Abstract:
To provide a steering wheel and an airbag apparatus including a module cover, a portion thereof is operable to prevent an interior of the airbag apparatus from being viewed through a gap between the module cover and a spoke of the steering wheel. A projecting strip extending from an occupant side of a lower spoke of a steering wheel is configured to face the gap between the occupant side of the spoke and a lower rim of the module cover extending from the rear of the module cover.

Description:
BACKGROUND OF THE INVENTION 
   The present invention relates to vehicular steering wheels, and in particular, to a steering wheel with a centrally disposed airbag apparatus for restraining an occupant. 
   Steering wheels with an airbag apparatus are sometimes known to have a cover for preventing the interior of the airbag apparatus from being viewed through a gap between a module cover of the airbag apparatus and spokes that may comprise the steering wheel. 
     FIG. 4  is a perspective view of a module cover disclosed in Japanese Unexamined Patent Application Publication No. 2000-25548. The module cover  60  has a downward portion  62  projected from a lower spoke engaging portion  61  that points down, i.e., in a so called six o&#39;clock position, when the steering wheel is in a position to direct a vehicle straight ahead. The downward portion  62  functions as a concealer, preventing the interior of the airbag apparatus from being viewed. 
   The airbag apparatus disclosed above is of a type in which the upper surface of the module cover connects to the upper surface of the spoke. Therefore, the concealing structure cannot be applied to a steering wheel and airbag apparatus as disclosed in Japanese Patent Application Publication No. 2003-118526, in which an airbag apparatus projects from the spoke toward the occupant without a cover. 
   To perform a concealing function, Japanese Patent Application Publication No. 2003-118526 discloses a separate cover mounted around the outer periphery of a module cover. The assembly and installation of this design is time and labor intensive. Furthermore, the cover and module cover lack a sense of unity and aesthetic appeal. 
   Accordingly, it is an object of the present invention to provide a steering wheel with an airbag apparatus in which the interior of the airbag apparatus is prevented from being viewed through the gap between a module cover and a spoke even if the module cover is disposed in such a manner as to project from the spoke, and which is easy to manufacture. 
   SUMMARY OF THE INVENTION 
   A steering wheel with an airbag apparatus according to the present invention includes an airbag apparatus disposed substantially in the center of the steering wheel, the steering wheel comprising spokes. The airbag apparatus includes a module cover operable to conceal the interior of the airbag apparatus and further comprises an outer periphery that covers the spokes. In addition, a concealer is disposed at the gap between the outer periphery of the module cover and the surface of the spoke adjacent to an occupant. 
   The concealer is constructed of a projecting strip disposed at a surface of a spoke adjacent to the occupant and an outer rim of the module cover. Further, the outer rim of the module cover is disposed close to a side of the projecting strip that is adjacent to the outer periphery of the steering wheel. 
   Another aspect includes the concealer disposed at the gap between a downward spoke of the steering wheel and the module cover at a position wherein the steering wheel is operable to guide the vehicle comprising the apparatus straight ahead. 
   A further aspect of the invention has a concealer constructed of a projecting strip disposed on the occupant side of the spokes and the outer rim of the module cover disposed close to the side of the projecting strip adjacent to the outer periphery of the module cover. 
   The concealer is operable to prevent the interior of the airbag apparatus from being viewed. This structure eliminates the need for mounting a separate blind cover to the module cover, facilitating manufacture, and providing an aesthetic appearance. 
   Another aspect of the present invention includes a horn switch, disposed at or in the vicinity of the spokes that can be prevented from being viewed. 
   It is particularly preferable to dispose the concealer at a spoke in the so called six o&#39;clock position. The steering wheel and airbag apparatus of the present invention prevent the interior of the airbag apparatus from being viewed not only when a spoke is in a six o&#39;clock position, but also when the steering wheel is turned approximately 90 degrees to a three o&#39;clock or nine o&#39;clock position. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of a steering wheel with an airbag apparatus according to an embodiment of the invention. 
       FIG. 2  is a longitudinal sectional view of the steering wheel with an airbag apparatus of  FIG. 1 . 
       FIG. 3  is an exploded perspective view of the steering wheel with an airbag apparatus of  FIG. 1 . 
       FIG. 4  is a perspective view of a module cover according to a related art. 
   

   DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
   An embodiment of the present invention will be described hereinbelow with reference to the drawings. 
     FIG. 1  is a perspective view of a steering wheel  1  with an airbag apparatus according to the invention, with the airbag removed.  FIG. 2  is a longitudinal sectional view of the steering wheel  1  with an airbag apparatus  10  (taken along line  2 - 2  of  FIG. 1 ).  FIG. 3  is an exploded perspective view of the steering wheel  1  and airbag apparatus  10 . 
   The vertical direction and the lateral direction in the following description indicate those in a steering wheel plane when viewed from the occupant, wherein the steering wheel  1  is in a position in which a vehicle housing the steering wheel and airbag apparatus is driving straight ahead. Front-back positions indicate the directions relative to the steering wheel. 
     FIG. 1  illustrates a steering wheel  1  of what is called a three-spoke type and includes spokes  3 L,  3 R, and  3 D extending from a substantially central steering base  2  in three directions, to the right and left (in the directions of so called three o&#39;clock and nine o&#39;clock) and downward (in the direction of six o&#39;clock). The distal ends of the spokes  3 L,  3 R, and  3 D connect to a ring  4  around an outer periphery of the steering wheel  1 . The steering base  2  may be joined to the distal end of a steering shaft (not shown). A back cover  5  may be mounted in such a manner as to cover the steering base  2  from the back (from the side opposite to the occupant). 
     FIG. 2  illustrates an airbag apparatus  10  mounted on the front side of the steering base  2 , the side adjacent to the occupant. The airbag apparatus  10  of this embodiment is mounted to the steering base  2  in such a manner as to move in a front-back direction (toward and away from an occupant) so that when a module cover  20  of the airbag apparatus  10  is pushed so as to move the airbag apparatus  10  towards the steering base  2 , a horn switch is activated to blow a horn. 
   In one embodiment, a base plate  6  comprising a horn switch is disposed in front of the steering base  2  and the airbag apparatus  10  is joined to the base plate  6  with a guide shaft  41 . Between the base plate  6  and the airbag apparatus  10 , a coil spring  40  may be disposed that biases the airbag apparatus  10  away from the base plate  6 . The airbag apparatus  10 , the steering wheel  1 , and the horn switch are described below. 
   Referring to  FIG. 2 , the airbag apparatus  10  includes a retainer  11 , a folded airbag  13  mounted to the retainer  11  by operation of an airbag mounting ring  12 , an inflator  14  operable to inflate the airbag  13 , and a synthetic-resin module cover  20  covering the folded airbag  13 . The module cover  20  is constructed to be torn open when the airbag  13  inflates. 
   Referring now to  FIG. 3 , the retainer  11  has a main plate  11   a  disposed in front of the steering base  2 . The main plate  11   a  has an inflator opening  11   b  through which the inflator  14  is inserted. Around the opening  11   b , insertion holes (the reference numerals are omitted) are provided to receive stud bolts  12   a  that project outward from the airbag mounting ring  12 . 
   The proximal end of the airbag  13  comprises an inflator insertion hole (the reference numeral is omitted). The airbag  13  and the inflator  14  are frontally mounted to the retainer  11  by placing a periphery of the inflator insertion hole onto a periphery of the inflator opening  11   b  of the main plate  11   a . The airbag  13  and the inflator  14  are then retained by operation of the airbag mounting ring  12 . Stud bolts  12   a  of the airbag mounting ring  12  are inserted into bolt insertion holes (not shown) disposed around the inflator insertion hole and the bolt insertion holes of the main plate  11   a.    
   The distal end of the inflator  14  is inserted from the back into the inflator opening  11   b , and a flange  14   a , disposed around the side periphery of the inflator  14 , is placed on the periphery of the inflator opening  11   b . The stud bolts  12   a  are also inserted into bolt insertion holes (the reference numeral is omitted) of the flange  14   a . Nuts (not shown) are tightened to the stud bolts  12   a , thereby securing the airbag  13 , the airbag mounting ring  12 , and the inflator  14  to the main plate  11   a.    
   Still referring to  FIG. 3 , module cover mounting pieces  11   c  and  11   d  project from the outer rim of the main plate  11   a  (in this embodiment, the upper rim and the lower right and left rims) and are operable to secure the module cover  20  to the retainer  11 . The mounting piece  11   c  disposed at the upper rim of the main plate  11   a  projects towards the back of the main plate  11   a , while the mounting pieces  11   d  and  11   d  disposed on the lower right and left rims project towards the front of the main plate  11   a.    
   Referring back to  FIG. 2 , the module cover  20  has a main surface  21  covering the front of the retainer  11  and a leg-like piece  22  projecting from the back of the main surface  21 . The leg-like piece  22  is secured to the mounting pieces  11   c  and  11   d  with fasteners  11   e  or the like. The outer periphery  25  of the main surface  21  extends to the side of the airbag apparatus  10  relative to the leg-like piece  22 , and covers the proximal ends of the spokes  3 L,  3 R, and  3 D ( FIG. 1 ). 
   Still referring to  FIG. 2 , the outer surface of the lower spoke  3 D adjacent to the occupant forms, at the center of the steering wheel  1 , a receding slope withdrawing from the occupant. The part adjacent to a steering column (not shown) relative to the receding slope forms a radial surface substantially perpendicular to the axis of the steering column. The lower rim  24  of the main surface  21  faces the radial surface with a specified space therebetween. The portion of the radial surface adjacent to the receding slope has a projecting strip  9  that constructs a half of the concealer. 
   As shown in  FIGS. 1-3 , the projecting strip  9  is substantially arcuate and extends, with almost the same radius, along the steering column. 
   Referring now to  FIG. 2 , the lower rim (outer rim)  24  of the module cover  20  which covers the spoke  3 D is located outside the projecting strip  9 , or in the vicinity of the outer periphery of the projecting strip  9 . The lower rim  24  constructs the other half of a concealer. The lower end of the lower rim  24  (the end parallel to the axis of the steering column, the right end in  FIG. 2 ) is located lower than the upper rim of the projecting strip  9  (on the right in  FIG. 2 ). 
   Referring to  FIG. 3 , one aspect of the steering wheel  1  and the airbag apparatus  10  includes the interior of the airbag apparatus  10  being covered with the concealer constructed of the projecting strip  9  and projecting from the occupant-side surface of the lower spoke  3 D and the lower rim  24  of the module cover  20 . This structure prevents the interior of the airbag apparatus  10  from being viewed even if the steering wheel  1  were to be turned such that the spoke  3 D approaches the so called three or nine o&#39;clock position. 
   The concealer structure eliminates the need for mounting a separate blind cover to the module cover  20 , thereby facilitating manufacture and providing an aesthetic appearance. 
   The structures of the retainer  11  of the airbag apparatus  10 , the base plate  6 , and the horn switch and are described below. 
     FIG. 3  illustrates one embodiment including a horn-switch-contact retaining piece  16  that projects outward from each of the right and left opposite rims and the lower rim of the main plate  11   a  of the retainer  11 . The contact retaining pieces  16  project from the main plate  11   a  toward the occupant. From the ends of retaining pieces, extensions  16   a  extend towards the side of the airbag apparatus  10  in a direction substantially orthogonal to the front/back direction of the airbag apparatus  10 . 
   One contact  30  of the horn switch (not shown) is disposed on the back of each extension  16   a . Each extension  16   a  has an opening  16   b  for the guide shaft  41  to pass through and guide the front/back movement of the airbag apparatus  10 . 
   A base plate  6  is disposed on the back of the main plate  11   a . As shown in  FIG. 3 , the base plate  6  of this embodiment has a substantially “U” shape in plan view, and is disposed along the right and left sides and the lower side of the main plate  11   a . Airbag apparatus support pieces  7  project outward from the both ends and the middle (the lateral center of the portion along the lower side of the main plate  11   a ) of the base plate  6  in the position where they overlap the contact retaining pieces  16  of the main plate  11   a.    
   At the end of each support piece  7 , an opposing portion  7   a  is provided which faces the back of the extension  16   a  of each contact retaining piece  16 . The opposing portion  7   a  has a contact  31  opposed to the contact  30  of the extension  16   a . To the opposing portion  7   a , a guide-shaft mounting nut (the reference numeral is omitted) is fixed. 
   As shown in  FIG. 2 , the guide shaft  41  is fixed to the opposing portion  7   a  such that the proximal end of guide shaft  41  is screwed into the nut of the opposing portion  7   a  and projects from the opposing portion  7   a  toward the occupant. The guide shaft  41  passes through the front opening  16   b  of the extension  16   a  via an insulating spacer (the reference numeral is omitted). A flange (the reference numeral is omitted) is provided at the end of the guide shaft  41  and operates as a stopper. 
   Still referring to  FIG. 2 , a coil spring  40  is disposed around the guide shaft  41 , compressed between the extension  16   a  and the opposing portion  7   a.    
   In mounting the airbag apparatus  10  to the steering base  2 , the base plate  6  (joined in advance to the retainer  11 ) is superposed on the front surface of the steering base  2 , and a leg-like piece  6   a  is fixed to the steering base  2  with bolts or rivets (not shown). 
   In this embodiment, when the base plate  6  is joined to the steering base  2 , the opposing portions  7   a  overlap with the bases of the spokes  3 L,  3 R, and  3 D. As shown in  FIG. 2 , mounts  8  for supporting the opposing portions  7   a  are provided at the bases of the spokes  3 L,  3 R, and  3 D. The opposing portions  7   a  come into engagement with the mounts  8 . 
   The horn blowing operation of the steering wheel  1  with the airbag apparatus  10  is described below in conjunction with the embodiments of  FIGS. 2 and 3 . 
   When the module cover  20  is depressed, the module cover  20  and retainer  11  (the entire airbag apparatus  10 ) retract together. Because the base plate  6  is integrated with the steering wheel  1 , the base plate  6  is not retracted even when the module cover  20  is depressed. Thus the contacts  30  and  31 , retained by the retainer  11  and the base plate  6 , respectively, come into close contact with each other thereby energizing and blowing the horn (not shown). 
   On release of the module cover  20 , the retainer  11  is pushed back toward the occupant by the action of the coil spring  40  returning to its normal position shown in  FIG. 2 . Thus, the contacts  30  and  31  are separated, de-energizing and stopping the horn from blowing. 
   It is to be understood that the above-described embodiments are merely an example of the invention, and the invention is not limited to the embodiments described above. 
   For example, the embodiment has a structure in which when the module cover is depressed, the entire airbag apparatus is retracted to blow the horn. However, the invention may also be applied to a steering wheel and airbag in which only the module cover is retracted to blow the horn when the module cover is depressed. 
   Furthermore, although one embodiment disclosed includes a three-spoke type, the number of spokes is not limited to three. The concealer, comprising a projecting strip and an outer rim of a module cover, may be configured to operate with any spoke configuration. 
   The disclosure of Japanese Patent Application No. 2005-228355 filed on Aug. 5, 2005 is incorporated herein as a reference. 
   While the invention has been explained with reference to the specific embodiment of the invention, the explanation is illustrative, and the invention is limited only by the appended claims.