Vehicle seat, motor vehicle, and airbag module

A technology is provided effective for aiming at improving workability of an assembling work for assembling an airbag module at a vehicle seat main body side, in a vehicle seat, on which an airbag module is mounted having a construction in which an airbag is developed and expanded from a downside to an upside of a seat cushion against movement of a vehicle occupant in a condition of being seated in a vehicle seat toward a front side of a motor vehicle when accident occurs. The vehicle seat with respect to the present invention has a construction in which an airbag module is housed in a housing portion in a seat pan, and in which a through-hole, into which a harness that transmits an activation signal to a gas generator when accident occurs is inserted, is provided in the housing portion.

FIELD OF INVENTION

The present invention relates to a vehicle seat, and more in detail, to a construction technology for a vehicle seat, on which an airbag module having a construction in which an airbag is developed and expanded from a downside to an upside of a seat cushion against movement of a vehicle occupant toward a front side of the motor vehicle in a seating condition of the vehicle occupant in a vehicle seat when an accident occurs, is mounted.

BACKGROUND OF THE INVENTION

Hitherto, in a seat belt-wearing condition in which a seat belt is worn by a vehicle occupant seated in a vehicle seat, various technologies for blocking occurrence of a phenomenon, i.e., a so-called submarine phenomenon, in which the vehicle occupant has a behavior to slip through a downside of a seat belt along a seat surface, along with a forward movement of a waist portion of the vehicle occupant when an accident occurs, is proposed. For example, in Japanese Unexamined Patent Application Publication No. 5-229378, a vehicle seat having a construction, in which an expanded airbag compresses a seat cushion from below so as to block the movement of the vehicle occupant toward a front side of the motor vehicle at the time when occurrence of the accident, is disclosed. However, in designing such a kind of vehicle seat, there is a demand, for a technology to aim at improving workability of an assembling work for assembling an airbag module at a vehicle main body side.

Accordingly, it is a problem in the present invention to provide a technology effective for aiming at improving workability of the assembling work for assembling the airbag module to the vehicle seat main body side in a vehicle seat on which an airbag module having a construction in which an airbag is developed and expanded from a downside to an upside of a seat cushion against movement of a vehicle occupant in a seating condition in a vehicle seat toward a front side of the motor vehicle when an accident occurs, is mounted.

SUMMARY OF THE INVENTION

To solve the aforementioned problems, the present invention is constructed. Incidentally, the present invention can be applied to a construction technology for a vehicle seat mounted on various kinds of motor vehicles, such as automobile motor vehicles, trucks, buses, electric trains, boats and ships, and so fourth.

The first form of the present invention for solving the aforementioned problems is a vehicle seat mounted on a motor vehicle, and constructed to be provided with at least a left side frame, a right side frame, a bracket, a seat pan, an airbag module, an activation signal transmitting section, and an opening portion.

The left side frame according to the present invention is configured to be a seat frame component extending in a front and back direction at a left side below a seat cushion in a seat frame forming a skeleton of a seat. The right side frame according to the present invention is configured to be a seat frame component extending in the front and back direction at a right side below the seat cushion in the seat frame forming the skeleton of the seat. A bracket according to the present invention is configured to be a seat frame component for connecting the left side frame and the right side frame below the seat cushion in the seat frame forming the skeleton of the seat. The bracket and the left side frame, and the bracket and the right side frame are typically, connected by welding, fastening with a bolt and a nut, or the like. A main body part of the vehicle seat is constructed by the seat frame.

The seat pan according to the present invention is configured to have a construction being disposed below the seat cushion between the left side frame and the right side frame, and above or at a rear side of the bracket adjacent thereto, and including an airbag module housing portion. The “seat pan” according to the present invention is defined as a member constituting a seat bottom surface of the vehicle seat, and specifically, can also be defined as a seat cushion panel, a seat cushion frame, or a seat cushion board, that receives the seat cushion. With regard to a disposition of the seat pan, it is sufficient when entire, or a part of the seat pan is disposed between the left side frame and the right side frame. A construction in which the seat pan is fixed to the left side frame and the right side frame in a manner so as to be hung across by welding, fastening by a bolt and a nut, or the like, or a construction in which the seat pan is fixed to a member situated between the left side frame and the right side frame by welding, fastening of a bolt and a nut, or the like, can be adopted. Further, in the present invention, it is sufficient when the seat pan at least includes a portion being disposed above or at the rear side of the bracket adjacent thereto.

The airbag module according to the present invention is provided with an airbag and a gas generator, and is housed in the airbag module housing portion. In addition, the airbag module is constructed to be set to be such that the airbag is developed and expanded from a downside to an upside of a seat cushion against a forward movement of a vehicle occupant seated in a vehicle seat toward a front side of a motor vehicle when an accident occurs by supplying airbag-expansion gas generated by activation of the gas generator. The airbag module can also be called as an “airbag apparatus” or an “occupant restraint apparatus”.

The activation signal transmitting section according to the present invention is provided with an elongated harness and a to-be-connected portion to which the harness is connected at a gas generator side, and is further provided with a function for transmitting an activation signal to the gas generator when the accident occurs. Accordingly, a signal outputted from a vehicle side in a case that the occurrence of the accidents is detected is transmitted to the elongated harness and the to-be-connected portion at the gas generator side, thereby the gas generator is activated. Incidentally, a connecting operation between the elongated harness and the to-be-connected portion at the gas generator side may previously be performed before an assembling work to assemble the airbag module at the vehicle main body side, or may be performed at the time of the assembling work or after the assembling work. At this moment, with regard to the connecting configuration between the harness and the to-be-connected portion, the connecting configuration may have a detachable construction or an undetachable construction. Further, in the present invention, an entire or a part of the activation signal transmitting section is typically included in the airbag module.

The opening portion according to the present invention is provided at the airbag module housing portion of the seat pan in an opening like shape, and constructed to be a portion that allows the activation signal transmitting section to extend adjacent to the bracket toward outside of the seat pan. An object to be inserted into the opening portion includes each portion of the activation signal transmitting section. The elongated harness and the to-be-connected portion of the harness at the gas generator side is typically configured to be the object to be inserted into the opening portion. With regard to a concrete construction of the opening portion, a construction such as, a through-hole provided at a wall surface of the airbag module housing portion in a penetrated manner, a notched opening provided in a notched manner, a slit, a groove, or the like can appropriately be adopted.

According to a construction as described above, the activation signal transmitting section can easily be inserted into the opening portion along an operation for housing the airbag module in the airbag module housing portion at a work for assembling the airbag module to the vehicle main body side, by providing the opening portion in the airbag module housing portion in which the airbag module is housed. Thereby, the activation signal transmitting section, specifically, the elongated harness is hard to interfere (block) an assembling work thereafter. Further, in a case that the elongated harness is inserted into the opening portion, it is rational because there is no need to pull around the harness, which extends in a lengthy manner between the gas generator in a condition being housed in the airbag module housing portion and a vehicle-side connecting portion, from the airbag module housing portion toward outside thereof. Further, in a case that the to-be-connected portion at the gas generator side is inserted into the opening portion, it is enabled to easily connect the elongated harness to the to-be-connected portion from the outside of the housing portion.

Therefore, in accordance with the invention according to the first form, a vehicle seat capable of being aimed at improving workability of the assembling work for assembling the airbag module to the vehicle seat main body side is provided.

Incidentally, in the present invention, with regard to the opening square measure of the opening portion, it is preferable to make a design therefor which is suppressed as much as possible within a limit not to interfere a smooth inserting work for the activation signal transmitting section. According to such a construction described above, the airbag-expansion gas generated by the activation of the gas generator is enabled to be suppressed to be leaked from a space partitioned by the airbag module housing portion and the airbag cover that covers the housing portion toward an outside of the space, as much as possible.

The second form of the present invention for solving the aforementioned problems is the vehicle seat having the opening portion according to the first form constructed as a through-hole provided in a manner so as to be penetrated through an attaching wall surface of the airbag module housing portion where the airbag module is attached in a housed condition in which the airbag module is housed in the airbag module housing portion.

According to such a construction as described above, in the housed condition of the airbag module, a distance between the airbag module and the through-hole can be suppressed, and it is enabled to perform a rational disposition of the activation signal transmitting section at the airbag module housing portion.

The third form of the present invention for solving the aforementioned problems is the vehicle seat provided with a retainer for housing the gas generator in the airbag module, a together-fastening member for fastening the seat pan and the bracket together and fixing the same, in either one of the first or second forms. Typically, by use of the together-fastening member, such as fastening with the bolt and nut, rivet, and so forth, it becomes enabled to perform a together fastening and fixing operation. Further, the opening portion is provided at the wall surface of each of the retainer, the seat pan, and the bracket being in close contact with each other by the together-fastening member. Since the board thicknesses of portions to be in close contact with each other is suppressed, a length with regard to a penetrating direction (conformed to a board thickness direction) of the through-hole can be suppressed and it is enabled to easily perform the inserting work for the activation signal transmitting section for inserting the same into the through-hole.

The fourth form of the present invention for solving the aforementioned problems is a motor vehicle that at least includes a vehicle seat and a seat belt for restraining the vehicle occupant seated in the vehicle seat according to any one of the first through third forms. Further, the motor vehicle has a construction, in which in a seat belt-wearing condition in which the seat belt is worn by the vehicle occupant seated in the vehicle seat, occurrence of a movement of the vehicle occupant to slip through a downside of a seat belt along a seat surface, associated with a forward movement of a waist portion of the vehicle occupant when the accident occurs, i.e., a so-called submarine phenomenon, is blocked by the airbag module mounted on the vehicle seat.

Therefore, in accordance with the invention according to the fourth form, a motor vehicle capable of being aimed at improving the workability of the assembling work for assembling the airbag module at the vehicle seat main body side is provided.

The fifth form of the present invention for solving the aforementioned problems is an airbag module having the construction substantially similar to the airbag module serving as a component of the vehicle seat according to the first form.

Therefore, in accordance with the invention according to the fifth form, an airbag module capable of being aimed at improving the workability of the assembling work for assembling the airbag module at the vehicle seat main body side is provided.

As described above, according to the present invention, in the vehicle seat on which an airbag module having the construction in which the airbag is developed and expanded from the downside to the upside of the seat cushion against the movement of the vehicle occupant in the forward direction of the motor vehicle in the seat condition in the vehicle seat when the accident occurs, it becomes capable of aiming at improving the workability of the assembling work for assembling the airbag module to the vehicle seat main body side by providing an opening portion, into which the activation signal transmitting section is inserted for transmitting an activation signal to the gas generator when the accident occurs, specifically, in the airbag module housing portion for housing the airbag module.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinbelow, an embodiment of the present invention will be explained in detail referring to the drawings. Firstly, a construction of a vehicle seat100as an embodiment of a “vehicle seat” with respect to the present invention will be explained referring toFIGS. 1 through 3. At this moment,FIG. 1is a view showing an internal structure of the vehicle seat100according to the present embodiment, and is a perspective view looking from diagonal backside of the motor vehicle.FIG. 2is a cross-section at a line A-A inFIG. 1.FIG. 3is a cross-section at a line B-B inFIG. 1.

As shown inFIG. 1, the vehicle seat100according to the present embodiment is a vehicle seat to be mounted on a motor vehicle, and is mainly constructed of a seat frame10, a seat pan20, and an airbag module30. The vehicle seat100is constructed to serve as a driver's seat where a driver is seated, or a passenger seat. Further, in the motor vehicle on which the vehicle seat100is mounted, a seatbelt (corresponds to a “seatbelt” in the present invention) to be worn by an occupant seated in the vehicle seat100is further mounted. Incidentally, a direction indicated by “FR” inFIG. 1represents a front side of the motor vehicle, and that indicated by “UP” represents an upside of the motor vehicle.

The seat frame10is constructed to serve as a frame that forms a skeleton portion of the vehicle seat100, and is at least provided with a base frame12and a back frame14. The seat frame10corresponds to a “seat frame” in the present invention. On the base frame12, a seat cushion (not shown) formed from a material having plasticity, such as a urethane material, or the like, is mounted, and the seat cushion constitutes a seat surface of the vehicle seat100. Further, on the back frame14, a seat back (not shown) formed from a material having plasticity, such as a urethane material, or the like, is mounted, and the seat back constitutes a back surface of the vehicle seat100. Furthermore, an outer surface of each of the seat cushion and the back seat is covered with scurf skin (not shown) formed from leather, cloth, or the like.

The base frame12is a frame to be disposed below the seat cushion, and is provided with a left-and-right pair of side frames,12aand12b(a left side frame12a, and a right side frame12b), extending in a front and back direction of the vehicle seat100(conforming to a front and back direction of the motor vehicle). The left side frame12amentioned here corresponds to a “left side frame” in the present invention, and the right side frame12bcorresponds to a “right side frame” in the present invention.

Further, at an upper portion side of the base frame12, a bracket13for reinforcement is provided so as to hang across the left and right side frames,12aand12b. The bracket13is constructed to be a plate shape (a curved plate shape inFIG. 1) having a predetermined board thickness, and is connected to the left and right side frames,12aand12b, by means of a welding process, a fastening process with a bolt and a nut, or the like. This bracket13serves as a supporting member for supporting the seat pan20, and is constructed to serve as a holding member for connecting and holding the left and right side frames,12aand12b. In addition, the bracket13also serves as a positioning member when joining the left and right side frames,12aand12b, resulting in providing a good assembling capability. This bracket13corresponds to a “bracket” in the present invention.

The back frame14is a frame that is rotatably connected to the base frame12via a supporting shaft15and a reclining device (not shown). At an upper part of the back frame14, a head rest16is attached to a position corresponding to a head portion of a vehicle occupant.

The seat pan20is provided so as to hang across the left-and-right pair of the side frames,12aand12bin a manner so as to cover the same from above, at a portion above the bracket13and below the seat cushion, and so as to be adjacent to the bracket above or at a rear side of the bracket. The seat pan20is a member constituting a seat bottom surface of the vehicle seat100, and specifically, can also be defined as a seat cushion panel that receives the seat cushion, a seat cushion frame, or a seat cushion board. Although described later in detail, the seat pan20is attached to the bracket13by means of the fastening process with the bolt and nut at two places. The seat pan20can also be joined to the left and right side frames,12aand12b, by means of the welding process or the fastening process with the bolt and nut. The seat pan20has a function to receive a load from the seat cushion. The seat pan20corresponds to a “seat pan” in the present invention. The seat pan20at least includes a portion being disposed above or at the rear side of the bracket adjacent thereto in the present invention.

Further, in the seat pan20, a housing portion21for housing the airbag module30is provided. The housing portion21corresponds to an “airbag module housing portion” in the present invention. In the present embodiment, the housing portion21is constructed to have a hollow portion23(sometimes called as “concave portion”, “cavity portion”, or “concave area”) that is downwardly hollowed. The hollow portion23is configured to be a portion where the airbag module30can be held by the hollow portion23.

As shown inFIG. 2, the housing portion21is provided with a first extension portion20aconstituting a bottom surface of the hollow portion23, and a second extension portion20bextending to a rear side (right side inFIG. 2) in relation to the first extension portion20a. A step portion (step shape) is formed by means of a difference of elevation in an upper and lower direction between the first extension portion20aand the second extension portion20b. In concrete terms, the construction is made such that the first extension portion20ais extending at a portion lower than the second extension portion20b. Further, the housing portion21is opened diagonally upward toward the backside. Accordingly, a developing direction (sometimes called “protruding direction”) of an airbag (airbag31described later) of the airbag module30is configured to be a diagonally upward and backward direction, as a direction indicated by an arrow40inFIG. 2. Although described later in detail, according to a present construction, a work for housing the airbag module30in the housing portion21, and a work for attaching and fixing the airbag module30to a seat pan20side is aimed at facilitating by means of a holding function (or a positioning function) of the airbag module30provided by the hollow portion23that is caved downward.

Further, according to the present construction, when the airbag module30is held at a proper position in the hollow portion23, the airbag module30in the held condition is configured to be positioned at a front side in relation to the step portion between the first extension portion20aand the second extension portion20b. Accordingly, a protrusion of the airbag module30toward a second extension portion20bside can be discriminated on the basis of a result of a visible confirmation between a first condition in which the airbag module30held by the hollow portion23covers the step portion and a second condition in which the covering operation is released. That is, a case, in which an entire step portion or a part of the step portion cannot be visibly confirmed, represents the first condition in which the airbag module30covers the step portion, and this results in that a rear end surface of the airbag module30is discriminated to be protruded out to the second extension portion20bside across the step portion. At this moment, the airbag module30can be judged not to be located at a proper position. On the other hand, a case, in which the entire step portion can be visibly confirmed, represents the second condition in which the airbag module30does not cover the step portion, and this results in that the rear end surface of the airbag module30is discriminated not to be protruded out to the second extension portion20bside across the step portion. At this moment, the airbag module30can be judged to be located at the proper position. By discriminating the protrusion of the airbag module30toward the second extension portion20bside, it becomes to be enabled to prevent the airbag module30from being pinched by an airbag cover (not shown) that covers the housing portion21. With regard to visibility of the step portion, the visibility of the step portion can be aimed at being further improved by forming a colored line at the step portion.

Incidentally, the housing portion21of the seat pan20in the present embodiment has a construction including a hollow portion23that is caved downward. Therefore, the airbag module30in the housed condition (non-operating time) is aimed at being protected. Further, an airbag cover (not shown) that covers the housing portion21in a condition, in which the airbag module30is housed therein, is mounted on the seat pan20, and protection for the airbag module30in the condition being housed by the airbag cover is aimed at being further improved.

As shown inFIGS. 2 and 3, the airbag module30at least includes an airbag31, a gas generator (sometimes called as, inflator)32, a retainer33, and a harness37. The airbag module30corresponds to an “airbag module” in the present invention.

The airbag31is constructed as an airbag element that is folded back in a predetermined folding configuration and housed, and that is developed and expanded by airbag-expansion gas generated by the activation of the gas generator32and supplied to the airbag element when an accident occurs. In concrete terms, the airbag31is developed and expanded from a downside to an upside of a seat cushion against movement of a vehicle occupant toward a front side of the motor vehicle in a seating condition of the vehicle occupant in a vehicle seat when the accident occurs. Thereby, in a seatbelt-wearing condition in which a seatbelt is worn by a vehicle occupant seated in a vehicle seat100, a phenomenon, i.e., a so-called submarine phenomenon, in which the vehicle occupant has a behavior to slip through a downside of a seatbelt along a seat surface, along with a frontward movement of a waist portion of the vehicle occupant when the accident occurs, is blocked or suppressed. The airbag31mentioned here corresponds to an “airbag” in the present invention, and the gas generator32corresponds to a “gas generator” in the present invention.

The retainer33is constructed to serve as a member for housing the gas generator32. The retainer33corresponds to a “retainer” in the present invention. A fixing bolt34for attaching and fixing the airbag module30to the base frame12side is provided in the retainer33. The airbag module30is attached and fixed to the base frame12side by means of the fixing bolt34. In concrete terms, the fixing bolt34is configured to be able to be inserted into a through-hole22penetrating through the seat pan20, the bracket13and the airbag31in a condition in which the airbag module30is housed in the housing portion21of the seat pan20. Accordingly, three members of the retainer33, the seat pan20, and the bracket13are integrally formed by being fixed to each other by being fastened together (sometimes called as “fixing by together-fastening”) by fastening (screwing) the fixing bolt34penetrated through the through-hole22, and the nut36with each other. In this case, the nut36may be constructed as a separate body from the bracket13, or may have a construction in which the nut36is integrally jointed with the bracket13. Further, a shape of a round hole, a long hole, a slit, or the like can appropriately be selected as the through-hole22. The fixing bolt34and the nut36mentioned here correspond to a “together-fastening member” in the present invention.

Incidentally, the present embodiment is constructed such that an extending direction of a bolt axis of the fixing bolt34is approximately conformed to a developing direction of the airbag31along a direction indicated by an arrow40inFIG. 2. According to such a construction, it is enabled that fastening force of the fixing bolt34is effectively used as force against an airbag load when the airbag is developed and expanded.

The harness37is constructed as a harness for transmitting an activation signal (sometimes called as a “control signal”) to the gas generator32when the accident occurs. In concrete terms, as shown inFIG. 3, the harness37is extended in an elongated manner from a gas-generator-side connector portion32aof the gas generator32up to a vehicle-side connector portion38passing through a through-hole25. The harness37is extended between the gas generator32and the vehicle-side connecting portion39by means of that the vehicle-side connector portion38is connected to the vehicle-side connecting portion39. The harness37corresponds to an “elongated harness” in the present invention. Further, the gas-generator-side connector portion32ais a to-be-connected portion to which the harness is connected at the gas generator32side, and corresponds to a “to-be-connected portion” in the present invention. Further, an “activation signal transmitting section” in the present invention is constructed by the harness37and the gas-generator-side connector portion32a.

The through-hole25is an opening portion for penetrating the retainer33, the airbag31, the seat pan20, and the bracket13, and is constructed so as for the harness37to be inserted at a time of assembling work for the airbag module30to the vehicle seat main body. Further, the through-hole25is constructed as a portion allowing the harness37to be expanded toward outside of the seat pan20while being in close contact with the bracket13. The through-hole25corresponds to an “opening portion” in the present invention. Furthermore, the through-hole25is provided in an opening shape in the housing portion21in each portion in the seat pan20, and in concrete terms, in the attaching wall surface to which the airbag31is attached. In such a construction as described above, a distance between the airbag31and the through-hole25can be suppressed and it becomes capable of performing a rational disposition of the housing portion21and the harness37.

Further, in the present embodiment, as described above, the through-hole25is provided at a wall surface of each of the retainer33, the seat pan20, and the bracket13being in close contact with each other by the together fastening operation by the fixing bolt34and the nut36. In such a construction as described above, since the board thickness of the portions being in close contact with each other is suppressed, the length with regard to the penetrating direction (conformed to the board thickness direction) of the through-hole25can be suppressed, and an inserting work for inserting the harness37into the through-hole25can easily be performed.

Incidentally, in the present embodiment, it is preferable for the through-hole25to make a design for an opening square measure to be suppressed as much as possible within a limit not to interfere a smooth inserting work for the vehicle-side connector portion38and the harness37. According to such a construction described above, the airbag-expansion gas generated by the activation of the gas generator32is enabled to be suppressed to be leaked from a space partitioned by the housing portion21and the airbag cover (not shown) that covers the housing portion21toward an outside of the space, as much as possible.

Further, in the present embodiment, it is preferable to make a design in which a sealing member (sometimes called as a “grommet for harness”) formed from a rubber material or a resin material is intervened in a close contacting manner between the through-hole25and the harness37inserted into the through-hole25. According to such a construction as described above, in addition to that the harness37can stably be held in the through-hole25, a waterproof effect can be realized with regard to water intruding into the housing portion21through the through-hole25or other portion, and it is effective for the airbag module30housed in the housing portion21, and specifically, for the airbag31to be prevented from getting wet by moisture or water.

A work for housing the airbag module30in the present embodiment, specifically, a work for housing the airbag module30in the housing portion21of the seat pan20, and a work for attaching and fixing the airbag module30to the seat pan20side will be explained referring toFIGS. 4 through 7.

FIG. 4is a perspective view schematically showing a work for housing the airbag module30in the housing portion21of the seat pan20. As shown inFIG. 4, in the housing work for the airbag module30, firstly, the airbag module30is moved to the housing portion21in a manner for the fixing bolt34at the airbag module30side to be headed toward the housing portion21of the seat pan20. Further, the harness37is inserted into the through-hole25of the housing portion21from a vehicle-side connector portion38side, i.e., a tip end of the harness37. In the present embodiment, since the construction is formed such that the housing portion21is provided with the through-hole25, the harness37can be inserted into the through-hole25along an operation for housing the airbag module30in the housing portion21, and the elongated harness37is hard to interfere (block) the assembling work thereafter. Accordingly, it is enabled to be aimed at facilitating the assembling work for the airbag module30.

Further, since there is no need to pull around the harness37extending in an elongated manner between the gas generator32in a condition of being housed in the housing portion21and the vehicle side connecting portion39, from the housing portion21to the outside of the housing portion21, it is rational.

Continuously, with regard to the work until the airbag module30is attached and fixed to the seat pan20side, the same can be performed by at least using, for example, three steps shown inFIG. 5throughFIG. 7. At this moment, any ofFIG. 5throughFIG. 7is a cross-section showing a process for attaching and fixing the airbag module30to the housing portion21of the seat pan20.

As shown inFIG. 5, in the first step, the airbag module30is inserted toward the hollow portion23(the first extension portion20a) from above the seat pan20, in a condition of being headed so as for a gas generator32side to be situated at a downside. At this time, the airbag module30can be easily introduced into the hollow portion23along a concaved shape of the hollow portion23. Thereby, a provisionally held condition of the airbag module30shown inFIG. 6is formed. At this moment, the bolt axis of the fixing bolt34is extended approximately in a left-and-right direction.

Next, as shown inFIG. 6, in the second step, the airbag module30is rotated in a direction indicated by an arrow41inFIG. 6around the step portion as a pivot fulcrum, in a condition in which a module lower portion35of the airbag module30in a provisionally held condition is in contact with the step portion between the first extension portion20aand the second extension portion20b. Further, the fixing bole34is caused to be in close contact with the through-hole22by the rotation. Thereby, an inserting condition where the fixing bolt34is inserted into the through-hole22is formed, as shown inFIG. 7. In consideration of ease of insertion for the fixing bolt34, it is preferable to use an elongate hole extending in an upper and lower direction, as the through-hole22.

At the last, as shown inFIG. 7, in the third step, by fastening the fixing bolt34and the nut36with each other, an integrally formed condition (the condition shown inFIG. 2) where the retainer33, the seat pan20, and the bracket13are fastened and fixed to each other, is formed. At this moment, the airbag module30, the seat pan20and the bracket13are fastened together and fixed by the fixing bolt34, whereby pressure caused at the time when the airbag31is developed and expanded when the accident occurs, namely a load generated when the airbag module30is operated is to be received by the seat pan20and the bracket13that are integrally formed by being fastened and fixed together.

At this moment, since strength of the seat pan20can be raised by means of that a board thickness of the bracket13that is fastened and fixed together to the seat pan20is added to a board thickness of the seat pan20, it is enabled that the strength required for the vehicle seat100is secured, upon suppressing the board thickness of the seat pan20in this extent. That is, the strength of the vehicle seat100can be secured while aiming at weight saving for the vehicle seat100by means of a cooperative work among the retainer33, the seat pan20, and the bracket13. Incidentally, in a case that a specification, in which the board thickness of the seat pan20is suppressed, is considered, with regard to a board thickness, d1, of the seat pan20, and a board thickness, d2, of the bracket13, it is preferable to set the same on the basis of a relationship expressed by an inequality, d1≦d2.

Further, occurrence of an abnormal noise due to contact or the like of the seat pan20and the bracket13can be prevented by fastening and fixing together, and seating comfortableness of the vehicle seat100can be improved by raising the strength of the seat pan20.

Furthermore, since the seat pan20is constructed to be fixed to the bracket13by together fastening and fixing, and the seat pan20is not required to be fixed to the left side frame12aand the right side frame12bby welding or the like, a manufacturing process of the vehicle seat100can be simplified.

By performing the aforementioned first to the third steps in the order, the work for attaching and fixing the airbag module30to the seat pan20side is facilitated. Specifically, in the second and third steps, the module lower portion35of the airbag module30held by the hollow portion23is caused to come into contact with the step portion between the first extension portion20aand the second extension portion20bfrom beginning to end during the time until the airbag module30is fastened to the seat pan20side by means of the fixing bolt34. Since the airbag module30is thereby positioned, it is enabled to aim at improving an assembling capability of the airbag module30.

Incidentally, the present invention is not limited to the aforementioned embodiment, and various applications and modifications are considered. For example, the following each embodiment, to which the aforementioned embodiment is applied, can be performed.

The construction of the seat pan20and the airbag module30in the aforementioned embodiment can appropriately be changed as needed. For example, each embodiment shown inFIG. 8throughFIG. 12can also be adopted.

FIG. 8is a perspective view showing a construction of a seat pan120and an airbag module130according to another embodiment,FIG. 9is a cross-section along a line C-C, inFIG. 8, andFIG. 10is a cross-section along a line D-D, inFIG. 8.

Although the seat pan120in the embodiment shown inFIG. 8is provided with a housing portion21similar to the seat pan20, the seat pan120is constructed to be further provided with a left-and-right pair of housing portions,24and24. On the other hand, as shown inFIG. 9, in the airbag module130housed in the housing portion21, a left-and-right pair of brackets33afor bolts34, is provided in a retainer33. Each bracket33afor bolt34is fastened to the seat pan120and a bracket13together and fixed thereto with a fixing bolt34and a nut36in a condition of being housed in each of the housing portions,24and24. In the airbag module130, the developing direction of an airbag31developing and extending at the time when the accident occurs is configured to be diagonally upward toward the rear side as indicated by a direction of an arrow40inFIG. 9, similar to the case of the airbag module30.

At this moment,FIG. 11is a perspective view schematically showing a work for housing the airbag module130according to another embodiment in the housing portion21of the seat pan120. As shown inFIG. 11, in the housing work for the airbag module130, firstly, the airbag module130is moved to the housing portion21in a manner so as for the fixing bolt34at the airbag module130side to be headed to the housing portion24of the seat pan120. Further, a harness37is inserted into the through-hole25of the housing portion21from a vehicle-side connector portion38side, i.e., the tip end of the harness37. In the present embodiment, since the construction is formed such that the through-hole25is provided in the housing portion21, the harness37can be inserted into the through-hole25along the operation for housing the airbag module130in the housing portion21, and the elongated harness37hard to interfere the assembling work thereafter. Further, it is enabled to be aimed at facilitating the assembling work for the airbag module130. Furthermore, a condition in which the retainer33, the seat pan120, and the bracket13are fastened together and fixed to each other is formed by fastening the fixing bolt34and the nut36to each other after the fixing bolt34is inserted into a through-hole22penetrating the seat pan120and the bracket13.

Moreover, in the aforementioned embodiment, although a case that the through-hole25to which the harness37is inserted is provided in the housing portion of the seat pan, is described, in the present invention, a construction in which an opening for inserting a member other than the harness37is provided in the housing portion of the seat pan can also be adopted. With regard to the construction, explanation is made referring toFIG. 12.FIG. 12is a perspective view schematically showing the work for housing an airbag module230according to another embodiment in a housing portion21of a seat pan220.

The airbag module230, shown inFIG. 12has a construction in which a gas-generator-side connector portion32aof a gas generator32is exposed to an outer surface of the airbag module230passing through a penetrating portion of an airbag31, in addition to a construction similar to the airbag module30. On the other hand, in this embodiment, a through-hole26(sometimes called as a “notched hole”) serving as an opening portion penetrating through the seat pan220and a bracket13is provided at a corner portion of the housing portion21of the seat pan220. This embodiment is constructed such that a gas-generator-side connector portion32ais inserted into the through-hole26at the time of assembling work for assembling the airbag module230with the vehicle main body. Further, the through-hole26is constructed to be a portion allowing the gas-generator-side connector portion32ato be expanded toward outside of the seat pan220while being in close contact with the bracket13. The through-hole26corresponds to an “opening portion” in the present invention.

In such a construction described above, when the airbag module230is housed in the housing portion21of the seat pan220, the gas-generator-side connector portion32ais exposed to a wall surface (rear surface) at an opposite side of a housing wall surface of the housing portion21through the through-hole26. Accordingly, it is enabled for a connector37aof a harness37to be easily connected to the gas-generator-side connector portion32afrom an outside of the seat pan220. Although not shown in the drawings, a holding member (for example, a clip or the like) for holding the harness37at side frames,12aand12b, can also be provided as needed.

Incidentally, in the present embodiment, it is preferable for the through-hole26to make a design for an opening square measure to be suppressed as much as possible within a limit not to interfere a smooth inserting work for a vehicle-side connector portion38and the harness37. According to such a construction described above, the airbag-expansion gas generated by the activation of the gas generator32is enabled to be suppressed to be leaked from a space partitioned by the housing portion21and the airbag cover (illustration is omitted) that covers the housing portion21toward an outside of the space, as much as possible.

Further, in the aforementioned embodiment, although a case that the through-holes,25and26, provided in a penetrating manner at a wall surface of the housing portion21of the seat pan is used as an opening portion is described, in the present invention, the structure of the opening portion is not limited to a configuration of a through hole, but other opening configurations, such as for example, a notched opening provided in a notched manner, a slit, a groove, or the like can be adopted.

Moreover, in the aforementioned embodiment, although a construction of the vehicle seat100that is constructed as a driver's seat in which a driver is seated, or a passenger seat is explained, the characteristic part of the present invention can also be applied to a construction of various types of vehicle seats including the driver's seat or a passenger seat, for example, a rear seat. In the motor vehicle in this case, various types of motor vehicles moving with vehicle occupants taken on, such as automobiles, airplanes, boats and ships, electric trains, buses, trucks, and so forth are included.