Patent Publication Number: US-2019195342-A1

Title: Transmission shifter assembly with secondary shifting

Description:
TECHNICAL FIELD 
     The present disclosure relates generally to a gear shift system for a vehicle transmission. 
     BACKGROUND 
     In some vehicles, a gear shift lever in a passenger compartment of the vehicle can be moved by an operator of the vehicle to shift the vehicle transmission between its park gear and other gears, such as reverse, neutral and forward drive gears. The shift lever is mechanically coupled to the transmission through a cable that transmits the shift lever movement to a transmission shift mechanism. Other vehicles use a so-called “shift-by-wire” system wherein an operator shift lever or shift control unit is not physically coupled to the transmission shift mechanism by a cable. Instead, the shift control unit is electrically coupled to a shift actuator that is arranged to shift the transmission upon receipt of a signal from the shift control unit that a transmission gear shift is desired by the operator. It may be desirable, in at least some circumstances, to selectively prevent movement of the shift lever to prevent shifting the transmission at least until certain conditions are satisfied. For example, to shift the transmission out of park, a vehicle brake may need to be depressed or some other driver action may be needed. In some instances, it may be desirable to shift the transmission without a user command to do so. 
     SUMMARY 
     At least some implementations of a transmission gear shifter include a first shift member having a body rotatable about an axis among multiple positions, a retainer movable relative to the body, an actuator coupled to the retainer and a second shift member coupled to the first shift member. The retainer is movable between a first position in which the retainer prevents movement of the body and a second position in which the retainer permits movement of the body. The actuator drives the retainer between the first position and second position. And the second shift member is driven by the actuator between first and second positions to rotate the body. In at least some implementations, the second shift member is engaged by the retainer and driven by movement of the retainer. 
     In at least some implementations, the retainer and body include control features that are radially overlapped relative to the axis when the retainer is in the first position are not radially overlapped when the retainer is in the second position. The control features may include include axially extending stop surfaces of the retainer and the body. The retainer may include one or more control features with one of the one or more retainer control features selectively and releasably engageable with a first control feature of the body when the body is in a first position, and the body may also include a second control feature that is selectively and releasably engageable by one of the one or more retainer control features when the body is in a second position that is different than the first position of the body. 
     In at least some implementations, the second shift member has a first end, a second end and is coupled to a pivot between the first end and second end for rotation of the second shift member about the pivot, and the second shift member may be coupled to the body between the pivot and first end and the retainer is engageable with the second shift member between the pivot and second end, and wherein rotation of the body causes the second shift member to rotate about the pivot and engagement of the retainer with the second shift member during movement of the retainer causes the second shift member to rotate about the pivot and rotate the body. The distance from the pivot to the first end may be greater than the distance from the pivot to the second end, and the body may rotate about an axis that is parallel to an axis of the pivot. Further, the second shift member may rotate about the axis of the pivot and in at least one position of the body, the second shift member may intersect an imaginary line that intersects the axis about which the body rotates and the axis of the pivot. 
     In at least some implementations, the second shift member includes a slot and the body includes a drive member received within the slot, and during rotation of the body, the drive member moves relative to the second shift member within the slot. The drive member may be closely received within the slot to prevent lost motion between the body and the second shift member. In at least some implementations, the retainer includes a cam surface at least a portion of which is located between the pivot and second end, and the cam surface is inclined relative to the path of movement of the retainer so that engagement of the retainer with the cam surface of the second shift member causes increased rotation of the body. 
     In at least some implementations, a shifter for a vehicle transmission includes a first shift member having a body rotatable about an axis between a park position, a reverse position, a neutral position and a drive position, and the first shift member has at least one shifter control feature. A retainer is movable along a linear path relative to the body and has at least one retainer control feature, the retainer is movable between a first position in which the retainer control feature overlaps the shifter control feature when the shifter is in the park position to prevent rotation of the body, and a second position in which the retainer control feature does not overlap the shifter control feature and rotation of the body is permitted. An actuator is coupled to the retainer to drive the retainer between the first position and second position. And a second shift member is coupled to the first shift member so that the second shift member is in a first position when the first shift member is in the park position and the second shift member is in a position different than the first position when the first shift member is not in the park position, and the second shift member has a portion engageable by the retainer as the retainer moves from the second position to the first position so that when the retainer is in the first position the second shift member is in the first position and the first shift member is in the park position. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The following detailed description of some implementations of a shifter will be set forth with regard to the accompanying drawings, in which: 
         FIG. 1  is a perspective view of a shifter with a portion of a first shift member, shown as a rotatable selector, in section and only part of an outer housing shown; 
         FIG. 2  is a side view of the shifter of  FIG. 1 ; 
         FIG. 3  is a perspective view of certain components of the shifter; 
         FIG. 4  is a perspective view of the components shown in  FIG. 3  from a different angle; 
         FIG. 5  is a perspective view of a second body of the selector, a second shift member, a retainer, an actuator for the retainer and a portion of a lower housing or base; 
         FIG. 6  is a perspective view similar to  FIG. 5  but without the second body of the selector; 
         FIG. 7  is a perspective view of the components shown in  FIGS. 3 and 4 , illustrating the selector in a first position and the retainer in a first position blocking rotation of the selector out of its first position; 
         FIG. 8  is a bottom view showing the actuator, the retainer in section, the second shift member and the second body, all in the positions shown in  FIG. 7 ; 
         FIG. 9  is a view similar to  FIG. 7  but with the retainer in a second position; 
         FIG. 10  is a view similar to  FIG. 8  but with the retainer in the second position; 
         FIG. 11  is a view similar to  FIG. 10  but with the second body in a second position; 
         FIG. 12  is a view similar to  FIG. 11  but with the second body in a third position; 
         FIG. 13  is a view similar to  FIG. 9  but with the second body in the third position and the retainer in a third position blocking rotation of the second body out of the third position; 
         FIG. 14  is a view similar to  FIG. 12  but with the second body and retainer in the positions shown in  FIG. 13 ; 
         FIG. 15  is a view similar to  FIG. 14  but with the second body in a fourth position and the retainer in its second position permitting rotation of the second body relative to the retainer; and 
         FIG. 16  is a top view of the components in the positions shown in  FIG. 15 . 
     
    
    
     DETAILED DESCRIPTION 
     Referring in more detail to the drawings,  FIGS. 1-5  illustrate a rotary gear shifter  10  that may be used to shift among various gears of a transmission. In at least some implementations, the shifter  10  is not directly mechanically coupled to the transmission and instead communicates electrically with an actuator coupled to the transmission that, in turn, causes a change in the selected transmission gear in a so-called shift-by-wire system. The shifter  10  may include a first shift member, such as a dial, knob or other rotary selector  12 , that may be manually rotated by a user through multiple positions corresponding to multiple gears of the vehicle transmission. By way of non-limiting examples, the selector  12  may include and be rotated to one or more positions that correspond to park, reverse, neutral and drive gears for a vehicle transmission. 
     The selector  12  may be mounted to a housing  14  (only part of which is shown to better illustrate internal components) that is arranged to be mounted within a vehicle. The housing  14  may have an upper portion or cover  16  ( FIGS. 1 and 2 ) and a base  18  coupled to the cover to define an at least partial enclosure for the selector  12  and related shifter components, as set forth below. The selector  12  may be carried by the housing  14  for rotation relative to the housing about a central axis  20 . And so that the selector may be manually actuated by a user to cause a transmission gear change, the selector  12  may extend at least partially out of the cover  16 . In the example shown, the cover  16  includes a generally cylindrical column  22  about which the selector  12  rotates and a flange  24  from which the column  22  extends and which is coupled to the base  18 . 
     Within the enclosure, the shifter  10  may include a circuit board  26  on which one or more circuit elements, such as a microprocessor or controller  28 , may be mounted. In at least some implementations, the circuit board  26  is generally planar and is mounted perpendicularly to the axis  20  of rotation of the selector  12 . If desired, a gasket or other seals may be provided between the cover  16  and the circuit board  26 . For example, a gasket may be provided between the flange  24  of the cover  16  and the circuit board  26 . The gasket and/or other seals may help to isolate the circuit elements on the circuit board  26  from liquids and other contaminants, if desired. 
     The housing base  18 , or at least a portion thereof, is shown in  FIGS. 1-7  among others. The base  18  may include a post  30  ( FIGS. 5 and 6 ) about which part of the selector  12  is received and which may help guide the rotation of the selector  12 , and other features to mount or interact with various components within the housing  14 , as will be discussed below. In at least some implementations, the base  18  may include one or more feedback surfaces  32  ( FIG. 6 ) defined in one or more segments  34  that span a desired circumferential distance that may be sufficient to include the range of rotary motion of the selector  12 . Radially inner surfaces  32  of the segments  34  face inwardly toward the axis  20  and have circumferentially spaced apart peaks  36  and valleys  38  at different radial distances. 
     Spring-biased or flexible plungers  40  ( FIGS. 7-15 ) coupled to the selector  12  ride along the feedback surfaces  32  as the selector  12  is rotated to provide force feedback to a person rotating the selector. More specifically, the valleys may correspond to the various positions of the selector (P, R, N and D) and an increased force may be needed to pass the plungers  40  over a peak  36  between adjacent valleys  38 , and then the spring or other return force may tend to assist selector rotation toward a valley as the plunger  40  rides along an inclined portion of a feedback surface  32  between a peak and valley. The variation in force needed to rotate the selector  12  that is created by these force feedback surfaces  32  assist the user in finding a desired position, and also in retaining the selector  12  in a selected position as an increased force is needed to remove the plunger  40  from a valley  38  (doing so requires compression of the spring). While described with regard to a spring biasing a plunger  40 , the plunger  40  could instead be made from a flexible and resilient material that is compressed as the plunger nears and passes by a peak  36  and expands as the plunger nears and enters a valley  38 . 
     In the example shown, the base  18  includes two diametrically opposed segments  34  and the selector  12  includes two diametrically opposed plungers  40  to provided balanced forces on the selector. Of course, this is just one example and other arrangements may be used including, for example, axially facing feedback surfaces instead of the radially oriented surfaces shown, one plunger and one segment, or more than two sets of plungers and feedback surfaces. 
     The selector  12  may include a user actuated first body  42  that may include or be coupled to a decorative cover  44  that is fixed to the first body for co-rotation with the first body. The first body  42  may include a cavity  46  or open space in which one or more buttons, lights, wires or other devices and things may be mounted on or adjacent to the column. The buttons may permit some shifting of the transmission (e.g. manual upshifts and downshifts in a sport mode), selection of infotainment system functions (e.g. radio, navigation and the like), and/or selection of other vehicle functions (e.g. heating and cooling settings). The light or lights may provide illumination of certain features of the selector  12 , such as various indicia or features used to indicate the various positions of the selector. In the illustrated example, the letters P, R, N and D are provided on the selector cover  44  and may be illuminated when selected. 
     The cavity  46  of the first body  42  may be defined at least in part by a cylindrical sidewall  48  which may be open at its ends, if desired. The first body  42  may also include one or more legs  50  (see e.g.  FIGS. 2-4 ) that extend axially from the sidewall  48  and are coupled to a second body  52  for co-rotation of the first body  42  and second body  52 . This provides some space between the first and second bodies  42 ,  52  in which components may be received. Of course, the legs  50  and provided space between the first and second bodies  42 ,  52  are not necessary and any such components can be provided within the cavity  46  or not at all, as desired. 
     The second body  52  may be fixed to the legs  50  or some other portion of the first body  42  for co-rotation with the first body. The second body  52  may be mounted to the housing  14 , such as by the post  30  that extends into or through a central opening  54  ( FIGS. 3 and 5 ) in the second body  52  so that the second body (and connected first body) rotate relative to the post and housing. In the example shown, the second body  52  is disc-shaped, with an upper face  56  facing the first body  42 , a lower face  58  that faces in the opposite direction (e.g. toward the base  18  of the housing  14 ) and an axially and circumferentially extending sidewall  60  at the radial outer surface of the second body  52 . 
     Further, the circuit board  26  may extend between the first and second bodies  42 ,  52  of the selector  12 , with the legs  50  extending through holes in the circuit board, or located outboard (e.g. adjacent to side edges) of the circuit board. A portion of the upper housing  16 , such as the flange  24  and column  22 , may also extend between the first and second bodies  42 ,  52  of the selector  12  to facilitate rotary mounting of the selector. In addition to or instead of these things, the electronic controller  28 , which may include a microprocessor, could be received within the cavity  46 . The controller  28  may be used to manage the operation of the shifter  10  including any buttons, lights or other features provided with the shifter, if desired. With portions of the selector  12  on either side of the circuit board  26 , various electronic components may be located in close proximity to different portions of the selector to facilitate electrical coupling of the components to the circuit board  26  and controller  28 . 
     An actuator  62  may be provided to drive one or both of a retainer  64  and a second shift member  66 . As set forth in more detail below, the retainer  64  may selectively block rotation of the selector  12  and the second shift member  66  may be driven in certain circumstances to rotate the selector  12  and cause a transmission gear change without user actuation of the selector. In the example shown, the actuator  62  is carried by the housing base  18 , which may include a cavity  68  in which a portion of the actuator is received. A clip  69  may overlie the actuator to secure the actuator  62  to the base  18 , if desired. 
     In at least some implementations, the actuator  62  may be any desired form of rotary or linear actuator suitable to move the retainer  64  relative to the second body  52  as set forth below. In the example shown, the actuator is a reversible electric motor  62  with a rotary drive shaft  70 . The drive shaft  70  is coupled to a drive member  72  that is coupled to and drives the retainer  64 . In the example shown, the drive member is a cylindrical spindle  72  that has one or more outwardly extending threads  74  ( FIG. 6 ) that mate with internal thread(s) of the retainer  64  to linearly drive the retainer relative to the actuator  62  and the second body  52 . When the drive shaft  70  and spindle  72  are rotated in a first direction the retainer  64  is moved away from the motor  62 , and when the drive shaft  70  and spindle  72  are rotated in a second direction the retainer  64  is moved toward the motor  62 . The motor  62  may be controlled and actuated by the controller  28  on the circuit board  26  or by a different vehicle controller, as desired. 
     As shown in  FIGS. 1 and 2 , in at least some implementations, the housing  14  may include or carry a guide member or track  76  that extends at least part of the way between the actuator cavity  68  and the portion of the housing  14  including the post  30 . The retainer  64  may be slidably moved along a linear path defined by the track  76  and relative to the second body  52 . The track  76  may be defined by one or more linear surfaces of the base  18 , or by a component carried by the base. Accordingly, the rotary motion of the spindle  72  causes linear movement of the retainer  64 , and rotation of the retainer is prevented by engagement of the retainer with the track  76 . In this regard, the retainer  64  may include one or more depending flanges  78  arranged parallel to the track  76  and axially overlapped with the track (relative to the main axis  20 ) to guide movement of the retainer  64  along the track  76 . 
     To control rotation of the second body  52  and hence, the selector  12 , the retainer  64  may include one or more control features  80  ( FIG. 6 ) that interact with control features  82  ( FIG. 8 ) provided on the selector (e.g. the second body  52 ). The retainer control features  80  and selector control features  82  cooperate to inhibit or prevent rotation of the selector  12  in certain positions or the selector and/or in certain operating circumstances. For example, the retainer  64  may be positioned so that one or more of its control features  80  overlap one or more selector control surfaces  82  to prevent rotation of the second body  52  when the selector  12  is in the position corresponding to the transmission being in park. To shift the transmission out of park, a driver may have to take some action before rotating the selector  12 , such as applying a vehicle brake. Upon detection that the vehicle brake has been applied, the actuator  62  may be energized to drive the retainer  64  to a position in which the retainer control features  80  are not overlapped with the selector control features  82  so that the second body  52  may be rotated relative to the retainer  64 . 
     Similarly, in some instances, such as when a vehicle transmission has been in the neutral gear position for longer than a threshold time, it may be desirable to prevent shifting out of neutral without the driver taking some prerequisite action prior to rotating the selector  12 . This is a so-called neutral lock. Such driver action may be applying the brake or pushing a button, for example. Upon detection that the transmission has been in neutral for longer than the threshold time, the actuator  62  may be commanded to move the retainer  64  to a position in which one or more of its control features  80  prevent rotation of the second body  52 . And upon detection of the prerequisite driver action to shift out of neutral, the actuator  62  may drive the retainer  64  to a position that permits the second body  52  to be rotated relative to the retainer  64  so that the selector  12  may be rotated to shift the transmission. 
     In at least some implementations, the retainer control features  80  and selector control features  82  include opposing surfaces that, when aligned, are axially and radially overlapped so that rotation of the selector  12  is prevented. The control features  80 ,  82  may include some combination of blocking members and voids, wherein a blocking member may be received at least partially in a void or space defined by control features when it is desired to prevent rotation of the selector. In the example shown, the retainer includes the blocking members and the second body includes the voids, as is described further below. But other arrangements may be used including providing the second member with one or more blocking members and the retainer with one or more voids, or some combination of these. 
     In the example shown, the retainer  64  has a first control feature or first blocking member shown as a first tab  84  that has oppositely facing surfaces that extend axially and radially (relative to the axis  20  of the second body  52 ). In the example shown, the retainer  64  also has a second control feature or second blocking member shown as a second tab  86  that also has oppositely facing surfaces that extend axially and radially. The second tab  86  is radially spaced from the first tab  84  and provides a second structure that may be used to selectively prevent rotation of the second body  52 . In the example shown, the first tab  84  is located radially inwardly of the second tab  86  (that is, the first tab is closer to the axis  20  than is the second tab). The first tab may be arranged radially within the periphery of the second body  52  in at least some positions of the retainer  64 , and the second tab  86  may be radially outboard of the second body  52  in at least some positions of the retainer  64 . A gap  88  ( FIGS. 5 and 6 ) may be provided between the tabs  84 ,  86  and the sidewall  60  of the second body  52  may be received in the gap  88  in some positions of the retainer  64 . Of course, other arrangements may be used, as desired, including only one tab or more than two tabs, as well as tabs in different locations and structures other than tabs. The tabs  84 ,  86  may be provided in the same piece of material as the portion of the retainer  64  engaged with the spindle  72  and the retainer may thus be defined in a single, unitary body, if desired. 
     As shown in  FIGS. 7-15 , in more detail, the second body  52  has a first control feature that includes at least one stop surface  89  ( FIGS. 8 and 10 ) that defines at least part of a first void  90  arranged to receive a tab  84 ,  86  of the retainer  64  so that the tab and stop surface are radially overlapped. Two stop surfaces  89  that define the first void  90  are shown as extending from the lower face  58  of the second body  52  and having a radial length and axial height. When the first tab  84  is radially aligned with the first void  90 , rotation of the second body  52  is prevented by engagement of the stop surfaces  89  with the retainer (e.g. a tab). 
     In at least some implementations, the second body  52  may include a second control feature that includes opposed stop surfaces  91  ( FIG. 10 ) circumferentially spaced apart to define a second void  92  between them. The second void  92  is shown as being open to the radial periphery of the second body  52  and has a radial length and axial height. The second tab  86  of the retainer  64  may be selectively received within the second void  92  such that rotation of the second body  52  is prevented by engagement of the second body  52  with the retainer (e.g. the second tab  86 ). 
     In at least some implementations, the second body  52  may include a third control feature. The third control feature may also include opposed stop surfaces  93  ( FIG. 10 ) circumferentially spaced apart to define a third void  94  between them. Like the first void  90 , the stop surfaces  93  of the third void  94  are shown as extending from the lower face  58  of the second body  52  and have a radial length and axial height. When the first tab  84  is received in the third void  94 , rotation of the second body  52  is prevented. In at least some implementations, the third void  94  is radially aligned with the second void  92  and the first and second tabs  84 ,  86  are received in the second and third voids  92 ,  94  at the same time. Of course, other arrangements may be provided and only one tab and one void may be needed to prevent selector rotation in any position. 
     Any desired number and arrangement of control features may be provided on the retainer  64  and second body  52  to provide desired control of the selector rotation. The control features could also be provided on the first body and the retainer  64  could interact with the first body as desired, or with another component that moves as the selector  12  is rotated. 
     The retainer  64  may further include a drive surface  96  arranged to engage, during at least a portion of the movement of the retainer, the second shift member  66  that is coupled to the selector  12 . When the drive surface  96  of the retainer  64  engages and displaces the second shift member  66 , the second shift member causes rotation of the selector  12  and a corresponding transmission gear shift. This may be desirable in a number of situations. For example, if a vehicle is turned off without first rotating the selector to shift the transmission to park, it may be desirable to automatically shift the vehicle into park via the second shift member  66 . The second shift member  66  could also or instead rotate the selector  12  to shift the transmission to neutral or some other position, as desired. 
     With reference to  FIG. 16 , in at least some implementations, the second shift member  66  is a rigid arm that is coupled to a pivot  98  between first and second ends  100 ,  102  for rotation about the pivot  98 , the axis of which may be parallel to the rotational axis  20  of the selector  12 . The second shift member  66  is coupled to the second body  52  between the pivot  98  and first end  100  and the retainer  64  is engageable with the second shift member  66  between the pivot  98  and second end  102 . Rotation of the second body  52  causes the second shift member  66  to rotate about the pivot  98 , and engagement of the retainer  64  with the second shift member  66  during movement of the retainer  64  causes the second shift member  66  to rotate about the pivot  98  which rotates the second body  52 , and hence, the entire selector  12 . 
     In the implementations shown, the second shift member  66  includes a slot  104  that extends between the pivot  98  and first end  100 , and the second body  52  includes a drive member, shown as a post  106  received within the slot  104 . During rotation of the second body  52 , the post  106  moves relative to the second shift member  66  within the slot  64 . The distance from the pivot  98  to an end  108  of the slot  104  closest to the first end  100  of the second shift member may be greater than the distance from the second end  102  to the pivot  98  to provide a mechanical advantage so that comparatively less movement of the retainer  64  (when engaged with the second shift member  66 ) causes more rotation of the second body  52 . Further, the post  106  may be located toward the radial periphery of the second body  52  to improve the leverage and force for rotation of the selector  12  by the second shift member  66 . In at least some implementations, the actuator  62 , through the retainer  64  and second shift member  66 , may move the selector  12  from any position back to the position corresponding to park. In other words, the second shift member  66  and retainer  64  are arranged to move the selector  12  through its full rotary range of motion. The post  106  may be somewhat closely received within the slot  104  to reduce or eliminate lost motion between the post  106  and second shift member  66 . That is, when the post  106  moves (due to rotation of the second body  52 ) the second shift member  66  moves, and vice versa. To maintain the second shift member  66  in contact with the post  106 , a torsion spring  110  ( FIG. 7 ) may rotatably bias the second shift member  66  about the pivot  98 . Further, the post  106  and second shift member  66  may move from one side of an imaginary line  112  ( FIG. 16 ) or plane extending between the pivot  98  and axis  20  to the other side during the range of rotation of the selector  12 . The post  106  is closest to the pivot  98  when aligned with the line  112  between the pivot  98  and axis  20 . 
     The shifter  10  may include one or more position sensors to provide a positive indication of the position of one or more components, such as the retainer  64  and the selector  12 . As shown in  FIG. 5  (among others), a first sensor element may be coupled to the retainer  64  and is shown as including a magnet  114  ( FIGS. 3, 5 and 6 ) received within a cavity of the retainer  64 . A first sensor  116  ( FIG. 2 ) may be carried by the circuit board  26 , for example, and may be a hall-effect or other type of sensor responsive to movement of the magnet  114  as the retainer  64  moves. Of course, sensor types other than magnetic may be used, as desired, including but not limited to optical and contact based resistive sensors (e.g. potentiometers). A second sensor element may be carried by the selector  12  for rotation about the axis  20  when the selector rotates, to facilitate a determination of the rotary position of the selector. In the example shown, the second sensor element includes a magnet  118  ( FIG. 5 ) that is fixed to the second body  52 . A second sensor  120  ( FIG. 2 ) may be carried by the circuit board  26 , for example, and may be a hall-effect or other type of sensor responsive to movement of the second magnet as the second body rotates. Of course, sensor types other than magnetic field sensors may be used, as desired, including but not limited to optical and contact based resistive sensors (e.g. potentiometers). The first and second sensors  116 ,  120  may be coupled to the controller  28  so that the positions of the retainer  64  and second body/selector  12  can be determined during operation of the shifter  10 . 
     The operation of the shifter  10  will now be described. In  FIGS. 7 and 8 , the shifter is shown in a park lock position. In this position, the selector  12  is in a first position that corresponds to the transmission being in park, and the retainer  64  is in a first position in which the retainer prevents rotation of the selector  12 . In more detail, in the position shown, the first tab  84  of the retainer  64  is received in the first void  90  of the second body  52 . So arranged, rotation of the selector  12  is prevented by engagement of the second body  52  with the first tab  84 . While the first void  90  is shown as including opposed stop surfaces  89 , rotation of the selector  12  in one direction may be blocked by engagement of the selector with a separate stop surface, for example, a stop surface defined by the housing or another component. In the example shown, the stop surface is provided by a cushion  122  ( FIGS. 6 and 7 ) that is mounted to the housing  14  to provide a less abrupt stop of the selector rotation. A similar cushion  124  ( FIG. 6 ) and stop surface may be provided at the opposite end of the rotation of the selector  12  and rotation of the selector  12  may be confined to occur between the opposed stop surfaces  122 ,  124 . Accordingly, the selector  12  may only be rotated in one direction out of the park position, and the first void  92  may be arranged to prevent rotation of the selector in that direction without need for a second stop surface  89 . 
     To permit rotation of the selector  12  out of the park position, the actuator  62  is commanded to move the retainer  64  away from the first position, to a second position in which the retainer does not prevent rotation of the selector. That is, the first tab  84  is moved out of and is radially spaced from the first void  90 , as is shown in  FIGS. 9 and 10 . In the views of  FIGS. 8, 10-12, 14 and 15 , to facilitate view of the tabs  84 ,  86 , only a portion of the retainer  64  is shown and the tabs appear to be floating. Movement of the retainer  64  to the second position may occur in response to the driver taking some prerequisite action, such as actuating a vehicle brake or otherwise. In this position, the selector  12  may be rotated out of the park gear without the retainer  64  interfering or blocking rotation of the second body  52 . 
       FIG. 11  illustrates the selector  12  in a second position, which corresponds to the transmission being in reverse gear. The retainer  64  is in its second position and neither tab  84 ,  86  of the retainer is overlapped with a void  90 ,  92 ,  94  of the second body  52 . Thus, the selector  12  may be rotated from the second position to a third position (corresponding to the transmission being in neutral) or back to the first position (corresponding to park). 
       FIG. 12  illustrates the selector  12  in the third position and the retainer  64  in the second position. In this arrangement, the vehicle transmission is in neutral and the selector  12  may be rotated from the third position back to the second position or into a fourth position (corresponding to the transmission being in a forward drive gear). If one or more criteria are met, the controller  28  will cause the actuator  62  to move the retainer  64  relative to the second body  52  so that the retainer  64  blocks rotation of the selector  12  out of the third position. In  FIGS. 13 and 14 , the retainer  64  is shown in a third position. In this position, the second tab  86  is received within the second void  92 , and the first tab  84  is received in the third void  94 . While both tabs  84 ,  86  are shown as blocking rotation of the second body  52 , only one may be needed. Further, this third position of the retainer puts the retainer  64  closest to the axis  20  and farthest from the actuator  62 , although other arrangements may be used. In this position of the shifter  10 , the selector  12  cannot be rotated to cause a transmission shift without the retainer  64  being moved to unblock rotation of the second body  52 . 
     When the controller  28  actuates the actuator  62 , the retainer  64  is moved from the third position to or toward the second position sufficiently such that the tabs  84 ,  86  are clear of the voids  92 ,  94 . After this retainer movement, the selector  12  can be rotated to the fourth position, as shown in  FIGS. 15 and 16 , or to the second position, as shown in  FIG. 11 . 
     As noted above, rotation of the selector  12  moves the second shift member  66  as can be seen by comparison in the various figures, especially  FIG. 5  which shows a first position of the second shift member  66  which is achieved when the selector  12  is in the first position and  FIG. 16  which shows a second position of the second shift member  66  which is achieved when the selector  12  is in the fourth position (or some position other than the first position of the selector). 
     In at least some implementations, when the selector  12  is in a position other than the first position, the selector  12  may be driven to the first position or back toward the first position by the actuator  62  acting on the second shift member  66  through the retainer  64 . In this position shown in  FIGS. 15 and 16 , the drive surface  96  of the retainer  64  is engaged with a cam surface  128  of the second shift member  66  near the pivot  98 . The cam surface  128  is, at least when the selector  12  is not in the first position, not parallel to the path of movement of the retainer drive surface  96 . Driving the retainer  64  back toward the actuator  62  causes the drive surface  96  to engage the cam surface  128  and rotate the second shift member  66  about the pivot  98 . Rotation of the second shift member  66  drives the second body  52  for rotation by engagement of the second shift member  66  with the post  106 . 
     In at least some implementations, the cam surface  128  is at its greatest angle relative to the path of motion of the drive surface  96  when the selector  12  is in the fourth or drive position, or whatever is the furthest position of the selector from the first or park position. The angle of the cam surface  128  relative to the path of motion of the retainer  64  and its drive surface  96  decreases as the second shift member  66  rotates in the direction that corresponds with the selector rotation back toward the first or park position. As the selector  12  rotates, the plungers  40  ride over the force feedback features  32 , so the actuator  62 , retainer  64  and second shift member  66  need to provide sufficient force to rotate the selector  12  through the various positions and associated force feedback features  32 . 
     In this way, the second body  52  and selector  12  may be rotated from the fourth position, through the third and second positions and to the first position. As the selector  12  reaches the first position, the cam surface  128  may be generally aligned with the path of motion of the drive surface  96  such that further rotation of the second body  52  does not occur. This permits the first tab  84  to be moved into the first void  90  without rotation of the second body  52  which would move the first void  90  out of alignment with the first tab  84 . In this way, the retainer  64  can be moved back to its first position, and then the shifter  10  is returned to the park position shown in  FIGS. 7 and 8 . 
     Of course, it may also be possible to move the shifter  10  to a different position other than the first position, such as the third position in which the transmission is in neutral. Instead, the shifter  10  could be driven/rotated in the opposite direction, e.g. from a lower numbered position to a higher numbered position by suitably arranged driving and cam surfaces (which may involve driving the retainer away from the actuator toward an extended position). 
     While the forms of the invention herein disclosed constitute presently preferred embodiments, many others are possible. It is not intended herein to mention all the possible equivalent forms or ramifications of the invention. It is understood that the terms used herein are merely descriptive, rather than limiting, and that various changes may be made without departing from the spirit or scope of the invention.