JPH0537723Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention is for use in passenger protection where the tip of the webbing for restraining an occupant is guided by a guide rail etc. installed on the vehicle body, and the webbing is automatically unattached to the occupant. The present invention relates to a seat belt device control circuit that controls a seat belt device.

[Prior Art] In this type of seatbelt device, as shown in FIG. 10, an anchor plate 20 is connected to the tip of the webbing 14 pulled out from a take-up device 18 via a connecting plate 19. The anchor plate 20 is guided by a guide rail 22 provided on the vehicle body and is movable in the longitudinal direction of the vehicle.
The seat belt device control circuit activates the motor 44 when the door switch, which is the boarding/exiting detection means, detects that the door is open.
The anchor plate 20 is rotated in the normal direction to move the anchor plate 20 toward the front of the vehicle, and the webbing device for the occupant 12 is released. Furthermore, when the door switch detects that the door is closed, the motor 44 is reversed to move the anchor plate 20 toward the rear of the vehicle, allowing the occupant
Webbing 14 is attached to 2.

However, if the occupant 12 moves his or her upper body while the anchor plate 20 is moving, the webbing 1
The upper part of passenger 12 may interfere with the neck and head of passenger 12.
2 may cause discomfort. Also, motor 4
4 will also be burnt out.

[Problems to be solved by the invention] The present invention has a simple structure and does not cause discomfort to the occupant even if the webbing interferes with the occupant's neck or head when the occupant moves his or her upper body while the tip of the webbing is moving. The motor can be stopped in response to the interference to avoid causing interference or burning out the motor.
Another object of the present invention is to provide a seat belt device control circuit that can automatically return the motor to drive, and can also stop and return the motor in a good manner.

[Means for solving the problem] In the seat belt device control circuit according to the present invention,
a motor current detection resistor connected in series to the motor that moves the webbing tip; a comparator that receives the voltage across the terminals of the motor current detection resistor, compares it with a reference voltage, and outputs a motor overcurrent signal; The motor temporarily stops the motor for a predetermined period of time when a motor overcurrent signal is input after a predetermined period of time has elapsed after starting the motor.

[Function] If the occupant moves his or her upper body while the tip of the webbing is moving, and the motor is mechanically restrained, the voltage across the terminals of the motor current detection resistor will exceed a certain value, and the comparator will detect a motor overload. A current signal is output.
When this motor overcurrent signal is output after a predetermined period of time has elapsed after the motor is started, the motor temporary stop means cuts off the power supply to the motor for a predetermined period of time.

Therefore, even if the occupant moves his or her upper body while the webbing tip is moving and the webbing interferes with the occupant's neck or head, the occupant will not feel uncomfortable or the motor will not burn out. In addition, the temporary stop means is activated for a certain period of time and the motor is turned off by inputting an overcurrent signal, regardless of the overcurrent itself, so the motor can be turned off and turned back on instantly, and the motor can be turned on and off. The deterioration of the motor caused by the time it takes for the motor to turn on is effectively prevented, the motor is automatically turned back on, and furthermore, the temporary stop means does not operate until a certain period of time has elapsed after the motor has been started, and the motor stops running. Since the motor does not turn off, malfunction due to the starting current that occurs when starting the motor is prevented, and the motor can be stopped and returned to driving smoothly.

[Example] FIG. 2 shows a side view of a seat belt device to which this example is applied.

The occupant 12 seated on the seat 10 wears the webbing 1
4 can be installed automatically. One end of this webbing 14 is wound up with a predetermined biasing force onto a winding device 18 attached to a floor 16 in the center of the vehicle. This take-up device 18 has a built-in inertia lock mechanism that instantly stops pulling out the webbing 14 in case of a vehicle emergency.

The other end of the webbing 14 is locked to an anchor plate 20 via a connecting plate 19, and the anchor plate 20 is guided along a guide rail 22 in the longitudinal direction of the vehicle.
The guide rail 22 has a guide rail main body 24 whose center portion is horizontally disposed on a roof side member 26 forming a part of a side wall of the vehicle body, and whose front end portion is attached along a front pillar 28 and is inclined. Further, the rear end of the guide rail main body 24 is bent at a substantially right angle, faces downward from the vehicle, and is fixed to the center pillar 30.

As shown in FIG. 3, the guide rail main body 24 has a substantially U-shape with a groove 32 opening toward the bottom of the vehicle. The bottom of this groove 32 is enlarged in diameter to accommodate a head 34 formed at the tip of the anchor plate 20. This head 34 has the role of reliably transmitting the tension generated in the webbing 14 to the roof side member 26 in the event of a vehicle emergency.

Further, a tape storage groove 36 whose width is partially enlarged is formed in the middle part of the groove 32 in the height direction, and a flexible tape 38 is slidably guided in the longitudinal direction of the guide rail 22. There is.

As shown in FIG. 4, this flexible tape 38 is a thick elongated material, and has a plurality of openings 40 formed along its length. The anchor plate 20 passes through one of these openings 40 so that the anchor plate 20 moves together with the flexible tape 38. In addition, flexible tape 3
8 is adapted to mesh with a sprocket foil 42 attached to the lower part of the center pillar 30, and this sprocket foil 42 rotates under the driving force of a motor 44 to longitudinally extend the flexible tape 38. It is designed to move in the direction.
Sprocket foil 42 is housed in a housing 46 attached to the lower portion of center pillar 30 to ensure engagement with flexible tape 38. A tape guide rail 47 is provided between the sprocket housing 46 and the guide rail body 24. Further, a tape guide rail 47 is also wound around the side of the sprocket housing 46 opposite to the guide rail main body 24.

The guide rail main body 24 has strips 48 abutted near the entrances of the grooves 32, as shown in FIG. These strips 48 are such that a protrusion 50 provided therein is received in a groove 52 formed in the side of the guide rail body 24. The tips of the strips 48 protrude from the lower end of the guide rail body 24 and abut against each other to close the entrance of the groove 32, but when the anchor plate 20 passes, they are separated to ensure a passage for the anchor plate 20. I'm starting to be able to do it.

The upper parts of the guide rail body 24 and the strip 48 are covered by a cover 54. cover 54
A mounting plate 56 is fixed to the side surface of the roof side member 26, and the mounting plate 56 is screwed to the roof side member 26 with bolts 58. As shown in FIG. 2, a release detection switch 62 is disposed at the vehicle front end of the guide rail body 24, and the anchor plate 20
It is designed to detect the front limit of the movement of . Further, a mounting detection switch 60 is disposed at the other end of the guide rail main body 24, and is adapted to detect the rear limit of movement of the anchor plate 20. A seating detection switch 64 is disposed on the seat cushion of the seat 10, and is configured to detect whether the occupant 12 is seated on the seat 10. Although not shown in FIG. 2, a door switch (see FIG. 1) for detecting opening and closing of the door is provided on the vehicle body.

Next, a seat belt device control circuit for controlling the attachment and release of the seat belt device configured as described above will be explained with reference to FIG.

The common terminal of the door switch 66 is grounded,
The closing side terminal 66A is the mounting position detection switch 6.
0, is connected to the input terminal _P1 of the microcomputer 68 via the seat switch 64. Therefore, when the door is closed, the occupant is seated on the seat, and the seat switch 64 is closed, the input terminal _P1 becomes a low level (hereinafter referred to as "L"). When the anchor plate 20 moves to the rear of the vehicle and the webbing installation is completed, the installation position detection switch 60 is opened and the input terminal _P1 becomes high level (hereinafter referred to as "H").

Further, the open side terminal 66B of the door switch 66 is connected to the input terminal _P2 of the microcomputer 68 via the release position detection switch 62. Therefore, when the door is opened, input terminal _P2 becomes L,
When the anchor plate 20 moves toward the front of the vehicle and the webbing is released, the release position detection switch 62 is opened and the input terminal _P2 becomes H.

A motor forward rotation signal is output from the output terminal P ₃ of the microcomputer 68, and the drive circuit 7
The C contact 78 can be actuated by energizing the relay coil 74 of the relay 72 via 0. In addition, a motor reversal signal is output from the output terminal _P4 of the microcomputer 68.
By exciting the relay coil 76 of the relay 72 via the drive circuit 70, the C contact 80 can be operated. The motor 44 is connected to the common terminals of the C contact 78 and the C contact 80. Normally open terminal 78A of C contact 78 and C contact 8
The normally open terminal 80A of 0 is connected to a +B volt terminal of a power supply circuit (not shown). Further, a normally closed terminal 78B of the C contact 78 and a normally closed terminal 80B of the C contact 80 are grounded via a resistor 82. Therefore, when the relay coil 74 is energized and the common terminal of the C contact 78 and the normally open terminal 78A are electrically connected, the motor 44 rotates forward, and the relay coil 76 is energized and the C
Common terminal of contact 80 and normally open terminal 8
When 0A is made conductive, the motor 44 rotates in reverse.

The current flowing through the motor 44, ie, the current flowing through the resistor 82, is proportional to the voltage across the terminals of the resistor 82.
The voltage across the resistor 82 is supplied to a comparator 90. This voltage is the resistance value R ₂ , R ₃
The voltage is compared with a reference voltage determined by , and is supplied to the input terminal P ₈ of the microcomputer 68 . That is, when the rate of change of the current flowing through the motor 44 exceeds a certain value, the input terminal _P8 becomes H.

In addition, a speaker 97, an indicator light 98, and an indicator light 99 are connected to the microcomputer 68 via a drive circuit 96, and an electronic sound is emitted from the speaker 97 when necessary conditions are set, such as when the movement of the anchor plate 20 is restricted. The warning lights 98 and 99 are flashed or lit to issue a warning to the occupants.

Next, an outline of the operation of the first embodiment constructed as described above will be explained with reference to the diagram shown in FIG. 5 and the waveform diagram shown in FIG. 6.

When the passenger exits the vehicle, when the door is opened, the open side terminal 66B of the door switch 66 is grounded, and the input terminal _P2 of the microcomputer 68 becomes L (FIG. 6A). The microcomputer 68 reads the falling potential of the input terminal _P2 and sets the output terminal _P3 to H.
Then, the relay coil 74 is energized to rotate the motor 44 in the normal direction (FIG. 6b). As a result, the motor 44
A large starting current flows through the input terminal (Fig. 5 C).
A pulse is input to _P8 (Fig. 6 D). The microcomputer 68 ignores even if the input terminal _P8 becomes H until a predetermined time _t1 has elapsed since the motor 44 was turned on. After this time _t1 elapses, when the occupant tries to get off the vehicle and moves his or her upper body, the webbing 14 interferes with the occupant's neck and head, and the anchor plate 2
When the movement of 0 is restrained, the impedance of the motor 44 decreases, the current flowing through the resistor 82 increases (FIG. 5E), and the input terminal _P8 becomes H (FIG. 6F). Microcomputer 68 is an input terminal
When _P8 becomes H, output terminal _P3 becomes L and motor 4
4 is turned off for a certain period of time t ₂ (Fig. 6, G). Then, the output terminal _P3 is set to H again, the motor 44 is turned on, and the above process is repeated.

Therefore, even if the occupant moves his or her upper body while the webbing tip is moving and the webbing interferes with the occupant's sound or head, the motor rotation is instantly stopped and the webbing stops moving, causing no harm to the occupant. It does not give a pleasant sensation or burn out the motor. When the anchor plate 20 moves to the position of the release position detection switch 62, the release position detection switch 62 is opened and the input terminal _P2 becomes H (Fig. 6, h). . The microcomputer 68 reads that the input terminal _P2 has become H, and sets the output terminal _P3 to L, turning off the motor 44 (FIG. 6-1). The same applies when a passenger rides the vehicle.

Next, details of the above operation will be explained according to the control flowcharts shown in FIGS. 7 and 8.

First, the RAM work area and output (output terminals P ₃ to _{P 7} of the microcomputer 68 are set to "L").
(output) (step 100).
It waits for input terminal _P1 or input terminal _P2 to become L (steps 101, 104). When it reads that input terminal P ₂ has become L, output terminal P ₃ is set to H and motor 4 is turned on.
4 is rotated in the normal direction, and the output terminal _P6 is set to H to turn on the indicator light 98 (step 102). This output is self-held until L is output. The same applies to other outputs. When it is read that input terminal P ₁ has become L, output terminals P ₄ and P ₇ are set to H.
The motor 44 is rotated in the reverse direction and the indicator light 99 is turned on (step 106). Step 102 or Step
After completing the process in step 106, the value of _t0 is set to _t1 (step 108), and the soft timer subroutine shown in FIG. 8 is processed (step 110). That is, as shown in Figure 8, the value of t ₀ is decremented (step
200), this is repeated until the value of _t0 becomes zero, and the process returns (step 202). In this way, the starting current flows through the motor, causing the input terminal _P8 to
can be ignored. Next, it is read whether the input terminal _P8 is set to H, that is, whether the movement of the anchor plate 20 is restricted. When the input terminal P ₆ is at H (step 112), a warning sound is emitted from the speaker 97, and when the input terminal P ₁ is at L, the indicator light 98 is turned on.
When the input terminal _P2 is L, the indicator light 99 is blinked (step 114). Next, the output terminal P ₃ and the output terminal P ₄ are set to L, and the motor 44 is turned off. Note that either output terminal P ₃ or output terminal P ₄ is already at L.
It is becoming. Then set the value of t ₀ to t ₂ (step
118), it processes the subroutine shown in FIG. 8 and waits for a certain period of time _t2 to elapse (step 120). Next, the sound emitted from the speaker 97 is turned off, and the input terminal P ₁
When the input terminal P2 is at L, the indicator lamp 98 is turned on, and when the input terminal _P2 is at L, the indicator lamp 99 is turned on (step 122). Then, when the motor is operated again, the result shown in Figure 5
In order to prevent the H of _P8 from being read during time _t1 , the process returns to step 101. Input terminal _P8 in step 112
is L, when input terminal P ₁ is L, output terminal P ₃ is set to H to rotate the motor 44 in the normal direction (steps 124, 126), and when input terminal P ₂ is L, output terminal P ₄ is set to H. to reverse the motor 44 (steps 128 and 130). Then return to step 112. Note that the outputs of the output terminals P ₃ to _{P 7} are self-maintained, so when the output terminals P ₃ to P ₇ are set to H, there will be no change in the output even if the output terminals P ₃ to _{P 7} are set to H. There isn't. The same applies to the case of L. If both the input terminal _P1 and the input terminal _P2 are at H, the process returns to the first step 100, turns off the motor 44, the indicator light 98, and the indicator light 99, and repeats the above process.

Next, a second embodiment of the present invention will be described with reference to FIG.

In this second embodiment, a thermistor Rx is used in place of the resistor _R2 of the comparator 90. Therefore,
As the ambient temperature rises, the voltage input to the negative input terminal of the operational amplifier, that is, the reference voltage, decreases.
Therefore, the ambient temperature changes and the guide rail 22
Even if the slip resistance of the anchor plate 20 changes due to a change in the viscosity of the grease applied to the anchor plate 20, mechanical restraint of the anchor plate 20 can be detected reliably and without error.

The circuit shown in FIG. 1, which stops the motor for a certain period of time when the motor is mechanically locked, can also be applied to other devices, such as a vehicle window drive device.

[Effect of the invention] In the seatbelt device control circuit according to the invention,
When the voltage across the terminals of the motor current detection resistor connected in series to the motor that moves the webbing tip exceeds the reference voltage, a motor overcurrent signal is output from the comparator, and the motor is started and a certain period of time has elapsed. If this motor overcurrent signal is output later, the motor temporary stop means turns off the motor for a certain period of time, so if the occupant moves his or her upper body while the webbing tip is moving, the webbing may move around the occupant. Even if it interferes with the neck or head, it will not cause discomfort to the occupants or burn out the motor. Furthermore, the configuration is simple.

Furthermore, since the temporary stop means is activated for a certain period of time and the motor is turned off by inputting an overcurrent signal, regardless of the overcurrent itself, the motor can be turned off and turned back on instantly, and the motor can be turned on or turned off instantly. The deterioration of the motor caused by the long time it takes to turn off the motor is effectively prevented, the motor is automatically turned back on, and furthermore, the temporary stop means does not operate until a certain period of time has elapsed after the motor has been started, and the motor stops running. does not turn off, which prevents malfunction due to the starting current that occurs when the motor starts, and prevents the motor from stopping or stopping.
This provides the effect that drive recovery can be performed satisfactorily.

In particular, since it is often expected that the webbing will interfere with the occupant, this is extremely effective in eliminating the discomfort caused to the occupant and preventing the motor from burning out.

[Brief explanation of the drawing]

Fig. 1 is a seat belt device control circuit diagram according to an embodiment of the present invention, Fig. 2 is a side view showing a state in which the seat belt device is worn by an occupant, and Fig. 3 is an anchor plate placed at the - line position in Fig. 2. Figure 4 is an exploded perspective view showing the relationship between the sprocket and the flexible tape that drives the anchor plate housed in the guide rail. A diagram showing the current as a function of time, FIG. 6 is an output waveform diagram of the microcomputer 68 corresponding to FIG. 5, FIGS. 7 and 8 are control flow charts, and FIG. FIG. 10, a partial diagram of a control circuit showing an embodiment, is a side view corresponding to FIG. 2 showing problems in the conventional example. 14... Webbing, 60... Installation position detection switch, 62... Release position detection switch, 64...
...Seat switch, 66...Door switch, 82
...Resistor (for motor current detection), 90...Comparator, Rx...Thermistor.

Claims (1)

[Claims for Utility Model Registration] (1) A motor current used in a seat belt device that moves the webbing tip in the longitudinal direction of the vehicle to attach and release the webbing, and that is connected in series to the motor that moves the webbing tip. A detection resistor, a comparator that receives the voltage across the terminals of the motor current detection resistor, compares it with a reference voltage, and outputs a motor overcurrent signal. A seat belt device control circuit comprising: motor temporary stop means that turns off the motor for a certain period of time when an input is received. (2) The seat belt device control circuit according to claim 1, wherein the reference voltage input to the comparator is lowered as the temperature rises using a thermistor.