Abstract:
A disconnectible stabilizer bar assembly for a vehicle having first and second stabilizer bar halves, a housing fixed to an end portion of each stabilizer bar half, so as to align the two halves. The housing containing a stator with magnetic coil, a rotor with exterior magnets and threaded onto a hollow screw, with the stator selectively rotating the rotor and the rotation translated into axial movement of the screw. The screw having meshing means on an interior surface and an end face, the interior meshing means meshed with an exterior meshing means on one of the stabilizer bar halves, and the end face meshing means selectively coupled and decoupled with aligned mashing means on the other of the stabilizer bar halves.

Description:
FIELD OF INVENTION 
       [0001]    The present invention relates to a disconnectible anti-roll suspension system for a vehicle. 
       BACKGROUND 
       [0002]    Vehicle suspension systems often include springs to support a portion of a vehicle, enable all of the vehicle wheels to maintain contact with the ground when travelling over uneven terrain, and isolate occupants of the vehicle from transmission of forces as a result of travel over the uneven terrain. When a vehicle turns, it is known that centrifugal forces acting on the wheel tend to cause the spring supported portion of the vehicle to roll, redistributing weight of the vehicle away from one or more of the vehicle&#39;s wheels. This redistribution may cause instability and may impede the ability of a driver to control the vehicle. Stabilizer bars or control devices interconnecting two wheels of the vehicle are used to resist the vehicle&#39;s tendency to roll in response to centrifugal forces. 
         [0003]    Stabilizer bars reduce roll, however, a known drawback of using a stabilizer bar is that shock is transmitted from one wheel to another. For example, if a vehicle wheel were to strike a bump, that upward force would then be “copied” or imparted through the stabilizer bar to the opposite wheel, causing the opposite wheel to move in an upward direction. This “cross-talk” (i.e. jounce) between the vehicle wheels is undesirable, as it adversely affects vehicle ride. 
         [0004]    In tuning the ride and handling of a vehicle, it is often desirable to soften or lower the spring rate of the suspension spring&#39;s to provide a softer, less harsh ride. Lowering the spring rate, however, permits the vehicle body to roll at a relatively higher rate. Accordingly, it would seem that the combination of springs with a very low spring rate and a relatively stiff stabilizer bar would optimize both the ride and handling of the vehicle. 
         [0005]    Actively actuated, halved stabilizer bars or control systems are intended to provide the benefit of reduction or control of roll in the connected state, and reduction or elimination of “cross-talk” or force transmission between wheels in the disconnected state. A pair of independently mounted stabilizer bar halves that can be selectively de-coupled from one another are known, for example in U.S. Pat. Nos. 7,837,202 (hereinafter referred to as the &#39;202 patent) and 7,909,339 (hereinafter referred to as the &#39;339 patent). 
       SUMMARY OF THE INVENTION 
       [0006]    Certain terminology is used in the following description for convenience and descriptive purposes only, and is not intended to be limiting to the scope of the claims. The terminology includes the words specifically noted, derivatives thereof and words of similar import. 
         [0007]    According to an example embodiment of the present invention, a vehicle suspension system, particularly an anti-roll suspension, includes a pair of independently mounted stabilizer bar halves that can be selectively coupled or de-coupled from one another. A electric motor stator energizes magnets as a result of an external electrical signal, consequently rotating a rotor with internal threading. An associated hollow screw with external threading meshing with the internal threading of the rotor, and internal splines meshing with external splines of an associated stabilizer bar half, translates said rotation into axial motion of the hollow screw, engaging integral jaws or teeth on an end face of the screw with jaws or teeth integrally formed or fixed to and end face of a second stabilize bar half, thus coupling the two stabilizer bar halves. The torque resulting from an upward force on an associated wheel, directed through a stabilizer bar half can then be translated through the meshing jaws of the rotor and stabilizer bar half, and through the meshing splines of the rotor and other stabilizer bar half 
         [0008]    The above mentioned and other features and advantages of the embodiments described herein, and the manner of attaining them, will become apparent and be better understood by reference to the following description of at least one example embodiment in conjunction with the accompanying drawings. A brief description of those drawings now follows. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0009]      FIG. 1  is a perspective exploded assembly view of a disconnectible stabilizer bar assembly according to one embodiment of the invention. 
           [0010]      FIG. 2  is a cross sectional view of disconnectible stabilizer bar actuator assembly in the fully assembled state, according to one embodiment of the invention. 
           [0011]      FIG. 3  is a cross-sectional perspective view of an actuator assembly of a disconnectible stabilizer bar, according to one embodiment of the invention. 
           [0012]      FIG. 4  is a another cross-sectional view of the actuator assembly of  FIG. 3 . 
           [0013]      FIG. 5  is perspective exploded assembly view of the actuator assembly of the stabilizer bar assembly of  FIG. 1 . 
           [0014]      FIG. 6  is a cross sectional view of the actuator assembly of  FIG. 3 , taken along line A-A. 
           [0015]      FIG. 7  is a top view of front and rear wheels of a drivetrain of a vehicle incorporating the disconnectible stabilizer bar assembly, according to one example embodiment of the inevntion. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0016]    Identically labeled elements appearing in different ones of the figures refer to the same elements but may not be referenced in the description for all figures. The exemplification set out herein illustrates at least one embodiment, in at least one form, and such exemplification is not to be construed as limiting the scope of the claims in any manner. 
         [0017]      FIG. 1  shows a perspective exploded assembly view of disconnectible stabilizer bar assembly  1  according to one example embodiment of the invention. Stabilizer bar half  2  is an L-shaped curved bar which is formed according to the needs of a particular application, and includes a wheel linkage end  30  for connection to a wheel (see  FIG. 7 ) of an associated vehicle (not shown), and a splined end  32 , with integrally formed or machined splines  4 . A second stabilizer bar half  3 , is an L-shaped curved bar, including a wheel linkage end  34  and a coupling end  36 , onto which fixed coupling slide  17  with integrally formed jaws  18 , can be fixedly assembled. Alternatively, jaws  18  can be integrally formed or machined on end  36  of bar half  3 . As will be understood by one of ordinary skill in the art, bar halves  2  and  3  can be of different forms, cross sections and configurations suitable for a particular vehicle application, and are thus not limited by the depiction shown in this example embodiment. 
         [0018]    Actuator assembly  50  is assembled between splined end  32  of bar  2  and coupling end  36  of bar  3 . Actuator assembly  50  comprises bushing  5  pressed or otherwise assembled onto end  32  of bar  2 , with housing clamp half  7  assembled onto an outer diameter of bushing  5 . Internal splines  38  (see  FIGS. 2 and 4 ) of hollow screw  9  are slideably meshed with splines  4  of bar  2 , and hollow screw  9  is abutted to an axial retention face  40  of housing clamp  7 , on an end opposite jaws  42 . Bearings  10  are assembled on bearing shelves  44 , axially abutting an end face  46  on opposite axial ends of rotor  12 , and internal thread  13  is threadingly engaged with external thread  11  of hollow screw  9 , with bearing  10  abutting a lip  48  on housing clamp  7 . Electric motor winding  15  is then slideably assembled on an outside diameter of rotor  12 , abutting an end face of housing clamp  7 , and housing  19  is then, in turn, assembled on an outside diameter of winding  15 , until it abuts axial end face  54  of clamp  7  and fasteners  23  are inserted through holes  56  and securely fastened into holes  20  in housing  19 . In turn, bushing  27  is assembled onto end  36  of bar  3 , and housing clamp half  21  assembled onto an outer diameter of bushing  27 . Fixed coupling slide  17  is assembled onto end  36  of bar  3 , until an end opposite jaws  18  abuts an axial retention face  52  of clamp  21  (see  FIG. 4 ). Finally, housing clamp  21  and bar  3 , with associated assembled components are abutted to an end face of housing  19 , and fasteners  25  are inserted through holes  22 , and securely fastened into holes  20  of housing  19 , thus firmly clamping the assembly into one unit. 
         [0019]      FIG. 2  shows a cross sectional assembly view of disconnectible stabilizer bar  1  and actuator assembly  50 , including wheel linkage ends  30  and  34 , of stabilizer bars  2  and  3 , respectively. A cross sectional view of actuator assembly  50  is described in greater detail in  FIGS. 3 and 4 . 
         [0020]      FIGS. 3 and 4  show a cross sectional assembly view of disconnectible stabilizer bar  1  and actuator assembly  50 , comprising stabilizer bar half  2  with external splines  4 , stabilizer bar half  3 , bushing  5 , hollow screw  9  with internal splines  38  and external thread  11 , housing clamp half  7  (including axial retention face  40 , axial end face  54  and bearing lip  48 ), bearings  10 , rotor  12  with internal thread  13 , magnets  14  and bearing shelves  44 , stator winding  15 , housing  19 , housing clamp  21 , fasteners  25 , and fixed coupling slide  17  with jaws  18 . 
         [0021]      FIG. 5  shows a perspective exploded assembly view of actuator assembly  50  of stabilizer bar  1  of  FIG. 1 .  FIG. 6  shows a cross sectional perspective exploded assembly view of  FIG. 5 , taken along line A-A. All the features are as previously described in  FIGS. 1-5 , with a more detailed view of internal splines  38  and jaws  42  of hollow screw  9 , internal threads  13  of rotor  12 , fastener holes  56  of housing clamp  7 , fastener holes  20  of housing  19 , fastener holes  22  of housing clamp  21 , jaws  18  of fixed coupling slide  17 , and external splines  4  of stabilizer bar half  2 . 
         [0022]      FIG. 7  is a top view of a drivetrain of a vehicle. Front wheels  100 ,  101  are connected to stabilizer bar halves  2  and  3 , respectively, is provided with a wheel speed sensor, in turn connected to an engine control unit (ECU), not shown, to measure and monitor wheel speed. Also shown is a steering control unit  110 , linked to wheels  100 ,  101  at each end, respectively, allowing a driver of the vehicle to control wheel and vehicle direction. In addition, the ECU can be connected to a steering angle sensor (not shown), to measure and monitor steering angle of a steering wheel, a sensor to measure acceleration of the vehicle (not shown), a lateral acceleration sensor for measuring and monitoring lateral acceleration, among other sensors to measure vehicle speed, movement and driving characteristics. The ECU also generally includes control units, including a steering control unit  110 , brake control unit (not shown) and stabilizer control unit (not shown), among other control units, in order to adjust vehicle driving parameters based on the measurements of the previously described sensors and control parameters. 
         [0023]    Similarly, a second disconnectible stabilizer bar  1 ′ is connected to each of rear wheels  102 ,  103  and functions the same as stabilizer bar  1 , described above. Preferably, stabilizer bars  1  and  1 ′ will connect and disconnect simultaneously. 
         [0024]    When indicated by programming characteristics input into the ECU and based on the measurements obtained from the various sensors, the ECU provides an input signal to actuator assembly(ies)  50 ,  50 ′ of stabilizer bar assembly(ies)  1 ,  1 ′ to selectively connect or disconnect stabilizer bar halves  2 ,  2 ′ and  3 ,  3 ′, respectively. 
         [0025]    To disconnect stabilizer bar halves  2  and  3 , stator windings  15  are energized in order to activate magnets  14  such that rotor  12 , fixedly associated with magnets  14 , rotates, supported by bearings  10 , in a direction such that meshed threads  13  of rotor  12  and  11  of hollow screw  9  will translate the rotational movement into axial movement of hollow screw  9  along splines  4  of stabilizer bar half  2 , toward stabilizer bar half  2 , until stopped by axial retention face  40  of housing clamp  7 . In this manner jaws  42  of hollow screw  9  will disengage from jaws  18  of fixed coupling slide  17 , disconnecting stabilizer bar half  2  from stabilizer bar half  3 , allowing for independent movement of each stabilizer bar half 
         [0026]    To connect stabilizer bar halves  2  and  3 , the reverse operation is performed from that described in the foregoing paragraph. Namely, a signal is sent to actuator assembly  50 , energizing stator winding  15 , and activating magnets  14  such that rotor  12 , fixedly associated with magnets  14 , rotates in a direction such that meshed threads  13  and  11  translate said rotation into axial movement of hollow screw  9  toward stabilizer bar half  3 , until jaws  42  of screw  9  and jaws  18  of slide  17  mesh. Forces transmitted through the meshed connection of jaws  42  and  18 , are transmitted through internal splines  38  of screw  9 , and external splines  4  of bar half  2 , into staibilizer bar  2 . 
         [0027]    In the foregoing description, example embodiments are described. The specification and drawings are accordingly to be regarded in an illustrative rather than in a restrictive sense. It will, however, be evident that various modifications and changes may be made thereto, without departing from the broader spirit and scope of the present invention. 
         [0028]    In addition, it should be understood that the figures illustrated in the attachments, which highlight the functionality and advantages of the example embodiments, are presented for example purposes only. The architecture or construction of example embodiments described herein is sufficiently flexible and configurable, such that it may be utilized (and navigated) in ways other than that shown in the accompanying figures. 
         [0029]    Although example embodiments have been described herein, many additional modifications and variations would be apparent to those skilled in the art. It is therefore to be understood that this invention may be practiced otherwise than as specifically described. Thus, the present example embodiments should be considered in all respects as illustrative and not restrictive. 
       LIST OF REFERENCE SYMBOLS 
       [0000]    
       
           1  Disconnectible Stabilizer Bar Assembly 
           2  Stabilizer Bar Half (with integral splines) 
           3  Stabilizer Bar Half 
           4  Stabilizer Bar Splines 
           5  Bushing 
           7  Housing Clamp Half 
           9  Hollow Screw 
           10  Bearing 
           11  External Thread 
           12  Electric Motor Rotor 
           13  Internal Thread 
           14  Magnets 
           15  Stator Winding 
           17  Fixed Coupling Slide 
           18  Jaws or Teeth 
           19  Housing 
           20  Fastener Holes 
           21  Housing Clamp Half 
           22  Fastener Recess 
           23  Fasteners 
           25  Fasteners 
           27  Bushing 
           30  Wheel Linkage End 
           32  Spline End 
           34  Wheel Linkage End 
           36  Coupling End 
           38  Screw Internal Splines 
           40  Axial Retention Face 
           42  Jaws 
           44  Bearing Shelf 
           46  End Face 
           48  Bearing Lip 
           50  Actuator Assembly 
           52  Axial Retention Face 
           54  Axial End Face 
           56  Holes 
           100 , 101  Wheels 
           110  Steering Control Unit