MXPA98001445A - Modular combination of steering wheel and bag - Google Patents

Abstract

The present invention relates to a combined modular unit of steering wheel and air bag is finally assembled. A cover is first molded around an insert of the steering wheel. The cover is molded with a single piece above the wheel and the area where the airbag module will be placed. In the past, two separate covers were used, since the airbag was usually fixed to the steering wheel after the steering wheel had been fixed to the vehicle. The modular unit is then fixed from the side to the arrow of the steering tube of the vehicle. The present invention results in increased flexibility at the site where the manufacturing steps take place, and improves the aesthetic appearance of the cover for the steering wheel and the airbag.

Description

"MODULAR COMBINATION OF STEERING WHEEL AND AIR BAG" BACKGROUND OF THE INVENTION This invention relates to a combined flywheel and airbag having a one-piece coating that is affixed to the steering tube of the vehicle after being assembled as a modular unit. Modern vehicles typically come equipped with an airbag mounted on the steering wheel of the vehicle. The incorporation of the airbag in the steering wheel of the vehicle has required many changes in the design, manufacture and assembly of the steering wheel. As an example, airbags typically include a cover that is separate from the steering wheel cover. The airbag cover is blown out of the steering wheel when the air bag deploys. Airbags are often manufactured by a manufacturer other than the steering wheel. An effort was made so that the cover of the airbag and the cover of the steering wheel were of identical color and texture, unfortunately sometimes there have been some differences in the two covers.

The steering wheels of the vehicle are typically assembled by initially connecting a portion of the steering wheel to the steering tube. The airbag is then assembled on the steering wheel and the air bag cover is then placed on the steering wheel enclosing the airbag. This method of dressing of the prior art has required that there be numerous flame-retardant and threaded pieces in the vehicle assembly line. There is a desire to reduce the number of steps that occur in the final vehicle assembly line and therefore a combined steering wheel and air bag that can be assembled as a modular unit in the vehicle would be desirable. In the prior art, the steering wheel was necessarily attached to the steering tube first. Once the airbag is assembled, there is no access to the fastening bolts that fix the flywheel in the steering tube. Therefore, the handwheel is initially fixed, the air bag module preventing the airbag cover then being fixed. The required sequence of these manufacturing steps undesirably limits the flexibility of manufacturing processing.

COMPENDIUM OF THE INVENTION In an embodiment of this invention disclosed, the steering wheel and air bag are designed as a modular unit. The assembled modular unit is then attached to the steering tube. The disclosed fastening methods allow the modular combination unit to be attached to the steering tube even after the airbag has been fixed to the steering wheel. In a disclosed embodiment, the modular unit is connected to the steering tube by a bolt accessible from the outside of the steering tube. The bolt has a bevelled gear head and a tool is inserted from the side to drive the bolt and hold the modular unit in the steering tube. In a second embodiment, the combined modular unit is placed in the steering tube and a rotating nut is rotated to bring the modular unit down to the steering tube. Eventually, the structure in the steering tube is drawn into a tight fitting relationship with the plug of the modular unit. The modular unit is thus held in the steering tube.

In addition, since a combined modular airbag and steering wheel unit is achieved, a single cover can be used. The single cover through both the air bag and the steering wheel eliminates problems with different colors or textures to optimize the fit and finish. In a preferred embodiment of this invention, a portion of the cover is formed to break from the remainder of the cover in the event that the air bag is deployed. In one example, the break seams are molded into the cover in such a manner that when the air bag is deployed, the cover through the air pocket is detached from the rest of the cover of the break strips. In the preferred embodiments of this invention, the cover can be molded on the flywheel through injection molding. Alternatively, the reaction molding can be used. In any case, the molded one-piece cover extends above the airbag and the flywheel. After the cover is molded, the air bag module is fixed to the steering wheel and the modular unit is then fixed to the arrow of the steering tube. These and other features of the present invention may be better understood from the following specification in drawings, of which the following is a brief description.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a detailed view of a modular airbag and steering wheel unit of the invention. Figure 2 is an assembled view of the modular unit shown in Figure 1. Figure 3 shows a first method for attaching the modular unit to the steering tube. Figure 4 shows a second method for fixing the modular unit in the steering tube. La Fuiguira 5 shows a detail of a one-piece cover of the present invention. Figure 6 is a detailed view of another embodiment within the scope of the present invention. Figure 7 is a cross-section through the embodiment of Figure 6.

DETAILED DESCRIPTION OF A PREFERRED MODALITY Figure 1 shows the components of the modular unit 20 of steering wheel and air bag. As shown, a base 22 of the steering wheel includes a plug 23 that holds the air bag. The plug 23 also has the portion fixed to the steering tube. Preferably, the plug 23 is formed of steel as a separate part and the remainder of the base 22 of the flywheel is modeled in magnesium around the plug 23. A cover 24 is integrally molded over the base 22 of the flywheel. An airbag module 26 is shown as a one-piece article even though it consists of actually several separate units. The airbag mode itself is like that known in the art and does not form any portion of this invention. In addition, the fixation of the module to the socket 23 can be effected by known methods. An internal substrate 27 provides a reaction surface adjacent to the air bag such that the switch 28 of the horn can be compressed relative to the air bag module. The substrate is preferably molded by injection of a thermoplastic and secured in the airbag module. Other types of horn switches can be incorporated in the present invention, in the structure of the horn plate does not form any portion of this invention. The cover 24 is first molded above the flywheel 22 and above the area where the module 26 of the airbag will be reed. The air bag module 26, the inner substrate 27 and the horn switch 28 are then assembled into the socket 23. Since the air bag handwheel covers are molded as a single piece, they have a uniform color and texture . This is an improvement in relation to the prior art. A rear cover 30 can be mounted on the modular unit before the modular unit is attached to the vehicle, or it can be a final assembly step after the modular unit has been attached to the vehicle steering tube. As shown in Figure 2, the modular unit 20 incorporates the internal substrate 27 reed just below the outer cover 24. The cover 24 is molded to extend above the plug 23 when modeled at the base of the steering wheel. The mold is taught to leave a space under the cover to ree the airbag module. Figure 2 is a cross-section through the plug areas of the modular unit 20. The module 26 of the air bag is reed below the sub-layer 27. The plug 23 is fixed to the steering tube 32 by a plane 34. The rear cover 30 encloses the portions of the modular unit 20. In the prior art providing access to the bolt 34 required that the steering wheel be attached to the steering tube before the air bag is fixed. This required the two separate covers.

In one aspect of this invention, the air bag can be attached to the modular unit by making the back cover extend upwardly sufficient distance such that when the back cover is not reed in the modular unit, there is a space for the module 26 of the air bag is placed inwardly from the side of the assembly in the direction shown in arrow D. In this way, the bolt 34 is initially fixed to the steering tube 32, and the air bag assembly 26 can be positioned inwardly from the side. In this way, a one-piece coating 24 can be used. More preferably, the air bag unit is fixed to the steering wheel and plug 23 before the steering wheel is attached to the steering tube. One embodiment to achieve this fixation is shown in Figure 3. As shown in Figure 3, an airbag module 26 has already been fixed adjacent the plug 23. The plug 23 receives a pin 34 having gear teeth 35 beveled A tool 36 extends inward from the side of the modular unit 20 and includes a gear drive 38. A wire guard holder 40 can hold tool 36 at an inner end. The tool 36 is rotated to rotate the gear 38. The gear 38 drives the teeth 35 of the gear at the periphery of the head of the drive pin 34. The threads 42 in the bolt 34 are received within a threaded bore in the steering tube 32, thus pulling down the modular flywheel 20 and holding the modular unit in the steering tube 32. A second embodiment of the fastening method is shown in Figure 4. As shown in Figure 4, the plug 23 includes a fixed plug portion 50 having a flange 52 which secures a rotary plug 54. The airbag module 26 is fixed with bolts 67 in the plug 23. The plug 54 has a flange 56 which prevents its movement beyond the flange 52. The rotary plug 54 includes threads 58 on the inner peripheral surface. The fixed plug 50 includes a tapered matching section 60. The flywheel 62 includes a tapered portion 64 that is to be received within the tapered mating portion 60. A threaded external portion 66 is engaged in the thread 58 and draws the module 49 down towards the flywheel 62. In this manner, the embodiment shown in Figure 4 is assembled by initiating the assembly of the flywheel and the cover in the bag module of air and other assembled parts. The combined modular unit is then attached to the steering tube. Prior to attaching the back cover a tool is placed inwardly from the side and urges the rotary plug 54 relative to the steering tube 62. The threaded portion 58 engages the threaded portion 66 and draws the modular unit down to the tube or column 62. Eventually, the tapered portions 62 are forced into the tapered coincident portion 60 and the modular unit 49 is secured in the tube of the direction 62. As shown in Figure 5, the cover 24 is molded in the flywheel 22. The portion of the coating outwardly to the air bag 26 and the internal substrate 24 includes the break seams 68. When the air bag is deployed, the cover 24 will break away from the rest of the coating at the break seams 68, allowing deployment of the air bag. The break seams can be formed as a thin portion of the cover by an appropriate structure in the mold. Figure 6 shows another embodiment wherein a rear cover half 70 replaces the entire rear cover shown in the embodiment of Figure 1. The rear half cover provides access to the plug connection with the steering tube from a larger area .

With the modalities of the full rear cover it may be necessary that the rear cover is removed, while the modular unit is being attached to the steering tube. The back cover is then fixed to the modular unit. With the rear half-cover, there may be sufficient access in such a way that the back cover can be pre-assembled in the modular unit. A different type of horn switch is shown in this mode. In addition, a different substrate 27 is also shown. As shown in Figure 7, this substrate 27 extends around a larger area of the substrate shown in Figures 1 and 2. The substrate of Figure 7 is secured in the coating instead of the airbag module. The cover 24 is preferably connected to the flywheel 22 by molding the coating around the base of the flywheel and above the area where the airbag module is received. The internal substrate can be placed on the steering wheel before molding the cover. Then, the air bag module and the horn switch are inserted under the cover and into the plug. The assembled modular unit is then connected to a steering tube.

The molded coating is preferably an injection molding of a plastic or it could be the reaction molding of a foam material such as urethane. The materials known as are currently used for the steering wheel covers and the airbag can of course be used. If a foam material is used, some design consideration must be provided to provide sufficient support in the area of the air bag. Due to this reason, the substrate shown in Figure 7 can be used. Finally, the invention disclosed in the application presents several basic ideas of the invention. The details to date of those concepts are disclosed in a North American Patent Application entitled "Modular Steering Wheel and Air Bag Combination ", Serial Number, presented, and that belongs to the concessionaire of this application A preferred embodiment of this invention has been disclosed, however, an operator skilled in the art will recognize that certain modifications are within the scope of this invention For that reason, the following claims should be studied in order to determine the true scope and content of this invention.

Claims (20)

R E I V I N D I C A C I O N S

1. A method for connecting a steering wheel and an airbag in a steering tube of the vehicle comprising the steps of: (a) connecting the airbag module with a steering wheel to form a modular unit; and (b) then connecting the air bag module and the steering wheel combined in a tube of the vehicle direction.

2. A method according to claim 1, wherein a cover is formed to cover both the airbag module and the flywheel before step (b).

3. A method according to claim 2, wherein the cover is formed with a break seam in an area where the cover must break away to allow deployment of the air pocket. .

A method according to claim 1, wherein the modular unit is connected to the steering tube by a first rotating member that rotates relative to both the steering tube and the modular unit.

5. A method according to claim 4, wherein the first rotating member is a bolt having gear teeth that engage the gear teeth in a second rotary member, the second rotary member rotates to rotate the gear teeth and drive the gear teeth. bolt to secure the modular unit in the steering tube.

6. A method according to claim 5, wherein the second rotary member is a tool that couples the bevel gear teeth to a bolt head.

7. A method according to claim 4, wherein the first rotating member is an internally threaded nut that is received in an externally threaded portion of the steering tube, the nut is rotated relative to the modular unit and relative to the to the steering tube to be tightened on the externally threaded portion of the steering tube and to secure the modular unit on the steering tube.

8. A modular set of steering wheel and air bag comprising: a steering wheel having a portion of the steering wheel to be fastened for operation of a vehicle and a portion of the plug for fixing the steering wheel in a steering tube of a vehicle; an airbag module, the airbag module is received on the flywheel and on an opposite side of the plug from the steering tube; and a one-piece cover, covering at least the wheel portion of the steering wheel and the air bag module, the one-piece cover covers one side of the air bag module remote from the plug.

A modular unit according to claim 8, wherein the one-piece cover is formed with a structure to bring the cover to break in a location where the airbag module is received when the module is deployed of the air bag.

A modular unit according to claim 9, wherein the cover is molded of a plastic material around the flywheel.

A modular unit according to claim 8, wherein the plug is adapted to be fixed to a steering tube by means of a threaded bolt, and the threaded bolt is formed with gear teeth that can be coupled by a rotating world to Push the threaded pin and secure the plug in the steering tube.

12. A modular unit according to claim 11, wherein the rotary member is a tool inserted adjacent to the bolt, and the bolt is formed with beveled gear teeth for coupling the rotary member.

A modular unit according to claim 8, wherein the plug is connected to a rotating internally threaded member that rotates relative to the plug, the internally threaded member is adapted to be secured in an externally threaded portion of the steering tube for Secure the plug in the steering tube.

A method for forming a combined modular handwheel and airbag unit comprising: (a) providing a handwheel including a generally circular wheel portion to be held by the operator operating the vehicle; (b) providing an air bag module; (c) molding a coating on top of an area of the steering wheel where the air bag module is to be fixed and also through at least a portion of the wheel of the steering wheel such that the one piece covering covers both components; and (d) then fix the airbag module in the area on the steering wheel.

15. A method according to claim 14, wherein the modular unit is attached to the steering tube in a vehicle after passage (d).

16. A modular combined set of steering wheel and airbag comprising: a steering wheel including a wheel portion to be secured by an operator to operate the vehicle and a plug portion to secure the steering wheel to the steering tube of a vehicle; an airbag module secured in the steering wheel; a fixing structure for fixing the steering wheel plug in a steering tube of a vehicle with the airbag module already fixed to the steering wheel.

A modular unit according to claim 16, wherein the fixing structure includes a bolt extending through the plug, the bolt is urged towards the threaded portion of the steering tube to secure the steering wheel to the arrow of the Steering tube.

18. An apparatus according to claim 17, wherein the bolt includes gear teeth that are selectively engageable with the second rotary member to rotate the gear teeth and drive the bolt toward the arrow of the steering tube.

19. A modular unit according to claim 18, wherein the gear teeth are beveled gear teeth formed in a head of the pin, and the second member is a tool inserted adjacent the pin to rotate the gear teeth. A modular unit according to claim 16, wherein the fixing structure includes an internally threaded rotary member that rotates relative to the plug portion of the flywheel, the internally threaded member is rotatably adapted to be received in a portion externally threaded shaft of the steering tube for a vehicle.