JPS5919862B2 - Seat belt retractor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a seat belt retractor for automatically retracting a seat belt, and more particularly to a mechanism for controlling the retracting force.

The mainspring spring in a conventional winding device such as the IJ l-actor has its central end fixed to the winding shaft of the winding device, and its outer peripheral end fixed to the main body of the winding device via a storage box such as a barrel, and is used to wind the seat belt. By unwinding from the take-up device,
It is common to tighten the mainspring spring to increase the winding force of the seat belt.

However, in conventional systems like this, the mainspring spring is tightened when the seat belt is unwound, so the retracting force usually increases as the seat belt is unwound. Belt systems that are used to attach the vehicle have the disadvantage that the winding force is too strong when the vehicle is attached, increasing the feeling of restraint on the occupant and making the rider feel uncomfortable when wearing the vehicle.

In particular, when a lap belt or a shoulder belt is made of continuous webbing and a winding device is installed on the shoulder belt side, the amount of belt winding by the winding device increases further.

Therefore, if the strength of the spiral spring is set to be appropriate when the occupant is restrained, the winding force of the belt during storage will be insufficient.

On the other hand, if the belt winding force at the time of storage is set sufficiently, the restraint force at the time of restraining the occupant becomes too strong, resulting in extremely poor usability.

SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to provide a seatbelt retractor that has a sufficient retracting force when the seatbelt is stored, and at the same time has a weak retracting force when the occupant is restrained.

In order to achieve this purpose, the present invention includes a first spring section that applies a winding force to a take-up reel that winds up the seat belt, and a second spring section that has a weaker urging force than the first spring section in the same direction as the first spring section. a second spring portion, a clutch means for intermittent transmission of the biasing force of the second spring portion to the take-up reel, and a signal from a switch means for detecting whether or not a seat belt is fastened, and the clutch means is engaged or engaged in response to a signal from a switch means for detecting whether or not a seat belt is fastened. Equipped with an electric actuator.

An embodiment of the apparatus of the present invention shown in the drawings will be described below.

In Figures 1 to 3, a frame 1 constitutes the main body of this winding device, and is formed by pressing a thick iron plate so that the cross section is approximately U-shaped. It consists of side plates 1ay1b.

This base is provided with a hole 1c, so that it can be attached to an appropriate position, for example, on the floor of an automobile, using bolts or the like.

In the side plate 1a>Ib, holes for rotatably suspending the take-up reel 2 are provided at mutually opposing positions, and bearing bushes 1d and le made of Teflon or the like are installed in these holes, respectively.

The take-up reel 2 has a shaft 2a and a flange 2b.

2c and a shaft portion 2d, which will be described later, and the shaft 2a
It is rotatably suspended on the frame 1.

Further, the shaft 2a is configured to be attached so that one end of the belt 3 does not rotate.

The belt 3 mounted in this manner is wound on the shaft 2a between the flanges 2b and 2c at both ends of the shaft 2a.

Moreover, one-way gears (not shown) are provided facing each other on the outer circumferential surfaces of the flanges 2b and 2c, and in an emergency, the one-way gears and a locking device (not shown) engage to prevent the winding of the winding wheel 2.
The rotation of the belt 3 is stopped and the unwinding of the belt 3 is inhibited.

The belt 3 is a known type of webbing, and one end is wound around the take-up reel 2 as described above, and an anchor or buckle (not shown) is attached to the other end.

The spring case 4 is formed of resin or the like into a substantially cup shape, has an opening 4d (FIG. 2) in part, and is fixed to the side plate 1b of the frame 1 by a fixing part 4c.

Further, the hole 4a in the center is a bearing portion that rotatably suspends a latch gear 5 constituting a clutch means to be described later, and the hole 4b
(FIG. 2) shows a fixing portion of the second spring member 6, which will be described later.

In this way, this spring case 4 accommodates the second spring member 6.

Latch gear 5 has a stepped disc shape, and spring case 4
The shaft portion 5c and bearing portion 5e at both ends are rotatably suspended by the bearing portion 4a of the spring case 4 and the shaft portion 2d of the spool 2.

A one-way gear 5a is formed on the outer periphery of the latch gear 5 at the larger diameter portion (right side in Figure 1), and a spring winding portion 5b is arranged at the smaller diameter portion (left side in Figure 1). At the same time, a spring fixing slit 1-5d (Fig. 2) is provided.

The second spring member 6 serving as the second spring part is a known S-shaped or spiral-shaped member, and is stored in the spring case 4, and its outer peripheral end 6b (FIG. 2) is connected to the fixed part of the spring case 4. 4b, and its central end 6a is fixed to the slit 5d of the latch gear 5, respectively.

The first spring member 7 serving as the first spring portion is also of a known type having a spiral shape, and constitutes a spring means together with the second spring member 6, and the strength of the spring is set to be weaker than that of the second spring member 6. It is stored inside the large part of the outer peripheral edge 7.
b (Fig. 3) is connected to the spring fixing part 5e of the latch gear 5, and its center end is connected to the slit 2 of the shaft 2a as shown in Fig. 3.
e and is fixed.

In this way, the first and second spring members 7, 6, the latch gear 5
When the latch gear 5 is rotatable (turnable), that is, when both spring members 6 and 7 are connected, the resultant force of both spring members is applied to the shaft 2a as a belt winding force. act.

Next, in FIG. 2, 8 is a known electric solenoid for operating the ratchet 10, which is fixed on the board of the frame 1, and consists of a plunger 8a, a drive pin 8b, and a return spring 8CN coil 8d. .

9 is an actuator operated by solenoid 8;
A bearing portion 9a is rotatably suspended on the rotating shaft portion 1f of the frame 1.

One end of the actuator 9 (lower end in FIG. 2) is configured with a U-shaped connecting portion 9d to be connected to the solenoid 8, and is sandwiched between the drive pin 8b of the solenoid 8 and the return spring 8c. Slidingly connected.

Further, a rotation shaft 9b of a ratchet 10, which will be described later, and a stopper 90 are formed at the other end, and the ratchet 10 is suspended so as to be rotatable within a set range.

Reference numeral 10 denotes a ratchet that is rotatably suspended on the rotation shaft 9b of the actuator 9, and a tooth tip 10 that selectively meshes with the rotation bearing 10a1 and the one-way gear 5a of the latch gear 5.
b (Fig. 3).

A biasing spring 11 is provided to constantly bias the ratchet 10 to rotate clockwise with respect to the actuator 9. Therefore, the ratchet 10 is biased toward the actuator 9.
It is stopped in a state where it is in contact with the stopper 9c (Fig. 2).

In this way, the solenoid 8 and the actuator 9 constitute a control mechanism for the latch gear 5 serving as a clutch means, and when the solenoid 8 is energized and excited, the plunger 8a
The actuator 9 is moved to the left in the drawing, thereby causing the actuator 9 to rotate clockwise, and the ratchet 10 engages with the one-way gear 5a as shown in FIG. 3 to prevent the latch gear 5 from rotating in the counterclockwise direction.

When the solenoid 8 is in a non-energized state, the tooth tips 10b of the ratchet 10 are separated from the one-way gear 5a, as shown in FIG. 5, and the latch gear 5 is free to rotate.

This operation is based on the biasing force of the return spring 8c, which causes the actuator 9 to rotate counterclockwise and the tooth tip 10b of the ratchet 10 to move away from the one-way gear 5a.

Next, the control circuit of the solenoid 8 will be explained based on FIG. 6. 8d is the coil of the solenoid 8, and 12 is a switch means, which is a buckle switch installed on a buckle (not shown). ONt when the metal fitting is inserted into the buckle and locked, OF when the metal fitting such as the tongue is unlocked or released from the buckle
It has a structure that allows F.

13 is a known ignition switch for an automobile, and 14 is an automobile power source such as a battery.

Therefore, the solenoid coil 8d is connected to the buckle switch 1.
2. Battery 14 via ignition switch 13
Since the buckle switch 12 and the ignition switch 13 are both turned on, they are energized and excited.

Next, the operation of this embodiment will be explained. First, when the belt 3 is wound onto the take-up reel 2 and stored in this take-up device, the metal fittings such as the tongue are separated from the buckle. , the buckle switch 12 is turned OFF,
Therefore, since the solenoid 8 is in a de-energized state, the ratchet 10 is in the state shown in FIG. 5 (connected state), the latch gear 5 is rotatable, and the tension of the first spring member 6 is applied to the take-up reel 2. has been done.

In this state, the first spring member 7 is almost fully compressed by the second spring member 6.

Next, when the occupant pulls out the belt 3 from this state to put on the seat belt, the belt 3 is pulled out while tightening the second spring member 6.

When the buckle is further pulled out and the occupant inserts a metal fitting such as a tongue into the buckle and locks the buckle, the buckle switch 12 is turned on.

At this time, the ignition switch 13 is already ONt,
If so, the coil 8d of the solenoid 8 is energized and excited, and the ratchet 10 becomes engaged with the one-way gear 5a of the latch gear 5 (disconnected state) as shown in FIG.

Since the suction force of the solenoid 8 is set to be sufficient to inhibit the rotation of the latch gear 5, in this state, the counterclockwise rotation of the latch gear 5 is completely inhibited.

On the other hand, regarding clockwise rotation of the latch gear 5, since the ratchet 10 can rotate on the actuator 9 even when the solenoid 8 is in the suction state, the ratchet 10 is rotated against the biasing spring 11 as shown in FIG. This is possible because it rotates counterclockwise.

That is, even after a metal fitting such as a tongue is inserted into the buckle and locked, if the belt 3 is pulled out due to the behavior of the occupant, the latch gear 5 can also freely rotate counterclockwise.

In this way, when the seat belt is attached to the passenger,
Since the latch gear 5 is free to rotate clockwise (the direction in which the belt 3 is pulled out) and is prevented from rotating only in the counterclockwise direction (the direction in which the belt 3 is wound up), the tension of the second spring member 6 is
Since the tension of the first spring member 7 is no longer applied to the belt and the tension of the first spring member 7 is reduced, the belt tension when the belt is attached is reduced.

Next, when the belt is retracted, when a metal fitting such as a tongue is unlocked from the buckle by the occupant, the buckle switch 12 is turned off at this point, and the current to the coil 8d of the solenoid 8 is cut off.

Therefore, the control mechanism including the actuator 9 and the like is returned to the state shown in FIG. 5 by the counterclockwise rotational force of the return spring 8c and the latch gear 5.

As a result, the latch gear 5 is free to rotate counterclockwise, so the second spring member 6, which had been retightened, is released all at once, and while the first spring member 7 is retightened, both spring members 6
, 7 will stop at the position where the tension is balanced.

In this state, when the belt tension is high, the first spring member 7 is almost fully compressed, and the belt 3 is wound onto the take-up reel 2 by the strong tension of the second spring member 6.

Therefore, storage defects are less likely to occur.

Next, we will explain the case where the latch gear 5 is located at a position slightly different from that in FIG. 3 and the control mechanism is operated.
There may be cases where the tooth tip 10b of the ratchet 10 hits the tooth tip of the one-way gear 5a of the latch gear 5 and the solenoid 8 is unable to suction the solenoid 8, but in this case, the tension of the belt 3 is not reduced, so the latch gear 5 The ratchet 10 rotates as the latch gear 3 is pulled out, and when the latch gear 5 is no longer obstructed, the ratchet 10 completely reaches the inhibiting position and the solenoid 8
Since it also becomes a complete suction state, it can immediately become the state shown in Fig. 3.

The suction force of the solenoid 8 reaches several times the initial suction force in the complete suction state, so when the ratchet 10 is engaged with the latch gear 5, it is greater than the rotational force of the latch gear 5 and can be sufficiently suppressed.

Further, since the solenoid is designed to be able to lock the latch gear in a fully suction state, the initial suction force of the solenoid can be reduced, and there is an advantage that the solenoid can be made smaller and cost can be reduced.

In the embodiment of the present invention, the first spring part and the second spring part are constructed of separate springs as spring means and are placed side by side on the side of the winding device, but a latch gear serving as a boundary part is provided inside one mainspring spring. The boundary between the two mainspring springs can be wound concentrically, that is, in the same layer. Of course, a latch gear may be connected to the connecting portion.

Further, although the clutch means is constructed by a combination of a latch gear and a ratchet, it is of course possible to use various other locking means and braking means.

As described above, in the present invention, since the clutch means for controlling the seatbelt tension is controlled by an actuator operated by electrical input, the spring force acting on the seatbelt is selectively switched in accordance with an electrical signal. It is possible to obtain a seatbelt retractor that is adaptable to various control patterns, and it is possible to reduce the tension of the seatbelt when the seatbelt is worn based on electrical signals, thereby providing a comfortable wearing feeling. The device has the advantage of being able to immediately increase the seat belt tension in response to an electrical signal when the seat belt tension is required.

In other words, when the seatbelt is retracted, the biasing forces of both the first spring part and the second spring part act on the take-up reel, so the seatbelt can be quickly retracted, and when the occupant is wearing the seatbelt, the first spring Since only the biasing force of the seat belt acts on the seat belt, it has an excellent effect in that the occupant can wear the seat belt comfortably without feeling uncomfortable due to pressure from the seat belt.

[Brief explanation of drawings]

1 to 5 schematically show the operating state of an embodiment of the seatbelt retractor according to the present invention.
The figure is a partial cross-sectional view as seen from the front, Figures 2 to 5 are partial cross-sectional views as seen from the left side, and Figure 6 is an electric circuit diagram for explaining the operation of the solenoid that constitutes the control mechanism. . 1... Frame, 2... Take-up reel, 3... Seat belt, 5, 10...
Clutch means, 6°7... Spring means, 9...
...actuator, 12... switch means.

Claims (1)

[Claims] 1 a frame, a take-up reel that is rotatably supported by the frame and winds up the seat belt, and a first spring part whose free end is locked to the take-up reel and applies a force in the seat belt winding direction. , a second spring portion having a biasing force in the same direction as the biasing force of the first spring portion and larger than the biasing force of the first spring portion; and a second spring portion having a biasing force of the second spring portion toward the take-up reel. a clutch means for connecting and disconnecting transmission; a switch means for detecting whether the seat belt is fastened to an occupant when the vehicle is running; and a switch means for disconnecting the clutch means when the seat belt is fastened in response to a detection signal from the switch means; A seatbelt retractor comprising: an electric actuator that connects the clutch means when the seatbelt is not worn.