JPH0349771B2 - - 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 seat belt retractors, the belt is retracted by a retracting spring in the retractor 8, so frequent pulling out and retraction of the belt causes the retracting There is an inconvenience that the winding force of the spring decreases, making it impossible to wind all of the pulled out belt into the winder 8, and a part of the belt remains pulled out.

The present applicant has already proposed a seatbelt retractor that does not use such an inconvenient retractable spring and uses a motor to retract and unwind the retractable spring. No inconvenience occurs due to a decrease in force (see Japanese Patent Application No. 57-27597 (see Japanese Patent Application Laid-open No. 58-145545)).

However, even with a seatbelt retractor using this motor, if the belt is being wound up by the motor and the rotation of the winding shaft stops for a certain period of time (1 to 2 seconds), this winding is controlled. Since the device that is used for winding the seat belt determines that winding is complete and stops winding, if the seat belt gets caught on the passenger's arm or headrest, and the belt stops midway through winding, the belt will not be able to continue winding any further. There are problems to be solved in that the unwound end of the belt remains unwound inside the retractor, and this remaining belt portion becomes an obstacle to getting on and off, and is also aesthetically undesirable.

The present invention has been made by focusing on both the inconveniences of the seat belt retractor using a winding spring and the problems to be solved with the seat belt retractor using a motor. When the buckle switch is OFF (when the belt is not attached) and the tongue is not engaged with the buckle, if the seatbelt is being wound up and the rotation of the winding shaft in the winding direction stops for a predetermined period of time, the motor This is intended to solve the above-mentioned inconveniences and problems by stopping the drive in the winding direction of the seat belt and re-driving the motor in the winding direction when the seat belt is pulled out again. be.

The present invention will be explained below based on the drawings.

In FIGS. 3 and 4, 11 is a housing formed in a substantially U-shape, and 12 is a side plate 11 of the housing.
a, 11b, and is rotatably supported by the belt 1.
It is a winding shaft to which one end is fixed.

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.

23 is a displacement detection device using two photocouplers, and is fixed to the side plate 11a of the housing 11.

Next, FIG. 5 shows an embodiment using a microcomputer 24 constituting a belt control device. It is provided with means for stopping the drive in the winding direction, and means for re-driving the motor in the winding direction, which corresponds to the step shown in FIG. In the figure, 24 is a CPU of a microcomputer, which 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. Also 27
is a transistor bridge circuit for controlling the motor 18 in the forward and reverse directions; by reversing the motor 18, the belt is wound up, and by rotating the motor 18 in the forward direction, it is controlled to provide appropriate slack. Reference numeral 28 indicates an input port for inputting a signal from a vehicle speed pulse generator 51 for setting a value for giving an appropriate slack to the belt, and 50 indicates a tongue sewn to the end of the belt that is engaged with the buckle. 29 is an input port for inputting this signal; 29 is an input port for inputting this signal; 31; Reference numeral 32 designates input ports into which signals from the displacement detection device 23 for detecting the rotation angle of the retractor winding shaft 12 are respectively input.

As shown in the detailed diagram of FIG. 6, the displacement detection device 23 counts the pulse signals S ₁ and S ₂ from the two photocouplers using a microcomputer.
It has the function of detecting the rotation direction and rotation angle of the retractor as well as the relative position of the seat belt.

Next, a microcomputer as a belt control device including means for stopping the drive of the motor in the winding direction and means for re-driving the motor in the winding direction is used.
The operation of the CPU 24 will be further explained according to the flowchart shown in FIG.

In other words, the tongue is removed from the buckle, and the buckle switch, which is the attachment detection device, is turned off from the ON state.
When the state changes to OFF, the “Batsukuru SW ON→
This routine starts from "OFF" and port 29
When the buckle signal changes from the ON state to the OFF state, the CPU 24 of the microcomputer issues a signal from the output port to the transistor bridge circuit 27 to wind the belt, thereby "belt winding start". This winding causes the rotation angle detection ratchet wheel 14 to rotate, and from this the displacement detection device 23
Detects the rotation angle of the winding shaft 12 and determines whether winding is incomplete or complete. In other words, the determination as to whether or not this winding is complete is made after a certain period of time (“periodic interrupt” described later).
As shown in (2 seconds in this embodiment), it is detected whether or not a winding pulse is generated as the rotation angle detection ratchet wheel 14 rotates, and if it is generated, it means that winding is in progress.
If the result is NO, check again, and if it does not come out,
The winding is "completed" and the answer is "Yes" and the process moves on to "Do you want to start?" In the next "Drawer?", if the above-mentioned "Complete" is an incorrect "Complete" with a remaining part caused by the belt getting caught on an arm, etc. during winding, the passenger concerned By pulling out the belt again, "Drawer?"
The answer is Yes, the process returns to the start of belt winding, and the belt is re-wound. Therefore, "belt winding start" means both the initial belt winding and the re-winding. Of course, “Is winding complete?” is Yes,
If this Yes truly means "Completion" without leaving any remaining part of the winding, then of course the withdrawal will not be performed, so "Withdraw" will be NO, and the process will proceed to "Start Belt Winding" to rewind the belt. is never done. This is the basic routine that forms the main part of the present invention.

Next, the operation of the above-mentioned "Is the winding completed?" will be explained in detail in accordance with the timed interruption shown in FIG.
This flowchart detects the rotation of the retractor's winding shaft and determines whether winding is incomplete or complete.If the winding shaft is rotating, the answer is Yes. "Timer clear"
Proceed to "T ₂ ← 0", clear timer T ₂ for determining unnecessary stoppage of 2 seconds or more, and proceed to "NEXT". On the other hand, the rotation of the winding shaft has stopped.
If “Is the retractor rotating?” is NO, then
If the process goes to "T2>2 seconds" and is longer than 2 seconds, the process goes to "winding F clear", and if it is within 2 seconds, the process passes the "winding clear" process and goes to "NEXT".

On the other hand, if "Is the retractor rotating?" is NO and winding has stopped, the time is checked by the timer, and if the time is 2 seconds or more and T ₂ > 20, "Wind-up F clear"
, previously proceed to "NEXT",
When proceeding to "winding F clear", the winding flag used in the motor drive process shown in FIG. 9 is cleared, and winding is completed.

FIG. 9 shows a process for controlling the motor based on the rotation detection routine shown in FIG. 8. That is, the winding determination flag stored in the RAM 25 is checked, and if the flag is set, the process proceeds to "motor winding drive";
An output is output from the output port to control the motor in the winding direction until the flag is cleared, and the motor continues rotating in the winding direction to continue winding. On the other hand, if "Wind-up F?" is cleared, that is, if winding is completed, "Normal control" is used to perform winding, etc. on the belt drawer.
Target position control is performed by comparing the current position of the belt with the target position, and the interrupt process returns to the main routine at "RTi".

FIG. 10 shows the winding determination process in the main routine. That is, in the "buckle SW?", it is determined whether the buckle switch is ON or OFF based on the signal of the port 29, and when it is in the ON state (belt attached state), the process proceeds to "other processing",
For example, tightening or loosening the belt after putting it on is performed. On the other hand, when in the OFF state (belt not attached),
Compare it with the previous buckle switch signal at "ON → OFF", and if it changes from ON to OFF, that is, when the tongue is removed from the buckle, proceed to "winding F set", set the winding flag, and set the winding flag. Winding control is performed using the motor drive routine shown in FIG. On the other hand, if the belt gets caught on an arm or the like during winding and is in the OFF state from the front, proceed to "Belt Pullout", and in this case, check whether the belt has been pulled out (by comparing the belt position with the previous time). If it is pulled out, proceed to "winding F set".

Therefore, the "winding F set" includes the first
When the tongue is removed from the buckle, and when the belt is pulled out, the winding and rewinding are performed in a routine that sets the winding flag and drives the motor shown in Figure 9. It will be done. Of course, if "belt drawer" is "none", then without setting the winding flag, perform other processing in the main routine in the "other processing" mentioned above and return to "buckle SW?" becomes.

The above processing and judgment are repeated within the microcomputer.

As explained above, the present invention includes a winding shaft to which a seat belt end is fixed, a motor that rotates the winding shaft in the belt winding direction or the belt pulling direction,
a displacement detection device that detects the displacement of the seat belt in the winding direction and the rotation angle in the pull-out direction by emitting a signal according to the rotation angle of the take-up shaft; a wearing detection device that detects the wearing of the seat belt; The belt control device includes a detection device and a belt control device that drives a motor based on the output of the displacement detection device. The present invention includes a means for stopping the driving of the motor in the retracting direction, and a means for re-driving the motor in the retracting direction when the seatbelt is pulled out again after the seatbelt has been removed. When leaving the
When the seatbelt is retracted after the tongue is removed from the buckle, if the seatbelt gets caught on an arm or head rest and the retractor shaft does not rotate in the rewinding direction for a predetermined period of time, there is no means to stop the motor. It is possible to protect the device by stopping the drive of the motor in the retracting direction as if retracting is completed, and even if the seat belt remains outside the retractor, the seat belt can be easily pulled out again. The means for re-driving the motor can re-drive the motor in the winding direction to re-wind the seat belt, thereby completely storing the belt inside the retractor without leaving any belt remaining outside the retractor. This solves both the disadvantages of the retractor using a retracting spring and the problems of the retractor using a motor as described above.

[Brief explanation of drawings]

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 the seat belt retractor according to the present invention, FIG. 4 is a side view thereof, and FIG. 5 is a schematic configuration diagram of an embodiment using the microcomputer of the present invention. FIG. 6 is a detailed configuration diagram of the displacement detection device, FIG. 7 is a flowchart showing an overview of the present invention, FIG. 8A is a flowchart for determining the completion of winding, and FIG. Detailed view of the part, Figure 9 is a flowchart for controlling the motor,
FIG. 10 is a flowchart showing the winding determination process. 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 having a fixed end portion of the seat belt, a motor for rotating the take-up shaft in the belt winding direction and the belt pulling-out direction; a displacement detection device that emits a signal and detects the displacement in the retracting direction and the displacement in the pull-out direction of the seat belt; a wearing detection device that detects whether the seat belt is worn or not; the wearing detection device and the displacement detection device; a belt control device that drives the motor based on an output signal from the detection device; and the belt control device detects the completion of winding of the seat belt based on the presence or absence of displacement of the belt for a predetermined period of time or more, and controls the winding of the motor. A seatbelt retractor comprising: means for stopping driving in the retracting direction; and means for re-driving the motor in the retracting direction when the seatbelt is pulled out again after the seatbelt has been removed.