JPH048057Y2 - - 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. 9, 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 rotates the motor 44 in the forward direction to move the anchor plate 20 toward the front of the vehicle when the door switch, which is a means for detecting getting on and off, detects that the door is open, and releases the webbing from the occupant 12. 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 an overload has been applied to the motor and stops driving the motor. A control circuit for a seat belt motor has been proposed (see Japanese Patent Application 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 deteriorates over time or if a constant load is applied to the motor due to the adhesion of dust, etc., the rotational speed of the motor will decrease even when the webbing is not interfering with the passenger.
As a result, a problem arises in that even if a small load is applied, the motor is judged to be overloaded and the motor is stopped.

[Problems to be solved by the invention] This invention solves the problem of causing discomfort to the occupant or causing the motor to stop 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 is an object of the present invention to obtain a seat belt device control circuit that does not burn out.

[Means for solving the problem] In the seat belt device control circuit according to the present invention,
motor current detection means for detecting a current flowing through a motor that moves a webbing tip; normal current value holding means for holding a current value detected after a certain period of time has elapsed after starting the motor as a normal current value; The motor temporarily stops the motor for a predetermined period of time when the current value detected after the lapse of time is a predetermined value or more than the normal current value.

[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. For this reason, in this invention, the current value flowing through the motor that is detected after a certain period of time has passed after starting the motor is held as the normal current value, and the current value that is detected after the certain period of time has elapsed is a constant value that is higher than the normal current value. If this is the case, that is, if an excessive load is applied to the motor, 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, in this invention, the current value flowing through the motor that is detected after a certain period of time has passed after starting the motor is held as the normal current value, so unlike the case where a preset constant value is used as the normal current value, The normal current value is changed as appropriate according to changes in conditions. For example, if a constant load is applied to the movement of the webbing tip due to aging deterioration, or if the ambient temperature changes and the current flowing to the motor changes, the Normal current value is changed. Therefore, only the case where the webbing interferes with the occupant can be reliably detected as an overload.

[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 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 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 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 compared via the resistor R ₁ (the resistance value is also referred to as resistor R _1. The same applies hereinafter). is supplied to the + input terminal of the device 88. A resistor is connected between this + input terminal and ground.
R ₂ is connected. The output voltage of the voltage amplifier circuit 86 is V _S , and the voltage at the + input terminal of the comparator 88 is V _C
Then, the following formula holds true.

V _C = R ₂ V _S / (R ₁ + R ₂ ) ... (1) On the other hand, the output terminal of the voltage amplifier circuit 86 is connected to the comparator 8 via the transistor Tr ₁ which is a charging switch.
It is connected to the negative input terminal of 8. Further, a capacitor C and a transistor _Tr2 , which is a discharge switch, are connected in parallel between the negative input terminal of the comparator 88 and the ground.

Therefore, when the output terminal P ₉ of the microcomputer 68 is set to L and the transistor Tr ₁ is turned on, the output current of the voltage amplification circuit 86 charges the capacitor C, and the - input terminal voltage of the comparator 88 becomes the voltage of the voltage amplification circuit 86. It becomes equal to the output voltage Vs. Next, when the output terminal P ₉ of the microcomputer 68 is set to H and the transistor Tr ₁ is turned off, the comparator 88 -
Input terminal voltage V _S is maintained. Furthermore, when the output terminal P ₁₀ of the microcomputer 68 is set to H, the charge of the capacitor C is discharged, and the output terminal P ₁₀ is set to L.
When it is set, it can be charged.

The output voltage of the comparator 88 is supplied to the input terminal _P8 of the microcomputer 68, so that motor overload can be detected.

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 a 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), and the output terminal _P10 is set to L to enable charging of the discharged capacitor C (Fig. 6B).
Figure c). A starting current flows through the motor 44 (FIG. 5D), and a pulse is input to the input terminal _P8 (FIG. 6E). The microcomputer 68 controls the motor 44
input terminal P ₈ until a certain period of time t ₁ has elapsed after turning on
Even if becomes H, this is ignored. Then for a certain period of time
The output terminal P ₉ is set to L for only t ₂ to turn on the transistor Tr ₁ and charge the capacitor C. This results in
The output voltage Vs ₀ of the voltage amplification circuit 86 corresponding to the normal current value (normal current value under various conditions such as ambient temperature) flowing through the motor 44 is supplied to the - input terminal of the comparator 88 and held there. After this time t ₁ has elapsed, the occupant tries to get off the vehicle and moves his/her upper body and the webbing 1
4 interferes with the neck or head of the occupant 12 and the movement of the anchor plate 20 is restricted, the impedance of the motor 44 decreases and the current flowing through the resistor 82 increases (FIG. 5, G). At this time, Vc＞Vs ₀ ,
That is, when R ₂ V _S /(R ₁ +R ₂ )>Vs ₀ (2), the input terminal P ₈ becomes H (FIG. 6 H).
When the input terminal _P8 becomes H, the microcomputer 68 changes the output terminal _P3 to L and turns off the motor 44 for a certain period of time _t3 (FIG. 6-1). Then, the output terminal _P3 is set to H again to turn on the motor 44, 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. In addition, input terminal _P8 becomes H when a current higher than a certain value than the motor normal current value, which takes into account the ambient temperature, etc., flows through the motor 44, so even if conditions such as the ambient temperature change, the motor remains stable. Can detect overload.

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 work area and output of the RAM of the microcomputer 68 (outputs "L" to output terminals _P3 to _P7 , _P10 and outputs H to output terminal _P9 ) are initialized (step 100). Wait for input terminal P ₁ or input terminal P ₂ to become L (step 101,
103). When we read that input terminal _P2 has become L,
The output terminal _P3 is set to H to cause the motor 44 to rotate forward, and the output terminal _P6 is set to H to turn on the indicator lamp 98 (step 104). 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 and motor 4 is turned on.
4 and turn on the indicator light 99 (step
102). When the process of step 102 or step 104 is completed, the output terminal _P10 is set to H to discharge the charge of the capacitor C and make it ready for charging (step
105). Next, the value of _t0 is set to _t1 (step 106), and the soft timer subroutine shown in FIG. 8 is processed (step 107). That is, as shown in FIG.
Decrement the value of t ₀ (step 200) and
The process repeats and returns until the value of _t0 becomes zero (step 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. Then output terminal P ₉
is set to L to start charging the capacitor C (step 108), and then the value of _t0 is set to _t2 (step 108).
109), it processes the subroutine shown in FIG. 8 and waits for a predetermined time _t2 to elapse (step 110). Next, the output terminal _P9 is set to H to hold the charge charged in the capacitor C (step 111). This results in
The output voltage Vs ₀ of the voltage amplification circuit 86 corresponding to the motor normal current value is supplied to the − input terminal of the comparator 88 and is used as the reference voltage of the comparator 88 . Next, it is read whether the input terminal _P8 is set to H, that is, whether the movement of the anchor plate step 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 ₃ (step 118), the subroutine shown in FIG.
120). Next, the sound emitted from the speaker 97 is turned off (step 122), and then the stop flag is set to 1 (step 300). The process then returns to step 124. If input terminal _P8 is L in step 112, input terminal
When P ₁ is L, output terminal P ₃ is set to H and motor 44
(steps 124, 126), and when the input terminal _P2 is L, the output terminal _P4 is set to H and the motor 44
(steps 128, 130). Next, it is determined whether the stop flag is set to 1 (step 301), and if it is set to 1, the value of _t0 is set to _t1 (step 302), and the soft timer subroutine shown in FIG. 8 is processed. (Step 303). Then, the process returns to step 118. Also, if 1 is not set, proceed to step 112 without performing the above process.
Return to Note that output terminals P ₃ to _{P 7} , output terminals P ₉ , P ₁₀
The output of is now self-maintaining, so
When the output terminal is at H, there is no change in the output even if the output terminal is further set to H. The same applies to the case of L. Input terminal P ₁ and input terminal P ₂ are both H
If so, return to the first step 100 and turn off the motor 44, indicator light 98, and indicator light 99.
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 vehicle window drive device.

[Effect of the invention] In the seatbelt device control circuit according to the invention,
If the current value flowing through the motor is higher than the normal current after a certain period of time after starting the motor, the motor is turned off for a certain period of time and the movement of the webbing tip is stopped. Even if the webbing interferes with the occupant's neck or head when the occupant moves his or her upper body while the webbing is moving, the occupant will not feel uncomfortable or the motor will not be burnt out. In addition, the normal current value is the value of the current flowing through the motor after a certain period of time has elapsed since the motor was started, so even if conditions such as temperature change, the normal current will change accordingly, and the motor will This has the excellent effect of being able to reliably detect mechanical restraint of rotation.

[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 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. 9 is a problem with the conventional example. FIG. 2 is a side view corresponding to 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...
...Comparator.

Claims (1)

[Scope of utility model registration request] It is 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 includes a motor current detection means that detects the current flowing in the motor that moves the webbing tip, and a motor current detection means that detects the current flowing in the motor that moves the webbing tip, and a motor current detection means that detects the current flowing in the motor that moves the webbing tip. a normal current value holding means for holding a current value detected after a certain period of time has elapsed as a normal current value; A seat belt device control circuit comprising: a motor temporary stop means for turning off the motor for a time.