JPH0323386B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a seatbelt retractor, and particularly to a seatbelt retractor that uses a motor to take up and rewind a seatbelt.

Conventionally, as a seatbelt retractor using a motor, there is, for example, one shown in FIGS. 1 and 2 (Japanese Patent Publication No. 52-9891).

This seatbelt retractor rotates a motor 3 using a buckle engagement switch 2 when the seatbelt 1 is pulled out and put on.
The fan-shaped gear 5 further rotates the retractor 8 in the belt loosening direction via the lever 6 and the ratchet wheel 7, and after the belt is let out a certain length, the tension lock state is maintained by the engagement of the lever 6 and the ratchet wheel 7. It is made to be.

However, in such conventional seatbelt retractors, the belt is retracted using a retraction spring in the retractor 8, so the provision of the retraction spring and motor drive complicates the retractor. The first problem is that the belt becomes large and the amount of slack in the belt is set by controlling the rotation of the motor using the buckle switch 2 and limit switches 9, 10, etc. The second problem was that if the belt was loosened when the belt was worn, the amount of slack would be further increased, making it impossible for the seatbelt to perform its original function.

Regarding the first problem, a seatbelt retractor has been proposed in which the belt is retracted and even pulled out using only a motor, without using a retraction spring (Japanese Patent Application No. 57-27597).
issue), has already been resolved. However, even with this seatbelt retractor that uses only the motor to retract, the excess seatbelt is retracted and tightened with the buckle switch turned on, and then a predetermined amount of slack is added. Therefore, if there is slack during the tightening, the amount of slack will significantly exceed the predetermined amount.
For this reason, the second problem of the seatbelt being unable to perform its original function has not been satisfactorily resolved.

The second problem occurs when the seat belt is not in the best position when winding up and tightening the extra seat belt, or when the seat belt gets caught on the arm, or when the seat belt distorts the body. This is the cause, and this type of situation often occurs before the vehicle speed reaches a certain level immediately after seating, and therefore, if the vehicle speed exceeds a certain level, this also occurs due to the passage of time after seating. This is considered to be the best sitting posture for the seat.

In addition, seat belts are designed to protect occupants from accidents that occur while driving, so it is a safety measure to adjust them based on the sitting posture during normal driving. Most preferred.

The present invention has been made from this point of view and by focusing on both the above-mentioned cause and the second problem. Alternatively, a motor that rotates in the pull-out direction, a displacement detection device that emits a signal according to the rotation of the winding shaft and detects displacement of the seat belt in the wind-up direction and the pull-out direction, and a comparison device that compares a value set by the displacement detection device with an output signal of the displacement detection device; a wearing detection device that detects a seatbelt device; A slack control device that tightens the excess belt by winding it in the forward and reverse directions after the seat belt is worn, and provides a predetermined slack after the tightening, and a vehicle speed sensor that detects the vehicle speed and issues a signal after a predetermined time elapses. A tongue is engaged with a buckle by providing a seatbelt retractor having means for reactivating the slack control device when it is detected that the vehicle speed is higher than a predetermined value based on a signal from the vehicle speed sensor after the slack control device is activated. Immediately after this, the belt that has been pulled out in excess is first wound and tightened, and after the belt is tightened, a predetermined amount of slack is added (hereinafter, both consecutive operations are referred to as belt slack adjustment), and then the belt is tightened under the set conditions. The purpose of this invention is to solve the above-mentioned problem by adjusting the belt slack again.

The present invention will be explained below based on the drawings. Third,
FIG. 4 shows an embodiment of the present invention. In the figure, 11 is a housing formed in a substantially U-shape, 12 is rotatably supported by side plates 11a and 11b of this housing, and one end of the belt 1 is This is a fixed winding shaft.

One end of this winding shaft 12 is provided with a winding shaft 1 in case of an emergency.
A known emergency locking mechanism 13 is provided to prevent rotation of the drawer 2 in the withdrawal direction.

A rotation angle detection ratchet wheel 14 is fixed to the protrusion at the other end of the take-up shaft 12, and a worm wheel 16 is loosely fitted around a friction transmission spring 15 so as to be freely rotatable. A snap spring 17 is engaged with the end of the winding shaft 12, and a worm wheel 16 is engaged with the end of the winding shaft 12.
It is prevented from coming off.

18 is a motor fixed to the upper part of the housing 11, and the rotation shaft 18a of this motor 18 is connected to the side plate 11a.
It protrudes further rearward, and a worm 19 is fixed thereto. This worm 19 is meshed with a worm wheel 21 fixed to a shaft 20 which is disposed perpendicularly to the worm 19 on the side plate 11a and is rotatably supported. Furthermore, a worm 22 that meshes with a worm wheel 16 that is loosely fitted onto the winding shaft 12 is fixed to the end of the shaft 20.

Therefore, when the motor 18 is rotated, its rotation is decelerated via the worm 19, the worm wheel 21, and the worm 22, and the rotation is reduced by the worm wheel 16.
is transmitted to. The rotation of the worm wheel 16 is caused by the friction force between the worm wheel 16 and the friction transmission spring 15.
4 to the winding shaft 12.

Reference numeral 23 denotes a displacement detection device using two photocouplers, which is fixed to the side plate 11a of the housing 11 and emits a signal according to the rotation of the winding shaft to detect the displacement of the seat belt in the winding direction and the pulling direction. be.

Next, FIG. 5 shows an embodiment in which a microcomputer is used as a slack control device and the like.
24 in the figure is the CPU of the microcomputer,
It has an output port and an input port, and is connected to a ROM 25 that stores programs and constant data, and a RAM 26 that temporarily stores input signals, calculation results, etc. Further, 27 is a transistor bridge circuit for controlling the motor 18 in forward and reverse directions, and is controlled so that by rotating the motor 18 in the normal direction, the belt is wound up, and by rotating the motor 18 in the reverse direction, it is controlled to provide appropriate slack. . 51 is a vehicle speed sensor which emits a pulse signal for setting a value for giving appropriate slack to the belt, and is connected to input port 2.
It continues to 8. 29 is a switch signal which is "ON" when the tongue sewn on the belt drawer end is engaged with the buckle (seatbelt wearing state) and OFF when it is not engaged (seatbelt not wearing state). Input ports 31 and 32 input the generated signal from the mounting detection device 52, and input ports 31 and 32 input the signal from the photocoupler 23, which detects the rotation angle of the retractor winding shaft 12.

As shown in the detailed diagram of FIG. 6, the displacement detection device 23 receives pulse signals from two photocouplers.
It has a function of counting S ₁ and S ₂ by the CPU 24 of the microcomputer, detecting the rotation direction (winding or pulling direction) and rotation angle of the retractor's winding shaft 12, and detecting the relative position of the seat belt.

Next, the operation of the CPU 24 of the microcomputer incorporating the comparison device, slack control device, and means for reactivating the slack control device will be further explained in accordance with the flowchart shown in FIG.

When the occupant is seated and the tongue sewn to the belt drawer end engages with the buckle, and a signal is input from the input port 29, the "buckle SW" changes from OFF to ON, and the "belt In other cases, proceed to ``Setting the appropriate amount of slack'', which will be described later. As shown in Figure 7B, this "belt slack adjustment" involves two steps: "wrapping" the extra belt that has been pulled out after the belt is worn, and tightening the belt tightly to the body, and stopping the belt tightening at a predetermined tightening position. It consists of "belt stopping" and "belt slackening" which loosens the belt by a predetermined length, and the belt slackness is adjusted immediately after seating. That is, the motor 18 is rotated forward from the output port via the transistor bridge 27, the signals S <sub>1</sub> and S <sub>2</sub> of the input ports 30 and 31 are detected, and the position where the belt is tightened to the tension state is defined as the belt tight position N, and then the belt is tightened to a predetermined position. By reversing the motor, the appropriate amount of slack is given to the belt, and the process proceeds to ``Current vehicle speed?''.

This "Current vehicle speed?" detects the vehicle speed when the seatbelt is fastened, and if it is above a certain value (10 km/h in this example), the "timer"
If the speed is less than this, proceed to "Vehicle speed >10km/h". Note that the vehicle speed here is detected by counting the vehicle speed pulse signal from the input port 28 every unit time.

In addition, when "vehicle speed > 10 km/h", the vehicle speed is detected by the vehicle speed sensor and the vehicle speed exceeds a certain value (10km/h).
Km/h or more), proceed to "Re-adjust belt slack". The "timer" is a process when the vehicle speed is already above the certain value when the belt is installed,
The count is performed in the microcomputer 24, and when a certain period of time (for example, 10 seconds) is exceeded, the process proceeds to "re-belt slack adjustment".

Therefore, belt slack adjustment is performed again after the timer setting time has elapsed after the first belt slack adjustment, or when the vehicle speed exceeds a certain value.

This "re-belt slack adjustment" operates in the same manner as the "belt slack adjustment" described above, and causes the motor 18 to rotate forward from the output port via the transistor bridge 27, and the signals S ₁ and S ₂ of the input ports 30 and 31 to be The position where the belt is sensed and tightened to the tension state is defined as the belt tight position N, and then the belt is given an appropriate amount of slack depending on the vehicle speed by reversing the motor.

In the next "belt position N setting",
The belt contact positions N for both "belt slack adjustment" and "re-belt slack adjustment" are compared, and the minimum value is set as the belt position N. Then, in "setting the appropriate amount of slack", based on this belt position N, the appropriate amount of belt slack is adjusted according to the subsequent vehicle speed, and the process returns to "buckle SW OFF → ON" and the process is repeated. It is.

As described above, according to this embodiment, when the vehicle speed exceeds a predetermined value, the seatbelt is re-tightened, so that the seatbelt comes into close contact with the occupant, and the seatbelt can reliably perform its function.

FIG. 8 shows another embodiment of the present invention, which is particularly to be used in a seat belt retractor installed in a driver's seat. That is, since the driver's driving position is unstable due to gear changes and the like during acceleration, the driver attempts to adjust the belt slack again in a steady driving state when the driving position becomes stable.

In the figure, "buckle SW OFF→ON" and "belt slack adjustment" are the same as those shown in FIG. 7.

"Current vehicle speed" detects the current vehicle speed, and if the vehicle is stopped or driving at low speed, the driver is often not in the correct driving position, so if the vehicle speed is below a certain speed (for example, 10 km/h), If so, wait until the vehicle speed exceeds the certain value and proceed to "Acceleration". For this "acceleration", changes in vehicle speed per unit time are detected as acceleration, and if the acceleration is above a certain level, the system waits as is, and when it is below a certain level (during steady driving), the system starts "re-belt slack adjustment". move on. Therefore, during the "re-belt slack adjustment", since the vehicle is in a steady running state, the sitting posture can be determined to be the best position, and the above-mentioned belt slack adjustment will be performed in this best position. Both "belt position N setting" and "appropriate slack amount setting" are the same as in the above embodiment,
"Belt slack adjustment" and "Re-belt slack adjustment"
The two belt contact positions N are compared, and the minimum value is set as the belt position N. Based on this belt position N, processing such as adjusting the appropriate amount of belt slack according to the subsequent vehicle speed is performed, and the "buckle SW OFF → "ON" and repeat the subsequent processing.

As explained above, the present invention includes a take-up shaft to which the end portion of the seat belt is fixed, a motor that rotates the take-up shaft in the winding direction or the pull-out direction, and a signal corresponding to the rotation of the take-up shaft. a displacement detection device that detects displacement of the seatbelt in the winding direction and the withdrawal direction; a comparison device that compares the output signal of the displacement detection device with a value set corresponding to a predetermined amount of belt slack; a wearing detection device for detecting the wearing of a seatbelt; a tightening operation for winding an excess belt after the seatbelt is fastened by rotating the motor in forward and reverse directions based on the outputs of the wearing detection device and the comparison device; a slack control device that applies a predetermined slack; a vehicle speed sensor that detects vehicle speed and issues a signal; and a vehicle speed sensor that detects vehicle speed and issues a signal; and when the slack control device detects that the vehicle speed is higher than a predetermined value based on a signal from the vehicle speed sensor after activation, the slack control device is reactivated. Firstly, it is possible to control the belt to an appropriate slack position that matches the sitting posture in the traveling state in order to adjust the belt slack in the traveling state, and secondly, it is possible to control the belt to an appropriate slack position that matches the seating posture in the traveling state. After the adjustment, the belt slack adjustment is performed again when the occupant's posture is correct, so by adjusting the belt slack again, a more optimal belt wearing condition can be obtained, improving the feeling of wearing and safety. be able to. Furthermore, in the embodiment shown in Fig. 8, the belt slack is adjusted again during steady running conditions without adjusting the belt slack during acceleration, so the purpose is to prevent and reduce injury to the occupants in the event of an accident during driving. The seat belt used as a seat belt can be adjusted based on the posture during driving, and the slack can be adjusted to be optimal for safety. In addition, when belt tightening is performed during driving operations such as gear changes, it is conceivable that this will interfere with the operation, but in the embodiment shown in Fig. 8, it will not interfere with driving operations. This makes it possible to put the seatbelt in the optimal state.

[Brief explanation of the drawing]

FIG. 1 is an electric circuit diagram showing an example of a conventional seat belt retractor, and FIG. 2 is a schematic configuration diagram thereof.
FIG. 3 is a front view showing an embodiment of the configuration of a seatbelt retractor according to the present invention, FIG. 4 is a side view thereof, and FIG. 5 is an implementation of the slack control device etc. using the microcomputer of the present invention. 6 is a detailed configuration diagram of the displacement detection device, FIG. 7A is a flowchart showing an embodiment of the control program of the present invention, FIG. 7B is a partial detailed diagram of FIG. 7A, FIG. 8 is a flowchart showing another embodiment of the control program of the present invention. 1...Seat belt, 11...Housing, 1
2... Winding shaft, 14... Rotation angle detection ratchet wheel, 18
... Motor, 23 ... Displacement detection device, 24 ... Microcomputer, 25 ... ROM, 26 ...
RAM, 27...transistor bridge.

Claims (1)

[Claims] 1. A take-up shaft to which the seat belt end is fixed, a motor that rotates the take-up shaft in the winding direction or the pull-out direction, and a signal that emits a signal according to the rotation of the take-up shaft to rotate the seat belt in the winding direction. a displacement detection device that detects displacement in the pull-out direction; a comparison device that compares an output signal of the displacement detection device with a value set corresponding to a predetermined amount of belt slack; and a comparison device that detects whether the seat belt is fastened. A wearing detection device, and the motor is rotated in forward and reverse directions based on the outputs of the wearing detection device and the comparison device to perform winding tightening to wind up an excess belt after the seat belt is fastened, and to provide a predetermined slack after the winding tightening. The vehicle includes a slack control device, a vehicle speed sensor that detects vehicle speed and issues a signal, and means for reactivating the slack control device when it is detected that the vehicle speed exceeds a predetermined value based on a signal from the vehicle speed sensor after the slack control device is activated. A seat belt retractor characterized by: