Side airbag device and manufacturing method thereof

Abstract

[Problem] To provide: a side airbag device capable of ensuring stability of the deployment behavior of an airbag; and a method for manufacturing the side airbag device. [Solution] A first aspect of the present invention is a side airbag device accommodated in a vehicle seat, the side airbag device comprising: an airbag that inflates / deploys toward the front of the vehicle, thereby protecting an occupant seated on the vehicle seat; an inflator that is fixed to a seat frame inside the vehicle seat and supplies inflation gas to the airbag; and a tether that is connected to the outer surface of the airbag and restricts the deployment behavior of the airbag. The airbag includes a main chamber that inflates / deploys mainly toward the front, and a pre-chamber that stores the inflator and inflates / deploys, before the main chamber inflates / deploys, toward the inner side in the vehicle width direction of the main chamber. A top end portion of the airbag is folded back downward when stored, thereby forming a top folded-back portion, and one end of the tether is connected to the vicinity of the top folded-back portion, while the other end is connected to the vicinity of the inflator. The tether has a structure having a release part that releases the coupling between the one end and the other end during deployment of the airbag.

Description

[Technical field]

[0001] The present invention relates to a side airbag device accommodated in a side portion of a vehicle seat, and a method for manufacturing the same. [Background technology]

[0002] It is well known that one or more airbag devices are provided in a vehicle to protect the occupant in the event of a vehicle accident. There are various types of airbag devices, such as a driver airbag device that deploys near the center of the steering wheel to protect the driver, a curtain airbag device that deploys downward inside the window to protect the occupant in the event of a lateral impact or rollover or overturning accident, and a side airbag device that deploys on the side of the occupant (the side of the seat) to protect the occupant in the event of a lateral impact of the vehicle. The present invention relates to a side airbag device provided in a vehicle seat and a method for manufacturing a side airbag device.

[0003] The side airbag device described in Patent Document 1 below includes a main airbag and an auxiliary airbag. The auxiliary airbag is inflated and deployed before the main airbag to restrain the occupant early. In addition to the invention described in Patent Document 1, many side airbag devices equipped with auxiliary airbags have been proposed.

[0004] However, in conventional side airbag devices, there is a risk that the deployment behavior of a plurality of airbags or an airbag having a plurality of chambers may become unstable. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2009-023494 A Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention has been made in consideration of the above circumstances, and has an object to provide a side airbag device that can ensure stability in the deployment behavior of the airbag, and a method for manufacturing the side airbag device. [Means for solving the problem]

[0007] In order to achieve the above object, a first aspect of the present invention is a side airbag device accommodated in a vehicle seat, the side airbag device comprising: an airbag that protects an occupant seated in the vehicle seat by inflating and deploying toward the front of the vehicle; an inflator that is fixed to a seat frame inside the vehicle seat and supplies inflation gas to the airbag; and a tether that is connected to the outer surface of the airbag and regulates the deployment behavior of the airbag. The airbag comprises a main chamber that inflates and deploys mainly toward the front; and a pre-chamber that accommodates the inflator and inflates and deploys prior to the main chamber on the inner side of the main chamber in the vehicle width direction. When the airbag is accommodated, an upper end portion is folded downward to form an upper folded portion, and one end of the tether is connected near the upper folded portion and the other end is connected near the inflator. The tether is structured to have a release portion that releases the connection between the one end and the other end when the airbag is deployed.

[0008] Here, it is said that the airbag inflates and deploys "towards the front of the vehicle", but this does not mean that it deploys only towards the front of the vehicle. Although it deploys generally towards the front, since it is an airbag that inflates with gas, it naturally also spreads upward and across the vehicle (thickness direction).

[0009] Further, the term "outer surface of the airbag" does not mean the inside of the bag-shaped airbag, but the outside of the airbag, and can be rephrased as "the surface of the airbag."

[0010] Furthermore, the "release portion" of the tether refers to a portion that releases the connection between one end and the other end of the tether, and includes cases where one end of both ends is released from the connection or where the middle portion of the tether breaks.

[0011] In the present invention, the upper end of the airbag is folded downward to form an upper folded portion, one end of a tether is connected to the upper folded portion, and the other end is connected to the vicinity of the inflator. In the early stage of airbag deployment, the deployment of the upper end of the airbag is restricted, and the lower part of the airbag is inflated and deployed first. Therefore, even if the occupant is in an out-of-position state, such as being seated close to the side support part of the vehicle seat, it is possible to prevent the upper end of the airbag from impacting the head or neck of the occupant. In addition, the lower part of the airbag deploys quickly and stably, which leads to a stable deployment behavior of the airbag as a whole.

[0012] As the airbag continues to deploy, the connection between the one end and the other end of the tether is released, i.e., the restriction on the upper folded part of the airbag is released, and the upper end of the airbag deploys upwards. This allows the airbag to fully deploy, providing a large area of ​​protection for the occupant.

[0013] The upper folded portion of the airbag may be formed on the outer side in the vehicle width direction. By folding the airbag on the outer side in the vehicle width direction, it is possible to prevent the upper end portion of the airbag from interfering with an occupant seated on the inner side in the vehicle width direction when the airbag is released from the folded state and attempts to deploy upward.

[0014] The inflator can be fixed to the inside of the seat frame by a stud bolt.

[0015] The other end of the tether may be coupled to the stud bolt.

[0016] Here, "connection" means, for example, forming a hole in the other end of the tether, allowing the hole to be hooked onto a stud bolt, and then tightening with a nut. By using a stud bolt fixed to the seat frame, the other end of the tether can be securely fixed.

[0017] The other end of the tether may be sewn adjacent to a stitch line that defines the periphery of the chamber of the airbag.

[0018] Here, the "sewing line forming the outer periphery of the chamber" can be, for example, a sewing line that connects the main chamber to the pre-chamber at the rear edge. By connecting the other end of the tether by sewing at the same time as sewing the outer periphery, it is not necessary to add an additional process. In addition, the tether can be attached at a stage before the inflator is inserted into the airbag, improving workability.

[0019] The one end of the tether may be connected to a front of the upper cuff of the airbag.

[0020] By positioning the connection position of one end (front end) of the tether closer to the front, the distance to the other end becomes longer, and the timing for releasing the tether, i.e., the release of the upper folded portion of the airbag, can be intentionally delayed.

[0021] The one end of the tether may be connected to the vicinity of the center in the front-rear direction of the upper folded portion of the airbag.

[0022] The one end of the tether may be connected to the rear of the top cuff of the airbag.

[0023] By positioning the connection position of one end (front end) of the tether toward the rear, the distance to the other end is shortened, and the timing for releasing the tether, i.e., the release of the upper folded portion of the airbag, can be intentionally accelerated.

[0024] The release portion may be configured as a temporary stitch for fixing the one end to the airbag, and the temporary stitch may be released or broken as the airbag is deployed.

[0025] The release portion may be a slit formed in the middle of the tether, and the tether may be configured to break from the slit as the airbag deploys.

[0026] Here, the slits can be formed, for example, so as to extend generally parallel to the width direction of the tether.

[0027] When a slit is used as the release portion, the force required to break the tether can be controlled by adjusting the length of the slit, etc., which contributes to stabilizing the breaking performance (release performance).

[0028] The main chamber can be divided into a front chamber portion located at the front side and a rear chamber portion located at the rear side, and configured so that air flows from the rear chamber portion into the front chamber portion.

[0029] A second aspect of the present invention is a manufacturing method for a side airbag device that has an airbag for protecting an occupant seated in a vehicle seat and is accommodated in the vehicle seat, the manufacturing method including the steps of: connecting, by sewing, a main chamber that inflates and deploys mainly forward and a pre-chamber that inflates and deploys prior to the main chamber on the inner side of the main chamber in the vehicle width direction; inserting an inflator that generates inflation gas into the pre-chamber; forming an upper folded portion by folding back an upper end portion of the airbag downward; and connecting one end of a tether to the upper folded portion and connecting the other end to the vicinity of the inflator. The tether has a release portion that releases the connection between the one end and the other end when the airbag is deployed.

[0030] The method according to the present invention may further include the steps of: fixing the inflator to an inner side of a seat frame with a stud bolt; and connecting the other end of the tether to the stud bolt.

[0031] The release portion may be a slit formed in the middle of the tether, and the tether may be configured to break from the slit as the airbag deploys.

[0032] The release portion may be configured as a temporary stitch for fixing the one end to the airbag, and the temporary stitch may be released or broken as the airbag is deployed.

[0033] In the following description of the present invention, when an occupant sits on a seat in a normal position, the direction in which the occupant faces is referred to as "forward" and the opposite direction is referred to as "rearward", and the coordinate axes are referred to as "front-rear direction". When an occupant sits on a seat in a normal position, the right side of the occupant is referred to as the "right direction", the left side of the occupant is referred to as the "left direction", and the coordinate axes are referred to as "left-right direction". When an occupant sits on a seat in a normal position, the direction of the occupant's head is referred to as "upward" and the direction of the occupant's waist is referred to as "downward", and the coordinate axes are referred to as "up-down direction". In the left-right direction, the area on the occupant's side from the side frame of the seat is referred to as "inner", and the area opposite the occupant from the side frame is referred to as "outer". [Brief description of the drawings]

[0034] [Figure 1] FIG. 1 is a perspective view mainly showing the external shape of a vehicle seat to which a side airbag device according to the present invention can be applied, and the airbag device is not shown. [Diagram 2] FIG. 2 is a perspective view showing an internal structure (seat frame) that functions as a framework of the vehicle seat shown in FIG. 1, and an airbag device is omitted from the illustration. [Diagram 3]FIG. 3 is a schematic side view of the side airbag device according to the present invention, showing the state in which the airbag device is housed as seen through from the outside in the vehicle width direction. [Figure 4] FIG. 4 is a plan view showing the panel configuration of an airbag according to the present invention, where (A) is a view from the outside (door side) in the vehicle width direction, and (B) is a view from the inside (passenger side). [Diagram 5] 5 is a schematic side view of the side airbag device according to the present invention, showing the state in which the airbag is deployed as viewed from the outside in the vehicle width direction. (A) shows the initial state of the airbag deployment, and (B) shows the state in which the airbag is fully deployed. [Figure 6] FIG. 6 is a schematic diagram showing the deployed state of the airbag corresponding to the cross section taken along the line A2-A2 of FIG. 5(B). [Figure 7] 7(A) and (B) are plan views showing a part of the manufacturing process of the side airbag device according to the present invention. [Figure 8] 8(A) and (B) are plan views showing a part of the manufacturing process of the side airbag device according to the present invention. [Figure 9] FIG. 9 is a plan view showing the structure of a side airbag device according to a first modified example of the present invention. [Figure 10] 10(A) and (B) are plan views showing the structures of side airbag devices according to second and third modified examples of the present invention. [Figure 11] 11(A) and (B) are plan views showing the structures of side airbag devices according to fourth and fifth modified examples of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0035] Fig. 1 is a perspective view mainly showing the external shape of a vehicle seat used in the passenger protection device according to the present invention, and an airbag device (20) is not shown. Fig. 2 is a perspective view showing an internal structure (seat frame) that functions as a framework of the vehicle seat shown in Fig. 1, and again, the airbag device (20) is not shown. Fig. 3 is a schematic side view of the passenger protection device according to the present invention, showing the state in which the airbag device 20 is housed on the side (near side) of the vehicle seat close to the door, as viewed from the outside in the vehicle width direction.

[0036] A vehicle seat to which the present invention is applicable is, when viewed as a whole, composed of a seat cushion 2 on which an occupant sits, a seat back 1 forming a backrest, and a headrest 3 connected to the upper end of the seat back 1, as shown in Figures 1 and 2.

[0037] A seatback frame 1f is provided inside the seatback 1, forming the framework of the seat, and a pad made of urethane foam or the like is provided on and around the seatback frame 1f, and the surface of the pad is covered with a skin 14 such as leather or fabric. A seating frame 2f is disposed on the bottom side of the seat cushion 2, and a pad made of urethane foam or the like is provided on the top surface and around the seatback frame 2f, and the surface of the pad is covered with a skin 14 such as leather or fabric (FIG. 4). The seating frame 2f and the seatback frame 1f are connected via a reclining mechanism 4.

[0038] 2, the seat back frame 1f is configured in a frame shape by seat frames 10 arranged spaced apart on the left and right and extending in the vertical direction, an upper frame connecting the upper ends of the seat frames 10, and a lower frame connecting the lower ends of the seat frames 10. The headrest 3 is configured by providing a cushion member on the outside of the headrest frame.

[0039] Fig. 4 is a plan view showing the panel configuration of the airbag 30 according to the present invention, where (A) is a view from the outside (door side) in the vehicle width direction, and (B) is a view from the inside (passenger side). Fig. 5 is a schematic side view of the side airbag device 20 according to the present invention, showing the state in which the airbag 30 is deployed as observed from the outside in the vehicle width direction. (A) shows the initial state of the airbag 30 deployment, and (B) shows the state in which the airbag 30 is fully deployed. Fig. 6 is a schematic view showing the deployed state of the airbag 30 corresponding to the cross section in the A2-A2 direction of Fig. 5(B).

[0040] The airbag device 20 according to the present invention includes an airbag 30 that protects an occupant seated in a vehicle seat by inflating and deploying toward the front of the vehicle, and an inflator 35 that is fixed to a seat frame 10 inside the vehicle seat and supplies inflation gas to the airbag 30. The airbag 30 (34, 36) is stored in a compressed state by folding or rolling it into a bellows shape or by any other suitable method.

[0041] As shown in Figures 4 to 6, the airbag 30 includes a main chamber 32 (32f, 32r) that inflates and deploys mainly forward, and a pre-chamber 34 that houses an inflator 35 and is inflated and deployed prior to the main chamber 32 on the inner side in the vehicle width direction of the main chamber 32.

[0042] 4 and 5, the pre-chamber 34 is configured such that the upper and lower regions are deployed to protrude further forward than the middle region of the vehicle. That is, the pre-chamber 34 has an inverted U-shape or an inverted C-shape with the middle region recessed rearward when viewed from the passenger side.

[0043] The front ends of the upper and lower regions of the pre-chamber 34 are molded to roughly coincide with the position of the front end of the main chamber 32, improving the unity of the airbag 30 including the main chamber 32 and the pre-chamber 34 and stabilizing the deployed shape of the entire airbag 30.

[0044] 4, an exhaust vent V0 for exhausting gas to the outside is formed at the front end of the main chamber 32. Note that, like the main chamber 32, it is also possible to form at least one exhaust vent for exhausting gas to the outside at the front end of the pre-push chamber 34.

[0045] As shown in FIG. 4, the chambers 32 (32f, 32r), 34 are defined by stitching S1, S2, S3.

[0046] As shown in Figs. 4 and 6, for example, a cylindrical inflator can be used as the inflator 35. Stud bolts 42 protrude from the outer periphery of the inflator 35. The stud bolts 42 are attached (fastened and fixed) to the seat frame 10 by nuts. The inflator 35 is formed with a plurality of gas outlets arranged in the circumferential direction, and gas is radially ejected from the gas outlets. Note that a diffuser for controlling the flow of gas can be provided as necessary. The inflator 35 is inserted into the pre-chamber 34 through an insertion hole 40.

[0047] An airbag control ECU mounted on the vehicle is electrically connected to the inflator 35. A satellite sensor for detecting a side collision is electrically connected to the airbag control ECU. The airbag control ECU can be configured to activate the inflator 35 when it detects a side collision based on a signal from the satellite sensor.

[0048] 6, the main chamber 32 is divided into a front chamber 32f and a rear chamber 32r by a partition panel 38, and an internal vent V2 is formed in the partition panel 38. In addition, an internal vent V1 is provided at the partition (boundary) between the main chamber 32 and the pre-chamber 34, through which inflation gas flows from the pre-chamber 34 into the main chamber 32.

[0049] 6, the pre-chamber 34 deploys overlapping the side frame 10 when viewed from the side of the vehicle, so that the pre-chamber 34 deploys toward the center of the seat reliably with the side frame 10 receiving the reaction force of the deployment of the pre-chamber 34. Even after deployment, the side frame 10 can receive pressure from the occupant, making it possible to reliably restrain the occupant toward the center of the seat.

[0050] On the other hand, the main chamber 32 deploys so as not to overlap the side frame 10 when viewed from the side of the vehicle. Therefore, the deployment of the main chamber 32 is not hindered by the side frame 10 or the pre-chamber 34, and the main chamber 32 can deploy quickly and smoothly.

[0051] 7(A), (B) and 8(A), (B) are plan views showing a part of a manufacturing process of the side airbag device according to the present invention.

[0052] As shown in FIG. 7(A), when folding the airbag 30, first, the inflator 35 is inserted through the opening 40 of the pre-chamber 34, and the inflator 35 is set so that at least the gas discharge hole (not shown) is positioned completely inside the pre-chamber 34.

[0053] The lower folded-back portion 30b is formed by folding the lower portion of the airbag 30, in which the inflator 35 is set, upward along a folding line 102 extending generally in the front-rear direction. The folding line 102 is preferably inclined downward toward the front of the vehicle. In this case, the front portion of the lower portion of the airbag 30 deploys before the rear portion, which has the advantage of being able to quickly restrain the waist of the occupant.

[0054] Next, as shown in Fig. 8(A), the upper end of the airbag 30 is folded downward along a folding line 104 extending generally in the front-rear direction to form an upper folded portion 30a. Note that the folding line 104 is preferably inclined downward toward the front of the vehicle. In this case, the front portion of the upper portion of the airbag 30 deploys slightly later than the rear portion, which has the advantage that the airbag 30 can deploy without interfering with the arms of the occupant.

[0055] As shown in Fig. 8(B), a tether 50 that regulates the deployment behavior of the airbag 30 is provided on the outer surface of the airbag 30. The tether 50 is connected from the state shown in Fig. 8(A). A front end 50a of the tether 50 is connected to the upper folded portion 30a of the airbag 30 by temporary sewing 52, and a rear end 50b is connected to the stud bolt 42.

[0056] The temporary stitching 52 is made weak against pulling forces so as to unravel or break when the airbag 30 is deployed. To make it weak, the thread of the temporary stitching 52 itself is made thin and easy to break, or the stitching is made easy to unravel.

[0057] (Action and effect) In the present invention, the upper end of the airbag 30 is folded downward to form the upper folded portion 30a, one end 50a of the tether 50 is connected to the upper folded portion 30a, and the other end 50b is connected to the inflator 35. In the initial stage of deployment of the airbag 30, as shown in FIG. 5(A), the lower portion of the airbag 30 is inflated and deployed first. Therefore, even if the occupant is in a so-called out-of-position state in which the occupant is seated close to the side support portion of the vehicle seat, it is possible to prevent the upper portion of the airbag 30 from impacting the head or neck of the occupant. In addition, since the lower portion of the airbag 30 is deployed quickly and stably, the deployment behavior of the airbag 30 as a whole is stabilized.

[0058] Thereafter, as the airbag 30 further deploys, the temporary stitching 52 at the front end 50a of the tether 50 is released, and the folded-up portion (30a) of the airbag 30 is released from the folded-up state, and the upper folded-up portion 30a of the airbag 30 deploys upward. As a result, the airbag 30 fully deploys as shown in FIG. 5(B), and a large area can be used to protect the occupant.

[0059] (Variation 1) Fig. 9 is a plan view showing the structure of a side airbag device according to a first modified example of the present invention. In this modified example 1, the configuration of a release part that releases the connection between the front end 150a and the rear end 150b of the tether 150 is different from that in the embodiment of Fig. 8.

[0060] In the first modification, the front end 150a of the tether 150 is connected to the upper folded portion 30a of the airbag 30 not by temporary sewing but by actual sewing 152. A slit 154 extending generally parallel to the width direction of the tether 150 is formed in the middle portion of the tether 150. The tether 150 is configured to break from the slit 154 as the airbag 30 deploys.

[0061] Note that, except for the structure of the release portion (154), the first modification is substantially the same as the embodiment shown in FIG. 8, and the effects and advantages are also the same.

[0062] (Variation 2) Fig. 10(A) is a plan view showing the structure of a side airbag device according to Modification 2 of the present invention. Compared to the embodiment of Fig. 8, Modification 2 differs in the joining method (joining position) of the rear end 250b of the tether 250.

[0063] In the second modification, similarly to the embodiment of FIG. 8, the front end 250a of the tether 250 is connected to the upper folded portion 30a of the airbag 30 by temporary sewing 52. The rear end 250b of the tether 250 is fixed by a circumferential sewing line 254 of the airbag 30. The other configurations and functions and effects are the same as those of the embodiment of FIG. 8.

[0064] (Variation 3) Fig. 10(B) is a plan view showing the structure of a side airbag device according to Modification 3 of the present invention. Compared to the embodiment of Fig. 8, Modification 3 differs in the joining method (joining position) of rear end 350b of tether 350. Also, in relation to Modification 2 described above, the sewing line of rear end 350b of tether 350 is different.

[0065] In the third modification, similarly to the embodiment of FIG. 8, a front end 350a of the tether 350 is connected to the upper folded portion 30a of the airbag 30 by temporary sewing 52. A rear end 350b of the tether 350 is fixed by a circumferential sewing line 354 of the airbag 30. The other configurations and effects are the same as those of the embodiment of FIG. 8.

[0066] (Variation 4) Fig. 11(A) is a plan view showing the structure of a side airbag device according to a fourth modified example of the present invention. In comparison with the embodiment of Fig. 8, this modified example 4 differs in the position of temporary sewing 52 of front end 450a of tether 450. In this modified example 4, front end 450a of tether 450 is set closer to the center in the front-rear direction. As a result, the length of tether 450 is shorter than that of the embodiment of Fig. 8.

[0067] 8, in the fourth modified example, the rear end 450b of the tether 450 is connected to the stud bolt 42. The other configurations and functions and effects are the same as those of the embodiment in FIG.

[0068] (Variation 5) Fig. 11(B) is a plan view showing the structure of a side airbag device according to a fifth modified example of the present invention. In comparison with the embodiment of Fig. 8, this fifth modified example differs in the position of temporary sewing 52 of front end 550a of tether 550. In this fifth modified example, front end 550a of tether 550 is set toward the rear in the front-rear direction. As a result, the length of tether 550 is even shorter than that of the fourth modified example.

[0069] In the fifth modified example, similarly to the embodiment of FIG 8, the rear end 550b of the tether 550 is connected to the stud bolt 42. The other configurations and functions and effects are the same as those of the embodiment of FIG 8.

[0070] Although the present invention has been described in connection with the above exemplary embodiments, many equivalent modifications and variations will be apparent to those skilled in the art from this disclosure. Therefore, the above exemplary embodiments of the present invention are considered to be illustrative and not limiting. Various changes may be made to the described embodiments without departing from the spirit and scope of the present invention. For example, the description of the embodiment of the present invention focuses on near-side side airbags, but the present invention can also be used in far-side airbags (surface of a vehicle seat far from the vehicle door) and single-seat vehicles (vehicles including a portion with only one seat in a row regardless of whether there is a door) in ultra-compact vehicles such as small mobility vehicles.

Claims

1. A side airbag device accommodated in a vehicle seat, an airbag for protecting an occupant seated in the vehicle seat by inflating and deploying toward the front of the vehicle; an inflator fixed to a seat frame inside the vehicle seat and supplying inflation gas to the airbag; A tether connected to an outer surface of the airbag and restricting the deployment behavior of the airbag; The airbag includes a main chamber that is inflated and deployed mainly forward; and a pre-chamber that houses the inflator and is inflated and deployed prior to the main chamber on an inner side of the main chamber in a vehicle width direction, When the airbag is stored, an upper end portion is folded downward to form an upper folded portion, one end of the tether is connected to the vicinity of the upper folded portion, and the other end is connected to the vicinity of the inflator, The tether has a release portion that releases the connection between the one end and the other end when the airbag is deployed, A side airbag device characterized in that the release portion is a temporary stitch for fixing the one end to the airbag, and the temporary stitch is configured to be released or broken as the airbag deploys.

2. A side airbag device accommodated in a vehicle seat, an airbag for protecting an occupant seated in the vehicle seat by inflating and deploying toward the front of the vehicle; an inflator fixed to a seat frame inside the vehicle seat and supplying inflation gas to the airbag; A tether connected to an outer surface of the airbag and restricting the deployment behavior of the airbag; The airbag includes a main chamber that is inflated and deployed mainly forward; and a pre-chamber that houses the inflator and is inflated and deployed prior to the main chamber on an inner side of the main chamber in a vehicle width direction, When the airbag is stored, an upper end portion is folded downward to form an upper folded portion, one end of the tether is connected to the vicinity of the upper folded portion, and the other end is connected to the vicinity of the inflator, The tether has a release portion that releases the connection between the one end and the other end when the airbag is deployed, The side airbag device according to claim 1, wherein the release portion is a slit formed in the middle of the tether, and the tether is configured to break from the slit when the airbag is deployed.

3. A side airbag device as described in claim 1 or 2, characterized in that the upper folded portion of the airbag is formed on the outside in the vehicle width direction.

4. A side airbag device as described in claim 1 or 2, characterized in that the inflator is fixed to the inside of the seat frame by a stud bolt.

5. A side airbag device as described in claim 4, characterized in that the other end of the tether is connected to the stud bolt.

6. A side airbag device as described in claim 1 or 2, characterized in that the other end of the tether is sewn near a sewing line that forms the outer periphery of the chamber of the airbag.

7. A side airbag device as described in claim 1 or 2, characterized in that the one end of the tether is connected to the front of the upper folded portion of the airbag.

8. A side airbag device as described in claim 1 or 2, characterized in that one end of the tether is connected to near the center in the fore-and-aft direction of the upper folded portion of the airbag.

9. A side airbag device as described in claim 1 or 2, characterized in that the one end of the tether is connected rearwardly of the upper folded portion of the airbag.

10. The main chamber is divided into a front chamber portion located at the front side and a rear chamber portion located at the rear side, 3. The side airbag device according to claim 1, wherein the airbag is configured so that air flows from the rear chamber portion to the front chamber portion.

11. A method for manufacturing a side airbag device that has an airbag for protecting an occupant seated in a vehicle seat and is housed in the vehicle seat, comprising: A process for forming the airbag includes connecting a main chamber, which is inflated and deployed mainly forward, and a pre-chamber, which is inflated and deployed prior to the main chamber, on an inner side of the main chamber in the vehicle width direction; inserting an inflator into the pre-chamber to generate inflation gas; forming an upper fold portion by folding an upper end portion of the airbag downward; connecting one end of a tether to the upper folded portion and the other end to a portion adjacent to the inflator; The tether has a release portion that releases the connection between the one end and the other end when the airbag is deployed, a release portion configured to release or break the temporary stitching in association with deployment of the airbag, the release portion being a temporary stitching for fixing the one end to the airbag, the temporary stitching being configured to release or break in association with deployment of the airbag,

12. A method for manufacturing a side airbag device that has an airbag for protecting an occupant seated in a vehicle seat and is housed in the vehicle seat, comprising: A process for forming the airbag includes connecting a main chamber, which is inflated and deployed mainly forward, and a pre-chamber, which is inflated and deployed prior to the main chamber, on an inner side of the main chamber in the vehicle width direction; inserting an inflator into the pre-chamber to generate inflation gas; forming an upper fold portion by folding an upper end portion of the airbag downward; connecting one end of a tether to the upper folded portion and the other end to a portion adjacent to the inflator; The tether has a release portion that releases the connection between the one end and the other end when the airbag is deployed, a release portion that is a slit formed in the middle of the tether, and that is configured so that the tether breaks from the slit as the airbag deploys.

13. A step of fixing the inflator to an inside of a seat frame by a stud bolt; 13. The method for manufacturing a side airbag device according to claim 11, further comprising: a step of connecting the other end of the tether to the stud bolt.

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