JPH0425400Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of application of the invention] The present invention relates to a webbing take-up force suppressing device used in a seat belt device for protecting occupants in vehicle emergencies to suppress webbing take-up forces applied to the occupant. .

[Background Art] In a seat belt device, a restraining webbing that is attached to an occupant is wound around a winding shaft with a biasing force, thereby bringing the webbing into close contact with the occupant.

However, when the vehicle is running, the occupant feels pressure to take up the webbing through the webbing, causing fatigue. For this reason, various webbing take-up force suppressing devices have conventionally been proposed that suppress the webbing take-up force after the webbing is attached to eliminate the feeling of pressure on the occupant.

However, with such conventional webbing take-up force suppressing devices, after the webbing has been pulled out from the take-up shaft by a predetermined length corresponding to the length of the webbing worn by the passenger, the webbing is automatically taken up by a small amount onto the take-up shaft. Therefore, the winding force of the webbing is suppressed. For this reason, if the occupant is not seated correctly on the seat with the webbing attached, and there is a gap between the occupant and the seat, and the webbing is attached, and from this state the occupant is moved slightly forward, This causes a state in which the winding force is inhibited, which causes a large gap to be formed between the occupant and the webbing when the occupant assumes an actual running position. These conventional problems are caused by the inability to properly detect the state in which the occupant is wearing the webbing, and the conventional detection means uses a planetary gear mechanism to decelerate the rotation of the take-up shaft and then slows down the rotation of the take-up shaft. Although the structure is complicated, it is impossible to accurately detect the rotational position of the winding shaft.

[Purpose of the invention] The present invention is a webbing take-up force restraint that can reliably and easily detect when the occupant is in the normal driving position, and can minimize the gap between the webbing and the occupant. The purpose is to obtain equipment.

[Summary of the invention] In the present invention, the rotation of the winding shaft is converted into a minute displacement in the axial direction by means of a screw changing means, and the minute displacement in the axial direction is detected by the means for detecting the amount of webbing pulled out to detect the amount of webbing pulled out. By suppressing the biasing force of the elastic body acting on the take-up shaft when the webbing is attached to the webbing by the webbing pull-out amount detecting means, it is possible to accurately detect the normal driving posture of the occupant.

[Example of idea] Embodiments of the present invention will be described below with reference to the drawings.

1 to 3 show a webbing retractor 10 to which a webbing retractor force suppressing device according to the present embodiment is applied.

In this webbing retractor 10, the frame 12
is fixed to the vehicle body 16 with mounting bolts 14.

Leg plates 18 and 20 that are bent at right angles from both sides of the frame 12 and extend parallel to each other support the vicinity of both ends of a winding shaft 22, and a passenger is restrained at the center of the winding shaft 22. The base end of the webbing 24 is fixed. A tongue plate 25 is attached to the tip of the webbing 24 (see FIG. 4), and the space between the tongue plate 25 and the winding shaft 22 serves as a mounting portion for an occupant (not shown).

A sheet 26 is fixed to the outside of the leg plate 20, and a connecting shaft 30 is inserted through a circular hole 28 formed in this sheet 26. This connecting shaft 30
is connected to the end of the winding shaft 22 to rotate the connecting shaft 30 integrally with the winding shaft 22.
The winding shaft 22 and the connecting shaft 30 may be formed integrally.

The connecting shaft 30 has a pinion 32 in the middle and a flat shaft 3.
4, and a small diameter shaft 36 is formed at the tip of this flat shaft 34.

A rectangular hole 40 formed in the shaft core of the gear wheel 38 is fitted into the flat shaft 34, so that the gear wheel 38 rotates integrally with the winding shaft 22 via the connecting shaft 30. ing. A ratchet 42 is carved on the outer periphery of the gear wheel 38, and a boss portion 44 formed coaxially with the ratchet gear 42 is provided with a slit 46 in the tangential direction, into which the inner end of the mainspring spring 48 is inserted. ing. The outer end of this mainspring spring 48 is locked to a cover 50 attached to the outside of the leg plate 20.

Therefore, the mainspring spring 48 applies a biasing force to the winding shaft 22 to bias the webbing 24 in the winding direction (in the direction of arrow A in FIG. 2), but when the rotation of the gear wheel 38 is stopped, the winding stops. The webbing winding force shown in FIG. 22 on the take-up shaft is in a restrained state.

A seat 26 is attached to the pinion 32 of the connecting shaft 30.
Gears 54 supported by pins 52 are engaged. A male screw 56 coaxially protrudes from the gear 54, and a nut 58 is screwed into the male screw 56. A pin 60 passes through the nut 58 at a location eccentric from the axis, and this pin 60 projects integrally from the cover 50. Therefore, when the male screw 56 rotates, this nut 58 receives the rotational force, but since rotation is prevented by the pin 60, it moves only in the axial direction. In other words, this nut 58 constitutes a thread converting means that moves in the axial direction according to the amount of rotation of the winding shaft 22.

The tip of a leaf spring 62 attached to the seat 26 and the leg plate 20 is in contact with the nut 58.
A resistance wire strain gauge 63 is attached to the middle part of the leaf spring 62, and the amount of strain in the leaf spring 62, that is, the amount of strain in the nut 58 is determined by a strain gauge (not shown).
The rotational position of the winding shaft 22 can be detected by detecting the amount of movement of the nut 58 in the axial direction. It constitutes a webbing pull-out amount detection means for detecting the pull-out amount. This strain gauge is designed to input its output to a control device 64 (FIG. 4) which is a driving means.

On the other hand, the seat 26 has a pin 66 that connects the rocker arm 6.
8 is pivoted. A bowl 70 is pivotally supported at one end of the rocker arm 68 by a pin 72.
This bowl 70 is urged in a direction toward the ratchet gear 42 by the urging force of a torsion coil spring 74.

A suction plate 76 provided at the other end of the rocker arm 68 corresponds to a solenoid 78 fixed to the cover 50. When this suction plate 76 is attracted by a solenoid 78, the rocker arm 68 engages the bowl 70 with the ratchet gear 42.

In this meshed state, the ratchet gear 42 stops rotating in the webbing take-up direction, so the biasing force of the mainspring spring 48 does not act on the take-up shaft 22, and the webbing take-up force is suppressed. Since the bowl 70 is rotatable relative to the rocker arm 68, the attachment error of the rocker arm 68 is absorbed and the bowl 70 is reliably engaged with the ratchet gear 42.

The rocker arm 68 biases the bowl 70 in a direction away from the ratchet gear 42 by the biasing force of a torsion coil spring 80. Further, the solenoid 78 constitutes a holding mechanism together with the ratchet gear 42 and the pawl 70, and forms a state in which the winding force of the winding shaft is inhibited.

The solenoid 78 is driven by the control device 64 and the suction plate 7 of the rocker arm 68 is driven by the vehicle power supply.
Aspirate 6.

The control device 64 controls the state in which the webbing is attached, that is, the state in which the webbing 24 is buckled up by the occupant (webbing pull-out length t=0 in FIG. 5).
is detected by the strain gauge 63, and the maximum unwinding position of the winding shaft during a predetermined time _t0 (for example, about 10 seconds) from this state is memorized, that is, the minimum withdrawal amount _l0 , and this After the elapsed time t ₀ , the take-up shaft reaches the webbing maximum unwinding position l ₀ or the webbing pull-out position l ₀ +△l that exceeds l ₀ , that is, the webbing maximum unwinding position
The solenoid 78 is designed to be sucked at a position where the webbing is pulled out by a predetermined amount corresponding to the appropriate slack amount than _l0 .

In addition, the control device 64, as shown in FIG.
Buckling device 82 with which tongue plate 25 engages
When the tongue plate 25 engages with the buckle 82 and the passenger puts on the webbing 24, it closes and sends a signal to the control device 64.

Next, the operation of this embodiment will be explained.

When the occupant is not wearing the webbing, the webbing 24 is wound onto the take-up shaft 22 by the maximum amount, and from this state the occupant pulls out the webbing 24 and attaches it.

When the occupant pulls out the webbing 24 after the buckle and tongue are latched, the strain gauge 63 detects the amount of the webbing 24 pulled out, and as shown in FIG _.
( For example, when the passenger returns to the driving position after the back-up state in which the tongue plate 25 attached to a part of the webbing is engaged with the buckle device 82 attached to the vehicle body in order to attach the webbing 24. When the webbing is pulled out, the amount of webbing pulled out becomes the minimum). The occupant enters the driving position after wearing the webbing, but it is preferable that a predetermined time t ₀ elapses immediately before the occupant assumes the driving position.
If the occupant pulls out more than a certain amount (△l) of the webbing 24 due to abdominal breathing, etc. after _t0 has passed, or when the occupant is in the maximum retracting state, the
At the l ₀ +△l position, the control device 64 operates the solenoid 78, so the pawl 70 engages with the ratchet gear 42, and the rotation of the take-up shaft 22 in the webbing take-up direction is stopped, and the webbing take-up force is inhibited. Become.

As a result, the winding force of the mainspring spring 48 does not act on the occupant, so that the occupant can enjoy a comfortable driving condition. Furthermore, when the occupant moves his/her upper body significantly to operate the instruments in front of the passenger seat while driving, the strain gauge 63 detects the rotation of the take-up shaft and de-energizes the solenoid 78. As a result, the crew member can
The upper body can be moved by the urging force of the mainspring spring 48, and when the user returns to the original driving position, the solenoid 78 is energized at the position of the webbing drawer length l ₀ +△l, and the webbing retracting force is suppressed. .

When the occupant releases the webbing device, the buckle switch 84 opens, which causes the control device 64 to de-energize the solenoid 78 and turn the take-up shaft 2
The biasing force of the mainspring spring 48 acts on the webbing 24 due to the biasing force of the mainspring spring 48.
The maximum amount of can be wound onto the winding shaft 22, resulting in a fully wound state.

In the above embodiment, the control device 64 is configured to memorize the maximum unwinding position within the time t ₀ after the webbing 24 is pulled out from the fully wound state, but the maximum unwinding position within the time t 0 after the tongue plate 25 is engaged with the buckle device 82 is stored. The configuration may be such that the maximum rewind position within ₀ hours is stored, or the configuration may be such that the maximum rewind position of the webbing is stored within a predetermined time after the webbing is pulled out when the webbing is attached. Further, in the above embodiment, the webbing pull-out amount detecting means for detecting the axial movement amount of the nut 58 and the webbing pull-out amount is composed of a strain gauge and a strain meter, but other webbing pull-out amount detecting means may be used. is also applicable.

[Effects of the invention] As explained above, in the webbing take-up force suppressing device according to the present invention, the rotation of the take-up shaft is converted into a minute displacement in the axial direction by the screw conversion means, and this minute displacement in the axial direction is detected by the webbing draw-out amount detection means. By detecting this, it is possible to detect the amount of webbing that has been pulled out, and thereby detect the state in which the webbing is worn by the occupant.
Despite its simple structure, the rotation of the take-up shaft is reliably converted into minute axial displacement of the screw conversion means.
Detection of minute displacements in the axial direction, that is, detection of the amount of webbing pulled out, is performed stably, and the detection accuracy is increased, so that the normal driving posture of the occupant can be accurately detected.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a webbing retractor to which an embodiment of the webbing retracting force suppressing device according to the present invention is applied, FIG. 2 is a sectional view taken along the line -- in FIG. 1, and FIG. Figure 4 is an explanatory diagram showing the relationship between the tongue plate and the buckle device, Figure 5 is an exploded perspective view of
The figure is a diagram showing the correspondence between webbing pull-out length and elapsed time. 10...Webbing take-up device, 22...Take-up shaft, 24...Webbing, 42...Ratchet gear, 48...Spring spring, 56...Male thread, 5
8...Nut, 60...Pin, 63...Resistance wire strain gauge.

Claims (1)

[Claims for Utility Model Registration] (1) A take-up shaft that winds up occupant restraint webbing and an elastic body that biases this take-up shaft in the webbing winding direction are rotated by a microscopic displacement in the axial direction. a webbing extraction amount detection means for detecting a minute axial displacement of the screw conversion means to detect the webbing extraction amount; and a webbing extraction amount detection means that detects the webbing extraction amount detection means. A webbing take-up force suppressing device has a drive means that operates based on the amount of the webbing, and a holding mechanism that is driven by the drive means and suppresses the biasing force of an elastic body acting on a take-up shaft when an occupant is wearing the webbing. (2) The driving means stores the maximum webbing rewinding position within a predetermined time after the webbing is pulled out when the passenger is wearing the webbing, and after the predetermined time elapses, the driving means stores the webbing maximum rewinding position corresponding to an appropriate slack amount. The webbing take-up force suppressing device according to claim 1, wherein the holding mechanism is driven at a position where the webbing is pulled out by a predetermined amount.