JPH08295201A - Steering wheel provided with air bag device - Google Patents

Abstract

PURPOSE: To provide a steering wheel wherein designing in an upper surface side and connecting workability to a steering shaft can be improved, to facilitate arranging an air bag device further with an air bag smoothly inflatable when it is inflated. CONSTITUTION: A coating part 15 of a steering wheel main unit 10, comprising a core metal part and the coating part 15, is provided with a core metal coating layer 16 and a ceiling coating layer 17 having a door part 17c of bursting a burst expected part 17a opened when inflated an air bag 31. The main unit 10 is buried with an insert 18 having a ceiling part 18g arranged in the door part 17 and a base part 18a arranged in the coating layer 16 through a connecting part having flexibility. A bottom member 20 in a lower part of a boss part B holes an air bag device 30 between the coating layer 17 and the bottom member, to arrange a connecting part 24 capable of connecting an upper end of a steering shaft 1 from the downward side, and to be connected to a spoke core metal 13 by a bolt.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steering wheel equipped with an air bag device for a vehicle, and more particularly to a steering wheel having no large parting line on the upper surface side and having improved design.

[0002]

2. Description of the Related Art A steering wheel provided with an air bag device for a vehicle has an annular ring portion and a central portion of the ring portion, as known from Japanese Patent Laid-Open No. 6-305427. A boss that connects the lower part to the upper end of the steering shaft by incorporating an airbag device in the
And a spoke portion that connects the ring portion and the boss portion.

Further, in the conventional steering wheel, the pad portion arranged on the upper side of the boss portion and holding the airbag device, the ring portion, the spoke portion, and the lower side of the boss portion are constituted, The steering wheel main body holds the pad portion.

The steering wheel main body is composed of a metal cored bar portion and a soft synthetic resin coating part, and the cored bar portion is a ring cored bar arranged on the ring part and a ring cored part arranged on the spoke part. It was composed of a spoke core metal connected to the core metal and a boss core metal arranged under the boss portion and connecting the spoke core metal. The boss core has a structure in which the steering shaft is inserted from below and the upper end of the steering shaft is fixed with a nut so that the boss can be connected to the steering shaft.

The coating portion covers the ring cored bar and the spoke cored bar from the ring cored bar side to the vicinity of the pad part.

Further, the pad portion is arranged by being screwed to the spoke core metal or the boss core metal of the steering wheel body while holding the airbag device.

[0007]

However, in the steering wheel provided with the conventional airbag device, the pad portion is arranged from the upper side of the boss portion to the steering wheel main body by using fixing means such as screws. Since it is a structure that can be mounted by being attached, it is unavoidable that a large parting line as a boundary cut between the steering wheel body and the pad portion appears on the upper surface side of the steering wheel, which deteriorates the designability of the steering wheel. It was

Further, since it is necessary to assemble the parting lines with high accuracy so that the parting line is uniform at the peripheral edge of the pad portion, strict control is required for the dimensional accuracy and assembly accuracy of each part. It was

Further, when the steering wheel is mounted on the vehicle, the steering shaft is nut-fastened to the boss core metal, but the nut-fastening is performed with the pad portion removed. Therefore, when installing the steering wheel on the vehicle, nut the steering wheel body to the steering shaft, and then
Since the pad portion is attached to the steering wheel main body, two steps of fastening the nut and attaching the pad portion are required, and it is troublesome to attach the steering wheel to the vehicle.

In order to solve the above-mentioned problems, as described in Japanese Utility Model Laid-Open No. 63-16267,
It is conceivable that the covering portion extends from the spoke portion to the upper portion of the boss portion, and further, the boss core is provided with a connecting portion capable of connecting the upper end of the steering shaft from the lower side. That is, if the covering portion is extended from the spoke portion to the upper portion of the boss portion, the parting line is eliminated on the upper surface side of the steering wheel. In addition, if the boss core is provided with a connecting portion that can connect the upper end of the steering shaft from the lower side, it can be attached to the steering shaft only on the lower surface side of the steering wheel. The steering wheel itself can be connected to.

However, in the case of the above-mentioned configuration, the steering wheel of the above publication does not have a structure in which the air bag device is disposed inside, but can be easily
The airbag device cannot be installed on the boss.

Further, in the case of disposing the airbag device, it is necessary to inflate the airbag by inflating the covering portion above the boss portion smoothly when the airbag is inflated.

The present invention has been made to solve the above-mentioned problems, improves the design of the upper surface side, and can be connected to the steering shaft as a single component in a single operation. Easy to install the device,
Moreover, it is an object of the present invention to provide a steering wheel provided with an airbag device capable of smoothly inflating the airbag when the airbag is inflated.

[0014]

A steering wheel according to the present invention includes a ring portion, a boss portion which is arranged in the center of the ring portion, has an air bag device therein, and has a lower portion connected to an upper end of a steering shaft. And a spoke portion that connects the ring portion and the boss portion, and a steering wheel including an airbag device, comprising the ring portion, the spoke portion, and the boss portion. The steering wheel main body that constitutes an upper side and a bottom member that is disposed on the lower side of the boss portion and holds the airbag device are configured, and the steering wheel main body is made of a metal cored bar portion. And a core made of a soft synthetic resin, wherein the core metal part is arranged on the ring part, and the ring core metal is arranged on the spoke part. A spoke mandrel to be connected, and the covering portion includes a mandrel covering layer covering the ring mandrel and the spoke mandrel, and the boss extending from the mandrel covering layer. And a ceiling coating layer having a door portion that is opened by breaking the surrounding planned breaking portion when the airbag of the airbag device is inflated, and the covering portion includes: The ceiling part of the ceiling cover layer embedded in the door part, the base part embedded in the core bar cover layer extending downward from the peripheral edge of the ceiling cover layer, and the hinge part when the door part is opened. And a connecting portion that connects the ceiling portion and the base portion with each other, an insert having a tensile strength higher than that of the ceiling / core metal coating layer is embedded, and the bottom member is an upper side. And holding the airbag device between the ceiling cover layer and To, the steering shaft upper end to the lower by arranging the connection portion connectable from the lower side, characterized in that it is connected to the spoke core bar by fixing means.

In this specification, the vertical direction means the direction along the axial direction of the steering shaft, and does not mean the actual vertical direction when the steering wheel is mounted on the vehicle.

[0016]

In the steering wheel according to the present invention, in addition to the core metal coating layer that covers the ring core metal and the spoke core metal, the coating portion extends from the core metal coating layer and is formed of the boss portion. Since the ceiling covering layer that covers the upper portion is provided, the parting line is eliminated on the upper surface side of the steering wheel, and the design on the upper surface side can be improved.

Further, in the steering wheel according to the present invention, since the bottom member has the connecting portion at the lower portion, which is capable of connecting the upper end of the steering shaft from below, the bottom member is attached to the steering shaft only on the lower surface side of the steering wheel. It can be connected to the steering shaft in a single step.

Further, since the airbag device is disposed and held between the ceiling covering layer on the upper side of the bottom member, the airbag device is previously disposed and held on the upper side of the bottom member. The steering wheel can be assembled by connecting the bottom member to the spoke core metal of the steering wheel body using the fixing means. At that time, at the boss portion of the steering wheel body, since only the ceiling covering layer of the covering portion is arranged and there is a space below, it is possible to appropriately dispose the airbag device in that space. As a result, the airbag device can be easily arranged.

Further, the ceiling covering layer of the covering portion is provided with a door portion which is opened by breaking the peripheral portion to be broken when the airbag in the airbag device is inflated, and the covering portion made of soft synthetic resin is provided on the covering portion. A ceiling portion embedded in the door portion of the ceiling coating layer, and a base portion that is connected to the ceiling portion by a flexible connecting portion and is embedded in a cored bar coating layer extending downward from a peripheral edge of the ceiling coating layer. And, the insert having a tensile strength higher than that of the ceiling / core metal coating layer is embedded.

Therefore, when the air bag of the air bag device is inflated, when the door portion of the ceiling covering layer is pushed by the air bag and the portion to be broken is broken and opened, the door portion is buried in the core metal covering layer. Since the ceiling portion of the insert extending from the base portion via the connecting portion is buried, the door portion can be smoothly opened and the airbag can be greatly inflated without scattering. Since the insert has a higher tensile strength than the cored bar / ceiling covering layer, even if a large tensile force is applied when the door is opened, it can be countered with sufficient strength.

Therefore, in the steering wheel according to the present invention, the design on the upper surface side can be improved and
It can be connected to the steering shaft as one component in one operation, the airbag device can be easily arranged, and the airbag can be smoothly inflated when the airbag is inflated. it can.

[0022]

An embodiment of the present invention will be described below with reference to the drawings.

The steering wheel W of the embodiment is shown in FIG.
-As shown in 7, an annular ring portion R and a ring portion R
It is configured to have a boss portion B arranged at the center of the lower portion and connecting the lower portion to the upper end of the steering shaft 1, and four spoke portions S connecting the ring portion R and the boss portion B.

Further, the steering wheel W
2, 4, and 7, the steering wheel body 10 that constitutes the ring portion R, the spoke portion S, and the upper side of the boss portion B, and the bottom portion that is arranged on the lower side of the boss portion B The material 20 and the airbag device 30 held by the bottom member 20 are provided.

The steering wheel body 10 is composed of a metal cored bar 11 and a soft synthetic resin cover 15.

As shown in FIGS. 1, 2, 4, and 6, the cored bar portion 11 is arranged on the ring part R and the ring cored bar 12 arranged on each spoke part S and connected to the ring cored bar 12. And a spoke core metal 13 that is provided. In the case of the embodiment, the ring core metal 12 is formed of a steel pipe, and each spoke core metal 13 is formed of a lightweight die-cast metal such as an aluminum alloy.
Wrap 2 and be connected to the ring core 12.
Further, each spoke core metal 13 is formed so as to extend obliquely downward from the ring core metal 12 side and has a mounting hole 13 at the lower end.
A horizontal plate portion 13a forming b is formed. Mounting hole 1
A female screw is threaded on 3b. Reference numeral 14 shown in FIG. 6 is a reinforcing rod that connects the spoke cores 13 to reinforce each spoke core 13.

The covering portion 15 is made of soft urethane, and as shown in FIGS. 1, 2, and 4, a core metal coating layer 16 for coating the ring core metal 12 and each spoke core metal 13, and a core metal coating. And a ceiling coating layer 17 that extends from the layer 16 and covers the upper portion of the boss portion B.

The ceiling coating layer 17 does not reduce the height of the upper surface side even at the portion where the cored bar coating layer 16 covering the ring cored bar 12 and each spoke cored bar 13 covers each spoke cored bar 13. Is extended to the upper surface and is formed so as to be connected to the upper surface. Therefore, below the ceiling coating layer 17, a rectangular columnar storage recess 19 surrounded by the cored bar coating layer 16 is formed.
Are formed.

Further, the ceiling covering layer 17 is provided with two rectangular plate-shaped door portions 17b and 17c that open like a double door when the airbag 31 of the airbag device 30 to be described later is inflated. When the airbag 31 is inflated, the periphery of the 17c is broken so as to quickly open the doors 17b and 17c by breaking the peripheries of the doors 17b and 17c and to greatly inflate the airbag 31. Expected break 17
a is formed. The to-be-broken portion 17a is formed in an H shape when viewed from above, and the portion where the to-be-broken portion 17a is not formed is the hinge portion 1 of the door portions 17b and 17c.
7d. Further, a plurality of pressing ribs 17e capable of pressing the membrane switch 40 described later are provided at predetermined positions on the lower surface of the one door portion 17c.

The covering portion 15 has a structure shown in FIGS.
6, the door portions 17b and 17c of the ceiling covering layer 17
The net-shaped ceiling portions 18f and 18g embedded in the base, the substantially square cylindrical base portion 18a embedded in the cored bar coating layer 16 extending downward from the peripheral edge of the ceiling coating layer 17, and the hinge portions 1
It is embedded in 7d, has flexibility, and has ceiling parts 18f and 18g.
An insert 18 composed of connecting portions 18d and 18e that connect the base portion 18a with the base portion 18a is embedded. The insert 18 is integrally formed from a synthetic resin such as an olefin-based / styrene-based / polyester-based thermoplastic elastomer having a higher tensile strength than the ceiling / core metal coating layers 17 and 16. The connecting portions 18d and 18e are the base 1
The thickness is thinner than that of 8a to ensure flexibility, and the thickness is formed so as to withstand the tensile force when the doors 17b and 17c are opened due to the inflation of the airbag 31.

The base portion 18a of the insert 18 has a mounting hole 18 for screwing the lower cover 50 to the inner peripheral surface side.
Four mounting bosses 18b in which c are arranged are formed. In addition, a plurality of mounting projections 1 for fixing the support plate 35 for disposing the membrane switch 40 as a horn switch at a predetermined position on one ceiling portion 18g.
8i is provided so as to project from the lower surface of the door portion 17c of the ceiling covering layer 17.

The support plate 35 is fixed to the ceiling portion 18g by inserting the mounting projections 18i into the mounting holes 38 provided at predetermined positions of the supporting plate 35 and heating and melting the lower ends of the mounting projections 18i. Then, it is fixed by so-called heat staking in which it is swollen and fixed.

The supporting plate 35 is formed of a thermoplastic elastomer such as olefin series, styrene series, polyester series, etc., which is more rigid than the insert 18, or a synthetic resin such as polypropylene, and as shown in FIGS.
A space regulating projection 36 that defines the horn stroke is projected on the outer peripheral edge of a, and a plurality of mounting holes 38 into which the mounting projections 18i of the insert 18 are inserted are provided in the vicinity thereof. The recess 37, which is not provided with the space regulation protrusion 36, is provided with the terminals 41 a, 4 a of the membrane switch 40.
2a will be arranged.

The membrane switch 40 includes an upper plate 41 made of phosphor bronze or the like, a lower plate 42 made of stainless steel or the like, and an insulating spacer made of a large number of flexible insulating materials arranged between the plates 41, 42. Four
3 and, each plate 41, 42,
Terminals 41a and 42a are provided at predetermined positions so as to project. Connection plates 47 and 48 made of a conductive material are fixed to these terminals 41a and 42a by rivets 45,
It will be connected to the positive electrode side and the negative electrode side of the horn operation circuit of the vehicle.

The outer shape of the membrane switch 40 is
Protective film that covers the plates 41 and 42 (figure not shown)
With the exception of the terminals 41a and 42a, the upper surface 35a of the support plate 35 has a planar shape corresponding to the inside of the mounting hole 38. Further, the spacers 43 are regularly arranged between the plates 41 and 42 at equal intervals, and when the switch 40 is assembled to the ceiling portion 18g,
The pressing ribs 17e provided on the door portion 17c of the ceiling covering layer 17 are arranged on the upper plate 41 between the spacers 43. As a result, in the embodiment, no matter which area of the door portion 17c within the outer shape range of the switch 40 is pressed, the rib 17e always presses between the spacers 43, so that the load uniformity during operation can be ensured. Becomes

As shown in FIGS. 2, 4, and 7, the bottom member 20 is formed of a lightweight and ductile die-cast metal such as an aluminum alloy, and has a central base portion 21 and a base portion 2.
1 and a plastically deformable connecting ring portion 23 that connects the base portion 21 and the connecting ring portion 23 with each other.
The book deforming section 22 is provided.

In the connecting ring portion 23, the attachment hole 1 of each spoke core bar 13 is provided in the extension of the connecting portion with each deforming portion 22.
A mounting hole 23a into which a bolt 27 as a fixing means is inserted is formed at a position corresponding to 3b. Further, an airbag device 30 described later is provided at a predetermined position of the connecting ring portion 23.
Four holding holes 23b through which the bolts 32d extending from the inflator 32 are inserted are formed.

On the lower surface of the base portion 21, there is provided a connecting portion 24 which can connect the steering shaft 1 from below. The connecting portion 24 is a split sleeve portion 2.
5 and a lock pin 26.

The lock pin 26 includes a head 26a and a head 2
6a, and a shaft portion 26b extending from 6a, and a male screw portion 26c having a male screw threaded thereon is formed at the tip of the shaft portion 26b.

The split sleeve portion 25 is provided with a serration 25b corresponding to the serration 2 formed on the upper end of the steering shaft 1 on the inner peripheral surface thereof, and an opening portion 25c formed in a part of the peripheral wall in the axial direction. 25a
And flange portions 25d and 25f that project outward from the peripheral edge of the opening 25c in the radial direction of the main body 25a and face each other.
It consists of and. The flange portion 25d is formed with an insertion hole 25e into which the shaft portion 26b of the lock pin 26 can be inserted, and the flange portion 25f is formed with a screw hole 25g into which the male screw portion 26c of the lock pin 26 can be screwed. .

To connect the steering shaft 1 to the connecting portion 24, the upper end of the steering shaft 1 is inserted into the main body 25a of the split sleeve portion 25 with the lock pin 26 removed, and the lock pin is passed through the insertion hole 25e. By screwing the male screw portion 26c of 26 into the screw hole 25g,
The diameter of the main body 25a is reduced, and the shaft portion 26b of the lock pin 26 is fitted into the groove 3 at the upper end of the steering shaft 1 to connect the connecting portion 24 to the upper end of the steering shaft 1.

As shown in FIGS. 2, 4, and 7, the airbag device 30 includes a folded bag-shaped airbag 31, and an inflator 3 for supplying inflation gas to the airbag 31.
2 and four bolts 3 configured to extend downward
It is held by the bottom member 20 by utilizing the flange portion 32c of the inflator 32 having 2d.

An opening 31a for allowing gas from the inflator 32 to flow in is opened in the lower portion of the airbag 31, and an insertion hole 31b for inserting the bolt 32d is formed in the periphery of the opening 31a.

The inflator 32 is provided with a columnar main body 32a having a gas discharge port 32b on the upper portion thereof.
An annular flange portion 32c is formed on the outer peripheral surface of the
Four bolts 3 protruding downward are provided on the flange portion 32c.
2d is fixed.

In the airbag device 30, the inflator 32 is arranged in the airbag 31, and the bolts 32d are inserted through the insertion hole 31b of the airbag 31 and the holding hole 23b of the bottom member connecting ring portion 23. The nut 33 holds the bottom member 20.

In the manufacture of the steering wheel W of the embodiment, first, the core metal part 11 and the insert 18 are set in a predetermined molding die, and the covering part 15 is formed by injection molding to manufacture the steering wheel body 10. . Further, as described above, the airbag device 30 is held on the bottom member 20 by using the bolt 32d and the nut 33 of the inflator 32. In addition, the inflator 32 is attached to the airbag 3
The airbag 31 is folded into a predetermined shape when the bolts 32d are inserted into the inner casing 1 and the bolts 32d are projected from the insertion holes 31b.

Then, the support plate 35 having the membrane switch 40 mounted on the upper surface thereof is arranged on the lower surface of the insert ceiling portion 18g of the steering wheel body 10,
Each of the mounting protrusions 18i is inserted into the mounting hole 38 and caulked, and the membrane switch 40 is mounted on the steering wheel body 10. The connection plates 47 and 48 are previously fixed to the membrane switch 40 with the rivets 45.

Then, the mounting holes 23a of the bottom member 20 holding the airbag device 30 are aligned with the mounting holes 13b of the steering wheel body 10, and the bolts 27 as fixing means are mounted through the mounting holes 23a. The lower cover 50 is screwed into the hole 13b to attach the lower cover 50 to the mounting boss 1 of the insert 18.
The steering wheel W can be manufactured by screwing to 8b.

Further, when the steering wheel W is connected to the steering shaft 1, the lock pin 2
The upper end of the steering shaft 1 is inserted into the main body 25a of the cracked sleeve portion 25 with 6 removed, and the insertion hole 2
5e, the male screw portion 26c of the lock pin 26 is screwed into the screw hole 2
By screwing with 5g, the diameter of the main body 25a is reduced, and the shaft portion 26b of the lock pin 26 is fitted into the groove 3 at the upper end of the steering shaft 1 to connect the steering wheel W to the steering shaft 1. Can be made.

In the steering wheel W of the embodiment, the covering portion 15 extends from the mandrel covering layer 16 in addition to the mandrel covering layer 16 covering the ring mandrel 12 and the spoke mandrel 13, and the boss portion. Since the ceiling covering layer 17 that covers the upper portion of B is provided, the parting line is eliminated on the upper surface side of the steering wheel W, and the design on the upper surface side can be improved.

Further, since the bottom member 20 has the connecting portion 24 which can connect the upper end of the steering shaft 1 from the lower side to the lower portion, it can be attached to the steering shaft 1 only on the lower surface side of the steering wheel W. Therefore, the steering wheel W can be connected to the steering shaft 1 in one step.

Further, the airbag device 30 includes the bottom member 2
Since it is arranged and held between the ceiling covering layer 17 on the upper side of 0, the airbag device 30 is arranged and held on the upper side of the bottom member 20 in advance, and the bottom portion is formed by using the bolt 27. The steering wheel W can be assembled by connecting the material 20 to the spoke core metal 13 of the steering wheel body 10. At that time, the portion of the boss portion B of the steering wheel body 10 is covered with the covering portion 15
Since only the ceiling covering layer 17 is provided, the space as the storage recess 19 is provided below, so that the airbag device 30 can be appropriately disposed in the space. Will be easier.

Further, the ceiling covering layer 1 of the covering portion 15
7, the door portion 17b, which is opened by breaking the peripheral planned breakage portion 17a when the airbag 31 of the airbag device 30 is inflated.
17c is provided, and furthermore, the soft urethane coating portion 15 has net-shaped ceiling portions 18f and 18g embedded in the door portions 17b and 17c of the ceiling coating layer 17, and the ceiling portion 18f and 1.
8 g and a base portion 18 a that is connected to the flexible metal connecting portions 18 d and 18 e and that is embedded in the core metal coating layer 16 that extends downward from the peripheral edge of the ceiling coating layer 17, An insert 18 having a tensile strength is embedded from the covering layers 17 and 16.

Therefore, when the airbag 31 of the airbag device 30 is inflated, the door portions 17b and 17c of the ceiling covering layer 17 are formed.
Is pushed by the airbag 31 to rupture and open the to-be-broken portion 17a, the door portions 17b and 17c are provided with inserts 18 extending from the base portion 18a embedded in the core metal coating layer 16 through the connecting portions 18d and 18e. Since the ceiling portions 18f and 18g are buried, the door portion 1 does not scatter smoothly.
The airbag 31 can be greatly inflated by opening 7b and 17c. The connecting portion 1 of the insert 18
Since 8d and 18e have a tensile strength higher than that of the cored bar / ceiling covering layers 16 and 17, even if a tensile force acts when the doors 17b and 17c are opened, they can be countered with sufficient strength,
It is possible to obtain the same effects as those described in the section of the action and effect of the invention described above. In particular, when the covering portion 15 is made of soft urethane as in the example, since it has elasticity and low tensile strength as compared with soft synthetic resin materials such as thermoplastic elastomers such as polyolefin-based or styrene-based, The breaking line at the time of breaking may be formed to extend beyond the planned breaking portion 17a, but the breaking line may be formed on the ceiling portions 18f and 18g and the connecting portion 1.
Since 8d and 18e can be regulated, scattering of the door portions 17b and 17c can be effectively prevented.

When the door 17c is opened, the terminals 41a and 42a of the membrane switch 40 are bent so that the support plate 35 and the membrane switch 40 move together.

Further, in the steering wheel W of the embodiment, since the airbag device 30 is attached to the bottom member 20 by the bolt 32d provided on the flange portion 32c of the inflator 32, the airbag device 30 is mounted on the airbag 31. And the inflator 32, the number of constituent parts of the airbag device 30 can be reduced, and the number of manufacturing steps and manufacturing cost of the steering wheel W can be reduced.

Further, the steering wheel W of the embodiment
Since the bottom member 20 that holds the airbag device 30 is provided with the plastically deformable deformation portion 22, when the airbag device 30 is not in operation after being mounted on the vehicle,
Even if an impact force acts on the ring portion R, the deforming portion 22 is plastically deformed, and the ring portion surface formed by the ring portion R can be oriented in a direction orthogonal to the acting direction of the impact force. Can be received by the surface of the ring portion having a large area, and the impact force can be mitigated.

Further, in the steering wheel W of the embodiment, the membrane switch 40 as a horn switch is arranged on the upper surface 35a of the supporting plate 35 having rigidity at a position surrounded by the interval regulating projections 36. Therefore, it is possible to prevent the switch 40 from being turned on even when the pressing force for the folded airbag 31 to restore is applied upward. Furthermore, since the membrane switch 40 is arranged between the lower surface side of the door portion 17c and the upper surface 35a of the support plate 35 having a predetermined distance by the distance regulating projection 36, the switch 4
It is easy to secure a constant distance between the support plate 35 having rigidity of the portion where 0 is arranged and the door portion 17c, and the switch 4
An operation stroke of 0 can be easily maintained constant. Further, the upper plate 4 between the spacers 43
Since the pressing ribs 17e of the door portion 17c are arranged on the upper portion of the switch 40, no matter which area of the door portion 17c within the outer shape range of the switch 40 is pressed, the ribs 17e are always provided between the spacers 43. Pressing makes it possible to ensure the uniformity of the load during operation.

In the steering wheel W of the embodiment, the bolt 27 is used as the fixing means for attaching the bottom member 20 to the steering wheel body 10, but a rivet may be used.

In the embodiment, the lock pin 26 fitted into the groove 3 of the steering shaft 1 is used as the connecting portion 24 connected to the steering shaft 1. However, the connecting portion 24 is a steering wheel. Shaft 1
Any structure may be used so that the upper end of the above can be connected from the lower side. In addition, it is described in JP-A-63-134368, JP-B-2-25691, JP-B-5-2488 and the like. As described above, a structure may be adopted in which a mounting plate, a screw member, or the like is provided on the steering shaft side and bolted or screwed to these.

[Brief description of drawings]

FIG. 1 is a plan view of a steering wheel according to an embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view of the same example, showing a II-II portion in FIG. .

FIG. 3 is a partially enlarged view of FIG.

4 is a cross-sectional view of the same example, showing a IV-IV site in FIG. 1. FIG.

FIG. 5 is a partially enlarged view of FIG.

FIG. 6 is an exploded perspective view of the steering wheel body of the embodiment.

FIG. 7 is an exploded perspective view of the same embodiment.

FIG. 8 is a perspective view of a support plate and a membrane switch used in the same embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Steering shaft, 10 ... Steering wheel main body, 11 ... Core metal part, 12 ... Ring core metal, 13 ... Spoke core metal, 15 ... Coating part, 16 ... Core metal coating layer, 17 ... Ceiling coating layer, 17a ... Breakage Scheduled portion, 17b / 17c ... Door portion, 17d ... Hinge portion, 18 ... Insert, 18a ... Base portion, 18d / 18e ... Connecting portion, 18f / 18g ... Ceiling portion, 20 ... Bottom member, 24 ... Connecting portion, 27 ... ( Fixing means) Bolt, 30 ... Air bag device, 31 ... Air bag, 32 ... Inflator, R ... Ring portion, B ... Boss portion, S ... Spoke portion, W ... Steering wheel.

Claims (1)

[Claims] 1. A ring portion, a boss portion arranged in the center of the ring portion and having an air bag device built therein, and a lower portion connected to an upper end of a steering shaft, and the ring portion and the boss portion are connected to each other. A steering wheel body including an airbag device configured to include a spoke portion, a steering wheel body that configures the ring portion, the spoke portion, and an upper side of the boss portion; A bottom member that is arranged on the lower side of the boss portion and holds the airbag device; and the steering wheel body is composed of a metal cored bar and a soft synthetic resin coating. The core metal part includes a ring core metal arranged in the ring part, and a spoke core metal arranged in the spoke part and connected to the ring core metal, The coating portion covers the ring cored bar and the spoke cored bar, and a cored bar coating layer that extends from the cored bar coating layer and covers the upper portion of the boss part, and And a ceiling coating layer having a door portion that is opened by breaking a peripheral planned breaking portion during expansion, wherein the coating portion includes a ceiling portion embedded in the door portion of the ceiling coating layer, and A base portion that is embedded in the core metal coating layer that extends downward from the peripheral edge of the ceiling coating layer, and is flexible by being embedded in a hinge portion when the door portion is opened, and connects the ceiling portion and the base portion. An insert having a tensile strength higher than that of the ceiling / core metal coating layer is embedded, and the bottom member disposes the airbag device with the ceiling coating layer on the upper side. Hold the upper part of the steering shaft on the lower side By placing the connectable connection section, a steering wheel with an air bag device characterized by being connected to the spoke core bar by fixing means.