Patent Publication Number: US-11035157-B2

Title: Closure latch for vehicle door having bidirectional power release function

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Patent Application No. 62/510,922 filed on May 25, 2017 and titled “Closure Latch for Vehicle Door Having Bidirectional Power Release Function”, the entire disclosure of which is hereby incorporated by reference. 
    
    
     FIELD 
     The present disclosure relates generally to closure latches for a vehicle passenger door. More particularly, the present disclosure is directed to a closure latch equipped with a bidirectional power release mechanism. 
     BACKGROUND 
     This section provides background information related to closure latches and is not necessarily prior art to the closure latch of the present disclosure. 
     Passive entry systems for vehicles are provided on some vehicles to permit a vehicle user who is in possession of the key fob to simply pull the door handle and open the door without the need to introduce a key into a keyhole in the door. The key fob is typically equipped with an electronic device that communicates with the vehicle&#39;s on-board control system to authenticate the user. When the user pulls the outside door handle to indicate that he/she wishes entry into the vehicle, an electric actuator associated with a door-mounted closure latch is actuated to release a latch mechanism so as to unlatch the door and permit subsequent movement of the door to its open position. The outside door handle may also be equipped with a switch that triggers the electric actuator. The latch mechanism may also be mechanically released from inside the vehicle since the inside door handle is connected to an inside release mechanism associated with the closure latch. In some jurisdictions, however, there are regulations that govern the degree of connection provided by the inside release mechanism between the inside door handle and the latch mechanism (particularly for a rear door, where children may be the occupants). 
     Many modern closure latches provide various power-operated features including power release and power lock functionality. Following completion of a power release operation, the power release mechanism within the closure latch must be “reset” to return the associated components from a released state to a home state. This reset function is required to prepare the closure latch for a subsequent closing and relatching of the door. 
     Typically, the power release mechanism includes a power release cam that is driven by a power release motor in a first or “releasing” direction from a home position into a released position for causing actuation of a latch release mechanism for releasing the latch mechanism. Thereafter, the power release motor drives the power release cam in a second or “resetting” direction for returning the power release cam to its home position. Reversing operation of the power release motor is known to generate noise during the resetting operation which is considered to be undesirable. Another issue with “powered” resetting of the power release mechanism is the potential inability to subsequently release the latch mechanism in the event of a power loss from the primary power source (i.e. the vehicle battery) and the closure latch&#39;s backup power source (i.e. the supercapacitors). This potential situation is particularly problematic in closure latches not equipped with a mechanical inside latch release mechanism since the vehicle occupant may be unable to release the latch mechanism and escape from the vehicle. 
     In view of the above, a recognized need exists to address current shortcomings associated with power release closure latches and provide solutions that advance the art and still meet all safety and regulatory requirements, such as a power release mechanism configured to provide a non-powered reset function under normal operating conditions and a powered reset function under emergency operating conditions. 
     SUMMARY 
     This section provides a general summary of the disclosure and is not intended to be considered as a comprehensive and exhaustive listing of its full scope or all of its aspects, features and objectives. 
     It is an aspect of the present disclosure to provide a closure latch for a vehicle having a latch mechanism, a latch release mechanism, and a power release mechanism for controlling powered actuation of the latch release mechanism to provide a power releasing function. The power release mechanism is also configured to provide a non-powered reset function under normal operating conditions and a powered reset function under emergency operating conditions. 
     It is a related aspect of the present disclosure to configure the power release mechanism to include a power release motor, a power release gear driven by the power release motor, and a return spring biasing the power release gear to a neutral/home position. Rotation of the power release gear in a first or “normal releasing” direction from the neutral/home position to a first released position causes a power release cam to actuate the latch release mechanism. Thereafter, the return spring drives the power release gear from its first released position back to its neutral/home position without powering (i.e. via mechanical backdriving) the power release motor so as to provide the non-powered reset function. Rotation of the power release gear in a second or “emergency releasing” direction from the neutral/home position to a second released position causes an emergency release cam to actuate the latch release mechanism. The return spring is not configured to mechanically return the power release gear from its second released position back to its neutral/home position such that the power release gear remains in its second released position. As such, the reset function is subsequently provided manually (manual reset) or by actuating the power release motor to drive the power release gear from its second released position to its neutral/home position. The power release motor is operable to drive the power release gear in the first releasing direction when a control unit indicates that power is supplied to the closure latch from the primary power source, thereby defining a “normal” release mode of operation. In contrast, the power release motor is operable to drive the power release gear in the second releasing direction when the control unit indicates that no power is available from the primary power source, thereby defining an “emergency” release mode of operation. 
     It is another related aspect of the present disclosure that the power release mechanism includes a bidirectional power release functionality. 
     In accordance with these and other aspects, the present disclosure is directed to a closure latch for a vehicle door. The closure latch comprises: a latch mechanism including a ratchet and a pawl, the ratchet being moveable between a striker capture position and a striker release position, the pawl being moveable between a ratchet holding position whereat the pawl holds the ratchet in its striker capture position and a ratchet releasing position whereat the pawl permits the ratchet to move to its striker release position; and a power release mechanism having an actuator release lever operatively connected to the pawl and a power release actuator, the actuator release lever being moveable between a non-actuated position whereat the pawl is maintained in its ratchet holding position and an actuated position whereat the actuator release lever moves the pawl to its ratchet releasing position, the power release actuator including a power release gear having a power release cam and an emergency release cam, a power release motor operable in a first mode to rotate the power release gear in a first releasing direction from a neutral/home position to a first released position for causing the power release cam to move the actuator release lever from its non-actuated position to its actuated position and is operable in a second mode to rotate the power release gear in a second releasing direction from its neutral/home position to a second released position for causing the emergency release cam to move the actuator release lever from its non-actuated position to its actuated position, and a return spring for driving the power release gear from its first released position back to its neutral/home position to define a mechanical, non-powered reset function. 
     Further areas of applicability will become apparent from the description provided herein. The description and specific embodiments listed in this summary are for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The drawings described herein have been provided to illustrate selected embodiments and specific features thereof and are not intended to limit the scope of the present disclosure. The present disclosure will now be described by way of example only with reference to the attached drawings, in which: 
         FIG. 1  is a perspective view of a motor vehicle with a passenger door that is equipped with a closure latch embodying the teaching of the present disclosure; 
         FIG. 2  is an isometric view of a closure latch equipped with a latch mechanism and a power release mechanism; 
         FIG. 3  is an isometric view showing the components of the power release mechanism associated with the closure latch shown in  FIG. 2 ; 
         FIG. 4  is a plan view of the components associated with an alternative configuration of a bidirectional power release mechanism associated with the closure latch of the present disclosure; 
         FIG. 5  is an isometric view of various components associated with the power release mechanism shown in  FIG. 4 ; 
         FIG. 6A  illustrates a power release gear associated with the power release mechanism shown in  FIGS. 4 and 5  located in a neutral/home position, and  FIG. 6B  illustrates the power release gear rotated in a first or “normal” releasing direction from the neutral/home position to a first released position when the closure latch is operating in a normal mode; 
         FIG. 7A  illustrates the power release gear located in its neutral/home position and  FIG. 7B  illustrates rotation of the power release gear in a second or “emergency” releasing direction from the neutral/home position to a second released position when the closure latch is operating in an emergency mode; 
         FIG. 8  is a sketch of another version of a bidirectional power release mechanism of the present disclosure with the power release gear shown in its neutral/home position; 
         FIG. 9  is similar to  FIG. 8  except that the power release gear is shown rotated from its neutral/home position to its first released position for providing a spring-loaded resetting function; and 
         FIG. 10  shows the power release gear rotated from its neutral/home position to its second released position. 
     
    
    
     DETAILED DESCRIPTION 
     An example embodiment of a closure latch for use in motor vehicle door closure systems is provided so that this disclosure will be thorough, and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms and that neither should be construed to limit the scope of the disclosure. In some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail. 
     Referring initially to  FIG. 1 , a closure latch  10  for a passenger door  12  of a motor vehicle  14  is shown positioned along a rear edge portion  16  of door  12  and is configured to releaseably engage a striker  18  secured in a door opening  20  formed in the vehicle&#39;s body  22  in response to movement of door  12  from an open position (shown) to a closed position. Door  12  includes an external or outside door handle  24  and an internal or inside door handle  26 , both of which are operatively coupled (i.e. electrically and/or mechanically) to closure latch  10 . 
     Referring now to  FIG. 2 , a non-limiting embodiment of closure latch assembly  10  is shown to generally include a latch mechanism, a latch release mechanism, a power release mechanism, and a power lock mechanism. The latch mechanism includes a ratchet  30  and a pawl  32 . Ratchet  30  is moveable between a first or “striker capture” position whereat the ratchet  30  retains the striker  18  and a second or “striker release” position whereat the ratchet  30  permits release of the striker  18 . A ratchet biasing member, such as a torsion spring  34 , biases ratchet  30  toward its striker release position. The pawl  32  is pivotably moveable relative to ratchet  30  between a first or “ratchet holding” position whereat the pawl  32  holds the ratchet  30  in its striker capture and a second or “ratchet releasing” position whereat the pawl  32  permits the ratchet  30  to move to its striker release position. A pawl biasing member, such as a coil spring  36 , biases pawl  32  toward its ratchet holding position. 
     The latch release mechanism includes, among other things, a pawl release lever  40  operatively connected to pawl  32  and which is movable between a first or “pawl release” position whereat the pawl release lever  40  causes the pawl  32  to move from the ratchet holding position to the ratchet releasing position and a second or “home” position whereat pawl release lever  40  permits pawl  32  to be maintained in the ratchet holding position. A pawl release lever biasing member, such as a suitable pawl release lever spring  42 , is provided to bias pawl release lever  40  to its home position. Pawl release lever  40  may be moved from its home position to its pawl release position by several components such as, for example, the power release mechanism. 
     The power release mechanism includes, among other things, a power release electric motor  46  having a rotatable motor output shaft  48 , a power release worm gear  50  secured for rotation with the motor output shaft  48 , a power release gear  52 , and a power release cam  54 . Power release cam  54  is connected for common rotation with power release gear  52  and is rotatable between a first or “pawl release” range of positions and a second or “pawl non-release” range of positions. Power release gear  52  is driven by worm gear  50  in response to actuation of power release motor  46  and, in turn, drives power release cam  54  which controls the pivoting movement of pawl release lever  40  between its home and pawl release positions. 
     The power release mechanism may be used as part of a passive entry feature. When a person approaches vehicle  14  with an electronic key fob and opens outside door handle  24 , an electronic latch release system associated with vehicle  14  senses both the presence of the key fob and that outside door handle  24  has been actuated (e.g. via communication between a switch  28  and an electronic control unit (ECU) shown at  60  that at least partially controls the operation of closure latch  10 ). In turn, ECU  60  actuates the power release mechanism to release the latch mechanism and unlatch closure latch  10  so as to open the vehicle door. 
     The power lock mechanism controls the operative connection between an inside release lever  62  associated with the inside door release mechanism and pawl release lever  40 . The power lock mechanism includes, among other things, a power lock actuator  64  and a lock mechanism  66 . 
     Referring now to  FIG. 3 , the components associated with a non-limiting embodiment of a power release mechanism  100  adapted for use with closure latch  10  are shown to include a power release actuator having a power release motor  101  with a motor shaft  102  driving a worm gear  104 , and a power release gear  106  having a release cam  108  formed thereon. Power release gear  106  is rotatable about a post  110  in a first or “releasing” (i.e. counterclockwise) direction and a second or “resetting” (i.e. clockwise) direction via actuation of power release motor  101 . Power release gear  106  is rotatable about post  110  between a “home” position (shown) and a “released” position for causing pivotal movement of an actuator release lever  112  from a first or “non-actuated” position (shown) into a second or “actuated” position. Actuator release lever  112  is supported for pivotal movement relative to a pivot post  114  and is normally biased toward its non-actuated position by an actuator lever spring  116 . Actuator lever  112  is operable in its non-actuated position to disengage its first leg segment  118  from pawl release lever  40 , when located in its home position, so as to permit pawl  32  to remain in its ratchet holding position. In contrast, movement of actuator lever  112  to its actuated position causes its first leg segment  118  to forcibly engage and pivot pawl release lever  40  from its home position to its pawl release position, thereby causing pawl  32  to move from its ratchet holding position to its ratchet releasing position. A second leg segment  120  of actuator release lever  112  is engageable with release cam  108  due to the biasing of actuator lever spring  116 . As such, rotation of power release gear  106  in its releasing direction from its home position to its released position causes corresponding pivotal movement of actuator release lever  112  from its non-actuated position into its actuated position. Likewise, rotation of power release gear  106  in its resetting direction from its released position to its home position results in corresponding pivotal movement of actuator release lever  112  from its actuated position to its non-actuated position. 
     Referring now to  FIG. 4 , a power release mechanism  200  is shown which is generally a modified version of power release mechanism  100  ( FIG. 3 ) and includes many similar components identified hereinafter and in the drawings using common reference numerals. Power release mechanism  200  is configured to provide a bi-directional releasing function, with each directional releasing operation associated with a distinct operating mode for closure latch  10 . As seen, power release mechanism  200  includes power release motor  101  with its motor shaft  102  driving worm gear  104 , a power release gear  202  having a power release cam  204  and an emergency release cam  206 , and a return spring  208  acting between power release gear  202  and a latch housing  210 . Power release gear  202  has gear teeth  212  meshed with worm gear  104  such that rotation of motor output shaft  102  in a first direction causing corresponding rotation of power release gear  202  in a first (i.e. clockwise) direction and rotation of motor output shaft  102  in a second direction causes corresponding rotation of power release gear  202  in a second (i.e. counterclockwise) direction. 
     Power release gear  202  is shown in  FIGS. 4, 5, 6A and 7A  located in a neutral/home position with actuator release lever  112  located in its non-actuated position such that pawl release lever  40  is located in its home position with pawl  32  located in its ratchet holding position, thereby maintaining ratchet  30  in its striker capture position for establishing the latched mode of closure latch  10 . In its neutral/home position, power release gear  202  is positioned such that neither of power release cam  204  and emergency release cam  206  are acting on actuation leg segment  120  of actuator release lever  112 . 
     When control unit  60  indicates that closure latch  10  is supplied with electrical power from the vehicle&#39;s primary power source (i.e. the battery), power release mechanism  200  is considered to be operating in a “normal release” mode. As such, when a signal is provided to release closure latch  10 , power release motor  101  is energized to rotate power release gear  202  in a first releasing direction (i.e. clockwise), as indicated by arrow “A”, from its neutral/home position ( FIG. 6A ) to a first released position ( FIG. 6B ). Such rotation of power release gear  202  causes power release cam  204  to engage actuator leg segment  120  of actuator release lever  112  and forcibly pivot actuator release lever  112 , in opposition to the biasing of spring  116 , from its non-actuated position to its actuated position for causing pawl  32  to move to its ratchet releasing position, thereby releasing ratchet  30  for movement to its striker release position. However, such rotation of power release gear  202  causes return spring  208  to be compressed (i.e. loaded) since its first end segment  214  is secured to power release gear  202  and its second end segment  216  engages a stationary portion of housing  210 . Upon release of the latch mechanism, a non-powered resetting function is completed. Specifically, power release motor  101  is turned off and return spring  208  backdrives power release gear  202  from its first released position ( FIG. 6B ) to its neutral/home position ( FIG. 6A ) which, in turn, backdrives motor shaft  102  and electric motor  101 . Since power release gear  202  is mechanically reset during operation of closure latch  10  in its normal operating mode, no noise is generated as is typically associated with powered resetting of the power release mechanism. 
     When control unit  60  indicates that closure latch  10  is not supplied with electrical power from the vehicle&#39;s primary power source and may be relying on a backup power source (i.e. supercapacitors), power release mechanism  200  is considered to be operating in an “emergency release” mode. As such, when a signal is provided to release closure latch  10 , power release motor  101  is energized to rotate power release gear  202  in a second releasing direction (i.e. counterclockwise), as indicated by arrow “B”, from its neutral/home position ( FIG. 7A ) to a second released position ( FIG. 7B ). Such rotation of power release gear  202  causes emergency release cam  206  to engage actuation leg segment  120  and forcibly pivot actuator release lever  112 , in opposition to the biasing of spring  116 , from its non-actuated position into its actuated position for causing pawl  32  to move to its ratchet releasing position, thereby releasing ratchet  30  for movement to its striker release position. However, such rotation of power release gear  202  in the second releasing direction does not act to cause return spring  208  to be loaded since its second end segment  216  is no longer engaged with a stationary component of latch housing  210 . Thus, power release gear  202  is held in its second released position. Subsequent resetting of power release mechanism  200 , required for moving power release gear  202  from its second released position back to its neutral/home position, is completed either manually (if no power) or electrically (via backup power) by driving power release motor  101  in the opposite direction. 
     Referring now to  FIGS. 8-10 , a modified version of power release mechanism  200  is shown as power release mechanism  200 ′ and is generally identical thereto with the exception that power release gear  202 ′ has a common cam  203  defining both a power release cam segment  204 ′ and an emergency release cam segment  206 ′. In other words, a single integral common cam is provided that defines both the power release cam and the emergency release cam. Otherwise, the functionality and operation of power release mechanism  200 ′ is substantially similar to that of power release mechanism  200 . 
     The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.