JP6288203B1 - Knee airbag device - Google Patents

Abstract

To reduce the size of a case of a knee airbag device and to effectively relieve an impact load applied to a passenger's knee from the case while ensuring sufficient resistance to the internal pressure generated when the bag is inflated and deployed. . A case 48 having a peripheral wall 52 disposed in an instrument panel 2, a bag 70 housed in the case 48 so as to be surrounded by the peripheral wall 52, and the bag 70 being inflated to expand the peripheral wall. In the knee airbag device 1 provided with an inflating means 72 that is deployed to one side in the axial direction X of the 52, a plurality of fragile portions 54 are provided in the circumferential wall 52 at intervals in the circumferential direction, and the outer circumferential surface of the circumferential wall 52 Further, a reinforcing member 58 that covers the plurality of fragile portions 54 from the outside is provided so as to extend in the circumferential direction Y. [Selection] Figure 3

Description

  The present invention relates to a knee airbag device for protecting an occupant's knee, and belongs to the vehicle occupant protection technical field.

  In recent years, various airbag devices for protecting an occupant in the event of a vehicle collision have been put into practical use. As one type, a knee airbag that absorbs the kinetic energy of the knee of the front seat occupant and reduces the impact on the knee. The device is known. The knee airbag device is disposed, for example, at a position facing the front side of the body of the knee of the front seat occupant via the instrument panel.

  The knee airbag device includes an inflator that generates gas, a bag that is inflated and deployed by the gas generated by the inflator, and a case that houses the inflator and the bag, as in a general airbag device.

  By the way, the case of the knee airbag device is constituted by a rigid body having such a rigidity that it can withstand the internal pressure when the bag is inflated. Therefore, when the kinetic energy of the occupant's knee cannot be sufficiently absorbed by the inflated and deployed bag, the occupant's knee moved to the front side of the vehicle body with respect to the vehicle body collides with the rigid case via the instrument panel. In this case, there is a problem that the impact load that the occupant's knee receives is likely to increase.

  In order to solve such a problem, Patent Document 1 discloses a technique in which a plurality of notches are provided in a corner portion of a case of a knee airbag device with reference to FIG. According to the technology, when the occupant's knee collides with the case of the knee airbag device, the case is easily deformed, so that the impact load applied to the occupant's knee can be reduced.

  Patent Document 2 discloses a technique in which a case of a knee airbag device is constituted by a pair of case members connected in the longitudinal direction of the vehicle body. Among the pair of case members, the case member on the rear side of the vehicle body is provided with a plurality of slots extending in the longitudinal direction of the vehicle body, and the pair of case members are fixed to each other using rivets inserted into these slots. . According to the technique of Patent Document 2, the case member on the rear side of the vehicle body that collides with the occupant's knee slides toward the front side of the vehicle body relative to the case member on the front side of the vehicle body. It can be mitigated.

JP-A-9-123863 JP 2004-352118 A

  However, if the case of the knee airbag device is provided with a notch or a slot as in the techniques of Patent Documents 1 and 2, the rigidity of the case is reduced, so that the case is easily deformed by the internal pressure generated when the bag is inflated and deployed. There is a possibility that the bag cannot be normally inflated and deployed.

  Further, in the technique of Patent Document 2, since the case member needs to be configured to be slidable in the longitudinal direction of the vehicle body, the entire case is enlarged in the longitudinal direction of the vehicle body. As a result, peripheral parts such as a drive unit of the electric power steering mechanism There is also a problem that the case easily interferes.

  Therefore, the present invention aims to reduce the size of the case of the knee airbag device and to effectively apply the impact load applied from the case to the occupant's knee while ensuring good resistance to the internal pressure generated when the bag is inflated and deployed. It is an issue to relax.

  In order to solve the above problems, a knee airbag device according to the present invention is configured as follows.

The invention according to claim 1 of the present application is
A case having a peripheral wall disposed in the instrument panel; a bag housed in the case so as to be surrounded by the peripheral wall; and inflating means for inflating the bag and deploying the bag toward one side in the axial direction of the peripheral wall. A knee airbag device comprising:
The peripheral wall is provided with a plurality of fragile portions at intervals in the circumferential direction,
A reinforcing member that covers the plurality of fragile portions from the outside is provided on the outer peripheral surface of the peripheral wall so as to extend in the circumferential direction.

The invention according to claim 2 of the present application is the invention according to claim 1,
The peripheral wall is composed of a plurality of wall surfaces connected to each other through a corner portion,
The fragile portion is provided on at least one predetermined wall surface portion of the plurality of wall surface portions.

The invention according to claim 3 of the present application is the invention according to claim 2,
The fragile portion is further provided in a corner portion adjacent to one side or both sides in the circumferential direction of the predetermined wall surface portion in the peripheral wall.

The invention according to claim 4 of the present application is the invention according to claim 2 or claim 3, wherein
The fragile portion is provided on a plurality of the wall surfaces adjacent to each other on the peripheral wall.

The invention according to claim 5 of the present application is the invention according to any one of claims 1 to 4,
The reinforcing member is provided over the entire circumference of the peripheral wall.

The invention according to claim 6 of the present application is the invention according to any one of claims 3 to 5,
The fragile portion is a slit extending in the axial direction of the peripheral wall.

The invention according to claim 7 of the present application is the invention according to claim 6,
The slit has a length larger than the width of the reinforcing member in the axial direction of the peripheral wall.

The invention according to claim 8 of the present application is the invention according to any one of claims 1 to 7,
The case includes a case main body having the peripheral wall, and a lid member that closes an opening formed at one axial end of the peripheral wall.
A plurality of engaging portions that can be engaged with the lid member are provided on the peripheral wall at intervals in the circumferential direction.
The reinforcing member is provided between the engagement portion and the opening in the axial direction of the peripheral wall,
The lid member includes a covering portion that covers the reinforcing member from the outside.

The invention according to claim 9 of the present application is the invention according to any one of claims 1 to 8,
In the instrument panel, a drive unit of a power steering mechanism is disposed,
The case is disposed adjacent to the vehicle body rear side of the drive unit.

  Here, “adjacent to the rear side of the vehicle body” includes “adjacent to the rear upper side of the vehicle body” and “adjacent to the lower rear side of the vehicle body”.

  According to the knee airbag device according to the invention described in claim 1, when the knee of the occupant who has moved relative to the vehicle body relative to the vehicle body collides with the case of the knee airbag device via the instrument panel, Since the peripheral wall of the case is provided with a plurality of fragile portions, deformation to the inside of the case is promoted. Thus, the reinforcing member provided so as to extend in the circumferential direction so as to cover the plurality of fragile portions from the outside with respect to the impact applied to the peripheral wall from the outside does not substantially perform the reinforcing function for the peripheral wall. Moreover, since the gap between the outer peripheral surface of the peripheral wall and the reinforcing member is enlarged along with the deformation of the peripheral wall, the tension of the reinforcing member is lowered, and the reinforcing function by the reinforcing member is further limited. The deformation of is further promoted. Therefore, the impact applied to the passenger's knee from the case can be effectively reduced.

  Further, when the bag housed in the case is inflated by the inflating means, the deformation of the peripheral wall to the outside of the case is effectively suppressed by the reinforcing member stretched outside the portion where the fragile portion is provided. Thereby, the fall of the yield strength of the surrounding wall with respect to the internal pressure at the time of bag expansion | swelling can be suppressed. Therefore, when the bag is inflated and deployed, the reaction force from the peripheral wall of the case to the bag can be favorably obtained, so that the bag can be easily deployed in a predetermined manner toward one side in the axial direction of the peripheral wall. Therefore, the passenger's knee can be effectively protected by the normally deployed bag.

  Furthermore, since the fragile portion for promoting the deformation of the peripheral wall due to the impact from the outside as described above and the reinforcing member for suppressing the deformation of the peripheral wall due to the internal pressure are provided so as to overlap in the radial direction of the peripheral wall, There is no need to expand the layout space of the reinforcing members in the axial direction. Therefore, when the axial direction one end side of the peripheral wall is directed toward the vehicle rear side so that the bag can be deployed from the case disposed in the instrument panel to the vehicle rear side, the peripheral wall and the reinforcing member are arranged in the vehicle longitudinal direction. It is easy to avoid interference with peripheral parts in the instrument panel.

  According to the second aspect of the present invention, the fragile portion is provided on at least one predetermined wall surface portion that is likely to hit the occupant's knee among the plurality of wall surface portions constituting the peripheral wall of the case, so that the occupant is provided on the predetermined wall surface portion. When the knees collide, the deformation of the predetermined wall surface inward of the case can be effectively promoted, whereby the impact applied to the occupant's knee from the case can be effectively mitigated.

  According to the invention described in claim 3, the fragile portion is provided on the predetermined wall surface portion of the peripheral wall of the case and the corner portion adjacent to the one or both sides in the circumferential direction, thereby covering the fragile portion from the outside. The predetermined wall surface where the occupant's knee collided and the peripheral wall portion around the occupant's knee can be effectively deformed toward the inside of the case, thereby effectively reducing the impact applied to the occupant's knee. It can be mitigated more effectively.

  According to the invention described in claim 4, the weak wall portions are provided in the plurality of wall surfaces adjacent to each other in the peripheral wall of the case, so that not only the wall surface portion where the occupant's knee collided but also the wall surface portion adjacent thereto In addition, while effectively reducing the tension of the reinforcing member, it is possible to effectively promote the deformation of the peripheral wall inward of the case, thereby more effectively mitigating the impact applied to the occupant's knee Can do.

  According to the fifth aspect of the present invention, the reinforcing member is provided over the entire circumference of the peripheral wall of the case, so that when the bag stored in the case is inflated by the inflating means, the case outwards. The deformation of the peripheral wall can be suppressed by the reinforcing member over the entire periphery, and thereby the proof stress of the peripheral wall against the internal pressure during the bag inflation can be effectively improved.

  According to the sixth aspect of the present invention, the fragile portion is configured by the slit extending in the axial direction of the peripheral wall of the case, so that the effect of promoting deformation of the peripheral wall portion in which the slit is formed to the inside of the case, and the slit The effect of suppressing deformation of the peripheral wall to the outside of the case by being covered from the outside by the reinforcing member can be realized in a well-balanced manner.

  If the invention according to claim 7 is applied to the invention according to claim 6, since the slit is formed longer than the width of the reinforcing member in the axial direction of the peripheral wall, the occupant's knee collided with the case Sometimes, the peripheral wall portion around the slit can be effectively deformed inward of the case.

  According to the eighth aspect of the present invention, the opening formed at one axial end of the peripheral wall of the case body is closed by the cover member, and the cover member is engaged with the plurality of engaging portions provided on the peripheral wall. In this case, the reinforcing member is provided closer to the opening side than the engaging portion in the axial direction of the peripheral wall, so that the vicinity of the opening portion that is more easily deformed on the peripheral wall of the case body is effectively provided by the reinforcing member. Can be reinforced. In addition, since the reinforcing member is covered from the outside by the cover portion of the lid member, the reinforcing member can be reliably prevented from dropping off or being damaged, and thereby the peripheral wall can be reliably reinforced by the reinforcing member.

  According to the ninth aspect of the present invention, the case configured in a compact manner as described above is disposed in the instrument panel using the space between the drive unit of the power steering mechanism and the instrument panel. can do. In addition, when the occupant's knee moves relative to the vehicle body relative to the vehicle body, the peripheral wall of the case interposed between the drive unit and the occupant's knee is effectively deformed as described above, thereby driving the vehicle. The impact applied to the passenger's knee from the unit can be effectively absorbed.

It is the rear view which looked at the knee airbag device concerning a 1st embodiment of the present invention, and its peripheral part from the vehicle body back side rather than an instrument panel. FIG. 2 is a cross-sectional view taken along the line AA of FIG. It is a disassembled perspective view which shows the case main body and cover member in the case of the knee airbag apparatus. It is a perspective view which shows the same case in an assembly state. It is sectional drawing similar to FIG. 2 which looked at the knee airbag apparatus which concerns on 2nd Embodiment of this invention, and its peripheral part from the vehicle body side side.

  Hereinafter, details of a side body structure of a vehicle according to the present invention will be described for each embodiment with reference to the accompanying drawings. In the following description, terms indicating directions such as “front”, “rear”, “left”, “right” and the like indicate the traveling direction of the vehicle when traveling forward unless otherwise specified. Each direction of the vehicle body in the case of “front” shall be indicated.

[First Embodiment]
As shown in the rear view of FIG. 1 and the cross-sectional view of FIG. 2, the knee airbag device 1 according to the first embodiment of the present invention protects the knee N1 of the occupant seated on the seat 8 of the driver's seat. The vehicle seat is disposed on the front side of the vehicle seat 8.

  In the present embodiment, the present invention will be described by taking a left-hand drive vehicle as an example, but the present invention can be equally applied to a right-hand drive vehicle. Moreover, although this embodiment demonstrates the knee airbag apparatus for driver's seats, this invention does not prevent applying to the knee airbag apparatus for seats other than a driver's seat.

[Peripheral structure]
The peripheral structure of the knee airbag device 1 will be described with reference to FIGS. 1 and 2.

  An instrument panel 2 is arranged on the front side of the vehicle body of the seat 8 of the driver's seat, and the space on the front side of the vehicle body across the instrument panel 2 is the space inside the instrument panel (hereinafter, “instrument panel space”). S1, the space on the rear side of the vehicle body is the vehicle interior space S2. The instrument panel 2 includes a lower panel 2b facing the vehicle body front side of the occupant's knee N1, and an upper panel 2a disposed on the vehicle body upper side of the lower panel 2b.

  The instrument panel 2 includes a meter unit 3, a meter cover 4 that covers the meter unit 3 from the vehicle interior space S <b> 2 side, an air conditioning unit (not shown), an audio unit (not shown), and an instrument panel member (hereinafter “ 6) and the like, which are assembled as an instrument panel module in a unitized state.

  The instrument panel member 6 is a pipe-like member extending in the vehicle body width direction in the instrument panel inner space S1, and is spanned between left and right hinge pillars (not shown).

  A steering wheel 10 that is operated by an occupant seated in a driver's seat is disposed on the vehicle body rear side of the instrument panel 2. The steering wheel 10 is supported by the instrument panel member 6 via a steering support mechanism 12.

  The steering support mechanism 12 includes a steering shaft 14 provided through the instrument panel 2 so as to straddle the instrument panel space S1 and the vehicle interior space S2, and a bearing (not shown) outside the steering shaft 14. ) Through the steering column 16.

  The steering shaft 14 is disposed so as to be inclined toward the vehicle body upper side toward the vehicle body rear side. The steering shaft 14 is disposed so as to pass through the instrument panel member 6 on the lower side of the vehicle body in the instrument panel inner space S1. A steering wheel 10 is attached to an end portion (rear end portion) of the steering shaft 14 on the vehicle interior space S2 side. An intermediate shaft 24 is connected to an end portion (front end portion) of the steering shaft 14 on the instrument panel inner space S <b> 1 side via a universal joint 22.

  The intermediate shaft 24 is disposed so as to be inclined toward the vehicle body lower side toward the vehicle body front side, and the lower end portion of the intermediate shaft 24 is connected to the left and right front wheels via, for example, a rack and pinion mechanism. .

  The steering column 16 includes an upper column 17 fitted to a relatively upper portion of the steering shaft 14 and a lower column 18 fitted to a relatively lower portion of the steering shaft 14. The upper column 17 has a larger diameter than the lower column 18. The lower end portion of the upper column 17 is fitted to the outside of the upper end portion of the lower column 18 so as to be relatively movable in the axial direction.

  A column cover 20 is fixed to the upper column 17. A portion from the rear end portion to the center portion of the upper column 17 is covered with the column cover 20, and the front end portion of the upper column 17 is exposed to the front side of the vehicle body from the front end portion of the column cover 20. The upper column 17 and the column cover 20 are provided through the instrument panel 2. The column cover 20 is inserted through an opening 2c (see FIG. 1) provided at the boundary between the upper panel 2a and the lower panel 2b in the instrument panel 2.

  A drive unit 30 of an electric power steering mechanism is attached to the lower column 18. The drive unit 30 includes an electric motor (not shown) as a drive source, a worm (not shown) that rotates integrally with its output shaft, and a worm wheel (not shown) that meshes with the worm. The shaft C1 of the electric motor and the worm is disposed along the vehicle body width direction on the vehicle body lower side of the steering shaft 14. The worm wheel is provided on the steering shaft 14. The rotation of the electric motor is decelerated between the worm and the worm wheel and transmitted to the steering shaft 14.

  The drive unit 30 includes a motor case 32 that houses an electric motor and a worm, and a worm wheel case 34 that houses a worm wheel. The motor case 32 and the worm wheel case 34 are integrally provided, for example. The worm wheel case 34 is fixed to the lower column 18.

  The steering column 16 is supported by the instrument panel member 6 via first, second and third brackets 25, 26 and 27. The first bracket 25 is fixed to the instrument panel member 6 by welding, for example. The second bracket 26 is disposed on the front side of the vehicle body with respect to the axis of the instrument panel member 6 and is fixed to the first bracket 25 by bolts, for example. The third bracket 27 is disposed on the rear side of the vehicle body with respect to the axial center of the instrument panel member 6, and is fixed to the first bracket 25 by, for example, a bolt.

  The lower column 18 is supported by the second bracket 26 via a tilt shaft 36 extending in the vehicle body width direction so as to be rotatable around the tilt shaft 36. The upper column 17 is supported by the third bracket 27 via a spring 21 that applies a biasing force toward the rear end side in the axial direction. Although the relative movement of the upper column 17 with respect to the third bracket 27 is restricted by a lock mechanism (not shown), the relative movement of the upper column 17 with respect to the third bracket 27 is achieved by releasing the lock by the lock mechanism. Is possible. An operation lever 44 for releasing the lock by the lock mechanism is supported on the third bracket 27 via a support shaft 42 extending in the vehicle body width direction.

  The operation lever 44 is rotatably fitted to the support shaft 42 at one end side, extends from the fitting portion to the vehicle body lower side, and a lower end portion of the first lever portion 44a via a bending portion. And a second lever portion 44b extending from the curved portion toward the rear end side in the axial direction of the steering column 16. The second lever portion 44b is housed in a recess 20a provided on the lower surface of the column cover 20 in the vehicle body. The distal end portion of the second lever portion 44b is disposed in the vehicle interior space S2. The occupant can rotate the operation lever 44 around the support shaft 42 by grasping the tip end portion of the second lever portion 44 b and moving it up and down, whereby the occupant of the upper column 17 relative to the third bracket 27 can be rotated. Switching between the locked state and the unlocked state can be performed.

  In a state where the upper column 17 is unlocked, the steering column 16 can rotate about the tilt shaft 36. With the steering column 16 supported by the instrument panel member 6 in such a manner, a tilt mechanism 40 that changes the tilt angles of the steering column 16 and the steering shaft 14 is configured. By adjusting the tilt angle of the steering shaft 14 by the tilt mechanism 40, the vertical position of the steering wheel 10 in the vehicle body can be adjusted.

  As described above, the upper column 17 of the steering column 16 and the column cover 20 fixed thereto are provided so as to be movable relative to the lower column 18 in the axial direction. Therefore, when a passenger in the driver's seat moves relative to the front of the vehicle body and collides with the steering wheel 10 at the time of a vehicle collision or the like, the steering wheel 10 moves into the lower column 18 together with the upper column 17 and the column cover 20. On the other hand, relative movement to the front end side in the axial direction (hereinafter referred to as “collapse movement”) is possible. Thereby, it is possible to mitigate the impact applied to the occupant due to the collision with the steering wheel 10.

[Knee airbag device]
Hereinafter, the configuration of the knee airbag device 1 will be described.

  As shown in FIG. 2, the knee airbag device 1 is housed in a case 48 disposed adjacent to the vehicle body rear lower side of the drive unit 30 of the electric power steering mechanism in the instrument panel inner space S <b> 1. A bag 70 and an inflator 72 as inflating means for inflating the bag 70 are provided.

  The case 48 is attached to the motor case 32 of the drive unit 30 via the bracket 28, for example. The case 48 is disposed on the rear side of the vehicle body so as to face the vehicle interior space S2. The bag 70 is stored in the case 48 in a folded state, and is expanded from the case 48 to the vehicle interior space S2 when inflated by supplying gas from the inflator 72.

  As shown in FIG. 3, the case 48 includes a case main body 50 and a lid member 60. The case body 50 is disposed in the instrument panel inner space S1, and the lid member 60 is disposed along the instrument panel 2 (see FIG. 2). The case body 50 and the lid member 60 are made of resin, for example. More specifically, the lid member 60 is made of the same resin as that of the instrument panel 2, for example. The lid member 60 is made of a softer resin than the case body 50.

  The case body 50 includes a peripheral wall 52 having an opening 55 at one end in the axial direction X, and a bottom wall 51 that closes the other end of the peripheral wall 52 in the axial direction X.

  The peripheral wall 52 is disposed in the instrument panel space S1 so that the axial direction X is along the direction inclined toward the vehicle body lower side toward the vehicle body rear side (see FIG. 2). The peripheral wall 52 is composed of, for example, four wall surface portions 52a, 52b, 52c, and 52d that are connected via a corner portion in the circumferential direction Y, and is formed into a square cylindrical portion as a whole. Specifically, the four wall surface portions 52a, 52b, 52c, 52d of the peripheral wall 52 are a rear wall surface portion 52a (see FIG. 2) having an outer surface facing the rear upper side of the vehicle body, an inner surface facing the rear wall surface portion 52a, and the front of the vehicle body. A front wall surface portion 52b having an outer surface facing the lower side, and a pair of side wall surface portions 52c and 52d having an outer surface facing the vehicle body side and an inner surface facing each other.

  The rear wall surface portion 52a, the front wall surface portion 52b, and the pair of side wall surface portions 52c and 52d have, for example, a rectangular shape having a short side extending in the axial direction X and a long side extending in a direction perpendicular to the axial direction X. . The rear wall surface portion 52a, the front wall surface portion 52b, and the pair of side wall surface portions 52c, 52d have substantially the same short side length, and the rear wall surface portion 52a and the front wall surface portion 52b have the long sides defined by the pair of side wall surface portions 52c. , 52d is longer than the long side.

  A plurality of engaging portions 53 for engaging the lid member 60 are provided on the rear wall surface portion 52a at intervals in the long side direction (circumferential direction Y). Each engaging portion 53 is formed in a hook shape protruding outward from the outer surface of the rear wall surface portion 52a. Each engagement portion 53 is formed so as to extend in an L shape toward the side opposite to the opening 55 as viewed from the side wall surface portions 52c and 52d (the vehicle body side). In the axial direction X, the engaging portion 53 is provided on the side opposite to the opening 55 from the central portion of the rear wall surface portion 52a, but may be provided in the central portion of the rear wall surface portion 52a. Although not shown, a plurality of engaging portions 53 are similarly provided on the outer surface of the front wall surface portion 52b.

  The rear wall surface 52a is provided with a plurality of slits 54 at intervals in the long side direction (circumferential direction Y) as weak portions that promote deformation of the rear wall surface portion 52a. Each slit 54 is formed so as to extend in the axial direction X from the end portion on the opening 55 side in the axial direction X in the rear wall surface portion 52a toward the opposite opening 55 side. The end of each slit 54 on the side opposite to the opening 55 is located on the side opposite to the opening 55 in the axial direction X from the center of the rear wall surface portion 52a. Each slit 54 in the rear wall surface portion 52a is disposed between the engaging portions 53 adjacent in the long side direction (circumferential direction Y).

  A similar slit 54 is also provided in each corner portion between the rear wall surface portion 52a and the pair of side wall surface portions 52c and 52d. A similar slit 54 may be provided in one or both of the side wall surface portions 52c and 52d.

  A reinforcing belt 58 that covers the slit 54 from the outside is provided on the outer peripheral surface of the peripheral wall 52 so as to extend in the circumferential direction Y. The reinforcing belt 58 is made of a metal such as stainless steel. The thickness of the reinforcing belt 58 is, for example, less than 1 mm.

  The reinforcing belt 58 is wound around the outer peripheral surface of the peripheral wall 52 over the entire periphery. A fixing bracket (not shown) is provided at one end of the reinforcing belt 58, and the other end of the reinforcing belt 58 is fixed to the fixing bracket, so that the endless shape is obtained. The peripheral wall 52 is surrounded by the reinforcing belt 58. In the present embodiment, the fixing bracket of the reinforcing belt 58 is disposed along the outer surface of the front wall surface portion 52b.

  The reinforcing belt 58 is attached to the peripheral wall 52 in a tensioned state without slackening, and the inner peripheral surface of the reinforcing belt 58 is fitted to the outer peripheral surface of the peripheral wall 52. In the axial direction X of the peripheral wall 52, the width of the reinforcing belt 58 is shorter than the length of the slit 54. Further, in the axial direction X of the peripheral wall 52, the width of the reinforcing belt 58 is shorter than half of the width of the rear wall surface portion 52a. The reinforcing belt 58 is disposed between the engaging portion 53 and the opening 55 in the axial direction X of the peripheral wall 52, more specifically, at a position along the opening 55 side end of the peripheral wall 52.

  Thus, the vicinity of the end portion on the side of the axial X opening 55 of each slit 54 is covered from the outside by the reinforcing belt 58. Further, each slit 54 is disposed so as to protrude in the axial direction X from the reinforcing belt 58 to the side opposite to the opening 55.

  The lid member 60 includes a lid portion 61 that closes the opening 55 of the case body 50, and a peripheral wall portion 62 that extends from the peripheral portion of the lid portion 61 toward the bottom wall 51 in the axial direction X.

  The lid portion 61 is disposed along a surface inclined toward the vehicle body upper side from the vehicle body side toward the vehicle body rear side, and the outer surface of the lid portion 61 is disposed so as to face the vehicle body rear lower side (see FIG. 2). The lid 61 has an upper end 61a with an increased inclination angle with respect to the horizontal direction of the vehicle body (see FIG. 2). The upper end 61a of the lid 61 is disposed on substantially the same plane as the lower end of the instrument panel 2 so as to fill a notch 2d provided in the lower end of the instrument panel 2 (see FIG. 1) (see FIG. 1). 2).

  The lid portion 61 is provided with a breakage accelerating portion 66, whereby the breakage of the lid portion 61 is promoted by an increase in internal pressure when the bag 70 is inflated in the case 48.

  The peripheral wall portion 62 of the lid member 60 is configured to be fitted to the outside of the peripheral wall 52 of the case body 50. The peripheral wall portion 62 includes a rear surface portion 62a that is overlaid on the outside of the rear wall surface portion 52a of the case body 50, a front surface portion 62b that is overlaid on the outside of the front wall surface portion 52b of the case body 50, and a pair of side wall surface portions 52c of the case body 50. , 52d is provided with a pair of side surface portions 62c, 62d.

  A plurality of extending portions 62e extending toward the counter lid portion 61 in the axial direction X are provided on the rear surface portion 62a of the peripheral wall portion 62 corresponding to the engaging portions 53 of the case main body 50, respectively. Each extension 62e is provided with a through hole 63 into which the engaging portion 53 is engaged. The extension part 62e and the through hole 63 are similarly provided on the front face part 62b of the peripheral wall part 62.

  A plurality of slits 64 corresponding to the slits 54 of the case body 50 are provided in the peripheral wall portion 62 of the lid member 60. The plurality of slits 64 are provided at intervals in the circumferential direction Y at the rear surface portion 62a and at each corner portion between the rear surface portion 62a and the pair of side surface portions 62c and 62d.

  In the circumferential direction Y, each slit 64 in the rear surface portion 62a is disposed in the adjacent extension portion 62e. Each slit 64 is formed so as to extend in the axial direction X, and is open to the side opposite to the cover 61.

  In addition, when the slit 54 is provided also in the side wall surface parts 52c and 52d of the case main body 50, the slit 64 may be provided also in the side parts 62c and 62d of the cover member 60 according to this.

  When the opening 55 of the case body 50 is closed by the lid 61 of the lid member 60 and the corresponding engaging portions 53 of the case body 50 are engaged with all the through holes 63 of the lid member 60, FIG. Thus, the case 48 in a state where the lid member 60 is assembled to the case body 50 is obtained.

  In this assembled state, the reinforcing belt 58 wound around the peripheral wall 52 of the case main body 50 is covered from the outside by the peripheral wall portion 62 of the lid member 60. In this assembled state, the slit 64 of the lid member 60 is aligned with the slit 54 of the case body 50 in the circumferential direction Y.

  In the knee airbag device 1 configured as described above, when gas is supplied from the inflator 72 to the bag 70 surrounded by the peripheral wall 52 of the case main body 50 at the time of impact load input such as a vehicle collision, the bag expands. The bag is deployed toward the opening 55 of the peripheral wall 52 and breaks through the lid 61. As a result, as shown in FIG. 2, in the vehicle interior space S2, the bag 70 is deployed between the instrument panel 2 and the occupant's knee N1, so that the occupant's knee N1 with respect to the vehicle body moves toward the front side of the vehicle body. Relative movement is suppressed.

  At this time, a large internal pressure is applied to the peripheral wall 52 of the case main body 50 from the inflated bag 70, but the peripheral wall outward of the case 48 is provided by the reinforcing belt 58 stretched outside the peripheral wall 52 as shown in FIG. The deformation of 52 is effectively suppressed. In addition, since the reinforcing belt 58 is provided along the end of the peripheral wall 52 on the axial direction X opening 55 side, the opening 55 side portion that is more easily deformed than the bottom wall 51 side is formed by the reinforcing belt 58. It can be effectively reinforced. Further, as shown in FIG. 4, since the reinforcing belt 58 is covered from the outside by the peripheral wall portion 62 of the lid member 60, it is possible to surely prevent the reinforcing belt 58 from dropping off or being damaged. Reinforcement can be achieved reliably.

  Therefore, according to the present embodiment, although the slit 54 is formed in the peripheral wall 52, it is possible to effectively suppress a decrease in the proof stress of the peripheral wall 52 against the internal pressure when the bag 70 is inflated. Therefore, when the bag 70 is inflated and deployed, a favorable reaction force from the peripheral wall 52 to the bag 70 can be obtained, whereby the bag 70 can be easily deployed in a predetermined manner as shown in FIG. Therefore, the occupant's knee N1 can be effectively protected by the normally deployed bag 70.

  Further, according to the knee airbag device 1 according to the present embodiment, if the movement of the occupant's knee N1 to the front side of the vehicle body is not sufficiently restricted, for example, as indicated by a two-dot chain line in FIG. The passenger's knee N1 may collide with the case 48 via the instrument panel 2. In this case, the occupant's knee N1 is likely to collide with the rear wall surface portion 52a of the case body 50 and the rear surface portion 62a of the lid member 60 that are arranged to face the rear side of the vehicle body.

  In this case, as described above, the plurality of slits 54 are provided in the rear wall surface 52a of the case body 50 and the corner portions on both sides thereof, and the plurality of slits 54 are also provided on the rear surface portion 62a of the lid member 60 and the corner portions on both sides thereof. By providing the slit 64, the peripheral wall 52 of the case main body 50 and the peripheral wall portion 62 of the lid member 60 are deformed inward of the case 48, particularly at the rear wall surface portion 52a, the rear surface portion 62a, and its peripheral portion. Can be promoted.

  At this time, since an impact is applied to the peripheral wall 52 of the case body 50 from the outside, the reinforcing belt 58 provided on the outer side of the peripheral wall 52 does not perform a reinforcing function for the peripheral wall 52. Further, as described above, the slit 54 that is longer than the width of the reinforcing belt 58 is formed in the peripheral wall 52, so that the rigidity of the peripheral wall 52 is effectively reduced.

  In addition, as the peripheral wall 52 is deformed, the gap between the outer peripheral surface of the peripheral wall 52 and the reinforcing belt 58 is enlarged, so that the tension of the reinforcing belt 58 is reduced and the reinforcing function by the reinforcing belt 58 is further restricted. Therefore, the deformation of the peripheral wall 52 is further promoted. Further, the deformation of the peripheral wall 52 of the case body 50 is promoted in this way, and the deformation of the peripheral wall portion 62 of the lid member 60 toward the inside of the case 48 is also promoted when the reinforcing belt 58 is loosened.

  Accordingly, the peripheral wall 52 of the case body 50 and the peripheral wall portion 62 of the lid member 60 are effectively deformed, so that the impact applied from the case 48 to the occupant's knee N1 can be effectively reduced.

  Furthermore, the slits 54 and 64 for promoting the deformation of the peripheral wall 52 of the case body 50 and the peripheral wall portion 62 of the lid member 60 due to an impact from the outside, and the reinforcing belt 58 for suppressing the deformation of the peripheral wall 52 due to internal pressure, Since it is provided so as to overlap in the radial direction of the peripheral wall 52, there is no need to expand the layout space of the peripheral wall 52, the reinforcing belt 58 and the peripheral wall portion 62 in the axial direction X. Therefore, the case 48 can be configured to be compact in the longitudinal direction of the vehicle body, and thereby, in the instrument panel inner space S1, a narrow vehicle longitudinal direction space between the drive unit 30 of the power steering mechanism and the instrument panel 2 is used. Thus, the case 48 can be disposed.

  Further, as shown by a two-dot chain line in FIG. 2, when the occupant's knee N1 moves relative to the vehicle body front side relative to the vehicle body, the case 48 interposed between the drive unit 30 and the occupant's knee N1 is By effectively deforming as described above, the impact applied from the drive unit 30 to the occupant's knee can be effectively absorbed.

[Second Embodiment]
The knee airbag device 101 according to the second embodiment will be described with reference to FIG. In addition, about the component similar to 1st Embodiment, while attaching | subjecting the same code | symbol in FIG. 5, the description is abbreviate | omitted.

  In the second embodiment, the case 48 containing the bag 70 and the inflator 72 is disposed adjacent to the vehicle body rear side of the drive unit 30 of the electric power steering mechanism, and the drive unit 30 and the case 48 are arranged in the vertical direction of the vehicle body. Are arranged at substantially the same height. The case 48 is attached to the motor case 32 of the drive unit 30 via a bracket 128, for example.

  In the second embodiment, the rear wall surface portion 52 a of the case 48 is disposed close to the front side of the vehicle body at the front end portion of the column cover 20. Therefore, as shown by a two-dot chain line in FIG. 5, when the column cover 20 moves together with the steering wheel 10 and the upper column 17 of the steering column 16 to the front side of the vehicle body, the front end portion of the column cover 20 or the operation lever. 44 may collide with the rear wall surface portion 52 a of the case 48.

  At this time, since the case 48 is provided with the slits 54 and 64 described in the first embodiment, deformation into the case 48 is effectively promoted, so that the collapse movement of the column cover 20 and the like is performed. It is possible to suppress inhibition by interference with the case 48. Therefore, the impact applied to the occupant due to the collision with the steering wheel 10 can be effectively mitigated.

  Similarly to the first embodiment, when the occupant's knee N1 collides with the case 48, the deformation of the case 48 is effectively promoted, thereby effectively mitigating the impact applied to the occupant's knee N1. be able to. Further, as in the first embodiment, when the bag 70 in the case 48 is inflated, the outward deformation of the case 48 is effectively suppressed by the reinforcing belt 58, so that the reaction from the case 48 to the bag 70 occurs. A force can be obtained satisfactorily, whereby the bag 70 can be easily inflated and deployed normally.

  While the present invention has been described with reference to the above-described embodiments, the present invention is not limited to the above-described embodiments.

  For example, in the above-described embodiment, the example in which the reinforcing belt 58 is provided over the entire circumference of the peripheral wall 52 of the case body 50 has been described. However, the reinforcing belt 58 may be provided in a part in the circumferential direction. In this case, both ends of the reinforcing belt 58 may be fixed to the peripheral wall 52 by some fixing means.

  As described above, according to the present invention, the case of the knee airbag device can be reduced in size, and the case can be applied from the case to the occupant's knee while ensuring the strength of the case against the internal pressure generated when the bag is inflated and deployed. Since the impact load can be effectively reduced, the impact load may be suitably used in the manufacturing industry of automobiles equipped with a knee airbag device.

1,101 knee airbag device 2 instrument panel 6 instrument panel member (instrument panel member)
8 Seat of driver's seat 10 Steering wheel 12 Steering support mechanism 14 Steering shaft 16 Steering column 17 Upper column 18 Lower column 20 Column cover 28 Bracket 30 Electric power steering mechanism drive unit 32 Motor case 34 Warm wheel case 40 Tilt mechanism 44 Operation lever 48 Case 50 Case body 51 Bottom wall 52 Peripheral wall 52a Rear wall surface portion 52b Front wall surface portion 52c, 52d Side wall surface portion 53 Engagement portion 54 Slit (fragile portion)
55 Opening 58 Reinforcement belt (reinforcement member)
60 Lid member 61 Lid part 62 Peripheral wall part (covering part)
64 slit 70 bag 72 inflator (inflation means)
N1 Crew's knees S1 Instrument panel space S2 Car interior space

Claims (9)

A case having a peripheral wall disposed in the instrument panel; a bag housed in the case so as to be surrounded by the peripheral wall; and inflating means for inflating the bag and deploying the bag toward one side in the axial direction of the peripheral wall. A knee airbag device comprising:
The peripheral wall is provided with a plurality of fragile portions at intervals in the circumferential direction,
A knee airbag device, wherein a reinforcing member that covers the plurality of fragile portions from the outside is provided on an outer peripheral surface of the peripheral wall so as to extend in a circumferential direction. The peripheral wall is composed of a plurality of wall surfaces connected to each other through a corner portion,
The knee airbag device according to claim 1, wherein the fragile portion is provided on at least one predetermined wall surface portion of the plurality of wall surface portions.   The knee airbag device according to claim 2, wherein the fragile portion is further provided in a corner portion adjacent to one side or both sides of the predetermined wall surface portion in the circumferential wall.   4. The knee airbag device according to claim 2, wherein the fragile portion is provided on a plurality of the wall surfaces adjacent to each other on the peripheral wall. 5.   The knee airbag device according to any one of claims 1 to 4, wherein the reinforcing member is provided over the entire circumference of the peripheral wall.   The knee airbag device according to any one of claims 3 to 5, wherein the fragile portion is a slit extending in an axial direction of the peripheral wall.   The knee airbag device according to claim 6, wherein the slit has a length larger than a width of the reinforcing member in an axial direction of the peripheral wall. The case includes a case main body having the peripheral wall, and a lid member that closes an opening formed at one axial end of the peripheral wall.
A plurality of engaging portions that can be engaged with the lid member are provided on the peripheral wall at intervals in the circumferential direction.
The reinforcing member is provided between the engagement portion and the opening in the axial direction of the peripheral wall,
The knee airbag device according to any one of claims 1 to 7, wherein the lid member includes a covering portion that covers the reinforcing member from the outside. In the instrument panel, a drive unit of a power steering mechanism is disposed,
The knee airbag device according to any one of claims 1 to 8, wherein the case is disposed adjacent to a vehicle body rear side of the drive unit.

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