Actuator for airbag device

Abstract

The actuator (A) is attached to the housing portion (11) side and connects a connection means (27) extending from the airbag (20). The actuator is provided with: a holding unit (45) that holds the igniter (37); and a cover section (55) disposed on the other end side of the holding section so as to face the igniter. The holding part has a cylindrical part (47) that covers at least the entire circumference of the base side of the igniter. The cover portion has: a top wall portion (56) facing the igniter; and a peripheral wall section (58) that covers the inner peripheral side of the cylindrical section in a cylindrical shape extending from the peripheral edge of the ceiling wall section. When the top wall portion receives the pressure of the combustion gas generated during the operation of the igniter, the cover portion can release the connection with the connection unit by separating the peripheral wall portion from the cylindrical portion and moving the top wall portion.

Description

Technical Field

[0001] The present invention relates to an actuator for an airbag device for controlling the inflation state of an airbag. Background Art

[0002] Currently, regarding the airbag device, as an actuator for controlling the inflation state of the airbag, there is a structure shown in Japanese Patent Gazette No. 2023-90502. Regarding the current actuator, a cover portion arranged in a manner opposite to the igniter is installed on a retaining portion of a structure that retains an igniter (squib) on one end side and leaves the other end side open. Regarding the actuator, the cover portion has: a flat top wall portion; and two legs extending from the top wall portion, and the cover portion is installed on the other end side of the retaining portion by engaging a locking protrusion provided on the front end side of the leg portion with a locking recess provided on the retaining portion side. In addition, regarding the actuator, the connecting member is connected by inserting the front end side of the connecting member extending from the airbag into the area between the top wall portion of the cover portion and the retaining portion. In the conventional actuator, the pressure of the combustion gas generated when the igniter is operated is used to press the top wall portion, thereby releasing the engagement between the locking recess and the locking projection, thereby releasing the connection with the connection unit.

[0003] However, the current actuator is formed into a structure in which the connecting member is connected by inserting the connecting member through the portion between the top wall portion of the cover and the retaining portion, that is, a gap for inserting the connecting member is formed between the top wall portion of the cover and the front end of the retaining portion. In addition, the current actuator is formed into a structure in which the cover is connected to the retaining member by two legs extending from the top wall portion. That is, the retaining portion is not a structure closed by the cover. Therefore, during operation, from the viewpoint of quickly pressing the top wall portion by the pressure of the combustion gas generated from the igniter, there is room for improvement in improving the airtightness in the state where the cover is installed on the retaining portion (vehicle-mounted state). Summary of the invention

[0004] An object of the present invention is to provide an actuator for an airbag device that can ensure good airtightness and can quickly release the connection with a connecting member extending from an airbag during operation.

[0005] The actuator for the airbag device of the present invention is formed into the structure shown below:

[0006] An actuator for an airbag device is installed on the storage portion side for storing a folded airbag.

[0007] The structure is formed such that the inflation state of the airbag can be controlled by connecting with a connecting unit extending from the airbag and maintaining or releasing the connection state with the connecting unit, and

[0008] The invention comprises: an igniter; a holding portion which holds the igniter at one end; and a cover portion which is arranged at the other end of the holding portion in a manner opposite to the igniter, wherein:

[0009] The holding portion includes a cylindrical portion capable of covering at least the side of the base portion of the igniter over the entire circumference.

[0010] The cover has: a top wall portion, which is arranged opposite to the igniter; and a peripheral wall portion, which is arranged to cover the inner peripheral side or the outer peripheral side of the cylindrical portion in a cylindrical shape extending from the peripheral edge of the top wall portion, and the cover is formed into a structure that closes the other end side of the holding portion, and,

[0011] The structure is formed so that the peripheral wall portion is mounted on the holding portion by being locked to the cylindrical portion. When mounted on the holding portion, the cylindrical portion or the peripheral wall portion can be maintained in an inserted state into the insertion hole formed on the front end side of the connecting unit.

[0012] The structure is formed such that when the pressure of the combustion gas generated when the igniter is operated is received by the top wall portion, the connection with the connection unit can be released by separating the peripheral wall portion from the cylindrical portion and moving the top wall portion.

[0013] The actuator for the airbag device of the present invention is formed into the following structure, that is, the cover part is installed on the holding part in such a way that the cylindrical peripheral wall part extending from the peripheral edge of the top wall part is arranged on the inner peripheral side or the outer peripheral side of the cylindrical part that covers the side of at least the base side of the igniter all around the entire circumference in the holding part. That is, in the state that the cover part is installed on the holding part, the periphery of the igniter is covered by the top wall part and the peripheral wall part or the cylindrical part of the holding part without any gap. Therefore, the airtightness is good, and when the igniter is working, the top wall part can be quickly pressed by the generated combustion gas, and the connection with the connection unit extending from the airbag can be quickly released.

[0014] Therefore, with the actuator for the airbag device of the present invention, good airtightness can be ensured, and the connection with the connection member extending from the airbag can be quickly released during operation.

[0015] In addition, in the actuator for the airbag device of the present invention, the cover portion is structured such that when the pressure of the combustion gas is borne by the top wall portion, the peripheral wall portion is separated from the cylindrical portion and the top wall portion is moved. That is, in the actuator for the airbag device of the present invention, the cover portion is structured so that it can be removed from the retaining portion without damaging the peripheral wall portion. Therefore, compared with the cover portion of the current actuator structured so that two legs extend from the top wall portion, the cover portion does not have a portion that is greatly protruding locally, and can suppress damage when it is removed from the retaining portion and scattered.

[0016] Furthermore, with respect to the actuator for the airbag device of the present invention, if a structure is formed so that the peripheral wall portion is arranged on the inner peripheral side of the cylindrical portion, and the side surface of the igniter is seamlessly covered by the area on the front end side, the side surface of the igniter is seamlessly covered by the peripheral wall portion extending from the top wall portion, so that the combustion gas generated when the igniter is working will not be directed toward the side of the igniter, but can be quickly directed toward the top wall portion side, thereby forming a preferred embodiment.

[0017] Furthermore, with respect to the actuator for the airbag device of the above-mentioned structure, if the cover portion is formed so as to be hemispherically curved from the peripheral wall portion to the inner peripheral surface side of the top wall portion, then when the combustion gas presses on the top wall portion, the pressure can be roughly evenly applied to the hemispherically curved area, thereby forming a preferred embodiment. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram showing a steering wheel airbag device using an actuator as one embodiment of the present invention.

[0019] Figure 2 yes Figure 1 A longitudinal sectional view of a steering wheel airbag device.

[0020] Figure 3 is Figure 1 A partially enlarged bottom view showing an inflator and an actuator of an embodiment in a steering wheel airbag device.

[0021] FIG. 4A is a schematic diagram showing an airbag used in the airbag device, and FIG. 4B and FIG. 4C are schematic diagrams showing the area around the exhaust hole of the airbag.

[0022] Figure 5 yes Figure 3 FIG. 2 shows a partially enlarged bottom view of the actuator.

[0023] FIG6A is a schematic perspective view of the actuator according to the embodiment as viewed from the cover portion side, and FIG6B is a schematic perspective view of the actuator according to the embodiment as viewed from the holding portion side.

[0024] Figure 7 It is a schematic exploded perspective view showing a cover portion and a holding portion in the actuator according to the embodiment.

[0025] Figure 8 It is a longitudinal sectional view along the left-right direction of the actuator according to the embodiment.

[0026] Fig. 9 yes Figure 8 The present invention is a longitudinal sectional view of the actuator along the front-rear direction, and is a view showing a base side portion of the peripheral wall portion of the cover portion.

[0027] FIG10A is a longitudinal sectional view of a cover portion of the actuator according to the embodiment, and FIG10B is a longitudinal sectional view of a holding portion of the actuator according to the embodiment that holds an igniter.

[0028] Fig.11 It is a partially enlarged longitudinal sectional view showing a locking projection and a locking recess in the actuator according to the embodiment.

[0029] Fig.12 It is a partially enlarged cross-sectional view showing a locking protrusion provided on the cover portion and a locking recess provided on the holding portion in the actuator according to the embodiment.

[0030] A and B of FIG. 13 are longitudinal cross-sectional views showing the actuator of the embodiment before and after operation. DETAILED DESCRIPTION

[0031] Hereinafter, an embodiment of the present invention will be described based on the drawings. In the embodiment, an actuator A for an airbag device M mounted on a steering wheel W is used as an example for description. Figure 1 , 2 As shown, the steering wheel W includes: a steering wheel body 1; and an airbag device M, which is arranged on the upper part of the boss portion B in the center of the steering wheel body 1. In the embodiment, the steering wheel body 1 includes: an annular portion R to be gripped during steering operation; a boss portion B, which is arranged approximately in the center of the annular portion R and connected to the steering shaft SS; and a predetermined number of spokes, which are not shown in the figure, and connect the boss portion B and the annular portion R.

[0032] In the embodiment, unless otherwise stated, the front-rear / up-down / left-right directions are based on the straight-line steering operation of the steering wheel W mounted on the vehicle. Figure 2 ) along the axial direction is set as the up-down direction, the front and back of the vehicle in the direction perpendicular to the steering axis SS is set as the front-to-back direction, and the left and right of the vehicle in the direction perpendicular to the steering axis SS is set as the left-right direction, thereby indicating the front-to-back / up-down / left-to-right directions.

[0033] like Figure 1 , 2 As shown, the steering wheel body 1 includes: a core 2 made of a metal such as an aluminum alloy; a cover 3 made of a synthetic resin; and a lower cover 4 made of a synthetic resin, which covers the lower part of the boss portion B. The core 2 is arranged to connect the annular portion R and the boss portion B. The cover 3 covers the core 2 at the annular portion R and the spoke portion (not shown).

[0034] like Figure 2As shown, the airbag device M includes: an airbag 20; an inflator 9, which supplies inflation gas to the airbag 20; a housing 11 as a storage portion, which stores and retains the folded airbag 20 and the inflator 9; an airbag cover 15, which covers the folded airbag 20; and a retaining member 7, which is used to install the airbag 20 and the inflator 9 on the housing 11.

[0035] like Figure 2 As shown, the inflator 9 has: a substantially cylindrical main body 9a having a plurality of gas discharge ports 9b; and a flange 9c for mounting the inflator 9 on the housing 11. The flange 9c is provided with through holes (not shown) for passing the bolts 7a of the retainer 7. The inflator 9 is electrically connected to a control device 90 described later.

[0036] In the embodiment, the inflator 9 of the airbag device M and the igniter 37 of the actuator A described later are configured to utilize Figure 1 The operation is controlled by the control device 90 shown.

[0037] like Figure 1 As shown, the control device 90 is electrically connected to an occupant detection sensor (e.g., a position detection sensor 92 capable of detecting the distance between the steering wheel W and the driver MD, and a weight detection sensor 93 capable of detecting the weight of the driver MD) capable of detecting the body shape and the sitting position of the driver MD as the occupant sitting in the driver's seat DS. In addition, the control device 90 is also electrically connected to a collision detection sensor 94 capable of detecting the acceleration and the acceleration direction of the vehicle. The control device 90 inputs the electrical signal from the position detection sensor 92, the weight detection sensor 93, or the collision detection sensor 94 to operate the inflator 9 of the airbag device M and to operate the igniter 37 of the actuator A. Moreover, in the case of the embodiment, the operation of the igniter 37 of the actuator A is controlled by the control device 90, and when the airbag 20 is expanded when the inflator 9 is operated, the increase in the internal pressure of the airbag 20 can be controlled. Specifically, the operation of the igniter 37 of the actuator A is controlled so that the inflation gas that has flowed into the airbag 20 is discharged to the outside of the airbag 20 , thereby inflating the airbag 20 in an appropriate inflation pattern.

[0038] like Figure 2 As shown in FIG. 1 , the housing 11 is made of a thin metal plate and has: a bottom wall portion 12 in a substantially rectangular plate shape, which allows the inflator 9 to be inserted from below and installed; and a peripheral wall portion 13 extending in the vertical direction from the outer peripheral edge of the bottom wall portion 12. The bottom wall portion 12 is formed with an insertion hole 12a, a mounting hole 12b, and a through hole 12c (see FIG. 1 ) in the front area of ​​an opening (reference numeral omitted) for inserting the main body 9a of the inflator 9. Figure 3 , 5, 6' B, 8, 9). The insertion hole 12a is a portion for inserting a connecting belt portion 27 extending from the airbag 20 as a connecting unit described later. The mounting hole 12b is a portion for mounting a mounting bracket portion 75 described later of the actuator A. The through hole 12c is a portion for passing a protruding piece 79 formed on the mounting bracket portion 75. On the upper end side of the peripheral wall portion 13, an unillustrated mounting piece extending outward is formed. In the embodiment, the airbag device M has the following structure, that is, the housing 11 is mounted and fixed to the core 2 of the steering wheel W using a mounting substrate of a horn switch mechanism mounted on the unillustrated mounting piece, thereby being mounted on the upper part of the boss portion B of the steering wheel body 1 installed on the steering shaft SS. In addition, the side wall portion 15c of the airbag cover 15 is mounted to the peripheral wall portion 13 of the housing 11 using rivets 16 or the like (refer to Figure 2 In the embodiment, the airbag 20 and the inflator 9 are arranged on the bolt 7a of the retainer 7 in the airbag 20 (see Figure 3 ) is mounted on the bottom wall portion 12 of the housing 11 as a mounting unit. Although the bolt 7a is not shown in detail, it penetrates the periphery of the inflow opening 21 of the airbag 20, which will be described later, the bottom wall portion 12 of the housing 11, and the flange portion 9c of the inflator 9 and is fixed by the nut 8.

[0039] The airbag cover 15 is made of synthetic resin and has: a top wall portion 15a, which covers the upper side of the airbag 20 accommodated in the housing 11; and a side wall portion 15c in a substantially square tube shape, which extends downward from the vicinity of the outer peripheral edge of the top wall portion 15a (see Figure 2 The top wall portion 15a is formed with two door portions 15b, 15b which are opened in the front-rear direction by being pressed by the inflated airbag 20.

[0040] The airbag 20 is formed into a bag-like shape made of a flexible woven fabric made of polyamide yarn, polyester yarn, etc. Figure 1 As shown by the double-dotted line, the airbag 20 allows the inflation gas to flow into the interior and expand in a manner that covers the upper surface of the steering wheel W. As shown in A of FIG. 4 , the airbag 20 has an inflow opening 21. The inflow opening 21 is used to insert the main body 9a of the inflator 9 from below. A mounting hole 22 for inserting the bolt 7a of the retainer 7 is formed on the periphery of the inflow opening 21. In addition, in the airbag 20, an exhaust hole 24 that opens in a circular shape is formed on the front side of the inflow opening 21. Between the exhaust hole 24 and the inflow opening 21, two insertion holes 23A and 23B are formed near the rear edge of the exhaust hole 24 and near the front edge of the inflow opening 21 (refer to A of FIG. 4 ). Each insertion hole 23A and 23B is used to insert the connecting belt portion 27 as a connecting unit. Each insertion hole 23A and 23B is formed in a slit shape roughly along the left and right direction in a manner that allows the connecting belt portion 27 to be inserted.

[0041] A baffle 26 is arranged on the outer peripheral side of the airbag 20 in such a manner as to block the exhaust hole 24. Similar to the airbag 20, the baffle 26 is formed of a flexible woven fabric composed of polyester yarn, polyamide yarn, etc. The outer shape of the baffle 26 is formed into an approximate rectangle capable of blocking the exhaust hole 24, so that one side (front side) separated from the inflow opening 21 is connected to the front edge side of the exhaust hole 24. In the baffle 26, the base 27a of the connecting belt portion 27 as a connecting unit connected to the actuator body 35 described later is connected to the side (rear side) on the side of the inflow opening 21 opposite to the side. The connecting belt portion 27 as the connecting unit is composed of a flexible narrow band-shaped body. The connecting belt portion 27 is arranged approximately along the front-to-back direction in a state in which the airbag 20 is flatly deployed. On the front end 27b side of the connecting belt portion 27, an annular portion 28 is formed through which a peripheral wall portion 58 (specifically, a base side portion 59) of a cover portion 55 described later of the actuator body 35 can be inserted. That is, in the embodiment, the annular portion 28 constitutes an insertion hole through which the base side portion 59 of the cover portion 55 can be inserted. The outer shape (inner diameter dimension) of the annular portion 28 is set to a dimension that allows the base side portion 59 of the cover portion 55 to be inserted, and does not allow the top wall portion 56 of the cover portion 55 described later to be inserted. The length dimension of the connecting belt portion 27 is set to a dimension that allows the airbag 20 to be inflated without hindrance even in a state where the connecting state with the actuator body 35 on the front end 27b side is maintained. The connecting belt portion 27 is inserted into the insertion holes 23A and 23B formed in the airbag 20 in a state where the outer peripheral side of the exhaust hole 24 is covered by the baffle 26. The base 27a side and the front end 27b side of the connecting belt portion 27 are arranged on the outer peripheral side of the airbag 20. The middle portion of the connecting belt portion 27 is arranged on the inner peripheral side of the airbag 20. And, while maintaining this state, the connecting belt portion 27 is folded together with the airbag 20 and stored in the housing 11. When mounted on the vehicle, the front end 27b of the connecting belt portion 27 protrudes from the insertion hole 12a of the housing 11. And, by inserting the peripheral wall portion 58 (base side portion 59) of the cover portion 55 of the actuator body 35 into the annular portion 28 provided at the front end 27b, the connecting belt portion 27 is connected to the actuator body 35 (refer to Figures 5 to 7 , 8 of A).

[0042] Furthermore, in the embodiment, the airbag 20 is inflated in two inflation modes, namely, an open mode in which the exhaust hole 24 is opened, and a closed mode in which the exhaust hole 24 is maintained in a closed state. Specifically, when the actuator body 35 is not operated and the connection between the front end 27b of the connecting belt portion 27 and the actuator body 35 is maintained (a state in which the base side portion 59 of the cover portion 55 is maintained inserted into the annular portion 28, refer to FIG. 13A ), the front end side of the baffle 26 is pressed by the base 27a of the connecting belt portion 27. Furthermore, as shown in FIG. 4B , in the closed mode in which the baffle 26 closes the exhaust hole 24, the airbag 20 is inflated. The actuator body 35 operates so that the cover portion 55 is detached from the later-described retaining portion 45 constituting the actuator body 35, and the peripheral wall portion 58 of the cover portion 55 is dropped from the annular portion 28. In a state where the connection between the connecting belt portion 27 and the actuator body 35 is released (refer to B of FIG. 13 ), the baffle 26 is pressed by the inflation gas to flow out from the exhaust hole 24 so that the baffle 26 opens. Furthermore, as shown in C of FIG. 4 , the airbag 20 is inflated in the opening mode in which the exhaust hole 24 is opened. The airbag 20 is inflated while maintaining the internal pressure in the closed mode. The airbag 20 is inflated while suppressing the increase in the internal pressure in the opening mode. The operation of the actuator body 35 is controlled by the control device 90. In the embodiment, when the control device 90 detects that the driver MD is too close to the steering wheel W based on a signal from the position detection sensor 92, or detects that the driver MD is small in size based on a signal from the weight detection sensor 93, the actuator body 35 is operated simultaneously with the operation of the inflator 9 or with a slight delay so as to reduce the internal pressure of the airbag 20 during inflation.

[0043] In the case of implementation, such as Figure 2 , 3 As shown, the actuator A is arranged in the area in front of the inflator 9. Figure 5 As shown in A and B of FIG. 6 , the actuator A includes: an actuator body 35 ; and a mounting bracket portion 75 for mounting the actuator body 35 on the housing 11 as a storage portion.

[0044] As shown in A and B of FIG6 , the outer shape of the actuator body 35 is formed into a substantially cylindrical shape. In the embodiment, the actuator body 35 is mounted on the housing 11 by the mounting bracket 75 so that the axial direction is substantially along the left-right direction. Figure 8As shown, the actuator body 35 includes: a holding portion 45; an igniter 37 held at a base side (left end 45b side in the embodiment) which is one end side of the holding portion 45; and a cover portion 55 which is arranged at the other end side (front end side, right end 45a side in the embodiment) of the holding portion 45 so as to face the igniter 37. The holding portion 45 and the cover portion 55 are made of a synthetic resin such as a polyamide resin kneaded with a reinforcing filler.

[0045] like Figure 8 As shown, the igniter 37 includes: a main body 38; and a pair of conductive pins 40, 40 extending to the left from the main body 38. The conductive pin 40 is arranged so that the front end side is exposed from the left surface side of the base 46 of the holding part 45 described later. The conductive pin 40 is a portion that electrically connects the connector (not shown) to the control device 90. Although the detailed illustration is omitted, the main body 38 contains a gas generator that can generate combustion gas. In the main body 38, the outer peripheral side of the gas generator is covered by a metal thin-walled cover 39 composed of aluminum alloy or the like. The main body 38 is operated when an operation signal from the control device 90 is input, so that the gas generator is burned. At this time, the cover 39 covering the outer peripheral side of the gas generator opens the area covered by the cover 55 side of the gas generator (the area on the right end surface 38a side of the main body 38, and the area of ​​the disc-shaped top plate 39a). Specifically, the region of the top plate portion 39a is broken starting from the vicinity of the center and divided into a plurality of regions to open radially (see Figure 8 The igniter 37 is integrally formed with the holding portion 45 by insert molding when the holding portion 45 is formed, and is held by the holding portion 45.

[0046] like Figure 8As shown in FIG. 10B, the retaining portion 45 includes: a base 46; and a cylindrical portion 47 extending from the base 46. The base 46 is a portion that is arranged on the base side (left end 45b side) and holds the igniter 37 (specifically, the area from the left end surface side of the main body 38 to the base side of the conductive pin 40). The cylindrical portion 47 can cover the lateral side of at least the base side of the igniter 37 (specifically, the main body 38) all around. In addition, a protrusion 45c for positioning relative to the mounting bracket portion 75 is formed on the outer peripheral surface side of the retaining portion 45. The protrusion 45c protrudes in an approximately rectangular shape at a position slightly to the left of the center of the retaining portion 45 in the left-right direction. As described above, the conductive pin 40 of the igniter 37 makes the front end side protrude from the left end surface side of the base 46 to the left. As an approximately cylindrical shape, as shown in B of FIG. 10 , the cylindrical portion 47 is configured to have a gap between it and the side surface 38b of the main body portion 38. The front end side (right end side) of the cylindrical portion 47 is open. In the case of the embodiment, the front end (right end 47c) of the cylindrical portion 47 is located slightly forward of the right end surface 38a of the main body portion 38 of the igniter 37. That is, the cylindrical portion 47 covers the side of the main body portion 38 all around. On the side of the inner peripheral surface 47a of the cylindrical portion 47, a locking recess 48 is formed for locking a locking protrusion 66 formed on the peripheral wall portion 58 of the cover portion 55 described later. The locking recess 48 is formed near the front end (right end 47c) of the cylindrical portion 47 so that the inner peripheral surface 47a is recessed. In the case of the embodiment, as Figure 7 As shown in FIG. 10B , the locking recess 48 is configured to be continuously recessed over the entire circumference of the cylindrical portion 47. More specifically, Fig.12 As shown in FIG. 1 , the locking recess 48 is formed so that the inner peripheral surface 47a of the cylindrical portion 47 is recessed in a cross section approximately in the shape of a letter "く" (the front end 48b of the recess located on the outermost side is arranged near the center in the left-right direction) so that the two inclined surfaces 48a, 48a are arranged side by side on the left and right sides. The recess amount L1 of the locking recess 48 is set to about 1 / 8 of the thickness dimension T1 of the cylindrical portion 47 (refer to FIG. Fig.12 The width dimension L2 of the locking recess 48 is set to be about 6 times the recess amount L1 and about 2 / 3 of the thickness dimension T1 of the tubular portion 47 (see Fig.12 ). Moreover, the inclined surface 48a has an inclination angle α (see Fig.12 ) is set to about 20°. In the embodiment, the front end face 50 formed on the front end (right end 47c) side of the cylindrical portion 47 is inclined relative to the axial direction of the retaining portion 45 (in line with the inner circumferential surface 47a) in a cross section substantially along the front-back direction so that the inner circumferential surface 47a side is located at the rightmost side. Specifically, the inclination angle β (refer to Fig.12) is set to about 60°. In the embodiment, in the front end face 50, the outer edge 50a on the outer peripheral surface 47b side is arranged at a position slightly to the right of the front end 48b of the recessed portion of the locking recessed portion 48 (refer to Fig.12 The outer edge 50a is arranged at a position substantially aligned with the right end surface 38a of the main body 38 of the igniter 37 in the left-right direction (see Fig.11 That is, the front end 48 b of the recessed portion of the locking recessed portion 48 is located slightly to the left of the right end surface 38 a of the main body portion 38 .

[0047] like Figure 8 As shown in FIG. 10A, the cover portion 55 includes: a top wall portion 56 disposed opposite to the igniter 37; and a cylindrical peripheral wall portion 58 extending from the peripheral edge of the top wall portion 56. The outer shape of the top wall portion 56 is formed in a substantially disk shape. In the embodiment, the outer diameter dimension D2 of the top wall portion 56 is set to be substantially the same as the outer diameter dimension of the retaining portion 45 (that is, the outer diameter dimension D1 of the cylindrical portion 47) (refer to FIG. 10A and B).

[0048] As shown in FIG. 10A , the outer shape of the peripheral wall portion 58 is formed into a substantially cylindrical shape with an opening on the left end side on the igniter 37 side. The peripheral wall portion 58 includes: a base side portion 59 located on the top wall portion 56 side; and a front end side portion 63 disposed on the igniter 37 side. The outer diameter dimension of the front end side portion 63 is set to be slightly smaller than that of the base side portion 59. The peripheral wall portion 58 is provided with a step portion 61 on the outer peripheral surface 58b side in such a manner that the inner peripheral surface 58a side is coplanar. Thus, the front end side portion 63 is set to be a small diameter relative to the base side portion 59. That is, the base side portion 59 is configured to be slightly thicker than the front end side portion 63. Moreover, in the embodiment, the front end side portion 63 is formed to cover the inner peripheral side of the cylindrical portion 47 of the retaining portion 45. The outer diameter dimension D3 of the front end side portion 63 is set to be substantially the same as the inner diameter dimension d1 of the cylindrical portion 47. The thickness dimension T2 of the front end portion 63 is set to be equal to the opening width dimension H of the gap between the cylindrical portion 47 and the main body portion 38 of the igniter 37. That is, the thickness dimension T2 of the front end portion 63 is set to a dimension that allows the front end portion 63 to be inserted into the gap between the cylindrical portion 47 and the main body portion 38 (see A, B and Fig.12 ). In addition, when the cover 55 is mounted on the holding portion 45, the front end portion 63 of the peripheral wall 58 is formed to cover the side surface 38b of the main body 38 of the igniter 37 without a gap (see Figure 8 ). In addition, Figure 8 , 11In the accompanying drawings, a small gap is shown between the side 38b of the main body 38 and the front end side portion 63, but the gap is very small in reality. The term "no gap" in this specification means that there is also a small gap between the side 38b of the main body 38 and the front end side portion 63 due to errors during manufacturing. In the embodiment, when the cover 55 is installed to the retaining portion 45 (when the locking protrusion 66 is locked to the locking recess 48), the front end surface (left end surface 63b) of the front end side portion 63 is arranged between the base 46 of the retaining portion 45 with a slight gap (refer to Fig.11 ).

[0049] A locking protrusion 66 is formed on the outer peripheral surface 63a side of the front end side portion 63 of the peripheral wall portion 58. The locking protrusion 66 is a portion that is inserted into and locked in the locking recess 48 formed on the inner peripheral surface 47a side of the cylindrical portion 47 of the retaining portion 45. The locking protrusion 66 is formed at the approximate center in the left-right direction of the front end side portion 63 so as to protrude outward from the outer peripheral surface 63a. In the embodiment, as shown in Figure 7 As shown in FIG. 1 , the locking projection 66 is configured to protrude continuously over the entire circumference of the front end side portion 63. The cross-sectional shape of the locking projection 66 along the direction side substantially in the left-right direction is formed into a flat, approximately trapezoidal shape. The width dimension L4 of the locking projection 66 is set to be substantially the same as the width dimension L2 of the locking recess 48 (refer to FIG. 1 ). Fig.12 The protrusion amount L3 of the locking protrusion 66 is set to about 1 / 2 of the depression amount L1 of the locking recess 48 (see Fig.12 ). In addition, the protrusion amount L3 of the locking protrusion 66 is set to about 1 / 10 of the thickness dimension T2 of the front end side portion 63. The locking protrusion 66 is configured to have inclined surfaces 66a, 66a on the right end side and the left end side. The inclined surface 66a is configured to correspond to the inclined surface 48a formed in the locking recess 48. The inclined angle γ of the inclined surface 66a relative to the outer peripheral surface 63a of the front end side portion 63 (refer to Fig.12 ) is set to about 20°. The outer shape of the locking protrusion 66 (the protrusion amount to the outside, the angle of the inclined surface 66a, the protrusion amount relative to the thickness dimension T2 of the front end side part 63, and the dimension difference of the recessed amount L1 relative to the locking recess 48) is designed so that when the actuator body 35 is in operation and the locking of the locking recess 48 is released, the damage of the front end side part 63 and the cylindrical part 47 of the holding part 45 can be suppressed, and the front end side part 63 can be separated from the cylindrical part 47 (so that the cover part 55 can be separated from the holding part 45).

[0050] The outer diameter D4 of the base side portion 59 of the peripheral wall portion 58 is set to about 4 / 5 of the outer diameter D2 of the top wall portion 56 (see A in FIG. 10 ). The base side portion 59 is a portion that is arranged to be exposed between the holding portion 45 and the top wall portion 56 when the cover portion 55 is attached to the holding portion 45 (see FIG. 10 ). Fig.11 ). In an embodiment, if Figure 8 , 9 As shown, the base-side portion 59 is inserted into the annular portion 28 formed on the front end 27 b side of the connecting belt portion 27 (connecting means) of the airbag 20 .

[0051] In addition, in the embodiment, the cover portion 55 is configured so that the inner peripheral surface 55a side from the peripheral wall portion 58 to the top wall portion 56 is curved in a hemispherical shape. Specifically, in the embodiment, the cover portion 55 is provided with a curved surface portion 70 that is curved in a hemispherical shape on the inner peripheral surface 55a side from the base side portion 59 to the top wall portion 56 (refer to A of FIG. 10 ). In the embodiment, the inner diameter dimension d2 of the curved surface portion 70 is set to be substantially the same as the outer diameter dimension D5 of the main body portion 38 of the igniter 37 (refer to A and B of FIG. 10 ). In addition, in the curved surface portion 70, the center side of the curved surface portion 70 is spaced apart from the main body portion 38 by a distance L5 (refer to FIG. 10 ) when the cover portion 55 is mounted on the retaining portion 45. Figure 8 ) is set to be slightly larger than the radius dimension of the main body 38 (ie, 1 / 2 of the outer diameter dimension D5).

[0052] The mounting bracket portion 75 is made of a thin metal plate. Figure 5 As shown in A and B of 6, the mounting bracket portion 75 includes: a main body portion 76, which is hung around the outer peripheral side of the holding portion 45 almost all around; and a mounting portion 77, which is arranged on both end sides of the main body portion 76. The mounting portion 77 is a portion fixed to the bottom wall portion 12 of the housing 11 by bolts in a two-layer overlapping state. The mounting portion 77 is formed with an insertion hole 77a through which the bolt 82 can be inserted. In the main body portion 76, a through hole 78 is formed in the area covering the lower surface side of the holding portion 45, through which the protrusion 45c formed on the holding portion 45 can pass. The through hole 78 opens in a substantially rectangular shape. In addition, a protruding piece 79 is formed on the right edge 76b side of the main body portion 76 and on the front end side. The protruding piece 79 protrudes upward on the bottom wall portion 12 side of the housing 11. The protruding piece 79 is inserted into the through hole 12c formed in the bottom wall portion 12. The protruding piece 79 is provided for positioning when the actuator body 35 is mounted on the bottom wall 12 by the mounting bracket portion 75. In addition, two restricting pieces 80, 80 are formed on both front and rear ends of the right edge 76a side of the main body portion 76 so as to extend to the right side (see Figure 5 The limiting piece 80 is arranged near the top wall 56 so as to cover the front and rear sides of the base side portion 59 of the cover 55 (see Figure 5 , 9 The restriction pieces 80, 80 are arranged to prevent the front end 27b side (the annular portion 28) of the connecting belt portion 27 from falling off from the actuator body 35 when the actuator body 35 is mounted on the vehicle.

[0053] Next, the installation of the actuator A and the airbag device M in the embodiment in the vehicle will be described. First, the airbag 20 is folded so that it can be stored in the housing 11 in a state where the retainer 7 is arranged inside. At this time, the connecting belt portion 27 is maintained in a state of being inserted into the insertion holes 23A and 23B and protruding from the insertion hole 23B to the front end 27b side, and the baffle 26 maintains a closed state of the exhaust hole 24. Then, the folded airbag 20 is stored in the housing 11. At this time, the front end 27b of the connecting belt portion 27 is protruded from the insertion hole 12a of the bottom wall portion 12. The base side portion 59 of the cover portion 55 of the actuator body 35 is inserted into the annular portion 28 formed at the front end 27b of the connecting belt portion 27. Next, the cover portion 55 in a state where the front end 27b (annular portion 28) of the connecting belt portion 27 is penetrated is attached to the retaining portion 45 in a state where the mounting bracket portion 75 is attached, and the actuator body 35 is formed. If the mounting portion 77 of the mounting bracket portion 75 is mounted on the bottom wall portion 12 using the bolt 82 and the nut 83, the actuator body 35 can be connected to the connecting belt portion 27 (connecting member). At the same time, the actuator A can be mounted on the housing 11. Next, the main body 9a of the inflator 9 is inserted from below. The inflator 9 and the airbag 20 are mounted on the housing 11 using the bolt 7a and the nut 8 of the retainer 7 protruding from the bottom wall portion 12. In addition, the airbag cover 15 is covered on the housing 11 and is mounted on the housing 11 using the rivet 16 or the like. Then, if the unillustrated horn switch mechanism is assembled to the unillustrated mounting piece of the housing 11, the airbag device M can be assembled. The airbag device M can be mounted on the steering wheel body 1 that is pre-fastened to the steering shaft SS using the unillustrated mounting substrate of the horn switch mechanism. Then, a connector (not shown) connected to the lead wire extending from the control device 90 is connected to the igniter 37 of the actuator body 35. When the lead wire (not shown) extending from the control device 90 is connected to the inflator 9, the airbag device M and the actuator A can be mounted on the vehicle.

[0054] In the airbag device M of the embodiment, when the inflation gas is discharged from the gas discharge port 9b of the inflator 9, the inflation gas flows into the interior to inflate the airbag 20. The airbag 20 presses the door portions 15b, 15b of the airbag cover 15 to open it, and protrudes from the housing 11, as shown in FIG. Figure 1As shown by the double-dashed line, the expansion is completed in a manner that covers the upper surface of the steering wheel W substantially over the entire surface. Moreover, at this time, regarding the actuator body 35 of the actuator A, if the igniter 37 is operated by receiving the operation signal from the control device 90, the combustion gas G generated by the operation of the igniter 37 breaks through the cover 39 covering the outer peripheral side of the main body 38 to open it, and is ejected toward the cover 55 side. Moreover, the combustion gas G presses the top wall 56 of the cover 55. The cover 55 uses the top wall 56 to receive the pressure of the combustion gas G, and the locking state between the locking protrusion 66 and the locking recess 48 is released, and the peripheral wall 58 is separated from the cylindrical portion 47 and removed from the retaining portion 45. As shown in B of FIG. 13, the cover 55 falls off from the annular portion 28 provided on the front end 27b side of the connecting belt portion 27, and the connection state with the connecting belt portion 27 is released. 4C , the baffle 26 connected to the connecting belt portion 27 opens the exhaust hole 24 of the airbag 20 , and the inflation gas is discharged from the exhaust hole 24 .

[0055] Furthermore, regarding the actuator A of the embodiment, the cover 55 is mounted on the holder 45 by placing the cylindrical peripheral wall portion 58 extending from the peripheral edge of the top wall portion 56 on the inner peripheral side or the outer peripheral side (in the case of the embodiment, the inner peripheral side) of the cylindrical portion 47 that covers at least the side of the base side of the igniter 37 (specifically, the main body portion 38 of the igniter 37) over the entire circumference of the holder 45. That is, regarding the actuator A of the embodiment, in a state where the cover 55 is mounted on the holder 45, the periphery of the igniter 37 is covered by the top wall portion 56 and the peripheral wall portion 58 substantially without a gap. Therefore, the airtightness is good, and when the igniter 37 is operated, the top wall portion 56 can be quickly pressed by the generated combustion gas G. As a result, the connection with the connection belt portion 27 as the connection unit extending from the airbag 20 can be quickly released.

[0056] Therefore, the actuator A of the embodiment can ensure good airtightness and can quickly release the connection with the connecting belt portion 27 extending from the airbag 20 during operation.

[0057] In addition, regarding the actuator A of the embodiment, the cover 55 is configured such that when the pressure of the combustion gas G is received by the top wall 56, the peripheral wall 58 is separated from the cylindrical portion 47 and the top wall 56 is moved. That is, regarding the actuator A of the embodiment, the cover 55 is configured so as to be removed from the holder 45 without damaging the peripheral wall 58. Therefore, compared with the cover of the conventional actuator configured such that two legs extend from the top wall, the cover 55 does not have a portion that is greatly protruded locally, and can suppress damage when it is removed from the holder 45 and scattered.

[0058] In addition, regarding the actuator A of the embodiment, the peripheral wall portion 58 of the cover portion 55 is arranged on the inner peripheral side of the cylindrical portion 47 of the holding portion 45. In addition, the peripheral wall portion 58 is a structure in which the side 38b of the igniter 37 (main body 38) is covered without a gap by the area on the front end side (front end side portion 63). Therefore, the combustion gas G generated when the igniter 37 (main body 38) is operated will not be directed to the side of the main body 38, but can be quickly directed to the top wall portion 56 side. In addition, compared with the case of a structure in which the peripheral wall portion is arranged on the outer peripheral side of the cylindrical portion, the size of the cover portion 55 (specifically, the size of the peripheral wall portion 58) can be made compact. That is, the weight of the cover portion can be suppressed from increasing, so based on this point, the damage of the cover portion after scattering can also be further suppressed. In addition, if this point is not taken into consideration, a structure in which the peripheral wall portion is arranged on the outer peripheral side of the cylindrical portion of the holding portion can be used as the cover portion. In addition, when the peripheral wall portion is arranged on the inner peripheral side of the cylindrical portion of the holder, the side surface of the igniter may not be covered by the region on the front end side of the peripheral wall portion.

[0059] Furthermore, in the actuator A of the embodiment, the cover 55 is curved in a hemispherical shape from the peripheral wall portion 58 (specifically, the base side portion 59 on the top wall portion 56 side) to the inner peripheral surface 55a side of the top wall portion 56. Therefore, when the combustion gas G presses the top wall portion 56 during the operation of the igniter 37, the pressure can be applied substantially uniformly to the hemispherically curved region (curved surface portion 70).

[0060] In addition, regarding the actuator A of the embodiment, the cover 39 covering the outer peripheral side of the gas generating agent (not shown) of the igniter 37 is formed into the following structure, that is, when the igniter 37 is in operation, the area of ​​the disc-shaped top plate portion 39a covering the cover portion 55 side is broken from the center as a starting point, and is divided into a plurality of parts and opened radially. However, the inner peripheral surface 55a side (curved surface portion 70) of the cover portion 55 is curved in a hemispherical shape, and the area that contacts the trajectory when the cover 39 (top plate portion 39a) is opened does not have a locally protruding part. Therefore, the cover 39 (top plate portion 39a) can be suppressed from contacting the area on the inner peripheral surface side of the cover portion 55 during the opening, and the cover 39 (top plate portion 39a) can be quickly opened. In particular, regarding the actuator A of the embodiment, the inner diameter dimension d2 of the curved surface portion 70 is set to be substantially the same as the outer diameter dimension D5 of the main body portion 38 of the igniter 37. In addition, the spacing distance L5 between the central side of the curved surface portion 70 and the main body portion 38 when the cover portion 55 is mounted on the holding portion 45 is set to be slightly larger than the radius dimension (1 / 2 of the outer diameter dimension D5) of the main body portion 38. That is, with respect to the actuator A of the embodiment, when the disc-shaped top plate portion 39a arranged opposite to the top wall portion 56 in the cover 39 is broken with the vicinity of the center as a starting point and is divided into a plurality of parts to open radially, it is possible to reliably suppress contact with the inner peripheral surface 55a side of the cover portion 55 until the opening is substantially completed (see Figure 8 In addition, the volume of the space in the area surrounded by the main body 38 of the igniter 37 and the cover 55 (the space temporarily filled with the combustion gas G during operation) is set to the minimum required. Therefore, the pressure of the combustion gas G generated when the igniter 37 is operated can be efficiently applied to the cover 55 while suppressing the loss as much as possible.

[0061] Regarding the actuator A of the embodiment, the locking recess 48 formed on the inner peripheral surface 47a side of the cylindrical portion 47 of the holding portion 45 and the locking protrusion 66 formed on the peripheral wall portion 58 of the cover portion 55 (the outer peripheral surface 63a side of the front end side portion 63) are all formed on the cylindrical portion 47 or the front end side portion 63 throughout the entire circumference. Therefore, when the cover portion 55 is mounted on the holding portion 45, it is not necessary to consider the direction, etc., and the mounting workability is good. In addition, compared with the locking protrusion and the locking recess being provided Compared with the case where the locking projection 66 is placed locally, the protrusion amount of the locking projection 66 (the depression amount of the locking recess 48) can also be set relatively small. In particular, with respect to the actuator A of the embodiment, the locking projection 66 is formed into a structure in which the inclined surface 66a is arranged on both ends (the left end and the right end) of the peripheral wall portion 58 (the front end side portion 63) in the insertion direction of the cylindrical portion 47. Moreover, the inclination angle γ of the inclined surface 66a relative to the outer peripheral surface 63a is set small. In other words, The locking projection 66 is formed to be gently raised in the direction along the insertion direction of the front end side portion 63 toward the cylindrical portion 47. The locking recess 48 is also formed with an inclined surface 48a corresponding to the inclined surface 66a of the locking projection 66. Therefore, when the cover 55 is mounted on the retaining portion 45, if the top wall portion 56 is pressed toward the retaining portion 45 to move it, the locking projection 66 can be inserted into the locking recess 48 with a small force and locked to the locking recess 48. 8 periphery. In addition, when the igniter 37 is in operation, when the cover 55 moves with the combustion gas G pressing the top wall 56, the locking projection 66 can also be smoothly removed from the locking recess 48, and the damage of the locking projection 66 and the periphery of the locking recess 48 can be suppressed. The inclination of the front end surface 50 on the right end 47c side of the cylindrical portion 47 provided on the holding portion 45 is also formed in consideration of such installation workability and the detachment of the cover 55 when the igniter 37 is in operation.

[0062] In addition, if the above aspects are not taken into consideration, the locking projection and the locking recess may not be formed throughout the entire circumference. For example, the locking projection and the locking recess may be formed into a structure arranged at a plurality of locations in a radial shape. In addition, contrary to the embodiment, it may be formed into a structure in which the locking projection is arranged on the retaining portion side and the locking recess is arranged on the cover portion side. However, from the viewpoint of suppressing damage after scattering, it is preferably formed into a structure in which the locking projection is arranged closer to the cover portion side than the locking recess having a thinner area formed locally.

[0063] In the embodiment, as a connecting unit extending from the airbag 20, a connecting belt portion 27 composed of a flexible narrow band-shaped body is used. On the front end 27b side of the connecting belt portion 27, an annular portion 28 is arranged as an insertion hole. Moreover, in the embodiment, the outer shape (inner diameter dimension) of the annular portion 28 is set to a size that allows the base side portion 59 of the cover portion 55 to be inserted, and does not allow the top wall portion 56 of the cover portion 55 to be inserted. The outer shape (inner diameter dimension) of the annular portion is not limited to the embodiment. The outer shape (inner diameter dimension) of the annular portion can be set to a size that allows both the base side portion and the top wall portion of the cover portion to be inserted. With respect to the actuator A of the embodiment, the mounting bracket portion 75 on which the actuator body 35 is mounted has limiting pieces 80, 80 that cover the front and rear sides (both sides) of the base side portion 59 of the cover portion 55. Therefore, even if the outer shape (inner diameter) of the annular portion 28 is set larger, the annular portion 28 can be reliably prevented from falling off from the actuator body 35. Of course, the connecting unit may not be the belt-shaped body of the embodiment. As the connecting unit, a structure composed of a flexible belt-shaped body and having an insertion hole opened at the front end side can be used.

[0064] In addition, in the embodiment, as an airbag device using an actuator, an airbag device for a steering wheel is described as an example. However, the airbag device that can use the actuator of the present invention is not limited to the airbag device for a steering wheel. The actuator of the present invention can also be used for an airbag device for a passenger seat. In addition, in the embodiment, a structure is formed to control the internal pressure of the airbag using an actuator. However, the control of the inflation state of the airbag is not limited to the internal pressure control. For example, the actuator of the present invention can be used to control the inflation shape of the airbag.

Claims

1. An actuator (A) for an airbag device, which is mounted on a storage portion (11) for storing a folded airbag (20), wherein: The invention is formed into a structure in which the expansion state of the airbag can be controlled by connecting with a connecting unit (27) extending from the airbag and maintaining or releasing the connection state with the connecting unit, and The invention comprises: an igniter (37); a holding portion (45) which holds the igniter at one end; and a cover portion (55) which is arranged at the other end of the holding portion in a manner opposite to the igniter, wherein: The holding portion includes a cylindrical portion (47) capable of covering at least the side of the base of the igniter over the entire circumference. The cover portion comprises: a top wall portion (56) arranged opposite to the igniter; and a peripheral wall portion (58) arranged to cover the inner peripheral side or the outer peripheral side of the cylindrical portion in a cylindrical shape extending from the peripheral edge of the top wall portion, and the cover portion is formed into a structure that closes the other end side of the holding portion, and The structure is formed so that the peripheral wall portion is mounted on the holding portion by being locked to the cylindrical portion. When mounted on the holding portion, the cylindrical portion or the peripheral wall portion can be maintained in an inserted state into an insertion hole (28) formed on the front end side of the connecting unit. The structure is formed such that when the pressure of the combustion gas generated when the igniter is operated is received by the top wall portion, the connection with the connection unit can be released by separating the peripheral wall portion from the cylindrical portion and moving the top wall portion.

2. The actuator (A) for an airbag device according to claim 1, wherein: The peripheral wall portion (58) is arranged on the inner peripheral side of the cylindrical portion (47), and covers the side surface of the igniter (37) without a gap from the area on the front end side.

3. The actuator (A) for an airbag device according to claim 2, wherein: The cover portion (55) is configured such that the inner peripheral surface side from the peripheral wall portion (58) to the top wall portion (56) is curved in a hemispherical shape.

4. The actuator (A) for an airbag device according to claim 2, wherein: A locking recess (48) or a locking projection (66) capable of locking with each other is formed on the inner peripheral surface (47a) side of the cylindrical portion (47) or the outer peripheral surface (63a) side of the peripheral wall portion (58), respectively. The locking recess and the locking projection are formed over the entire circumference of the cylindrical portion or the peripheral wall portion.

5. The actuator (A) for an airbag device according to claim 4, wherein: The locking protrusion (66) is provided on the outer peripheral surface (63a) side of the peripheral wall portion (58). The locking recess (48) is provided on the inner peripheral surface (47a) side of the cylindrical portion (47).

Images