Abstract:
A vehicle includes a receiver forming an aperture therein and having first and second gear racks at opposing sides of the aperture. A steering column armature assembly is received within the receiver aperture and includes first and second gears engaged with the first and second gear racks, respectively, in a manner to facilitate counter-rotation of the first and second gears as the steering column armature assembly is moved along the first and second gear racks. The first and second gears are selectively lockable together to prevent movement of the steering column armature assembly along the first and second gear racks. The first and second gears include an energy absorber positioned therebetween for dissipating energy when the first and second gears are forcibly displaced and counter-rotate with respect to each other in a high energy impact.

Description:
TECHNICAL FIELD 
     The present invention relates to a vehicle steering column assembly including a rotating, traveling energy absorber for energy dissipation in a high energy impact. 
     BACKGROUND OF THE INVENTION 
     Vehicle steering column assemblies often include energy dissipation features for dissipating energy when an axial force is applied to the steering column. Such energy dissipation assemblies typically include multiple components attached to the movable steering column and to the cross-car beam or instrument panel support structure. The energy dissipation component generally includes one or more deformable metal components which are deformed automatically when the steering column is forcibly collapsed. 
     Such assemblies may be labor-intensive and expensive to assemble as a result of the multiple components involved and the fact that the energy dissipation components associated with the steering column and the instrument panel support structure must be attached after installation of the steering column assembly into the vehicle. This adds difficulty and expense to the steering column assembly operation. 
     Accordingly, it is desirable to provide a simplified steering column assembly including an energy dissipation structure which does not require additional installation steps for assembly. 
     DISCLOSURE OF THE INVENTION 
     The present invention overcomes the above-referenced shortcomings of the prior art steering column assemblies by providing a steering column armature assembly including an integral rotating, traveling energy absorber which is installed with the steering column assembly into the vehicle, and does not require additional installation steps. 
     More specifically, the present invention provides a vehicle including a receiver forming an aperture therein and having first and second gear racks at opposing sides of the aperture. A steering column armature assembly is received within the receiver aperture and includes first and second gears engaged with the first and second gear racks, respectively, in a manner to facilitate counter-rotation of the first and second gears as the steering column armature assembly is moved along the first and second gear racks. The first and second gears are selectively lockable together to prevent movement of the steering column armature assembly along the first and second gear racks. The first and second gears include an energy absorber positioned therebetween for dissipating energy when the first and second gears are forcibly displaced and counter-rotate with respect to each other in a high energy impact. 
     Preferably, a clutch is positioned between the first and second gears, and the energy absorber comprises a pin extending from one of the gears and cooperating with a slot formed in the clutch. The slot has a width less than the width of the pin, whereby forced counter-rotation of the first and second gears causes the pin to be dragged through the slot which forcibly widens the slot, thus dissipating impact energy. The first and second gears are axially movable toward each other for locking and away from each other for unlocking. At least one of the first and second gears includes side teeth facing corresponding side teeth on the clutch for locking. 
     Accordingly, an object of the invention is to provide an improved vehicle steering column assembly including an energy absorber mechanism which is installed integrally with the steering column assembly and does not require additional manufacturing steps. 
    
    
     Other objects, features and advantages of the present invention are readily apparent from the following detailed description of the best mode for carrying out the invention when taken in connection with the accompanying drawings. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 shows a schematic perspective view of a cross-car beam and steering column assembly in accordance with the present invention; 
     FIG. 2 shows an exploded perspective view of a cross-car beam and steering column assembly in accordance with the present invention; 
     FIG. 3 shows a perspective view of a partially disassembled steering column armature assembly in accordance with the present invention; 
     FIG. 4 shows an end perspective view of the assembly of FIG. 3; 
     FIG. 5 shows a top perspective view of the assembly of FIG. 3; 
     FIG. 6 shows a side view of the assembly of FIG. 3; 
     FIG. 7 shows a plan view of a steering column armature assembly in accordance with the present invention; 
     FIG. 8 shows a perspective view of the assembly of FIG. 7; 
     FIG. 9 shows a side view of the assembly of the FIG. 7; 
     FIG. 10 shows an end view of the assembly of FIG. 7; 
     FIG. 11 shows an exploded perspective view of an instrument panel-assembly and cross-car beam in accordance with the present invention; 
     FIG. 12 shows a perspective view of a cross-car beam in accordance with the present invention; 
     FIG. 13 shows an enlarged partial perspective view of the cross-car beam shown in FIG. 12; 
     FIG. 14 shows an exploded view of the assembly as shown in FIG. 7; 
     FIG. 15 shows a partial perspective view of the steering column armature assembly shown in FIG. 7 received within the cross-car beam structure shown in FIG. 13; 
     FIG. 16 shows a cut-away perspective view of the assembly of FIG. 15 with the telescope assembly in the unlocked position; 
     FIG. 17 shows a cut-away perspective view of the assembly of FIG. 15 with the telescope assembly in the locked position; 
     FIG. 18 shows a vertical cross-sectional view of the assembly of FIG. 16; 
     FIG. 19 shows a vertical cross-sectional view of the assembly of FIG. 17; 
     FIG. 20 shows a perspective view of a clutch in accordance with the present invention; 
     FIG. 21 shows a perspective view of a second gear engageable with the clutch of FIG. 20; 
     FIG. 22 shows a perspective view of a hub driver in accordance with the present invention; 
     FIG. 23 shows a perspective view of a driven hub engageable with the hub driver of FIG. 22; 
     FIG. 24 shows a perspective view of a tilt locking feature in accordance with the present invention; 
     FIG. 25 shows a perspective view of a steering column armature in accordance with the present invention; 
     FIG. 25 a  shows a reverse partial perspective view of the armature of FIG. 25; 
     FIG. 26 shows a plan view of a clutch in accordance with the present invention; and 
     FIG. 27 shows a comparative schematic illustration of packaging space required by a prior art steering column assembly in comparison with the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 shows a schematic perspective view of a vehicle  10  in accordance with the present invention. The vehicle  10  includes A-pillars  12 , 14 , with a cross-car beam  16  connecting the A-pillars  12 , 14 . A steering column armature assembly  18  is integrated with the cross-car beam  16  for mounting a steering wheel  20  in the vehicle. 
     In the preferred embodiment of the invention shown in FIG. 2, a partially disassembled steering column armature assembly  18  is shown prior to installation within an aperture  22  formed in the cross-car beam  16 . Preferably, the cross-car beam  24  is a cast component, wherein the aperture  22  is cast integrally therein, and the gear racks  26 , 28  are formed on upper and lower sides of the aperture  22 . The gear racks  26 , 28  at the upper and lower edges of the aperture  22  are configured to engage the gear sets  30 , 32  of the steering column armature assembly  18  such that the steering column armature assembly  18  may be telescopically adjusted with respect to the aperture  22  by moving the gear sets  30 , 32  along the gear racks  26 , 28 . In this configuration, a single gear of the gear sets  30 , 32  may act as a single attachment component for directly connecting the pivot joint  34  of the partially disassembled steering column armature assembly  18  to the cross-car beam  16 . 
     FIGS. 3-6 show various views of the partially disassembled steering column armature assembly  18 , which includes the gear sets  30 , 32  and armature  36  which houses the steering column  38 . 
     FIGS. 7-10 show the fully assembled steering column armature assembly  18 . As shown, the steering column armature assembly  18  includes a housing  40  having rollers  42 , 44 , 46  for rolling movement within the aperture  22  of the cross-car beam  16 , as shown in FIG.  15 . The steering column armature assembly  18  shown in FIGS. 7-10 is a self-contained assembly, including tilting, telescoping and energy absorption features incorporated therein. The steering column armature  36  is pivotable about the pivot joint  34  when unrestricted by the tilt locking feature  50 , to be described below. Also, the entire steering column armature assembly is movable along the aperture  22  for telescoping adjustment when unrestricted by the telescope locking feature  52 , which is incorporated within the gear sets  30 , 32 , to be described below. 
     A single bail handle  54  is operatively connected to the tilt locking feature  50  and to the telescope locking feature  52  for selectively disengaging the tilt locking feature and telescope locking feature for adjustment of the steering column  38 . 
     FIG. 11 shows an exploded view of various instrument panel and column components, including the upper instrument panel substrate  56  and lower instrument panel substrate  58 , which cooperate to enclose the cross-car beam  16 . Also, a grommet  60  and shroud assembly  62  are provided for enclosing the steering column assembly. 
     FIGS. 12 and 13 show additional perspective views of the cross-car beam  16 . In FIG. 13, the upper and lower gear racks  26 , 28  of the aperture  22  are clearly visible. 
     The functionality of the steering column armature assembly  18  is most clearly understood with reference to the exploded view of FIG.  14 . The single handle  54  is connected to the actuator locks  64 , 66 , which cooperate with the bulkhead stabilizer teeth  68  to form the tilt locking feature  50 . As shown in FIG. 24, the actuator lock  64  has an aperture  120  for receiving the single handle  54 , and a locking end  122  which cooperates with the lock teeth  124  and stabilizer teeth  68  of the armature assembly  36 , shown in FIG. 25, to form the tilt locking feature  50 . The hub drivers  70 , 72  are connected to the respective first gears (outer gears)  74 , 76 , respectively, and to the actuator locks  64 , 66 . A clutch  78 , 80  is secured to each first gear  74 , 76 . As shown in FIG. 26, each clutch  78 , 80  includes two enlarged holes  82 , 84  with corresponding energy dissipating slots  86 , 88 . Pins extending from the respective first gear  74 , 76  engage within the holes  82 , 84 , and are forced through the energy dissipating slots  86 , 88  in a crash situation for energy dissipation when the clutch  78 , 80  is forced to rotate with respect to the respective first gear  74 , 76 . The pins  90 , 92  engageable within the holes  82 , 84  are shown in FIG.  14 . 
     The second gears (inner gears)  94 , 96  are attached to the driven hubs  98 , 100 , and assembled to the armature  102 . A hub driver  70  and driven hub  98  are shown in FIGS. 22 and 23. Severely canted mating threads  118 , 120  are provided to enable the fast lead operation. Preferably, the hub driver  70  and driven hub  98  are molded components. 
     When the single handle  54  is rotated approximately 20 degrees, the actuator locks  64 , 66  and fast lead hub drivers  70 , 72  also rotate 20 degrees. With this rotation, the driven hubs  98 , 100  move approximately 0.125 inch, taking the inner gears  94 , 96  with them. This unlocks the actuator locks  64 , 66  from the bulkhead stabilizer teeth  68 . At this point, only column tilt can be adjusted. 
     When the single handle  54  is rotated approximately 20 degrees more for a total of 40 degrees, the actuator locks  64 , 66  and fast lead screw hub drivers  70 , 72  also rotate 20 degrees more. With this rotation, the driven hubs  98 , 100  move approximately 0.125 inch more, taking the inner gears  94 , 96  with them. The tilt feature is re-locked at this point and, as shown in FIG. 18, the side teeth  104  of the inner gear  94  are now spaced away from the side teeth  106  of the clutch  78 , thereby allowing free counter-rotation of the inner gear  94  with respect to the attached clutch  78  and outer gear  74 . This counter-rotation is facilitated by the inner gear  94  being engaged only with the rack  28  at the bottom  108  of the aperture  22 , and the outer gear  74  being engaged only at the rack  28  at the top  110  of the aperture  22 . The opposite edge of each of the gears  74 , 94  is provided with clearance from the opposing aperture wall. Accordingly, with the gear teeth of the inner gear  94  only engaged at the bottom, and the gear teeth of the outer gear  74  only engaged at the top, telescoping movement of the steering column assembly occurs by means of counter-rotation of the gears  74 , 94 . At this point of 40 degrees of handle  54  movement, only column telescope can be adjusted. 
     Moving the single handle  54  back 40 degrees reverses the hub drivers  70 , 72  and re-engages the side teeth  104 , 106  of the inner gear  94  and clutch  78 , thereby locking in the newly-selected tilt and telescope positions. This locked position is shown in FIGS. 17 and 19, with FIGS. 16 and 18 illustrating the unlocked position. As shown in FIG. 19, the face teeth  104 , 106  of the inner gear  94  and clutch  78  are engaged, thereby preventing counter-rotation of the inner gear  94  and outer gear  74 , preventing telescoping movement. 
     Returning to FIG. 13, the cross-car beam aperture  22  (receiver box) includes the gear racks  26 , 28 . As shown, each gear rack  26 , 28  includes an outer row  114  and inner row  112  of teeth. The outermost teeth  114  engage the outer gear  74  at the bottom of the aperture  22 , and the innermost teeth  112  engage the inner gear  94  at the top of the aperture  22 . This gear arrangement stabilizes the column assembly. 
     During the crash event, the side teeth  104 , 106  of the inner gear  94  and clutch  78  prevent relative rotation between the clutch  78  and inner gear  94 . The engaging side teeth  104 , 106  of inner gear  94  and the clutch  78  are shown in FIGS. 20 and 21. However, the clutch  78  is pinned to the outer gear  74  by the pins  90 , 92  shown in FIG.  14 . Turning to FIG. 26, the pins  90 , 92  engage within the holes  80 , 82  of the clutch  78 . The holes  82 , 84  are larger than the corresponding slots  86 , 88 , therefore the pins  90 , 92  stay in position under normal conditions. However, in a crash situation, the weak point is the energy dissipation slots  86 , 88  on the clutch  78 . When sufficient axial force is exerted on the steering column, the outer gear  74  forcibly counter-rotates with respect to the inner gear  94 , and the pins  90 , 92  deform the slots  86 , 88  of the clutch  78  and dissipate the energy. In an alternative embodiment, the pins  90 , 92  and slots  86 , 88  may be replaced with a pair of wires which are cold-formed by dragging the wires through bent slots during the crash event. 
     FIG. 27 is a schematic illustration of the packaging space required by a sample prior art steering column assembly A in comparison with the packaging space required by the present steering column assembly B. As shown, the invention provides significant packaging space savings by incorporating tilt, telescope and energy dissipation features in the removable steering column armature assembly. 
     While the best mode for carrying out the invention has been described in detail, those familiar with the art to which this invention relates will recognize various alternative designs and embodiments for practicing the invention within the scope of the appended claims.