JP2000071936A - Seat belt retractor and seat belt device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the whole of a seat belt device more compact, and reduce weight and cost, in the seat belt device improved so as not to give an unnecessary sense of oppression to an occupant. SOLUTION: A winding force reduction mechanism 11 has a disc type bush 13 fixed to the right end of a reel shaft 7, and an annular brake drum 17 having a plurality of teeth like a ratchet on the external surface. Two grooves are formed on the bush 13, and a brake member is fitted to each of the grooves via a spring. The brake member is radially energized with the spring and kept in contact with the internal surface of a brake drum 17. Furthermore, a turnably journalled lever has one end connected to a solenoid cylinder 28 and the other end faced to the external surface of the brake drum 17.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seat belt device for restraining an occupant to a seat of a vehicle or the like, which is improved so as not to give an occupant an unnecessary feeling of pressure. In particular, the present invention relates to a seat belt device and the like that can reduce the size of the entire device and reduce the weight and cost.

[0002]

2. Description of the Related Art A seat belt device mounted on a vehicle such as an automobile usually includes a seat belt, a buckle device, and a seat belt retractor. The seat belt retractor includes a rotatable reel that winds the belt, a biasing member that biases the base end of the belt in a winding direction, and an emergency lock mechanism that locks the belt when the vehicle collides. ing. As a biasing member in the seat belt retractor, a spring-type return spring is generally used.

In such a seat belt device, in a state where the occupant sits down and wears the belt, and the excessive slack of the belt is caught in the seat belt retractor (wearing state), the occupant does not need to take off the belt from the belt. It is desirable to configure so as not to add a feeling of oppression. However, depending on the occupant's physique and the position of the seat, the amount of belt withdrawal in the wearing state varies greatly (for example, about 80 to 150 cm).
Therefore, it is very difficult to provide an appropriate biasing force with the entire amount of withdrawal.

Therefore, the applicant of the present application filed a file on September 2, 1986
In Japanese Utility Model Application No. 61-146473 on 6th, a seat belt device for solving the above-mentioned problem was proposed. In the seat belt device, a spring means for urging the belt in a winding direction is divided into a main spring and an additional spring in advance. When the normal belt is wound, a sufficient belt winding force is generated by the combined pressure of the two springs, and when the seat belt is normally worn, the belt is softly fitted to the occupant only by the urging force of the main spring.

[0005]

This device has sufficiently achieved its intended purpose of avoiding a feeling of pressure on the occupant. However, the use of two types of springs (main spring and additional spring) has increased the size of the entire apparatus. Also, a memory mechanism must be provided to maintain the relative coupling between the main spring and the additional spring. Further, when a displacement between the main spring and the additional spring occurs, a mechanism for reducing an impact force generated when correcting the displacement must be provided. For these reasons, there has been a problem that the device becomes larger, the structure is complicated, and the weight and cost are considerably increased.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and in a seat belt device or the like improved so as not to give an occupant an unnecessary feeling of pressure, the entire device is further reduced in size. It is an object of the present invention to provide a seat belt device or the like that can be reduced in weight and cost.

[0007]

In order to solve the above problems, a seat belt retractor according to the present invention comprises a rotatable reel for winding a seat belt, and an urging member for urging the reel in a belt winding direction. An emergency locking mechanism that locks the belt drawer in the event of a vehicle collision,
O that gives resistance to reel rotation in the belt winding direction
And a winding force reduction mechanism capable of N / OFF. The winding force reducing mechanism can reduce the winding force according to the situation. Therefore, a sufficient winding force can be exerted when unnecessary pressure is not applied to the occupant.

In the present invention, the winding force reducing mechanism is provided with a switching means for switching between ON and OFF, a bush attached between the reel and the urging member, and rotatable synchronously with the reel. A brake drum attached to the bush, a rotation preventing member that is interlockable with the switching means, and that prevents rotation of the brake drum when the switching means is in an ON state; And a brake member that generates frictional resistance between the interposed bush and the brake drum.

When the switching means is turned on when the reel rotates in the belt winding direction, the rotation preventing member interlocks with this to prevent the brake drum from rotating in the belt winding direction. On the other hand, the bush rotates in the belt winding direction under the urging force of the urging member. At this time, the brake member between the brake drum and the bush slips,
Friction resistance occurs between the stopped brake drum and the rotating bush. When this frictional resistance acts on the bush, resistance is added to the rotation of the reel in the belt winding direction. The switching means is preferably one that can use a solenoid or the like to convert electrical input into mechanical output.

Further, the seat belt device of the present invention
A seat belt, a buckle for fixing the end of the seat belt to the vehicle body, a rotatable reel for winding the seat belt, a biasing member for biasing the reel in a winding direction, and locking of a belt withdrawal in the event of a vehicle collision A buckle sensor for detecting that the front end of the seat belt is attached to the buckle; and a reel in the belt winding direction in the buckle-mounted state. And a winding force reducing mechanism for giving resistance to rotation.

When the buckle is attached, the winding force reducing mechanism gives resistance to the rotation of the reel, and the belt winding force is reduced. Therefore, an unnecessary feeling of pressure is not given to the occupant.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 5 are diagrams showing an embodiment of the present invention.
FIG. 1 is a front sectional view showing a seat belt retractor according to the present invention. FIG. 2 is a side sectional view showing the seat belt retractor. FIG. 3 is a front view showing a main part of a winding force reducing mechanism of the seat belt retractor. FIG. 4 is a perspective view showing a main part of the winding force reducing mechanism. FIG. 5 is a conceptual configuration diagram of a seat belt device including a seat belt retractor.

As shown in FIG. 1, the seat belt retractor 1 has a reel 2 around which a belt is wound. The reel 2 is formed by integrally forming disk-shaped flanges on left and right ends of a cylindrical body. This reel 2
It is arranged in the frame 5. The frame 5 includes right and left frame sides 5 located on both sides of the reel 2.
a and 5b. The end of the belt 10 is attached to the cylinder of the reel 2 by a known means. The belt 10 is pulled out when the reel 2 rotates in the X direction in FIG. 2, and is rewound when the reel 2 rotates in the Y direction.

The reel 2 is formed with an inner hole penetrating along the axis, and a reel shaft 7 is inserted through the inner hole. The reel 2 and the reel shaft 7 are integrally coupled to rotate synchronously. The length of the reel shaft 7 in the longitudinal direction is larger than the length of the reel 2 in the axial direction. The left end of the reel shaft 7 (the left end in FIG. 1)
It is rotatably supported by the left frame side 5b. On the left of the left frame side 5b, there is a known emergency lock mechanism 6
(See Japanese Patent Application Laid-Open No. 8-40203), and the left end of the reel shaft 7 enters the emergency lock mechanism 6 and is locked at the time of collision or the like. On the other hand, the right end side (the right end side in FIG. 1) extends through the right frame side 5a and is connected to the winding force reducing mechanism 11.

The winding force reducing mechanism 11 includes a disk-shaped bush 13 fixed to the right end of the reel shaft 7. The bush 13 is fixed to the reel shaft 7 at its axis, and rotates synchronously with the reel 2. In the bush 13, an axial center portion of a surface (the right surface in FIG. 1) opposite to the side fixed to the reel shaft 7 includes:
The projection 13a is formed. A winding spring 15 for winding the belt is attached to the projection 13a. The biasing force of the winding spring 15 is transmitted to the reel 2 via the bush 13. Thus, the belt 10 attached to the reel 2 is urged in the winding direction.

An annular brake drum 17 is attached to the outer periphery of the bush 13. The inner diameter of the brake drum 17 is formed slightly larger than the diameter of the bush 13. Therefore, there is a slight gap between the bush 13 and the brake drum 17. Same brake drum 1
A plurality of pawls 17a are formed in a ratchet shape on the outer periphery of 7.

As shown in FIGS. 3 and 4, the bush 13 has two grooves 23 at positions 180 ° left and right.
A and 23B are formed. That is, the grooves 23A, 2
3B are individually formed from a position where the outer peripheral portion is opposed to a position near the central portion. Springs 24 are attached to the bottoms of the grooves 23A and 23B, respectively. Same spring 2
A brake member (top) 26 is attached to the free end of the fourth member 4. The brake member 26 is made of a material such as a nylon resin. The brake member 26 includes a spring 24
Urged radially outward by the member 2
The outer surface of 6 is in contact with the inner peripheral surface of the brake drum 17. Note that the outer surface of the brake member 26 has a sharper radius than the inner peripheral surface of the brake drum 17.

Further, a solenoid cylinder 28 is attached to the right frame side 5a at a position below the brake drum 17. Solenoid cylinder 28
Incorporates a solenoid 28a, and this solenoid 28a
The rod 28b moves forward and backward in accordance with ON / OFF of the control signal. That is, when the solenoid 28a is ON, the rod 28b is retracted to the left, and conversely, when the solenoid 28a is OFF, it protrudes. As shown in FIG. 2, an L-shaped lever 29 is connected to the solenoid cylinder. The lever 29 is rotatably supported on the right frame side 5a. One end (lower end in FIG. 2) of the lever 29 is connected to the solenoid cylinder 28, and the other end (upper end in FIG. 2) faces the outer peripheral surface of the brake drum 17.

When the solenoid 28a is turned on and the solenoid cylinder 28 is retracted, the lever 29
Rotates upward, and engages with the pawl 17a of the brake drum 17. Conversely, when the solenoid 28a is turned off and the solenoid cylinder 28 advances, the lever 29 rotates downward and the engagement of the brake drum 17 with the pawl 17a is released. Lever 29 and claw 1 of brake drum 17
At the time of engagement with 7a, rotation of the brake drum 17 is prevented.

Such a seat belt retractor 1 is
It forms part of a seat belt device as shown in FIG. The seat belt device includes a seat belt retractor 1,
A buckle 31 and a power supply 33 are provided in addition to the belt 10.

The buckle 31 is fixed to the vehicle body, and can be engaged with a tongue-shaped tongue 10a provided at the tip (free end) of the belt 10. The buckle 31
A buckle sensor (not shown) is attached. With this buckle sensor, the buckle 31 and the tongue 10
a is detected (when the belt is attached) and when it is not engaged (when the belt is not attached). The buckle sensor includes a buckle switch, and the buckle switch turns on the power supply 33 at the time of the engagement,
At the time of the non-engagement, it is set to the OFF state.

The power supply 33 is connected to the solenoid cylinder 2
8 and a buckle switch of the buckle 31 are connected via a cable or the like. And
When the power supply 33 is turned on when the buckle switch is engaged, the solenoid 28a is also turned on, and the solenoid cylinder 28 is retracted. Conversely, if the power supply 33 is turned off when the buckle switch is not engaged, the solenoid 28a
Is also turned off, and the solenoid cylinder 28 advances.

Next, the operation of the seat belt device having the above configuration will be described. First, before the passenger wears the seat belt, the belt 10 is wound around the reel 2,
A belt 10 is housed in the seat belt retractor 1. In this case, since the buckle switch is in the OFF state, the voltage from the power supply 33 is not supplied to the solenoid 28a. Therefore, since the solenoid 28a is turned off and the solenoid cylinder 28 advances, and the lever 29 rotates downward, it does not engage with the claw 17a of the brake drum 17, and the brake drum 17 is frictionally locked to the outside of the bush 13. Being rotated freely. Therefore, the urging force of the winding spring 15 is directly transmitted to the reel 2 via the bush 13.

In this state, when the occupant wears the seat belt, the belt 10 is gradually pulled out. When pulling out the belt 10, the reel 2 rotates in the X direction. At this time, since no frictional resistance acts on the bush 13, no extra force is required to pull out the belt 10. After pulling out the belt 10, the tongue 10a is buckled 31.
, The engagement is detected by the buckle sensor. At the same time, when the occupant releases the belt 10,
The reel 2 tries to rotate in the Y direction under the urging force of the winding spring 15, and the belt 10 is urged in the winding direction.

At this time, since the buckle sensor detects the engaged state, the power supply 33 is turned on. Then, the solenoid 28a is also turned on, and the solenoid cylinder 2
8 is evacuated. When the solenoid cylinder 28 retracts,
The lever 29 rotates upward and engages with the pawl 17a of the brake drum 17. This engagement prevents the rotation of the brake drum 17.

On the other hand, the bush 13 tries to rotate in the Y direction under the urging force of the winding spring 15. At this time, since the brake member 26 is urged by the spring 24 and is in contact with the inner peripheral surface of the brake drum 17, the brake drum 17 at rest and the bush 13 urged are
And frictional resistance is generated between them. The frictional resistance acting on the bush 13 adds resistance to the rotation of the reel 2 in the Y direction (belt winding direction). Therefore, belt 1
Unnecessary pressure on the occupant from zero can be reduced.

From this state, the tongue 10a and the buckle 3
When the engagement with the buckle 1 is released, this is detected by the buckle sensor, and the buckle switch is turned off. Therefore, when the solenoid 28a is OFF and the solenoid cylinder 2
As the lever 8 moves forward and the lever 29 rotates downward, the engagement of the brake drum 17 with the pawl 17a is released. In this case, the brake drum 17 can rotate freely. Then, when the occupant releases the hand from the belt 10, the reel 2 rotates in the Y direction under the urging force of the winding spring 15,
The belt 10 is wound up with a sufficient retraction force.

Even if the solenoid 28a is ON and the solenoid cylinder 28 is retracted, and the lever 29 and the claw 17a of the brake drum 17 are engaged, the belt 1
Withdrawal of 0 is performed smoothly. That is, when the belt 10 is pulled out, the reel 2 rotates in the X direction, so that the claw 17a comes in contact with the lever 29 and sequentially climbs over it. Therefore, the rotation of the brake drum 17 in the X direction is not prevented.

The seatbelt device according to the present invention can reduce unnecessary pressure on the occupant through the belt 10. In addition, since the entire device is small and has a simple structure, the weight and cost can be reduced.

[0030]

As is apparent from the above description, according to the present invention, it is possible to avoid giving an occupant an unnecessary feeling of pressure when wearing the belt. Further, there is an effect that the entire device can be reduced in size and the weight and cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a front sectional view showing a seatbelt retractor described in the present embodiment.

FIG. 2 is a side sectional view showing the seat belt retractor.

FIG. 3 is a front view showing a main part of a winding force reducing mechanism of the seat belt retractor described in the present embodiment.

FIG. 4 is a perspective view showing a main part of the winding force reducing mechanism.

FIG. 5 is a conceptual configuration diagram of a seat belt device including the seat belt retractor described in the present embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Seat belt retractor 2 Reel 10 Belt 11 Winding force reduction mechanism 13 Bush 15 Winding spring 17 Brake drum 26 Brake member 28 Solenoid cylinder 28a Solenoid 29 Lever 31 Buckle

Claims (3)

[Claims] 1. A rotatable reel for winding a seat belt, an urging member for urging the reel in a belt winding direction, an emergency lock mechanism for locking a belt withdrawn in the event of a vehicle collision, and a belt winding. O that gives resistance to reel rotation in the take-off direction
A seat belt retractor comprising: a winding force reduction mechanism capable of N / OFF. And a bush that is mounted between the reel and an urging member, and is rotatable in synchronization with the reel. A brake drum that is interlocked with the switching means, a rotation preventing member that prevents rotation of the brake drum when the switching means is in an ON state, and is interposed between the bush and the brake drum. The seat belt retractor according to claim 1, further comprising: a brake member that generates frictional resistance between the bush and the brake drum. 3. A seat belt, a buckle for fixing a front end of the seat belt to a vehicle body, a rotatable reel for winding the seat belt, an urging member for urging the reel in a winding direction, and at the time of collision of the vehicle. A retractor having an emergency lock mechanism for locking a belt withdrawal, comprising: a buckle sensor for detecting that the front end of the seat belt is attached to the buckle; And a winding force reducing mechanism for giving resistance to rotation of the reel in the direction.