Patent Publication Number: US-2023150565-A1

Title: Auxiliary unstowing mechanism for vehicle steering column

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefits of priority to U.S. Patent Application Ser. No. 63/280,210, filed Nov. 17, 2021, the disclosure of which is incorporated by reference herein in its entirety. 
    
    
     FIELD OF THE INVENTION 
     The embodiments disclosed herein relate to vehicle steering column assemblies and, more particularly, to an auxiliary unstowing mechanism for such assemblies. 
     BACKGROUND 
     Stowable steering column systems for road vehicles are designed to provide increased convenience to the vehicle user by providing more space around the user in certain situations. The column is able to retract the steering wheel toward or into the vehicle dashboard when appropriate. For example, this may be desirable while the vehicle is parked. If the vehicle has the ability to steer itself in one or more driving modes and can also be steered by the user in one or more driving modes, then a stow feature may also be used while the vehicle is driven autonomously or semi-autonomously. 
     Inability to unstow the steering column may arise due to a failure in the system. If the column is unable to unstow, then the user may no longer be able to properly steer the vehicle. It may not be feasible for the user to steer the vehicle because of the extreme position of the steering wheel or the proximity of the steering wheel to the dashboard. Alternatively, the vehicle may not allow the user to rotate the steering wheel while it is in a particular zone within the complete range of motion of the column. If the vehicle is unable to steer itself to the user&#39;s desired destination, the user may need to have the vehicle towed and serviced immediately. The inability of the user to steer the vehicle may be inconvenient to the user. 
     In one example of a power column topology, a first electronic control unit (ECU) controls the telescope motor. In the case of fully stowed condition and during failure of the first ECU or telescoping control failure, the driver is unable to pilot the vehicle. 
     SUMMARY OF THE DISCLOSURE 
     According to one aspect of the disclosure, an auxiliary unstow mechanism for a vehicle steering column includes a telescope actuator assembly. The auxiliary unstow mechanism also includes a first electronic control unit (ECU) in communication with the telescope actuator assembly to control the telescope actuator assembly. The auxiliary unstow mechanism further includes a latch actuator operatively controlling a latch assembly that controls a locked condition and an unlocked condition of vehicle steering column axial position. The auxiliary unstow mechanism yet further includes a second ECU in communication with the first ECU and the latch actuator, the second ECU controlling the latch actuator. 
     According to another aspect of the disclosure, a method of unstowing a vehicle steering column is provided. The method includes operating a telescope actuator assembly with a first electronic control unit (ECU). The method also includes operating a latch actuator with a second ECU. The method further includes monitoring the first ECU for a failure condition of the first ECU and/or the telescope mechanism with the second ECU. 
     These and other advantages and features will become more apparent from the following description taken in conjunction with the drawings. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The subject matter that is regarded as the subject invention is particularly pointed out and distinctly claimed in the claims at the conclusion of this specification. The foregoing and other features and advantages of the invention are apparent from the following detailed description of non-limiting exemplary embodiments of the invention taken in conjunction with the accompanying drawing thereof in which: 
         FIG.  1    is a schematic illustration of a steering column assembly having an auxiliary unstowing mechanism; 
         FIG.  2    is an elevational view of the steering column assembly; 
         FIG.  3    is a sectional view of a portion of the steering column assembly; 
         FIG.  4    is a schematic illustration of an auxiliary unstowing mechanism for the steering column assembly; 
         FIG.  5    is a schematic illustration of the auxiliary unstowing mechanism according to another aspect of the disclosure; and 
         FIG.  6    is a flow diagram for operation of the auxiliary unstowing mechanism for the steering column assembly. 
     
    
    
     DETAILED DESCRIPTION 
     Referring now to the Figures, where the invention will be described with reference to specific embodiments, without limiting same,  FIG.  1    illustrates a steering column assembly  20 . The steering column assembly  20  facilitates translation of a steering wheel (not shown) and a steering shaft  26  in a retractable manner. This is particularly beneficial in embodiments where the assembly  20  is employed in a passenger vehicle equipped with Advanced Driver Assist System(s) (ADAS) to allow the vehicle to be autonomously, or semi-autonomously, controlled using sensing, steering, and/or braking technology. When the ADAS is activated, the steering wheel is not required for vehicle control in some situations. Retraction of the steering wheel and steering shaft  26  toward, and possibly into, the instrument cluster greatly enhances user comfort by providing a driver with more space. The additional space provided facilitates additional workspace area or leg room, for example. 
     The embodiments described herein provide a retractable steering column which allows the steering wheel to be retracted while the vehicle is in an autonomous, or semi-autonomous, driving mode, and methods associated with monitoring and adjusting the steering column assembly  20 . Retraction of the steering column assembly  20  (and steering wheel) toward, and possibly into, the instrument panel may be referred to as a “stowed” position or condition, while extension of the steering column assembly  20  to a range of positions that allow an operator to manually steer the vehicle may be referred to as an “unstowed” position or condition. While the steering column assembly  20  may be in the stowed position in the autonomous or semi-autonomous driving modes, other conditions for a stowed steering column assembly  20  are also contemplated. For example, a parked vehicle may allow the steering column assembly  20  to be positioned in the stowed position. 
     An electric motor  48  of a telescope actuator assembly  22  at least partially retracts the steering column assembly  20  into the instrument panel of the vehicle and extends the steering column assembly  20  therefrom. However, the embodiments described herein allow manual adjustment under certain circumstances, as described herein. 
     Extension and retraction of the steering column assembly  20  refers to translation of a retractable portion  28  of the steering column assembly  20 . The retractable portion  28  includes one or more components that are translatable. For example, in addition to the aforementioned steering wheel and the steering shaft  26 , a moveable portion, which may also be referred to as an upper jacket  28  in some embodiments, is translatable relative to a stationary portion  24 , which may be referred to as a lower jacket in some embodiments. Also shown is a mounting bracket  25  that couples the steering column assembly  20  to the vehicle. In other embodiments, more or fewer than two jackets are provided. 
       FIGS.  2  and  3    illustrate an embodiment of features of the telescope actuator assembly  22  that facilitates adjustment of the steering column assembly  20 . Multiple embodiments of a clutch device and nut are described in detail in U.S. patent application Ser. No. 15/628,836, which is incorporated by reference herein its entirety.  FIGS.  2  and  3    illustrate an example of such features, but it is to be appreciated that the embodiments described herein are applicable to any powered steering column that allows manual adjustment thereof in some conditions, with such conditions defined herein. 
       FIGS.  2  and  3    illustrate a screw or threaded rod  44 , a shuttle assembly  46 , and the electric motor  48 . The shuttle assembly  46  may include a shuttle  47  and a clutch device  58  that may be directly supported by and engaged to the shuttle  47 , or a casing  56  of the shuttle  47 . 
     The shuttle  47  of the shuttle assembly  46  may be mounted between the screw  44  and an E/A strap  29 . More specifically, the shuttle assembly  46  is threadably mounted to the screw  44  for axial translation along the screw, and may be rigidly fixed to the E/A strap  29 . In operation and when the electric motor  48  is rotating the screw  44 , the shuttle assembly  46  axially translates along the rotating screw  44 . During this axial translation, the rearward shaft portion  32  of the steering shaft  26  and the upper jacket  28  is carried by, and with, the shuttle assembly  46 . 
     The shuttle assembly  46  may further include a nut or fixture  50 , at least one bearing  52 , at least one resilient member  54  (e.g., a coiled spring or a disc spring), and the casing  56 . The screw  44  may be mounted for rotation to the lower jacket  24  and about a centerline  59 , may not be mounted for axial translation along the lower jacket  24 , and is rotatably driven by the electric motor  48  that may be rigidly mounted to the fixed lower jacket  24 . The centerline  59  may be spaced from, and substantially parallel to, the axis  42 . 
     The clutch device  58  may be mounted to the casing  56  and facilitates rotational decoupling of the nut  50  from the casing  56  (and/or shuttle  47 ). The clutch device  58  may include an electric servo  60  and a bolt  62 . The servo  60  may be mounted to an exterior of the casing  56  and functions to move the bolt  62  into and out of at least one recess  64  defined by an external and circumferentially continuous surface of the nut  50 . In one example, the recesses  64  may be axially extending grooves. The clutch device  58 , including the electric servo  60  and the bolt  62  may be collectively referred to herein as a “latch” or “latch assembly”, referenced with numeral  80 . 
     In the present example, the casing  56  may be an integral part of the shuttle assembly  46  (i.e., one-piece), and thus axially translates with the shuttle assembly  46 . The nut  50 , the bearings  52 , and the spring  54  may be mounted to the screw  44  inside the casing  56 . The nut  50  is threaded to the screw  44  such that rotation of the screw  44  about centerline  59  causes the casing  56  and shuttle assembly  46  to axially translate along the screw  44 . A first bearing  52  may be axially located between a first spring  54  and a forward end (i.e. annular face) of the nut  50 . A second bearing  52  may be axially located between a second spring  54  and a rearward end of the nut  50 . 
     In operation and when the steering column assembly  20  is in the powered state and the clutch device  58  is engaged, the forward and rearward bearings  52  minimize any friction produced between the springs  54  and the respective ends of the nut. The axial forces produced by the torque placed upon the screw  44  by the electric motor  48  when in the powered state are not sufficient to overcome the compressive force of the springs  54  (i.e., the springs do not compress axially). 
     When the steering column assembly  20  is in the decoupled state (i.e., not powered by the electric motor  48 , the clutch device  58  is not engaged (i.e., the servo  60  is de-energized). A manual axial force produced by the driver to axially extend and or retract the steering column assembly  20  may cause the nut  50  to free-wheel (i.e., back spin) upon the, now stationary, screw  44  enabling the shuttle assembly  46  to axially translate. 
     The embodiments disclosed herein provide a steering column system that allows a user to steer the vehicle even after a failure of the steering column&#39;s telescoping mechanism. The embodiments disclosed herein provide an alternative way to unstow the steering column and do not require a functioning telescope actuator or its related wire harness, controller, power supply, or communication bus. 
     Referring to  FIG.  4   , the steering input device  42  is shown in a stowed or partially stowed position. The axial movement—or telescoping movement—is facilitated by the telescope actuator assembly  22 . The telescope actuator assembly  22  is controlled, at least partially, by a first ECU (ECU 1 ). The embodiments disclosed herein include a second ECU (ECU 2 ) that is in wired or wireless communication with the first ECU. The second ECU powers and controls the latch assembly  80 . The latch actuator  60  allows for release of the latch  80  that would otherwise prevent telescope movement of the steering column assembly  20 . In other words, the latch actuator  60  controls whether the latch  80  is engaged or disengaged. In some embodiments, the latch actuator  60  is a motor, but other types of actuators are contemplated. In the engaged position, the steering column assembly  20  is locked in the stowed position—or partially stowed position. In the disengaged position, the steering column assembly  20  may be moved to the unstowed position. In some embodiments, the latch actuator  60  controls the bolt  62  that engages with the nut  50  of the clutch device  58 . 
     The second ECU monitors the condition of the first ECU with one or more signals and is capable of detecting failure of the telescoping mechanism  22  or the first ECU while the steering column assembly  20  is stowed, partially stowed. During the failure, the second ECU allows latch functionality via the latch actuator  60 , so the user can unstow and steer the vehicle. Inability to unstow may arise due to a failure of one or more parts of the electromechanical system (e.g., telescope actuator assembly  22 ) that is required to perform the unstow operation. Examples of such parts include the telescope electric motor  48 , the ECU that controls the telescope motor (ECU 1 ), the battery that powers ECU 1 , a wire harness, and/or a gear. 
       FIG.  5    illustrates an embodiment having the second ECU in direct communication (wired or wireless) with the telescope actuator assembly  22  in addition to the first ECU. This provides the capability of the second ECU to directly monitor the telescope actuator assembly  22  and the first ECU for a failure condition of either the telescope actuator assembly  22  or the first ECU. 
     As described above, the stow feature may be used while the vehicle is parked or while a high-level automated driving feature is engaged (e.g., autonomous or semi-autonomous driving modes). 
     Referring now to  FIG.  6   , a method of providing auxiliary unstow capability for the steering column is illustrated by way of the flow diagram. In particular, the ECU (e.g., ECU 2 ) that controls the latch actuator  60  receives a signal from the telescoping control ECU (e.g., ECU 1 ) to evaluate whether latch control should be active or not. 
     While the invention has been described in detail in connection with only a limited number of exemplary embodiments, it should be appreciated that the invention is not limited to such embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions, or equivalent arrangements not heretofore described, but that are commensurate with the spirit and scope of the invention. Additionally, while various non-limiting exemplary embodiments of the invention have been described, it should be appreciated that aspects of the invention may include only some of these embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description.