JPH056208Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention is for use in passenger protection, where the tip of the webbing for passenger restraint is guided by a guide rail, etc. installed on the vehicle body, and the webbing is automatically released from the passenger. The present invention relates to a seat belt device control circuit that controls a seat belt device.

[Conventional technology]

In this type of seatbelt device, as shown in FIG. 6, an anchor plate 20 is connected to the tip of the webbing 14 pulled out from the 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 is configured to rotate the motor 44 in the forward direction to move the anchor plate 20 toward the front of the vehicle and release the webbing device for the occupant 12 when the door switch, which is the ingress/egress detection means, detects that the door is open. There is. 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, and
The webbing 14 is attached to the webbing 14.

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.

Also related to this is a passive system that detects the rotational speed of the motor that moves the anchor plate, and when the rotational speed falls below a certain value, it determines that the motor is overloaded and stops driving the motor. A control circuit for a seat belt motor has been proposed (see Japanese Patent Laid-Open No. 58-29390).

However, in this passive seat belt motor control circuit, the overload standard varies depending on environmental conditions. For example, if the motor has deteriorated over time or if a load is constantly applied to the motor due to adhesion of dust, etc., the rotational speed of the motor will be reduced even when the webbing is not interfering with the passenger.
As a result, an inconvenience arises in that even if a small load is applied, the motor is judged to be overloaded and the motor is stopped.

Additionally, a seat belt device configured to stop driving the motor when a certain amount of overcurrent flows through the motor has been proposed (Utility Model Application Publication No. 56-39341, Utility Model Application No. 55-155661). ), but like the above, these also had the disadvantage of unstable operation due to fluctuations in environmental conditions.

[The problem that the idea aims to solve]

This invention ensures that 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, it will not cause discomfort to the occupant or burn out the motor, regardless of changes in environmental conditions. It is an object of the present invention to provide a seat belt device control circuit that does not cause

[Means to solve the problem]

In the seat belt device control circuit according to the present invention,
Detection means used in a seat belt device that attaches and releases the webbing by moving the webbing tip in the longitudinal direction of the vehicle, and detects that the rate of change of the current flowing through the motor that moves the webbing tip is equal to or higher than a certain value. and a motor temporary stop means that turns off the motor for a certain period of time when it is detected that the rate of change in the current flowing through the motor is equal to or higher than a certain value after a certain period of time has passed since the motor was started. .

[Function] If the occupant moves his or her upper body and interferes with the webbing while the tip of the webbing is moving, a large load is applied to the motor that moves the tip of the webbing.
The current flowing through the motor varies widely. Therefore, in this invention, overload of the motor is detected by detecting that the rate of change of the current flowing through the motor that moves the tip of the webbing exceeds a certain value, and the motor is started and the current flowing through the motor is started after a certain period of time has elapsed. When it is detected that the rate of change of current is above a certain value, that is, when an overload of the motor is detected, the motor is turned off for a certain period of time.

Therefore, 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 movement of the webbing tip is stopped for a certain period of time, which may cause discomfort to the occupant. The motor will not burn out.

In addition, the present invention detects overload by detecting that the rate of change of the current flowing through the motor is above a certain value, so that the load is constantly applied to the movement of the webbing tip due to deterioration over time, etc. Even if the current flowing through the motor under normal conditions changes due to changes in environmental conditions such as changes in the surrounding environmental temperature or battery voltage, only cases where the webbing interferes with the occupant will be considered an overload. Can be reliably detected.

〔Example〕

FIG. 2 shows a side view of a seat belt device to which this embodiment 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 that is attached to a floor 16 in the approximate 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 and 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 has an enlarged 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 38
A part of the flexible tape 3 is adapted to mesh with a sprocket foil 42 attached to the lower part of the center pillar 30. This sprocket foil 42 rotates under the driving force of a motor 44, and the flexible tape 3
8 in the longitudinal 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. Also, sprocket housing 4
A tape guide rail 47 is also wound around the opposite side of the guide rail main body 24 of No. 6.

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 device is completed, the mounting 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 device 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
By energizing the relay coil 74 of the relay 72 via 0, the C contact 78 can be switched. In addition, the output terminal of the microcomputer 68
A motor reversal signal is output from P ₄ , and is sent to the relay coil 7 of the relay 72 via the drive circuit 70.
By energizing the C contact 80, the C contact 80 can be switched.

The motor 44 is connected to the common terminals of the C contact 78 and the C contact 80. The normally open terminal 78A of the C contact 78 and the normally open terminal 80A of the 8 C contacts are +B of a power supply circuit (not shown).
Connected to bolt terminals. In addition, C contact 78
The normally closed terminal 78B of the C contact 80 and the normally closed terminal 80B of the C contact 80 are grounded via a resistor 82. Therefore, relay coil 74
When the relay coil 76 is energized and the common terminal of the C contact 78 and the normally open terminal 80A are electrically connected, the motor 44 rotates in the normal direction.When the relay coil 76 is energized and the common terminal of the C contact 80 and the normally open terminal 80A are electrically connected, the motor 44 rotates in the reverse direction. I'm starting to do that.

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 between the terminals of the resistor 82 is supplied to the voltage amplification circuit 86 of the overcurrent detection circuit 84 and amplified, and then the direct current component is removed by the differentiating circuit 88 so that only the partial current component is supplied to the comparator 90. It's getting old. This AC component voltage is compared with a reference voltage determined by the resistance values ₂ and ₃ , 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 this way, the overload of the motor 44 can be reduced by
Since the motor overload is detected based on the amount of change in the current flowing through the motor 44, motor overload can be reliably detected even if the normal current flowing through the motor 44 changes due to changes in temperature or the like.

Further, a speaker 97, an indicator light 98, and an indicator light 99 are connected to the microcomputer 68 via a drive circuit 96, and when the movement of the anchor plate 20 is restricted, the speaker 97 emits an electronic sound. When the system is released, an indicator light 98 is flashed, and when the system is installed, an indicator light 99 is flashed to issue a warning to the occupants. Normally, the indicator light 98 is turned on when the device is released, and the indicator light 99 is turned on when the device is attached.

Next, an outline of the operation of this 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 rising 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 starting current flows through (Figure 5C), and a pulse is input to input terminal _P8 (Figure 6D). The microcomputer 68 turns on the motor 44 for a certain period of time t1 _.
Until this time has elapsed, even if the input terminal _P8 becomes H, this is ignored.

After this time t ₁ has elapsed, when the webbing 14, which the occupant has moved his or her upper body around when attempting to exit the vehicle, interferes with the neck and head of the occupant 12 and restricts the movement of the anchor plate 20, the impedance of the motor 44 decreases. The current flowing through the resistor 82 increases (the fifth
Figure E), input terminal _P8 becomes H (Figure 6F). When the input terminal _P8 becomes H, the microcomputer 68 changes the output terminal _P3 to L, turning off the motor 44 for a certain period of time _t2 (FIG. 6, T). 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 neck or head, the occupant will not feel uncomfortable or the motor will not burn out.

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 is on board.

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 input terminal P ₂ is read as 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 the input terminal P ₁ has become L, the output terminals P ₄ and P ₇ are set to H, the motor 44 is reversed, and the indicator lamp 99 is turned on (step 106).

When the processing of step 102 or step 106 is completed, 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 FIG. 8, the value of t ₀ is decremented (step 200), this is repeated until the value of t ₀ becomes zero, and the process returns (step 200).
202). In this way, it is possible to ignore the fact that the input terminal _P8 becomes H due to the starting current flowing through the motor.

Next, check whether input terminal _P8 is at H level.
That is, it is read whether the movement of the anchor plate 20 is restricted. If the input terminal P ₈ is at H (step 112), the speaker 97 emits a warning sound, when the input terminal P ₁ is at L, the indicator light 98 is turned on, and when the input terminal P ₂ is at L, the display is displayed. Make the light 99 blink (step 114). Then output terminal P ₃
Then, the output terminal _P4 is set to L to turn off the motor 44. Note that either the output terminal P ₃ or the output terminal P ₄ is already set to L. Next _, the value of t ₀ is set to t ₂ (step 118), the subroutine shown in FIG.
120). Next, the sound emitted from the speaker 97 is turned off (step 122). Next, when the motor is operated again, the process returns to step 101 in order to avoid reading "H" in _P8 for time _t1 .

When the input terminal _P8 is L in step 112, when the input terminal _P1 is L, the output terminal _P3 is set to H to rotate the motor 44 in the normal direction (steps 124, 126), and when the input terminal _P2 is L At times, the output terminal _P4 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 input terminal P ₁ and input terminal P ₂ are both H, return to the first step 100 and start motor 4.
4. Turn off the indicator light 98 and indicator light 99, and repeat the above process.

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 power window drive device for a vehicle.

[Effect of idea]

In the seat belt device control circuit according to the present invention,
When the detecting means detects that the rate of change of the current flowing through the motor exceeds a certain value after a certain period of time has elapsed after starting the motor, the motor is turned off for a certain period of time and the movement of the webbing tip is stopped. Therefore, even if the webbing interferes with the occupant's neck or head when the occupant moves his or her upper body while the webbing tip is moving, the occupant may feel uncomfortable or the motor may burn out, regardless of changes in environmental conditions. It has an excellent effect of not causing any problems.

[Brief explanation of the drawing]

Fig. 1 is a seat belt device control circuit 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 moved to the - line position in Fig. 2. Fig. 4 is an exploded perspective view showing the relationship between the flexible tape that drives the anchor plate housed in the guide rail and the sprocket, and Fig. 5 shows the current flowing through the motor. FIG. 6 is a diagram showing the output waveform of the microcomputer 68 corresponding to FIG. 5, FIGS. 7 and 8 are control flow charts, and FIG. FIG. 3 is a side view corresponding to FIG. 2 shown in FIG. 10... Sheet, 14... Webbing, 22...
... Guide rail, 60 ... Installation position detection switch, 62 ... Release position detection switch, 64 ... Seat switch, 66 ... Door switch, 84 ...
Overcurrent detection circuit, 86...Voltage amplification circuit, 88...
...Differential circuit, 90...Comparator.

Claims (1)

[Scope of utility model registration request] Detection means used in a seatbelt device that attaches and releases the webbing by moving the webbing tip in the longitudinal direction of the vehicle, and detects that the rate of change in the current flowing through the motor that moves the webbing tip is equal to or higher than a certain value. and a motor temporary stop means that turns off the motor for a certain period of time when it is detected that the rate of change of the current flowing through the motor is equal to or higher than a certain value after a certain period of time has elapsed after starting the motor. Seat belt device control circuit.