Air bag device

[0001] [Technical field to which the invention belongs] The present invention is an airbag device in which an inflator is housed inside a retainer in which the peripheral edge of the opening of a folded airbag is fixed, and the airbag is deployed by the gas generated by the inflator when a vehicle collides to restrain an occupant. The present invention relates to a device provided with a control valve capable of opening and closing a vent hole formed in the retainer. [0002] [Conventional technology] In a conventional airbag device, a vent hole is provided in an airbag that expands with a gas generated by an inflator, and a part of the gas is discharged from the vent hole to control the internal pressure of the airbag. In such an airbag device, by closing the vent hole with a thin film, the airbag is rapidly expanded at the initial stage of deployment, and when the deployment is completed and the internal pressure of the airbag increases, the thin film breaks and the vent hole. It has been proposed that the occupants are softly restrained by discharging gas from the air bag (see Gazette 5-6206). [0003] In addition, two inflators are provided in the airbag device, and if there is no occupant in the vicinity of the airbag device, both of the two inflators are ignited, and if there is an occupant in the vicinity of the airbag device, It has been proposed that the deployment speed and internal pressure of the airbag are controlled according to the position of the occupant by igniting only one inflator (see JP-A-9-301115). [0004] By the way, in the above-mentioned Jikken No. 5-6206, since the pressure at which the thin film breaks tends to vary, the vent hole is accurately opened when the internal pressure of the airbag reaches a predetermined value. Not only is it difficult, but there is also the problem that precise control of the internal pressure is difficult because the vent hole that was once opened cannot be closed again. In addition, the one described in Japanese Patent Application Laid-Open No. 9-301115 not only requires two inflators, which increases the number of parts and causes a cost increase, but also has two stages of airbag deployment characteristics. There was a problem that fine control was difficult because it could only be controlled. [0005] Therefore, the applicant has proposed a method in which a vent hole is formed in a retainer for accommodating an inflator and the vent hole is opened and closed by a control valve to finely control the deployment speed and internal pressure of the airbag (Japanese Patent Application No. See Hei 10-143781). [0006] [Problems to be Solved by the Invention] However, the one proposed in Japanese Patent Application No. 10-143781 has a piezoelectric element of the same shape bonded to a protector whose control valve is made of a strip-shaped metal plate, and the protector together with the piezoelectric element is energized. Since the vent hole is opened by bending the piezoelectric element, there is a problem that the expensive piezoelectric element becomes large and causes an increase in cost. [0007] The present invention has been made in view of the above circumstances, and an object of the present invention is to reduce the cost by downsizing the actuator of the control valve in an airbag device provided with a control valve capable of opening and closing a vent hole formed in a retainer. And. [0008] [Means for solving problems] In order to achieve the above object, according to the invention of claim 1, the inflator is housed inside the retainer to which the peripheral edge of the opening of the folded airbag is fixed, and the inflator is generated in the event of a vehicle collision. In an airbag device that deploys an airbag with gas to restrain an occupant and is provided with a control valve capable of opening and closing a vent hole formed in the retainer, the control valve is<u style="single">One end in the longitudinal direction is fixed to the retainer and said</u>Close the vent hole<u style="single">Strip-shaped</u>Valve body and this valve body<u style="single">Piezoelectric element that can drive</u>Consists of<u style="single">The valve body includes a hinge portion connected to the fixed end of the retainer, and a main body portion longer than the hinge portion, which is connected to the side opposite to the fixed end of the hinge portion and covers the vent hole. The piezoelectric element is adhered to one surface of the hinge portion on the side opposite to the vent hole, and the piezoelectric element in the energized state causes the piezoelectric element to be used.</u>Valve body<u style="single">The</u>Hinge part<u style="single">so</u>Bend<u style="single">hand</u>Open the vent hole<u style="single">It is possible, and a pair of flange portions extending along the longitudinal direction of the valve body are formed on both side edges of the main body in the width direction so as to project from one surface of the main body opposite to the vent hole. Ru</u>An airbag device characterized by the fact that it has been proposed<u style="single">Further, according to the invention described in claim 2, the inflator is housed inside the retainer to which the peripheral edge of the opening of the folded airbag is fixed, and the airbag is deployed by the gas generated by the inflator in the event of a vehicle collision. In an airbag device for restraining an occupant and provided with a control valve capable of opening and closing a vent hole formed in the retainer, the control valve has one end fixed to the retainer in the longitudinal direction and the vent is provided. The valve body is composed of a strip-shaped valve body that closes the hole and a piezoelectric element that can drive the valve body. The valve body has a hinge portion connected to a fixed end thereof to the retainer and the fixing of the hinge portion. It is provided with a main body portion longer than the hinge portion, which is connected to the side opposite to the end and covers the vent hole, and the piezoelectric element is adhered to one surface of the hinge portion on the side opposite to the vent hole to energize. The piezoelectric element in the state allows the valve body to be bent at the hinge portion to open a vent hole, and a pair of widthwise both edge portions of the main body portion extend along the longitudinal direction of the valve body. An airbag device has been proposed, wherein the bead portion is formed so as to project from one surface of the main body portion opposite to the vent hole.</u>To. [0009] According to the above configuration, when the airbag is deployed with the high-pressure gas generated by the inflator, the opening speed of the vent hole that allows the high-pressure gas to escape is controlled by the control valve, so that the deployment speed of the airbag and the binding force of the airbag are controlled. The size of the airbag, the contraction speed of the airbag, and the like can be arbitrarily set according to the state of the collision and the state of the occupant. Also<u style="single">The opening of the vent hole can be precisely and steplessly controlled by an extremely simple structure in which the piezoelectric element adhered to the hinge portion of the strip-shaped valve body covering the vent hole is energized to bend the hinge portion. Moreover, since the piezoelectric element is provided only in the hinge part of the valve body, not only can the amount of expensive piezoelectric element used be reduced to contribute to cost reduction, but also the piezoelectric element can be used.</u>Enlarge the slight movement of<u style="single">By transmitting to the valve body</u>The valve body can be operated greatly, and the actuator<u style="single">(Piezoelectric element) significantly</u>It is possible to reduce the cost by downsizing.<u style="single">Further, since the rigidity of the main body of the valve body is increased by the flanges on both side edges in the width direction, the main body can be brought into close contact with the retainer to reliably close the vent hole.</u>[0012] Further, according to the invention described in claim 3, claim 1<u style="single">Or 2 inventions</u>In addition to the above configuration, an airbag device is proposed in which the valve body of the control valve covers the vent hole from the outside of the retainer. [0013] According to the above configuration, since the valve body of the control valve covers the vent hole from the outside of the retainer that houses the inflator inside, even if the control valve is not sufficiently opened due to insufficient operation or non-operation of the actuator. It is possible to prevent the internal pressure of the airbag from being excessively increased by forcibly opening the control valve due to the increase in the internal pressure of the retainer. [0014] BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described based on the examples of the present invention shown in the accompanying drawings. [0015] 1 to 15 show an embodiment of the present invention, FIG. 1 is a perspective view of the front part of the passenger compartment of an automobile, FIG. 2 is an enlarged sectional view taken along line 2-2 of FIG. 1, and FIG. 3 is FIG. 3-3 cross-sectional view, Fig. 4 is an enlarged cross-sectional view of line 4-4 in Fig. 2, Fig. 5 is a cross-sectional view of line 5-5 in Fig. 4, and Fig. 6 is an exploded perspective view of the driver airbag device. 7 is an enlarged cross-sectional view of line 7-7 in Fig. 2, Fig. 8 is a cross-sectional view of line 8-8 in Fig. 7, Fig. 9 is an enlarged cross-sectional view of line 9-9 in Fig. 8, and Fig. 10 is a magnified view of line 10-10 in Fig. 9. FIG. 11 is an exploded perspective view of the passenger airbag device, FIG. 12 is a block diagram showing a control system for the opening degree of the vent hole, and FIG. 13 is a view showing an example of the opening pattern of the vent hole. 14 is a diagram showing a change in the opening pattern of the vent hole depending on the state of the occupant, and FIG. 15 is a diagram showing a change in the opening pattern of the vent hole depending on the vehicle speed. [0016] As shown in FIG. 1, the driver airbag device Rd is provided in the center of the steering wheel 2 arranged in front of the driver's seat 1, and the dashboard 4 arranged in front of the passenger seat 3 is provided. An airbag device Rp for the passenger seat is installed at the top. [0017] Next, the structure of the driver airbag device Rd will be described with reference to FIGS. 2 to 6. [0018] The steering wheel 2 includes a steering boss 13 that is fitted to the rear end of the steering shaft 11 so as not to rotate relative to each other and is fixed by a nut 12, an annular wheel rim 14 arranged so as to surround the steering boss 13, and the above. It is equipped with a front cover 15 fixed to the steering boss 13, a rear cover 16 coupled to the front cover 15, and a plurality of spokes 17 ... for connecting the front cover 15 to the wheel rim 14. The airbag module 18 is housed in the space partitioned by the cover 15 and the rear cover 16. [0019] The airbag module 18 includes a retainer 19 for supporting it inside the rear cover 16, an inflator 20 that generates high-pressure gas, and an airbag 21 that is inflated by the high-pressure gas generated by the inflator 20. A mounting flange formed by superimposing the outer peripheral portion of the square plate-shaped retainer 19, the outer peripheral portion of the bracket 22 that supports the inflator 20 in the center, and the outer peripheral portion of the opening of the airbag 21 and integrally formed on the inner circumference of the rear cover 16. It is fastened together with multiple bolts 23 ... on 16a. The gas outlet 20a ... of the inflator 20 is open to the internal space of the airbag 21, and the internal space of the airbag 21 is a bracket through the four through holes 22a ... formed in the bracket 22. It communicates with the space between 22 and the retainer 19. [0020] A rectangular vent hole 29 is formed in the retainer 19 facing the bracket 22. The control valve 30 that controls the opening degree of the vent hole 29 includes a valve body 32 that is formed in a strip shape and has one end in the longitudinal direction fixed to the outer surface of the retainer 19 by a bolt 31 .... The valve body 32 is composed of a main body portion 32a that covers the vent hole 29 and a hinge portion 32b provided at a position close to the bolt 31 ... of the main body portion 32a. To increase the rigidity of the main body 32a of the valve body 32<u style="single">In its width direction</u>Both edges are bent<u style="single">, A pair extending in the longitudinal direction of the valve body 32, respectively</u>Flange 32c and 32c are formed. Further, in order to bend the valve body 32 at the hinge portion 32b, a quadrangular piezoelectric element 33 as an actuator is adhered to the back surface of the hinge portion 32b. [0021] [0021] As shown in FIG. 12, the airbag deployment control device 34 includes an acceleration detecting means 35a for detecting the acceleration at the time of a vehicle collision and a occupant state detecting means for detecting the occupant state such as the weight, physique, and sitting posture of the occupant. The 35b and the vehicle speed detecting means 35c for detecting the vehicle speed are connected. The occupant state detecting means 35b is provided on a seat cushion to identify an adult and a child by detecting the weight of the occupant, or an infrared ray to identify an adult and a child by detecting the sitting height of the occupant. To. [0022] The airbag deployment control device 34 ignites the inflator 20 when an acceleration exceeding a predetermined value is detected at the time of a vehicle collision, and the airbag 21 inflated by the gas generated by the inflator 20 is formed in an H shape on the rear cover 16. Break the thin tier line 16b (see Fig. 6) and deploy it in the passenger compartment. At this time, the airbag deployment control device 34 controls the energization of the control valve 30 to the piezoelectric element 33 based on the signal from the occupant state detecting means 35b or the vehicle speed detecting means 35c, and changes the opening degree of the vent hole 29. [0023] That is, when the piezoelectric element 33 is not energized, the hinge portion 32b of the valve body 32 of the control valve 30 extends linearly as shown by the solid line in FIG. 5, and the main body portion 32a connected to the hinge portion 32b is a vent hole 29. Is blocked. When the piezoelectric element 33 is energized from this state, the piezoelectric element 33 contracts according to the amount of energization as shown by the chain line in FIG. 5, so that the hinge portion 32b of the valve body 32 is curved and the main body portion 32a opens the vent hole 29. Open. [0024] In this way, the opening degree of the vent hole 29 can be precisely and steplessly controlled by an extremely simple structure in which the piezoelectric element 33 provided in the valve body 32 covering the vent hole 29 is energized and curved. .. Moreover, since the piezoelectric element 33 is provided only on the hinge portion 32b of the valve body 32 of the control valve 30, the piezoelectric element 33 is more expensive than the case where the piezoelectric element 33 is provided on the entire surface of the main body portion 32a of the valve body 32. Not only can the amount of the piezoelectric element 33 be reduced to contribute to cost reduction, but also the slight movement of the piezoelectric element 33 can be expanded and transmitted to the valve body 32. Further, since the rigidity of the main body 32a of the valve body 32 is increased by the flanges 32c and 32c, the main body 32a can be brought into close contact with the retainer 19 to securely close the vent hole 29. [0025] Further, since the valve body 32 covers the vent hole 29 from the outer surface of the retainer 19 (the surface opposite to the surface facing the inflator 20), the piezoelectric element 33 does not operate sufficiently or fails when the inflator 20 generates high pressure gas. Even if the valve body 32 is not sufficiently opened by the operation, the valve body 32 can be forcibly opened to the outside by increasing the gas pressure inside the retainer 19, which causes the internal pressure of the airbag 21 to be excessively increased. Can be prevented. [0026] A plurality of opening patterns of the vent hole 29, that is, a change in the opening degree of the vent hole 29 with the passage of time is stored in advance as a map, and the airbag deployment control device 34 is predetermined from the plurality of opening patterns. The control valve 30 is controlled by selecting the opening pattern of. The specific content of the opening control of the control valve 30 will be described in detail later. [0027] Next, the structure of the passenger airbag device Rp will be described with reference to FIGS. 7 to 11. [0028] The retainer 43 of the airbag module 42 is fixed to the support portion 41a ... Extending downward from the lid 41 fixed to the opening 4a formed on the upper surface of the dashboard 4. The retainer 43 is composed of an upper retainer 45 and a lower retainer 46 fixed by a plurality of bolts 44 ..., and the upper retainer 44 is a support portion 41a ... of the lid 41 with a plurality of bolts 47 ... Is fixed to. The peripheral edge of the opening of the airbag 48 is sandwiched between the joints of the upper retainer 45 and the lower retainer 46 and fastened together with the bolts 47 ... The lid 41 is formed with a thin tier line 41b that breaks when the airbag 48 expands. A cylindrical inflator 50 is supported at the bottom of the lower retainer 46 via a pair of mounting brackets 49,49. [0029] The control valve 30 that opens and closes the rectangular vent hole 29 formed at the bottom of the lower retainer 46 has substantially the same structure as that of the driver's seat airbag device Rd, and the hinge portion 32b of the valve body 32. The hinge portion 32b is bent by energizing the piezoelectric element 33 provided in the above, and the main body portion 32a is separated from the vent hole 29. However, the valve body 32 of the control valve 30 of the driver airbag device Rd gives rigidity to the main body 32a by the flanges 32c and 32c, whereas the valve of the control valve 30 of the passenger airbag device Rp. The body 32 is different in that the bead 32d and 32d give rigidity to the main body 32a, and other structures and actions are the same. [0030] The energization of the inflator 50 and the control valve 30 is controlled by the airbag deployment control device 34 to which signals from the acceleration detecting means 35a, the occupant state detecting means 35b, and the vehicle speed detecting means 35c are input. That is, when the acceleration detecting means 35a detects an acceleration equal to or higher than a predetermined value at the time of a vehicle collision, the inflator 50 is ignited by a command from the airbag deployment control device 34 to generate high pressure gas, and the airbag 48 expands at that pressure. Breaks the tier line 41b of the lid 41 and deploys it in the passenger compartment. At this time, the opening degree of the control valve 30 is controlled by the signals from the occupant state detecting means 35b and the vehicle speed detecting means 35c. [0031] Next, the contents of the opening / closing control of the vent hole 29 of the driver airbag device Rd and the passenger airbag device Rp will be specifically described with reference to FIGS. 13 to 15. [0032] The horizontal axis of FIG. 13A shows the time since the airbags 21,48 completed the deployment, and the vertical axis shows the magnitude of the load received from the airbags 21,48 by the occupant. The horizontal axis of FIG. 13 (B) also shows the time since the airbags 21 and 48 completed deployment, and the vertical axis shows the opening degree of the vent hole 29 (with the fully open state as 100%). There is. Here, the broken line corresponds to the conventional one in which the vent holes of a certain area are provided in the airbags 21 and 48, and the solid line corresponds to the present embodiment in which the opening degree of the vent hole 29 formed in the retainer 19 is controlled by the control valve 30. To do. [0033] As is clear from the figure, in this embodiment, the opening degree of the vent hole 29 is kept small in the region a at time t0 to t1 to make it difficult for the gas to be discharged from the airbags 21, 48, thereby causing the inertia of the collision. It increases the initial restraining load when the forward occupant begins to push the airbags 21,48. By increasing the opening of the vent hole 29 in the region b of the following time t1 to t2 and keeping the opening of the vent hole 29 at a large value in the region c of the time t2 to t3, the occupant can start from the airbags 21,48. The maximum value of the restraint load received is reduced to softly restrain the occupant. By reducing the opening of the vent hole 29 in the region d of the following time t3 to t4 and keeping the opening of the vent hole 29 small in the region e of the following time t4 to t4 to make it difficult for gas to be discharged from the airbags 21 and 48. , The airbags 21, 48 are prevented from contracting early, and the impact of the occupant's secondary collision with the steering wheel 2 and dashboard 4 is sufficiently mitigated. [0034] In this way, since the opening degree of the vent hole 29 is controlled according to the preset opening degree pattern, the characteristics of the load received by the occupants from the airbags 21 and 48 can be arbitrarily controlled to approach the ideal characteristics. .. [0035] The opening pattern of the vent hole 29 is changed according to the detection result of the occupant state detecting means 35b. That is, as shown in FIG. 14, when the weight of the occupant is small, the fully open opening degree of the vent hole 29 in the region c is set to 100%, but when the weight of the occupant is large, the weight increases. The full opening opening is gradually reduced from 100% to, for example, 70%. The reason is that if the fully open opening of the vent hole 29 is too large when the occupant's weight is heavy, the amount of gas discharged from the vent hole 29 becomes too large due to the load that the occupant compresses the airbags 21, 48, and the air. This is because the bags 21, 48 may not be able to be maintained in the inflated state. [0036] The opening pattern of the vent hole 29 is changed according to the detection result of the vehicle speed detecting means 35c. That is, as shown in FIG. 15, when the vehicle speed at the time of a collision is low, the required binding force is also small, so that the fully open opening degree of the vent hole 29 is set large and the fully open opening degree is maintained until the end. As a result, the maximum value of the restraint load that the occupant receives from the airbags 21, 48 can be reduced, and the occupant can be restrained more softly. [0037] Although the examples of the present invention have been described in detail above, the present invention can make various design changes without departing from the gist thereof. [0038] For example<u style="single">、</u>Shape of vent hole 29, shape of valve body 32 of control valve 30, piezoelectric element 3<u style="single">3</u>The shape of is not limited to the examples and can be changed as appropriate.<u style="single">。</u>[0039] [Effect of the invention] Claim 1 as described above<u style="single">, 2 respectively</u>Described<u style="single">each</u>According to the invention, when the airbag is deployed with the high-pressure gas generated by the inflator, the opening of the vent hole through which the high-pressure gas escapes is controlled by the control valve to control the deployment speed of the airbag and the binding force of the airbag. The size, the contraction speed of the airbag, and the like can be arbitrarily set according to the state of the collision and the state of the occupants. Also<u style="single">The opening of the vent hole can be precisely and steplessly controlled by an extremely simple structure in which the piezoelectric element adhered to the hinge portion of the strip-shaped valve body covering the vent hole is energized to bend the hinge portion. Moreover, since the piezoelectric element is provided only in the hinge part of the valve body, not only can the amount of expensive piezoelectric element used be reduced to contribute to cost reduction, but also the piezoelectric element can be used.</u>Enlarge the slight movement of<u style="single">By transmitting to the valve body</u>The valve body can be operated greatly, and the actuator<u style="single">(Piezoelectric element) significantly</u>It is possible to reduce the cost by downsizing.<u style="single">Further, since the rigidity of the main body of the valve body is increased by the flanges on both side edges in the width direction, the main body can be brought into close contact with the retainer to reliably close the vent hole.</u>[0041] Further, according to the invention of claim 3, since the valve body of the control valve covers the vent hole from the outside of the retainer that houses the inflator inside, the control valve is sufficiently operated due to insufficient operation or non-operation of the actuator. Even when the airbag is not opened, the control valve can be forcibly opened by increasing the internal pressure of the retainer to prevent the internal pressure of the airbag from increasing excessively. [Simple explanation of drawings] FIG. 1 is a perspective view of the front part of the passenger compartment of an automobile. FIG. 2 is an enlarged cross-sectional view taken along line 2-2 of FIG. FIG. 3 is a sectional view taken along line 3-3 of FIG. FIG. 4 is an enlarged arrow view of line 4-4 in FIG. 5 is a cross-sectional view taken along line 5-5 of FIG. FIG. 6 is an exploded perspective view of an airbag device for the driver's seat. FIG. 7 is an enlarged cross-sectional view taken along line 7-7 of FIG. FIG. 8 is a sectional view taken along line 8-8 of FIG. FIG. 9 is an enlarged arrow view of line 9-9 in FIG. 10 is a cross-sectional view taken along line 10-10 of FIG. FIG. 11 is an exploded perspective view of an airbag device for a passenger seat. FIG. 12 is a block diagram showing a control system for opening a vent hole. FIG. 13 is a diagram showing an example of an opening pattern of a vent hole. FIG. 14 is a diagram showing a change in the opening pattern of a vent hole depending on the state of an occupant. FIG. 15 is a diagram showing a change in the opening pattern of a vent hole depending on the vehicle speed. [Explanation of symbols] 19 Retainer 20 Inflator 21 airbag 29 Vent hole 30 Control valve 32 valve body<u style="single">32a</u><u style="single">Body</u>32b hinge part<u style="single">32c</u><u style="single">Flange part</u><u style="single">32d</u><u style="single">Bead part</u>33 Piezoelectric element<u style="single">Child</u>43 retainer 48 airbag 50 inflator