Patent Abstract:
An automatically variable vehicle ground clearance for motor vehicles with semi-elliptical spring suspensions. A drive member is placed at each wheel corner to be height adjusted, the drive member being motor driven. An operator may select a height preference by operation of a switch, or a controller may provide a range of height selections based upon an algorithm which is responsive to sensed vehicle ride conditions, as for example vehicle speed, to optimize vehicle performance.

Full Description:
TECHNICAL FIELD 
     The present invention relates to manually variable ride height adjustment apparatus for use with semi-elliptical spring suspensions of motor vehicles, and more particularly to an automatically variable ride height adjustment apparatus for use with semi-elliptical spring suspensions. 
     BACKGROUND OF THE INVENTION 
     Ride height adjustment of a motor vehicle equipped with a semi-elliptical spring suspension is accomplished by raising or lowering a distal end of a semi-elliptical spring relative to a suspension attachment member, as for example a control arm. Adjustable ride height allows, on the one hand, the motor vehicle to be lowered relative to the ground to improve aerodynamics and fuel economy, and, on the other hand, raised to clear driveway ramp angles so as to prevent underbody or front end damage in everyday driving. 
     As illustrated in  FIGS. 1 through 2C , a wheel corner  10  features a semi-elliptical spring suspension  12  which includes a manually variable ride height adjustment apparatus  14 . The manually variable ride height adjustment apparatus  14  utilizes a threaded stud  16  with a multi-faced drive head  16   a , wherein stud threads  18  are threadably engaged with a threaded spring collar  20  connected to a distal end  24   e  of the elliptical spring  24  at an aperture  24   a  formed therein. A base  26  of the threaded stud is welded to a pad collar  28  connected with a spring tip pad  30 , which is, in turn, connected to a suspension attachment member  32 , as for example a control arm. 
     In operation of the manually variable ride height adjustment apparatus  14 , to adjust from a medial position of the distal end of the semi-elliptical spring  24  with respect to the suspension attachment member  32  ( FIG. 2A ), a wrench (not shown) is interfaced with the multi-faced drive head  16   a , and the threaded stud  16  rotated: if turned in one direction, the distal end of the elliptical spring  24  is moved away from the suspension attachment member  32 , thereby raising the vehicle with respect to ground level ( FIG. 2B ); whereas, if turned in the opposite direction, the distal end of the elliptical spring is moved closer to the suspension attachment member, thereby lowering the vehicle with respect to ground level ( FIG. 2C ). 
     In the prior art it is known to provide ride height adjustment of motor vehicle suspension utilizing variably pressurized air suspension components, such as for example air springs. An example of air springs is disclosed in U.S. Pat. No. 2,901,241 to Lautzenhiser, et al, and assigned to the assignee hereof. 
     What remains needed in the art is an automatically variable rise height adjustment apparatus for use with semi-elliptical spring suspensions, which, in a particular form, is operatively responsive to vehicle ride conditions. 
     SUMMARY OF THE INVENTION 
     The present invention is an automatically variable rise height adjustment apparatus for use with semi-elliptical spring suspensions which may provide operative response based upon sensed vehicle ride conditions. 
     The automatically variable rise height adjustment apparatus according to the present invention may interface with, and utilize, selected mechanical components of the above described manual variable rise height adjustment apparatus, or may utilize other mechanical components. Generally in this regard, the automatically variable rise height adjustment apparatus includes a drive member composed of a rotatively driven component and at least one stationary component, as for example a stud interconnected with a suspension attachment member, as for example a control arm, and a threaded collar of a semi-elliptical spring interfaced with the threaded stud, wherein one of the threaded stud and the threaded collar is the rotatively driven component and the other is the at least one stationary component. 
     At least one electric motor powered by the vehicle electrical system is connected to the rotatively driven components via drive links, such as for example a flexible drive cables. In this regard, the motor turns the rotatively driven component of each of the front wheel corners via dual drive links, and/or similarly drives the drive members of the rear wheel corners if so equipped. While one motor can drive all the rotatively driven components via respective drive links, a motor allocated, respectively, to each of the front and rear wheel corners allows for front-to-rear level adjustment as well as height (ground clearance) adjustment. 
     The goal of the present invention is to provide automatic selection of vehicle ground clearance for motor vehicles with semi-elliptical spring suspensions, wherein an operator may select a height preference by operation of a switch, or a controller (i.e., computer) may provide a range of height selections based upon an algorithm which is responsive to sensed vehicle ride conditions, as for example vehicle speed, to optimize vehicle performance. For example, an operator may select a favorite vehicle body ride height which is high, medial or low and yet avoids driveway apron scrapping due to steep approach and departure angles. Further for example, a computer may be programmed to lower the vehicle body for a high speed ride condition (by nonlimiting example speeds above about 30 MPH), place the vehicle height at a medial level for a moderate speed ride condition (for nonlimiting condition between about 10 MPH and 30 MPH), and raise the body for a slow speed ride condition (for nonlimiting example below about 10 MPH). Lowering the body relative to the ground to improve aerodynamics and fuel economy at a high speed ride condition by rotating the rotatively driven components so that the semi-elliptical springs are less spaced from the suspension attachment members, and raising the body relative to the ground by rotating the rotatively driven components so that the semi-elliptical springs are more spaced from the suspension attachment members to provide clearance of driveway ramp angles at a slow speed ride condition. 
     Accordingly, it is an object of the present invention to provide an automatically variable rise height adjustment apparatus for use with semi-elliptical spring suspensions which may provide operative response based upon sensed vehicle conditions. 
     This and additional objects, features and advantages of the present invention will become clearer from the following specification of a preferred embodiment. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a partly broken-away, partly sectional front view of a wheel corner featuring a prior art manually variable ride height adjustment apparatus. 
         FIG. 2  is a detail sectional view seen at circle  2  of  FIG. 1 . 
         FIGS. 2A through 2C  are schematic views of height adjustments utilizing the manually variable ride height adjustment apparatus of  FIGS. 1 and 2 . 
         FIG. 3  is a schematic diagram of a semi-elliptical spring suspension equipped with an automatically variable ride height adjustment apparatus according to the present invention. 
         FIG. 4  is a sectional detail side view of a drive member of an automatically variable ride height adjustment apparatus according to a first example of the present invention. 
         FIGS. 4A and 4B  are schematic views of height adjustments utilizing the automatically variable ride height adjustment apparatus of  FIG. 4 . 
         FIG. 5  is a sectional detail side view of a drive member of an automatically variable ride height adjustment apparatus according to a second example of the present invention. 
         FIGS. 5A and 5B  are schematic views of height adjustments utilizing the automatically variable ride height adjustment apparatus of  FIG. 5 . 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to the Drawing,  FIGS. 3 through 5B  depict various aspects of an automatically variable ride height adjustment apparatus  100  according to the present invention. 
     At  FIG. 3 , a motor vehicle  102  has a semi-elliptical spring suspension  104  at each front wheel corner  106   f  and each rear wheel corner  106   r , each including, respectively, a semi-elliptical spring  108  and a suspension attachment member  110 , which may for example be a control arm or other component. A switch  112  is provided for a driver of the vehicle to activate the automatically variable ride height adjustment apparatus  100 , wherein if no controller (computer, electronic control module, etc.) is present, then the switch directly, via control line(s)  112   a , operates the motor(s)  114  of the automatically variable ride height adjustment apparatus, via one or more drive lines  118 , which motor(s) are connected to the drive member  116  of the automatically variable ride height adjustment apparatus at each wheel corner by a drive link  120 , such as for example a flexible drive cable. In the event a pre-programmed controller  122  is provided, the switch  112  merely sets, via a control line  112   b  (control lines  112   a  being absent), the activation status of the automatically variable ride height adjustment apparatus  100 , and sensor(s)  124 , for example a speed sensor, via data line  126 , provides data to the controller which, according to its pre-programmed algorithm, selectively actuates the motor(s)  114  so as to adjust the drive members  116 . 
     While in  FIG. 3  front and rear wheel corners  106   f ,  106   r  each have respective drive members  116 , the drive members may be present only at the front or at the rear wheel corners, and only one motor  114  may be used even if both the front and rear wheel corners have drive members. 
       FIGS. 4 and 5  depict examples of drive members  116  of the automatically variable ride height adjustment apparatus  100 , wherein it is to be understood that other, differently constructed drive members may be utilized by artisans of ordinary skill in the art to provide height adjustment of the semi-elliptical springs relative to the suspension attachment members. 
     As shown at  FIG. 4 , a first example of a drive member  116 ,  116 ′ is depicted which utilizes a double-threaded (i.e., opposed directions of threading) stud  130  having a multi-faced drive head  130   a , wherein a first set of stud threads  132  is threadably engaged with a threaded spring collar  134  which is connected to a distal end  108   e  of the elliptical spring  108 ′ at an aperture  108   a  formed therein, and a second set of stud threads  136  is threadably engaged with a threaded pad collar  138  which is non-rotatably connected with a pad collar  140  of a spring tip pad  142 , which is, in turn, connected to a suspension attachment member  110 ′. The drive head  130   a  is drivingly connected to a driver socket  144  disposed at the terminal end of a drive link  120 ′. A bushing  146  connected to the semi-elliptical spring provides location of the driver socket  144 . 
     Referring now additionally to  FIGS. 4A and 4B , operation of the automatically variable ride height adjustment apparatus  100  with the second example of drive members  116 ′ will be described. 
     To adjust from the medial position of the distal end of the semi-elliptical spring  108 ′ with respect to the suspension attachment member  110 ′ ( FIG. 4 ), the switch  112  or controller  122  actuates at least one motor  114  and drives the drive links  120 ′ so that the driver socket  144  rotates the double-threaded stud  130  with respect to each of the spring collar  134  and the pad collar  138 , whereby rotation in one direction (arrow A of  FIG. 4A ) moves the elliptical spring a farther distance from the suspension attachment member, and rotation in the other direction (arrow B of  FIG. 4B ) causes the elliptical spring to be located a shorter distance from the suspension attachment member. 
     Referring now to  FIG. 5 , a second example of a drive member  116 ,  116 ″ is depicted which utilizes a singly threaded stud  150 , which may be, by way of example, in the form of the aforementioned threaded stud  24  with base  26 . The stud threads  152  are threadably engaged with a threaded drive collar  154  which is rotatably disposed in an aperture  108   a ′ of the elliptical spring  108 ″ at the distal end  108   e ′ thereof. The drive collar  154  is drivingly connected to a terminal end of a drive link  120 ″ which connects to a motor  114 . The threaded stud is rigidly and non-rotatably mounted by welding of the base  156  of the threaded stud  150  to a spring collar  158  of a spring tip pad  156 , which is, in turn, connected to the suspension attachment member  110 ″. 
     Referring now additionally to  FIGS. 5A and 5B , operation of the automatically variable ride height adjustment apparatus  100  with the second example of drive members  116 ″ will be described. 
     To adjust from the medial position of the distal end of the semi-elliptical spring  108 ″ with respect to the suspension attachment member  110 ″ ( FIG. 5 ), the switch  112  or controller  122  actuates at least one motor  114  and drives the drive links  120 ″ so that the drive collar  154  rotates with respect to the threaded stud  150 , whereby rotation in one direction (arrow A′ of  FIG. 5A ) causes the elliptical spring  108 ″ to move a farther distance from the suspension attachment member  110 ″, and rotation in the other direction (arrow B′ of  FIG. 5B ) causes the elliptical spring to be a shorter distance from the suspension attachment member. 
     To those skilled in the art to which this invention appertains, the above described preferred embodiment may be subject to change or modification. Such change or modification can be carried out without departing from the scope of the invention, which is intended to be limited only by the scope of the appended claims.

Technology Classification (CPC): 1