Driver's seat air bag device and manufacturing method for same

Abstract

The present invention achieves a driver's seat air bag device that does not require an emblem plate when forming an emblem on a cover of the driver's seat air bag device.　The driver's seat air bag device comprises: a cover 20 for covering an air bag module mounted in a steering wheel; and a groove portion 30c provided in a front surface portion 21 of the cover 20 and forming an emblem. The front surface portion 21 is provided with a coating portion 40 obtained by coating a region inside the groove portion 30c. The groove portion 30c includes a bottom surface 31c and a side surface 32c that extends in a direction intersecting the bottom surface 31c. The coating portion 40 comprises a primer layer 41 provided so as to cover at least the bottom surface 31c, and a coating material layer 42 provided so as to cover the primer layer 41.

Description

Driver's Seat Airbag Device and Method of Manufacturing the Same

[0001] The present invention relates to a driver's seat airbag device mounted on a steering wheel of a vehicle and restraining an occupant in the event of a vehicle collision, and a method of manufacturing the same.

[0002] In particular, the present invention relates to a structure of a cover formed with an emblem attached so as to cover an airbag module, and a method of manufacturing the cover formed with the emblem.

[0003] Generally, a driver's seat airbag device is standard equipment on the steering wheel of a vehicle.

[0004] The driver's seat airbag device is mounted inside the steering wheel and has a structure covered with a cover. Since the surface part of this cover is in a visually prominent position approximately at the center of the steering wheel, an emblem generally composed of a company logo of an automobile manufacturer, characters, figures, symbols, etc. representing a specific vehicle name is attached.

[0005] The emblem is required to have a stylish design. Therefore, conventionally, for example, a decoration including an emblem is formed in advance on a plate made of metal or resin by surface treatment such as painting or plating, and a method of attaching a decorated plate to the cover of the driver's seat airbag device by adhesion or welding is often adopted.

[0006] For example, Patent Document 1 discloses a thermoplastic resin plate (decorative part) that is attached to a mounting recess in the cover of a driver's seat airbag device. Multiple through holes are formed through the mounting recess near the center and periphery. A decorative layer made of metal plating is formed on the surface of the plate, and an emblem is formed in this decorative layer. In addition, multiple mounting legs are formed protruding from the back surface of the plate near the center and periphery, which can be inserted into the through holes formed in the mounting recess of the cover. When the tips of the mounting legs are thermally deformed with each mounting leg inserted into the respective through holes of the cover, a bridge portion is connected between the tips of each mounting leg, or a head is formed independently at the tip of each mounting leg. As a result, the plate with the emblem is fastened to the mounting recess of the cover.

[0007] Japanese Patent Publication No. 2001-162997

[0008] The conventional cover structure and manufacturing method described above have drawbacks: it is time-consuming to create a decorative layer including the emblem on the plate, and it is also time-consuming to attach the plate with the decorative layer already formed (hereinafter referred to as the emblem plate) to the cover.

[0009] The inventors of this application have diligently studied a novel configuration in which, instead of attaching an emblem plate, a groove corresponding to the shape of the emblem is provided in the cover, and a painted portion is provided in this groove. This method not only streamlines the manufacturing process of the cover, but also provides an emblem with a new feel that differs from conventional emblem plates, and increases the range of emblem options.

[0010] On the other hand, in the novel configuration of the present invention, the paint layer in the grooved portion must have sufficient strength to prevent it from easily peeling off over time. Furthermore, if it becomes necessary to apply a base coat to the entire cover before applying the paint layer to the groove, it will lead to increased costs and longer working times. In the novel configuration of the present invention, it is required that painting the entire cover be unnecessary.

[0011] This invention has been made in view of these circumstances, and aims to realize a driver's side airbag system that does not require an emblem plate when forming an emblem on the cover of the driver's side airbag system.

[0012] The driver's seat airbag device of the present invention comprises a cover that covers an airbag module mounted on the steering wheel, and a groove provided on the surface of the cover that forms an emblem, wherein a painted portion is provided in the area inside the groove.

[0013] In this specification, the term "cover" is used to include all things commonly referred to as "airbag cover," "pad," "cover body," etc.

[0014] Furthermore, in this specification, the term "emblem" is used to include all things that are generally referred to as "marks," "trademarks," "symbols," or "ornaments."

[0015] The grooves on the surface are recessed areas that are lower than the cover surface. The painted areas inside the grooves can use paint of a different color than the cover surface outside the grooves. This makes the emblem formed by the grooves visually more prominent.

[0016] In the present invention, the groove portion comprises a bottom surface and a side surface extending in a direction intersecting the bottom surface, and the painted portion may consist of a primer layer provided so as to cover at least the bottom surface and a paint layer provided so as to cover the primer layer.

[0017] The primer layer refers to a layer formed to cover the bottom surface of a groove, for example, by discharging primer into the groove from the nozzle of a painting device. Primer is an undercoat used to improve the adhesion and corrosion resistance of paint to the substrate.

[0018] The paint layer refers to a layer formed to cover the primer layer, for example, by discharging paint from a nozzle of a painting device into the inside of the groove after the primer layer has been formed. In the above configuration, the adhesion strength of the paint layer is increased by the formation of the primer layer, and the paint layer bonds more firmly to the groove of the cover.

[0019] In this invention, when the cover is installed so that the plane connecting one end and the other end of the surface is horizontal, the bottom surfaces of the multiple grooves may be arranged to extend horizontally. This configuration can be applied when the painted portion consists of a primer layer and a paint layer, as well as when the painted portion consists of only a paint layer.

[0020] By configuring the bottom surfaces of multiple grooves to extend horizontally, the thickness of the primer layer formed by the primer discharge is made uniform in each groove. This ensures that the effect of the primer layer is evenly distributed across the entire bottom surface of the grooves, making it possible to more reliably increase the adhesion strength of the paint layer.

[0021] In this invention, the surface of the cover is coated only in the area inside the groove, and the area outside the groove may be left uncoated.

[0022] "Paint-free" means that no painting is done, including primer painting, base coating, or paint painting. In other words, the surface of the cover, excluding the grooves, is left as is, with the surface of the resin composition that makes up the cover exposed.

[0023] In the above configuration, if a painted area consisting of a primer layer and a paint layer is provided only in the groove, it becomes unnecessary to apply primer to the entire cover, and thus unnecessary to apply a base coat.

[0024] The present invention relates to a method for manufacturing a driver's seat airbag device, which includes, when manufacturing a cover that covers an airbag module mounted on a steering wheel, a first step of providing a groove for forming an emblem on the surface of the cover, and a second step of providing a painted area by applying paint to the area inside the groove using a painting apparatus equipped with a dispenser.

[0025] In the above manufacturing method, the first step may include a step of providing a groove having a bottom surface and a side surface extending in a direction intersecting the bottom surface, and the second step may include a primer layer forming step of providing a primer layer so as to cover at least the bottom surface, and a paint layer forming step of providing a paint layer so as to cover the primer layer.

[0026] In the above manufacturing method, the first step may include a step of providing each bottom surface such that when the cover is installed so that the plane connecting one end and the other end of the surface is horizontal, each bottom surface of the multiple grooves extends in the horizontal direction.

[0027] In the driver's seat airbag device of the present invention, the cover that covers the airbag module mounted on the steering wheel has grooves on its surface for forming an emblem, and the surface of the cover is provided with painted areas in the region inside the grooves.

[0028] According to this invention, since no emblem plate is used, the manufacturing process for the cover can be made more efficient. Furthermore, it is possible to provide an emblem with a new feel that differs from conventional emblem plates.

[0029] Furthermore, if the groove portion comprises a bottom surface and side surfaces extending in a direction intersecting the bottom surface, and the painted portion is configured to consist of a primer layer provided to cover at least the bottom surface and a paint layer provided to cover the primer layer, the adhesion strength of the paint layer will be increased, and the paint layer will bond more firmly to the groove portion of the cover.

[0030] Furthermore, by configuring the bottom surfaces of multiple grooves to extend horizontally, the thickness of the primer layer formed by the primer discharge is made uniform in each groove. This ensures that the effect of the primer layer is evenly distributed across the entire bottom surface of the grooves, thereby more reliably increasing the adhesion strength of the paint layer.

[0031] Figure 1 is a view from the driver's side of a steering wheel equipped with a driver's side airbag device according to an embodiment. Figure 2 is a schematic cross-sectional view taken along line A-A in Figure 1, showing the configuration of the driver's side airbag device. Figure 3 is a plan view of the cover of the driver's side airbag device according to the embodiment. Figure 4 is a schematic diagram showing an example of the configuration of a dispenser in a painting apparatus used in the manufacturing method of the driver's side airbag device according to the embodiment. Figure 5 shows the process of dispensing paint from a jetting head into grooves constituting an emblem for painting. Figure 6 is a schematic cross-sectional view taken along line B-B in Figure 3, illustrating a method for providing a painted portion consisting of a primer layer and a paint layer in the grooves. Figure 7 is a schematic cross-sectional view taken along line C-C in Figure 3, showing the state of each bottom surface of the grooves. Figure 8 is a diagram similar to Figure 7, showing the state of each bottom surface of the grooves in a modified example. (a) shows that in some grooves of the embodiment, the thickness of the primer layer may not be uniformly formed, and (b) shows that in the modified example, the thickness of the primer layer is uniformly formed in all grooves. Figure 10 is a block diagram showing an example of a method for manufacturing the driver's seat airbag device according to this embodiment.

[0032] Embodiments of the present invention will be described in detail below with reference to the drawings. Note that the following embodiments are examples of the present invention and are not intended to limit the scope of the present invention, its applications, or its uses.

[0033] This embodiment relates to a driver's seat airbag system 10, which is mounted inside the steering wheel 1 and inflates and deploys an airbag cushion 12 towards the rear of the vehicle towards the occupant seated in the driver's seat during a vehicle collision, thereby restraining and protecting the occupant's upper body, including their head. This embodiment particularly relates to the structure of the airbag module 11 and the cover 20 that covers the boss portion 3 which constitutes the central part of the steering wheel 1.

[0034] The driver's side airbag system 10 includes a cover 20 that covers the top of the airbag module 11 in a dome shape. The airbag module 11 includes an airbag cushion 12 that is stored in a rolled or folded state, and an inflator 13 that ejects gas to inflate the airbag cushion 12.

[0035] The steering wheel 1 is mounted on a steering shaft 8 that is installed in the vehicle in an inclined position.

[0036] In this specification, unless otherwise specified, the "up" and "down" directions are defined as the vertical direction along the axial direction of the steering shaft 8 to which the steering wheel 1 is assembled, with the cover 20 side being "up" and the boss portion 3 side being "down". Although the steering wheel 1 rotates, the front-rear direction is defined based on the position when driving straight, with the front of the vehicle (facing the windshield) in the direction perpendicular to the axis of the steering shaft 8 being "front" and the rear of the vehicle (facing the occupant seated in the driver's seat) being "rear". Similarly, the left-right direction is defined based on the position of the steering wheel 1 when driving straight, with the left side of the vehicle in the direction perpendicular to the axis of the steering shaft 8 being "left" and the right side of the vehicle being "right".

[0037] In this specification, "occupant" means, for example, a person with a physique equivalent to an average American male, conforming to the standards of the NHTSA [National Highway Traffic Safety Administration] [49CFR Part 572 Subpart E and O] for frontal crash testing (Hybrid III AM50 / Human body dummy for frontal crash testing). The approximate dimensions of the AM50 are a height of 175 cm, a sitting height of 88 cm, and a weight of 78 kg. However, the present invention is also applicable to other human body dummies.

[0038] In this specification, "painting" means covering a target area with paint. Applying a primer to improve the adhesion of the paint before covering the target area with the paint is also included in "painting."

[0039] [Configuration of the driver's side airbag system] As shown in Figure 1, the driver's side airbag system 10 is equipped with a cover 20 and is mounted on the steering wheel 1. The steering wheel 1 is equipped with a substantially annular rim portion 2 that is gripped by the occupant seated in the driver's seat when driving, a boss portion 3 located in the center of the inside of the rim portion 2, and a plurality of spoke portions 4 that connect the rim portion 2 and the boss portion 3. The steering wheel 1 is composed of the wheel body portion 5 and the driver's side airbag system 10. The driver's side airbag system 10 is located on the upper part of the boss portion 3.

[0040] As shown in Figures 1 and 2, the wheel body 5 comprises core metals 6 arranged in the rim portion 2, boss portion 3, and spoke portion 4, and a surface portion 7 made of a synthetic resin such as foamed polyurethane that covers the outer circumferential surface of the core metals 6 in the rim portion 2 and the outer circumferential surface of the core metals 6 in the spoke portion 4. Furthermore, all or part of the outer circumferential surface of the surface portion 7 is covered with natural or artificial leather.

[0041] The driver's side airbag system 10 includes an airbag module 11 consisting of an airbag cushion 12 and an inflator 13.

[0042] The airbag cushion 12 is a cloth bag constructed by preparing a required number of base fabrics of the desired shape in advance and sewing predetermined areas such as the outer periphery of these base fabrics. However, the airbag cushion 12 may also be formed into a bag shape by weaving using OPW (one-piece weaving) technology. The airbag cushion 12 can be stored by rolling it up in a roll shape or folding it in an accordion shape when laid flat. The inflation part of the airbag cushion 12 may be partitioned by multiple chambers.

[0043] The inflator 13 is a gas generator and is electrically connected to a control unit such as an ECU. Gas ejection holes are provided on the side of the inflator 13. The driver's side airbag system 10 is configured such that when a collision occurs in the vehicle, a sensor installed in the vehicle detects the impact, and the inflator 13 is activated by a signal from the control unit connected to the sensor.

[0044] As shown in FIG. 2, the driver's airbag device 10 includes an airbag cushion 12 in a stored state, an inflator 13 that ejects gas for inflating the airbag cushion 12, and a dome-shaped cover 20 that covers the upper part of the airbag cushion 12 in the stored state.

[0045] The holder part 14 holds the airbag cushion 12, the inflator 13, and the cover 20. The retainer 15 presses the periphery of the opening 12a of the airbag cushion 12 and is a member for attaching the airbag cushion 12 and the inflator 13 to the holder part 14. The airbag cushion 12 and the inflator 13 are attached to the holder part 14 by passing a bolt 16 through the periphery of the opening 12a of the airbag cushion 12 and the holder part 14 and screwing a nut 17 in a state where it protrudes from the lower surface side of the flange part 13a of the inflator 13.

[0046] The cover

[0046] 20 is integrally formed of a synthetic resin material such as an olefin-based thermoplastic elastomer (TPO) by injection molding or extrusion molding. As shown in FIG. 2, the cover 20 includes a surface part

[0046] 21 that covers the upper part of the folded airbag cushion 12 and a side wall part

[0046] 22 having a substantially square tubular shape that extends downward from the lower surface of the surface part

[0046] 21. As shown in FIG. 1, an emblem

[0046] 25 is formed in a groove part

[0046] 30 provided with a painting part

[0046] 40 at the central part of the surface part

[0046] 21 of the cover

[0046] 20.

[0047] On the surface portion 21, a first door portion 23 and a second door portion 24 are arranged side by side, which will be in a state of being opened in the front-rear direction with the planned breaking portion 26 as a boundary when the airbag cushion 12 expands and inflates. The planned breaking portion 26 is a portion more vulnerable than other portions of the surface portion 21. A tear line including the planned breaking portion 26 is formed around the first door portion 23 and the second door portion 24. When the inflator 13 operates during a vehicle collision, the gunpowder of the inflator 13 burns and the inflation gas is ejected from the ejection holes, and the inflation gas is supplied to the airbag cushion 12. As a result, the airbag cushion 12 expands rapidly, and the inflation pressure pushes up the surface portion 21 of the cover 20 upward, and the planned breaking portion 26 cracks. Then, the airbag cushion 12 protrudes greatly from between the first door portion 23 and the second door portion 24, expands and inflates between the occupant sitting on the driver's seat and the steering wheel 1, and restrains and protects the occupant.

[0048] [Structure and Painting Process of Emblem] Next, the structure of the cover 20 in which the emblem 25 is formed by the groove portion 30 provided with the painting portion 40 and the method of providing the painting portion 40 in the groove portion 30 of the cover 20 will be described in detail.

[0049] As shown in FIGS. <000009>) and <0), the driver's airbag device 10 includes a cover 20 that covers the airbag module 11 mounted on the steering wheel 1, and a groove portion 30 provided on the surface portion 21 of the cover 20 that shows the design shape of the emblem 25. For the emblem 25, an arbitrary logo composed of characters, figures, symbols such as the company logo of an automobile manufacturer or the logo of a specific vehicle model can be used. In this embodiment, as an example, as shown in FIGS. <000009>) and <0), an emblem 25 composed of the four alphabetical characters "Auto" is used. The groove portion 30 is provided on the surface of the surface portion 21 of the cover 20 on the side of the first door portion 23.

[0050] On the surface portion 21 of the cover 20, a painted portion 40 is provided in the area inside the groove portion 30. The present invention does not preclude painting areas other than the groove portion 30 of the cover 20, but in this embodiment, painting is performed only in the recessed area inside the groove portion 30. The groove portion 30 has a painted portion 40 formed in it that is a different color from the areas of the cover 20 other than the groove portion 30. The thickness of the painted portion 40 can be the same as the depth of the groove portion 30. Alternatively, the thickness of the painted portion 40 can be designed to be the same as the depth of the groove portion 30 as a standard, so that it falls within an acceptable range during the painting process.

[0051] The groove 30 is a recessed portion provided on the surface 21, which is lower than the cover surface. If the painted portion 40 provided in the groove 30 is too thick, it is prone to cracking and peeling, and if the drying of the inside is slow and the surface dries first, it is prone to wrinkling. Also, if the painted portion 40 is too thin, its durability will decrease. Therefore, it is preferable to design the thickness of the painted portion 40 to an appropriate thickness according to the physical properties of the paint used.

[0052] The inner region of the groove 30 includes a bottom surface 31 and a side surface 32 extending in a direction intersecting the bottom surface 31. The angle at which the bottom surface 31 and the side surface 32 intersect can be, for example, 90°. Alternatively, the cover 20 can be designed so that the angle falls within an acceptable range during molding, using 90° as a reference.

[0053] In this embodiment, a coating apparatus 100 equipped with a dispenser 101 (liquid quantitative dispensing mechanism) is used as a means for applying primer or paint to the groove 30.

[0054] The dispenser 101 of the painting apparatus 100 is equipped with a jetting head 110 that dispenses primer and paint droplets downward, as shown in Figure 4, for example. The painting apparatus 100 is equipped with a moving mechanism (not shown) that can move the jetting head 110 to any position in three-dimensional space relative to the cover 20 which is the object to be painted, and a control unit (not shown) that controls the operation of the moving mechanism and controls the amount of liquid droplets dispensed by the jetting head 110.

[0055] As an example, the jetting head 110 includes a piezo actuator 111 having a piezoelectric element, and a transmission rod 112 connected to one end of the piezo actuator 111 via a connecting member, which moves up and down in accordance with the extension and contraction of the piezo actuator 111. The jetting head 110 includes a nozzle 114 that discharges paint 113 by the action of the transmission rod 112. An outlet 115 is formed at the tip of the nozzle 114, from which the paint 113 is discharged in a predetermined width. The vibration frequency of the piezo actuator 111 can be freely changed by changing the frequency at the instruction of the control unit. In Figure 4(a), the piezo actuator 111 is shown in a retracted state, and the transmission rod 112 is located away from the outlet 115 of the nozzle 114. In Figure 4(b), the piezo actuator 111 is shown in an extended state, and the transmission rod 112 is in contact with the outlet 115 of the nozzle 114. At this time, the paint 113 stored between the tip of the transmission rod 112 and the discharge port 115 is pushed out by the transmission rod 112 and air pressure, and discharged from the discharge port 115 toward the groove 30.

[0056] Here, the diameter of the discharge port 115 of the nozzle 114 of the dispenser 101 is made narrower than the width of the groove 30 provided on the surface portion 21 of the cover 20. Specifically, the diameter of the discharge port 115 is a few millimeters or less, and if necessary, the diameter of the discharge port 115 may be in the range of several hundred micrometers to 1 mm.

[0057] Furthermore, by switching the paint 113 to a primer, the same painting apparatus 100 can be used to apply the primer to the grooves 30. A suitable primer can be used depending on the type of paint; for example, a chlorinated polypropylene-based primer can be used.

[0058] The painting apparatus 100 is not limited to the above configuration equipped with a piezoelectric element; for example, it may be an apparatus equipped with an air pump capable of applying discharge pressure, which applies a predetermined air pressure to the paint 113 and supplies it to the nozzle 114.

[0059] Figure 5 is a perspective view showing paint 113 being discharged from the nozzle 114 of the painting apparatus 100 into the groove 30 immediately after its formation, before the painted section 40 is provided. The groove 30 consists of a first groove 30a representing the letter "A", a second groove 30b representing the letter "u", a third groove 30c representing the letter "t", and a fourth groove 30d representing the letter "o".

[0060] The first groove 30a has a bottom surface 31a and a side surface 32a extending in a direction intersecting the bottom surface 31a. The second groove 30b also has a bottom surface 31b and a side surface 32b extending in a direction intersecting the bottom surface 31b. Furthermore, the third groove 30c has a bottom surface 31c and a side surface 32c extending in a direction intersecting the bottom surface 31c, and the fourth groove 30d has a bottom surface 31d and a side surface 32d extending in a direction intersecting the bottom surface 31d. As can be seen from Figure 5, the first groove 30a, the second groove 30b, the third groove 30c, and the fourth groove 30d are each independent concave regions, and the grooves 30 are not continuous.

[0061] The control unit of the painting apparatus 100 is composed of an information processing unit. Specifically, the control unit includes a CPU, a volatile memory unit such as RAM, a non-volatile memory unit such as an SSD or hard disk, a display device such as a display device, an input device such as a keyboard, and a control program. The painting apparatus 100 discharges a predetermined amount of primer or paint 113 from the nozzle 114 toward each groove 30 by controlling the extension and retraction of the piezo actuator 111 using the control unit.

[0062] In addition, the control unit of the painting apparatus 100 controls the operation of the moving mechanism to which the cover 20 is set. This allows for the control of distinguishing between paths in which the nozzle 114 moves while discharging primer or paint 114, such as within the area of ​​the letter "A" in the first groove 30a, and paths in which the nozzle 114 moves without discharging, such as when moving from the letter "A" in the first groove 30a to the "u" in the second groove 30b. The trajectory of the jetting head 110 basically passes through the center of each recess that forms the letters "A", "u", "t", and "o", and painting is performed while controlling the amount of primer or paint droplets 113 so that the width of each recess can be coated in one go. On the other hand, in areas where the primer or paint 113 becomes too thin with a single application and a sufficient primer layer 41 and paint layer 42 cannot be formed, multiple applications may be made.

[0063] In the driver's seat airbag device 10 cover 20 of this embodiment, the painted portion 40 is composed of a primer layer 41 provided so as to cover at least the bottom surface 31 of the area inside the groove portion 30, and a paint layer 42 provided so as to cover the primer layer 41, as shown in Figure 6(a).

[0064] To provide such painted areas 40 in the grooves 30, one example is to use the painting apparatus 100 described above and first discharge primer from the nozzle 114 onto each groove 30. Specifically, as shown in Figure 6(a), for example, when primer is applied to the center of the bottom surface 31c of the third groove 30c, the primer spreads to the corners of the bottom surface 31c, forming a primer layer 41 that covers the entire bottom surface 31c. After the primer layer 41 has dried and set, the painting apparatus 100 is used to discharge paint 113 from the nozzle 114 onto the third groove 30c. This forms a paint layer 42 that covers the primer layer 41.

[0065] In the cover 20 of the driver's side airbag device 10, by using the painted portion 40 with the above configuration, the adhesion strength of the paint layer 42 to the groove portion 30 is increased, and the paint layer 42 can be more firmly bonded to the groove portion 30 of the cover 20.

[0066] Furthermore, when forming the primer layer 41, the amount of primer discharged from the nozzle 114 of the painting apparatus 100 may be slightly increased so that the primer layer 41 covers not only the bottom surface 31c but also part or all of the side surface 32c, as shown in Figures 6(b) to (c). In this case as well, the process of forming the paint layer 42 on top of the primer layer 41 remains the same.

[0067] According to the driver's seat airbag device 10 cover 20 of this embodiment described above, the emblem 25 can be easily provided by the groove 30 and painted portion 40 without using an emblem plate, thus streamlining the manufacturing process of the cover 20.

[0068] Furthermore, according to cover 20, since no emblem plate is used, there is no risk of the aged emblem plate flying off when the airbag module 11 is activated.

[0069] Furthermore, although the cover 20 of this embodiment is made of an olefin-based thermoplastic elastomer (TPO), in the case of polyolefin resins, for example, they do not have functional groups that bond with the coating resin, so even if paint is applied directly, the adhesion is poor and there is a risk of cracking of the coating due to changes over time. However, in the cover 20 of this embodiment, the groove portion 30 has a bottom surface 31 and a side surface 32 extending in a direction intersecting the bottom surface 31, and the painted portion 40 is configured to consist of a primer layer 41 provided so as to cover at least the bottom surface 31 and a paint layer 42 provided so as to cover the primer layer 41, so the adhesion strength of the paint layer 42 is increased and the paint layer 42 is more firmly bonded to the groove portion 30 of the cover 20.

[0070] [Modification of the Embodiment] As shown in Figure 2, the cover 20 of this embodiment described above has a shape that is curved in a convex shape toward the upper side (towards the occupant seated in the driver's seat).

[0071] Therefore, as shown in Figure 7 (cross-section of the cover 20 in the left-right direction across the text of the emblem 25), the bottom surfaces 31a of the first groove 30a, 31b of the second groove 30b, 31c of the third groove 30c, and 31d of the fourth groove 30d are not parallel to each other. Each groove 30 has sides 32 that are perpendicular to the tangent line at the position of each groove 30 on the outer shape of the cover 20, and each bottom surface 31 is perpendicular to each side 32. If the bottom surfaces 31a, 31b, 31c, and 31d are connected by lines, they will have a curved shape that is roughly the same as the cover 20.

[0072] As a result, as shown in Figure 9(a), when primer is discharged from the nozzle 114 of the coating apparatus 100 onto the bottom surface 31d of the fourth groove 30d, for example, because the bottom surface 31d is inclined, the discharged primer tends to concentrate in the lower corner of the bottom surface 31d, resulting in an uneven thickness of the formed primer layer 41. Depending on the degree of inclination of the bottom surface 31d, there is also a risk that a gap 43 may occur where the primer layer 41 is absent in a part of the bottom surface 31d. In this way, if the thickness of the primer layer 41 is not uniform, or if there is a gap 43 where the primer layer 41 is absent, the effect of the primer may not be fully realized, and the paint layer 42 may become prone to peeling.

[0073] In contrast, in this modified example, as shown in Figure 8, when the cover 20 is installed so that the plane containing the straight line connecting one end 21a and the other end 21b of the surface portion 21 is horizontal, each of the grooves 50 is provided on the surface portion 21 such that each bottom surface 51 of the grooves 50 extends in the horizontal direction. In this modified example, the bottom surface 51a of the first groove 50a, the bottom surface 51b of the second groove 50b, the bottom surface 51c of the third groove 50c, and the bottom surface 51d of the fourth groove 50d are parallel to each other and each extends in the horizontal direction.

[0074] Although the cover 20 is inclined when the steering wheel 1 is attached to the steering shaft 8, the phrase "each extends horizontally" means that when the cover 20 is installed so that the plane containing the straight line connecting one end 21a and the other end 21b of the surface portion 21 is horizontal, each of the bottom surfaces 51 of the multiple groove portions 50 extends horizontally.

[0075] In this modified example, for instance, when primer is discharged from the nozzle 114 of the coating apparatus 100 onto the bottom surface 51d of the fourth groove 50d, the primer layer 41 is formed with a uniform thickness over the entire bottom surface 51d because the bottom surface 51d is horizontal, as shown in Figure 9(b). Similarly, for the first groove 50a, second groove 50b, and third groove 50c shown in Figure 8, the bottom surfaces 51a, 51b, and 51c are all horizontal, resulting in a uniform thickness of the primer layer 41.

[0076] Thus, in this modified example, when the cover 20 is molded, the bottom surfaces 51 of each of the multiple grooves 50 are formed to extend horizontally, so that the thickness of the primer layer 41 formed by the discharge of the primer is made uniform for each groove 50. As a result, the effect of the primer layer 41 is obtained uniformly across the entire area of ​​the bottom surface 51 of each groove 50, making it possible to more reliably increase the adhesion strength of the paint layer 42.

[0077] [Summary of Manufacturing Method] The method for providing the painted portion 40 in the groove portion 30 of the cover 20 in this embodiment and the method for providing the painted portion 40 in the groove portion 50 of the cover 20 in a modified example will be explained below.

[0078] The manufacturing method for the driver's seat airbag device 10 of this embodiment includes a first step of providing a groove 30 for forming an emblem 25 on the surface portion 21 of the cover 20 that covers the airbag module 11 mounted on the steering wheel 1, and a second step of providing a painted portion 40 by applying paint only to the area inside the groove 30 of the surface portion 21 using a painting apparatus 100 equipped with a dispenser 101.

[0079] Specifically, as shown in Figure 10, in the first step S1, step S2 determines whether the bottom surface of each groove is in a normal shape or parallel and horizontal to each other. If it is in a normal shape, step S3 is performed in the molding process of the cover 20 to form the groove 30 shown as an example in Figure 7. If it is to be horizontal, step S4 is performed to form the groove 50 shown as an example in Figure 8.

[0080] Steps S3 and S4 include the process of forming grooves 30 and 50, which have bottom surfaces 31 and 51 and side surfaces 32 and 52 extending in a direction intersecting the bottom surfaces 31 and 51.

[0081] Step S4 includes the step of providing each bottom surface 51 of the plurality of grooves 50 such that each bottom surface 51 extends in the horizontal direction when the cover 20 is installed so that the plane connecting one end 21a and the other end 21b of the surface portion 21 is horizontal.

[0082] In step S5, the molded cover 20 is set on the workpiece where the object to be discharged is to be placed below the nozzle 114 of the painting apparatus 100.

[0083] In the second step S6, step S7 is performed, which includes a primer layer formation step in which a primer layer 41 is provided using a coating apparatus 100 equipped with a dispenser 101 so as to cover at least the bottom surfaces 31 and 51. In step S8, the primer layer 41 is dried. Then, step S9 is performed, which includes a paint layer formation step in which a paint layer 42 is provided so as to cover the primer layer 41. In step S10, the painted part 40 including the paint layer 42 is dried.

[0084] The present invention is not limited to the examples described above, and it goes without saying that the embodiments may be modified as appropriate, as long as they fall within the scope of the technical ideas described in each claim.

[0085] In other words, the embodiments and their modifications described above are preferred examples of the present invention, and other embodiments can be adopted in various ways. Unless otherwise stated in this specification, the present invention is not limited to the shape, size, and configuration of the parts shown in the accompanying drawings.

[0086] For example, in the embodiments shown in Figures 1 and 2, the groove 30 that forms the emblem 25 is provided on the first door portion 23 side of the surface portion 21 of the cover 20, but the groove 30 may also be provided on the second door portion 24 side.

[0087] Furthermore, in the present invention, the groove 30 provided on the surface portion 21 of the cover 20 may be provided on both the first door portion 23 and the second door portion 24 that rupture when the airbag cushion 12 inflates and deploys.

[0088] In conventional covers that use an emblem plate, the tear line of the planned break section is usually designed to avoid the emblem plate so that it does not scatter when the airbag module is deployed. In contrast, the present invention does not use an emblem plate, and the emblem 25 can be formed by the groove 30 and the painted section 40. For this reason, in the present invention, even if the groove 30 is present in both the first door section 23 and the second door section 24, and the emblem 25 is formed so as to straddle the planned break section 26, no particular problems occur when the airbag module 11 is deployed.

[0089] Furthermore, in the modified example shown in Figure 8, when the cover 20 is installed so that the straight line connecting one end 21a and the other end 21b of the surface portion 21 is horizontal, an example is shown in which the bottom surfaces 51 of all grooves 50 from the first groove 50a to the fourth groove 50d extend in the horizontal direction. However, this modified example is not limited to this. The main point of the modified example shown in Figure 8 is that the bottom surfaces 51 of multiple grooves 50 extend in the horizontal direction, and a configuration that includes some grooves 50 whose bottom surfaces 51 do not extend in the horizontal direction is also included in the gist of the invention of this modified example.

[0090] To give a specific example, the modified example shown in Figure 8 includes an embodiment in which, with respect to the groove 50 provided on the surface portion 21 of the cover 20, the total area of ​​all bottom surfaces 51 of the groove 50 is GA, and the total area of ​​the bottom surfaces 51 of the groove 50 that are molded to be parallel to each other and extend horizontally is TA, and the value of TA / GA is within the following range.

[0091] TA / GA=1.0 TA / GA≧0.9 TA / GA≧0.8 TA / GA≧0.7 TA / GA≧0.6

[0092] In other words, the embodiment includes not only a configuration in which all bottom surfaces 51 of the groove 50 are provided to extend horizontally, but also, for example, a configuration in which 90% or more, 80% or more, 70% or more, and 60% or more of the total area of ​​the bottom surface 51 are provided to extend horizontally.

[0093] 1 Steering wheel 10 Driver's side airbag device 11 Airbag module 20 Cover 21 Surface 21a One end 21b Other end 25 Emblem 30 Groove 31 Bottom 32 Side 40 Painted part 41 Primer layer 42 Paint layer 50 Groove 51 Bottom 52 Side 100 Painting device 101 Dispenser 113 Paint

Claims

1. A driver's side airbag device comprising: a cover that covers an airbag module mounted on a steering wheel; a groove provided on the surface of the cover that forms an emblem; and a painted area provided in the region inside the groove.

2. The driver's seat airbag device according to claim 1, wherein the groove portion comprises a bottom surface and a side surface extending in a direction intersecting the bottom surface, and the painted portion comprises a primer layer provided so as to cover at least the bottom surface and a paint layer provided so as to cover the primer layer.

3. The driver's seat airbag device according to claim 1 or 2, wherein when the cover is installed such that the plane connecting one end and the other end of the surface portion is horizontal, the bottom surfaces of the plurality of groove portions are provided to extend horizontally.

4. The driver's seat airbag device according to claim 1 or 2, wherein the surface portion is painted only in the area inside the groove, and the area other than the groove is unpainted.

5. The driver's seat airbag device according to claim 3, wherein the surface portion is painted only in the area inside the groove, and the area other than the groove is unpainted.

6. A method for manufacturing a driver's side airbag device, comprising: a first step of providing a groove for forming an emblem on the surface of a cover that covers an airbag module mounted on a steering wheel; and a second step of providing a painted portion by applying paint to the area inside the groove using a painting apparatus equipped with a dispenser.

7. The method for manufacturing a driver's seat airbag device according to claim 6, wherein the first step includes providing the groove portion having a bottom surface and a side surface extending in a direction intersecting the bottom surface, and the second step includes a primer layer forming step of providing a primer layer so as to cover at least the bottom surface, and a paint layer forming step of providing a paint layer so as to cover the primer layer.

8. The method for manufacturing a driver's seat airbag device according to claim 7, wherein the first step includes the step of providing each of the bottom surfaces of the plurality of grooves such that each bottom surface extends horizontally when the cover is installed so that the plane connecting one end and the other end of the surface is horizontal.

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