JPH10152020A - Seat belt take-up device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a seat belt take-up device having a favorable take-up characteristic while having a sufficient take-up force and a webbing take-up amount. SOLUTION: In a pre-tensioner for removing slack of a seat belt, wherein a piston 8 movably guided within a cylinder 9 is driven in an emergency with an explosion pressure of a gas generating agent 15 contained in a gas generator 11, a driving force is applied to a wire 6 coupled to the piston 8, and a webbing is tightened with the driving force of the wire 6, said gas generating agent 15 is one formed in cylindrical block within which are formed a plurality of communication holes 19 leading from an ignition heater 17 side to the piston 8 side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seat belt tightening device (pretensioner) for removing slack of a webbing at the time of a vehicle collision, and more particularly, to driving a piston movably guided in a cylinder by gas pressure to a webbing. The present invention relates to an improvement in a seat belt tightening device having a driving means for exerting tension.

[0002]

2. Description of the Related Art Conventionally, a seatbelt device for holding a vehicle occupant or the like safely in a seat tends to reduce a retracting force of a webbing by a retractor in order to reduce a feeling of wearing the webbing by the occupant. Inevitably, the play of the seat belt increases, and the restraint is delayed due to the play of the seat belt, so that the occupant cannot be effectively and safely restrained.

[0003] In order to eliminate the play of the seat belt by pulling the webbing in tension in an emergency,
Some seat belt devices incorporate a seat belt tightening device that instantaneously rotates a winding shaft of a retractor in a winding direction and a device that instantaneously retracts a buckle in a webbing tension direction. For example, the retractor 81 with a pretensioner shown in FIG. 8 includes a winding shaft on which the webbing 82 is wound or pulled out freely.
A pretensioner 84, which is a seat belt tightening device for rotating a winding shaft in a direction in which the seat belt is not slackened, is provided on one base side wall 83a of the retractor base 83 formed in a substantially U shape. I have. The pretensioner 84 exerts tension on a wire 85, which is a transmission member wound around a pulley (not shown) attached to one end of the take-up shaft, and the wire 85 pulls the take-up shaft in the webbing take-up direction and drives it. In this way, the webbing 82 in a state of being laid over the occupant is drawn in an emergency, and has a driving unit 86 for applying a tension to the wire 85.

The driving means 86 comprises a piston 87 connected to one end of a wire 85, a cylinder 88 for slidably receiving the piston 87, and a cylinder 88
And a gas generator 89 connected to the gas generator 89. The gas generator 89 has a built-in ignition heater and a gas generating agent, and energizes the ignition heater according to a signal from a collision sensor, and ignites the gas generating agent by the heat generated by the ignition heater to generate gas.

[0005] The piston 87 in the cylinder 88 is actuated by the expansion pressure of the gas generated from the gas generator 89.
Is driven upward, the take-up shaft is driven in the webbing take-up direction via the wire 85, so that the webbing 82 which is in a state of being wrapped around the occupant is drawn in, and the play of the seat belt is eliminated. . By the way, in the seat belt device as described above, in order to enhance the safety of the occupant in the event of a vehicle collision, it is necessary to increase the webbing tightening force and the webbing tightening amount by the pretensioner 84 so that the occupant is more strongly restrained by the seat. is there. However, since the pretensioner 84 using the gas generator 89 as the driving means utilizes the explosive force of the gas generating agent as its driving force, it is necessary to increase the webbing tightening force or the amount of webbing tightening by increasing the gas generation force. Although the amount of the gas generating agent must be increased, increasing the amount of the gas generating agent of the gas generator 89 has limitations in handling and safety. In addition, when the explosive power of the gas generating agent is increased, the possibility of damaging mechanical parts such as cylinders and pistons also increases.

Further, in order to tighten the webbing 82 more, it is generally necessary to increase the gas pressure in the cylinder 88 in the latter half of the tightening time when the tension of the webbing 82 becomes high to increase the webbing tightening force. However, in the driving means using the explosive force of the gas generating agent as described above, the gas pressure increases immediately after the explosion of the gas generating agent, and then gradually decreases, so that the webbing tightening force and the driving time are controlled. Therefore, it was difficult to obtain appropriate webbing tightening characteristics, and it was difficult to obtain good restraint performance.

Therefore, as in the seat belt tightening device disclosed in Japanese Utility Model Laid-Open No. 6-1040 and Japanese Utility Model Laid-Open No. 6-6131, a plurality of gas generators and pretensioners are provided, and one gas generator is provided. When the gas pressure drops due to the explosion, the next gas generator is exploded to control the continuation of the webbing tightening force and its driving time to improve the webbing tightening characteristics and obtain good restraint performance. Means have been proposed.

[0008]

However, in the case where a plurality of gas generators are continuously exploded, a plurality of ignition devices for the gas generators are required, which increases costs and space. Also, a control mechanism for controlling the ignition timing is required. Therefore, an object of the present invention is to solve the above-mentioned problems, and to provide a seatbelt tightening device that is less expensive and space-saving than having a plurality of gas generators.

[0009]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a piston which is guided movably in a cylinder by an explosion pressure of a gas generating agent incorporated in a gas generator in an emergency. A seatbelt tightening device for applying a driving force to a connected transmission member, and tensioning the webbing by the driving force of the transmission member to remove play of the seatbelt, wherein the gas generating agent has a block shape. This is achieved by a seat belt tightening device.

[0010] Preferably, a communication hole from the ignition heater to the piston is formed in the block-shaped gas generating agent. Alternatively, the block-like gas generating agent may be formed in a hollow cylindrical shape, and the hollow portion may be filled with a granular gas generating agent. Further, the object of the present invention is to drive a piston movably guided in a cylinder by an explosion pressure of a gas generating agent incorporated in a gas generator in an emergency to drive a transmission member connected to the piston. A seatbelt tightening device for exerting a force and tensioning the webbing by a driving force of the transmission member to eliminate play of the seatbelt, wherein a gas generating agent is also disposed in a space between the piston and the gas generator. This is achieved by a seat belt tightening device characterized by being provided.

Preferably, the gas generating agent provided in the space between the piston and the gas generator has a block shape. According to the above configuration, the combustion of the gas generating agent is not performed at once, but can be continued for a long time. Therefore, the expansion pressure of the gas can be maintained for a long time while maintaining the predetermined pressure. That is, a stable webbing tightening force is maintained, and the webbing tightening characteristics can be improved while having a sufficient webbing tightening amount.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the accompanying drawings. As shown in FIG. 1, a retractor 1 with a pretensioner according to a first embodiment includes:
The webbing 2 is provided with a take-up reel 3 on which the webbing 2 can be wound or pulled out. The retractor base 4 formed in a substantially U-shape is fitted into the take-up reel 3 on one base side wall 4a. Webbing 2 with winding shaft (not shown)
A pretensioner 5 for rotating in a direction in which the slack is removed is provided.

The pretensioner 5 applies a tension to a wire 6 which is a transmission member wound around a pulley (not shown) which is attached to one end of a winding shaft, and the wire 6 winds the winding reel 3 around the webbing 2. The webbing 2, which is in a state of being stretched over an occupant, is pulled in an emergency by being driven to be pulled in the take-off direction, and is provided with a driving means 7 for applying tension to the wire 6.

As shown in FIG. 2, the driving means 7 comprises a piston 8 connected to one end of the wire 6 and a piston 8
And a substantially cylindrical housing 1 connected to the base end of the cylinder 9 so as to extend substantially perpendicularly to the axial direction of the cylinder 9.
0, and a gas generator 11 disposed on the opening side of the housing 10 opposite to the portion connected to the cylinder 9.

The housing 10 includes the gas generator 1.
The base end of the cylinder 9 is fixed to an opening 12 drilled at the opposite end where the 1 is disposed, and a hole 13 drilled opposite the opening 12 is connected to the piston 8. The wire 6 penetrates. The gas generator 11 housed in the housing 10 has a gas generating agent 1 inside a case 14.
5, and an ignition charge 18 is stored together with an ignition heater 17 at one end (right end in FIG. 2).

The gas generating agent 15 is made of a cylindrical block-shaped gas generating agent, and has a plurality of communicating holes 19 formed therein from the side of the ignition heater 17 to the side of the piston 8. The ignition heater 17 has a configuration in which a heating element is positioned at the center of the ignition charge 18. When the heating element reaches a predetermined temperature, the ignition charge 18 is ignited to burn the gas generating agent 15.

A signal line 20 connected to a control circuit (not shown) is connected to the gas generator 11 so that a detection signal from a vehicle acceleration detecting means such as an acceleration sensor for detecting a collision of the vehicle can be provided. Based on this, the ignition heater 17 in the case 14 can be ignited, and the ignition timing of the gas generator 11 is appropriately controlled. Next, the operation of the retractor 1 with a pretensioner will be described.

In a normal running state of the vehicle, the take-up reel 3 is rotatable because the pretensioner 5 is not engaged with the take-up shaft. Therefore, the webbing 2 can be wound by the urging force of the winding spring, and the webbing 2 can be pulled out against the spring force. When a certain amount of deceleration such as sudden braking occurs in the vehicle, the emergency locking mechanism of the retractor operates to lock the rotation of the take-up reel 3 in the webbing pull-out direction.
Thereby, the extension of the webbing 2 is prevented,
Since the collision sensor does not output a detection signal, the driving means 7 of the pretensioner 5 does not operate.

When an extremely large predetermined deceleration occurs, such as at the time of a vehicle collision, the collision sensor detects the deceleration and outputs a detection signal. Then, FIG.
As shown in (2), the heating element of the ignition heater 17 reaches the ignition temperature and ignites the igniter 18, so that the flame reaches the inside of the communication hole 19 and burns the gas generating agent 15. As shown in FIG. 4, the gas generated by the combustion of the gas generating agent 15 crushes the closing plate portion of the case 14 and jets it into the housing 10, and the expansion pressure of the gas acts on the piston 8. Then, the piston 8 is rapidly moved upward (in the direction of the arrow X). By the driving force of the piston 8,
When the wire 6 is rapidly pulled in the direction of the arrow X with a predetermined magnitude of force, the take-up reel 3 is driven in the direction in which the webbing 2 is taken up, so that the webbing 2 that has been stretched over the occupant is retracted. The play of the seat belt is eliminated.

At this time, since the gas generating agent 15 is in the form of a block having a small surface area and burns gradually from the inside of the communication hole 19, the burning of the gas generating agent 15 is not performed at once,
Can last longer. Therefore, the gas generated by the combustion of the gas generating agent 15 can maintain the state where the predetermined expansion pressure is maintained for a long time. That is, the driving unit 7 including the gas generator 11 can maintain a stable webbing tightening force, and can improve the webbing tightening characteristics while having a sufficient webbing tightening amount. Therefore, the retractor 1 with a pretensioner according to the first embodiment can obtain good restraint performance.

FIG. 5 is a sectional view of a main part of a gas generator 21 according to a second embodiment of the present invention. This gas generator 21
In the first embodiment, a case 23 is filled with a gas generating agent 22 and one end (right end in FIG. 5) houses an ignition charge 18 together with an ignition heater 17. Similar to the generator 11. However, gas generating agent 2
2 is a block-like portion 25 made of a gas generating agent formed in a hollow cylindrical block shape, and a granular portion 26 made of a granular gas generating agent packed in a hollow hole 24 of the block-like portion 25. Have.

Therefore, based on a detection signal from a vehicle acceleration detecting means for detecting a vehicle collision or the like, the ignition heater 1
When the ignition of the ignition charge 18 occurs, the flame of the ignition charge 18 instantaneously burns the granular portion 26 of the gas generating agent 22 and further burns the block-like portion 25. Then, the gas generated by the combustion of the granular portion 26 and the block-shaped portion 25 crushes the closing plate portion of the case 14 and jets out into the housing 10.

That is, the gas generator 21 of the second embodiment
Since the ignitability of the gas generating agent 22 is improved by filling the gas generating agent into the hollow hole 24, the first
The rise of gas pressure immediately after ignition is faster than that of the gas generator 11 of the embodiment, and a predetermined high expansion pressure can be obtained instantaneously. Therefore, the expansion gas can be instantaneously generated with the ignition of the ignition heater 17, and the driving means including the gas generator 21 can instantly tighten the seat belt.

Further, the gas generator 21 includes a granular part 26.
Since the block-shaped portion 25 gradually burns after burning, the burning of the gas generating agent 22 is not performed at once, and the burning can be continued for a long time. Therefore, the gas generated by the combustion of the gas generating agent 22 can maintain the state where the predetermined expansion pressure is maintained for a long time, similarly to the gas generator 11.

Next, a pretensioner driving means 34 according to a third embodiment of the present invention will be described with reference to FIG.
Note that the same reference numerals are given to the same components as those in the above-described embodiment, and detailed description thereof will be omitted. The driving means 34
As shown in FIG. 6, a piston 8 connected to one end of the wire 6, a cylinder 9 slidably receiving the piston 8, and a base end of the cylinder 9 having an angle with respect to the axial direction of the cylinder 9. A substantially L-shaped housing 10 is connected and extended so as to extend with a gas generator, and a gas generator 31 is disposed on an opening side of the housing 10 opposite to a portion connected to the cylinder 9. What is done
This is almost the same as the first embodiment. The configuration of the gas generator 31 may be selected from the gas generators 11 and 21 of the first or second embodiment, and may be disposed.
A conventional gas generator packed with a granular gas generating agent may be used.

In the driving means 34 of the third embodiment, a gas generating agent 32 is disposed in a space in the housing between the piston 8 and the gas generator 31. The gas generating agent 32 absorbs moisture so that the ignitability does not decrease.
It is covered with a moisture-proof case 33. The moisture-proof case 33 is
It is made of a material such as a thin plastic, a thin rubber, a nonwoven fabric, or a paper, and is broken by the combustion gas generated by the gas generator 31.

Therefore, based on a detection signal from a vehicle acceleration detecting means for detecting a collision of the vehicle, etc., the gas generator 31 is detected.
Generates combustion gas, and the heat of this gas breaks the moisture-proof case 33 and ignites the gas generating agent 32 inside. Therefore, after the gas generating agent of the gas generator 31 is burned, the gas generating agent 32 disposed behind the piston 8 burns, so that the combustion gas driving the piston 8 maintains the predetermined expansion pressure. It can last long. Therefore, the driving unit 34 can maintain a stable webbing tightening force, and can improve the webbing tightening characteristics while having a sufficient webbing tightening amount.

The seat belt tightening device according to the present invention comprises:
The configuration is not limited to the configuration of the pretensioner 5 in the above embodiment in which the piston 8 draws and drives the winding shaft in the webbing winding direction via the wire 6. For example, the pretensioner 41 according to the fourth embodiment shown in FIG. 7 is provided on a base side wall of the retractor.
A drive means 43 is provided for driving the winding shaft 42 of the retractor to rotate in the webbing winding direction.

The driving means 43 drives a pinion gear 44 connected to the end of the winding shaft 42, a rack 45 which is a transmission member having rack teeth 45a meshing with the pinion gear 44, and presses the rack 45. A piston 46;
A cylinder 47 which slidably receives the piston 46
And a housing 48 for communicating and connecting the base end of the cylinder 47 and the gas generator 49.

In the pretensioner 41 of the fourth embodiment, a gas generating agent 50 is disposed in a space in the housing between the piston 46 and the gas generator 49. The gas generating agent 50 has substantially the same configuration as the gas generating agent 32 of the third embodiment, and is covered by a moisture-proof case 51. Therefore, after the gas generator 49 generates the combustion gas based on the detection signal from the vehicle body acceleration detecting means such as an acceleration sensor for detecting a vehicle collision or the like, the gas generating agent 50 disposed behind the piston 46 is used. Burns.

Therefore, the combustion gas that presses and drives the piston 46 can maintain the state where the predetermined expansion pressure is maintained for a long time. Therefore, a driving means 43 for rotating the winding shaft 42 in the webbing winding direction via the rack 45 and the pinion gear 44 moved downward by the piston 46.
Can maintain a stable webbing tightening force, and can improve webbing tightening characteristics while having a sufficient webbing tightening amount.

It should be noted that the present invention is not limited to the above embodiments, but can take various forms based on the gist of the present invention. For example, in the above-described embodiment, the case where the seat belt tightening device according to the present invention is attached to the retractor has been described, but the seat belt tightening device of the present invention is not limited thereto, and the buckle itself may be momentarily moved in the webbing tension direction. It is also possible to apply the present invention to a seat belt tightening device that draws in a seat belt. Further, the ignition means of the gas generator is not limited to the ignition signal of the electric detection means as described above, and a mechanical ignition means using an inertial body may be used.

[0033]

As described above, in the seat belt tightening device of the present invention, the combustion of the gas generating agent is not performed at once, and can be continued for a long time. Therefore, the expansion pressure of the gas is increased while maintaining the predetermined pressure. Can last. That is, the driving force of the transmission member driven by the explosion pressure of the gas generating agent is maintained for a long time, and a sufficient stroke can be obtained.

Accordingly, it is possible to provide a seat belt tightening device which has a sufficient webbing tightening force and a sufficient webbing tightening amount while having a small space, and has good webbing tightening characteristics.

[Brief description of the drawings]

FIG. 1 is a fragmentary front view of a main part of a retractor with a pretensioner according to a first embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a main part of the driving means shown in FIG.

FIG. 3 is a sectional view of a main part showing an operating state of a driving unit shown in FIG. 2;

FIG. 4 is a sectional view of a main part showing an operation state of a driving unit shown in FIG. 2;

FIG. 5 is a longitudinal sectional view of a gas generator according to a second embodiment of the present invention.

FIG. 6 is a sectional view of a main part of a driving unit according to a third embodiment of the present invention.

FIG. 7 is a cutaway side view of a main part of a pretensioner according to a fourth embodiment of the present invention.

FIG. 8 is a fragmentary front view of a conventional retractor with a pretensioner.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Retractor with pretensioner 2 Webbing 5 Pretensioner 6 Wire 7 Drive means 8 Piston 9 Cylinder 11 Gas generator 15 Gas generating agent 17 Ignition heater

Claims (2)

[Claims] 1. A driving force is applied to a transmission member connected to a piston by driving a piston movably guided in a cylinder by an explosion pressure of a gas generating agent incorporated in a gas generator in an emergency, A seat belt tightening device for removing play of a seat belt by tensioning webbing by a driving force of the transmission member, wherein the gas generating agent has a block shape. 2. A driving force is exerted on a transmission member connected to the piston by driving a piston movably guided in a cylinder by an explosion pressure of a gas generating agent incorporated in the gas generator in an emergency, A seat belt tightening device for removing play of a seat belt by tensioning a webbing by a driving force of the transmission member, wherein a gas generating agent is also disposed in a space between the piston and the gas generator. A seat belt tightening device characterized by the above-mentioned.