JPS609088Y2 - seat belt retractor - Google Patents

Description

[Detailed description of the invention] The present invention relates to a seatbelt retractor that winds up and stores an occupant protection seatbelt using a biasing force, and is particularly designed to reduce the feeling of pressure exerted on the occupant while wearing the seatbelt. The present invention relates to a seat belt retractor.

A seatbelt retractor has been proposed to reduce the pressure felt by the seatbelt retractor on the occupant while the seatbelt is being worn. By engaging the bowl with a ratchet wheel provided at this connecting portion and applying only the biasing force of one winding spring to the seat belt, the feeling of pressure on the occupant is reduced.

However, this seat belt retractor has only one retracting shaft.
When the seat belt is rotated in the take-up direction, the engagement between the bowl and the ratchet wheel is released, so if the seat belt is reeled in by a length equivalent to one or more revolutions of the take-up shaft, the seat belt is retracted. A large winding force is applied to the winding.

Therefore, in some cases, the reduced winding force may be canceled by simply winding up the excess amount when the seat belt is fastened, and the seat belt can be unrolled and retracted using the reduced winding force. There are extremely few areas where seatbelt winding force can be reduced, that is, the comfort zone, and for this reason, it has not been possible to reliably apply the seatbelt winding force reduction range to the unwinding and winding operations of the occupant during normal driving.

Taking the above facts into consideration, the purpose of the present invention is to provide a seat belt retractor that has a large comfort zone and can provide an extremely comfortable wearing condition, and has an appropriate play angle between the cam wheel and the control gear wheel. is provided, and when the seat belt is wound up, a comfort zone is secured for a length corresponding to this play angle and the rotation angle until the cam protrusion of the cam foil comes into contact with the bowl that engages with the latch gear in the middle part of the spring. It looks like this.

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

1 to 8 show a first embodiment of the present invention, in which a winding shaft 12 is pivotally supported in a housing 10 of a seat belt winding device, and an end portion of a seat belt 14 is supported by a winding shaft 12. It is wound up in layers (in the direction of arrow A) by the biasing force of a mainspring spring (not shown).

A tongue plate (not shown) is attached to the other end of the seat belt 14, and when the occupant wears the seat belt, the passenger engages the tongue plate with a buckle device (not shown) while unwinding the seat belt from the winding shaft 12. The seatbelt 14 can be attached to the occupant.

Note that a pair of ratchet wheels 16 are provided on the winding shaft 14.
is fixed to the winding shaft 12, and the unwinding rotation of the winding shaft 12 is stopped in the event of a vehicle emergency by the operation of an inertia lock mechanism (not shown), and the occupant is securely restrained by the seat belt 14.

A two-sided interior 18 and a narrow diameter portion 20 are formed at one end of the winding shaft 12 and protrude from the end of the housing 10 .

A latch gear wheel 22 is rotatably supported on this narrow diameter portion 20, and a first mainspring spring 26 is attached between this latch gear wheel 22 and a spring cup 24 attached to the housing 10. .

A shaft piece 2 is attached to the two-sided protruding portion 18 of the winding shaft 12.
8 is inserted into the rectangular hole and rotated together with the winding shaft 12, and this shaft piece 28
A second mainspring spring 30, which has a weaker biasing force than the first mainspring spring 26, is installed between the latch gear wheel 22 and the latch gear wheel 22.

Therefore, the winding shaft 12 is connected to the housing 10 by the first
, the second mainspring springs 26 and 30 are connected in series to receive the winding force of the seat belt 14, and when the rotation of the latch gear wheel 22 is stopped, the second mainspring spring 30 is connected in series. Only the winding force is the winding shaft 12
The winding force applied to the seat belt is reduced.

Next, a control gear wheel 32 is rotatably supported on the shaft piece 28, and both are connected by friction means.

That is, the shaft piece 28 has a protrusion 34 protruding from its outer periphery, and the other end of a leaf spring 36 whose one end is attached to the protrusion 34 is pressed against the inner circumference of the control gear wheel 32, thereby connecting the control gear wheel 32 and the shaft piece 28. It is designed to bring into frictional contact with.

Therefore, both rotate as one unit until they receive a predetermined resistance force.

It is of course possible to provide an elastic protrusion formed integrally with the shaft piece 28 instead of the leaf spring 36 here.

A friction plate 38 and a cam wheel 40 are pivotally supported on the outer periphery of the control gear wheel 32.

This friction plate 38 has a V-shaped leaf spring 42 whose tip is in contact with the outer periphery of the control gear wheel, so that the rotational force of the control gear wheel 32 is transmitted by frictional force.

This friction plate 38 is formed with a pair of bowl push-up projections 44, 46 and a bowl locking recess 48 formed between these projections.

The push-up protrusions 44 and 46 and the locking recess 48 are used to control a bowl 52 that is pivotally supported on the housing 10 via a side cover 50.

That is, the tooth tips of the bowl 52 are urged in the direction of the friction plate 38 by the urging force of the torsion coil spring 54, and when the bowl 52 is pushed up onto the bowl push-up protrusion 44 or 46 (see FIG. 4), the latch gear wheel The latch gear wheel 22 is spaced apart from the latch gear 22 to enable rotation of the latch gear wheel 22.

However, when the bowl falls into the locking recess 48, it engages with the latch gear of the latch gear wheel 22 and prevents the latch gear wheel 22 from rotating in the seat belt winding direction (in the direction of arrow A) as shown in FIG. It looks like this.

The friction plate 38 has a protrusion 39 provided on the opposite side of the bowl locking recess 48 that comes into contact with a pair of stoppers 51A and 51B provided on the side cover 50, so that the bowl push-up protrusion 44 or 46 comes into contact with the bowl 52. It is rotatable from the state shown in FIG. 4 to the state shown in FIG.

On the other hand, a protrusion 56 protrudes toward the axial direction of the cam wheel 40 that is pivotally supported by the control gear wheel 32, and corresponds to a protrusion 58 that protrudes from the control gear wheel 32 in the radially expanding direction. 58 provides an angle of play of about 360 degrees between the cam wheel 40 and the control gear wheel 32.

This angle of play can be varied by suitably adjusting the arrangement and number of projections 56,58.

Further, this cam foil 40 has a triangular push-up protrusion 60 protruding from its outer periphery, and when rotated in the seat belt winding direction, the bowl is pushed up as shown in FIG. When the seatbelt is rotated in the unwinding direction, it receives the rotational force from the control gear wheel 32 via the protrusions 56 and 58 so that it comes into contact with the bowl 52 and stops. has become,
For this purpose, the control gear wheel 32 is adapted to slide on the shaft piece 28.

The housing 10 is fixed to an appropriate position on the vehicle using mounting bolts (not shown).

Next, the operation of the first embodiment will be described. After the occupant is seated, the seat belt 14 is unwound from the winding shaft 12 against the biasing force of the mainspring spring 26 and 30 in order to put on the seat belt 14.

This unwinding rotation causes the leaf spring 36 of the shaft piece 28 to rotate the control gear wheel 32 in the seat belt unwinding direction, and the friction plate 38 and cam wheel 40 are also rotated in the same direction.

However, the cam wheel 40 slides on the control gear wheel 32 with the push-up protrusion 60 in contact with the bowl 52, and the friction plate 38
similarly slides on the control gear wheel 32 with the protrusion 34 in contact with the bowl 52.

Furthermore, as the occupant continues to put on the seatbelt (that is, unwind the seatbelt), the mainspring spring 26,30 is gradually wound up more strongly, so its biasing force increases, and finally the latch gear wheel 22 twists to overcome the biasing force of the coil spring 54. As the bowl 52 is rotated against this, the friction plate 38 rotates as shown in FIG. 4, and the bowl 52 rides on the projection 34 and stops.

After that, the occupant attaches the tongue plate (not shown) to the buckle device to complete the seatbelt attachment operation, but normally the seatbelt is unwound a little longer than the length required for the occupant to attach it, so when attaching the seatbelt, it is necessary to A belt winding action occurs for a corresponding length.

Therefore, rotation of the winding shaft 12 in the seat belt winding direction causes the shaft piece 28 to rotate clockwise in FIG. 8, and the leaf spring 36 of the shaft piece rotates the control gear wheel 32 in the same direction due to frictional force. The friction plate 38 is rotated in the seat belt winding direction by the frictional force with the control gear wheel 32, and the bowl 52 falls into the ratchet locking recess 48 as shown in FIG. 5 and engages with the latch gear wheel 22.

As a result, the biasing force of the first mainspring spring 26 is not transmitted to the winding shaft 12, and only the biasing force of the second mainspring spring 30, which has a weak biasing force, is transmitted to the winding shaft 12.
As a result, the winding force applied to the seat belt 14 is reduced, and the feeling of pressure on the occupant is eliminated.

In this winding force reduction range, that is, the comfort zone, when the occupant winds up the seat belt onto the winding shaft 12, the winding rotational force of the winding shaft is applied to the shaft piece 28.
After the control gear wheel 32 rotates about 360 degrees clockwise in FIG. The push-up protrusion 60 is rotated clockwise and the bowl 52 is rotated as shown in FIG.
It is maintained until it is pushed up.

In other words, the comfort zone is always maintained within the winding operation range corresponding to two revolutions of the winding shaft 12, so that it is possible to sufficiently cope with the movement of the body of the occupant during normal driving.

Conventionally, the cam foil only had a comfort zone where it could be rotated approximately 360 degrees in the winding direction, so the comfort zone was canceled by the slightest movement of the occupant, causing discomfort to the occupant.

Further, when the occupant unwinds the seat belt, the comfort zone will not be released until the second mainspring spring 30 is in close contact with the seat belt.

Next, when the occupant releases the seat belt, the control gear wheel 32
rotates the cam wheel 40 in the seat belt winding direction, and after the winding shaft 12 rotates twice in the winding direction, the cam wheel 40 pushes up the bowl 52 and finally the latch gear wheel 22 is moved as shown in FIG. This will cause a separation.

As a result, the bowl 52 rides on the ratchet push-up protrusion 46 of the friction plate 38, and the latch gear wheel 22 is free to rotate, so that the winding force of the first mainspring spring 26 is transmitted to the winding shaft 12, and the normal strong winding force is transmitted to the winding shaft 12. The seat belt 14 can be completely wound up with the winding force.

Next, FIG. 9 shows a shaft piece 62 and a control gear wheel 64 according to a second embodiment of the present invention, and a transmission means between the two is shown in a different embodiment from the above.

That is, the compression coil spring 66 is connected to the shaft piece 62.
The small bowl 68 is projected in the radially expanding direction due to the biasing force, and meshes with an internally toothed ratchet gear 70 carved in the inner diameter portion of the control gear wheel 64.

Therefore, in this embodiment as well, the control gear wheel 64 is rotated together with the take-up shaft 12 when it rotates in the seat belt unwinding direction, but after the push-up projection 60 of the cam wheel 40 comes into contact with the bowl 52, the control gear wheel 64 rotates with the winding shaft 12. When the winding shaft 12 rotates in the seat belt winding direction, the small bowl 68 and the internally toothed ratchet gear 70 engage with each other to cause the control gear wheel 32 to slide. is forcibly rotated in the seat belt retracting direction, making it possible to obtain the same effect as in the previous embodiment.

As explained above, the seatbelt retractor according to the present invention transmits the retracting rotational force of the seatbelt retractor shaft to the control gear wheel, and retracts the seatbelt with a predetermined resistance force or more when the seatbelt retractor shaft unwinds and rotates. The shaft and the control gear wheel are rotated relative to each other, and the control gear wheel and the cam wheel are provided with an angle of play, which expands the comfort zone of the seatbelt and allows the occupant to wear the seatbelt comfortably. have an effect.

[Brief explanation of the drawing]

Fig. 1 is an exploded perspective view showing a first embodiment of the seat belt retractor according to the present invention, Fig. 2 is a sectional view of Fig. 1, Fig. 3 is a sectional view taken along the line 4 is a sectional view taken along the line IV-IV in FIG. 2, FIGS. 5 to 7 are operational diagrams in FIG. FIG. 7 is a side view showing the relationship between the shaft piece and the control gear wheel according to the second embodiment of the invention. 12... Winding shaft, 14... Seat belt, 22... Latch gear wheel, 26...
...First mainspring spring, 28...Shaft piece, 30...Second mainspring spring, 36.
...Plate spring, 38...Friction plate, 40...
...Cam foil, 52...Cam foil, 5
6.58... Protrusion, 60... Push-up protrusion, 62... Shaft piece, 64...
Control gear wheel, 68...Small bowl, 70...
...Internal tooth ratchet gear.

Claims (1)

[Scope of utility model registration request] A first spring and a second spring having a weaker biasing force than the first spring are connected in series and connected to the seatbelt winding shaft to apply a seatbelt winding force, and a spring means is provided at the connection portion between the two springs. ratchet means for engaging the bowl with the latch gear to prevent the urging force of the first spring from being applied to the take-up shaft; A control gear wheel is connected with a predetermined play angle between the control gear wheel and the control gear wheel, which can rotate relative to the seatbelt take-up shaft with a predetermined resistance force or more during the unwinding rotation of the seatbelt. a cam foil that comes into contact with the bowl to generate the predetermined resistance force and pushes up the bowl to separate the bowl from the latch gear when the seat belt is wound up and rotated.