KR20160042588A - Seat belt pretensioner apparatus for vehicle - Google Patents

Abstract

Provided is a seat belt pretensioner apparatus for a vehicle. The pretensioner apparatus comprises: a gas generator generating gas; a tube communicating with the gas generator; a piston body fixedly installed in the tube in the downstream part of the gas generator and having a gas hole through which gas passes, formed in the central portion thereof; a piston inserted into the gas hole and moving by being pushed by gas supplied from the gas generator; a plurality of balls provided in the tube so as to move by being pushed by the piston; and a gear member having a plurality of ball grooves formed on the outer circumferential surface thereof so as to be engaged with the balls. The present invention can prevent an overshoot phenomenon by removing residual gas remaining in the tube through the configuration.

Description

[0001] SEAT BELT PRETENSIONER APPARATUS FOR VEHICLE [0002] BACKGROUND OF THE INVENTION [0003]

The present invention relates to a vehicle seat belt pretensioner device capable of preventing an overshoot phenomenon.

 Generally, a seat belt installed on a vehicle is configured to restrain the occupant's body in the event of a vehicle collision to prevent secondary collision and to alleviate shock, while preventing the occupant from jumping out of the vehicle. The most common form is a three-point seat belt, which is a combination of shoulder restraint shoulder belts and waist restraint lap belts.

Such a seat belt has proven high stability in the event of a vehicle collision, and is becoming an absolutely necessary device for the safety of an occupant. In recent years, a locking device has been developed in which a seat belt can be adjusted to an optimal restraining height according to body conditions, or a limitation is imposed on activities while reducing the damage of an occupant in an accident.

In recent years, a retractor pretensioner device is added to such a seat belt to rewind the belt in the event of a vehicle collision, so that the occupant is brought into close contact with the seat.

In this way, when the vehicle collides, the seat belt is instantaneously rewound so that the occupant is closely fixed to the seat, thereby minimizing the distance that the occupant moves by inertia. As a result, it is possible to minimize the possibility of injury of the occupant, which may occur inside the vehicle.

The pretensioner device is typically a rack-pinion type using racks and pinions, as well as gear rotating by balls.

The ball type pretensioner apparatus includes a gas generator for generating gas, a cylinder to which a gas generated from the gas generator is supplied, a piston provided in the cylinder and pushed by gas pressure, a plurality of balls accommodated in the cylinder and pushed by the piston, And a gear coupled to the spool and rotated by engagement with the moving balls.

However, in such a ball type pretensioner, the gas can not completely escape from the inside of the cylinder during operation, and residual gas exists in the cylinder. In this case, when the load limiter operates, an overshoot phenomenon occurs in which the initial load of the seat belt is instantaneously greatly increased by the pressure of the residual gas in the cylinder. In order to prevent this, there is a problem that the initial binding force is lowered when the vent hole is formed in the cylinder.

The load limiter is a device for relieving the shock by releasing a certain amount of the seat belt by rotating the torsion bar in the safety device when the load applied to the seat belt becomes a certain value or more in order to minimize the impact between the seat belt and the passenger.

US2014 / 0158805 US2011 / 0062267

It is an object of the present invention to provide a seat belt pretensioner device for a vehicle which improves overshoot prevention and performance.

According to an embodiment of the present invention, there is provided a gas generator including a gas generator for generating gas, a tube communicating with the gas generator, a piston body fixedly installed in the tube downstream of the gas generator and having a gas hole through which the gas passes, A piston inserted into the gas hole and pushed by the gas supplied from the gas generator, a plurality of balls provided in the tube to be pushed by the piston, and a plurality of ball holes There is provided a vehicular seat belt pretensioner apparatus including a gear member formed with a seat belt.

The piston may have a cross-sectional length less than the outer diameter of the balls.

The pretensioner device may further include sealing means for sealing a gap between the piston body and the inner circumferential surface of the tube.

The piston body may have a ball shape, and the sealing means may include an o-ring provided on the outer periphery of the piston body.

The tube may include a restricting portion that restrains the piston body to a predetermined position.

The piston body may include a fitting portion that is inserted into the inner circumferential surface of the tube at a predetermined position and a hook portion that is formed at a rear end portion of the fitting portion and is engaged with the step portion of the tube.

Wherein the piston is inserted into the gas hole of the piston body; And a ball contact portion formed in a hemispherical shape at one end of the insertion portion and contacting the ball.

According to an embodiment of the present invention, the gas generated from the gas generator may be formed to have a predetermined pressure so that a high-pressure gas may be delivered to the piston.

According to one embodiment of the present invention, it is possible to solve the overshoot phenomenon by eliminating the presence of residual gas in the cylinder, and to improve the performance of the pretensioner apparatus.

1 is a perspective view showing a state in which a vehicle seat and a seat belt assembly are coupled to each other.
2 is a perspective view showing a configuration of the seat belt assembly of FIG. 1;
3 is a perspective view showing a configuration of the retractor assembly of FIG. 2;
4 is a side cross-sectional view showing a configuration of a pretensioner according to an embodiment of the present invention.
5 is a partially enlarged view of Fig.
Fig. 6 is an exploded perspective view showing the configuration of Fig. 5. Fig.
7 is an exploded perspective view showing a configuration of a gas hole of the piston body of FIG.
8 is a partial side sectional view showing the state before the gas generator of Fig. 4 is operated.
9 is a partial side sectional view showing the state after the gas generator of Fig. 4 is operated.
10 is a partially enlarged side sectional view of a pretensioner according to another embodiment of the present invention.
11 is an exploded perspective view showing the configuration of Fig.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. It will be apparent to those skilled in the art that the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, It is provided to let you know.

1 is a perspective view showing a state in which a vehicle seat and a seat belt assembly are coupled to each other.

1 shows a vehicle seat 10 and a seat belt assembly 12. The seat belt assembly 12 includes a seat belt 14 having a shoulder belt portion 16 extending from the buckle loop 20 from the upper anchorage 18 and a seat belt 14 extending from the buckle loop 20 to the anchor point 24 And a lap belt portion 22. The buckle latch plate 26 can be inserted into the seat belt buckle 28 to be locked and released to the seat belt assembly 12. [ The seat belt buckle cable 30 directly or in cooperation with other components secures the seat belt buckle 28 to a portion of the vehicle frame.

The seat belt 14 can be released from the retractor assembly 32 located in the vehicle seat 10 or structurally connected to the vehicle body to adjust the effective seat belt length. When the buckle latch plate 26 is fastened to the seat belt buckle 28, the seat belt assembly 12 forms three points between the upper anchorage 18, the buckle latch plate 26, and the anchor point 24 do. Other suitable configurations, such as positions for other retractor assemblies 32, buckle latch plate 26, and anchor points 24 may be used.

2 is a perspective view showing a configuration of the seat belt assembly of FIG. 1;

Referring to Figure 2, the retractor assembly 32 includes a spool assembly 34 and a gas generator 36 (see Figure 3) mounted to the common frame 38. The spool assembly 34 is connected to the seat belt 14 to seat the seat belt 14 of the shoulder belt portion 16. The end portion of the lap belt portion 22 of the seat belt 14 is fixedly connected to an anchor point, for example, another portion of the vehicle, for example, the seat 10.

3 is a perspective view showing a configuration of the retractor assembly of FIG. 2;

3, the spool assembly 34 connects the shoulder belt portion 16 of the seat belt 14 and rotates the seat belt 14 to wind-up or pay-out. A torsional type spring is received within the spring end cap 42 and rotatably urges the spool assembly 34 to retract the seat belt 14.

During normal operation of the vehicle, the retractor assembly 32 allows the seat belt 14 to be released so as to give the occupant a certain amount of freedom of movement. However, if a collision or potential conflict condition is detected, the retractor assembly 32 is locked to prevent unwinding of the seat belt 14 and to restrain the occupant to the seat 10. For example, when the vehicle is suddenly decelerated at a predetermined rate or when the brake is operated with a predetermined force, the retractor assembly 32 is locked.

The retractor assembly 32 further includes a pretensioner device 40 connected to rotate the spool assembly 34 for pretensioning.

The pretensioner device 40 winds the seat belt 14 in a state in which it is more tightly fastened to the occupant in the initial stage of a vehicle collision. As a result, the occupant reduces the movement or protrusion of the occupant to the front of the vehicle due to the deceleration force of the vehicle collision or rollover.

The vehicle includes sensors that send signals indicating dangerous situations such as vehicle crashes, rollovers, and the like. An electronic control device, for example, a central processing unit or other controller receives the signal and controls the seat belt assembly 12 so that the seat belt 14 of the vehicle is tightened.

4 is a side cross-sectional view showing a configuration of a pretensioner according to an embodiment of the present invention.

Quot; upstream " and " downstream " along the flow direction of the gas generated from the gas generator in the following description.

4, the pretensioner device 40 includes a gas generator 41, a tube 43, a piston body 45, a piston 47, a ball 48, and a gear member 49.

The gas generator 41 is used to provide an inflation gas in response to an ignition signal.

The tube 43 is configured to communicate with the gas generator 41, and the gas generated from the gas generator 41 is supplied into the tube 43. In one embodiment, the gas generator 41 is connected to one end of the tube 43.

The piston body 45 is stationarily installed inside the tube 43 and is located on the downstream side of the gas generator 41.

The piston 47 is fixed to the piston body 45 and is configured to protrude from the piston body 45 by the gas generated from the gas generator 41.

A plurality of balls 48 are forced in the tube 43 by the piston 47 and move along the actuation path of the tube 43. The moved ball 48 is engaged with a ball seat 49a formed on the outer periphery of the gear member 49 to rotate the gear member 49.

The gear member 49 is rotatably provided around the shaft A and a ball seat 49a is formed on the outer periphery of the gear member 49 to form a substantially hemispherical groove for receiving the balls 48. [

As the balls 48 move through the tube 43, the gear member 49 rotates about the axis A. As the balls 48 engage with the gear member 49, the gear member 49 is rotated by the inflation gas in the direction of the arrow to rotate the spool assembly 34 (see FIG. 3), and pretensioning is performed.

5 is a partially enlarged view of Fig. Referring to FIG. 5, the gas generator 41 is installed at one end of the tube 43.

The piston body 45 is fixedly installed at a predetermined position in the tube 43. To this end, the tube 45 is provided with a restricting portion for restricting one end of the piston body 45. The restricting portion may include, for example, a recessed portion 43a recessed toward the inside of the tube 45. [ The recessed portion 43a may be formed in a substantially circular shape along the circumferential direction of the tube 43. In other embodiments, the recess 43a may be formed at regular intervals along the circumferential direction of the tube 43.

The piston body 45 may be formed in a substantially spherical shape with both ends thereof cut off. The piston body 45 has a gas hole 54a formed therethrough. The piston body 45 may include a metallic material, such as an aluminum material.

The pretensioner device 40 may further include sealing means for sealing the gap between the piston body 45 and the tube 43. The sealing means includes an o-ring (46) provided on the outer circumferential surface of the piston body (45) to block the gap between the piston body (45) and the tube (43).

With this configuration, the gas supplied from the gas generator 41 stays in the chamber C between the piston body 45 and the gas generator 41 for a predetermined time, so that the gas is constantly pressurized. The piston 47 is inserted into the gas hole 54a and is configured to be pressurized by the gas generated from the gas generator 41 and to protrude from the piston body 45 to the downstream side.

The piston 47 is formed so that the length of its cross section is smaller than the inner circumferential surface of the tube 43 so that a relatively large amount of gas can pass between the piston 47 and the inner circumferential surface of the tube 43. The piston 47 may, for example, comprise a metallic material such as steel.

The piston 47 may be formed to be approximately equal to or smaller than the outer diameter of the balls 48. With this configuration, gas can flow quickly and smoothly along the passage of the tube 41. [

As a result, residual gas is not present in the tube 43, and overshoot phenomenon in which the initial load of the seat belt 14 instantly increases during the load limiter operation can be reduced.

The residual gas does not exist in the tube 43 and it is not necessary to provide a separate safety valve device for discharging gas to the tube.

FIG. 6 is an exploded perspective view illustrating the configuration of FIG. 5, and FIG. 7 is an exploded perspective view illustrating the piston configuration of FIG.

6 and 7, the piston body 45 is formed with a gas hole 45a through which the gas passes and into which the piston 47 is inserted. At least one pressing protrusion 45c is provided on the inner circumferential surface of the gas hole 45a so as to be pressed against the outer peripheral surface of the piston 47. [ The pressure projection 45c prevents the piston 47 from being disengaged from the gas hole 45a when the gas supply is not performed.

A substantially circular groove 45b is formed on the outer periphery of the piston body 45. And the O-ring 46 is fitted into the groove 45b. The piston 47 is formed into a substantially cylindrical shape with both ends closed.

Next, the process of moving the piston 47 of the pretensioner device 40 constructed as described above will be described.

8 is a partial side sectional view showing the state before the gas generator of Fig. 4 is operated.

Referring to Fig. 8, the piston 47 is kept inserted into the gas hole 45a in a state where gas is not supplied from the gas generator 41 into the tube 43. Fig.

9 is a partial side sectional view showing the state after the gas generator of Fig. 4 is operated.

Referring to Fig. 9, the gas is supplied from the gas generator 41 to the chamber C (see Fig. 5). The O-ring 46 provided on the outer periphery of the piston body 45 seals between the piston body 45 and the tube 43. Thus, the gas is pressurized in the chamber C at a constant pressure for a certain period of time. At this time, the piston body 45 does not move to the recessed portion 43 formed in the tube 43 and is located at a predetermined position in the tube 43.

The gas pressurized at a constant pressure in the chamber C flows into the gas hole 45a and pushes one end of the piston 47 in a bumpy manner so that the piston 47 protrudes from the piston body 45.

The protruding piston body 35 pushes the adjacent ball 48 so that the balls 48 move inside the tube 43.

The cross sectional length L of the piston 47 is formed to be smaller than the inner diameter D of the tube 43 or approximately equal to or smaller than the outer diameter of the ball 48 so that a sufficient passage for the gas to pass therethrough is secured. The piston 47 is closed at both ends so that the gas pressure introduced into the gas hole 45a is completely applied to one end of the piston 47 inserted in the piston body 45 to allow the piston 47 to move from the piston body 45 Relatively fast and with greater force to come into contact with the ball 48.

The gas pressurized at a constant pressure in the chamber C instantaneously pushes the piston 46 through the gas hole 45a and flows through the passage 46 secured between the piston 46 and the inner peripheral surface of the tube 43, As shown in FIG. Therefore, all the gas remaining in the tube 43 at a certain point of time is removed. As a result, when the load limiter (not shown) is operated, the overshoot phenomenon in which the initial load is instantaneously greatly increased on the seat belt 14 is solved, and the performance of the pretensioner device can be improved.

FIG. 10 is a partially enlarged cross-sectional side view of a pretensioner according to another embodiment of the present invention, and FIG. 11 is an exploded perspective view showing the configuration of FIG.

The same reference numerals are assigned to the same components as those in FIG. 4, and redundant description is omitted.

10 and 11, the tube 53 may have a double pipe shape including a large diameter portion 53a and a small diameter portion 53c. In this case, a step portion 53e is formed between the large-diameter portion 53a and the small-diameter portion 53c.

The piston body 55 has a fitting portion 55b fitted to the inner circumferential surface of the small diameter portion 53b and a fitting portion 55c extending to one end of the fitting portion 55b and engaged with the step portion 53e of the tube 53 .

The fitting portion 55b of the piston body 55 is in close contact with the inner peripheral surface of the small diameter portion 53b and the engagement portion 55c is in close contact with the step portion 53e. Through this structure, the space between the piston body 55 and the tube 53 is sealed.

The stepped portion 53e serves to fix the piston body 55 to a predetermined position of the tube 53 when supplying gas into the tube 53. [

A gas hole 55a is formed at the center of the piston body 55 and a piston 57 is inserted into the gas hole 55a. The piston 57 includes a ball contact portion 57c formed in a hemispherical shape at one end portion of the insertion portion 57a and in contact with the ball 48. [

The ball contact portion 57c is formed so as to cover the gas hole 55a of the piston body 55 to prevent the gas supplied to the chamber C from leaking at the initial stage of gas supply. Thus, the gas supplied to the chamber C is pressurized to a predetermined pressure.

The ball contact portion 57c of the piston 57 is formed in an approximately hemispherical shape so that it can smoothly contact with the ball 48 and can be more effectively pressed by the gas. That is, the substantially circular surface side is in contact with the ball 48 and the flat surface portion 57e, that is, the surface 57d connected to the insertion portion 57a is pressed by the gas pressure so that the piston 57 And can be moved more smoothly toward the ball 48.

Although the present invention has been described with reference to the accompanying drawings and the preferred embodiments described above, the present invention is not limited thereto but is limited by the following claims. Accordingly, those skilled in the art will appreciate that various modifications and changes may be made thereto without departing from the spirit of the following claims.

40: pretensioner device 41: gas generator
43, 53: tubes 45, 55: piston body
47, 57: Piston 48: Ball

Claims (7)

A gas generator for generating gas;
A tube communicating with the gas generator;
A piston body fixedly installed in the tube downstream of the gas generator and having a gas hole through which the gas passes,
A piston inserted into the gas hole and pushed and moved by the gas supplied from the gas generator;
A plurality of balls disposed in the tube to pivotally move by the piston; And
A gear member having a plurality of ball grooves formed on an outer peripheral surface thereof so as to be engaged with the balls;
Wherein the belt pretensioner device comprises: The method according to claim 1,
Wherein the piston has a cross-sectional length less than an outer diameter of the balls. 3. The method of claim 2,
And sealing means for sealing a gap between the piston body and the inner circumferential surface of the tube. The method of claim 3,
Wherein the piston body has a ball shape,
Wherein the sealing means includes an o-ring provided on the outer periphery of the piston body. The method according to claim 1,
Wherein the tube includes a restricting portion for restraining the piston body to a predetermined position. The method of claim 3,
Wherein the piston body includes a fitting portion to be fitted at a predetermined position on an inner circumferential surface of the tube, and an engagement portion formed at a rear end portion of the fitting portion and hooked to a step portion of the tube. The method according to claim 6,
Wherein the piston is inserted into the gas hole of the piston body; And
And a ball contact portion formed in a hemispherical shape at one end of the insertion portion and contacting the ball.

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