JP5296661B2 - Coolant discharging device for airbag and airbag device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coolant releasing apparatus for an airbag preventing leakage of a coolant, and also to provide airbag equipment including the same. <P>SOLUTION: The coolant releasing apparatus 100 for the airbag includes: a cylinder 110 where the coolant C is sealed; pistons 120, 130 for sealing the coolant between the inner circumferential surface of the cylinder and them; a gas supplying device 140 for supplying gas for releasing the coolant into the cylinder; and a coolant releasing hole 112 formed at the cylinder and releasing the coolant. The piston has first and second slidable contact surfaces slidably contacting with the inner circumferential surface of the cylinder and arranged apart in an axial direction and a small diameter part arranged between the first and second slidable contact surfaces, and a parting line of a die during forming is arranged in a circumferential direction at the outer circumferential surface of the small diameter part. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a coolant discharge device that discharges a coolant into an airbag of a vehicle such as an automobile and adjusts the internal pressure of the airbag, and an airbag device having such a coolant discharge device.

  The airbag device is provided in a vehicle such as an automobile, and is formed in a bag shape by a base fabric panel. The airbag device is provided with an airbag that expands and expands when a gas for deployment is blown and restrains a passenger. In such an airbag apparatus, it is required to appropriately control the internal pressure of the airbag in order to reduce the acceleration peak experienced by the occupant while deploying the airbag early. For example, it has been proposed to reduce the acceleration received by the occupant by setting the internal pressure to a relatively high value immediately after the collision in order to deploy the airbag early and then reducing the pressure when the occupant is restrained.

  Conventionally, for the purpose of reducing the internal pressure of an airbag to an appropriate pressure after deployment and inflation, it is common to provide exhaust means such as vent holes in the airbag and tune the characteristics depending on the number and arrangement of the exhaust means. there were.

Conventionally, it has been proposed to cool the airbag deployment gas to prevent high-temperature gas from being ejected from a vent hole or to reduce the internal pressure of the airbag to an appropriate pressure. .
For example, Patent Document 1 describes an automobile airbag module that lowers the gas temperature by bringing a coolant such as water into direct contact with a high-temperature gas generated by a gas generator.
Patent Document 2 describes that a cooling device that discharges a coolant into the airbag is provided adjacent to the gas generator. The cooling device includes a reservoir in which the coolant is stored and an operating device that applies an excessive pressure in the reservoir to open the outlet and discharge the coolant.

Special table 2009-511327 Special table 2009-528211

If the liquid coolant is released at a predetermined timing during or after the airbag is inflated, the deployment gas is cooled by the heat of vaporization of the coolant to reduce the internal pressure of the airbag, resulting in good occupant restraint performance. Can be obtained.
As such a coolant discharge device, for example, a coolant such as antifreeze liquid is sealed inside a cylindrical cylinder by a piston such as silicon rubber, and the piston is pressed using a gas generated by a micro gas generator (MGG). Some have been proposed that release coolant.

The coolant discharge device needs to be held so that the coolant does not leak over the life of the vehicle (for example, 10 years or more as an example). As described above, when the coolant is sealed between the inner circumferential surface of the cylinder and the outer surface of the rubber piston, for example, when a spherical or cylindrical piston is used, the mold for molding the piston with a two-part mold is used. There is a concern that the burr formed on the parting line (parting line) of the mold will be applied to the sliding contact portion with the cylinder, a minute gap is formed, the sealing performance is impaired, and the coolant leaks. The Further, it is conceivable to remove such burrs and smoothen the sliding contact surface with the cylinder, but in this case, the deburring operation becomes complicated and the cost of the piston increases.
An object of the present invention is to provide a coolant release device for an airbag that can prevent leakage of the coolant, and an airbag device including such a coolant release device.

In order to solve the above-described problem, the air bag coolant discharge device of the present invention is formed of a cylinder formed with a cylinder filled with a coolant discharged inside the air bag, and an elastic material, A piston that is inserted into the cylinder and seals the coolant between the inner peripheral surface of the cylinder, and a coolant discharge gas supply device that supplies the coolant discharge gas to the inside of the cylinder and drives the piston And a coolant discharge device for an airbag that is formed in the cylinder and from which the coolant pressed by the piston is discharged, the piston having an inner peripheral surface of the cylinder It is provided between the first and second sliding contact surface portions and the first and second sliding contact surface portions that are slidably contacted over the entire circumference and spaced apart in the axial direction of the cylinder. , And a first and a small diameter portion formed smaller in diameter than the second sliding surface, a parting line of the mold at the time of molding as well as arranged along the circumferential direction on the outer peripheral surface of the small diameter portion A pair of cylinders spaced apart from each other in the longitudinal direction of the cylinder, and the coolant is held at a position away from the coolant discharge hole in a state of being enclosed in a space between the pair of pistons. When driven by the discharge gas, it moves to the position where the coolant discharge hole is provided, and is discharged by the pressure received from the piston .
In addition, in this specification, a claim, etc., a sliding contact shall point out the state which is contacting in the slidable state.

According to the present invention, since the parting line is provided in the small diameter portion provided between the first and second sliding contact surface portions, the burr is not disposed on the sliding contact surface portion with the cylinder.
As a result, the contact state between the inner peripheral surface of the cylinder and the piston can be improved, and the deterioration of the sealing performance due to burrs and the accompanying leakage of the coolant can be prevented.
In addition, the coolant can be sealed in the unused state and the coolant can be discharged during use without providing any particular blocking means in the coolant discharge hole.

In this invention, it can be set as the structure by which the slope part which a diameter changes gradually along the axial direction of the said piston is formed between the said 1st and 2nd sliding contact surface part of the said piston, and the said small diameter part. .
In the present invention, when removing the piston from the mold, so-called forced extraction is performed by pulling out the piston while deforming it. By providing such a slope portion, it is easy to remove from the mold, and the piston is damaged. Can also be prevented.

In this invention, the said 1st and 2nd sliding contact surface part of the said piston can be set as the structure which is a spherical convex surface.
According to this, even if a slight inclination of the piston with respect to the cylinder occurs, the change in the contact state between the cylinder and the piston is suppressed, and the sealability of the coolant can be ensured.

  The airbag device of the present invention includes an airbag that is formed in a bag shape and that is deployed and inflated by blowing a deployment gas therein, and a deployment gas supply that supplies the deployment gas to the interior of the airbag. And an air bag coolant discharge device that discharges the coolant into the airbag during or after deployment.

  As described above, according to the present invention, it is possible to provide an airbag coolant discharge device capable of preventing leakage of the coolant and an airbag device including such a coolant discharge device.

It is a schematic diagram which shows the structure of the airbag apparatus which has embodiment of the coolant discharge | release apparatus to which this invention is applied. It is sectional drawing of the refrigerant | coolant discharge | release apparatus of embodiment, Comprising: The cross section cut by the plane containing the central axis of a cylinder is shown. 2A shows an unused state, FIG. 2B shows a state immediately after the start of driving of the piston, and FIG. 2C shows a state in which the coolant is being discharged. It is a side view of the piston in the coolant discharge device of an embodiment. It is typical sectional drawing which shows the structure of the metal mold | die which shape | molds the piston of FIG.

Hereinafter, an embodiment of a coolant discharge device and an airbag device to which the present invention is applied will be described.
The airbag device of the embodiment is provided in an automobile such as a passenger car, for example. The application part of the airbag device is not particularly limited.For example, a driver's seat airbag provided at the boss portion of the steering wheel, a passenger seat airbag provided at the dashboard, a passenger's knee provided at the lower part of the dashboard, etc. It is used as a knee bag to be restrained, a side airbag provided on the side of the seat, a curtain airbag deployed in a curtain shape along the side window, and the like. In addition, the shape, arrangement | positioning, etc. of each structural member are suitably changed according to an application location.

As shown in FIG. 1, the airbag device 1 includes an airbag 10, a retainer 20, an inflator 30, a coolant discharge device 100, and the like.
The airbag 10 is formed in a bag shape by stitching a plurality of panels formed by cutting a nylon or polyester base fabric, for example. The airbag 10 is housed inside the retainer 20 in a folded state when not in use (before a collision).
In the event of a collision, the airbag 10 is deployed and inflated in the cabin of the vehicle by introducing the gas for deployment generated by the inflator 30, and restrains a passenger (not shown).

The retainer 20 is a container-like part in which the airbag 10 before deployment and inflation is accommodated. Further, the retainer 20 is provided with an inflator 30 and a coolant discharge device 100.
The inflator 30 is a deployment gas supply device that generates a high-temperature deployment gas that deploys and inflates the airbag 10 based on a signal from an airbag control unit (not shown). The inflator 30 includes a gas generating agent that generates nitrogen gas or the like during combustion, and an igniter that ignites the gas generating agent via an igniting agent.

The coolant discharge device 100 releases a liquid coolant such as antifreeze into the deployment gas in the airbag 10 in response to a signal from the airbag control unit during or after the airbag 10 is deployed or inflated. Then, the internal pressure of the airbag 10 is reduced.
As shown in FIG. 2, the coolant discharge device 100 includes a cylinder 110, a first piston 120, a second piston 130, a micro gas generator (MGG) 140, and the like.

The cylinder 110 is formed in a substantially cylindrical shape using a metal such as steel.
One end of the cylinder 110 is substantially closed by an end surface 111 formed integrally with the main body.
A nozzle 112 is formed on the outer peripheral surface near the end on the end surface 111 side of the cylinder 110. The nozzle 112 functions as a coolant discharge hole that discharges the coolant C. The nozzle 112 is formed as a nozzle having a tapered hole shape, for example, so that the coolant C can be ejected (sprayed) as the spray S.
At the end opposite to the end surface 111 of the cylinder 110, a mount portion 113 is formed which has a diameter larger than that of the other portion and is attached to the MGG 140.

The first piston 120 and the second piston 130 are inserted on the inner diameter side of the cylinder 110 and hold a liquid coolant C such as antifreeze liquid therebetween. Further, the first piston 120 and the second piston 130 have a function of transporting and pressurizing the coolant C to an area where the nozzle 112 is provided and ejecting the nozzle 112 from the nozzle 112 when the coolant discharging device 100 is operated.
Since the first piston 120 and the second piston 130 are common parts, the first piston 120 will be described below with reference to FIG. 3 as a representative.

  The first piston 120 is integrally formed of an elastic material such as silicon rubber. As shown in FIG. 3, the first piston 120 includes a first sliding contact surface portion 121, a second sliding contact surface portion 122, a small diameter portion 123, tapered surface portions 124 and 125, chamfered portions 126 and 127, end surfaces 128 and 129, and the like. Is formed.

The first slidable contact surface portion 121 and the second slidable contact surface portion 122 are provided on the outer peripheral surface portion of the first piston 120 so as to extend in the circumferential direction. The first slidable contact surface portion 121 and the second slidable contact surface portion 122 are in contact with the inner peripheral surface of the cylinder 110 over the entire circumference. Sometimes it is a surface portion that slides with the inner peripheral surface of the cylinder 110. The first slidable contact surface portion 121 and the second slidable contact surface portion 122 are arranged apart from each other in the central axis direction of the first piston 120 (the central axis direction of the cylinder 110).
Further, the surfaces of the first slidable contact surface portion 121 and the second slidable contact surface portion 122 are formed as convex surfaces substantially along a spherical surface having a center on the central axis of the first piston 120.

The small diameter portion 123 is a cylindrical portion that is provided at an intermediate portion between the first sliding contact surface portion 121 and the second sliding contact surface portion 122 and connects them.
The outer diameter of the small diameter portion 123 is set smaller than the outer diameters of the first sliding contact surface portion 121 and the second sliding contact surface portion 122 so that the outer peripheral surface of the small diameter portion 123 does not contact the inner peripheral surface of the cylinder 110. It has become. The difference in radius between the first sliding contact surface portion 121 and the second sliding contact surface portion 122 and the small diameter portion 123 (groove depth in the outer peripheral surface of the first piston 120) is generated in the small diameter portion 123 along the dividing line of the mold. Even if the burrs protrude from the contact surfaces of the first slidable contact surface portion 121 and the second slidable contact surface portion 122 on the outer diameter side, even if the burrs contact the inner surface of the cylinder 110, the sealing performance is substantially reduced. For example, the thickness may be set to about 0.5 to 1 mm although it depends on the hardness of the material.

The tapered surface portions 124 and 125 are provided between the small diameter portion 123 and the first sliding contact surface portion 121 and between the small diameter portion 123 and the second sliding contact surface portion 122, respectively.
The tapered surface portions 124 and 125 are formed so that the outer diameter gradually increases from the small diameter portion 123 side to the sliding contact surface portions 121 and 122 side. In the cross section obtained by cutting the first piston 120 in the radial direction, an angle formed by the surfaces of the tapered surface portions 124 and 125 with respect to the central axis direction of the first piston 120 is set to, for example, about 45 degrees.
Further, the boundary portion (corner portion) between the tapered surface portions 124 and 125 and the small diameter portion 123 is rounded.

  The chamfered portions 126 and 127 are provided at both end portions in the central axis direction of the first piston 120. The chamfered portions 126 and 127 are formed in a tapered shape by applying so-called corner chamfering (C chamfering) to the end portions of the first sliding contact surface portion 121 and the second sliding contact surface portion 122.

The end surfaces 128 and 129 are provided at both ends in the central axis direction of the first piston 120, respectively, and are formed in a planar shape perpendicular to the central axis.
The interval between the end faces 128 and 129 is set to be approximately the same as the inner diameter of the cylinder 110, for example, in order to prevent the first piston 120 from tilting with respect to the cylinder 110.

As shown in FIG. 4, the 1st piston 120 is shape | molded using a pair of metal mold | die M1 and M2 comprised by 2 parts. In FIG. 4, the gate, the eject pin, etc. are not shown.
The mold M1 is formed with a cavity C1 for molding the first sliding contact surface portion 121, the tapered surface portion 124, the chamfered portion 126, the end surface 128, and the intermediate portion of the small diameter portion 123.
A cavity C <b> 2 is formed in the mold M <b> 1 to mold the second sliding contact surface portion 122, the tapered surface portion 125, the chamfered portion 127, the end surface 129, and the middle portion of the small diameter portion 123.
The dividing lines (parting lines) PL of the molds M1 and M2 are arranged to extend in the circumferential direction at an intermediate portion of the small diameter portion 123 of the first piston 120.

The MGG 140 is a coolant supply gas supply device that generates a coolant discharge gas using, for example, explosives and drives the piston 122.
The MGG 140 is formed in a substantially columnar shape, and is inserted and fixed inside a holder 141 formed in a substantially cylindrical shape.
The holder 141 is inserted into the mount portion 113 of the cylinder 110. The holder 141 is fixed to the cylinder 110 while holding the MGG 140 by crimping the opening end of the mount portion 113.

The MGG 140 ignites in response to a signal from the airbag control unit and generates a coolant discharge gas.
When the cooling gas is generated from the MGG 140, as shown in FIG. 2B, the first piston 120 and the second piston 130 are displaced toward the end face 111 side by the gas pressure with the coolant C interposed therebetween. After the second piston 130 comes into contact with the end surface 111, only the first piston 120 is displaced, so that the interval between the first piston 120 and the second piston 130 is narrowed as shown in FIG. Thus, the storage space for the coolant C is reduced, and the coolant C is discharged as the spray S from the nozzle 112.

According to the coolant discharge device 100 and the airbag device 1 of the embodiment described above, the following effects can be obtained.
(1) The first sliding contact is made by arranging the dividing line PL of the molds M1, M2 in the small diameter portion 123 where the burr does not substantially affect the sealing performance with the inner peripheral surface of the cylinder 110. Since there are no burrs on the surfaces of the surface portion 121 and the second slidable contact surface portion 122, no gap due to burrs is formed between each slidable contact surface portion and the cylinder 110. Accordingly, the leakage of the coolant C can be prevented.
(2) The first piston 120 is provided between the first sliding contact surface portion 121, the second sliding contact surface portion 122, and the small diameter portion 123 by providing tapered surface portions 124 and 125 in which the diameter of the first piston 120 gradually changes. Can be easily removed from the molds M1 and M2 by so-called forced removal, and damage to the first piston 120 can be prevented. For this reason, it is not necessary to perform an undercut process using an expensive and complicated slide mold or the like.
Further, by rounding the boundary portion between the tapered surface portions 124 and 125 and the small diameter portion 123, it is possible to further easily remove the force.
(3) Since the first sliding contact surface portion 121 and the second sliding contact surface portion 122 are spherical convex surfaces, even if a slight inclination of the first piston 120 with respect to the cylinder 110 occurs, The change in the contact state with the first piston 120 is suppressed, and the sealing property of the coolant C can be ensured.
(4) Since the chamfered portions 126 and 127 are formed at both ends of the first piston 120, when the first piston 120 is inserted into the cylinder 110, the chamfered portions 126 and 127 cause the first piston 120 to move relative to the cylinder 110. Centering can be facilitated.
(5) Since both end portions of the first piston 120 are flat end surfaces 128 and 129, the axial length of the first piston 120 is shortened, and the cylinder 110 is shortened while ensuring the capacity of the coolant C. Can be planned.
In addition, the effect regarding the 1st piston 120 demonstrated above can be acquired also in the 2nd piston 130 which shares components.
(6) The first piston 120 and the second piston 130 hold the coolant C at a distance from the nozzle 112 and are driven by the coolant discharge gas so as to remove the coolant C from the nozzle 112. With the configuration in which the nozzle 112 is conveyed and discharged, it is possible to seal the coolant C in an unused state and discharge the coolant C in use without providing a blocking means in the nozzle 112. .

Note that the technical scope of the present invention is not limited by the above-described embodiments, and the configurations of the coolant discharge device and the airbag device can be appropriately changed, and each member constituting the airbag device. The shape, structure, arrangement, etc. can be changed as appropriate.
For example, in the piston of the embodiment, the slidable contact surface portion is a spherical convex surface, but the present invention is not limited to this and may have other shapes. Further, the angle of the tapered surface portion and the rounding method can be appropriately changed. Further, the material is not limited to the silicon rubber of the embodiment. Furthermore, the shape of the end surface is not limited to a flat surface as in the embodiment, and may be a convex curved surface or a concave curved surface, for example.
Further, the coolant discharge device of the embodiment is of a type that holds the coolant between a pair of pistons. However, the present invention is not limited to this, and, for example, one piston is used and a coolant discharge hole is used. Can also be applied to those that are closed by other closing means.
Further, a plurality of the coolant discharge devices of the present invention may be provided for one airbag device, and the operation timing and the number of operations may be changed according to the collision situation, the occupant's physique, position, and the like. Also, the number of coolant discharge holes provided in one coolant discharge device and the discharge direction are not limited.

DESCRIPTION OF SYMBOLS 1 Airbag apparatus 10 Airbag 20 Retainer 30 Inflator 100 Coolant discharge apparatus 110 Cylinder 111 End surface 112 Nozzle 113 Mount part 120 1st piston 121 1st sliding surface part 122 2nd sliding surface part 123 Small diameter part 124,125 Tapered surface part 126 , 127 Chamfered portion 128, 129 End surface 130 Second piston 140 Micro gas generator (MGG)
141 Holder C Coolant S Spray M1, M2 Mold C1, C2 Cavity PL Dividing line

Claims (4)

A cylinder formed in a cylindrical shape and filled with a coolant discharged into the airbag;
A piston that is formed of an elastic material and is inserted into the cylinder and seals the coolant between the cylinder and an inner peripheral surface;
A coolant discharge gas supply device for supplying a coolant discharge gas into the cylinder and driving the piston;
A coolant discharge device for an air bag, comprising: a coolant discharge hole formed in the cylinder and from which the coolant pressed by the piston is discharged;
The piston is slidably contacted with the inner peripheral surface of the cylinder over the entire circumference, and is separated from the first and second slidable contact surface portions arranged in the axial direction of the cylinder, and the first and second slidable contacts. A small-diameter portion that is provided between the surface portions and has a smaller diameter than the first and second sliding contact surface portions, and a parting line of the mold at the time of molding is formed around the outer peripheral surface of the small-diameter portion. A pair is provided along the direction and spaced apart in the longitudinal direction of the cylinder,
The coolant is held at a position away from the coolant discharge hole in a state of being enclosed in a space between the pair of pistons, and the piston is driven by the coolant discharge gas, thereby the coolant discharge hole. The air bag coolant discharge device is moved to a position where the air bag is provided and discharged by pressure received from the piston . 2. The inclined portion whose diameter gradually changes along the axial direction of the piston is formed between the first and second sliding contact surface portions of the piston and the small diameter portion. Coolant discharge device for airbags. The air bag coolant discharge device according to claim 1 or 2, wherein the first and second sliding contact surface portions of the piston are spherical convex surfaces. An airbag that is formed in a bag shape and is expanded and inflated by blowing a gas for deployment inside;
A deployment gas supply device for supplying the deployment gas into the airbag;
An airbag device comprising: the airbag coolant release device according to any one of claims 1 to 3 , wherein the coolant is discharged into the airbag during deployment or after deployment.

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