Abstract:
A vehicle steering wheel ( 10 ) includes a hub ( 12 ) and an airbag module ( 26 ). The vehicle steering wheel ( 10 ) further includes a plurality of switches ( 18, 20, 22 ) being integrated in a common housing ( 16 ). The housing ( 16 ) is fitted on the airbag module ( 26 ) and includes at least one mount ( 32 ) cooperating with a cover ( 28 ) of the airbag module ( 26 ).

Description:
TECHNICAL FIELD  
       [0001]     The invention relates to a vehicle steering wheel.  
       BACKGROUND OF THE INVENTION  
       [0002]     A steering wheel normally includes a hub and several switches. The switches enable the vehicle driver to operate e.g. the gear change, the radio or a telephone without having to take the hands off the steering wheel. Hitherto, a separate switch was provided fitted to the hub for each function to be switched. This complicates assembly. Apart from this a complicated system is needed to ensure precise location of the switches since otherwise an undesirable gap between adjacent components, for example a neighboring switch or a cover of the steering wheel, may materialize.  
         [0003]     The object of the invention is to further develop a steering wheel of the aforementioned kind so that assembly and production complications are reduced.  
       BRIEF SUMMARY OF THE INVENTION  
       [0004]     According to the invention, a vehicle steering wheel comprises a hub and an airbag module. The vehicle steering wheel further comprises a plurality of switches being integrated in a common housing. The housing is fitted on the airbag module and comprises at least one mount cooperating with a cover of the air bag module. This results in only a single housing needing to be produced for the plurality of switches. The single housing is attached to the airbag module, and then this pre-mounted unit is installed in the steering wheel, thus reducing the number of components and assembly steps. Apart from this, the various switches are now precisely positioned relative to each other so that no undesirable gap can materialize between the individual switches. Moreover, the construction according to the invention results in particularly precise positioning of the cover for the air bag module relative to the switches so that no undesirable gap can materialize between the individual switches and the cover.  
         [0005]     According to a further aspect of the invention, an apparatus comprises a rotatable vehicle steering wheel having a hub member connected to a steering column and rotatable with the steering wheel; an air bag module including a cover mounted on the steering wheel; and a housing supporting a plurality of electrical switches, the housing being spaced apart from the cover, the housing being secured to, mounted on, and supported by a rigid member of the air bag module. In the preferred embodiment of the invention the housing comprises at least one mount cooperating with the cover.  
         [0006]     Preferably the mount is formed by a mounting peg engaging an opening of the cover. This results in the cover being movable relative to the switches which are fixedly secured to the steering wheel, so that they can be pressed, for example, to actuate a signal horn switch.  
         [0007]     It is preferably provided for that the housing surrounds the air bag module at least in part. This enables the switches to be arranged to advantage in the portions surrounding the air bag module available between the rim of the steering wheel and the air bag module so that a particularly compact design materializes.  
         [0008]     Preferably a plug is provided, all of the switches being connected to the plug. This plug can be fitted at a suitable location either directly on the housing or at the end of a cable ported into the housing. All switches can now be connected with minimum complication simply by inserting this sole plug into a complementary connector socket.  
         [0009]     Preferably the function of at least one of the switches is adapted to be programmed, thus enabling a standardized housing to be used with the various switches for different variants of the vehicle or vehicle fittings.  
         [0010]     In accordance with the preferred embodiment of the invention it is provided for that one of the switches serves to activate a hazard warning flasher. This switch is provided in a central position for optimum accessibility so that the hazard warning flasher can be activated, if required, without delay and without having to take the hands off the steering wheel. In addition, it may be provided for that the hazard warning flasher is activated automatically and electromechanically on activation of the air bag module or by the activation electronics of the air bag module.  
         [0011]     Advantageous aspects of the invention will be apparent from the sub-claims. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]      FIG. 1  is a diagrammatic plan view of a steering wheel;  
         [0013]      FIG. 2  is a diagrammatic sectional view taken along the plane II-II as shown in  FIG. 1 ;  
         [0014]      FIG. 3  is a view in perspective of a housing including switches as used on the steering wheel as shown in  FIG. 1 ; and  
         [0015]      FIG. 4  is a sectional view of a steering wheel in accordance with the invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0016]     Referring now to  FIG. 1  there is illustrated a vehicle steering wheel  10  comprising a hub  12  and a rim  14 . Attached to the hub  12  is a housing  16  (see also  FIGS. 2 and 3 ) in which several switches  18 ,  20 ,  22  are accommodated. The housing  16  is provided, for the purpose of being fitted to or positioned on the hub  12 , with several locating pegs  24  engaging corresponding holes  25  in the hub.  
         [0017]     The housing  16  is configured U-shaped (see  FIG. 3 ) in general, i.e. it surrounding a center space by approximately 180°. Mounted in this center space is an air bag module  26  indicated diagrammatically. On the side of the air bag module  26  facing the vehicle driver, a cover  28  is mounted forming a more or less flush finish with the switches  18 ,  20 ,  22 , to ensure enhanced visual appeal as a whole.  
         [0018]     For fitting or positioning the cover  28  it is provided with several openings  30 , each of which is engaged by a mounting peg  32  fitted to the housing  16 . The mounting peg  32  together with the openings  30  enable the cover  28  to be depressed in a direction parallel to the axis of rotation of the steering wheel for actuating the signal horn, for example.  
         [0019]     In this configuration, the housing  16  together with the locating pegs  24  which cooperate with the hub  12 , and with the mounting pegs  32  which cooperate with the cover, simultaneously serves to locate and guide the cover  28  relative to the partly adjoining hub  12 .  
         [0020]     Since the cover  28  is directly fitted to the housing  16  of the switches, the gaps between the cover and the switches are minimized, despite the cover being shiftable. Similar minimized gaps result between the switches and the hub of the steering wheel, since the housing of the switches is securely fitted to or positioned on the hub.  
         [0021]     Circuit boards and other connecting elements for the various switches  18 ,  20 ,  22  may be arranged in the housing  16 , including also electronics components, so that the function of the switches can be freely programmed. For this purpose a programming terminal  34  is provided which is accessible from the rear in the fitted steering wheel. In this way it is possible to provide for an individual, customized switch circuiting for one and the same vehicle type. Only a sole plug is provided for connecting all switches by it being simply inserted in a complementary connector socket on assembly of the vehicle steering wheel.  
         [0022]     In accordance with the invention it is be provided for that several switches are mounted on the air bag module  26  instead of on the hub  12 . An example embodiment in accordance with the invention is described with reference to  FIG. 4 . The components that have already been described with reference to FIG  1  to  3  have the same reference numerals.  
         [0023]     The air bag module  26  shown in  FIG. 4  includes, inter alia, a rigid carrier plate  36 . A “floating” part of the module  26  is mounted on the carrier plate  36  so as to be movable in an axial direction in order to close a horn contact. The carrier plate  36  has a flange portion  38  resting on a shoulder of the hub  12  in the installed state of the air bag module  26 . The flange portion  38  of the carrier plate  36  also supports the housing  16  of the switches  16 ,  18  or  20 , i.e. the housing  16  is mounted and secured on the flange portion  38  of the carrier plate  36 .  
         [0024]     When the air bag module  26  is installed it is lowered into the hub  12  until the flange portion  38  of the carrier plate  36 , which supports the housing  16  of the switches and the floating part of the air bag module  26 , rests on the shoulder of the hub  12 .