JPH034598Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a webbing take-up device for use in a seat belt device for protecting an occupant in a vehicle emergency and for winding up webbing for restraining an occupant.

[Background Art] A webbing retractor is a device that is fixed to a part of the vehicle body and uses a biasing force to wind up the end of the webbing for occupant restraint onto a take-up shaft and store it there. Therefore, a lock mechanism is built in to prevent the webbing from unwinding.

Webbing retractors having this locking mechanism are broadly classified into automatic locking retractors (ALR) and emergency locking retractors. In the automatic lock type winding device, a lock ring and a friction plate are provided on the winding shaft, and a pole or a lock bar that engages with the lock ring is installed on the leg plate side. Therefore, if the occupant pulls out the webbing from the take-up device and puts it on, and then retracts the webbing even a little, the friction plate engages the lock bar with the lock ring, preventing the take-up shaft from rotating in the webbing unwinding direction. .

However, the conventional automatic lock type winding device has
There have been problems such as the locking mechanism being complicated and the control of the locking mechanism by the friction plate using frictional force being unstable.

[Purpose of the invention] The present invention has been made in view of the above circumstances, and its purpose is to provide an automatic lock type webbing retractor with a simple structure and reliable locking and releasing operations.

[Structure of the invention] In order to achieve the above object, the invention includes a take-up shaft for winding the occupant restraint webbing, a lock ring attached to the take-up shaft and rotating integrally with the take-up shaft,
a pawl that engages with the lock ring to prevent rotation of the take-up shaft in the webbing unwinding direction;
an arm whose one end is fixed to the pole; a cam which is attached integrally with the winding shaft and with which the other end of the arm can come into contact; winding diameter sensing means for separating the pole from the lock ring in a state where the webbing is wound up by a second winding amount formed on the cam; a first cam groove that the other end of the arm abuts to maintain the pole apart from the lock ring; and a third take-up amount formed in the cam and in which the webbing is less than the second take-up amount. The second cam groove, which the other end of the arm comes into contact with in the state in which the pawl is engaged with the lock ring, and the first cam groove and the second cam groove communicate with each other, and the webbing is connected to the second cam groove. The conventional friction plate is eliminated by incorporating a third cam groove into the winding device that moves the arm to the second cam groove by rotating the winding shaft in the webbing winding direction while the winding amount is being wound. It has been done.

[Embodiment of the invention] Fig. 1 shows a webbing retractor 1 according to the invention.
FIG. In this webbing retractor 10, a frame 12 is fixed to a vehicle body 16 with mounting bolts 14, and a pair of leg plates 18 and 20 protrude from both sides of the frame 12.

A webbing take-up shaft 22 is pivotally supported between these leg plates 18 and 20, and the take-up shaft 22 winds one end of the occupant restraint webbing 24 in a layered manner. A tongue plate (not shown) is attached to the other end of the webbing 24. Therefore, the occupants on the seats must use a buckle device (not shown) installed upright from the vehicle floor.
By inserting the tongue plate into the webbing, the webbing can be attached.

A mainspring spring 26 is wound around the end of the winding shaft 22 that protrudes from the leg plate 20.
6 is covered by a spring case 28. The mainspring spring 26 biases the take-up shaft 22 in the webbing take-up direction.

Furthermore, lock rings 30 and 32 are fixed to both sides of the webbing of the winding shaft 22 so as to rotate together with the winding shaft 22. Lock ring 30,3
As can be seen from FIG. 2, a plurality of ratchet teeth 34, 36 are carved on the outer periphery of the lock bar 2, and each ratchet tooth 34, 36 has a claw portion 40, 42 of the lock bar 38.
is compatible. The lock bar 38 is rotatably supported between the leg plates 18 and 20 substantially parallel to the winding shaft 22, and one end thereof projects beyond the leg plate 18.

One end of the winding shaft 22 protrudes beyond the leg plate 18,
A cylindrical cam 44 is attached to its tip. As shown in FIG. 3, two annular grooves 46 and 48 are formed on the outer surface of the cam 44, and an inclined groove 50 connecting the annular grooves 46 and 48 is further provided. As shown in FIG. 3, when the cam 44 rotates in the webbing winding direction when the tip of the arm 52 is in contact with the annular groove 48, the tip of the arm 52 is inserted into the inclined groove 50. An upright surface 48B is formed to allow movement. This rising surface 4
8B is inclined with respect to the axial direction of the cam 44 and is formed to be smoothly continuous with one rising surface 50A of the inclined groove 50. The tip of the arm 52 fits into the annular groove 48 and is lightly pressed against it by the biasing force of the tension coil spring 54, as shown in FIG.

The other end of arm 52 is secured to one end of lock bar 38, as shown in FIG. For this reason,
The lock bar 38 is adapted to rotate together with the arm 52 when the arm 52 is rotated by the cam 44.

The annular groove 46 on the outer surface of the cam is formed deeper than the annular groove 48. Therefore, when the tip of the arm 52 is in the annular groove 48, the lock bar 38 is in a non-engaging position with the lock rings 30, 32 (FIGS. 1 and 2), but when the arm 52 moves into the annular groove 46, the arm 52 and lock bar 38 pivot counterclockwise in FIG. However, in this embodiment, as can be seen from FIG. 4, the pawls 40, 42 of the lock bar 38 do not contact the bottoms of the ratchet teeth 34, 36 of the lock ring, but are stopped at a position with a slight gap. This is to reduce noise generated between the lock wheels 30, 32 and the lock bar 38 as much as possible.

The inclined groove 50 is formed to diagonally connect the annular grooves 46 and 48, and is dimensioned to be slightly deeper than the annular grooves 46 and 48 and shallower than the annular groove 46. Therefore, while the take-up shaft 22 and the cam 44 rotate in the webbing drawing direction (direction A in FIG. 3), the arm 52 remains in the annular groove 48. However, when the cam 44 rotates in the webbing winding direction (direction B in FIG. 3), the arm 52 enters the inclined groove 50 at the branching point of the groove, and finally moves to the annular groove 46. Arm 5
2 uses a flexible material so that it can follow the axial movement of the cam 44. The cam 44 and arm 52 protruding from the leg plate 18 are covered by a cover 56 (FIG. 1).
coated with

As shown in FIG. 1, a winding diameter sensing arm 58 is attached to approximately the middle of the lock bar 38, and the tip of the winding diameter sensing arm 58 is in contact with the outer surface of the webbing on the winding shaft 22. The winding diameter sensing arm 58 maintains the lock bar 38 in the disengaged position of the lock wheels 30, 32 while the winding diameter of the webbing 24 is large, as seen in FIG. Arm 52, lock bar 3
8 and the winding diameter sensing arm 58 are integrated, the tension coil spring 54 connected to the arm 52 constantly biases the winding diameter sensing arm 58 in the direction of contact with the webbing 24. Further, if the winding diameter sensing arm 58 is made of a spring material, it can be brought into pressure contact with the webbing 24 independently.

The webbing retractor of this embodiment configured as described above operates as follows. When the occupant on the seat first pulls the tongue plate, the webbing 24 is pulled out from the take-up shaft 22 since the lock wheels 30, 32 are not locked as shown in FIG. During this time, the winding diameter sensing arm 58
8, and the arm 52 remains fitted into the annular groove 48 of the cam 44.

When the occupant wears the webbing, the winding diameter of the webbing 24 becomes smaller, so the blocking action of the winding diameter sensing arm 58 against the lock bar 38 is released. However, since the arm 52 is still within the annular groove 48,
The lock bar 38 is out of engagement with the lock wheels 30 and 32.

Next, after putting on the webbing, the occupant changes his or her driving position slightly, reduces the abdomen due to breathing, etc., and then attaches the webbing 2.
4 into the winding device, the cam 44 rotates in the opposite direction to that described above (direction B in FIG. 3), and the tip of the arm 52 comes into contact with the rising surface 48B. Therefore, the tip of the arm 52 is connected to the upright surface 4 of the cam 44.
8B, it is guided by the inclined groove 50 and moves through the inclined groove 50 to the annular groove 46. At this time, the arm 52 pivots not only in the axial direction but also in the counterclockwise direction in FIG. 2 and moves to the position shown in FIG. 4. Together with the arm 52, the lock bar 38 also pivots in the direction of engagement with the lock ring 30, and each pawl 40, 42 engages with the bottom of each ratchet tooth 34, 36 to the extent that it does not contact.

Therefore, rotation of the take-up shaft 22 in the webbing unwinding direction is prevented by the lock bar 38.

Furthermore, as can be seen from the shape of the ratchet teeth 34 and 36 of the lock ring, the webbing 24 is attached to the winding shaft 22.
It is possible to wind it up. Therefore, when the webbing 24 is attached to a passenger or luggage, a reliable restraining force can be obtained by the automatic locking action.

When the webbing unwinding stop of the winding device is canceled, the tongue plate is removed from the buckle and the entire amount of the webbing 2 is wound onto the winding shaft 22. When the webbing winding diameter on the winding shaft 22 increases, the winding diameter sensing arm 58 rotates the lock bar 38 and the arm 52 clockwise in FIG.
0,42 are removed from the ratchet teeth 34,36. Furthermore, the arm 52 that has separated from the annular groove 46 returns to the annular groove 48 side due to its own flexibility, returning to the state shown in FIG. 2 again. As shown in FIG. 3, since the proximal shaft diameter d ₂ of the cam 44 is larger than the distal shaft diameter d ₁ , the arm 52 separated from the annular groove 46 collides with the surface 48A and forms an annular shape. It fits securely into the groove 48. In this embodiment, since the pawls 40, 42 and the ratchet teeth 34, 36 are not in direct contact when engaged, it is possible to minimize the noise generated between them when the webbing 24 is completely wound up. Further, if a plurality of inclined grooves 50 are formed in the cam 44, the arm 52 can be moved from the annular groove 48 to the annular groove 46 by a slight rotation of the cam 44.

[Effects of the invention] As described above, the present invention provides a reliable webbing retractor with a simple structure and automatic locking operation.

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional view of the webbing retractor according to the present invention, Fig. 2 is a sectional view along the line shown in Fig. 1 with the leg plate removed, Fig. 3 is a perspective view of the cam, and Fig. 4 is in the locked state. FIG. 2 is a sectional view similar to FIG. 2 taken along the line of FIG. 1 in FIG. 10... Webbing winding device, 22... Winding shaft, 24... Webbing, 30... Lock ring, 3
2... Lock ring, 38... Lock bar (pole),
44... cam, 46... annular groove (second cam groove),
48... Annular groove (first cam groove), 50... Inclined groove (third cam groove), 52... Arm, 58... Winding diameter sensing arm (winding diameter sensing means).

Claims (1)

[Scope of utility model registration request] A take-up shaft for winding up occupant restraint webbing, a lock ring attached to the take-up shaft and rotating integrally with the take-up shaft, and rotation of the take-up shaft in the webbing unwinding direction by engaging with the lock ring. an arm that has one end fixed to the pole, a cam that is integrally attached to the take-up shaft and that the other end of the arm can come into contact with, and a take-up shaft that is attached to the pole. winding diameter sensing means for separating the pole from the lock ring when the webbing is taken up at a first winding amount; a first cam groove in which the other end of the arm abuts to maintain the pawl away from the lock ring when the arm is taken up; a second cam groove with which the other end of the arm abuts to maintain the pawl in engagement with the lock ring when the pole is wound up by a winding amount of 3; a first cam groove and a second cam groove; a third cam groove that communicates with the webbing and moves the arm to the second cam groove by rotating the take-up shaft in the webbing take-up direction in a state where the webbing is taken up by a second take-up amount. .