The present disclosure relates generally to closure latch assemblies for use with a closure panel in a motor vehicle closure system. More particularly, the present disclosure is directed to a closure latch assembly equipped with a latch mechanism, a latch release mechanism, and a power release actuator having a dual-stage geartrain and a mechanical back-up reset mechanism.
This section provides background information related to closure latch assemblies of the type used in motor vehicle closure systems and which is not necessarily prior art to the inventive concepts associated with the teachings of the present disclosure.
In an effort to meet consumer demand for motor vehicles equipped with closures systems providing advanced comfort and convenience features, many modern vehicles now include a passive keyless entry (PKE) system operable to permit locking and release of closure panels (i.e., side doors, sliding doors, liftgates, tailgates and decklids) without the use of a traditional manually-operated key-type entry system. Some of the most popular features now available with such vehicle closure systems include power locking/unlocking, power release and power cinching. Many of these “powered” features are provided by a closure latch assembly mounted to the moveable closure panel and which is typically equipped with a latch mechanism and one or more motor power-operated mechanisms interacting with the latch mechanism. These power-operated mechanisms may include, for example, a power latch release mechanism operable for selectively releasing the latch mechanism, a power lock mechanism operable for selectively locking the latch mechanism, and a power cinch mechanism operable for cinching the latch mechanism.
In many closure latch assemblies, the latch mechanism includes a ratchet and pawl arrangement configured to hold (i.e. “latch”) the closure panel in a closed position by virtue of the ratchet being held in a striker capture position to retain a striker mounted to a structural body portion of the vehicle. The pawl is operable in a ratchet holding position to engage and mechanically hold the ratchet in one of two distinct striker capture positions, namely, a secondary or “soft close” striker capture position and a primary or “hard close” striker capture position. When the ratchet is held in its secondary striker capture position, the latch mechanism functions to latch the closure panel in a partially-closed position relative to the body portion of the vehicle. Likewise, when the ratchet is held in its primary striker capture position, the latch mechanism functions to latch the closure panel in a fully-closed position relative to the body portion of the vehicle. The latch mechanism is defined to be operating in a latched state when the ratchet is held in one of its striker capture positions.
To subsequently release (i.e. “unlatch”) the closure panel for movement from either of its closed positions to an open position, the pawl is moved via actuation of the latch release mechanism from its ratchet holding position to a ratchet releasing position whereat the pawl is disengaged from the ratchet. Such shifting of the latch release mechanism form a non-actuated state into an actuated state functions to shift the latch mechanism from its latched state into an unlatched state. Upon disengagement of the pawl from the ratchet, a ratchet biasing arrangement functions to forcefully drive the ratchet from its striker capture position into a striker release position, thereby releasing the striker and allowing movement of the closure panel toward its open position.
In closure latch assemblies providing the power lock feature, a power lock actuator interacts with a lock mechanism for shifting the latch mechanism between locked and unlocked states. In closure latch assemblies providing the power cinch feature, a power cinch actuator interacts with a cinch mechanism for moving the ratchet from its secondary striker capture position into its primary striker capture position, thereby moving (i.e. “cinching”) the closure panel from its partially-closed position to its fully-closed position. Likewise, in closure latch assembling providing the power release feature, a power release actuator interacts with the latch release mechanism for moving the pawl from its ratchet holding position into its ratchet releasing position so as to shift the latch mechanism from its latched state into its unlatched state. Typically, each of the above-noted power actuators includes an electric motor controlled by an electronic latch controller unit (i.e. Latch ECU) associated with the closure latch assembly.
In closure latch assemblies providing the power release feature, the latch release mechanism is normally maintained in its non-actuated state and is only shifted into its actuated state when sensors indicate a door release operation has been requested and authenticated by the PKE system (i.e. via actuation of a key fob or a handle-mounted switch). Actuation of the power release actuator is required for shifting the latch release mechanism from its non-actuated state into its actuated state. Following completion of the power release operation, when the sensors detect that the ratchet is located in its striker release position, the latch release mechanism must be “reset,” that is, returned to its non-actuated state to permit subsequent latching of the latch mechanism upon movement of the closure panel from its open position into one of its closed positions. Resetting of the latch release mechanism is normally accomplished via the power release actuator. However, some closure latch assemblies are equipped with a manually-operated mechanical “backup” reset mechanism that can be actuated in response to a loss of electrical power (i.e. no battery power and the superconductor (SC) backup energy is depleted) for manually resetting the latch release mechanism into its non-actuated state.
To prevent precipitation and road debris from entering the vehicle, all closure panels are equipped with a resilient weather seal around its peripheral edge and which is configured to seal against a mating surface of the vehicle body. The weather seal also functions to reduce the transmission of road and wind noise into the passenger compartment. Since the weather seal is made from an elastomeric material, it compresses upon closing of the closure panel and is maintained in this compressed state via the closure latch assembly holding the closure panel in its fully-closed position. As is well recognized, increasing the compressive clamping force applied to the weather seal results in improved noise reduction with the interior passenger compartment. However, holding the weather seal in a highly compressed condition tends to bias the closure panel toward its open position such that this “opening” seal force is resisted by the pawl in its ratchet holding position and the ratchet in its primary striker capture position. Because the seal loads exerted on the latch mechanism are increased, the “release” force required to actuate the latch release mechanism for moving the pawl out of latched engagement with the ratchet and into its ratchet releasing position is also increased, thereby impacting the size and power requirements of the power release actuator. In addition, an audible sound, commonly referred to as “popoff” noise, is sometimes generated following actuation of the latch release mechanism and subsequent release of the latch mechanism due to the physical engagement between the striker and the ratchet caused by release of the compressive seal loads as the ratchet is driven from its primary striker capture position toward its striker release position.
To address the compromise between the desire for higher seal loads and lower latch release forces, it is known to provide the closure latch assembly with an arrangement configured to coordinate the release of the seal loads with powered release of the latch mechanism. In this regard, some closure latch assemblies are equipped with an alternative latch mechanism such as, for example, a dual pawl/ratchet type of latch mechanism configured to use the mechanical advantage of the additional pawl/ratchet arrangement to reduce the required latch release force. As another alternative, European Publication No. EP1176273 disclosed a power-operated latch release mechanism configured to provide a progressive release of the ratchet associated with the latch mechanism in an effort to reduce the popoff noise. As a further alternative, European Publication No. EP 0978609 discloses an eccentric latch release mechanism used in association with the latch mechanism to reduce the seal loads prior to release of the ratchet. It is also known to equip the closure latch assembly with a secondary or “safety” latch mechanism which only interacts with the latch mechanism in the event of a crash situation in order to prevent unintended release of the latch mechanism. Obviously, the inclusion of such additional mechanisms into the closure latch assembly, while providing a desirable feature, significantly impacts the complexity and packaging requirements.
Most closure latch assemblies providing power release functionality are equipped with a power actuator having an electric motor and a geartrain configured to actuate the latch release mechanism. In addition to operation during normal power release conditions, the power release actuator must also be capable of actuating the latch release mechanism via discharge of the Supercapacitor (9V) during increased “post-crash” seal load conditions (i.e. 1.5 KN-5.0 KN). Unfortunately, with some traditional single pawl/ratchet latch mechanisms, the power release actuator cannot generate the required mechanical advantage to fulfill the increased SC power release requirements at the higher portion of the crash seal load range. In these specific vehicular applications, the latch mechanism typically employed is the dual pawl/ratchet configuration providing reduced release force requirements with a concomitant increase in release time. Obviously, closure latch assemblies equipped with such dual pawl/ratchet types of latch mechanisms are more complex and expensive compared to a conventional single-type latch mechanism.
While current closure latch assemblies of the type used in motor vehicle closure systems are sufficient to meet customer and regulatory requirements, a recognized need exists to design and develop alternative power release actuators for use with single pawl/ratchet latch mechanisms that advance the technology and further address and overcome at least some of the known shortcomings.
This section provides a general summary of various inventive concepts associated with the teachings of the present disclosure. However, this section is not intended to be considered an exhaustive and comprehensive listing of all aspects, features, objectives, and possible embodiments associated with present disclosure.
In one aspect, a latch is provided, including: a multi-stage geartrain, wherein the multi-stage geartrain operatively couples an output of a motor of a power release actuator to a pawl of a latch release mechanism; wherein an output of multi-stage geartrain is decoupled from the pawl until after the multi-stage gear mechanism has developed inertia in response to actuation of the motor; wherein the pawl has a ratchet holding position whereat the pawl holds a ratchet in a latched state and a ratchet releasing position whereat the ratchet is an unlatched state; wherein, after developing inertia in response to actuation of the motor, the output of the multi-stage geartrain contacts the pawl and pivots the pawl from the ratchet holding position to the ratchet releasing position.
In one aspect, the multi-stage geartrain includes a first gear in meshed engagement with a second gear, wherein the first gear is a compound gear and the second gear is a sector gear.
In one aspect, the compound gear includes a worm wheel in meshed engagement with a worm gear, wherein the worm gear is disposed on an output shaft of the motor.
In one aspect, the sector gear includes an arm extending radially outward therefrom.
In one aspect, the arm is disposed in the same plane as the geartrain such that the arm is disposed within an axial height defined by the geartrain.
In one aspect, the arm has a curvature configured to act as a cam.
In one aspect, the arm includes a first curved surface that contacts the pawl and pivots a position of the pawl in response to a first range of rotational movement of the sector gear, and the arm includes a second curved surface that contacts the pawl and maintains the position of the pawl in response to a second range of rotational movement of sector gear that is beyond the first range.
In one aspect, the pawl includes a first leg segment extending in a first direction from a pivot axis of the pawl and a second leg segment extending in a second direction opposite the first direction from the pivot axis of the pawl, wherein the first leg segment is longer than the second leg segment.
In one aspect, the second leg segment includes a latch shoulder configured to contact the ratchet to hold the ratchet when the pawl is in the ratchet holding position, and the first leg segment includes a cam surface, wherein the arm extending from the sector gear contacts the cam surface to pivot the pawl away from the ratchet holding position.
In one aspect, the arm includes a first cam region and a second cam region, wherein the first cam region extends within a first radius of sector gear, wherein the second cam region extends between the first radius and a second radius that is greater than the first radius.
In one aspect, the second radius is greater than the maximum radius of the sector gear such that the arm extends beyond the radius of the sector gear.
In one aspect, the latch includes a printed circuit board (“PCB”), wherein PCB includes a plurality of hall sensors configured to detect the position of the sector gear, pawl, and/or the ratchet.
In one aspect, torque of the output of the geartrain increases following initial contact between the arm and the pawl and during further rotation of the sector gear.
In one aspect, the latch includes a manual release mechanism including a manual release lever having a manual release arm, wherein the pawl includes a boss disposed at an end of the pawl, wherein the manual release arm is spaced away from the boss and defines a gap when in a rest position, and wherein the manual release arm rotates toward the boss in response to manual actuation, wherein the manual release arm contacts the boss to pivot the pawl away from the ratchet holding position after the manual release arm rotates through the gap, wherein the manual release lever is coaxial with the sector gear and rotatable independently relative to the sector gear.
In one aspect, the latch includes a mechanical backup reset mechanism configured to permit manual movement of the sector gear from an end of travel position back to its home position for backdriving the geartrain and manually resetting the power release actuator into its non-actuated state.
In one aspect, the first gear and the second gear are mounted to an actuator housing that is separate from a latch plate, wherein the pawl and ratchet are mounted to the latch plate.
In another aspect, a method of controlling operation of a closure latch assembly is provided. The method includes the steps of: providing a closure latch assembly having a multi-stage geartrain, a power release actuator, a pawl, and a ratchet, wherein an output of the multi-stage geartrain is decoupled from the pawl in a rest position prior to actuation of the power release actuator, wherein the pawl has a ratchet holding position wherein the pawl holds the ratchet in a latched state and a ratchet releasing position wherein the pawl allows the ratchet to pivot to an unlatched state; actuating the power release actuator; pivoting the output of the geartrain through a degree of rotation prior to contacting the pawl and developing inertia; after developing inertia, contacting the pawl with the output of the multi-stage geartrain; after contacting the pawl, continuing to pivot the output of the geartrain and pivoting the pawl out of the ratchet holding position and into the ratchet releasing position.
In one aspect, the geartrain includes a first gear in the form of a compound gear in meshed engagement with a second gear in the form of a sector gear, wherein the sector gear includes an arm extending radially therefrom, wherein the arm is the output of the geartrain and contacts the pawl to pivot the pawl in response to contact therebetween.
In one aspect, a contact point defined between the arm and the pawl increases in a radially outward direction in response to continued rotation of the arm and pivoting of the pawl, wherein the contact point between the arm and the pawl at an end of travel position of the sector gear has a radius greater than a maximum radius of the sector gear.
In one aspect, the geartrain defines an axial height and the arm is disposed axially within the height of the geartrain.
It is an aspect of the present disclosure to provide a closure latch assembly for use with a motor vehicle closure panel system and which is equipped with a power-operated latch release mechanism operable for selectively shifting a single pawl/ratchet latch mechanism from a latched state into an unlatched state to provide power release functionality.
It is a related aspect of the present disclosure to configure the power-operated latch release mechanism of the closure latch assembly to include a power release actuator operable to generate increased latch release forces that are capable of shifting the single pawl/ratchet latch mechanism from its latched state into its unlatched state during high load conditions.
It is another related aspect of the present disclosure to configure the power release actuator to generate the increased latch release loads required to shift the single pawl/ratchet latch mechanism into its unlatched state in response to actuation of the power release actuator via a backup power supply to overcome high seal load conditions associated with a post-crash event.
It is another related aspect of the present disclosure to configure the power release actuator to include an electric motor and a dual-stage geartrain driven by the electric motor and which provides an increased output torque multiplication for generating the increased latch release forces while shifting the single pawl/ratchet latch mechanism from its latched state into its unlatched state within acceptable latch release time requirements.
It is a further related aspect of the present disclosure to configure the dual-stage geartrain to establish a first stage torque transmission ratio between a motor-driven worm gear and a first transfer gear associated with a compound gear and to establish a second stage torque transmission ratio between a second transfer gear associated with the compound gear and a power release gear that is adapted to directly or indirectly exert the latch release force on the single pawl/ratchet latch mechanism.
It is yet another related aspect of the present disclosure to provide the power release gear with a power release cam adapted to selectively engage a pawl release cam on the pawl of the single pawl/ratchet latch mechanism for moving the pawl from a ratchet holding position whereat the pawl holds the ratchet in a striker capture position to a ratchet releasing position whereat the pawl is disengaged from the ratchet to permit the ratchet to move from its striker capture position to a striker release position in response to the power release gear being rotated by the electric motor and the dual-stage geartrain from a home position to a pawl released position.
In accordance with another aspect of the present disclosure, the closure latch assembly further includes a manually-operated latch release mechanism operable for selectively shifting the single pawl/ratchet latch mechanism from its latched state into its unlatched state independently of actuation of the power-operated latch release latch mechanism.
In a related aspect, the manually-operated latch release mechanism includes a backup release lever interconnected via a cable actuation assembly to a door handle and having a manual release cam adapted to selectively engage a pawl release boss on the pawl of the single pawl/ratchet latch mechanism for selectively moving the pawl from its ratchet holding position into its ratchet releasing position in response to actuation of the door handle.
In accordance with a further related aspect of the present disclosure, the power release gear of the power-operated latch release mechanism and the backup release lever of the manually-operated latch release mechanism are coaxially aligned for independent movement about a common axis. In addition, the power release cam associated with the power-operated latch release mechanism and the manual release cam associated with the manually-operated latch release mechanism are arranged in a stacked configuration so as to selectively engage with a corresponding one of the pawl release cam and the pawl release boss formed on the pawl of the single pawl/ratchet latch mechanism.
In accordance with yet another aspect of the present disclosure, the closure latch assembly further includes a mechanical backup reset mechanism for permitting the power actuator to be manually reset from an actuated state following completion of the power release operation into a non-actuated state.
In accordance with another aspect of the present disclosure, methods are provided for actuation of the power-operated latch release during the power release operation, for manually resetting of the power release actuator via the backup reset mechanism, and for actuating the manually-operated latch release mechanism.
These and other aspects of the disclosure are provided by a closure latch assembly for a vehicle closure panel, comprising: a latch mechanism having a ratchet moveable between a striker capture position and a striker release position, a pawl moveable between a ratchet holding position whereat the pawl engages and holds the ratchet in its striker capture to define a latched state and a ratchet releasing position whereat the pawl is disengaged form the ratchet for permitting movement of the ratchet to its striker release position to define an unlatched state, a ratchet biasing member for biasing the ratchet toward its striker release position, and a pawl biasing member for biasing the pawl toward its ratchet holding position; a power-operated latch release mechanism operable in a non-actuated state to maintain the pawl in its ratchet holding position and in an actuated state to move the pawl from its ratchet holding position to its ratchet releasing position, the power-operated latch release mechanism including an electric motor and a dual-stage geartrain configured to generate a latch release force that is adapted to be exerted on the pawl for shifting the latch mechanism into its unlatched state, the dual stage geartrain including a worm gear driven by the electric motor, a power release gear adapted to exert the latch release force on the pawl, and a compound gear having a first transfer gear meshed with the worm gear to establish a first stage torque transmission ratio and a second transfer gear meshed with the power release gear to establish a second stage torque transmission ratio; and a latch controller for controlling actuation of the electric motor when a power release signal is detected and authenticated.
Further areas of applicability will become apparent from the following detailed description when considered in conjunction with the accompanying drawings. As noted, the general descriptions and specific examples set forth in this summary are intended only to identify certain inventive concepts and features associated with the present disclosure and are not to be interpreted to unduly limit the fair and reasonable scope of the present disclosure.
These and other aspects, features, objectives, and advantages of the present disclosure will be readily appreciated, as the same become better understood, by reference to the following detailed description when considered in connection with the accompanying drawings wherein:
Example embodiments of a closure latch assembly constructed according to the teachings of the present disclosure will now be described more fully with reference to the accompanying drawings. To this end, the example embodiments are provided so that this disclosure will be thorough, and will fully convey its intended scope to those who are skilled in the art. Accordingly, 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. However, 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 present disclosure. In some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail.
The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms “a,” “an,” and “the” may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises,” “comprising,” “including,” and “having,” are inclusive and therefore specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed.
When an element or layer is referred to as being “on,” “engaged to,” “connected to,” or “coupled to” another element or layer, it may be directly on, engaged, connected or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly engaged to,” “directly connected to,” or “directly coupled to” another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.
Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as “first,” “second,” and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be terms a second element, component, region, layer or section without departing from the teachings of the example embodiments.
Spatially relative terms, such as “inner,” “outer,” “beneath,” “below,” “lower,” “above,” “upper,” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. Spatially relative terms may be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the FIGS. is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the example term “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotate 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.
In the following detailed description, the expression “closure latch assembly” will be used to generally indicate any power-operated latch device adapted for use with a vehicle closure panel to provide a power latch release function. Additionally, the expression “closure panel” will be used to indicate any element moveable between an open position and at least one closed position, respectively opening and closing an access to an inner compartment of a motor vehicle and therefore includes, without limitations, decklids, tailgates, liftgates, bonnet lids, and sunroofs in addition to the sliding and pivoting passenger doors of a motor vehicle to which the following description will make explicit reference, purely by way of example.
Referring initially to
Referring now primarily to
Pawl 58 is configured to include a first elongated leg segment 78 and a second leg segment 72 which are located on opposite sides of pawl pivot post 60. Second leg segment 72 defines a latch shoulder 74. Pawl 58 is moveable about pawl pivot post 60 between a ratchet releasing position (
With continued reference to the drawings, latch release mechanism 46 is shown, in this non-limiting embodiment, to generally include a power release cam 80 and a pawl release lug 82. Likewise, power release actuator 48 is shown, in this non-limiting embodiment, to generally include an electric motor 86 and a dual-stage geartrain 88. Latch release mechanism 46 and power release actuator 48 are mounted within an actuator housing 90 (best shown in
Pawl release lug 82 extends axially an end of pawl 58, which can be seen in
With reference again to
Dual-stage geartrain 88 provides a variety of advantages. Cam 80 extends radially outward from sector gear 104 in the same plane as the geartrain 88. In one aspect, cam 80 is in the same plane as the sector gear 104. In one aspect, the cam 80 is disposed in the axial space defined by the compound gear 100. In one aspect, the cam 80 axially overlaps both the compound gear 100 and the sector gear 104. In each of these aspects, cam 80 is not disposed above sector gear 104 and does not add axial height to the geartrain 88 defined by the compound gear 100 and the sector gear 104. Accordingly, the axial height of the components is reduced, thereby reducing packaging size. Additionally, the use of a sector gear 104 with a radially extending arm for the cam 80 reduces the weight of components.
Moreover, with the arm extending form the sector gear 104, the arm of the cam 80 can extend to greater radius or have a greater radial length than the gear 104 itself, allowing for torque to increase at contact points corresponding to points greater than the radius of the gear. Put another way, the radius or sector portion of the gear 104 may be reduced relative to the arm 80 without sacrificing the amount of available torque that can be applied by the arm 80 on the pawl 58.
Drive gear 108 is configured, in the non-limiting embodiments, as a worm gear, driven by motor 86 and directly engaged with outermost teeth of compound gear 100. Compound gear 100 is configured, in the non-limiting embodiments, to include a first large-diameter transfer gear 112 and a second small-diameter transfer gear 114 which are interconnected for common rotation about a rotary axis defined by first gear post 102. In one aspect, gears 112 and 114 are fixed relative to each other. First transfer gear 112 is configured, in the non-limiting embodiments, to define a helicoidal gear (or worm wheel) with helical gear teeth meshed with threads of worm gear 108. Second transfer gear 114 is configured as a spur gear having spur gear teeth. Power release gear 104 (also known as sector gear 104) is also configured as a spur gear having its spur gear teeth in constant mesh with the spur gear teeth on second transfer gear 114 of compound gear 100, and is supported for rotation about the rotary axis defined by second gear post 106.
In one aspect, gear posts 102 and 106 are fixed to actuator housing 90, such that compound gear 100 and power release gear 104 are attached to actuator housing 90 rather than latch plate 42. Such attachment is illustrated in
In accordance with the teachings of the present disclosure, dual-stage geartrain 88 works, in cooperation with electric motor 86, to generate an increased latch release output force of a magnitude required to provide powered release of latch mechanism 44 (via latch release mechanism 46) during high seal load conditions such as, for example, occurring as part of a post-crash situation. In addition to generating the increased latch release force levels, power release actuator 48 is capable of meeting latch release time values in compliance with customer and regulatory requirements. To provide these advantages, the geared interaction between worm gear 108 and first transfer gear 112 of compound gear 100 establishes a first speed ratio and torque multiplication factor while the geared interaction between second transfer gear 114 of compound gear 100 and power release gear 104 establishes a second speed ratio and torque multiplication factor which, when combined, provide a dual-stage speed/torque transmission ratio between motor shaft 110 and power release gear 104. As is clearly shown, power release cam 80 is fixed to, or integrally formed with, power release gear 104 while pawl release lug 82 is fixed to, or integrally formed with, an end portion of first leg segment 78 of pawl 58. Illustratively and in accordance with one possible configuration, the power release cam 80 extends from the power release gear 104 within the same plane as the power release gear 104 and within the missing portion of a gear wheel partly defining the sector gear configuration of the power release gear 104. This rotation of power release gear 104 in a first or “releasing” direction (i.e. clockwise in
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As shown diagrammatically in
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Note that latch release mechanism 46 is still shown operating in its non-actuated state while latch mechanism 44 is likewise still shown operating in its latched state. However, it will be appreciated that the non-actuated state of
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As such, latch shoulder 74 is held displaced from engagement with an arcuate external guide surface 71 of ratchet 52 while ratchet 52 is located in its striker release position. This extra rotation of pawl 58 from its ratchet releasing position (
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With further reference to
The latch assembly 18 illustrated herein provides various advantages in the opening of the ratchet 52. Pawl 58 includes first leg segment 78 and second leg segment 72. First leg segment 78 is longer than second leg segment 72. First leg segment 78 is also longer than the lever arm defined by cam 80 that extends radially from the sector gear 104. The long arm defined by first leg segment 78 extends between the pivot point of pawl 58 and the cam surface of lug 82. This arm is substantially longer than the short arm defined between the pivot point of pawl 58 and the contact point with the ratchet 52 when the pawl 58 is in the ratchet holding position.
The pawl 58 provides the greatest resistance to opening when the pawl 58 is engaged with the ratchet 52 in the ratchet holding position. Initial contact by the cam 80 occurs as a relatively short radius along the cam 80. As the cam 80 continues to rotate, the lever arm of the cam 80 increases while acting on the long arm of the first leg segment 78 of the pawl 58. As the contact point on the cam 80 moves outward during release, the lever arm increases, and continues to act on the generally long arm of the first leg segment 78.
Thus, the initial contact of the cam 80 is closer to the pivot point of the sector gear 104, where more torque is initially needed to overcome static forces and seal loads. The contact point moves radially outward during release as less torque is needed and static loads have been initially overcome. Upon additional movement, less force is necessary, as the spring bias is the primary force to overcome because seal loads have been overcome.
Power release actuator 48 can be reset from its actuated state back into its non-actuated state upon internal latch sensors detecting at least one of power release gear 104 being located in its end of travel position, power release cam 80 being located in its full travel position and pawl 58 being located in its ratchet disengaging position. Resetting power release actuator 48 allows ratchet 52 to later become latched and held in its latched positon. Prior to reset, a closing force on the ratchet would be overcome by the ratchet bias due to the pawl 58 being held in its ratchet releasing of fully actuated position (out of engagement with the ratchet).
With reference to
In one aspect, first hall magnet 706 may be disposed at one end of the sector gear 104. In one aspect, first hall magnet 706 may be disposed on the sector gear 104 such that the magnet 706 is adjacent hall sensor 702 (above, shown in
Similarly, second hall magnet 708 may be disposed on an end of pawl 58, and is aligned with hall sensor 704 when pawl 58 is in its rest position, shown in
Additional third and fourth hall sensors 710 and 712 and third hall magnet 714 may be provided for the ratchet 52 to detect the positon of the ratchet 52. For example, hall sensors 710 and 712 (
A fourth hall sensor 716 may be disposed in a position corresponding to the position of the hall magnet 708 of the pawl 58 when the pawl 58 is in the ratchet releasing position.
Referring back to
Referring now to
In addition, particular attention to
IS latch release mechanism 200 is shown, in this non-limiting embodiment, to generally include a backup release lever 202 supported for rotary movement relative to latch plate 42 (and housing 90) via second gear post 106, a backup release lever spring 204, a manual release cam 206, a pawl release boss 208, and a cable actuation assembly 210. Backup release lever 202 is moveable about second gear post 106 between a first or “home” position (
Manual release cam 206 is shown to be fixed to, or integrally formed on, backup release lever 202 and defines a contoured drive surface 206A. Likewise, pawl release boss 208 is shown fixed to, or integrally formed on, first leg segment 78 of pawl 58 and defines a pawl cam surface 208A.
As such, a “stacked” compact arrangement is provided for the components associated with facilitating both the power release and the manual release of latch mechanism 44. Since manual release cam 206 is moveable in concert with backup release lever 202, rotation of backup release lever 202 about pivot post 106 between its home position and its end of travel position results in corresponding movement of manual release cam 206 between a first or “rest” position (
Cable actuation assembly 210 is shown to include a tubular guide sheath 220 and a cable 222 disposed with guide sheath 220. A first end of cable 222 has a ferrule 224 that is retained within a retention aperture 228 formed in backup release lever 202.
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With reference to
With reference to
The inventive concepts associated with the exemplary embodiments of the present disclosure shown in the drawings and disclosed in the above description are generally directed to addressing and overcoming shortcomings of conventional closure latch assemblies equipped with a single pawl/ratchet latch mechanism and a power-operated latch release mechanism which are incapable of generating sufficient mechanical advantage and corresponding latch release forces required to facilitate latch release in post-crash high seal load conditions (i.e. up to about 5 kN) via a backup energy source (i.e. 9V Supercapacitor). However, most single pawl/ratchet latch mechanism configurations are well-suited for facilitating latch release in lower post-crash seal load conditions (i.e. up to about 1.5 kN) and have shown, both experimentally and mathematically, to generate actual latch release times (i.e. in the range of about 50 ms) that are significantly better than typical customer/regulatory requirements (i.e. in the range of about 150 ms). The solution presented by the present disclosure is to compromise between slightly increased latch release times (still well within the acceptable range) and significantly increased mechanical advantage providing correspondingly increased latch release forces. This solution is provided by integrating a dual-stage geartrain into the power release actuator that is operably disposed between the electric motor and the latch release mechanism in a compact arrangement. In particular, the dual-stage geartrain is designed to increase the overall system mechanical transmission ratio while staying well within the acceptable latch release time requirement. Moreover, this solution is scalable and the transmission ratio generated by the dual-stage geartrain and the power output of the electric motor can be adjusted according to specific post-crash seal load requirements. For solutions up to about 2-3 kN post-crash seal load requirements, the two-start motor worm 108 embodiment shown in association with
With reference to
In contrast, the one-start motor worm 108 embodiment associated with
In
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 scope of protection afforded to the disclosure. Individual elements or features of a particular mechanism or embodiment are not intended to be limited to that particular mechanism or embodiment but, where applicable, are interchangeable and can be used in alternative embodiments, even if not specifically shown or described. The same may be varied in many ways and such variations are not to be regarded as a departure from the disclosure, but rather contemplated to be included with the fair and reasonable scope of the disclosure.
Number | Date | Country | |
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63033262 | Jun 2020 | US |