Abstract:
A rotating cable device preferably for use in a steering column assembly couples a drive member to a driven member of the assembly for rotation and without any lost motion or release of unwanted absorbed energy, which could potentially create inefficiencies in operation and undesirable noise. A rigid sheath of the device extends along a non-linear centerline and a resilient tube preferably extends through the sheath. A flexible cable of the device extends through the tube and couples between the members for rotation. The cable device enables versatility in the arrangement and orientation of the drive and driven members in a variety of different steering column and transmission shift mount applications for vehicles.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a steering column assembly, and more specifically to a steering column assembly having a rotating drive cable device. 
       BACKGROUND OF THE INVENTION 
       [0002]    Known drive cable devices typically consist of a flexible sheath and a drive cable. The sheath is designed to support the drive cable with both the sheath and the cable being flexible to allow routing in non-linear geometries. The flexibility of the sheath, or bending stiffness, depends on the amount of cable flexure required to allow routing in the non-linear geometry and the ability to resist normal forces of the cable as torques is applied. This type of drive cable device configuration induces high forces into the drive and driven members and allows significant energy to be stored in the drive cable device. Unfortunately, when the applied torque to the cable is reversed, the stored energy in the cable is released and thus induces a “clunk” into the system. Because such cable devices store energy, they create unwanted noise into the applied assembly. 
         [0003]    Typically, the rotating rotor of the electric motor attaches directly to the mechanism it generally automates or drives. Such rigid connections limit placement of the motor in the column assembly and may require complicated and expensive couplings such as worm gears. In general terms, the versatility in the packaging of a steering column is limited and often requires numerous and a variety of parts that contribute toward expensive manufacturing costs. Unfortunately, a degree of motion is lost when a torque is applied to known rotating and sheathed cables making such cables less than ideal for the applications described above. 
       SUMMARY OF THE INVENTION 
       [0004]    A rotating cable device preferably for use in a steering column assembly couples a drive member to a driven member of the assembly for rotation and without any lost motion or release of unwanted absorbed energy, which could potentially create inefficiencies in operation and undesirable noise. A rigid sheath of the device extends along a non-linear centerline and a resilient tube preferably extends through the sheath. A flexible cable of the device extends through the tube and couples between the members for rotation. The cable device enables versatility in the arrangement and orientation of the drive and driven members in a variety of different steering column and transmission shift mount applications for vehicles. 
         [0005]    Preferably, the drive member is an electric motor and the rotor of the motor couples directly to the cable of the cable device. Use of the device increase versatility in the placement of the motor and reduces or eliminates the need for rigid connections and complicated and expensive couplings such as worm gears. In general terms, the versatility in the packaging of a steering column is enhanced and the variety of necessary parts is reduced. Operation of the steering column assembly is improved and unwanted noise during operation is reduced. 
         [0006]    Other objects, features and advantages of the present invention include a steering column assembly that is compact, robust, simple and inexpensive to manufacture, and requires little or no maintenance and in service has a long and useful life. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    Other advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein: 
           [0008]      FIG. 1  is an exploded perspective view of a rotating drive cable device embodying the present invention; 
           [0009]      FIG. 2  is a cross section of the rotating drive cable device; 
           [0010]      FIG. 3  is a perspective view of an end portion of a cable of the drive cable device; 
           [0011]      FIG. 4  is a perspective view of a steering column assembly having the drive cable device; 
           [0012]      FIG. 5  is a perspective view of a second embodiment of a steering column assembly having the drive cable device; and 
           [0013]      FIG. 6  is a perspective view of a third embodiment of a steering column assembly having the drive cable device. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0014]    Referring to  FIGS. 1-4 , a rotating cable device  20  embodying the present invention preferably couples a drive member  22  to a driven member  24  for rotational movement. The cable device  20  has a flexible cable  26 , a flexible tube  28  and a rigid sheath  30  all co-extending concentrically along a non-linear centerline  32 . Preferably, the cable  26  is longer than the tube  28  which is longer than the sheath  30 . Hence, opposite end portions  34 ,  36  of the cable  26  project axially beyond opposite end segments  38 ,  40  of the tube  28  which project axially beyond opposite end sections  42 ,  44  of the sheath  30 . 
         [0015]    The cable  26  is preferably made of steel having spun strands for providing strength and flexibility. A mid portion  46  of the cable  26  is axially aligned or centered to the tube  28  and has a longitudinal length that is slightly longer than a longitudinal length of the tube  28 . Because the cable  26  rotates with respect to the tube  28 , the mid portion  46  of the tube  28  is fitted loosely through the tube  28 . To enhance flexibility and reduce rotational friction between the tube  28  and the cable  26 , the mid portion  46  is substantially cylindrical and opposes a cylindrical inner surface  48  of the tube  28 . As best shown in  FIG. 3 , the end portions  34 ,  36  of the cable  26  are preferably non-cylindrical and have at least one flat or circumferentially keyed side  50  (e.g. a square cross sectional profile) for rotational engagement to the drive and driven members  22 ,  24 . This non-cylindrical or square profile may be machined pressed into the otherwise cylindrical cable during manufacturing. 
         [0016]    The tube  28  is preferably made of a resilient and flexible rubber-like material for in-part reducing system noise or clunking of the cable  26 . For ease of assembly, the tube  28  loosely fits through the sheath  30  so that a cylindrical outer surface  52  of the tube  28  opposes a cylindrical inner face  54  of the sheath  30 . Preferably, the outer surface  52  and the inner face  54  radially define an annular cavity  56  for press fitting of opposite end connectors  58 ,  60  of the device  20  therein. 
         [0017]    The end connectors  58 ,  60  are preferably made of injection molded plastic and function to snap fit the device  20  to the respective drive and driven members  22 ,  24  while generally stabilizing the cable  26  for smooth rotational operation. Each connector  58 ,  60  preferably has an annular base  62 , a tubular sleeve  64  projecting axially inward from the base  62 , a tubular collar  66  projecting axially outward from the base  62  and a snap fit fastener or cage  68  for engagement to the respective drive and driven members  22 ,  24 . 
         [0018]    During assembly of the device  20 , the end segments  38 ,  40  of the tube  28  are abutted axially against the annular bases  62  of the respective connectors  58 ,  60 . The resiliency of the tube  28  exerts a force, directed radially outward, against the sleeves  64  for a tight fit. Because the sleeves  64  are axially longer than the respective end segments  38 ,  40  of the tube  28 , a distal portion of the sleeves  64  is located in the cavity  56  and fitted snugly and radially between the inner face  54  of the sheath  30  at the end sections  42 ,  44  and the outer surface  52  of the tube  28 . One skilled in the art would now know that the end sections  42 ,  44  of the sheath  30  may be flared radially outward to assist in the fitted axial receipt of the sleeves  64 . Moreover, if the end sections  42 ,  44  are flared, the annular cavity  56  may only be present or defined at the end sections  42 ,  44 , and the remaining longitudinal length or mid portion of the sheath  30  may be in close contact generally with the mid portion of the tube  28 . 
         [0019]    With end segments  38 ,  40  of the tube  28  inserted fully into the sleeves  64 , a bushing  70  of each connector  58 ,  60  slides axially over the end portions  34 ,  36  of the cable  26  and until the bushings  70  abut the bases  62  of the respective connectors  58 ,  60 . When the bushings  70  are abutted or fully installed, they are axially aligned to and located radially inward from the collars  66  of the respective connectors  58 ,  60 . Preferably, the bushings  70  tightly fit to the mid portion  46  of the cable  26  for maintaining axial alignment of the cable  26  with respect to the tube  28  of the sheath  30 . As best shown in  FIG. 2 , the bushing  70  in connector  60  may be in a rotational contact with the collar  66 . Preferably, the collars  66  are made of a plastic or plastic-like material with friction reducing characteristics. 
         [0020]    Referring to  FIG. 4 , the rotating cable device  20 , drive member  22  and driven member  24  are preferably suited for (i.e. as part of) a steering column assembly  72 . The drive member  22  is preferably an electric motor having a rotating rotor  74  contoured to connect to the end portion  34  of the cable  26 . The fastener  68  preferably snap fits to the same stationary structure that supports the motor  22 . The driven member  24  may be an adjustment mechanism of the assembly  72  that functions to telescopically and/or tilt adjust a steering column  76  of the assembly  72 . This automated adjustment may be limited to locking the steering column  76  in-place once the desired position is established or may function to both position the column  76  and generally lock it in the desired position. One particular steering column application or adjustment mechanism  24  is taught in U.S. Pat. No. 7,055,860, and is incorporated herein by reference in its entirety. The novel application of the cable device  20  enables versatile and remote placement of the motor  22  in any variety of positions. 
         [0021]    Referring to  FIG. 5 , a second embodiment of a steering column assembly  172  is illustrated wherein like elements to the first embodiment have the same identifying numerals except with the summed addition of one hundred. In the second embodiment, the assembly  172  has a rotating cable device  120 , a drive member  122  and a driven member  124 . The drive member  122  is preferably an electric motor having a rotating rotor  174  contoured to connect to an end portion  134  of a rotating cable  126 . The driven member  124  is generally a transmission shifter mechanism that controls a transmission  80  of a vehicle. Such an application is taught in U.S. Pat. No. 7,137,499 and is incorporated herein by reference in its entirety. Other applications for the rotating cable device  120  may include a one-touch steering column, a power adjustable steering column, and electric transmission shifter and an electric steering column lock. 
         [0022]    Referring to  FIG. 6 , a third embodiment of a steering column assembly  272  is illustrated wherein like elements to the first embodiment have the same identifying numerals except with the summed addition of two hundred. The steering column assembly  272  is commonly referred to as a power adjustable steering column. In the third embodiment, the assembly  272  has a rotating cable device  220 , a drive member  222  and a driven member  224 . The drive member  222  is preferably an electric motor having a rotating rotor  274  contoured to connect to an end portion  234  of a rotating cable  226 . As discussed above, the driven member  224  may be an adjustment mechanism of the assembly  272  that functions to telescopically and/or tilt adjust a steering column  276  of the assembly  272 . 
         [0023]    While the forms of the invention herein disclosed constitute presently preferred embodiments, many others are possible. It is not intended herein to mention all the possible equivalent forms or ramifications of the invention. It is understood that terms used herein are merely descriptive, rather than limiting, and that various changes may be made without departing from the spirit or scope of the invention.