JP3602369B2 - Seat belt retractor - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an automatic winding device for a vehicle seat belt.
[0002]
[Prior art]
Automatic winding of a seatbelt for protecting an occupant seated in a vehicle seat from a collision accident is usually performed using a long spring. In a winding device that winds a seat belt with a single spring, the seat belt wound by the elasticity of the spring may strongly press the chest of the seated occupant, giving the occupant an uncomfortable feeling of pressure. . Therefore, there is known a seat belt retractor that uses two types of mainsprings having different spring outputs to reduce the seat belt retracting force when the occupant wears the seat belt, thereby reducing the occupant's feeling of pressure. (JP-B-60-30576, etc.).
[0003]
The above-mentioned two types of springs are a large spring having a large spring force and dedicated to seat belt winding, and a small spring having a small spring force acting only when the occupant wears the seat belt. The two types of springs, large and small, are automatically switched and used by a switching mechanism separately provided. That is, when the occupant wears the seat belt, the occupant is switched to the small spring, the seat belt restrains the occupant with the weak spring force of the small spring, and the occupant receives a small feeling of pressure at this time. Even when moving in a forward bending posture or the like, the small mainspring expands and contracts the seat belt in accordance with the movement of the occupant with a weak spring force, so that the movement of the occupant becomes easy. When the occupant removes the seat belt, the seat belt is switched to the mainspring, and the seat belt is wound up at high speed by the strong spring force of the mainspring.
[0004]
[Problems to be solved by the invention]
The mainspring used in the seat belt retractor as described above requires a high unit price in order to secure the necessary rigidity and spring properties. Is expensive and currently limited to high-end car specifications.
[0005]
Further, the seat belt is forcibly wound by a mainspring. However, poor winding may occur depending on the state of the seat belt before winding, and the winding is not reliable. Furthermore, when the seat belt is wound up at a good speed with the large spring, the large spring expands at a high speed and collides with the inner surface of the case accommodating the spring, and the collision sound at this time becomes an unpleasant sound. There is a defect.
[0006]
SUMMARY OF THE INVENTION It is an object of the present invention to provide a seat belt retractor that eliminates the need for a large mainspring having a high spring force and high cost, and that can improve poor winding and a feeling of pressure on an occupant.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, a seat belt winding device according to the present invention includes a rotation driving source provided between a winding shaft of a seat belt and a rotation driving source for urging the winding shaft to rotate in a seat belt winding direction. Applies a rotational force to the winding shaft to wind up the seat belt, and when the torque value at the time of winding exceeds a predetermined value, a slipping operation is performed to stop winding of the seat belt, and the seat belt is pulled. An elastic member is provided that is elastically deformed by the rotational force when the reel is rotated in the seat belt unwinding direction and that rotates the reel in the seat belt rewinding direction by an elastic restoring force when the seat belt is released from tension. The elastic member is constituted by a first torsion coil spring, whereby the rotation of the winding shaft in the seat belt feeding direction in the forward bending operation of the occupant is permitted by the elastic deformation of the first torsion coil spring, The mechanism comprises a clutch input member driven by a rotary drive source, a clutch output member connected to the elastic member, and a clutch spring interposed between the two members, and the clutch spring comprises a second torsion coil spring. In addition, one end of the second torsion coil spring is attached to a clutch output member, and the coil portion of the second torsion coil spring is fitted to the outer periphery of the clutch input member with a predetermined frictional force. It is characterized by the following.
[0008]
Here, as the rotary drive source, an electric motor described later is desirable in terms of function and compactness, but may be a hydraulic drive source or the like. In addition, the clutch mechanism has a one-way clutch structure that transmits the rotational force of the rotational drive source in a certain direction directly to the seat belt winding shaft. If the torque at the time of winding the seat belt increases to a predetermined value, the clutch slips and the clutch is turned off. And idle.
[0009]
The elastic member can be composed of, for example, a first torsion coil spring or a mainspring spring. These elastic deformations allow the occupant to rotate the winding shaft in the seat belt feeding direction in the forward bending operation. By appropriately setting the number of turns, the axial dimension, and the radial dimension of the first torsion coil spring and the mainspring spring, the permissible number of rotations or the amount of rotation of the winding shaft can be set to a desired value.
[0010]
The structure of the clutch mechanism is arbitrary as long as the above function can be realized. For example, a clutch input member driven by a rotary drive source, a clutch output member connected to the first torsion coil spring, and an interposition between the two members are provided. A second torsion coil spring, one end of the second torsion coil spring is attached to the clutch output member, and the coil portion of the second torsion coil spring is connected to the outer periphery of the clutch input member. Can be fitted with a predetermined frictional force. The frictional force between the clutch spring and the clutch input member is made to correspond to the idling start torque value of the clutch mechanism.
[0011]
When the winding shaft is rotated between the winding shaft and the clutch mechanism in the direction in which the seat belt is extended, the winding shaft is rotated by one rotation. Mechanically engage with each other, but allow the clutch mechanism to idle due to the reverse rotational force of the winding shaft until the mechanical engagement. A pair of stopper members may be arranged.
[0012]
The pair of stopper members are arranged one by one on the winding shaft side and one on the clutch mechanism side. When the one on the winding shaft side rotates with the winding shaft and engages with the one on the clutch mechanism side by one rotation, the clutch It serves to release the torsion coil spring from excessive tightening by idling the mechanism.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. 1 to 7, a second embodiment will be described with reference to FIG. 8A, and a third embodiment will be described with reference to FIG.
[0014]
FIG. 1 is a longitudinal sectional view of the seat belt retractor, and FIG. 2 is a right side view thereof. This winding device winds a seat belt 1 indicated by a chain line in FIG. 2 around a reel 2. The winding shaft 3 penetrates the center of the reel 2 and is fixed to the reel 2. A rotary drive source 4 for rotating only in the direction; a clutch mechanism 5 and a first torsion coil spring 6 disposed between the rotary drive source 4 and the winding shaft 3.
[0015]
The winding shaft 3 is rotatably supported by a housing 7, and the housing 7 is fixed to a part of the vehicle body with bolts or the like. The rear end of the winding shaft 3 protruding from the housing 7 is connected to an external lock mechanism 8. The lock mechanism 8 is permanently installed in the seat belt device of the vehicle, and fixes the reel 3 at the time of a vehicle collision. A first torsion coil spring 6 is fitted around the outer periphery of a substantially cylindrical connection block 11 coaxially fixed to the end of the winding shaft 3, and the connection block 11 is connected to the clutch mechanism 5 via the first torsion coil spring 6. Linked to
[0016]
The rotation drive source 4 rotates the winding shaft 3 only in the seat belt winding direction (counterclockwise direction in FIG. 2), and in the embodiment shown in FIG. A rotation drive shaft 34 is shown, which is decelerated and rotated by a connected pinion gear 32 via a speed reduction mechanism 33, but is not limited to this. The rotary drive shaft 34 is disposed coaxially near the tip of the winding shaft 3, and the cylindrical clutch input member 21 is coaxially fixed to an end of the rotary drive shaft 34 on the side of the winding shaft 3. The tip of the clutch input member 21 is rotatably inserted into the front surface of the connection block 11, and the rotation drive shaft 34, the clutch input member 21, the connection block 11, and the winding shaft 3 are coaxially held.
[0017]
A cylindrical clutch output member 22 is externally mounted on the outer periphery of the clutch input member 21 so as to be relatively rotatable. A clutch spring 23 for switching between rotation and idling is interposed between the clutch input member 21 and the clutch output member 22. The clutch input member 21, the clutch output member 22, and the clutch spring 23 constitute a clutch mechanism 5 that idles when the torque value at the time of belt winding exceeds a predetermined value to cut off power transmission to the reel 3. .
[0018]
FIG. 3 shows a specific example of the connection block 11 in which a disk-shaped flange 13 is integrally protruded from a part of the outer periphery of the column body 12, and is penetrated in a plurality of places of the flange 13 in the thickness direction. A spring stopper hole 14 is formed, and a stopper portion 41 protruding in the axial direction is formed integrally (may be a separate part) on a part of the front surface of the flange 13 in the circumferential direction.
[0019]
As shown in FIG. 4, the first torsion coil spring 6 has a shape in which an arm 6b is projected radially in one end of a coil 6a and an arm 6c is projected axially in the other end. With the axial arm 6c inserted into any one of the spring retaining holes 14 of the connection block 11, the coil 6a is loosely inserted into the outer periphery of the cylindrical body 12. In the drawings, the spring stopper holes 14 are provided at a plurality of positions. However, the spring stop holes 14 are provided so that the torque of the first torsion coil spring 6 can be adjusted. A stop hole 14 may be provided.
[0020]
FIG. 5 shows a specific example of the clutch output member 22. The clutch output member 22 has a spring retaining slit 25 formed in a part of the front end surface of the cylindrical main body 24 in the axial direction, and a spring retaining slit 26 formed in the part of the rear end surface in the axial direction. A stopper portion 42 that protrudes in the axial direction is formed integrally (may be a separate part) in a part of the direction. The cylindrical main body 24 of the clutch output member 22 is rotatably inserted around the outer periphery of the clutch input member 21.
[0021]
The clutch spring 23 is a second torsion coil spring 23 as shown in FIG. 6, in which an arm 23b is projected in one end of the coil 23a in the radial direction, and the other end of the coil 23a is released without the arm. Is at the end. The coil portion 23a is press-fitted into the outer periphery of the clutch input member 21 so as to be slidable in the circumferential direction with a predetermined frictional force, and the cylindrical body 24 of the clutch output member 22 is fitted to the clutch input member 21 so as to surround the coil portion 23a. The arm portion 23b of the clutch spring 23 is inserted into the spring stopper slit 25 on the front surface thereof and locked. Further, the radial arm 6b of the first torsion coil spring 6 is inserted and locked into the spring retaining slit 26 on the rear surface of the cylindrical body 24, and the cylindrical body 24 is placed on the outer periphery of the coil section 6a of the first torsion coil spring 6. It is inserted. At this time, the rear end surface of the cylindrical body 24 and the front surface of the flange 13 of the connection block 11 face each other with a certain annular gap g as shown in FIG. A pair of stopper members 41 and 42 exist at different positions in the gap g, and when one of the stopper members 41 rotates and moves along the gap g, it comes into contact with the other and is driven to rotate. Will be described later.
[0022]
The electric motor 31 for rotating the rotary drive shaft 34 in a fixed direction is, for example, a small and lightweight micromotor, which is activated by a pulse signal input when the seat belt 1 needs to be wound, and starts the seat belt winding operation. The operation is stopped after the elapse of the time determined by the timer 35 indicated by the chain line. The pulse signal for operating the electric motor 31 may be generated by, for example, a switch provided on a buckle mounted on a vehicle seat (not shown). That is, when the occupant inserts and locks the tongue of the seat belt into the buckle to fasten the seat belt, the switch is turned on, a pulse signal is transmitted, and the operation of the electric motor 31 is started. Further, the switch is turned off when the occupant releases the tongue from the buckle to release the seat belt, and the electric motor 31 starts operating even with the pulse signal transmitted at this time.
[0023]
Next, the operation of the device of the present invention will be described in order.
[0024]
When the occupant seated on the seat has finished feeding out the seat belt by a predetermined amount, it is assumed that the pair of stopper members 41 and 42 have, for example, a positional relationship shown in FIG. Here, when the occupant inserts the tongue into the buckle to fasten the seat belt, the electric motor 31 starts operating, the rotation drive shaft 43 rotates in the seat belt winding direction, and the clutch input member 21 rotates in the same direction. . At the beginning of this rotation, the clutch spring 23 rotates integrally with the rotation of the clutch input member 21, the clutch output member 22 locked by this rotates integrally, and further, the clutch output member 22 and the first The connection block 11 and the first torsion coil spring 6 connected by the torsion coil spring 6 also rotate integrally, and the winding shaft 3 rotates in the seat belt winding direction, and winding of the seat belt is started. Since the first torsion coil spring 6 is tightened in any one direction (compression or extension direction) during the above-mentioned winding, the clutch output member 22 and the connection block 11 are applied with a reverse preload that can cancel this. Interposed in between.
[0025]
When the winding is started and the seat belt starts tightening the occupant's chest, the torque at the time of winding the seat belt starts to increase sharply. When the torque value exceeds a predetermined value, the clutch spring 23 moves to the outer periphery of the clutch input member 21. After that, the rotation drive shaft 34 and the clutch input member 21 idle, the rotation of the components from the clutch output member 22 to the winding shaft 3 stops, and the seat belt winding operation ends. Further, the frictional force between the clutch spring 23 and the clutch input member 21 is set so that such a winding operation is performed. After the seat belt winding is completed, the operation of the electric motor 31 is stopped when the timer set time has elapsed. At this time, the relative positional relationship between the pair of stopper members 41 and 42 hardly changes, and they are separated, for example, as shown in FIG.
[0026]
As described above, when the occupant wears the seatbelt, the seatbelt is forcibly wound by the electric motor 31, so that the seatbelt is reliably wound regardless of the state of the seatbelt. Each rotating component transmitting the rotating force rotates without generating a loud noise, so that a quiet seat belt can be wound. Further, it is possible to adjust the seat belt winding speed to an appropriate value by controlling the electric motor 31, and in this way, damage to the components is suppressed and durability is improved.
[0027]
Further, when the occupant wears the seat belt, the pressing force received by the occupant from the seat belt is determined only by the spring force due to the restoring force of the first torsion coil spring 6, and this pressing force is weak and gives the occupant an uncomfortable feeling of pressure. Do not give. Further, when the occupant wearing the seat belt moves largely in a forward bending posture and pulls the seat belt, the first torsion coil spring 6 performs a soft seat belt winding operation.
[0028]
When the occupant pulls the seat belt in a forward bending posture or the like, a rotational force is applied to the reel 2 in the seat belt payout direction, and the reel 3 rotates counterclockwise in FIG. The belt is extended. The reverse rotation of the winding shaft 3 also causes the coupling block 11 to integrally rotate in the reverse direction, but the clutch output member 22 does not rotate and remains stationary because the electric motor 31 is stopped and the rotary drive shaft 34 is in the locked state. As a result, as shown in FIG. 7C, the stopper member 41 of the connection block 11 rotates and moves through the gap g and approaches the stopper member 42 of the clutch output member 22, during which the first torsion coil spring 6 is connected to the connection block. At 11 the spring force increases.
[0029]
When the occupant loses the pulling force applied to the seat belt by, for example, returning to the normal posture from the forward bending posture, the rotational force in the seat belt winding direction is applied to the connection block 11 by the restoring force of the first torsion coil spring 6. Energized, the connection block 11 and the winding shaft 3 rotate, and the seat belt is wound up only by the spring force of the first torsion coil spring 6, and the seat belt is weakened by the first torsion coil spring 6, Therefore, the chest of the occupant is always restrained by the soft touch, and a feeling of oppression is not given. FIG. 7D shows the positional relationship between the stopper members 41 and 42 when the seat belt is wound again by the first torsion coil spring 6 in this manner.
[0030]
7B, the stopper member 41 of the connecting block 11 abuts against the stopper member 42 of the stationary clutch output member 22 until the connecting block 11 makes one rotation in the seat belt feeding direction. When the connection block 11 continues to rotate, the stopper member 41 pushes the stopper member 42 to rotate the clutch output member 22 in the same direction as shown in FIG. Slip the outer periphery (clutch mechanism idling). By doing so, it is possible to prevent the first torsion coil spring 6 from being excessively tightened and damaged at the time of feeding out the seatbelt, and from causing an operation failure at the time of rewinding the seatbelt.
[0031]
The maximum value of the rotation angle of the connecting block 11 from the state of FIG. 7B until the connecting block 11 rotates in the seat belt feeding direction and the stopper members 41 and 42 come into contact with each other is the circle of the stopper members 41 and 42. It is less than 360 degrees determined by the circumferential width, and if the length of the seat belt extended to reach this maximum rotation angle is appropriately set, for example, to about 20 cm, the occupant may move slightly in a forward bending posture or the like. Also, the stopper members 41 and 42 do not come into contact with each other, so that the seat belt can be smoothly fed and wound after the seat belt is mounted.
[0032]
In addition, it is conceivable as a special case that the occupant pulls the seat belt greatly from the state of FIG. 7B until the two stopper members 41 and 42 abut and the clutch spring 23 slips. In such a case, with the above structure, the seat belt cannot be wound by the first torsion coil spring 6, and a problem occurs in which the seat belt remains slack in front of the occupant's chest. The following manual or automatic winding of the seat belt is effective as a countermeasure for this problem.
[0033]
If the seatbelt remains slack in front of the occupant's chest for the above reasons, the occupant notices that the seatbelt has been pulled too much and once removes the tongue inserted in the buckle from the buckle to wind up the seatbelt. . Then, one pulse signal is transmitted from the buckle, the electric motor 31 operates, and winding of the seat belt is started. During this time, the occupant can re-insert the tongue into the buckle to remove the slack in the seat belt.
[0034]
Alternatively, a switch circuit 36 is added to the control system of the electric motor 31 as shown by a chain line in FIG. The switch circuit 36 automatically detects a series of operations in which the two stopper members 41 and 42 come into contact with each other and the clutch spring 23 slips and rotates as shown in FIG. Is a circuit that operates by transmitting the signal. Even if the seat belt is excessively pulled by the addition of the switch circuit 36, the automatic winding is started by the electric motor 31, so that the occupant does not have to worry about occurrence of unexpected loosening of the seat belt. Alternatively, the electric motor 31 may be operated by operating a switch by an occupant who has noticed excessive pulling.
[0035]
Next, a second embodiment of the present invention will be described. As shown in FIG. 8A, in the second embodiment, the clutch input member 121 is inside and the clutch output member 122 is outside. In the first embodiment, since the clutch input member 21 is inside and the clutch output member 22 is outside, the inside and outside of the clutch input / output member are switched. The clutch spring 123 has the same structure as that of the first embodiment, and one end thereof is fixed to the clutch output member 122.
[0036]
The second embodiment is significantly different from the first embodiment in that no stopper member exists between the clutch output member 122 and the connection block 111. Therefore, when the first torsion coil spring 106 is removed in FIG. 8A, the clutch output member 122 and the connection block 111 can be relatively freely rotated.
[0037]
The arm portions 106b and 106c at both ends of the first torsion coil spring 106 are fixed to the clutch output member 122 and the connection block 111, respectively. The coil portion 106a of the first torsion coil spring 106 is slightly separated from the inner peripheral surface of the clutch output member 122 in the initial set state, but the winding shaft 3 is moved in the feeding direction against the first torsion coil spring 106. When rotated, that is, when the first torsion coil spring 106 is rotated in a loosening direction (a direction in which the number of turns is reduced), the outer diameter of the coil portion 106a is enlarged, and the coil portion 106a is configured to be pressed against the inner peripheral surface of the clutch output member 122. ing. The space between the clutch output member 122 and the connection block 111 is narrow on the side of the arm portion 106c and wide on the opposite side of the arm portion 106b.
[0038]
In the seat belt retractor according to the second embodiment described above, since there is no stopper member between the clutch output member 122 and the connection block 111, the amount of rotation of the reel 3 in the feeding direction from the seat belt wearing state is restricted. Is performed by the first torsion coil spring 106. That is, as described above, when the winding shaft 3 rotates in the feeding direction, the outer diameter of the first torsion coil spring 106 expands and presses against the inner peripheral surface of the clutch output member 122. The winding shaft 3 can no longer rotate. In the rotation amount regulation of the first torsion coil spring 106, the number of turns, the axial dimension, and the radial dimension may be appropriately set so as to allow a maximum forward bending posture of the occupant. For example, if the maximum feeding length of the seat belt 1 that can be fed by deformation of the first torsion coil spring 106 from the normal sitting state of the occupant is 20 cm, the number of rotations of the winding shaft 3 in the feeding direction may be two to three times. Since it is sufficient, the number of turns, the axial dimension, and the radial dimension of the first torsion coil spring 106 are set so as to enable such rotation.
[0039]
As long as the first torsion coil spring 106 is elastically deformable, it is desirable to set the friction coefficient so that the clutch spring 123 does not slip. If the clutch spring 123 slips while the first torsion coil spring 106 is still elastically deformable, even if the winding shaft 3 finishes rotating in the winding direction due to the elastic restoring force of the first torsion coil spring 106, the seat belt 1 is not moved. This is because a larger slack remains than at the beginning.
[0040]
The portion where the largest force acts on the first torsion coil spring 106 due to the rotation of the winding shaft 3 in the extending direction is near the winding shaft 3 side, that is, near the arm portion 106c on the input side. It is preferable to make the peripheral space narrow in order to restrict the unreasonable deformation of the coil spring 106 as much as possible. By doing so, the life of the first torsion coil spring 106 can be extended.
[0041]
In FIG. 8A, the coil portion 106a of the first torsion coil spring 106 is pressed against the inner peripheral surface of the clutch output member 122 when the winding shaft 3 rotates in the feeding direction. Similar results can be obtained even when the coil portion 106a of the one-torsion coil spring 106 is pressed against the outer peripheral surface of the connection block 111. In this case, when the winding shaft 3 is rotated in the feeding direction, the first torsion coil spring 106 is wound in a loosening direction (a direction of increasing the number of turns). In this case, since the largest force acts on the arm portion 106b of the first torsion coil spring 106, the surrounding space is narrowed by the arm portion 106b.
[0042]
Next, a third embodiment of the present invention will be described. As shown in FIG. 8B, this embodiment uses a mainspring spring 206 instead of the first torsion coil spring 106 of the second embodiment. The other parts are slightly different in shape from the second embodiment, but hardly change in function. For the sake of simplicity, the same parts as those in the second embodiment are replaced by “2” instead of “1” in the hundreds digit of the corresponding reference numerals, and the description other than the spring 206 is omitted.
[0043]
The outer peripheral end of the mainspring 206 is fixed to the inner peripheral surface of the clutch output member 222, and the inner peripheral end is fixed to the outer peripheral surface of the connection block 211. When the winding shaft 3 rotates in the feeding direction due to the forward bending of the occupant, the mainspring spring 206 is wound up. When the occupant returns to the original posture, the winding shaft 3 is driven in the winding direction by the restoring force of the mainspring spring 206, and unnecessary slack of the seat belt 1 is eliminated.
[0044]
Next, a control example of the electric motor 31 in the second embodiment and the third embodiment will be described with reference to a flowchart of FIG. Note that a rotation sensor (detection of the rotation direction and the number of rotations) is attached to a part of the connection block 111 or 211 for this motor control.
[0045]
This flowchart starts from the initial setting in step 1 when a key switch of, for example, an engine of a vehicle is turned on (start). In step 2, it is determined whether or not the buckle of the seat belt has been released. If the buckle has been released, the motor is instantaneously driven in step 3 (for example, for one second by a timer). Take up. Note that an embodiment in which steps 2 and 3 surrounded by a dashed line are omitted is also possible. In this case, the process immediately shifts from step 1 to step 4. In step 4, it is determined whether or not the seat belt is being withdrawn from the rotation direction of the winding shaft 3. If it is withdrawing, in step 5, it is determined whether or not the counter elapsed value X is larger than the upper limit Y1. The counter elapsed value X represents, for example, the number of revolutions of the reel 3 from the moment when the vehicle door is opened (the feeding direction is positive). If the elapsed counter value X is less than the upper limit value Y1 (slack of the seat belt is within an allowable range), the addition of the counter is continued during withdrawal. Conversely, if the value is equal to or more than the upper limit value Y1, the addition is stopped even during drawing. In step 8, it is determined from the rotation direction of the winding shaft 3 whether or not the seat belt is being wound. If the winding is being performed (by the first torsion coil spring 106 and the mainspring spring 206), the process proceeds to step 9. If the reel is not being taken up or pulled out (the reel is stopped), steps 4 → 8 → 4 are repeated. In step 9, it is determined whether or not the elapsed counter value X is less than the lower limit Y2. If it is less than (e.g., after sliding), the process proceeds to step 11, and if it is more than the lower limit Y2, the subtraction is continued in step 10. . In step 11, the motor is driven in the winding direction, and in the next step 12, the first counter elapsed value X1 is detected. Step 13 is for performing the detection in the subsequent step 16 every predetermined time. In this step 13, it is determined whether or not the elapsed time is longer than T seconds (for example, 2 seconds). Proceeding to step 15, the second counter elapsed value X2 is detected. In step 16, the magnitude relationship between the counter elapsed value X1 and the counter elapsed value X2 is determined. If X1 <X2, there is room for winding and the process returns to step 12 while continuing the motor drive. Conversely, if X2≤X1 (stop rotation or redraw), the process proceeds to step 17 where the motor is stopped.
[0046]
The motor control described above is an example, and it is a matter of course that the present invention is not limited to this. For example, the release of the buckle in step 2 may be replaced by a buckle change (with or without buckle removal / insertion), thereby enabling a quick and cheerful body fit when the seat belt is fastened and a quick start of winding when the seat belt is removed. .
[0047]
Next, a modified example of the speed reduction mechanism 33 of FIG. 1 will be described based on FIG. In FIG. 1, the reduction mechanism is composed of a total of four gears, so a little space is required. However, the reduction mechanism 333 in FIG. 10 uses a worm gear to save space. More specifically, the reduction mechanism 333 includes a worm gear 51 fixed to the rotating shaft of the electric motor 31, a first pinion gear 52 meshed with the worm gear 51, a second pinion gear 53 integrally coaxial with the first pinion gear 52, It is composed of a driven gear 54 meshed with the second pinion gear 53 and fixed to the rotary drive shaft 34. The driving force of the electric motor 31 is transmitted in the order of the worm gear 51 → the first pinion gear 52 → the second pinion gear 53 → the driven gear 54 → the rotary drive shaft 34.
[0048]
In FIG. 10, reference numeral 306 denotes a first torsion coil spring, 311 denotes a connection block, 321 denotes a clutch input member, 322 denotes a clutch output member, and 323 denotes a clutch spring. Although these are slightly different in shape from the above-mentioned members of the same name, they are functionally the same and will not be described in detail.
[0049]
Although the embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and the structures of the rotary drive source 4 and the clutch mechanism 5 and the mounting structure of the first torsion coil springs 6 and 166 and the mainspring spring 206 are not limited thereto. , Changes can be made without impairing its function. For example, a part of a clutch component such as the clutch spring 23 of the clutch mechanism 5 can be incorporated in the speed reduction mechanism 33 of the electric motor 31. Also, one ends of the clutch springs 23, 123, 223 do not necessarily need to be fixed to the clutch output members 22, 122, 222, and the sliding surfaces of the clutch springs 23, 123, 223 are formed on the clutch output members 22, 122, 222. Alternatively, the fastening side may be the clutch input members 21, 121, 221. However, in this case, since the outer diameter side of the clutch springs 23, 123, and 223 serves as a crimping surface when the clutch is locked, it is necessary to take measures to avoid disadvantages in terms of spring durability. Further, in the present invention, it is also possible to make the arrangement relationship between the clutch springs 23, 123, 223 and the first torsion coil springs 6, 106 (spring spring 206) left and right. In short, the rotation drive shaft 34 is the winding shaft 3 in FIGS. 1, 8A and 8B, and the winding shaft 3 is the rotation driving shaft 34. In this way, there is no fundamental change in the force transmission path. 1, 8 (A) and 8 (B) are merely provided in consideration of the durability and the like of the clutch springs 23, 123 and 223. Also, the first torsion coil springs 6, 166 and the mainspring spring 206 have been described as examples of the elastic members used in the present invention. Various deformations such as a member functioning as an elastic member are possible.
[0050]
【The invention's effect】
According to the present invention, a rotary drive source such as a motor that directly winds a seat belt has the function of a large mainspring of a conventional device using two types of large and small mainspring springs. An elastic member (first torsion coil spring or mainspring spring) which automatically winds up when it is fed out has the function of the small mainspring of the conventional device, and these rotary drive source and the first torsion coil spring are used as the mainspring spring. Although it is inexpensive as compared with the above, it is easy to apply, and it is possible to reduce the cost of a high-performance seat belt retractor capable of automatically winding the seat belt in two modes.
[0051]
In addition, a stopper member is provided between the winding shaft and the clutch mechanism to idle the clutch mechanism until the winding shaft makes one rotation when the seat belt is pulled and the winding shaft is rotated in the seat belt feeding direction. In addition, the first torsion coil spring is not excessively tightened when the seat belt is extended, and damage to the first torsion coil spring is avoided.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a seat belt retractor showing an embodiment of the present invention.
FIG. 2 is a side view of the apparatus in FIG. 1;
3 (A) is an enlarged front view of a connecting block used in the apparatus of FIG. 1, FIG. 3 (B) is an enlarged side view, and FIG. 3 (C) is a sectional view taken along line XX of FIG. .
FIG. 4A is an enlarged front view of a first torsion coil spring used in the apparatus of FIG. 1, and FIG. 4B is an enlarged side view.
5 (A) is an enlarged front view of a clutch output member used in the clutch mechanism of the apparatus of FIG. 1, FIG. 5 (B) is an enlarged plan view, and FIG. 5 (C) is an enlarged side view.
FIG. 6A is an enlarged front view of a clutch spring (second torsion coil spring) used in the clutch mechanism of the device in FIG. 1, and FIG. 6B is an enlarged side view.
7 (A) to 7 (E) are front views for explaining the outline of each operation of a pair of stopper members between a coupling block and a clutch output member used in the apparatus of FIG. 1;
FIG. 8A is a sectional view showing a first modification of the embodiment of the present invention, and FIG. 8B is a sectional view showing a second modification of the embodiment of the present invention.
FIG. 9 is a flowchart illustrating a motor control example according to a first modification of the present invention.
FIG. 10 is a sectional view similar to FIG. 1, showing a modified example of the speed reduction mechanism.
[Explanation of symbols]
1 Seat belt
3 reel
4 rotation drive source
5 Clutch mechanism
6 First torsion coil spring (elastic member)
11 Connecting block
21 Clutch input member
22 Clutch output member
23 Clutch spring (second torsion coil spring)
31 Electric motor
33 Speed reduction mechanism
34 rotary drive shaft
35 Timer
36 Switch circuit
41 Stopper member
42 Stopper member
51 Worm gear
52 1st pinion gear
53 2nd pinion gear
54 driven gear
106 Torsion coil spring
123 clutch spring (second torsion coil spring)
206 Spring-spring (elastic member)
223 Clutch spring (second torsion coil spring)
333 Reduction mechanism

Claims (2)

Between the winding shaft of the seat belt and a rotation driving source that applies a rotating force to the winding shaft in the seat belt winding direction, the rotation driving source applies the rotating force to the winding shaft to wind up the seat belt, When the torque value at the time of winding exceeds a predetermined value, the clutch mechanism stops the winding of the seat belt by idling, and the rotational force generated when the seat belt is pulled and the winding shaft is rotated in the seat belt unwinding direction. Along with being elastically deformed, an elastic member for rotating the winding shaft in the seat belt retracting direction with an elastic return force when releasing the tension of the seat belt is disposed ,
By configuring the elastic member with the first torsion coil spring, the rotation of the winding shaft in the seat belt payout direction in the forward bending operation of the occupant is allowed by the elastic deformation of the first torsion coil spring,
The clutch mechanism includes a clutch input member driven by a rotary drive source, a clutch output member connected to the elastic member, and a clutch spring interposed between the two members, wherein the clutch spring is a second torsion coil spring. And one end of the second torsion coil spring is attached to a clutch output member, and the coil portion of the second torsion coil spring is fitted to the outer periphery of the clutch input member with a predetermined frictional force. Seat belt winding device. When the winding shaft is rotated in the seat belt feeding direction between the winding shaft and the clutch mechanism, the winding shaft is mechanically engaged with each other until the winding shaft makes one rotation, but the winding shaft is mechanically engaged until the mechanical engagement. 2. The seat belt retractor according to claim 1, further comprising a pair of stopper members that allow the clutch mechanism to idle due to the reverse rotation force .

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