JPH0349772B2 - - 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 one shown in FIGS. 1 and 2, for example (Japanese Patent Laid-Open 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. Since the belt was designed to be loosened by only a few degrees, if there is any slack when the belt is worn, the amount of slack will increase further. There was a second problem.

Regarding the first problem, a seatbelt retractor has been proposed in which the belt is not retracted using a retraction spring, but is retracted and even pulled out using only a motor (Japanese Patent Application No. 57-27597). (Refer to Japanese Unexamined Patent Publication No. 145545/1983)), which has already been solved. However, even with a seatbelt retractor that retracts using only this motor,
With the buckle switch turned on, the excess seat belt is wound up and tightened, and then a predetermined amount of slack is given, so if there is any slack during the tightening process, the slack amount will be reduced by the predetermined amount. However, the second problem could not be satisfactorily solved.

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 considered to be the cause, and it is thought that such a situation often occurs immediately after seating.

The present invention has been made from this point of view and by focusing on both the above-mentioned cause and the second problem. and a motor that rotates the seat belt in the pull-out direction, a displacement detection device that generates a signal corresponding to the rotation of the winding shaft and detects the displacement of the seat belt in the wind-up direction and the pull-out direction, and a displacement detector that detects displacement of the seat belt in the wind-up direction and pull-out direction, 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 applies a predetermined slack after winding up and tightening the excess belt after the seat belt is worn in the forward and reverse directions; By providing means for reactivating the slack control device after sensing belt withdrawal after the device has finished operating, the belt slack can be adjusted in two stages by a series of operations of tightening and loosening after the belt is installed. The purpose of this study is to solve the above-mentioned problems.

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.
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.
In the figure, 24 is a CPU of the microcomputer 24, which has an output port and an input port, and is equipped with a ROM 25 for storing programs and constant data, and a RAM 26 for temporarily storing 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. . Reference numeral 28 is an input port for inputting a signal from the vehicle speed pulse generator 5 for setting a value for imparting appropriate slack to the belt, and 29 is an input port for engaging a tongue sewn to the belt pull-out end with a buckle. an input port for inputting a signal from a wearing detection device 52 that generates a switch signal that is "ON" when the seat belt is engaged (seat belt fastened state) and "OFF" when the seat belt is disengaged (seat belt not fastened state); Reference numerals 31 and 32 are input ports into which signals from the displacement detection device 23, which detects the rotation angle of the retractor winding shaft 12, are respectively input.

In addition _, as shown in the detailed diagram _of FIG.
It has the function of counting and detecting the rotation direction (winding or drawing direction) and rotation angle of the retractor's winding shaft 12, as well as detecting the relative position of the seat belt. (Incidentally, the displacement detection device can also use a variable resistance that is linked to the movement of the seat belt.) Next, the CPU 24 of the microcomputer incorporates a comparison device, a slack control device, and a means for reactivating the slack control device. The operation will be explained in more detail according to 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 "vehicle speed sensitive slack adjustment", 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 ₁ and S ₂ 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. After that, the vehicle speed is By reversing the motor, the appropriate amount of slack is given to the belt according to the timer Ts.
It sets the . The next step, "drawer," checks signals S ₁ and S ₂ to detect whether or not the belt is being pulled out. Specifically, this drawer is manually operated by the passenger in order to tighten the belt to the body after adjusting the belt slack. If the belt is pulled out or the belt is bent forward, proceed to "Re-adjust the belt slack"; if the belt is not pulled out, proceed to "Ts > 10 seconds". That is, the timer is set to 10 seconds in this embodiment,
The timer Ts in the RAM 26 is checked when "Ts > 10 seconds", and if there is no drawer within a certain period of time after adjusting the belt slack immediately after the seat is seated, the process proceeds to "re-adjusting the belt slack" after this time has elapsed. .

Therefore, the belt slack adjustment is performed again when the belt is pulled out after the first belt slack adjustment and after the timer setting time has elapsed. Also, "re-belt slack adjustment" is "belt slack adjustment"
The motor 18 rotates normally from the output port via the transistor bridge 27, and the signals S ₁ and S ₂ from the input ports 30 and 31 are detected, and the position where the belt is tightened to the tension state is determined 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.

Then, in the next "vehicle speed sensitive slack amount adjustment", processing such as slack adjustment according to the subsequent vehicle speed is performed.
Return to "Batchle SW OFF→ON" and repeat this routine. Regarding "withdrawal", it is also possible to limit the amount of withdrawal that reacts so that it does not react with minute body movements, and to react only when the belt is withdrawn over a certain level. The timer processing of `` is generally performed as a periodic interrupt process as shown in FIG.

As described above, according to this embodiment, even when the seat belt is not in the best position and the seat belt has already been tightened, the slack control device is reactivated, so the seat belt remains in close contact with the occupant and the seat belt function is improved. can be reliably demonstrated.

FIG. 8 shows a second invention, in which the degree of adhesion of the seat belt is improved compared to that shown in FIG. 7. That is, the process up to ~ is the same as that shown in Fig. 7, and the belt is tightened after being attached, and the end position is set to the close contact position N ₁
shall be. After that, the end position of the tightening performed by "drawing out" or "re-belt slack adjustment" after the time set by the timer Ts has elapsed is defined as the close contact position _N2 . Then, at "N ₂ - N ₁ ", compare the previous close contact position N ₁ and the current close contact position N ₂ , and if N ₂ - _{N 1} ≧0, proceed to ``N←N ₁ ''. The value of ₁ is set as the true contact position N, and if N ₂ −N ₁ <0, proceed to “N←N ₂ ” and the value of N ₂ is set as the true contact position N.

In other words, if the length of the belt pulled out from the retractor at the close contact position is smaller between the belt slack adjustment and the re-belt slack adjustment, or if both values match, that value is determined as the more accurate close contact position, and this value is determined. This is the true contact position N, and this N is used as a reference value when applying appropriate slack thereafter.

Therefore, in the "vehicle speed sensitive slack adjustment", the belt slack adjustment is performed according to the vehicle speed based on the true contact position N, and this adjustment is performed in the seventh step.
This is more appropriate than the one shown in the figure.

As described above, according to the present invention, after the occupant is seated and fastens the seat belt, the slack control device
The belt slack is adjusted by a series of operations of tightening and loosening, and after a predetermined period of time has elapsed for the occupant to settle down, or when the belt is pulled out to correct the occupant's seating posture, The means for reactivating the slack control device re-adjusts the belt slack through a series of operations of tightening and adding slack, so excess slack is always removed and the slack is added reliably and appropriately, ensuring that the belt is always worn. It is possible to obtain an optimal belt wearing condition with less discomfort. Moreover, since belt slack adjustment is performed in two stages as described above, the optimum slack is provided depending on the posture of the occupant at the time, and safety can also be improved. In addition, in the second invention, since the close contact position that becomes the reference value when adjusting the belt slack is automatically selected as the one with a high degree of belt tightness, if the belt slack adjustment is not desirable, the first The belt slack can be adjusted based on a better contact position when adjusting the belt slack, and the wearing feeling and safety can be further improved.

[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 seatbelt retractor according to the present invention, FIG. 4 is a side view thereof, and FIG. 5 is an embodiment of the slack control device etc. using the microcomputer of the present invention. , FIG. 6 is a detailed configuration diagram of the displacement detection device, and FIG. 7A is a flowchart showing an embodiment of the control program of the present invention.
Figure 7B is a detailed view of a part of Figure 7A, and Figure 8 is a detailed view of Figure 2.
FIG. 9 is a flowchart showing an example of timer processing using a scheduled interrupt. 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, 52...
...Attachment detection device.

Claims (1)

[Scope of Claims] 1. A take-up shaft to which a seat belt end is fixed; a motor that rotates the take-up shaft in a winding direction and a pull-out direction; , a displacement detection device that detects displacement of the seat belt in the winding direction and the pull-out direction; a comparison device that compares a value set corresponding to a predetermined belt slack amount with an output signal of the displacement detection device; A wearing detection device detects whether a seatbelt is worn; and based on the outputs of this wearing detection device and the comparison device, the motor is rotated in forward and reverse directions, and after the seatbelt is fastened, winding and tightening is performed to wind up the excess belt. a slack control device that later applies a predetermined amount of slack; and a slack control device that restarts the slack control device after a predetermined time has elapsed from the end of the operation of the slack control device, or after detecting belt withdrawal after the end of the operation of the slack control device. A seatbelt retractor comprising: means for activating the seatbelt. 2. A take-up shaft to which the seat belt end is fixed; a motor that rotates the take-up shaft in the winding direction and the unwinding direction; a displacement detection device that detects displacement in the direction and the pull-out 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; and a comparison device that detects the wearing of the seat belt. The motor is rotated in the forward and reverse directions based on the outputs of the attachment detection device and the comparison device, and after the seat belt is attached, the excess belt is wound and tightened, and then a predetermined slack is provided. means for reactivating the slack control device after a predetermined period of time has elapsed since the end of the operation of the slack control device, or after detecting belt withdrawal after the end of the operation of the slack control device; means for comparing the seat belt position when the seat belt is tightened and the seat belt position after the slack control device is reactivated, and setting the minimum value as the best seat belt position; seat belt retractor.