PATENT DOCUMENT

Publication Number: US-11173766-B1
Application Number: US-201816106056-A
Country: US
Kind Code: B1

Title: Suspension system with locking structure

Abstract:
A suspension component includes a suspension spring, a screw actuator that is operable to compress and decompress the suspension spring upon supply of electrical power to the screw actuator, and locking structure that engages a portion of the screw actuator to restrain motion of the screw actuator to maintain a current degree of compression of the suspension spring.

Claims:
What is claimed is: 
     
       1. A suspension component, comprising:
 a suspension spring; 
 a screw actuator that is operable to compress and decompress the suspension spring upon supply of electrical power to the screw actuator; and 
 a locking structure that engages a portion of the screw actuator to restrain motion of the screw actuator to maintain a current degree of compression of the suspension spring. 
 
     
     
       2. The suspension component of  claim 1 , further comprising:
 a top mount; 
 a bottom mount; 
 a housing connected to the top mount; 
 and a spring mount connected to the housing, 
 wherein the suspension spring extends from the spring mount to the bottom mount, 
 wherein the screw actuator includes a rotor, a stator that is operable to rotate the rotor as a result of electromagnetic interaction between the stator and the rotor, a shaft that is connected to the bottom mount, and a ball nut that is connected to the rotor and engages the shaft to linearly translate the shaft in response to rotation of the ball nut. 
 
     
     
       3. The suspension component of  claim 1 , wherein the suspension spring extends in an axial direction and the screw actuator extends in the axial direction. 
     
     
       4. The suspension component of  claim 1 , wherein the screw actuator includes a rotatable component, and the locking structure restrains motion of the screw actuator by engagement with the rotatable component. 
     
     
       5. The suspension component of  claim 4 , wherein the locking structure includes a pin that is engageable with a recess formed on the rotatable component. 
     
     
       6. The suspension component of  claim 4 , wherein the locking structure includes a pawl that is engageable with a feature formed on the rotatable component. 
     
     
       7. The suspension component of  claim 4 , wherein the locking structure includes a restraining collar that is engageable with features that are formed on an outer surface of the rotatable component. 
     
     
       8. The suspension component of  claim 4 , wherein the locking structure includes a restraining plate that has recesses that are engageable with features formed on an axial end of the rotatable component. 
     
     
       9. The suspension component of  claim 4 , wherein the rotatable component is a rotor of the screw actuator. 
     
     
       10. The suspension component of  claim 4 , wherein the screw actuator includes a shaft and a nut, wherein the rotatable component is the nut. 
     
     
       11. The suspension component of  claim 4 , wherein the screw actuator is a ball screw actuator. 
     
     
       12. The suspension component of  claim 4 , wherein the screw actuator is a lead screw actuator. 
     
     
       13. The suspension component of  claim 4 , wherein the locking structure is operable to maintain the current degree of compression of the suspension spring when supply of electrical power to the screw actuator is discontinued. 
     
     
       14. A suspension component, comprising:
 suspension spring; 
 a screw actuator that is operable to compress and decompress the suspension spring upon supply of electrical power to the screw actuator, wherein the screw actuator includes a rotatable component and a shaft; and 
 a locking structure that is movable between a disengaged position in which the locking structure does not restrain motion of the rotatable component of the screw actuator, and an engaged position in which the locking structure restrains motion of the rotatable component of the screw actuator to maintain a current degree of compression of the suspension spring. 
 
     
     
       15. The suspension component of  claim 14 , wherein the locking structure restrains motion of the screw actuator by engagement with features that are formed on an axial end of the rotatable component. 
     
     
       16. The suspension component of  claim 14 , wherein the locking structure is operable to maintain the current degree of compression of the suspension spring when supply of electrical power to the screw actuator is discontinued. 
     
     
       17. The suspension component of  claim 14 , further comprising:
 a top mount; 
 a bottom mount; 
 a housing connected to the top mount; and 
 a spring mount connected to the housing, 
 wherein the suspension spring extends from the spring mount to the bottom mount, and 
 wherein the shaft of the screw actuator is connected to the bottom mount to move the bottom mount relative to the top mount in response to translation of the shaft by the screw actuator. 
 
     
     
       18. A suspension component, comprising:
 a top mount; 
 a bottom mount; 
 a housing connected to the top mount; 
 a spring mount connected to the housing; 
 a suspension spring that extends from the spring mount to the bottom mount; 
 a screw actuator that includes a rotor, a stator that is operable to rotate the rotor as a result of electromagnetic interaction between the stator and the rotor, a shaft that is connected to the bottom mount, and a ball nut that is connected to the rotor and engages the shaft to linearly translate the shaft in response to rotation of the ball nut, and is operable to compress and decompress the suspension spring upon supply of electrical power to the screw actuator; and 
 a locking structure that restrains rotation of the rotor of the screw actuator in an engaged position and does not restrain rotation of the rotor of the screw actuator in a disengaged position, wherein the locking structure is configured to maintain a current degree of compression of the suspension spring in the engaged position. 
 
     
     
       19. The suspension component of  claim 18 , wherein the locking structure restrains rotation of the rotor of the screw actuator by engagement with a rotatable component of the screw actuator that is connected to the rotor. 
     
     
       20. The suspension component of  claim 19 , wherein the locking structure includes a restraining plate that has recesses that are engageable with features formed on an axial end of the rotatable component. 
     
     
       21. The suspension component of  claim 18 , wherein the locking structure is operable to maintain the current degree of compression of the suspension spring when supply of electrical power to the screw actuator is discontinued.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 62/555,108, filed on Sep. 7, 2017, the content of which is hereby incorporated by reference in its entirety for all purposes. 
    
    
     TECHNICAL FIELD 
     This disclosure relates to vehicles and, in particular, suspension systems thereof. 
     BACKGROUND 
     Active suspension actuators can change the ride height of a vehicle. By continuous operation of the active suspension actuator, a particular height can be maintained. 
     SUMMARY 
     One aspect of the disclosed embodiments is a suspension component that includes a suspension spring, a screw actuator that is operable to compress and decompress the suspension spring upon supply of electrical power to the screw actuator, and locking structure that engages a portion of the screw actuator to restrain motion of the screw actuator to maintain a current degree of compression of the suspension spring. 
     In some implementations, the screw actuator includes a rotatable component, and the locking structure restrains motion of the screw actuator by engagement with the rotatable component. In one example, the locking structure includes a pin that is engageable with a recess formed on the rotatable component. In another example, the locking structure includes a pawl that is engageable with a feature formed on the rotatable component. In another example, the locking structure includes a restraining collar that is engageable with features that are formed on an outer surface of the rotatable component. In another example, the locking structure includes a restraining plate that has recesses that are engageable with features formed on an axial end of the rotatable component. 
     In some implementations, the rotatable component is a rotor of the screw actuator. In some implementations, the screw actuator includes a shaft and a nut, wherein the rotatable component is the nut. In some implementations, the screw actuator is a ball screw actuator. In some implementations, the screw actuator is a lead screw actuator. 
     The locking structure may be operable to maintain the current degree of compression of the suspension spring when supply of electrical power to the screw actuator is discontinued. 
     In some implementations, the suspension component includes a top mount, a bottom mount, a housing connected to the top mount, a spring mount connected to the housing, and a suspension spring that extends from the spring mount to the bottom mount, wherein the screw actuator includes a rotor, a stator that is operable to rotate the stator as a result of electromagnetic interaction between the stator and the rotor, a shaft that is connected to the bottom mount, and a nut that is connected to the rotor and engages the shaft to linearly translate the shaft in response to rotation of the ball nut. 
     Another aspect of the disclosed embodiments is a suspension component that includes a suspension spring, a linear output actuator that is operable to compress and decompress the suspension spring upon supply of electrical power to the linear output actuator, and a locking structure that engages a portion of the linear output actuator to restrain motion of the linear output actuator to maintain a current degree of compression of the suspension spring. 
     In some implementations, the linear output actuator includes a translatable shaft, and the locking structure restrains motion of the linear output actuator by engagement with the translatable shaft. In one example, the locking structure includes a clamp. In one example, the locking structure is operable to maintain the current degree of compression of the suspension spring when supply of electrical power to the linear output actuator is discontinued. 
     In some implementations, the suspension component includes a top mount, a bottom mount, a housing connected to the top mount, a spring mount connected to the housing, and a suspension spring that extends from the spring mount to the bottom mount, wherein the linear output actuator includes a shaft that is connected to the bottom mount to move the bottom mount relative to the top mount in response to translation of the shaft by the linear output actuator. 
     Another aspect of the disclosed embodiments is a method for operating a vehicle. The method includes detecting a planned stop; moving the vehicle from a raised position to a lowered position while the vehicle is in motion; stopping the vehicle; resuming motion of the vehicle; and moving the vehicle from the lowered position to the raised position subsequent to resuming motion of the vehicle. 
     In some implementations, moving the vehicle from the raised position to the lowered position and from the lowered position to the raised position is performed using suspension components. In some implementations, the suspension components each include a first load path having a passive suspension component, a second load path having an active suspension component, and a locking structure for maintaining compression of the passive suspension component while the vehicle is stopped. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram showing a vehicle according to an example. 
         FIG. 2  is a schematic view of the vehicle of  FIG. 1 . 
         FIG. 3A  is a cross-sectional view of the suspension component at a first length. 
         FIG. 3B  is a cross-sectional view of the suspension component at a second length. 
         FIG. 4A  is a schematic illustration showing a first example of a locking structure in a pre-engaged position relative to a rotational component. 
         FIG. 4B  is a schematic illustration showing the locking structure of  FIG. 4A  in an engaged position relative to the rotational component. 
         FIG. 4C  is a schematic illustration showing the locking structure of  FIG. 4A  in a disengaged position relative to the rotational component. 
         FIG. 4D  is a schematic illustration showing the locking structure of  FIG. 4A  in a released position relative to the rotational component. 
         FIG. 5A  is a schematic illustration showing a second example of a locking structure in a disengaged position relative to a rotational component. 
         FIG. 5B  is a schematic illustration showing the locking structure of  FIG. 5A  in an engaged position relative to the rotational component. 
         FIG. 6A  is a schematic illustration showing a third example of a locking structure in a disengaged position relative to a rotational component. 
         FIG. 6B  is a schematic illustration showing the locking structure of  FIG. 6A  in an engaged position relative to the rotational component. 
         FIG. 7A  is a schematic illustration showing a fourth example of a locking structure and a rotational component. 
         FIG. 7B  is a schematic illustration showing the rotational component of  FIG. 7A . 
         FIG. 8A  is a schematic illustration showing a fifth example of a locking structure in a disengaged position relative to a translational component. 
         FIG. 8B  is a schematic illustration showing the locking structure of  FIG. 8A  in an engaged position relative to the translational component. 
         FIG. 9A  shows the vehicle in a raised position. 
         FIG. 9B  shows the vehicle in a lowered position. 
         FIG. 10  is a schematic view of a controller. 
         FIG. 11  is a flowchart showing an example of a vehicle control process. 
     
    
    
     DETAILED DESCRIPTION 
     In an active suspension system that utilizes an actuator and a spring, certain control operations contemplate compressing the spring using the actuator for an extended period of time. One example of such an operation arises when lowering the vehicle using the actuator for the purpose of passenger ingress or egress. Prolonged compression of the spring by the actuator may not be feasible due to power usage by the actuator and due to heat generation by the actuator. Disclosed herein are active suspension components that include locking structures that maintain compression of a spring while the actuator is no longer drawing power. 
       FIG. 1  is a block diagram that shows a vehicle  100  and functional subsystems thereof, including a suspension system  160 . The suspension system  160  is an active suspension system that is configured to control generally vertical motion of the wheels with a linear actuator that can apply upward and downward force to introduce energy into and absorb energy from the wheels. 
     The vehicle  100  generally includes a vehicle body  102  and a drive system  120  connected to the vehicle body  102 . The vehicle body  102  may, for example, include or define a passenger compartment for carrying passengers. The drive system  120  is configured to move the vehicle  100 , including the passenger compartment. The drive system  120  includes various functional subsystems, including a propulsion system  130  (i.e., for propelling the vehicle  100 ), a braking system  140  (i.e., for slowing the vehicle  100 ), a steering system  150  (i.e., for directing the vehicle  100  in different directions), a suspension system  160  (i.e., for supporting the vehicle  100 ), a sensing system  170  (i.e., for sensing various aspects of the vehicle  100 , including the various subsystems and the external environment), and a control system  180  (i.e., for controlling the various other subsystems individually or in a coordinated manner). The drive system  120  may be an autonomous drive system that operates the various functional subsystems to move the vehicle  100  to a user-selected location without further input from the user. 
     Referring to  FIG. 2 , the vehicle  100  includes wheels  104  (e.g., four) that are coupled to and support the vehicle body  102  (e.g., while travelling on a public roadway). The wheels  104  may be coupled to the vehicle body  102 , for example, with the propulsion system  130 , the steering system  150 , and the suspension system  160 . The wheels  104  may include tires, such that each wheel  104  may be considered a subassembly of a wheel rim and a tire. 
     The propulsion system  130  generally includes one or more motors  232 , one or more gearboxes  234 , and drive shafts  236  (e.g., half-shafts) operatively connecting each wheel  104  to one of the gearboxes  234 . Broadly speaking, the motors  232  provide torque to the gearboxes  234 , the gearboxes  234  alter the output torque (e.g., increase) and output speed (e.g., decrease) of the motors  232 , and the drive shafts  236  transfer torque from the gearboxes  234  to the wheels  104 . The motors  232  may provide positive torque for propelling the vehicle  100  in a forward direction and for decelerating the vehicle  100  when moving in a rearward direction, and may provide negative torque for propelling the vehicle  100  in a rearward direction and for deceleration the vehicle  100  when moving in a forward direction. The motors  232  may also function as generator, when receiving torque from the wheels  104 , and function to recharge a battery (not shown) or other energy storage system of the vehicle  100 . As shown, the propulsion system  130  may include a front propulsion system  131   a  and a rear propulsion system  131   b  that each include two motors  232  coupled to a gearbox  234  (e.g., a single gearbox) and associated with one drive shaft  236  and the one wheel  104  coupled thereto. Variations of the propulsion system  130  are contemplated, which may include a different number of driven wheels (e.g., only front or rear wheels being driven), a different number of the motors  232  associated with the wheels  104  (e.g., one motor associated with two wheels  104 ), and a different number of gearboxes  234  associated with the wheels  104  (e.g., one gearbox for each wheel  104 ). 
     The braking system  140  generally provides deceleration torque via friction for decelerating the vehicle  100  when moving in the forward direction and/or when moving in the rearward direction. 
     The steering system  150  generally includes one or more steering actuators  252  and steering linkages  254  operatively coupling each wheel  104  to one of the steering actuators  252 . Broadly speaking, the steering system  150  controls the pivoted position of the wheels  104  about generally vertical axes. The steering actuators  252  move the steering linkages  254  in inboard and outboard directions relative to the vehicle body  102  to, thereby, pivot the wheels  104  about the vertical axes. As shown, the steering system  150  may include a front steering system  151   a  and a rear steering system  151   b  that each include one steering actuator  252  that is associated with two steering linkages  254  and the wheels  104  coupled thereto. Variations of the steering system  150  are contemplated, which may include a different number of steering actuators  252  associated with the wheels  104  (e.g., one steering actuator for each wheel  104 ). 
     The suspension system  160  is an active suspension system in which the suspension components  262  transfer energy into and absorb energy from the wheels  104  with upward and downward movement relative to the vehicle body  102 . Broadly speaking, the suspension system  160  controls vertical motion of the wheels  104  relative to the vehicle body  102 , for example, to ensure contact between the wheels  104  and a surface of the roadway and to limit the influence of roadway conditions on undesirable movements of the vehicle body  102 . As shown, the suspension system  160  may include a front left suspension system  161   a , a front right suspension system  161   b , a rear left suspension system  161   c , and a rear right suspension system  161   d , each of which includes a suspension component  262  that is associated with one of the wheels  104 . Mechanical components of the suspension system  160 , including the suspension component  262  and other components discussed below, may be considered an assembly (e.g., a suspension assembly). Further details of the suspension system  160  are discussed in further detail below. 
     The sensing system  170  includes sensors for observing external conditions of the vehicle  100  (e.g., location of the roadway and other objects) and conditions of the vehicle  100  (e.g., acceleration and conditions of the various subsystems and their components). The sensing system  170  may include sensors of various types, including dedicated sensors and/or functional components of the various subsystems (e.g., actuators may incorporate sensors or portions of actuators may function as sensors such as by measuring current draw of an electric motor incorporated in an actuator). 
     The control system  180  includes communication systems and components (i.e., for receiving sensor signals and sending control signals) and processing components (i.e., for processing the sensor signals and determining control operations), such as a controller. The control system  180  may include various control subsystems, for example, associated with (or as part) of one or more of the various other subsystems described herein (e.g., the propulsion system  130 , the braking system  140 , etc.). 
       FIG. 3A  is a cross-sectional view of the suspension component  262  at a first length, and  FIG. 3B  is a cross-sectional view of the suspension component  262  at a second length. The second length is shorter than the first length owing to a greater degree of compression of portions of the suspension component  262 , as will be explained herein. 
     An upper end of the suspension component  262  is connected to the vehicle body  102  and a lower end of the suspension component  262  is connected to an unsprung component  306  that supports the wheel  104 . The unsprung component  306  moves upward and downward relative to the vehicle body  102  and may, for example, be a steering knuckle or a suspension control arm. The suspension component  262  defines a first load path between the vehicle body  102  and the unsprung component  306  through a passive suspension component, such as a spring. The suspension component  262  also defines a second load path between the vehicle body  102  and the unsprung component  306  through an active suspension component, such as a linear actuator, which in the illustrated example includes a screw actuator as will be described further herein. 
     The first and second load paths cooperatively function to transfer force axially between the unsprung component  306  and the vehicle body  102 . The first load carries a gravity preload of the vehicle  100  (i.e., load due to gravity irrespective of any dynamic loading) along with a portion of a dynamic load between the vehicle body  102  and the unsprung component  306 . The second load path carries another portion of the dynamic load between the vehicle body  102  and the unsprung component  306  and, as compared to the first load path, provides primary damping functions of the suspension system  160 . 
     The suspension component  262  includes a top mount  364 , a bottom mount  365 , an upper housing portion  366 , a lower housing portion  367 , a spring mount  368 , suspension spring such as a coil spring  369 , a screw actuator such as ball screw actuator  370 , and a locking structure  380 . The ball screw actuator  370  includes a shaft  371 , a ball nut  372 , a ball spline housing  373 , a rotor  374 , a stator  375 , a stator housing  376 , cooling passages  377 , and a cooling jacket  378 . The first load path includes at least the coil spring  369  or other type of suspension spring (e.g., air springs, torsion bars, etc.), and in the illustrated example also includes the top mount  364 , the bottom mount  365 , the upper housing portion  366 , and the spring mount  368 . The second load path includes at least the ball screw actuator  370  or other screw actuator (e.g., lead screw, roller screw, etc.), and in the illustrated example also includes the top mount  364 , the bottom mount  365 , and the upper housing portion  366 . Additional components may be included in the suspension component  262 , such as vibration isolators (e.g., dampers, bushings, etc.), position sensors, and load sensors. 
     The top mount  364  is coupled to an upper end of the upper housing portion  366  and the vehicle body  102  to transfer forces to the vehicle body  102 . The bottom mount  365  is separately coupled to lower ends of the coil spring  369  and the shaft  371  of the ball screw actuator  370  to transfer force to the unsprung component  306 . The spring mount  368  is connected to a lower end of the upper housing portion  366 , with the coil spring  369  being engaged and retained by the spring mount  368 , for example, by disposition of an upper end of the coil spring  369  in an annular channel defined by the spring mount  368 , such that the spring mount  368  extends between the spring mount  368  and the lower housing portion  367 . 
     The ball screw actuator  370  is disposed within the upper housing portion  366  and the lower housing portion  367 . The rotor  374  is a rotatable component in the form of a hollow, tubular structure that extends along a longitudinal axis of the upper housing portion  366 . The stator  375  is arranged around and radially outward from the rotor  374 . Using any suitable motor-generator configuration, the rotor  374  and the stator  375  are configured such that electromagnetic interaction of the rotor  374  and the stator  375  causes rotation of the rotor  374  when the stator  375  is energized (e.g., by selective energization of stator coils that are included in the stator  375 . 
     The stator  375  may be disposed in the stator housing  376 . In addition to providing structural support for the stator  375 , the stator housing  376  absorbs heat generated by the stator  375  when it is energized. Cooling passages  377  are defined on an outside periphery of the stator housing  376 . The suspension component  262  may be connected to a source of cooling media (e.g., liquid at a lower temperature than the stator housing  376 ) for circulating the cooling media through the cooling passages  377 . The cooling media is retained in the cooling passages  377  by the cooling jacket  378 , which is connected to the exterior of the stator housing  376 . 
     The ball nut  372  is a rotatable component of the ball screw actuator  370 . The ball nut  372  is connected to the rotor  374  and is rotated in unison with the rotor  374 . As the ball nut  372  is rotated by the rotor  374 , the ball nut  372  engages the shaft  371  through engagement of recirculating ball bearings that are disposed in the ball nut  372  with a helical groove that is formed on at least part of the shaft  371 , which causes the shaft  371  to translate axially relative to the upper housing portion  366  in response to rotation of the ball nut  372 . Thus, the shaft  371  is a translatable shaft, since it is able to translate linearly relative to portions of the suspension component  263 , including the upper housing portion  366 . 
     The ball spline housing  373  is also engaged with the shaft  371 , but functions as a linear bearing that resists rotation, to restrain the shaft  371  from rotating as a result of rotation of the ball nut  372  relative to the shaft  371 . The ball spline housing  373  includes recirculating balls that engage axial grooves (i.e., splines) that are formed on at least a portion of the shaft  371 . 
     The shaft  371  extends through an aperture that is defined by the lower housing portion  367 . A lower end of the shaft  371  is connected to the bottom mount  365  to allow the ball screw actuator  370  to apply force to the bottom mount  365 . 
     The locking structure  380  is configured to engage a portion of the ball screw actuator  370  to restrain motion of the ball screw actuator  370 . Restraining the motion of the ball screw actuator  370  fixes the translational position of the shaft  371  to maintain a current degree of compression of the coil spring  369  when supply of electrical power to the ball screw actuator  370  is discontinued. As one example, the locking structure  380  may be configured to restrain motion of the ball screw actuator  370  by engagement with a rotatable component, such as the rotor  374  or the ball nut  372  of the ball screw actuator  370 . By engagement with a rotatable component, the shaft  371  cannot back drive the ball screw actuator  370  because translation of the shaft  371  will be resisted by the ball nut  372  (which will not rotate when rotatable components of the ball screw actuator  370  are locked against rotation). As another example, the locking structure  380  may be configured to restrain motion of the ball screw actuator  370  by engagement with a translational component, such as the shaft  371 , such as by clamping the shaft  371 . In implementations where motion of a translational component is restrained, the ball screw actuator  370  may be replaced with a linear output actuator, such as a direct drive linear motor. Examples of restraining motion of rotational and translational components of the ball screw actuator  370  will be described further herein. 
       FIGS. 4A-4D  are schematic illustrations showing the locking structure  380  in a pre-engaged position ( FIG. 4A ), an engaged position ( FIG. 4B ), a disengaged position ( FIG. 4C ), and a released position ( FIG. 4D ) relative to a rotational component  474 . As an example, the rotational component  474  may be the rotor  374  of the ball screw actuator  370 . Alternatively, the rotational component could be the ball nut  372  of the ball screw actuator  370 . The locking structure  380  has a motor  481 , a lead screw  482 , a housing  483 , a pin having an inner pin part  484  and an outer pin part  485 , an end portion  486  of the outer pin part  485 , a first spring  487 , and a second spring  488 . The rotational component  474  has an outer surface  489  (i.e., a peripheral surface) and a recess  490  that is formed on the outer surface  489 . 
     The motor  481  is an electric motor operated by a signal (e.g., supply of electrical power) and is connected to the lead screw  482  for rotating the lead screw  482  in first and second rotational directions that correspond to advancing and retracting the pin. The motor  481  can be fixed to the housing  483 , which contains the inner pin part  484  the outer pin part  485 , the first spring  487 , and the second spring  488 . 
     The lead screw  482  is threaded to the inner pin part  484 , and the inner pin part  484  is disposed in an internal cavity of the outer pin part  485 . The first spring  487  is positioned in the internal cavity to urge the outer pin part  485  away from the inner pin part  484  and toward engagement with the rotational component  474 , which pre-loads the end portion  486  of the outer pin part  485  relative to the outer surface  489  of the rotational component  474  when the recess  490  is not aligned with the end portion  486  of the outer pin part  485 , as in the pre-engaged position of  FIG. 4A . 
     During rotation of the rotational component  474 , the recess  490  comes into alignment with the end portion  486  of the outer pin part  485 . Biased outward by the first spring  487  (and overcoming the force applied to the outer pin part  485  by the second spring  488 ), the end portion  486  moves outward into the recess  490  to define the engaged position of  FIG. 4B , in which rotation of the rotational component  474  is restrained by engagement of the end portion  486  of the outer pin part  485  with the recess  490  of the rotational component  474 . 
     To allow rotation of the rotational component  474 , the motor  481  is operated to retract the inner pin part  484  relative to the outer pin part  485 , which decompresses the first spring  487 . At this point, the end portion  486  of the outer pin part  485  remains in the recess  490  of the rotational component  474 , as shown in the disengaged position of  FIG. 4C . However, the force applied to the rotational component  474  by the end portion  486  of the outer pin part  485  is small relative to the forces applied in the pre-engaged position of  FIG. 4A  and the engaged position of  FIG. 4B , allowing rotation of the rotational component  474  to cause retraction of the end portion  486  of the outer pin part  485  from the recess  490 , such as by interaction of portions of the recess  490  (e.g., tapered surfaces) with the end portion  486  of the outer pin part  485 . Further retraction of the inner pin part  484  by rotation of the lead screw  482  causes the force applied by the first spring  487  to diminish until it is overcome by the force applied by the second spring  488 , to bias the end portion  486  of the outer pin part  485  away from the recess  490  of the rotational component  474 , as shown by the released position of  FIG. 4D . 
       FIGS. 5A-5B  are schematic illustrations showing a locking structure  580  in a disengaged position ( FIG. 5A ), and an engaged position ( FIG. 5B ) relative to a rotational component  574 . As an example, the rotational component  574  may be the rotor  374  of the ball screw actuator  370 . Alternatively, the rotational component may be the ball nut  372  of the ball screw actuator  370 . The locking structure  580  includes one or more pawl assemblies  581  that each have a pawl  582  that is pivotally movable into and out of engagement with the rotational component, a spring  583  that biases the pawl away from engagement with the rotational component  574 , a rotary actuator  584  (e.g., an electric motor), and a cam  585  that is eccentrically mounted relative to the rotary actuator  584  to drive the pawl  582  between engaged and disengaged position. In the disengaged position, as in  FIG. 5A , the pawl  582  is not engaged with the rotational component  574 . In the engaged position, as in  FIG. 5B , the pawl  582  is engaged with a feature that is formed on the rotational component  574 , such as a recess  590  that is formed on an outer surface  589  of the rotational component  574 , to restrain rotation of the rotational component  574 . 
       FIGS. 6A-6B  are schematic illustrations showing a locking structure  680  in a disengaged position ( FIG. 6A ), and an engaged position ( FIG. 6B ) relative to a rotational component  674 . As an example, the rotational component  674  may be the rotor  374  of the ball screw actuator  370 . Alternatively, the rotational component may be the ball nut  372  of the ball screw actuator  370 . The locking structure  680  includes a restraining collar  681  that is engageable with features  690  that are formed on an outer surface  689  of the rotational component  674 , and may extend radially outward from a nominal surface contour of the outer surface  689  of the rotational component  674 . Engagement of the restraining collar  681  with the features  690  is operable to restrain rotation of the rotational component  674 . 
     In the illustrated example the restraining collar  681  and the features  690  include sets of complementary engaging structures in the form of teeth that are configured to engage and disengage by axial movement of the restraining collar  681 . The restraining collar  681  is moved by one or more actuators, such as linear actuators  682  in the illustrated example, or other types of actuators such as rotary actuators, hydraulic actuators, or pneumatic actuators. The restraining collar  681  is fixed against rotation relative non-moving components of the suspension component  262 , such as the upper housing portion  366 . In the disengaged position, as in  FIG. 6A , the restraining collar  681  is not engaged with the rotational component  674 , and the rotational component  674  may rotate relative to the restraining collar  681 . In the engaged position, as in  FIG. 6B , the linear actuators  682  have translated the restraining collar  681  relative to the rotational component  674  and into engagement with the features  690  to restrain rotation of the rotational component  674 . 
       FIG. 7A  is a schematic illustration showing a locking structure  780  relative to a rotational component  774 , and  FIG. 7B  is a schematic illustration showing an axial end  792  of the rotational component  774 . As an example, the rotational component  774  may be the rotor  374  of the ball screw actuator  370 , in which case the axial end  792  is the upper axial end of the rotor  374 . Alternatively, the rotational component may be the ball nut  372  of the ball screw actuator  370 . 
     The locking structure  780  includes a frame  781  that is fixed to the suspension component  262 , such as to the upper housing portion  366 . The locking structure  780  includes a restraining plate  782  that is movable relative to the frame  781  toward and away from engagement with the rotational component  774  by actuators  783 . The restraining plate  782  is fixed against rotation relative to the frame  781 . The actuators  783  may be linear actuators or any or type of actuator that is able to cause motion of the restraining plate  782  relative to the rotational component  774 , such as by axial translation or by bending. The restraining plate  782  includes recesses  784 , such as depressions, channels, or apertures. The recesses  784  are arranged in a circular pattern complementary to the shape and size of the rotational component  774 . The rotational component  774  includes features  785  that are receivable in the recesses  784 . As best seen in  FIG. 7B , the features  785  are formed on the axial end  792  of the rotational component  774  and may be teeth, projections, tabs, or other structures that can be received in the recesses  784 . In a disengaged position, the restraining plate  782  is moved axially away from the rotational component  774  by the actuators  783 , such that the features  785  are not disposed in the recesses  784 , and the rotational component  774  is not restrained from rotating by the restraining plate  782 . In an engaged position, the restraining plate  782  is moved axially toward and into engagement with the rotational component  774  by the actuators  783 , such that the features  785  are disposed in the recesses  784 , and the rotational component  774  is restrained from rotating by the restraining plate  782 . 
       FIGS. 8A-8B  are schematic illustrations showing a locking structure  880  in a disengaged position ( FIG. 8A ), and an engaged position ( FIG. 8B ) relative to a translational component  871 . As an example, the translational component  871  may be the shaft  371  of the ball screw actuator  370 . The locking structure  880  includes a clamp defined by an inner collar  881  and an outer collar  882 . Actuators  883  are operable to move the outer collar  882  axially. The inner collar  881  has a split-collar structure, and the outer collar  882  engages the inner collar  881  at complementarily tapered surfaces. This configuration causes the inner collar  881  to contract and expand radially in response to axial movement of the outer collar  882  relative to the inner collar  881 . In the illustrated example, the inner collar  881  is relaxed in the disengaged position of  FIG. 8A . Downward motion of the outer collar  882  in response to movement of the actuators  883  causes the inner collar  881  to contract radially and clamp the translational component  871  in the engaged position of  FIG. 8B . Since portions of the locking structure  880  are fixed to the suspension component  262 , such as to the upper housing portion  366 , translation of the translational component  871  is restrained in the engaged position. 
       FIG. 9A  shows the vehicle  100  in a raised position, and  FIG. 9B  shows the vehicle  100  in a lowered position. The vehicle  100  is moved between the raised position and the lowered positions by the suspension components  262 . The suspension components  262  may be controlled, for example, by the control system  180 . Once the vehicle  100  is moved to the lowered position, the control system  180  engages the locking structures of the suspension components  262  to maintain the lowered position, and the control system  180  deenergizes the suspension components  262  to reduce energy consumption and to reduce heat production. The locking structures maintain the current degree of compression of the suspension components  262  (e.g., including compression of the coil spring  369  of each of the suspension components  262 ) when supply of electrical power to the suspension components  262  is discontinued. The locking structures are subsequently released by the control system  180  to allow the vehicle  100  to return to the raised position. 
       FIG. 10  is a schematic view of a controller  1000  that may be used to implement the control system  180  and/or other control systems of the vehicle  100 . The controller  1000  may include a processor  1001 , a memory  1002 , a storage device  1003 , one or more input devices  1004 , and one or more output devices  1005 . The controller  1000  may include a bus  1006  or a similar device to interconnect the components for communication. The processor  1001  is operable to execute computer program instructions and perform operations described by the computer program instructions. As an example, the processor  1001  may be a conventional device such as a central processing unit. The memory  1002  may be a volatile, high-speed, short-term information storage device such as a random-access memory module. The storage device  1003  may be a non-volatile information storage device such as a hard drive or a solid-state drive. The input devices  1004  may include any type of human-machine interface such as buttons, switches, a keyboard, a mouse, a touchscreen input device, a gestural input device, or an audio input device. The output devices  1005  may include any type of device operable to provide an indication to a user regarding an operating state, such as a display screen or an audio output, or any other functional output or control. 
       FIG. 11  is a flowchart showing an example of a vehicle control process  1100  that can be performed using the vehicle  100 , for example, by execution of computer interpretable program instructions by the control system  180 . 
     Initially the vehicle is in motion and is in a raised position (i.e., at a nominal ride height). In operation  1101 , a planned stop is detected, for example, based on information from an autonomous drive system. In operation  1102 , the vehicle  100  is moved from the raised position to the lowered position (i.e., the ride height is decreased) by shortening the suspension components  262  under control of the control system  180  in anticipation of the planned stop. In operation  1103 , the vehicle  100  is stopped. The lowered position is maintained while the vehicle  100  is stopped, for example, to allow passenger ingress and egress. In operation  1104 , motion of the vehicle  100  resumes, for example, under control by the autonomous drive system. In operation  1105 , the vehicle is moved from the lowered position to the raised position while the vehicle is in motion. 
     While the suspension components described herein include a coil spring (e.g., the coil spring  369 ), the systems and methods described herein can be implemented using other types of suspension springs, such as air springs. In suspension actuators in which the coil springs described previously are replaced with air springs that are pressurized by a compressor and valving system, some or all of the energy used to lower the vehicle could be pneumatic energy supplied by the air springs and/or the compressor. This would reduce the stall torque and thermal loads that are applied to the electromechanical actuator while lowering, holding, and engaging the lock. 
     In addition, in suspension actuators in which the coil springs described previously are replaced with air springs that include multiple air spring chambers, the air springs can be adjusted to a softest possible air spring stiffness while conducting the lowering and locking procedure. By switching to the largest air volume setting, the spring rate is lowered which significantly lowers the load on the electromechanical actuator during the lowering and locking operation. In some implementations, a very large soft setting air spring volume may be utilized for the lowering and locking procedure and/or for low speed driving use cases where the slow speed actuator excursions are large and therefore produce high losses and heating. 
     As used in the claims, phrases in the form of “at least one of A, B, or C” should be interpreted to encompass only A, or only B, or only C, or any combination of A, B and C.

Metadata:
Filing Date: 20180821
Publication Date: 20211116
Grant Date: 20211116
Priority Date: 20170907
Inventors: HALL, JONATHAN L.
LACKRITZ, NEAL M.
CARTER, TROY A.
Assignee: APPLE INC
CPC Classifications: [{"code": "B60G2204/47", "inventive": false, "first": false, "tree": "[]"}, {"code": "B60G2202/422", "inventive": false, "first": false, "tree": "[]"}, {"code": "B60G17/021", "inventive": true, "first": true, "tree": "[]"}, {"code": "B60G17/017", "inventive": true, "first": false, "tree": "[]"}, {"code": "B60G2500/30", "inventive": false, "first": false, "tree": "[]"}, {"code": "B60G17/017", "inventive": true, "first": false, "tree": "[]"}, {"code": "B60G2500/30", "inventive": false, "first": false, "tree": "[]"}, {"code": "B60G2204/47", "inventive": false, "first": false, "tree": "[]"}, {"code": "B60G17/0164", "inventive": true, "first": true, "tree": "[]"}, {"code": "B60G2204/47", "inventive": false, "first": false, "tree": "[]"}, {"code": "B60G2500/30", "inventive": false, "first": false, "tree": "[]"}, {"code": "B60G17/0164", "inventive": true, "first": true, "tree": "[]"}, {"code": "B60G17/017", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 78524057