU of the first embodiment.

FIG. 5 is a view showing a schematic configuration of a seat belt device including a pretensioner mechanism of a second embodiment.

FIG. 6 is a flowchart showing a process executed by a CPU of the second embodiment.

[Explanation of symbols]

1 seat belt device 2 motor 3 power transmission 4 drive circuit 5 CPU 6 Current detection circuit 7 Ignition switch 10 Seat belt retractor

Claims (5)

[Claims] 1. A seatbelt device having a pretensioner mechanism for retracting a seatbelt in an emergency, the motor being for retracting a seatbelt of a seatbelt retractor, and receiving power supplied from a power source, The motor driving means for driving the motor, the driving force transmitting means for switching between connecting and disconnecting the driving force transmitted from the motor to the seat belt retractor side, and the driving force transmitting means. A failure determination means for determining the presence or absence of a failure based on a current waveform generated when the motor driving means drives the motor in a state where the driving force from the motor to the seat belt retractor is cut off. A seat belt device characterized by the following. 2. The seat belt device according to claim 1, wherein the failure determination means executes a failure determination when the current waveform does not occur or when the current waveform has an abnormal shape. Seat belt device. 3. The seat belt device according to claim 1, wherein the failure determination means detects a failure when a counter electromotive current exceeding a certain value is not detected within a predetermined time after stopping the motor. A seat belt device, characterized in that the determination of (1) is executed. 4. A seatbelt device having a pretensioner mechanism for retracting a seatbelt in an emergency, comprising: a motor for retracting the seatbelt of the seatbelt retractor, and an occupant setting the seatbelt. The belt set detection means for detecting, and when the belt set detection means detects the setting of the seat belt, a failure occurs based on the voltage generated in the motor due to the seat belt being pulled out from the seat belt retractor. A seatbelt device comprising: a failure determination unit that determines the presence or absence of the seatbelt. 5. The seat belt device according to claim 4, wherein the failure determination unit executes a failure determination when the voltage is not generated.