JPS6223660Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a webbing take-up device used in a seat belt device for protecting occupants in vehicle emergencies.

In the seat belt device, one end of the webbing for restraining an occupant is wound onto a retractor using a biasing force, so that the middle part of the webbing is placed around the occupant, and when the occupant releases the webbing, the webbing is retracted onto the retractor and placed inside the vehicle. Care is taken to avoid scattering.

In such a webbing retractor, the webbing retracting force is limited to a predetermined value or less in order to eliminate the feeling of pressure on the occupant under normal vehicle driving conditions. Slack is occurring. Therefore, even after the vehicle is in a collision state and the webbing is stopped from being unwound from the take-up device by the inertia lock mechanism, the occupant is not sufficiently restrained until the occupant moves in the direction of the collision and the slack is resolved. It has been pointed out.

For this reason, conventional webbing retractors have been capable of forcibly retracting the webbing onto the retracting shaft in the event of a vehicle emergency using the explosive force of explosives, and making it possible to bring the webbing into close contact with the occupant before the occupant moves due to inertia in the direction of the collision. A device has been proposed.

However, since this webbing take-up device uses gunpowder power as the driving force, the mechanism for properly transmitting this gunpowder power to the winding shaft is complicated, and it is difficult to adjust the gunpowder power, which may cause a fire. It also has

In consideration of the above facts, the present invention is a webbing retractor which has a simple structure and is capable of forcibly retracting the webbing onto the retracting shaft in the event of a vehicle emergency to reduce the slack between the occupant and the webbing. It is an object of the present invention to provide a highly safe webbing retractor.

The webbing take-up device according to the present invention locks one end of a pair of series-connected springs to the take-up shaft, and fixes the springs by a locking means at the connecting portion of the springs, so that only the first spring is engaged when the vehicle is normally running. The second spring's biasing force is applied to the winding shaft to reduce the feeling of pressure on the occupants when the vehicle is running, and in the event of a vehicle emergency, the acceleration sensor releases the locking means and the second spring's biasing force is also applied to the winding shaft to force it. The webbing is wound up to reduce slack between the occupant and the webbing.

Here, series connection means that the other end of the first spring and the second
This refers to a state in which both ends of the spring are locked to a ratchet wheel, and the ratchet wheel is normally rotatable. Further, the locking means is composed of a ratchet foil which is a connecting portion and a pawl that prevents rotation of the ratchet foil.
Furthermore, the acceleration sensor that releases the lock is
It refers to something that mechanically transmits rolling motion, such as a pendulum or a ball, or something that releases the above-mentioned blockage by electrically transmitting it.

As a prior art, Japanese Utility Model Application Publication No. 54-150230 discloses a device using two springs similarly to the present invention. That is, in this prior art, when a vehicle is in an emergency, a movable member moves in the axial direction of the winding shaft to engage the internal teeth of the movable member with a gear fixed to the winding shaft, and through the movable member, the spring is released. It is designed to transmit the biasing force to the winding shaft.

However, this prior art has the following problems.

When the movable member moves and the internal gear attempts to engage with the gear on the winding shaft, the internal gears rotate with each other, making it difficult for them to engage, resulting in uncertain operation.

Since the moving member needs to be moved in the axial direction of the winding shaft, extra space is required for movement.

In contrast, in the present invention, the two springs are always connected, so there is no such problem and the operation is safe and reliable.

Further, in the present invention, the movable member includes a pawl, but the pawl only needs to move by the amount that it engages with the teeth of the ratchet wheel. In the prior art,
Not only does it have an arm corresponding to the pole,
It also has a moving member moved by the arm. Therefore, an extra space is required for the movement of this moving member. Furthermore, in order to transmit the biasing force of the spring, the internal teeth and the gear of the take-up shaft must be engaged with each other deeply to some extent, and therefore the amount of movement becomes large. Since the amount of movement of the pawl can be small compared to this amount of movement, such problems can be alleviated. The device is simple, since other problems can be eliminated or reduced.

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, a webbing retractor 10 according to this embodiment has a frame 12 fixed to a vehicle body by mounting bolts 14. As shown in FIG.

From both sides of this frame 12 are a pair of leg plates 1.
6 and 18 extend parallel to each other and pivotally support the winding shaft 20. One end of an occupant restraining webbing 22 is wound around the winding shaft 20 in a layered manner. An end portion (not shown) of the webbing 22 serves as a restraint portion for the occupant. The winding shaft 20 also has a pair of ratchet foils 2 on both sides of the webbing 22.
4 is fixed thereto, and corresponds to a pole 26 that is pivotally supported on the leg plates 16 and 18. This pawl 26 is separated from the ratchet wheel 24 due to its own weight when the vehicle is normally running, but when the vehicle is in an emergency, it is pushed up by the pendulum 28, which is an acceleration sensor, and engages with the ratchet wheel 24, thereby controlling the webbing unwinding rotation of the winding shaft 20. It is designed to be stopped.

The pendulum 28, the pole 26 and the ratchet wheel 24 constitute an inertia lock mechanism.

A slit 32 is formed in the end 30 of the winding shaft protruding from the leg plate 18, and the inner end of the first mainspring spring 34 is inserted into the slit 32 and locked therein.

A small diameter shaft 36 is further coaxially connected to the winding shaft end 30, and a boss 4 of a ratchet wheel 38 is connected to the winding shaft end 30.
0 is pivoted. This ratchet foil 38
As shown in FIG. 3, the outer end of the first mainspring spring 34 is locked inside.

Furthermore, a slit 42 is formed in the boss portion 40 of the ratchet wheel 38, as shown in FIG. 2, and the inner end of the second mainspring spring 44 is locked therein. The outer end of the second mainspring spring 44 is secured to the inside of a dust cover 46 which also serves as a spring case and which is fixed to the leg plate 18.

Therefore, the first and second mainspring springs 34 and 44 are connected in series through the ratchet wheel 38, and both apply a biasing force to the winding shaft 20.
0 in the winding direction of the webbing 22. The second mainspring spring 44 is designed to have a significantly larger biasing force than the first mainspring spring 34.

The outer peripheral tooth surface of the ratchet wheel 38 is the pawl 48.
It corresponds to This pawl 48 is pivoted to the leg plate 18 by a pin 50, and one end thereof engages the ratchet wheel 38. This pole 48
and the ratchet wheel 38 constitute a locking means, which prevents the biasing force of the second mainspring spring 44 from being transmitted to the winding shaft 20. Only the biasing force of the mainspring spring 34 is applied to the winding shaft 20 to rotate the winding shaft 20 in the webbing winding direction. Therefore, the occupant wearing the webbing 22 receives only a weak biasing force from the first mainspring spring 34.

The other end of the pole 48 corresponds onto the top surface 54 of the pendulum 52. This pendulum 52 is vertically suspended from the leg plate 18 by a bracket 56, and when the vehicle is normally running, it is separated from or in slight contact with the other end of the pole 48, and in the event of a vehicle emergency, it tilts and moves the pole 48 around the pin 50. The pawl 48 is separated from the ratchet wheel 38 by rotating it. When the pawl 48 is separated from the ratchet wheel 38, the biasing force of the second mainspring spring 44 acts on the winding shaft 20.

Here, the pendulum 52 has a role as an acceleration sensor.

To explain the operation of this embodiment configured in this way, the occupant can unwind the webbing 22 from the take-up shaft 20 and put it on. When the vehicle is normally running, the pawl 48 is engaged with the ratchet wheel 38, so the webbing 22 can be attached to the webbing 22. Only the biasing force of the first mainspring spring 34 acts on the winding shaft 20, and the winding force of the first mainspring spring 34, which has a weak biasing force, is only transmitted via the webbing 22 to the occupant, so there is almost no impact. You will not feel any pressure and will not cause fatigue.

When the vehicle is in an emergency situation such as a collision, the pendulum 52 tilts to separate the pole 48 from the ratchet wheel 38, so that a large biasing force of the second mainspring spring 44 acts on the winding shaft 20, and this large winding force causes the webbing to By winding up the webbing 22, the webbing 22 can be brought into close contact with the passenger, thereby reducing the slack between the passenger and the webbing.

At the same time, the pendulum 28 engages the pawl 26 with the ratchet wheel 24, so that the webbing unwinding rotation of the take-up shaft 20 is stopped, and the occupant is tightly restrained, ensuring safety.

Next, FIG. 4 shows a second embodiment of the present invention, in which a detector 58 and a solenoid 60 are provided as acceleration sensors. This detector 58 is capable of electrically detecting the emergency state of the vehicle using an inertial body such as a pendulum or ball that rolls under acceleration, and transmits the electrical signal to the solenoid 60. A plunger 62 of a solenoid 60 is adapted to rotate the pole 48 about the pin 50.

Therefore, in this embodiment, as in the previous embodiment, it is possible to separate the pawl 48 from the ratchet wheel 38 in case of a vehicle emergency and apply the biasing force of the second mainspring spring 44 onto the winding shaft 20. Since the solenoid 60 is used, a large driving force for rotating the pole 48 can be obtained.

As explained above, the webbing retractor according to the present invention fixes the connecting portion of a pair of series-connected springs by a locking means, and this locking means can be unlocked by an acceleration sensor. This has the excellent effect of reliably reducing the slack between the occupant and the webbing, eliminating the need to use explosives, and eliminating the danger of fire and the like.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a first embodiment of the webbing retractor according to the present invention, FIG. 2 is a sectional view taken along the line of FIG. 1, FIG. 3 is a sectional view taken along the line of FIG. 1, and FIG. FIG. 2 is a sectional view corresponding to FIG. 2 according to a second embodiment of the present invention; 10... Webbing winding device, 12... Frame, 20... Winding shaft, 22... Webbing, 34
...First mainspring spring, 38...Ratchet foil, 44...Second mainspring spring, 48...Pole, 52...Pendulum, 58...Detector, 60...Solenoid.

Claims (1)

[Scope of utility model registration request] In a webbing retractor in which a take-up shaft for winding one end of the webbing is pivotally supported on a frame, one end of a first mainspring spring provided coaxially with the take-up shaft is locked to the take-up shaft, and the first mainspring spring is The other end of the spring is locked to a ratchet wheel that can rotate coaxially with the winding shaft, and one end of a second mainspring spring provided coaxially with the ratchet foil is locked to the ratchet wheel;
The other end of the second mainspring spring is locked to the frame, and the ratchet wheel is characterized by having a mechanism that normally prevents rotation by a pawl and releases the blocking using an acceleration sensor in case of a vehicle emergency. Webbing retractor.