JPH0880809A - Pretensioner of seat belt device - Google Patents

Abstract

PURPOSE: To wind sufficient amount of webbing in emergency by eliminating idle running of a rotor. CONSTITUTION: The pretensioner of a seat belt device is provided with a take-up shaft whose rotation is energized in the direction to take-up webbing, a casing 30 having a cylindrical inner wall face 31 which is concentric with the take-up shaft, an engaging means 20, which is arranged in the casing 30, connected to the take-up shaft and rotated together with the take-up shaft in a body, a rotor 40, which is arranged between the casing 30 and the engaging means 20 and supported on the casing 30 so as to be rotated concentrically with the take-up shaft and a pawl 50, which is rotatably supported on the rotor 40. An inlet port 35 for the gas discharged from a gas generator 34 is formed in the casing, and a control wall 36 for controlling gas flow direction, which nearly abuts on the outer wall of the rotor, is formed in the vicinity of the gas inlet port 35 in the cylindrical inner wall face of the casing. In addition, a pawl section 52, which is projected on the rotor so as to be capable of engaging with the engaging means 20, and a leg section 53, which is projected out of the rotor to abut on the cylindrical inner wall face of the casing, are formed in the pawl 50. A pawl leg section is formed into an arc which has its center in the rotation center C of the pawl 50.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seat belt worn by an occupant in a vehicle collision, by tightening the webbing of the seat belt to remove the slack of the occupant, thereby minimizing the distance in which the occupant moves forward to minimize windshield and steering. The present invention relates to a pretensioner for a seat belt device that prevents an injury caused by hitting a vehicle or the like.

[0002]

2. Description of the Related Art A seat belt device for a vehicle is designed to restrain an occupant with a webbing when a vehicle collides, and this webbing retractor is designed to prevent the occupant from feeling the pressure of the webbing. The winding force is relatively weak. As a result, when the seat belt is in use, there is a slight gap between the webbing and the occupant. Therefore, even if the pulling-out of the webbing from the winding device is stopped at the time of a vehicle collision, it is expected that the occupant will move in the collision direction by this gap before the occupant is reliably restrained by the webbing.

In order to prevent such a danger, there is provided a pretensioner for a seat belt device that tightens the webbing to remove the slack in the event of a vehicle collision. Conventionally, this type of pretensioner operates a gas generator in an emergency, and this gas pressure causes the take-up shaft of the seat belt retractor to rotate in the take-up direction, so that the slack of the webbing is removed from the take-up shaft of the retractor. There is something to wind up and remove. As such a pretensioner, for example, Japanese Patent Publication No. 59-1565.
7, JP-A-5-69793, and JP-A-6-24.
The one described in Japanese Patent No. 294 is known.

The one disclosed in Japanese Patent Publication No. 59-15657 is provided with a rapid rotation device connected to a webbing retractor by a driving gas, and this rapid rotation device has two ring-shaped chambers, a front and a rear chamber. When the driving gas reaches both ring-shaped chambers through the holes of the shaft of the rapid rotation device, the shaft inserted into the rear ring-shaped chamber has a webbing take-up. The blade is inserted into the hole of the side inner plate of the apparatus, and is rotated in the ring-shaped chamber until one blade abuts the other blade, and the winding shaft is rotated in the winding direction.

Further, the one disclosed in Japanese Patent Application Laid-Open No. 5-69793 has a cylinder divided into an operating space and an engaging space by a piston, and is engaged on a take-up shaft side attached to a seat belt take-up shaft. When the means (ratchet) is disengageably arranged with the piston side engagement means (barret) in the engagement space and the gas generated by the gas generator is introduced into the working space, the piston side engagement means moves toward the inner diameter side. The valet is displaced and engages with the winding shaft side engaging means, and the gas pressure also acts on the blade portion of the piston to rotate the piston around the axis, and this rotational force is wound through both engaging means. It is transmitted to the take-up shaft and rotates the take-up shaft in the take-up direction.

Further, the one disclosed in Japanese Patent Laid-Open No. 6-24294 includes a drive rotating member connected to a power source,
A driven rotating member (drum) connected to the webbing take-up shaft.
And an engaging member (roller pin) interposed between the two members
And a driven rotating member (clutch plate) provided with rotation resistance between the driving rotating member and the driven rotating member, and the driven rotating member is engaged with the driven rotating member in cooperation with the driven rotating member. A concave portion for supporting the member is formed, and the engagement member engages between the driving rotation member and the driven rotation member due to the shift of the rotational phase of the driven rotation member and the driven rotation member, resulting in a clutch engagement state. It is configured to rotate the winding shaft in the winding direction.

As described above, in the conventional type of pretensioner, the engaging means, which rotates by gas pressure only in an emergency, is connected to the take-up shaft, and otherwise the take-up shaft can rotate freely. It has a structure that does not hinder the operation of the seat belt in the normal state.

[0008]

However, all of the conventional examples disclosed in Japanese Examined Patent Publication No. 59-15657 and Japanese Patent Laid-Open No. 5-69793 are pins (shafts inserted in the rear ring-shaped chamber, pistons). Although the operation of the bullet of the side engaging means and the rotation of the rotor (the outer cylinder of the rapid rotation device, the piston) occur at the same time, they do not always operate at the same time. If the rotor starts to rotate first, the blades or bullets may spin, and the engaging means may not immediately connect to the take-up shaft, and a sufficient amount of webbing may not be taken up. Especially, since the area of the vane or the bullet receiving the gas pressure is larger than the pressure receiving area of the pin, there is a high possibility that the vane or the bullet will spin faster than the pin operates.
Further, in the one disclosed in Japanese Patent Application Laid-Open No. 6-24294, since the clutch plate is actuated by the rotation of the rotor (driving rotary member), the rotor is rotated until the clutch plate and the driven rotary member are connected via the roller pin. Will spin idle.

The present invention has been made in view of the above problems of the prior art. The object of the present invention is to eliminate idling of the rotor and take up a sufficient amount of webbing in an emergency. It is intended to provide a pretensioner for a seat belt device that can be used.

[0010]

To achieve the above object, the pretensioner of the seat belt device according to the present invention is concentric with the take-up shaft that is rotationally biased in the webbing take-up direction. A casing having a cylindrical inner wall surface, an engaging means disposed in the casing and connected to the winding shaft to rotate integrally with the winding shaft, and a winding device disposed between the casing and the engaging means. A rotor, which is concentric with the shaft and is rotatably supported by the casing, and a pawl, which is rotatably supported by the rotor, has an inlet for gas discharged from the gas generator, and a casing near the gas inlet. Forming a restriction wall on the inner wall surface of the cylinder that substantially abuts the outer wall surface of the rotor and restricts the gas flow direction, and a pawl portion that protrudes into the rotor in the pawl and is engageable with the engaging means, and protrudes outside the rotor. Casing circle It is formed with an inner wall surface abutting the legs. Further, the pawl leg portion is formed in an arc shape centered on the center of rotation of the pawl.

[0011]

When the gas generator is activated in an emergency, the gas is supplied from the gas inlet to the space surrounded by the regulating wall in the casing, the outer wall surface of the rotor, and the pawl legs protruding outside the rotor. Since the pawl is rotatably supported by the rotor, the pawl rotates due to the gas pressure applied to the leg portion, and the pawl claw portion engages with the engaging means. The engaging means is connected to the take-up shaft that is urged to rotate in the webbing take-up direction and rotates integrally with the take-up shaft, so that the gas pressure causes the webbing to take-up on the take-up shaft. Will be done. Further, by forming the pawl leg in an arc shape centering on the center of rotation of the pawl, the pawl leg is always in contact with the inner wall surface of the cylinder of the casing when the pawl is rotated, so that gas tightness can be maintained. .

[0012]

EXAMPLES Examples will be described with reference to the drawings. 1 is a side sectional view of a main part of the apparatus, FIG. 2 is a front view of the inside of the apparatus, FIG. 3 is a front view showing an engaged state of a clutch mechanism inside the apparatus, and FIG. It is a front view of the inside of this device.

Reference numeral 11 is a winding shaft for winding the webbing 12 of the seat belt. The winding shaft 11 has a housing 10
It is rotatably supported by. A square shaft portion 13 is formed at one end of the winding shaft 11. The tip end portion of the square shaft portion 13 is fitted into a spiral spring unit 14 that urges the winding shaft 11 to rotate in the winding direction of the webbing 12.

Reference numeral 20 is a ratchet which is an engaging means arranged in the casing 30. The engaging means 20 is connected to the winding shaft 11 by fitting the base end portion of the angular shaft portion 13 of the winding shaft 11 into a square hole 21 provided at the center thereof, and is integrated with the winding shaft 11. To rotate. Engaging teeth 22 are formed on the outer periphery of the engaging means 20. This engaging tooth 22
Has a tooth profile inclined rearward with respect to the winding direction of the webbing 12.

The casing 30 has a cylindrical shape and has a cylindrical inner wall surface 31 which is concentric with the winding shaft 11 (and therefore concentric with the engaging means 20). Reference numeral 32 is a cover that covers the open end of the casing 30 on the main spring unit 14 side.

The casing 30 is connected to a gas generator 34 on the outer side of the casing 30 via a communication pipe 33. Then, the gas discharged from the gas generator 34 is supplied to the casing 3 at a portion of the casing 30 that is connected to the communication pipe 33.
A gas inflow port 35 is formed to allow the gas to flow into the interior of the chamber. Further, on the cylindrical inner wall surface 31 of the casing 30 near the gas inflow port 35, a regulation wall 36 for regulating the flowing direction of the inflowing gas is formed. The restriction wall 36 is formed such that its tip portion substantially contacts the outer wall surface of the rotor 40.

A rotor 40 is arranged between the engaging means 20 and the casing 30. The rotor 40 has a cylindrical shape with one end side (cover 32 side) open,
The center of rotation is concentric with the take-up shaft 11 (hence concentric with the engaging means 20), and is rotatably supported by the casing 30.

The rotor 40 is provided with a recess 41, and the pawl 50 is rotatably supported by the recess 41. The pawl 50 includes a center portion 51, a claw portion 52, and a leg portion 5.
3 and 3. Then, the communication pipe 33, the casing 30,
The rotor 40, the restriction wall 36, and the pawl 50 form an inflow space S for the gas discharged from the gas generator 34.

The center portion 51 of the pawl has a columnar shape and is rotatably held by the recess 41 of the rotor 40. Therefore, the recessed portion 41 is formed such that both sandwiching surfaces have an arcuate cross section. The pawl claw portion 52 is the engagement means 20.
It is formed so as to project from the central portion 51 into the rotor 40 so that it can be engaged with the engaging teeth 22 of. The pawl portion 52 is normally urged by a spring 42 provided on the rotor 40 so as not to engage with the engaging teeth 22. The pawl leg portion 53 is formed so as to abut the cylindrical inner wall surface 31 of the casing 30 so as to project from the center portion 51 to the outside of the rotor 40. The leg portion 53 is formed in an arc shape around the rotation center C of the pawl 50 so that the leg portion 53 always contacts the cylindrical inner wall surface 31 of the casing 30 when the pawl 50 rotates.

When the gas generator 34 is activated in an emergency, gas is supplied to the inflow space S. The gas flowing into the casing 30 through the gas inlet 35 is blocked by the restriction wall 36 and the outer wall of the rotor 40, so that the gas pressure is applied to the pawl leg portion 53. Then, as shown in FIG. 3, the pawl 50 rotatably supported by the rotor 40 rotates counterclockwise in FIG. 3 against the urging force of the spring 42, and the rotor 40 moves as shown in FIG. Rotate counterclockwise of the pawl claw 52
Engages with the engaging teeth 22 of the engaging means 20. When the pawl leg portion 53 is formed in an arc shape with the center of rotation C of the pawl 50 as the center, the pawl leg portion 53 always contacts the cylindrical inner wall surface 31 of the casing 30 when the pawl 50 rotates.
Gas tightness can be maintained.

Further, due to the pressure applied to the leg portion 53 of the pawl 50, the engaging means 20 engaged with the pawl 50 cooperates with the rotation of the rotor 40 to rotate the engaging means 20 in the counterclockwise direction in FIG. Direction). And the engaging means 20
Is connected to the take-up shaft 11 for winding the webbing 12, so that the webbing 12 is kept until the pawl 50 comes close to the wall surface of the restriction wall 36 opposite to the inflow space S, as shown in FIG. It will be wound around the winding shaft 11. A gas vent hole 37 is formed in the side wall of the casing 30 for venting gas between the leg portion 53 of the pawl 50 and the wall surface of the restriction wall 36 opposite to the inflow space S.

As described above, according to the present invention, first, the pawl 50 is engaged with the engaging means 20 by gas pressure to connect the take-up shaft 11, and then the take-up shaft 11 is rotated to wind the webbing 12. I try to tighten it. After the webbing 12 is tightened, the pulling-out of the webbing 12 may be prevented by a known ELR (emergency lock retractor) or ALR (automatic lock retractor) locking mechanism.

[0023]

The present invention is configured as described above. First, the pawl is engaged with the engaging means by the gas pressure and connected to the take-up shaft, so that the rotor does not idle and the take-up shaft for webbing does not rotate. Can be rotated, and a sufficient amount of webbing can be wound up in an emergency. In particular, when the rotor can rotate the take-up shaft only about one rotation, the take-up loss due to the idling of the rotor significantly reduces the take-up amount. However, in the present invention, the rotation amount of the rotor and the take-up shaft rotation. Since the amount can be made almost the same, the winding efficiency is also good.
Further, even if the pawl rotates, the pawl leg portion is always in contact with the inner wall surface of the cylinder of the casing to maintain airtightness, so that the efficiency loss due to gas leakage can be minimized.

[Brief description of drawings]

FIG. 1 is a side sectional view of a main part of the apparatus.

FIG. 2 is a front view of the inside of the device.

FIG. 3 is a front view showing an engaged state of a clutch mechanism inside the device.

FIG. 4 is a front view of the inside of the apparatus when the webbing tightening is completed.

[Explanation of symbols]

 11 winding shaft 12 webbing 20 engaging means 30 casing 31 cylindrical inner wall surface 34 gas generator 35 gas inlet 36 restriction wall 40 rotor 50 pawl 52 pawl claw 53 pawl leg C rotation center of pawl

Claims (2)

[Claims] 1. A winding shaft that is urged to rotate in the webbing winding direction, a casing having a cylindrical inner wall surface that is concentric with the winding shaft, and a winding shaft that is disposed in the casing and is connected to the winding shaft. Engaging means that rotates integrally with the take-up shaft, a rotor that is disposed between the casing and the engaging means, is concentric with the take-up shaft, and is rotatably supported by the casing, and is rotatably supported by the rotor. And a regulating wall that regulates the gas flow direction by substantially abutting the rotor outer wall surface on the cylindrical inner wall surface of the casing in the vicinity of the gas flow inlet. And a pawl portion projecting into the rotor and engageable with the engaging means, and a leg portion projecting outside the rotor and abutting the cylindrical inner wall surface of the casing. Pretensioner. 2. The pretensioner for a seat belt device according to claim 1, wherein the pawl leg portion is formed in an arc shape having a center of rotation of the pawl as a center.