JPS6218526Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a webbing take-up force reduction device that is used in a seat belt device for protecting an occupant in a vehicle emergency and reduces the take-up force of the webbing for restraining an occupant onto a take-up shaft.

In a seat belt device, the end of the webbing for restraining an occupant is wound in layers onto a take-up shaft, and by rotating this take-up shaft in the webbing take-up direction with the biasing force of a mainspring spring, the middle part of the webbing is attached to the passenger after the webbing is attached. In addition, after the webbing is removed, the remaining part of the webbing is wound onto the take-up shaft to prevent the webbing from being scattered inside the vehicle.

However, the tension of the webbing generated by the power spring acts on the occupant as a feeling of pressure, which causes fatigue in the occupant. For this reason, it is desirable to reduce the webbing winding force as much as possible, but in order to reliably wind the webbing onto the winding shaft after the webbing is released, a biasing force of a certain value or more is required. In response to this, various webbing winding force reduction devices have been proposed in the past,
These devices have problems such as a complex structure and the reduced state of the webbing winding force being released when the occupant moves significantly after putting on the webbing. Furthermore, with the conventional webbing winding force reduction device, there is a problem that when unwinding the webbing during normal use when the winding force is not reduced, the unwinding feels heavy and the operation feeling is poor.

Taking the above facts into consideration, the present invention has a simple structure that reliably creates a webbing tension reduction state after the occupant wears the webbing, and also maintains the tension reduction range even if the occupant makes large movements indoors while the vehicle is running. It is an object of the present invention to provide a webbing take-up force reducing device that does not cause the above problem, has a light unwinding feeling during normal use, and has a good operational feeling.

The webbing take-up force reduction device according to the present invention is provided with a transmission gear to which rotation of a take-up shaft for winding up the occupant restraint webbing with a biasing force is transmitted,
A blocking gear for blocking rotation of the transmitting gear is disposed opposite to the transmitting gear. This blocking gear has a semicircular shape as a whole, and an internal gear for meshing with the transmission gear is formed on the inner circumference,
The outer peripheral portion has a shape that follows the inner peripheral surface of the cylindrical member. A long hole is formed on one side of the blocking gear, and a fixing pin for stopping the movement passes through the long hole. A spring is provided on the opposite side of the blocking gear, and the elongated hole end is arranged in a direction that separates the blocking gear from the transmission gear, and on a side where the fixing pin blocks movement of the blocking gear during winding. bias in the direction of contact. A rocker arm is disposed on the outer peripheral side of the blocking gear, and the rocker arm is rotated by the action of a solenoid that is energized by engagement of the buckle device of the occupant restraint webbing, and the rocker arm is rotated by the action of a solenoid that is energized by engagement of the buckle device of the occupant restraint webbing. The outer circumference of the transmission gear is pressed to mesh the internal gear on the inner circumference with the transmission gear.

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

1 and 2 show a seat belt retractor 10 to which the present invention is applied, in which a frame 12 is fixed to a vehicle body 16 with mounting bolts 14. A pair of leg plates 1 are attached from both sides of the frame 12.
8 and 20 extend parallel to each other, and a winding shaft 22 is pivotally supported.

This winding shaft 22 has a webbing 24 for restraining an occupant.
One end is wound up in layers. A spring spring winding device 26 is provided between the winding shaft 22 and the leg plate 20, and biases the winding shaft 22 in the webbing winding direction (direction of arrow A in FIG. 2). The other end (not shown) of the webbing 24 is fixed to the vehicle body, and the passenger holds the middle part of the webbing 24 against the urging force of the mainspring spring winding device 26 and attaches it to the winding shaft 24.
It can be unrolled and installed.

On the other hand, a pinion 28 is fixed to the end of the winding shaft 22 projecting from the leg plate 18 so as to rotate together with the winding shaft 22. This pinion 28 meshes with a transmission gear 32 supported by a shaft 30 protruding from the leg plate 18. The transmission gear 32 has a larger diameter than the pinion 28, so that the rotation speed of the pinion 28, that is, the rotation speed of the winding shaft 22 is reduced.

A blocking gear 34 corresponds to this transmission gear 32 . This blocking gear 34 has a semicircular shape as shown in FIG.
The housing 36 is supported by the inner peripheral surface of the housing 36 attached to the housing 8 . Further, a long hole 38 is bored in one side of this blocking gear 34, and a pin 40 as a stop means protruding from the leg plate 18 is inserted into this long hole 38.
It penetrates inside. A tension coil spring 42 is connected to the housing 36 at the opposite end of the elongated hole 38.
is interposed and urged in the direction of arrow B, and this urging force causes the internal gear 44 of the blocking gear 34 to separate from the transmission gear 32, and the blocking gear 34 is urged to one side. The end of the elongated hole 38 comes into contact with the pin 40 and is stopped. Further, a stepped portion 46 is formed on the outer periphery of the blocking gear 34, and corresponds to the pawl 48. This pawl 48 is pivotally supported by a pin 50 to one end of a rocker arm 52 which is pivotally supported to the leg plate 18, and the other end of this rocker arm 52 is adapted to be sucked by a solenoid 54. This solenoid 54 is connected in series to a buckle switch 56 and a vehicle power source 58 as shown in FIG. It is becoming more and more like this. This causes the rocker arm 52 to bring the pawl 48 into contact with the stepped portion 46 of the blocking gear 34.
Further, the blocking gear 34 is moved to the second position around the pin 40.
The internal gear 44 rotates counterclockwise in the figure.
is adapted to mesh with the transmission gear 32 against the biasing force of the tension coil spring 42. Paul 4
A tension coil spring 60 is interposed between the roller 8 and the rocker arm 52, so that the pawl 48 can rotate relative to the rocker arm 52 when a large external force is applied to the pawl 48.

Here, the pawl 48, the rocker arm 52, and the solenoid 54 serve as driving means for meshing the blocking gear 34 with the transmission gear 32.

A pair of ratchet foils 62 are fixed to the winding shaft 22 of the webbing 24, and the leg plate 1
8 and 20. This pole 64 is placed on a pendulum 66, and this pendulum 66 is suspended from a bracket 68 fixed to the leg plates 18, 20. This pawl 64 is separated from the ratchet wheel 62 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 swinging pendulum 66 and engages with the ratchet wheel 62, thereby unwinding the webbing from the ratchet wheel 62 and the winding shaft 22. It is designed to stop rotation.

The operation of this embodiment configured in this way will be explained. After getting on the vehicle, the occupant unwinds the webbing 24 from the take-up shaft 22 and attaches the intermediate portion of the webbing 24 to put on the seat belt. In this case webbing 2
4 is engaged to attach the webbing. When the buckle device is engaged, the buckle switch 56 shown in FIG. Rotate around pin 50.

This causes the pawl 48 to rotate the blocking gear 34 around the pin 40 and engage it with the transmission gear 32. Here, the blocking gear 34 is prevented from moving in the webbing winding direction (in the direction of arrow B) because one end of its elongated hole 38 is in contact with the pin 40, and is therefore meshed with the blocking gear 34. The transmission gear 32 and pinion 28 are similarly prevented from rotating, and the webbing winding rotation of the winding shaft 22 is stopped. As a result, the biasing force of the mainspring spring winding device 26 does not act on the occupant wearing the webbing 24, so that the webbing winding force is reduced and the occupant can enjoy a comfortable riding condition.
In addition, when the passenger puts on the webbing 24, the webbing 24 is pulled out a little longer than the actual length of the webbing. The webbing winding tension can be reduced without excessively restraining the occupant, and without creating a large gap between the webbing 24 and the occupant.

When an occupant changes his or her driving posture while the vehicle is running, the webbing 24 is unwound from the take-up shaft 22 in accordance with the occupant's behavior. As the winding shaft 22 rotates to unwind the webbing, the pinion 28 and the transmission gear 32 rotate, the blocking gear 34 rotates in the webbing unwinding direction, and the end of the elongated hole 38 separates from the pin 40. After that, when the occupant returns to the normal riding condition, the unwound webbing 24 is wound onto the take-up shaft 22 again, so that the blocking gear 34 is moved in the webbing take-up direction (in the direction of arrow B) by the biasing force of the tension coil spring 42. ), and the end of the elongated hole 38 is connected to the pin 4.
0 and stops. As a result, the blocking gear 34 returns to the meshing position where it meshes with the transmission gear 32 again, and the winding force of the webbing 24 is reduced.

In this way, when the passenger moves indoors, the elongated hole 3
The occupant can maintain the winding force reduction state by an amount equivalent to the length of 8, and the blocking gear 34 transmits the rotation of the winding shaft at a reduced speed, so that it can sufficiently cope with normal indoor behavior. I can do it.

If the vehicle is in an emergency situation at the time of a collision, the pendulum 66 is activated and the pawl 64 engages with the ratchet wheel 62 to stop the unwinding rotation of the webbing 24, so the occupant is securely restrained by the webbing 24 and safe. is guaranteed.

Also, the buckle device is engaged and the solenoid 54
Before the webbing is excited, that is, when unwinding the webbing during normal use when the winding force is not reduced, the blocking gear 34 with the elongated hole is connected to the winding shaft 22.
It is spaced apart from the side pinion 28 and the transmission gear 32, and therefore the winding shaft 22 for unwinding the webbing
The number of gears that rotate with the rotation is small, and the unwinding feeling is light and the operation feeling is good.

On the other hand, there is a conventional device that exists in the U.S.
The device described in Japanese Patent No. 166619 has a large number of gears meshing with the gears attached to the winding shaft even during normal operation, resulting in a heavy unwinding feeling. Also, JP-A-54-33424
In the device described in the publication, during normal use, the internal gear attached to the winding shaft must rotate while meshing with the external gear, and furthermore, the internal gear is connected to a disc clutch with a long hole. Let's take Etsuto around.
Therefore, the feeling of unwinding the webbing becomes heavy. Furthermore, in the device described in JP-A-56-76964 (Figs. 6 and 7), during normal use, the winding shaft cannot rotate against the frictional force with the friction plate with elongated holes. It has to be sticky, and the feeling of unwinding is heavy.

As described above, the fundamental reason why the conventional device has a structure in which the unwinding feeling during normal operation is heavier than that of the present invention is that a member having a long hole is provided on the winding shaft side. In the present invention, the blocking gear with the elongated hole is placed apart from the winding shaft, so the number of gears rotating together with the winding shaft can be reduced, and the unwinding feeling can be reduced.

As explained above, the webbing take-up force reduction device according to the present invention meshes the blocking gear with the transmission gear after the occupant wears the webbing, and prevents the blocking gear from moving in the webbing take-up direction from this meshing position. Therefore, it has an excellent effect of being able to reliably form a webbing winding force reduced state over a wide range with a simple structure. Further, during normal use, the blocking gear is arranged apart from the gear on the winding shaft side, so that the webbing can be unwound and the feeling of unwinding can be lightened and the operation feeling can be improved.

[Brief explanation of the drawing]

FIG. 1 is a front view showing an embodiment of the webbing take-up force reducing device according to the present invention, FIG. 2 is a left side view of FIG. 1, and FIG. 3 is a circuit diagram including a buckle switch. 22... Winding shaft, 24... Webbing, 26...
...Spring spring winding device, 32...Transmission gear,
34... Blocking gear, 44... Internal gear, 48...
...Poll, 54...Solenoid, 56...Block switch.

Claims (1)

[Scope of utility model registration request] A transmission gear is provided to which the rotation of a take-up shaft for winding up the occupant restraint webbing with a biasing force is transmitted, and a blocking gear is provided opposite to the transmission gear to prevent rotation of the transmission gear. is arranged, this blocking gear has a semicircular shape as a whole, and an internal gear for meshing with the transmission gear is formed on the inner peripheral part,
The outer peripheral part is shaped to follow the inner peripheral surface of the cylindrical member, and a long hole is formed on one side of the blocking gear, and a fixing pin for stopping the movement passes through the long hole, and the opposite side is formed with a long hole. A spring is provided on the side and urges the blocking gear in a direction that separates the blocking gear from the transmission gear and in a direction that the fixing pin abuts against the end of the long hole on the side that prevents movement of the blocking gear during winding. A rocker arm is disposed on the outer circumferential side of the blocking gear, and the rocker arm is rotated by the action of a solenoid that is energized by engagement of the buckle device of the occupant restraint webbing, so that the blocking gear A webbing take-up force reducing device characterized by pressing an outer circumferential portion of a gear to engage an internal gear on an inner circumferential portion with the transmission gear.