Airbag module mounting structure to the steering wheel

Abstract

The present invention comprises: an engagement member 26 which is provided such that a base end 26a thereof is joined to a housing 15 of an airbag module and includes an engagement hole 28 on a distal end 26b side; an engagement projection 27 which is formed on a metal core 3 of the steering wheel such as to protrude upward from a lower position in the vertical direction of the steering wheel toward the center of the steering wheel with respect to the neutral position of the steering wheel as a reference and which is inserted into the engagement hole of the engagement member to attach the airbag module to the steering wheel; and an insulating member 32 provided between the engagement projection and the engagement hole to prevent contact between the engagement projection and the engagement hole engaged with the engagement projection.

Description

Technical Field

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[0001] The present invention relates to an attachment structure of an airbag module to a steering wheel, which has excellent assembly workability and enables reliable attachment.

Background Art

[0002] As a structure for attaching an airbag module equipped with a driver's seat airbag to a steering wheel, various configurations are known. For example, Patent Document 1 is known.

[0003] "Damping mechanism of steering wheel and vehicle steering wheel device" in Patent Document 1 is provided with two damping units between the steering wheel and the airbag module serving as a damping mass to damp the vibration of the steering wheel, and an engagement mechanism (hook of a plate-shaped damper) provided in parallel with the damping unit between the steering wheel and the airbag module to hold the steering wheel and the airbag module so that their relative displacement is possible.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

[0007] The present invention was devised in view of the above-mentioned conventional problems, and aims to provide a mounting structure for an airbag module to a steering wheel that offers excellent assembly workability and reliable installation. [Means for solving the problem]

[0008] The mounting structure for an airbag module to a steering wheel according to the present invention is characterized by comprising: an engaging member having an engagement hole at its tip end, which is attached to the housing of the airbag module at its base end; an engaging projection formed on the core metal of the steering wheel, projecting upward from a position below the steering wheel in the vertical direction toward the center of the steering wheel with respect to the neutral position of the steering wheel, and being inserted into the engagement hole of the engaging member to mount the airbag module to the steering wheel; and an insulating member provided between the engaging projection and the engagement hole to prevent contact between the engaging projection and the engagement hole engaged with the engaging projection.

[0009] Preferably, the engaging member is formed of a plate material that is flexible and elastically deformable, with the engaging hole formed through it, and the engaging projection has an inclined surface on which the tip of the engaging member slides along the direction in which the airbag module is attached to the steering wheel, the engaging member slides along the inclined surface and undergoes flexible deformation, and when the engaging hole reaches the end of the inclined surface the engaging member is elastically restored so that the engaging projection is inserted into the engaging hole.

[0010] The core metal of the steering wheel is formed in a casting mold that is divided by a parting line, and it is desirable that the parting line is set to cross the inclined surface.

[0011] The housing of the airbag module and the core metal of the steering wheel constitute a conductive circuit.

[0012] The airbag module is a damper mass, and it is preferable that a damper unit for damping vibrations of the steering wheel is provided between the steering wheel and the airbag module, in parallel with the engaging member. [Effects of the Invention]

[0013] The mounting structure for the airbag module to the steering wheel according to the present invention offers excellent assembly workability and ensures secure mounting. [Brief explanation of the drawing]

[0014] [Figure 1] This is a perspective view showing an example of a steering wheel to which the steering wheel mounting structure for the airbag module according to the present invention is applied. [Figure 2] This is a view of the main part of the steering wheel core in a preferred embodiment of the steering wheel mounting structure for an airbag module according to the present invention, as seen from the Z-axis direction. [Figure 3] This is an explanatory diagram showing an airbag module viewed from the X-axis direction in a preferred embodiment of the mounting structure for an airbag module to a steering wheel according to the present invention. [Figure 4] This is an explanatory diagram showing the back side of the airbag module shown in Figure 3. [Figure 5] Figure 3 is an exploded perspective view of the airbag module. [Figure 6] Figure 3 is an enlarged perspective view of an engaging member equipped with an insulating member, which is provided on the airbag module shown in Figure 3. [Figure 7] This is a schematic diagram illustrating a preferred embodiment of the mounting structure for an airbag module to a steering wheel according to the present invention, showing the initial mounting state (viewed from the direction of line AA in Figure 2). [Figure 8] Figure 3 is an explanatory diagram illustrating the engagement action between the engaging member of the airbag module and the engaging projection of the core metal. [Figure 9] It is an enlarged sectional view of a main part showing an engagement state between an engagement protrusion engaged by the engagement action of FIG. 8 and an engagement hole provided with an insulating member. [Figure 10] It is a perspective view of a main part showing an attachment state of the core metal shown in FIG. 2 and the airbag module shown in FIG. 3.

Mode for Carrying Out the Invention

[0015] Hereinafter, a preferred embodiment of an attachment structure of an airbag module according to the present invention to a steering wheel will be described in detail with reference to the accompanying drawings.

[0016] In FIGS. 1 to 5, a vehicle steering wheel 1 and an airbag module 2 attached thereto are shown.

[0017] FIG. 1 is a perspective view illustrating an overview of a steering wheel 1 to which an airbag module 2 is attached.

[0018] In the following drawings including FIG. 1, it is assumed that the steering position of the steering wheel 1 attached to the vehicle is in the neutral position, and each direction is illustrated.

[0019] The steering position being the neutral position means that the steering angle of the steering wheel 1 is "zero" and the front wheels to be steered face the straight-ahead direction.

[0020] In the figure, the direction of the Z-axis of the three-dimensional coordinate system is along the steering shaft not shown, with the direction of the front wheels downward and the direction of the steering wheel 1 upward.

[0021] Similarly, the direction of the X-axis of the three-dimensional coordinate system is from the 3 o'clock direction (right direction) to the 9 o'clock direction (left direction) of an analog clock in a plane orthogonal to the Z-axis, and the direction of the Y-axis is from the 12 o'clock direction (upward) to the 6 o'clock direction (downward) in the same plane. In addition, the side viewed from the driver's side is referred to as the front side, and the opposite side is described as the back side.

[0022] The steering wheel 1 is installed in the driver's seat of the vehicle, connected to the steering shaft, and transmits the driver's steering input to the steering gear, etc.

[0023] An airbag module 2, which functions as a driver's side airbag in an emergency, is located in the center of the steering wheel 1.

[0024] Airbag module 2 also functions as a horn switch, which is pressed by the driver to activate the horn under normal circumstances.

[0025] The airbag module 2 also functions as a modular damper to reduce vibrations in the steering wheel 1.

[0026] The base of the steering wheel 1 consists of a metal core 3 manufactured by casting.

[0027] The core metal 3 is roughly composed of a boss area 5 having a central boss hole 4, a rim 6 that the driver grips, and spokes 7 and 8 that connect the boss area 5 and the rim 6. The steering shaft is connected to the boss hole 4.

[0028] As shown in Figure 2, the boss area 5 is provided with a bridge portion 9 that connects the bases of the left and right spokes 7, located at a distance from the boss hole 4 at the 6 o'clock position (downward in the Y-axis direction) when the steering wheel 1 is in its neutral position.

[0029] The structure of the airbag module 2 will be briefly described with reference to Figures 1 and 3-5. The driver's side of the airbag module 2 is covered with a resin horn cover 10 that functions as a decorative surface.

[0030] Behind the horn cover 10 is a locking plate 12 to which the damper unit 11, described later, is fixed.

[0031] Inside the horn cover 10, a folded airbag cushion 13 is housed, which is deployed and inflated in an emergency.

[0032] An inflator 14, which is housed in an airbag cushion 13, is attached to the rocking plate 12.

[0033] In an emergency, when a signal is sent from the vehicle's sensors, inflator gas is supplied from the inflator 14 to the airbag cushion 13.

[0034] The airbag cushion 13, supplied with inflatable gas, opens the horn cover 10 and expands into the passenger compartment, restraining the driver.

[0035] The airbag module 2 consists of a metal locking plate 12, a metal housing 15 formed in a dish shape with a peripheral wall 15a on the surface side and two of them stacked on the surface of the locking plate 12, two hollow cylindrical damper units 11, a pin 16 slidably inserted into the hollow interior of the damper units 11, an inflator 14, a metal retainer ring 17 having a bolt 17a to which a nut 18 is fastened, which fixes the airbag cushion 13 and the inflator 14 to the housing 15, and a horn cover 10 which houses the airbag cushion 13.

[0036] The airbag cushion 13 has an insertion hole for inserting the inflator 14, although this is not shown in the figure. Bolt holes for the retainer ring 17 are formed around the insertion hole.

[0037] The retainer ring 17 is provided inside the airbag cushion 13. The retainer ring 17 is positioned in the insertion hole of the airbag cushion 13 so that the bolt 17a protrudes from the bolt insertion hole.

[0038] The locking plate 12 has a hole 12a in the center through which the inflator 14 is inserted. Two locking holes 12c are formed in the recesses 12b on either side of the hole 12a, for attaching and fixing the two damper units 11, respectively.

[0039] A hole 15b is formed inside the peripheral wall 15a of the dish-shaped housing 15, through which the inflator 14, which is inserted through the hole 12a of the locking plate 12, is inserted.

[0040] An airbag cushion 13 is installed in the housing 15, with its insertion hole aligned with the hole 15b. The area around the insertion hole of the airbag cushion 13 is sandwiched between the retainer ring 17 and the housing 15.

[0041] The damper unit 11 is mounted in the recess 12b from the front side (housing 15 side) of the locking plate 12 and is fixed to the locking plate 12 by the lock hole 12c.

[0042] The pin 16 has a head portion 16a at one end, is inserted into the damper unit 11 from the housing 15 side, and is provided passing through the lock hole 12c of the locking plate 12.

[0043] The head portion 16a of the pin 16 is sandwiched between the housing 15 and the locking plate 12 and held between them.

[0044] The inflator 14 has an outer peripheral flange 14a that abuts against the back surface of the locking plate 12.

[0045] The inflator 14 is inserted into the insertion hole of the airbag cushion 13 through the hole 12a of the locking plate 12, the hole 15b of the housing 15, and the retainer ring 17.

[0046] The bolts 17a of the retainer ring 17 protruding from the airbag cushion 13 pass through the housing 15, the locking plate 12, and the outer flange 14a of the inflator 14, and are fastened to nuts 18 on the back side of the locking plate 12.

[0047] As a result, the airbag cushion 18 and the inflator 14 are fixed to the housing 15, and the damper unit 11 is incorporated into the locking plate 12.

[0048] As shown in Figures 5 and 7, the horn cover 10 has a locking portion 10a at its rim that is locked to a locking portion 15c formed on the peripheral wall 15a of the housing 15.

[0049] The locking portion 10a of the horn cover 10 is further held in place by being sandwiched between the pressing portion 12d of the locking plate 12 and the locked portion 15c of the housing 15 when the locking plate 12 is assembled to the housing 15 (see Figure 7).

[0050] The damper unit 11 provided in the airbag module 2 is a component that elastically attaches the airbag module 2 to the core metal 3 of the steering wheel 1, and forms the center of the module damper.

[0051] Briefly speaking, as shown in Figure 5, the damper unit 11 is constructed by housing a ring-shaped elastic body 19 that dampens vibrations inside a holder 20, and securing an insulator plate 21 superimposed on one end of the elastic body 19 with a sleeve 22 that is inserted into and held inside the elastic body 19. The pin 16 is inserted into the sleeve 22.

[0052] The holder 20 is inserted into the locking hole 12c of the locking plate 12 and rotated relative to the locking hole 12c, thereby fixing it to the locking plate 12.

[0053] As shown in Figure 2, the two damper units 11 are aligned in the X-axis direction with respect to the neutral position of the steering wheel 1, and positioned towards the left and right sides of the airbag module 2.

[0054] As shown in Figure 3, a pin 16 protrudes from the damper unit 11 in the Z-axis direction toward the boss region 5 of the core metal 3.

[0055] By attaching this pin 16 to the core metal 3, the airbag module 2 is attached to and connected to the steering wheel 1 from the Z-axis direction via the damper unit 11.

[0056] As a result, a damper unit 11 is positioned between the airbag module 2 and the steering wheel 1 to dampen vibrations of the steering wheel 1.

[0057] The pin 16 is inserted through the coiled horn spring 23 and into the collar member 24 provided on the core metal 3. The pin 16 is attached to and held by the core metal 3 by the collar member 24 (see Figure 7).

[0058] In other words, the horn spring 23 is provided between the core metal 3 and the airbag module 2, and a gap for horn operation is secured between the core metal 3 and the airbag module 2.

[0059] As a result, the airbag module 2 is elastically supported by the horn spring 23 on the steering wheel 1 and is connected to the steering wheel 1 via the damper unit 11 in a way that allows it to move toward the steering wheel 1, i.e., to be pressed toward it.

[0060] Vibrations from the steering wheel 1 are transmitted to the damper unit 11 via the pin 16. The transmitted vibrations are damped by the elastic body 19 of the damper unit 11, with the airbag module 2 acting as the damper mass.

[0061] In this embodiment, the performance of the elastic body 19 is such that vibration damping is achieved by the damper units 11 provided at two locations in the airbag module 2, and it is preferable to increase the hardness of the elastic body 19, and it is desirable to set the Shore A rubber hardness to HS18 to HS80.

[0062] Regarding the horn function, when the airbag module 2 is pressed toward the steering wheel 1 in the Z-axis direction, the entire airbag module 2, including the damper unit 11, slides relative to the pin 16 held by the collar member 24 of the core metal 3, and the horn spring 23 is elastically compressed and deformed.

[0063] As a result, the contacts provided on the housing 15 and the core metal 3 of the airbag module 2 become electrically conductive, causing the horn to sound.

[0064] When the pressure on the airbag module 2 is released, the horn spring 23 elastically returns to its original position, causing the airbag module 2 to retract, which separates the contacts and stops the horn from sounding.

[0065] Therefore, the housing 15 of the airbag module 2 and the core metal 3 of the steering wheel 1 constitute a conductive circuit.

[0066] To ensure reliable operation of the horn, it is preferable to place an embossed surface (not shown) on the outer edge of the housing 15 as the contact point on the airbag module 2 side, and to place a copper rivet 25 on the core metal 3 as the contact point on the steering wheel 1 side, as shown in Figure 2.

[0067] In this embodiment, as a configuration for attaching the airbag module 2 to the steering wheel 1 from the Z-axis direction, as shown in Figures 6 to 10, an engaging member 26 is provided on the housing 15 and an engaging projection 27 is provided on the core metal 3.

[0068] The engaging member 26 is provided between the steering wheel 1 and the airbag module 2, in parallel with the damper unit 11 described above.

[0069] As shown in Figures 6 and 8, the engaging member 26 is formed from a plate material that is elastically deformable in the direction of the plate thickness.

[0070] The engaging member 26 has its base end 26a, which is one end in the longitudinal direction, joined to the peripheral wall 15a of the housing 15, thereby being provided on the airbag module 2 side.

[0071] An engagement hole 28 is formed on the tip 26b side, which is the other end in the longitudinal direction of the engaging member 26, extending through in the thickness direction. In the illustrated example, the engagement hole 28 is formed in a substantially rectangular shape in the longitudinal direction of the engaging member 26.

[0072] The tip 26b side of the engaging member 26 is provided with a pair of left and right ribs 26c that are bent toward the housing 15 side, positioned to sandwich the engaging hole 28 from both sides in the width direction of the engaging member 26.

[0073] As for the material used for the engaging member 26, stainless steel is the most preferred material in terms of the balance between elasticity, strength, and cost, and among these, SUS301 CSP 3 / 4H t0.6 is the most desirable.

[0074] The base end 26a of the engaging member 26 is joined to the peripheral wall 15a of the housing 15 by rivets 29 at two locations in the width direction of the engaging member 26, in order to ensure high rigidity against the tensile load generated between the steering wheel 1 and the airbag module 2.

[0075] An engaging projection 27 is integrally provided on the bridge portion 9 of the boss area 5, which is made up of the core metal 3 of the steering wheel 1, in a form that protrudes from the bridge portion 9.

[0076] The engaging projection 27 is formed to protrude upward toward the boss hole 4, which is the center of the steering wheel 1, from a position below the steering wheel 1 in the vertical direction, that is, from the bridge portion 9 at the 6 o'clock position, which is below the boss hole 4, relative to the neutral position of the steering wheel 1. As a result, the engaging projection 27 is positioned between the bridge portion 9 and the boss hole 4.

[0077] As shown in Figures 2 and 7, the engaging projection 27 is formed by an inclined surface 30 on the front side of the bridge portion 9 in the Z-axis direction, with the bridge portion 9 (front side) as the starting point 30a and extending diagonally upward toward the boss hole 4.

[0078] The engaging projection 27 has a flat engaging surface 31 on the back side of the bridge portion 9, which extends downward from the end 30b of the inclined surface 30 to the bridge portion 9 (back side). In other words, the engaging projection 27 is formed in an almost right-angled triangular shape when viewed from the X-axis direction.

[0079] The inclined surface 30 is formed in the direction of the Z-axis, which is the direction in which the airbag module 2 is attached to the steering wheel 1.

[0080] As shown in Figures 7 and 8, the tip 26b of the engaging member 26 slides along the inclined surface 30.

[0081] The width dimension of the engaging projection 27 in the X-axis direction is set so that it can be inserted into the engaging hole 28 of the engaging member 26.

[0082] When the tip 26b of the engaging member 26 slides along the inclined surface 30, the rectangular engaging hole 28 moves with the leading edge 28a, which is closer to the tip 26b of the engaging member 26, leading, and the trailing edge 28b, which is closer to the base end 26a of the engaging member 26, moving behind.

[0083] When the airbag module 2 is attached to the steering wheel 1 from the Z-axis direction, the tip 26b of the engaging member 26 is first positioned on the side of the starting end 30a of the inclined surface 30, as shown in Figure 8(a).

[0084] As the airbag module 2 is further pressed toward the steering wheel 1, as shown in Figure 8(b), the tip 26b of the engaging member 26 slides along the inclined surface 30 and is displaced toward the boss hole 4, causing the engaging member 26 to undergo elastic bending deformation.

[0085] As shown in Figure 8(c), when the leading edge 28a of the engagement hole 28 reaches the end 30b of the inclined surface 30 and exceeds the end 30b, the engagement member 26 is elastically restored and the engagement projection 27 is inserted into the engagement hole 28.

[0086] Then, as shown in Figures 9 and 10, the leading edge 28a of the engagement hole 28 inserted into the engagement projection 27 is locked onto the engagement surface 31 of the engagement projection 27.

[0087] As a result, the engaging projection 27 and the engaging hole 28 engage, and the airbag module 2 is attached to the core metal 3 of the steering wheel 1.

[0088] The inclined surface 30 allows the engaging member 26 to be smoothly bent and elastically deformed.

[0089] The core metal 3 of the steering wheel 1, which has spokes 7, 8, etc., a bridge portion 9, and a boss area 5 including engaging projections 27, is formed by pouring metal into a casting mold that is separated by a parting line P.

[0090] As shown in Figure 7, the parting line P is set to cross the inclined surface 30 so that no burrs or sharp edges are generated at the upper or lower ends of the engaging projection 27.

[0091] Furthermore, the inclined surface 30 may be polished or otherwise modified to make it more slippery. In this way, even if a parting line P remains, the engaging member 26 can be smoothly elastically deformed.

[0092] This prevents obstruction of the assembly of the engaging member 26 onto the engaging projection 27 and prevents damage to the engaging member 26, allowing for smooth assembly.

[0093] Between the engaging projection 27 and the engaging hole 28, an insulating member 32 is provided as a covering material to prevent contact between the engaging projection 27 and the engaging hole 28 engaged with the engaging projection 27, thereby insulating electrical conduction. In this embodiment, the insulating member 32 is provided on the engaging member 26 having the engaging hole 28.

[0094] The insulating member 32 is made of a non-conductive material such as synthetic resin. The insulating member 32 is provided in alignment with the position of the rib 26c of the engaging member 26.

[0095] As shown in Figures 6 and 9, the insulating member 32 is fitted into the bent portion 28c of the front edge 28a of the engagement hole 28, which covers both the front and back surfaces of the engagement member 26, including the rib 26c, and engages with the engagement surface 31 of the engagement projection 27, thereby covering the front edge 28a.

[0096] Therefore, the rear edge 28b side of the engagement hole 28 may or may not be covered with the insulating member 32.

[0097] Figure 9 shows how the engagement hole 28 engages with the engagement projection 27. The insulating member 32 provided on the leading edge 28a of the engagement hole 28, including the rib 26c and the bent portion 28c, engages with the engagement surface 31 of the engagement projection 27.

[0098] As a result, this insulating member 32 ensures quiet operation, wear resistance, and impact resistance at the engagement point in all X, Y, and Z axis directions at a low cost.

[0099] In the Z-axis direction, the airbag module 2 is mounted on the core metal 3 of the steering wheel 1 by the elastic action of the horn spring 23.

[0100] Therefore, with respect to the engaging projection 27 of the core metal 3, only the leading edge 28a of the engaging hole 28 of the engaging member 26 on the airbag module 2 side is engaged with the engaging surface 31.

[0101] This insulates only the leading edge 28a of the engagement hole 28 and its surrounding area from the engagement projection 27, thereby interrupting electrical conductivity between the core metal 3 and the housing 15 of the airbag module 2.

[0102] In this embodiment, as shown in Figure 4, a pair of coil springs 33 are arranged on both sides of the engaging member 26 in the X-axis direction on the locking plate 12 of the airbag module 2 via bushings 34 (see Figure 5).

[0103] These coil springs 33 ensure a support structure for the airbag module 2 around the engaging member 26 located at the 6 o'clock position, that is, stable support for the airbag module 2 when the horn is not operated, and good pressability of the airbag module 2 when the horn is operated.

[0104] The operation of the mounting structure for the airbag module 2 to the steering wheel 1 according to this embodiment will be explained with reference to Figures 7 to 10.

[0105] When attaching the airbag module 2 to the steering wheel 1, as shown in Figure 7, the pin 16 inserted through the damper unit 11 faces the collar member 24 near the boss hole 4 of the core metal 3 from the Z-axis direction, and the tip 26b of the engaging member 26, which is provided with an insulating member 32, is brought into contact with the starting end 30a of the inclined surface 30 of the engaging projection 27.

[0106] Next, as shown in Figure 8, the airbag module 2 is pressed toward the core metal 3 in the Z-axis direction, causing the engaging member 26 to move along the inclined surface 30 of the engaging projection 27 and undergo bending elastic deformation.

[0107] Finally, the elastic restoring action of the engaging member 26 causes the engaging projection 27 to be inserted into the engaging hole 28.

[0108] When the engaging projection 27 is inserted into the engaging hole 28, as shown in Figure 9, the insulating member 32 comes into contact with the engaging surface 31 of the engaging projection 27, and the core metal 3 and the airbag module 2 including the engaging member 26 are engaged in an electrically insulated state.

[0109] As a result, as shown in Figure 10, the engaging member 26 joined to the housing 15 of the airbag module 2 surrounds the engaging projection 27 with the engaging hole 28, and the leading edge 28a of the engaging hole 28 engages with the engaging surface 31 of the engaging projection 27, thereby attaching the airbag module 2 to the core metal 3 of the steering wheel 1.

[0110] Almost simultaneously with this installation, the damper unit 11 is coupled to the collar member 24 of the boss area 5 via the pin 16, completing the connection between the airbag module 2 and the steering wheel 1 via the damper unit 11.

[0111] In the mounting structure of the airbag module to the steering wheel according to this embodiment, the mounting is performed by inserting the engaging projection 27 into the engaging hole 28, that is, by an engaging action in which the engaging projection 27 is surrounded by the engaging hole 28.

[0112] Therefore, when attaching the airbag module 2, which transmits vibrations, to the steering wheel 1, a secure attachment can be ensured in which the engagement portion between the engagement member 26 and the engagement projection 27 does not cause any looseness in all directions of the X, Y, and Z axes.

[0113] Furthermore, an insulating member 32 is provided on the engaging member 26 to cover the leading edge 28a of the engaging hole 28 and its surrounding area. This ensures electrical insulation between the engaging member 26 provided on the housing 15 and the core metal 3 on which the engaging projection 27 is formed, allowing the horn to operate properly.

[0114] Furthermore, by inserting the engaging projection 27 into the engaging hole 28 and installing the insulating member 32 in the engaging hole 28, quietness, wear resistance, and impact resistance can also be ensured at the engaging portion.

[0115] As the airbag module 2 is attached to the steering wheel 1, the engaging member 26 is bent and elastically deformed by the inclined surface 30 of the engaging projection 27.

[0116] Therefore, the engaging projection 27 and the engaging hole 28 can be engaged simply by pressing the airbag module 2, making the installation operation extremely easy and providing excellent assembly workability.

[0117] The mounting structure of the airbag module to the steering wheel described above is a preferred example of the present invention, and other embodiments can be implemented or carried out in various ways. In particular, unless otherwise stated in this specification, the present invention is not limited to the detailed shapes, sizes, and configurations of the parts shown in the accompanying drawings. Furthermore, the expressions and terms used in this specification are for illustrative purposes only and are not limited thereto unless otherwise stated in this specification.

[0118] [Note 1] The mounting structure for the airbag module 2 to the steering wheel 1 includes an engaging member 26 whose base end is joined to the housing 15 of the airbag module 2 and which has an engaging hole 28 on its tip end; an engaging projection 27 formed on the core metal 3 of the steering wheel 1, projecting upward from a position below the steering wheel 1 in the vertical direction toward the center of the steering wheel 1 with respect to the neutral position of the steering wheel 1, and inserted into the engaging hole 28 of the engaging member 26 to attach the airbag module 2 to the steering wheel 1; and an insulating member 32 provided between the engaging projection 27 and the engaging hole 28 to prevent contact between the engaging projection 27 and the engaging hole 28 which is engaged with the engaging projection 27.

[0119] [Note 2] In the mounting structure for the airbag module 2 to the steering wheel 1 described in Appendix 1, the engaging member 26 is formed of a plate material that is flexible and deformable, with an engaging hole 28 formed through it. The engaging projection 27 has an inclined surface 30 on which the tip 26b side of the engaging member 26 slides along the direction in which the airbag module 2 is mounted to the steering wheel 1. The engaging member 26 slides on the inclined surface 30 and undergoes flexible deformation. When the engaging hole 28 reaches the end 30b of the inclined surface 30, the engaging member 26 is elastically restored, and the engaging projection 27 may be inserted into the engaging hole 28.

[0120] [Note 3] In the mounting structure of the airbag module 2 to the steering wheel 1 described in Appendix 1, the core metal 3 of the steering wheel 1 is formed by a casting mold that is divided by a parting line P, and the parting line P is set to cross the inclined surface 30.

[0121] [Note 4] In the mounting structure of the airbag module 2 to the steering wheel 1 described in any one of the appendices 1 to 3, the housing 15 of the airbag module 2 and the core metal 3 of the steering wheel 1 may form an conductive circuit.

[0122] [Note 5] In the mounting structure of the airbag module 2 to the steering wheel 1 described in any one of the appendices 1 to 4, the airbag module 2 is a damper mass, and a damper unit 11 for damping vibrations of the steering wheel 1 may be provided between the steering wheel 1 and the airbag module 2 in parallel with the engaging member 26. [Explanation of symbols]

[0123] 1. Steering wheel 2 Airbag Modules 3. Core 11 Damper Unit 15 Housing 26 Engaging member 26a Base end of engaging member 26b Tip of the engaging member 27 Engagement protrusion 28 Engagement holes 30 Slope 30b End of the inclined surface 32 Insulating material P parting line

Claims

1. An engaging member is provided, with its base end joined to the housing of the airbag module and having an engaging hole on its tip end. The steering wheel core has an engaging projection that protrudes upward from a position below the steering wheel in the vertical direction toward the center of the steering wheel, relative to the neutral position of the steering wheel, and is inserted into the engaging hole of the engaging member to attach the airbag module to the steering wheel, An insulating member is provided between the engaging projection and the engaging hole to prevent contact between the engaging projection and the engaging hole engaged with the engaging projection, Between the steering wheel and the airbag module, there is a damper unit provided in parallel with the engaging member to dampen vibrations of the steering wheel, The engagement member is formed from a plate material that has the engagement hole formed through it and is flexible and deformable. The engaging projection has an inclined surface on which the tip side of the engaging member slides along the direction in which the airbag module is attached to the steering wheel, The inclined surface has a start end and an end end, When attaching the airbag module to the steering wheel, The starting end of the inclined surface is configured such that the tip of the engaging member contacts the pin inserted through the damper unit when the pin is brought toward the collar member near the boss hole of the core metal from the direction of attachment to the steering wheel. When the airbag module is further pressed toward the core metal after this contact, the engaging member slides from the starting end to the ending end on the inclined surface, causing bending elastic deformation. The mounting structure for an airbag module to a steering wheel is characterized in that the end of the inclined surface is configured such that when the engagement hole reaches the end, the engagement member elastically returns to its original position and inserts the engagement hole into the engagement projection.

2. An engaging member having an engagement hole on its tip side, which is attached to the housing of the airbag module at its base end, The steering wheel core has an engaging projection that protrudes upward from a position below the steering wheel in the vertical direction toward the center of the steering wheel, relative to the neutral position of the steering wheel, and is inserted into the engaging hole of the engaging member to attach the airbag module to the steering wheel, The device comprises an insulating member provided between the engaging projection and the engaging hole, which prevents contact between the engaging projection and the engaging hole engaged with the engaging projection, The engagement member is formed from a plate material that has the engagement hole formed through it and is flexible and deformable. The engaging projection has an inclined surface on which the tip of the engaging member slides along the direction in which the airbag module is attached to the steering wheel. The above engaging member slides along the inclined surface, causing bending elastic deformation. The engaging member, upon reaching the end of the inclined surface through the engagement hole, is elastically restored, and the engaging projection is inserted into the engagement hole. The mounting structure for an airbag module to a steering wheel is characterized in that the core metal of the steering wheel is formed by a casting mold that is divided by a parting line, and the parting line is set to cross the inclined surface.

3. The mounting structure for an airbag module to a steering wheel according to claim 1 or 2, characterized in that the housing of the airbag module and the core metal of the steering wheel constitute an conductive circuit.

4. The mounting structure for an airbag module to a steering wheel according to claim 1, wherein the damper unit is configured to be coupled to the collar member via the pin at approximately the same time that the engaging projection is inserted into the engaging hole and the airbag module is attached to the steering wheel.

5. The mounting structure for an airbag module to a steering wheel according to claim 1 or 2, wherein the insulating member is made of a non-conductive material and is installed in the engagement hole.

6. The tip side of the engaging member is provided with a pair of ribs that are bent toward the housing side, arranged to sandwich the engaging hole from both sides in the width direction of the engaging member, The mounting structure for an airbag module to a steering wheel according to claim 1 or 2, wherein the insulating member is provided on the engaging member in accordance with the position of the rib.

7. The mounting structure for an airbag module to a steering wheel according to claim 6, wherein the insulating member covers both sides of the engaging member, including the rib, and is fitted into the bent portion of the front edge of the engaging hole, which is engaged with the engaging surface of the engaging projection, and covers the front edge.

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