Patent Publication Number: US-11661099-B2

Title: Handwheel actuator modular interface

Description:
TECHNICAL FIELD 
     Example embodiments generally relate to vehicle control technology and, more particularly, relate to an interface between modules (or components) of a handwheel actuator in a steer by wire system. 
     BACKGROUND 
     Vehicles are consistently moving toward the integration of electrical or electro-mechanical components that perform various vehicle functions that were previously performed using mechanical linkages. Drive by wire, steer by wire and brake by wire are some examples of this migration away from mechanical linkages. A result of this migration is that vehicles may become lighter, and easier to service and maintain. 
     However, in spite of the advantages noted above, the design and integration of new components for these systems may sometimes be challenging for manufacturers. Accordingly, it may be desirable to define certain standard interfaces between components so that such components can be reliably integrated into different vehicle models and types regardless of who the individual manufacturers were for specific components. 
     BRIEF SUMMARY OF SOME EXAMPLES 
     In accordance with an example embodiment, a handwheel actuator for a steer by wire system may be provided. The handwheel actuator may include a feedback actuator and a column for operably coupling a handwheel to the handwheel actuator. The column may include a column shaft extending from a first end of the column to a second end of the column. The feedback actuator may be operably coupled to the second end of the column and provides tactile feedback to an operator responsive to movement of the handwheel. The feedback actuator may include a torsion bar coaxial with the column shaft. The column shaft may be supported relative to a housing of the column by a first column shaft bearing disposed proximate to the first end of the column and a second column shaft bearing disposed proximate to the second end of the column. The torsion bar may extend into the column shaft past the second column shaft bearing and is operably coupled to the column shaft via a removable fastener disposed at a portion of the torsion bar that extends past the second column shaft bearing. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S) 
       Having thus described the invention in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein: 
         FIG.  1    illustrates a block diagram of a steer by wire system of a vehicle in accordance with an example embodiment; 
         FIG.  2    illustrates a schematic view of a handwheel actuator in accordance with an example embodiment; 
         FIG.  3 A  is a cross section view taken along an axis of a column shaft of the handwheel actuator in accordance with an example embodiment; 
         FIG.  3 B  is a closer view (in cross section) of the area in which the interface between modules of the handwheel actuator is formed in accordance with an example embodiment; 
         FIG.  3 C  is a cross section view along a plane perpendicular to the axis of the column shaft in accordance with an example embodiment; 
         FIG.  4 A  is a cross section view taken along an axis of a column shaft of the handwheel actuator showing an alternative structure for the interface between the modules of the handwheel actuator in accordance with an example embodiment; 
         FIG.  4 B  is a closer view (in cross section) of the area in which the interface is formed in accordance with an example embodiment; 
         FIG.  5 A  is a cross section view taken along an axis of a column shaft of the handwheel actuator showing another alternative structure for the interface between the modules of the handwheel actuator in accordance with an example embodiment; 
         FIG.  5 B  is a perspective view of a retaining clip on a threaded fastener in accordance with an example embodiment; 
         FIG.  6 A  is a cross section view taken along an axis of a column shaft of the handwheel actuator showing another alternative structure for the interface between the modules of the handwheel actuator in accordance with an example embodiment; 
         FIG.  6 B  is a perspective view of a retaining clip used to retain a threaded fastener in accordance with an example embodiment; 
         FIG.  7 A  is a cross section view taken along an axis of a column shaft of the handwheel actuator showing still another alternative structure for the interface between the modules of the handwheel actuator in accordance with an example embodiment; 
         FIG.  7 B  is a perspective view of a multi-lobe engagement structure in accordance with an example embodiment; 
         FIG.  7 C  is another perspective view of the multi-lobe engagement structure in accordance with an example embodiment; 
         FIG.  8 A  is a cross section view taken along an axis of a column shaft of the handwheel actuator showing another alternative structure for the interface between the modules of the handwheel actuator in accordance with an example embodiment; 
         FIG.  8 B  is a perspective view of a retaining clip used to retain a threaded fastener in accordance with an example embodiment; 
         FIG.  9 A  is a cross section view taken along an axis of a column shaft of the handwheel actuator showing another alternative structure for the interface between the modules of the handwheel actuator in accordance with an example embodiment; 
         FIG.  9 B  is a closer view of the interface of  FIG.  9 A ; and 
         FIG.  9 C  is a perspective view of a retaining clip used to retain a threaded fastener in accordance with an example embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Some example embodiments now will be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all example embodiments are shown. Indeed, the examples described and pictured herein should not be construed as being limiting as to the scope, applicability or configuration of the present disclosure. Rather, these example embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like reference numerals refer to like elements throughout. Furthermore, as used herein, the term “or” is to be interpreted as a logical operator that results in true whenever one or more of its operands are true. As used herein, operable coupling should be understood to relate to direct or indirect connection that, in either case, enables functional interconnection of components that are operably coupled to each other. 
     As noted above, it may be desirable to define certain component interfaces to consistently meet certain standards or specifications to ensure compatibility regardless of manufacturer. One such interface may be associated with steer by wire systems, and may relate to the feedback actuator of such a system.  FIG.  1    illustrates a block diagram of some components of a steer by wire system  100  in accordance with an example embodiment. Of note, although the components of  FIG.  1    may be part of or operably coupled to the vehicle, it should be appreciated that such connection(s) may be either direct or indirect. Moreover, some of the components of the steer by wire system  100  may be connected to the vehicle via intermediate connections to other components either of the chassis or of other electronic and/or mechanical systems or components. 
     Referring now to  FIG.  1   , the steer by wire system  100  may include a handwheel  110 , which is located with a vehicle for manual manipulation by a driver or operator of the vehicle. The handwheel  110  is typically a traditional steering wheel, and therefore may be round and rotatable about an axis. However, other structures could be substituted for implementation as the handwheel  110  in alternative embodiments. The movements (typically rotations) of the handwheel  110  are communicated to a handwheel actuator  120  that is operably coupled to the handwheel  110 . The handwheel  110  and/or the handwheel actuator  120  may also be operably coupled to one or more steering sensors  130  that may be configured to determine steering angle and/or torque input at the handwheel  110 . In some cases, the steering sensor  130  (or sensors) may be part of the handwheel actuator  120 . However, the steering sensor  130  could alternatively be a separate component. 
     In an example embodiment, the handwheel actuator  120  and/or the steering sensor  130  may be operably coupled to a controller  140 . In some cases, the controller  140  may be part of an electronic control system of the vehicle. The controller  140  may therefore also be configured to perform other tasks related or not related to steer by wire control or performance management. However, the controller  140  could be a dedicated or standalone controller in some cases. Processing circuitry (e.g., a processor and memory) at the controller  140  may process the information received by, for example, running one or more control algorithms based on the information received. The control algorithms may include instructions that can be stored by the memory for retrieval and execution by the processor. In some cases, the memory may further store one or more tables (e.g., look up tables) and various calculations and/or applications may be executed using information in the tables and/or the information to generate outputs to a steering motor  150  based on the inputs received (e.g., from the handwheel actuator  120  and/or steering sensor  130 ). 
     In an example embodiment, the steering motor  150  (or steering actuator) may be an electrical motor that is operably coupled to a steering assembly  160  to drive the steering assembly  160  to turn wheels  170  (typically front wheels) of the vehicle. The steering assembly  160  may include one or more of a chain, belt, steering gear(s), rack and pinion, direct drive, or other structures that communicate steering torque to the wheels  170 . 
     In an example embodiment, the handwheel actuator  120  may include subcomponents that may be made by different manufacturers, suppliers or sourcing agents, which are often simply referred to as original equipment manufacturers (OEMs). In this regard, for example, the handwheel actuator  120  may include a column  180  and a feedback actuator  190 . The column  180  may include structural interfaces to the handwheel  110  to enable the rotational inputs at the handwheel  110  to be communicated to the controller  140  for generation of inputs to the steering motor  150 . The feedback actuator  190  may include an electric motor and other components that are designed to provide feedback that gives operators a tactile response similar to that of conventional mechanical or hydraulic steering systems. 
     As noted above, the use of the handwheel actuator  120  creates significant flexibility in terms of enabling designers to easily change steering ratios and torque resistances or otherwise modify steering functionality. In this regard, for example, relatively simple software commands may enable such alteration instead of any physical component replacement or manipulation. Additionally, by not mechanically linking the handwheel  110  to the wheels  170 , greater flexibility is unlocked in terms of other aspects of vehicle design, including stowable handwheels and/or steering columns for self-driving options coming in the future. 
     Although it may be possible for the entire handwheel actuator  120  to be manufactured by a single OEM, the nature of competition in the global automotive sector, and the fact that different areas of specialization may be required to manufacture the column  180  than those required for manufacture of the feedback actuator  190 , may dictate that different OEMs could be used for each part. Moreover, the fact that it may be desirable to have the column  180  and the feedback actuator  190  be separate serviceable and individually replaceable components so that failure or service life exhaustion of one does not necessitate replacement of the other tends to motivate the modularization of the column  180  and the feedback actuator  190  as separate modules or components with an interface (e.g., a column-actuator interface  195 ) therebetween. If the same OEM produced both the column  180  and the feedback actuator  190 , the OEM would own the interfaces (including the column-actuator interface  195 ) therebetween. The OEM could theoretically define the interface anyway they wanted. However, if different OEMs were involved, or the potential for different OEMs existed, then the column-actuator interface  195  may become a potentially limiting component, and the incentive becomes strong to standardize or limit variation of certain aspects of the column-actuator interface  195 . 
     In order to provide a robust connection between the feedback actuator  190  and the column  180 , while still allowing for the potential of separate sourcing and servicing of the components, example embodiments may provide structures for defining the column-actuator interface  195 . Notably, components that form the column-actuator interface  195  may be part of the feedback actuator  190  or the column  180 , and need not be separate components or modules themselves. Thus, for example, in some cases, the column-actuator interface  195  may be defined as components of the column  180  and/or the feedback actuator  190  that interface with each other to operably couple the column  180  to the feedback actuator  190 . However, some components of the column-actuator interface  195  may be considered to be part of a separate module from each or either of the column  180  and the feedback actuator  190 . 
       FIGS.  2 - 9    demonstrate some specific structures that may be used to implement various aspects of the steer by wire system  100  of  FIG.  1   .  FIG.  2    illustrates a schematic view of a handwheel actuator  200 , which may be an example of the handwheel actuator  120  of  FIG.  1   . In  FIG.  2   , a column portion (or column  210 ) and feedback actuator portion (or feedback actuator  220 ) may be understood to be separable modules or component that may be joined at an interface therebetween (which form an example of the column-actuator interface  195  of  FIG.  1   ). The column  210  is an example of the column  180 , and the feedback actuator  220  is an example of the feedback actuator  190  of  FIG.  1   . 
       FIG.  3   , which is defined by  FIGS.  3 A,  3 B and  3 C , shows various components and structures that may define an interface between the column  210  and the feedback actuator  220  and therefore form portions of the column-actuator interface  195  of  FIG.  1   .  FIG.  4   , which is defined by  FIGS.  4 A and  4 B , shows an alternative structure for interface between the column  210  and the feedback actuator  220 .  FIG.  5   , which is defined by  FIGS.  5 A and  5 B  illustrates another alternative structure for the interface between the column  210  and the feedback actuator  220 .  FIG.  6   , which is defined by  FIGS.  6 A and  6 B , shows yet another alternative structure for interface between the column  210  and the feedback actuator  220 .  FIG.  7   , which is defined by  FIGS.  7 A,  7 B and  7 C , shows still another alternative structure for interface between the column  210  and the feedback actuator  220 .  FIG.  8   , which is defined by  FIGS.  8 A and  8 B , shows an alternative structure for interface between the column  210  and the feedback actuator  220 .  FIG.  9   , which is defined by  FIGS.  9 A,  9 B and  9 C , shows another alternative structure for interface between the column  210  and the feedback actuator  220 . 
     Referring to  FIGS.  2  and  3   , the column  210  may include an upper steering shaft  212  that may be supported or held in place by an upper steering jacket  214 . The upper steering jacket  214  may be operably coupled to a lower column casting  216 . The upper steering jacket  214  and the lower column casting  216  may combine to form a housing of the column  210 . The upper steering shaft  212  may be operably coupled to a handwheel (e.g., handwheel  110 ) at one end (i.e., a proximal end), and may be operably coupled to (or integrally formed with) a lower steering shaft  218  at the opposing end (i.e., a distal end thereof relative to the handwheel  110 ). The upper steering shaft  212  and the lower steering shaft  218  may combine to form a steering shaft or column shaft of the column  210 . 
     In an example embodiment, the upper steering jacket  214  may be operably coupled to the lower column casting  216  to enclose the lower steering shaft  218  entirely therein. In some cases, the lower column casting  216  and the upper steering shaft  212  may be operably coupled in such a way that permits (e.g., responsive to impact) the upper steering jacket  214  to slide deeper into the lower column casting  216  (e.g., telescopically retracting) to absorb impact. As such, a degree to which the upper steering jacket  214  can move within the lower column casting  216  may define how much movement of the handwheel  110  may be possible in an impact scenario. 
     The lower column casting  216  may include, in some cases, an access port  230  formed therein. The access port  230  may be an aperture or opening in a lateral side of the lower column casting  216  at a portion of the lower column casting  216  that is proximate to (although in some cases spaced apart slightly from) the feedback actuator  220 . The access port  230  may allow visibility and physical access into the lower column casting  216 , and more specifically grant access to a front end of the lower steering shaft  218 , which may be a distal end of the lower steering shaft  218  relative to the upper steering shaft  212 . A cover  232  may be provided to fit within or close the access port  230  to prevent access to the inside of the lower column casting  216 . Removal of the cover  232  may therefore provide the access described above. 
     The feedback actuator  220  may include a motor that is operably coupled to a driven shaft (e.g., stub shaft  226 ) that is generally coaxial with the column shaft. The operable coupling between the motor and the stub shaft  226  may be accomplished in many ways depending on the orientation and nature of the motor. For example, the motor could have a motor shaft that extends in the forward direction (i.e., relative to the front of the vehicle), which may be parallel to and offset from an axis of the upper steering shaft  212  and the lower steering shaft  218 . However, the motor shaft could alternatively be perpendicular to the column shaft or inline therewith in other alternative arrangements. As such, it may be appreciated that the motor shaft could be directly or indirectly coupled to the stub shaft  226  (e.g., via a belt, gear, etc.) in a number of different ways. The stub shaft  226  may be coaxial with a torsion bar  228  that is operably coupled to the stub shaft  226  to rotate with the stub shaft  226 . The motor and the stub shaft  226  may provide the feedback described above, which is fed through the lower steering shaft  218  and the upper steering shaft  212  to the driver via the handwheel  110 . 
     The stub shaft  226  and the torsion bar  228  may all be located in or housed within a feedback actuator casting  229 . In some cases, the motor and any components providing direct or indirect coupling between the motor and the stub shaft  226  may also be housed in the feedback actuator casting  229 . However, a proximal end of the torsion bar  228  (relative to the column shaft) and a proximal end of the stub shaft  226  (also relative to the column shaft) may each protrude slightly out of an opening formed in the feedback actuator casting  229 . The opening formed in the feedback actuator casting  229  may be adjacent to an opening at the forward end of the lower column casting  216  (e.g., where the column shaft terminates). 
     In this example, the upper and lower steering shafts  212  and  218  may act as a single column shaft although they are physically separate, but joined components. The column shaft may be supported proximate to each opposing end thereof by a respective bearing assembly. Thus, rotation of the column shaft within the column  210  may be fully supported at both ends. In an example embodiment, a first column shaft bearing  240  (or rear bearing) may be disposed at an end of the upper jacket  214  (e.g., a distal end of the upper jacket  214  relative to the lower column casting  216 ). A second column shaft bearing  242  (or middle bearing) may be disposed at or proximate to an end of the lower steering shaft  218 , which may also be proximate to an end of the lower column casting  216  (e.g., a proximal end relative to the feedback actuator  220 ). 
     Meanwhile, the feedback actuator  220  may only include a bearing to support the stub shaft  226 . In this regard, a feedback actuator bearing  244  (or forward bearing) may be provided proximate to a distal end of the stub shaft  226  (relative to the column shaft). The other end of the stub shaft  226  (i.e., the proximal end relative to the column shaft) may be supported after coupling of the torsion bar  228  to the lower steering shaft  218  (e.g., by the middle bearing). Accordingly, the rear bearing, middle bearing and the forward bearing(s) may combine to support the column shaft and the stub shaft  226 , when the column shaft and the stub shaft  226  are joined together as described herein. 
     In an example embodiment, the torsion bar  228  may be press fit into the stub shaft  226 . The stub shaft  226  may be press fit into the feedback actuator bearing  244 , and the feedback actuator bearing  244  may be press fit into the feedback actuator casting  229 . The second column shaft bearing  242  may also be press fit into the lower column casting  216 . However, the torsion bar  228  may be operably coupled to the lower steering shaft  218  via a removable fastener. Moreover, the removable fastener may be accessible and capable of being fastened or unfastened via the access port  230 . Accordingly, example embodiments may provide the removable fastener as the means by which to couple the column shaft to the stub shaft  226  of the feedback actuator  220  at a location proximate to the access port  230  and between the first and second column shaft bearings  240  and  242  (or rear and middle bearings). 
     In the example of  FIG.  3   , the torsion bar  228  extends out of the feedback actuator casting  229  and into the lower steering shaft  218  to a location or depth in the lower steering shaft  218  that is rearward of the second column shaft bearing  242 . However, although the stub shaft  226  also extends out of the feedback actuator casting  229  and into the lower steering shaft  218 , the stub shaft  226  does not penetrate as far as the second column shaft bearing  242 .  FIG.  3 A  is a cross section view of the handwheel actuator  200 , and  FIG.  3 B  is a cross section view of the interface between the feedback actuator casting  229  and the lower column casting  216  taken along an axis of the stub shaft  226 , the torsion bar  228 , and the column shaft (which are all coaxial after assembly). 
       FIG.  3 C  is a cross section view taken along a plane perpendicular to the axis of the torsion bar  228  at a location immediately rearward of the proximal end of the stub shaft  226  (looking forward). As shown in  FIG.  3 C , the proximal end of the stub shaft  226  (relative to the column  210 ) may include a torque limiting interface  245  formed with the column shaft to prevent over-application of torque to the torsion bar. The torque limiting interface  245  may be formed by projections  247  having a selected shape that project from the proximal end of the stub shaft  226  (relative to the column shaft). The projections  247  may fit within correspondingly shaped walls  249  formed at the proximal end of the lower steering shaft  218 . The walls  249  may leave a certain amount of clearance between themselves and the projections  247  under normal circumstances. If large enough amounts of torque are applied to cause contact between the projections  247  and the walls  249 , then torque transfer may occur between the projections  247  and the walls  249  thereby relieving the torsion bar  228 . 
     In the example embodiment of  FIG.  3   , proximal end of the torsion bar  228  may have a threaded receiver  250  formed therein, as best shown in  FIG.  3 B . The threaded receiver  250  may be aligned with receiving holes  252  formed in the lower steering shaft  218 , and a threaded fastener  254  (as one example of the removable fastener discussed above) may be passed into the receiving holes  252  and through the threaded receiver  250 . As can be appreciated from the descriptions above, the stub shaft  226  may be inserted into the lower steering shaft  218  to cause the stub shaft  226  and lower steering shaft  218  to rotate together, and then the lower steering shaft  218  may be rotated until the receiving holes  252  are visible and accessible through the access port  230  (i.e., with the cover  232  removed). The threaded fastener  254  may then be threaded into the threaded receiver  250  and torqued to specification to affix the lower steering shaft  218  to the torsion bar  228 . The fixing of the lower steering shaft  218  to the torsion bar  228  is desirably tight or rigid to avoid any (or as much as possible) clearance, freedom or play between the lower steering shaft  218  and the torsion bar  228 . 
     The example of  FIG.  3    is one way the feedback actuator  220  and the column  210  can be attached to each other via a standard interface that is both repeatable in new construction with different models of column  210  (or feedback actuator  220 ) and also repeatable to permit separation for servicing or replacement of just one of either the feedback actuator  220  or the column  210 . The threaded fastener  254  is therefore an example of a torque prevailing fastener (or removable fastener) that releasably secures the separate shaft portions of the feedback actuator  220  and the column  210  (i.e., the lower steering shaft  218  and the stub shaft  226 ) together. However, the removable fastener could be modified, altered or replaced in other embodiments. Moreover, other structural modifications may also be made to the interface in other areas, as will be discussed in greater detail below in associated with respective different embodiments. 
     In this regard,  FIG.  4 A  shows a cross section view similar to that of  FIG.  3 A  and  FIG.  4 B  shows a cross section view similar to that of  FIG.  3 B  with a different retention mechanism for the middle bearing (e.g., the second column shaft bearing  242 ). In this regard, whereas the second column shaft bearing  242  was press fit into the lower column casting  216  in the example of  FIG.  3   , the second column shaft bearing  242  is instead retained by a bearing retention plate  300  in the example of  FIG.  4   . The bearing retention plate  300  may be press fit into the opening formed in the end of the lower column casting  216 , and the second column shaft bearing  242  may be press fit into the bearing retention plate  300 . The example of  FIG.  4    is otherwise similar to the example of  FIG.  3   . Thus, the same threaded fastener  254  may be used in the example of  FIG.  4    that was described above in reference to  FIG.  3   . 
     An advantage to employing the bearing retention plate  300  of the example of  FIG.  4    is that a receiving space  310  is formed between the outer periphery of the second column shaft bearing  242  (which is surrounded by a portion of the bearing retention plate  300 ) and the inner periphery of the lower column casting  216 . The receiving space  310  would allow further travel (and therefore additional impact resistance) for the upper jacket  214  in the event that the upper jacket  214  slides (e.g., telescopically contracting) into the lower column casting  216  during an impact event. 
     To provide resistance to any potential loosening of the threaded fastener  254  of the examples of  FIGS.  3  and  4   , additional retention measures may be taken. In this regard, for example,  FIG.  5 A  shows a cross section view (similar to that of  FIGS.  3 A and  4 A ) with a modified threaded fastener  254 ′.  FIG.  5 B  shows a perspective view of the modified threaded fastener  254 ′ in partial cross section. As shown in  FIGS.  5 A and  5 B , the same structures as those shown in  FIG.  3    may be employed (or those in  FIG.  4   ), except that the modified threaded fastener  254 ′ may be slightly longer than the threaded fastener  254  of  FIGS.  3  and  4   . The modified threaded fastener  254 ′ may also have a radial groove  320  disposed near a distal end thereof. A retaining clip  322  may be placed in the radial groove  320  to prevent withdrawal of the modified threaded fastener  254 ′ from the threaded receiver  250  of the lower steering shaft  218 . 
     Other methods may alternatively be employed to prevent loosening of the threaded fastener  254 .  FIG.  6    illustrates such an example. In this regard,  FIG.  6 A  shows a cross section view (similar to that of  FIGS.  3 A and  4 A ) with a modified opening to the receiving.  FIG.  6 B  shows a perspective view of the threaded fastener  254  in partial cross section. As shown in  FIGS.  6 A and  6 B , the same structures as those shown in  FIG.  3    may be employed (or those in  FIG.  4   ), except that the threaded fastener  254  may be retained from backing out proximate to a head portion of the threaded fastener  254 . For example, rather than placing the radial groove  320  on the outer periphery of the modified threaded fastener  254  of  FIG.  5   , a radial groove  330  may instead be placed at an opening into the receiving hole  252 . The radial groove  330  may have a retaining clip  332  inserted therein to prevent withdrawal of the threaded fastener  254 . 
     The example of  FIG.  7    replaces the threaded fastener  254  entirely. In this regard, instead of having the threaded receiver  250 , the torsion bar  228 ′ of  FIG.  7    includes a multi-lobe engagement structure  340  that is an interference fit via a hard polymer (e.g., HNBR, Durometer 30-95 Shore A) element interface into respective capture slots  342  formed in the lower steering shaft  218 . The lobes of the multi-lobe engagement structure  340  may be equidistantly spaced about a periphery of the torsion bar  228 ′ as shown in  FIGS.  7 B and  7 C , which illustrate perspective views of the multi-lobe engagement structure  340 . Meanwhile,  FIG.  7 A  illustrates a cross section view similar to that of  FIGS.  3 A and  4 A . The torsion bar  228 ′ may be received into the lower steering shaft  218  (and more particularly into the capture slots  342 ) thereof to absorb lash between the column  210  and the feedback actuator  220 . The multi-lobe engagement structure  340  and capture slots  342  of the example of  FIG.  7    may be employed either with the bearing retention plate  300  of the example of  FIG.  4    (as shown in  FIG.  7   ) or without the bearing retention plate  300  and therefore retaining the second column shaft bearing  242  by press fit as shown in the example of  FIG.  3   . 
       FIG.  8    shows an alternative threaded fastener design for implementation of the removable fastener. In this regard,  FIG.  8 A  illustrates a cross section view similar to that of  FIGS.  3 A and  4 A , and  FIG.  8 B  illustrates a perspective view with the plane of the cross section moved off the axis and toward the viewer so that an entirety of a fastener opening  360  is visible. In the example of  FIG.  8    (similar to the example of  FIG.  6   ), a radial groove  362  is placed at the fastener opening  360  into a receiving hole  364  of the lower steering shaft  218 . The radial groove  362  may have a retaining clip  366  inserted therein to prevent withdrawal of a set screw  368 . As noted above, the stub shaft  226  and the lower steering shaft  218  may be mated together via insertion of torsion bar  228 ″ into the lower steering shaft  218 . The lower steering shaft  218  may then be rotated (e.g., via the handwheel  110 ) to align the receiving hole  364  with the access port  230  to insert the set screw  368  through the receiving hole  364  and into a set screw landing zone  370 . The torsion bar  228 ″ includes the set screw landing zone  370  (or landing area) at a similar location to that of the threaded receiver  250  described above, and the set screw landing zone  370  receives the set screw  368  instead of the threaded receiver  250 . The set screw  368  may be inserted into the set screw landing zone  370 , which may have larger tolerance than the threaded receiver  250 . Thus, the set screw  368  may be a relatively easy option to employ, while still providing good performance. As was the case with other examples, the set screw  368  may be employed in connection with use of the bearing retention plate  300  of the example of  FIG.  4    (as shown in  FIG.  8   ) or without the bearing retention plate  300  and therefore retaining the second column shaft bearing  242  by press fit as shown in the example of  FIG.  3   . 
     It may also be possible to employ the strategy of  FIG.  8    except with a different type of retaining clip. For example,  FIG.  9    shows an example in which a radial groove  380  is placed around a periphery of the lower steering shaft  218 , and a retaining clip  382  is placed in the radial groove  380 . As shown in  FIG.  9   , the radial groove  380  is aligned with the location of the receiving hole  364  so that the retaining clip  382  (when inserted) extends around and retains the set screw  368  in place and prevents the set screw  368  from backing out of the receiving hole  364 , thereby maintaining engagement between the torsion bar  228 ″ and the lower steering shaft  218 . However, the example of  FIG.  9    shows an additional modification to prior examples. In particular, a second middle bearing is provided in the example of  FIG.  9   . The second middle bearing (i.e., second feedback actuator bearing  390 ) is actually located in the feedback actuator  210  and supports the stub shaft  226  at a rearward portion thereof. Thus, in the example of  FIG.  9   , the stub shaft  226  is supported both at forward and rearward ends (by the feedback actuator bearing  244  and the second feedback actuator bearing  390 , respectively). Although not required, in some cases a second radial groove  381  may be provided to store the retaining clip  382  during shipment, prior to assembly, or otherwise temporarily when the retaining clip  382  needs to be moved to provide access to the set screw  368 . The second radial groove  381  may be similar to the radial groove  380 , except being offset therefrom axially along the lower steering shaft  218 . 
     Notably, the second feedback actuator bearing  390  may be employed in connection with use of the bearing retention plate  300  of the example of  FIG.  4    (as shown in  FIG.  9   ) or without the bearing retention plate  300  and therefore retaining the second column shaft bearing  242  by press fit as shown in the example of  FIG.  3   . Moreover, the second feedback actuator bearing  390  may be employed in connection with any of the examples shown in  FIGS.  3 - 8    above.  FIG.  9 A  and  FIG.  9 B  show cross section views along the axis of the lower steering shaft  218 , and  FIG.  9 C  shows a perspective view of a cross section with the axis moved toward the viewer. 
     Example embodiments may therefore also include a handwheel actuator for a steer by wire system. The handwheel actuator may include a feedback actuator and a column for operably coupling a handwheel to the handwheel actuator. The column may include a column shaft extending from a first end of the column to a second end of the column. The feedback actuator may be operably coupled to the second end of the column and may provide tactile feedback to an operator responsive to movement of the handwheel. The feedback actuator may include a torsion bar coaxial with the column shaft. The column shaft may be supported relative to a housing of the column by a first column shaft bearing disposed proximate to the first end of the column and a second column shaft bearing disposed proximate to the second end of the column. The torsion bar may extend into the column shaft past the second column shaft bearing and is operably coupled to the column shaft via a removable fastener disposed at a portion of the torsion bar that extends past the second column shaft bearing. 
     The handwheel actuator of some embodiments may include additional features, modifications, augmentations and/or the like to achieve further objectives or enhance performance of the device. The additional features, modifications, augmentations and/or the like may be added in any combination with each other. Below is a list of various additional features, modifications, and augmentations that can each be added individually or in any combination with each other. For example, the second column shaft bearing may be retained in the housing via a press fit. Alternatively, the second column shaft bearing may be retained in a bearing retention plate that is operably coupled to the housing. In an example embodiment, the bearing retention plate may define a receiving space between a portion of the bearing retention plate that surrounds an outer periphery of the second column shaft bearing and an inner periphery of the housing. In some cases, the housing may include an upper jacket and a lower column casting. The upper jacket may be slideable into the receiving space responsive to an impact event. In an example embodiment, the removable fastener may be a threaded fastener, and the column shaft may include a receiving hole disposed proximate the second end of the column and the torsion bar may include a threaded receiver. The threaded fastener may be passed through the receiving hole and the threaded receiver to operably coupled the column shaft to the torsion bar. In some cases, the removable fastener may include a radial groove disposed proximate a distal end thereof, and a retaining clip may be disposed in the radial groove to retain the threaded fastener in the threaded receiver. In an example embodiment, an opening to the receiving hole may include a radial groove, and a retaining clip may be disposed in the radial groove to retain the threaded fastener in the threaded receiver. In some cases, the removable fastener may be a set screw, and the column shaft may include a receiving hole disposed proximate the second end of the column and the torsion bar may include a set screw landing area. The set screw may be passed through the receiving hole to apply torque to the set screw landing area to operably couple the column shaft to the torsion bar. In an example embodiment, an opening to the receiving hole may include a radial groove, and a retaining clip may be disposed in the radial groove to retain the threaded fastener in the threaded receiver. In some cases, a radial groove may be disposed around a periphery of the column shaft proximate to the receiving hole, and a retaining clip may be disposed in the radial groove to retain the threaded fastener in the threaded receiver. In an example embodiment, the feedback actuator may include a stub shaft coaxial with the torsion bar, and the stub shaft may have a torque limiting interface formed with the column shaft to prevent over-application of torque to the torsion bar. In some cases, the stub shaft may be supported in the feedback actuator by a feedback actuator bearing disposed at a distal end of the stub shaft relative to the column shaft. In an example embodiment, the feedback actuator bearing may be the only radial support for the stub shaft in the feedback actuator. Alternatively, a second feedback actuator bearing may be disposed at a proximal end of the stub shaft relative to the column shaft. In an example embodiment, an access port may be disposed at a portion of the housing proximate to the second end of the column, and the removable fastener may be accessible via the access port. In an example embodiment, the access port may have a removable cover. The cover may be removable to provide access to the removable fastener via the access port. In some cases, the column shaft may be rotatable to a first position to insert the removable fastener by aligning a receiver in the torsion bar with the access port, and the column shaft may be rotatable 180 degrees to a second position to insert a retaining clip to prevent withdrawal of the removable fastener. In an example embodiment, the removable fastener may include a multi-lobe engagement structure disposed at a proximal end of the torsion bar relative to the column shaft. In some cases, the column shaft may include a plurality of capture slots corresponding to each respective lobe of the multi-lobe engagement structure. 
     Many modifications and other embodiments of the inventions set forth herein will come to mind to one skilled in the art to which these inventions pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the inventions are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Moreover, although the foregoing descriptions and the associated drawings describe exemplary embodiments in the context of certain exemplary combinations of elements and/or functions, it should be appreciated that different combinations of elements and/or functions may be provided by alternative embodiments without departing from the scope of the appended claims. In this regard, for example, different combinations of elements and/or functions than those explicitly described above are also contemplated as may be set forth in some of the appended claims. In cases where advantages, benefits or solutions to problems are described herein, it should be appreciated that such advantages, benefits and/or solutions may be applicable to some example embodiments, but not necessarily all example embodiments. Thus, any advantages, benefits or solutions described herein should not be thought of as being critical, required or essential to all embodiments or to that which is claimed herein. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.