JP3990617B2 - Webbing take-up device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a webbing retractor constituting a seat belt device for restraining the body of an occupant seated on a seat of a vehicle or the like with a long belt-like webbing belt.
[0002]
[Prior art]
A seat belt device that restrains the body of an occupant seated in a vehicle seat with a long belt-like webbing belt includes a webbing take-up device that is fixed to the vehicle body on the side of the seat. The webbing take-up device includes, for example, a spool (winding shaft) whose axial direction is substantially along the vehicle front-rear direction, and the longitudinal base end side of the webbing belt is locked to the spool. The spool can wind the webbing belt around the outer periphery of the spool, and when the seat belt device is not used, the spool can be wound around the outer periphery of the spool and accommodated.
[0003]
The webbing take-up device is provided with a biasing member such as a spiral spring that biases the spool in the winding direction for winding the webbing belt. The webbing belt is wound by the biasing force of the biasing member. When the webbing belt is mounted on the occupant's body, the slack of the webbing belt is removed by the urging force of the urging member.
[0004]
On the other hand, by winding a certain amount of webbing belt around the spool in a sudden deceleration state of the vehicle, etc., the slight slack called "slack" is eliminated and the restraining force of the occupant's body by the webbing belt is increased. Also, a mechanism for holding the occupant's body more reliably has been considered. This type of mechanism is generally configured to detect the sudden deceleration state of the vehicle with an acceleration sensor and forcibly rotate the spool in the winding direction with the driving force of a driving means such as a motor based on an electric signal from the acceleration sensor. (See Patent Document 1 for an example of such a so-called “motor retractor”).
[0005]
On the other hand, the distance to other vehicles and obstacles in front is detected by a forward monitoring device such as a distance sensor, and when the distance to the preceding vehicle or obstacle is less than a certain value, the motor is operated, A configuration is also conceivable in which the spool is rotated in the winding direction with a rotational force of.
[0006]
[Patent Document 1]
JP 2001-347923 A
[Problems to be solved by the invention]
By the way, in the case of a configuration in which the front of the vehicle is monitored by the front monitoring device as described above, for example, an empty cardboard box or weed that does not affect the vehicle or the occupant even if the vehicle collides, or a roadside structure However, there is a possibility that the front monitoring device may detect it as an obstacle. Such empty cardboard boxes, weeds, road shoulder structures, etc. are basically not recognized as dangerous obstacles by passengers. When the restraint force by the webbing belt is suddenly increased by operating, the passenger feels uncomfortable such as discomfort.
[0008]
Even if there are obstacles that are not particularly dangerous as described above, it is possible to make the structure so that the front monitoring device does not recognize them as obstacles, but the detection accuracy must be extremely high. Problems arise, and excessive costs are required to solve such problems.
[0009]
In consideration of the above facts, the present invention provides a webbing winding that does not give a sense of incongruity such as discomfort due to a sudden winding of the webbing belt when there is an obstacle that is not particularly dangerous. The purpose is to obtain a take-off device.
[0010]
[Means for Solving the Problems]
The webbing take-up device according to claim 1 is a belt-like webbing belt that restrains the body of an occupant seated on a vehicle seat in the mounted state, and a longitudinal base end side of the webbing belt is locked, and its own shaft It is configured to include a winding shaft that winds the webbing belt from the base end side to the outer peripheral portion by rotation in one winding direction, and an output shaft that is directly or indirectly connected to the winding shaft, Driving means for rotating the output shaft in the winding direction by rotating the output shaft with driving force generated by power supply, and forward monitoring for detecting the presence or absence of an obstacle at least within a predetermined range in front of the vehicle Means, a sudden deceleration state detection means for detecting a sudden deceleration state of the vehicle, a forward monitoring means and a sudden deceleration state detection means, and interposed between the drive means and a power source, range When the forward monitoring means detects that the obstacle is present, a low level current is intermittently supplied to the driving means at a predetermined energization timing, and the sudden deceleration state of the vehicle is detected. When the means detects, a high level current whose current value is equal to or greater than the current value of the low level current is continuously or intermittently greater than the low level current. And a control means for supplying to the drive means, and further, when the energization of the low-level current to the drive means is terminated, the energization position of the output shaft is not energized. Is maintained at the rotational position at the end of energization of the low-level current .
[0011]
According to the webbing retractor having the above-described configuration, the passenger sits on the seat of the vehicle, hangs the webbing belt on the body, and engages the tongue plate provided on the webbing belt with the buckle device, for example. The belt is attached to the occupant body.
[0012]
On the other hand, there is an obstacle in front of the vehicle while the vehicle is running, and at least the distance between the vehicle and the obstacle (distance from the vehicle to the obstacle) reaches a predetermined range, which is detected by the forward monitoring means. Then, the control means intermittently supplies a low level current to the drive means.
[0013]
When the output shaft constituting the driving means is rotated by the driving force generated by supplying the low-level current to the driving means, the output shaft is rotated on the winding shaft directly or indirectly connected to the output shaft. transmitted, thereby, the take-up shaft Ru is rotated in the winding direction about the axis thereof. When the winding shaft is rotated in the winding direction, the webbing belt is wound around the outer periphery of the winding shaft from the base end side. Thus, the webbing belt is wound around the winding shaft, so that the slight slack of the webbing belt in the mounted state, so-called “slack” is eliminated, and the restraining force of the occupant's body by the webbing belt increases.
[0014]
Further, when an occupant recognizes an obstacle in front of the vehicle and performs a brake operation, thereby causing a sudden deceleration state of the vehicle, the sudden deceleration state of the vehicle is detected by the sudden deceleration state detection means. The means intermittently supplies a high level current to the drive means.
[0015]
Here, the high-level current has a current value larger than the low-level current. Moreover, unlike the low-level current, the high-level current flows continuously, or even if the current is intermittently supplied, the ratio of the energization time in the energization cycle is greater than the low-level current.
[0016]
Therefore, when a high level current is supplied to the driving means, a larger driving force is generated in a shorter time than when a low level current is supplied. The rotation of the output shaft that rotates with a large driving force generated in such a short time is transmitted to the take-up shaft, so that the take-up shaft is suddenly rotated in the take-up direction, and the restraining force by the webbing belt is reduced for a short time. Suddenly rises. Thereby, it is possible to restrict the movement of the occupant's body forward of the vehicle due to inertia in the vehicle sudden deceleration state by the restraining force of the webbing belt.
[0017]
As described above, in the present webbing take-up device, when the distance between the vehicle and the obstacle reaches a predetermined range, a low-level current is intermittently supplied. For this reason, even if the winding shaft does not rotate suddenly but rotates intermittently or continuously, the rotation speed becomes relatively slow. Therefore, when a low level current is passed, the winding shaft rotates and the slack of the webbing belt is removed, but the restraining force of the webbing belt does not rise rapidly, and the passenger wearing the webbing belt suddenly increases the restraining force. There will be no uncomfortable feeling due to discomfort.
[0018]
In addition, when an occupant performs a braking operation and enters a sudden deceleration state after the obstacle has entered the predetermined range in front of the vehicle as described above, a high-level current is sent to the driving means and suddenly wound. Before the take-up shaft winds the webbing belt, slack is removed in advance by passing a low-level current through the driving means. For this reason, the restraining force by the webbing belt can be increased within a short period of time after the high-level current is applied, and the occupant's body can be reliably held.
[0022]
On the other hand , in the present webbing take-up device, the control means supplies a low level current to the driving means based on the obstacle detection signal of a predetermined level from the front monitoring means. When there is no obstacle in front of the vehicle without suddenly decelerating, the supply of the low level current to the driving means is stopped and the high level current is not supplied.
[0023]
Here, in the present webbing take-up device, as described above, when the supply of the low level current to the drive means is stopped and the high level current is not supplied, the output shaft is connected to the drive means. The rotation position is maintained at the time when the supply of the low level current to is stopped. Accordingly, in this state, the slack is removed, and the restraining force by the webbing belt is slightly increased as compared to before the low level current is supplied.
[0024]
In this way, the slack of the webbing belt is removed and the restraining force by the webbing belt is maintained in a slightly increased state, so that the obstacle is again positioned within a predetermined range in front of the vehicle, and the occupant When the brake operation is performed and the vehicle is suddenly decelerated, the restraining force by the webbing belt can be increased more quickly than a certain value.
In the present invention, the rapid deceleration detection means is not limited to a specific mode as long as it can detect the sudden deceleration state of the vehicle. Therefore, the acceleration detection means such as an acceleration sensor that detects the acceleration of the vehicle, particularly the acceleration (deceleration) in the deceleration state, may be used as the sudden deceleration detection means. The configuration may be such that the change in the hydraulic pressure is detected by pressure detection means such as a pressure sensor, and the determination means determines whether or not an abrupt braking operation has been performed based on the detection result.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
<Configuration of the present embodiment>
FIG. 1 is a front sectional view schematically showing the overall configuration of a webbing take-up device 10 according to an embodiment of the present invention.
[0026]
As shown in this figure, the webbing take-up device 10 includes a frame 12. The frame 12 includes a substantially plate-like back plate 14. The back plate 14 is fixed to the vehicle body by fastening means (not shown) such as bolts, so that the webbing take-up device 10 is attached to the vehicle body. ing. A pair of leg plates 16 and 18 extend in parallel from both ends of the back plate 14 in the width direction, and a spool 20 as a winding shaft manufactured by die casting or the like is rotatable between the leg plates 16 and 18. Has been placed.
[0027]
The spool 20 includes a substantially cylindrical spool body 22 and a pair of flange portions 24 and 26 formed in a substantially disk shape at both ends of the spool body 22, respectively. Yes.
[0028]
The spool main body 22 has a base end portion of a webbing belt 28 formed in a long band shape fixed between the flange portions 24 and 26. When the spool 20 is rotated to one side around its axis, the webbing belt 28 is The spool body 22 is wound around the outer periphery of the spool body 22 from the base end side. Further, when the webbing belt 28 is pulled from the front end side, the webbing belt 28 wound around the outer peripheral portion of the spool body 22 is pulled out, and accordingly, the rotation direction when winding the webbing belt 28 (hereinafter referred to as this direction). Is referred to as “winding direction” for the sake of convenience, and the spool 20 rotates (hereinafter, the rotation direction of the spool 20 when the webbing belt 28 is pulled out is referred to as “drawing direction” for convenience).
[0029]
The one end side of the spool 20 on the side opposite to the flange portion 26 of the flange portion 24 penetrates a circular hole 30 formed in the leg plate 16 substantially coaxially and protrudes to the outside of the frame 12. A case 32 is disposed outside the frame 12 on the leg plate 16 side. The case 32 is disposed facing the leg plate 16 along the axial direction of the spool 20 and is fixed to the leg plate 16. The case 32 is generally open toward the leg plate 16, and one end side of the spool 20 that penetrates the circular hole 30 enters the inside of the case 32 and is rotatably supported by the case 32.
[0030]
Further, a spiral spring 34 is disposed inside the case 32. The spiral spring 34 has an end on the outer side in the spiral direction locked with the case 32, and an end on the inner side in the spiral direction locked with the spool 20. When the spool 20 is rotated in the pull-out direction from a neutral state where no special load is applied, the spiral spring 34 generates a biasing force in the winding direction and biases the spool 20 in the winding direction. Therefore, basically, when the tensile force applied to the webbing belt 28 to be pulled out from the spool 20 is released, the urging force of the spiral spring 34 rotates the spool 20 in the winding direction so that the webbing belt 28 is wound around the spool 20. It has a structure that can be taken.
[0031]
On the other hand, the other end side of the spool 20 on the opposite side of the flange portion 24 of the flange portion 26 penetrates the ratchet hole 36 of the internal tooth formed in the leg plate 18 substantially coaxially and protrudes to the outside of the frame 12. . A lock mechanism 38 is disposed outside the frame 12 on the leg plate 18 side. The lock mechanism 38 includes a case 40. The case 40 is disposed to face the leg plate 18 along the axial direction of the spool 20 and is fixed to the leg plate 18.
[0032]
A ratchet gear 42 constituting the lock mechanism 38 is accommodated inside the case 40 so as to be coaxial with the spool 20 and relatively rotatable. The ratchet gear 42 has a shallow cylindrical shape opened on the opposite side to the axial leg plate 18, and ratchet teeth are formed on the outer periphery thereof.
[0033]
A lock base 44 is accommodated inside the ratchet gear 42. The lock base 44 is provided coaxially and integrally with the spool 20, and thus rotates integrally with the spool 20 by the rotation of the spool 20. The lock base 44 is provided with a biasing means such as a compression coil spring (not shown). A part of the urging means is engaged with the ratchet gear 42 described above. When the lock base 44 rotates, the urging means rotates together with the lock base 44 and applies an urging force along the rotation direction to the ratchet gear 42. To do. Therefore, the ratchet gear 42 is originally rotatable relative to the spool 20, but the ratchet gear 42 is spooled by the biasing force applied from the biasing means when the lock base 44 rotates integrally with the spool 20. It is the structure which rotates following 20 rotation.
[0034]
On the other hand, the lock plate 46 is supported by the lock base 44 inside the ratchet hole 36 described above. The lock plate 46 can move toward and away from the inner teeth of the ratchet hole 36 while being supported by the lock base 44. The lock plate 46 is engaged with the ratchet gear 42 described above. When the ratchet gear 42 rotates relative to the lock base 44 in the winding direction described above, the ratchet hole 36 is interlocked with this rotation. The inner teeth of the ratchet hole 36 are engaged with each other.
[0035]
A sensor frame 48 is disposed below the ratchet gear 42 in the radial direction. The sensor frame 48 has a mounting portion (not shown) that is curved with a predetermined curvature and opens upward, and the sensor ball 50 is mounted on the mounting portion. Further, an engagement plate 52 is provided above the sensor ball 50. The engagement plate 52 is attached to the sensor frame 48 so as to be pivotable up and down. When the sensor ball 50 rolls on the mounting portion described above and is displaced upward, it presses against the sensor ball 50 from above. Rotate. Further, an engagement claw 54 is formed on the engagement plate 52. The engagement claw 54 has its tip opposed to the ratchet teeth of the ratchet gear 42. When the engagement plate 52 rotates upward, the engagement claw 54 meshes with the ratchet teeth of the ratchet gear 42, and the ratchet gear 42 rotates. It has a configuration to regulate.
[0036]
On the other hand, a motor 60 as a driving means is disposed below the spool 20 and between the leg plate 16 and the leg plate 18. A gear 64 is coaxially and integrally provided on the output shaft 62 of the motor 60.
[0037]
A gear 66 having a larger diameter than that of the gear 64 is disposed above the gear 64 in the radial direction. The gear 66 meshes with the gear 64 while being rotatably supported around an axis parallel to the spool 20 by the support plate 68 and the leg plate 16 provided between the leg plates 16 and 18. A gear 70 having a smaller diameter than the gear 66 is provided coaxially and integrally with the gear 66 on the side of the gear 66 in the axial direction.
[0038]
Further, a clutch 72 is provided on the upper side of the gear 70 in the radial direction. The clutch 72 includes an external gear 74 formed in a ring shape. The gear 74 is coaxial with the spool 20 and is provided so as to be relatively rotatable, and both ends in the axial direction are closed by disk-like members (not shown). A cylindrical adapter 76 is provided coaxially with the spool 20 inside the gear 74. The adapter 76 is provided coaxially and integrally with the spool 20, and allows the disk-like member, and thus the gear 74, to rotate around the spool 20 while passing through the disk-like member that closes both ends of the gear 74. It is pivotally supported.
[0039]
A connecting member such as a pawl that swings due to centrifugal force is accommodated inside the gear 74. For example, the connecting member is supported by the disk-shaped member described above, can rotate together with the gear 74, and swings with a centrifugal force to engage with the outer peripheral portion of the adapter 76 to engage the gear 74 and the adapter 76. Are coupled to each other so that the rotational force of the gear 74 can be transmitted to the adapter 76, and thus to the spool 20.
[0040]
That is, the clutch 72 has a structure capable of transmitting the rotation on the gear 74 side (the output shaft 62 side of the motor 60) to the spool 20 but not transmitting the rotation of the spool 20 to the gear 74.
[0041]
On the other hand, as shown in FIG. 1, the motor 60 described above is electrically connected to a battery 84 mounted on the vehicle via a driver 82 that constitutes control means, and current from the battery 84 is supplied to the driver 82. The motor 60 is configured to rotate the output shaft 62 in the forward direction or the reverse direction. The driver 82 is connected to an ECU 86 that is configured by a microcomputer or the like and constitutes a control unit, and the ECU 86 is further connected to a front monitoring device 88 as a front monitoring unit.
[0042]
The front monitoring device 88 includes an infrared sensor 90 provided near the front end of the vehicle. The infrared sensor 90 emits infrared rays in front of the vehicle and is referred to as an “obstacle” for convenience, including other vehicles and obstacles that are running or stopped in front of the vehicle (hereinafter, including other vehicles that are running or stopped). The infrared sensor 90 reflected at (1) is received. The front monitoring device 88 includes a calculation unit 92.
[0043]
The computing unit 92 computes the distance to the obstacle based on the time required to return to the infrared sensor 90 after being reflected by the obstacle after infrared rays are emitted from the infrared sensor 90. The calculation unit 92 outputs an obstacle detection signal Os to the ECU 86 based on the calculation result. The obstacle detection signal Os is at a low level if the distance to the obstacle is equal to or greater than a predetermined value, and is at a high level if the distance to the obstacle is less than the predetermined value.
[0044]
The ECU 86 is connected to an acceleration sensor 98 that constitutes a sudden deceleration state detecting means as an acceleration detecting means provided at an appropriate position of the vehicle. The acceleration sensor 98 detects acceleration (ie, deceleration) when the vehicle decelerates. The acceleration sensor 98 basically outputs a low-level acceleration detection signal Bs to the ECU 86, but detects an acceleration at a predetermined change rate, that is, an acceleration corresponding to a vehicle sudden deceleration state during sudden braking or the like. In such a case, a high level acceleration detection signal Bs is output to the ECU 86.
[0045]
<Operation and effect of the present embodiment>
Next, the operation and effect of the present embodiment will be described through the operation of the webbing take-up device 10.
[0046]
First, the basic operation of the webbing take-up device 10 will be described.
[0047]
In the webbing take-up device 10, when the webbing belt 28 is pulled while pulling a tongue plate (not shown) with the webbing belt 28 wound in layers on the spool 20, a spiral that urges the spool 20 in the winding direction. The webbing belt 28 is pulled out while rotating the spool 20 in the pulling direction against the urging force of the spring 34. In this way, with the webbing belt 28 pulled out, the tongue plate is inserted into a buckle device (not shown) while the webbing belt 28 is hung around the front of the occupant seated on the seat, and the tongue plate is held by the buckle device. Thus, the webbing belt 28 is attached to the occupant's body (hereinafter simply referred to as “attached state”).
[0048]
Further, when the webbing belt 28 is pulled out and the spool 20 is rotated in the pull-out direction in order to mount the webbing belt 28, the spiral spring 34 is tightened and the spool 20 is biased toward the winding direction. Power increases. Therefore, in the mounted state, since the urging force of the spiral spring 34 acts to wind the webbing belt 28 around the spool 20, the webbing belt 28 basically fits the occupant's body with this urging force. The webbing belt 28 restrains and holds the occupant's body with a force corresponding to the urging force at this time.
[0049]
On the other hand, since the holding of the tongue plate by the buckle device is released and the tongue plate comes out of the buckle device, the force for maintaining the webbing belt 28 in the pulled-out state against the urging force of the spiral spring 34 is released. The spring 34 rotates the spool 20 in the winding direction with an urging force. The webbing belt 28 drawn out by the rotation of the spool 20 in the winding direction is wound around the outer periphery of the spool 20 in a layered manner, whereby the webbing belt 28 is stored.
[0050]
Here, since the spool 20 is fitted to the adapter 76 of the clutch 72, when the spool 20 is rotated for pulling out or winding the webbing belt 28, the adapter 76 is rotated. However, as described above, since the clutch 72 does not transmit the rotation of the adapter 76 to the gear 74, the gear 74 does not rotate in this state. Therefore, the rotation of the spool 20 is not transmitted to the output shaft 62 of the motor 60 via the gears 74, 70, 68, 66, 64.
[0051]
On the other hand, in the running state of the vehicle, the calculation unit 92 calculates the distance to the obstacle ahead of the vehicle based on the detection result of the infrared sensor 90 of the front monitoring device 88. For example, when there is no obstacle ahead of the vehicle, or there is an obstacle but the distance from the obstacle to the vehicle is equal to or greater than a predetermined value, the low-level signal Os is output from the calculation unit 92 ( (See the state up to time T1 in the time chart of FIG. 2).
[0052]
On the other hand, when the distance from the vehicle to the obstacle ahead is less than a predetermined value, a high level signal Os is output from the calculation unit 92 (a state between times T1 and T2 in the time chart of FIG. 2). See).
[0053]
When the high level signal Os from the arithmetic unit 92 is input to the ECU 86, the ECU 86 outputs a predetermined operation signal to the driver 82. The driver 82 to which the operation signal is input in this state supplies the motor 60 with a current I having a current value IA (hereinafter, the current I having a current value IA flowing in this state is referred to as “low level current IA” for convenience). Shed. Here, as shown in the time chart of FIG. 2, the low-level current IA is a rectangular pulse current having an energization time of dT, and while the high-level signal Os from the calculation unit 92 is being input to the ECU 86, It is sent to the motor 60 at a constant cycle.
[0054]
As described above, when the low level current IA is caused to flow through the motor 60, the motor 60 is driven to rotate the output shaft 62. The rotation of the output shaft 62 is transmitted to the gear 74 via the gears 64 to 70. Further, when the gear 74 is rotated, the connecting member mechanically connects the gear 74 and the adapter 76, whereby the adapter 76 rotates in the winding direction. When the adapter 76 rotates in the winding direction, the spool 20 integrated with the adapter 76 rotates in the winding direction and winds the webbing belt 28. In this way, when the webbing belt 28 is wound around the spool 20, so-called “slack”, which is a slight slack of the webbing belt 28, is removed, and as shown in FIG. Ascend to F1.
[0055]
Further, when the occupant performs the steering operation from this state and no obstacle exists in front of the vehicle, the low-level signal Os is output again from the calculation unit 92. When the low level signal Os is input to the ECU 86 again, the ECU 86 outputs a predetermined operation signal to the driver 82, and the driver 82 to which the operation signal is input stops energizing the motor 60. As a result, the motor 60 stops and the winding of the webbing belt 28 by the spool 20 based on the driving force of the motor 60 is also stopped.
[0056]
However, since the motor 60 is only stopped in this way and is not reversely driven or the like, the rotational position of the output shaft 62 remains at the rotational position when the motor 60 is stopped. For this reason, basically, the rotational position of the spool 20 does not change particularly, so the slack is removed and the restraining force F is maintained in the state of F1.
[0057]
Next, from this state, when the time T3 has elapsed, an obstacle appears again in front of the vehicle, and when the distance from the vehicle to the obstacle is less than a predetermined value, as in the case described above, The signal Os is input to the ECU 86, and a low level current IA flows through the motor 60. As a result, the spool 20 rotates again in the winding direction to wind up the webbing belt 28. For this reason, the restraining force F by the webbing belt 28 rises to F2 larger than F1.
[0058]
Further, when the passenger performs an abrupt braking (braking) operation after the time T4 has elapsed, the vehicle is suddenly decelerated. When the acceleration sensor 98 detects the acceleration in this state, the signal Bs at the Low level is detected until then. , The acceleration sensor 98 outputs a high level signal Bs to the ECU 86. The ECU 86 to which the high-level signal Bs is input outputs a predetermined operation signal to the driver 82, and the driver 82 to which this operation signal is input has the current I of the current value IB (hereinafter, the current value flowing in this state). The current I of IB is referred to as “low level current IB” for the sake of convenience.
[0059]
Here, the high level current IB has a current value IB higher than the current value IA of the low level current IA, and the low level current IA is intermittently passed through the motor 60 in the form of a rectangular pulse. The high level current IB is continuously supplied to the motor 60. For this reason, the driving force generated by the motor 60 becomes larger than the driving force generated by the flow of the low level current IA, thereby causing the output shaft 62 to rapidly rotate in a constrained manner. Therefore, when the rotation of the output shaft 62 is transmitted to the spool 20, the spool 20 rotates at a high speed in the winding direction, and the webbing belt 28 is rapidly wound. As a result, as shown in the time chart of FIG. 2, the restraining force F of the webbing belt 28 rapidly increases after the time T4 has elapsed.
[0060]
Thus, when the occupant recognizes an obstacle in front of the vehicle and performs a braking operation, the restraining force of the webbing belt 28 indicates that the occupant moves to the front side of the vehicle when the vehicle suddenly decelerates. Can be surely prevented.
[0061]
Here, in the webbing retractor 10, when the distance to the obstacle ahead of the vehicle is less than a predetermined value, the rectangular pulse-shaped low level current IA having a current value sufficiently lower than the high level current IB. Is intermittently passed to the motor 60. For this reason, even if the spool 20 does not rotate abruptly but rotates intermittently or continuously, the rotation speed becomes relatively slow. For this reason, the restraining force of the webbing belt 28 does not rapidly increase, and the occupant wearing the webbing belt 28 does not feel uncomfortable feelings such as discomfort caused by the sudden increase of the restraining force.
[0062]
Further, after the distance to the obstacle becomes less than the predetermined value as described above, if the vehicle is suddenly decelerated by a braking operation or the like by the occupant, the high-level current IB is caused to flow to the motor 60, and thereby suddenly Although the restraining force by the webbing belt 28 is increased, the slack is previously removed by causing the low level current IA to flow through the motor 60 before the high level current IB flows. For this reason, the restraining force by the webbing belt 28 is increased within a short period of time after the high-level current IB is supplied, and the occupant's body can be reliably held.
[0063]
Further, as described above, when the high level signal Bs is not output after the output of the high level signal Os is finished, the rotation position of the output shaft 62 stops the power supply to the motor 60. Thus, the slack is basically removed, and the restraining force by the webbing belt 28 is slightly increased.
[0064]
Therefore, after that, when the distance to the obstacle again becomes less than the predetermined value, and further, when the occupant performs a braking operation and the vehicle is suddenly decelerated, the restraining force by the webbing belt 28 is more quickly fixed. It can be raised above.
[0065]
In the present embodiment, the high level current IB is continuously supplied. However, the energization time in the energization cycle is larger than the ratio of the energization time of the low level current IA in the energization cycle of the low level current IA. If it is larger, the high level current IB may flow intermittently.
[0066]
Further, in the present embodiment, the sudden deceleration state detecting means is constituted by the acceleration sensor 98 as the acceleration detecting means for detecting the acceleration (ie, deceleration) when the vehicle decelerates. However, the sudden deceleration detection means is not limited to the acceleration detection means for detecting the acceleration (ie, deceleration) when the vehicle decelerates like the acceleration sensor 98, and as a result, the sudden deceleration state of the vehicle is detected. Any configuration can be used.
[0067]
Therefore, for example, the sudden deceleration detection means detects a change in the hydraulic pressure in the brake cylinder by the pressure detection means such as a pressure sensor, and further determines whether or not a sudden braking operation has been performed based on the detection result. It may be configured to.
[0068]
【The invention's effect】
As described above, in the webbing take-up device according to the present invention, when the front monitoring means detects an obstacle in front of the vehicle, the low-level current is intermittently supplied to the driving means to relatively slowly webbing. When the belt is wound and the sudden deceleration state detecting means detects the vehicle sudden deceleration state, a high level current is supplied to the driving means to rapidly wind the webbing belt. Therefore, when there is no particular danger to the obstacle in front of the vehicle and it is not necessary to perform a sudden braking operation, a low level current is intermittently applied to the driving means, so that the webbing belt is gently wound up. Therefore, the passenger wearing the webbing belt does not feel uncomfortable or uncomfortable.
[Brief description of the drawings]
FIG. 1 is a front view showing an outline of the overall configuration of a webbing take-up device according to an embodiment of the present invention.
FIG. 2 is a time chart showing the relationship among signals, current flowing in driving means, and binding force in the webbing take-up device according to one embodiment of the present invention.
[Explanation of symbols]
10 Webbing take-up device 20 Spool (winding shaft)
28 Webbing belt 60 Motor (drive means)
62 Output shaft 82 Driver (control means)
86 ECU (control means)
88 Forward monitoring device (forward monitoring means)
98 Acceleration sensor (rapid deceleration state detection means)

Claims (1)

A long belt-like webbing belt that restrains the body of an occupant seated in a vehicle seat in the mounted state;
The webbing belt is locked on the base end side in the longitudinal direction, and is wound around the axis in one winding direction to wind the webbing belt from the base end side to the outer periphery, and
A drive that includes an output shaft that is directly or indirectly connected to the take-up shaft, and that rotates the output shaft in the take-up direction by rotating the output shaft with a drive force generated by power supply. Means,
Forward monitoring means for detecting the presence or absence of an obstacle within a predetermined range at least in front of the vehicle;
A sudden deceleration state detection means for detecting a sudden deceleration state of the vehicle;
When connected to the forward monitoring means and the sudden deceleration state detecting means, and interposed between the driving means and a power source, the forward monitoring means detects that the obstacle exists within the predetermined range. In addition, when the low-level current is intermittently supplied to the driving means at a predetermined energization timing, and the sudden deceleration state detecting means detects the sudden deceleration state of the vehicle, the current value is the current of the low level current. A control means for supplying a high level current equal to or greater than a value to the drive means intermittently with a ratio that the energization time occupies continuously or in an energization cycle larger than the low level current;
In addition, even if energization of the low-level current to the driving means is completed, if the energization of the high-level current is not performed, the rotational position of the output shaft is energized by the energization of the low-level current. Maintain the rotational position at the end,
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