Patent Publication Number: US-2019186553-A1

Title: Systems and methods for a two-way clutch with a predetermined interference

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This application is based on, claims priority to, and incorporates herein by reference in its entirety U.S. Provisional Patent Application No. 62/607,570, filed on Dec. 19, 2017, and entitled “Systems and Methods for a Two-Way Clutch with a Predetermined Interference.” 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH 
     Not Applicable. 
     BACKGROUND 
     Conventional two-way clutches can include a driven member and a drive member that may bi-directionally displace along with, or relative to, the driven member. In some applications, a two-way clutch can selectively transition between modes where the driven member and the drive member move in unison, and where the drive member is allowed to move relative to the driven member. 
     BRIEF SUMMARY 
     The present disclosure relates generally to two-way clutches and, in particular, to two-way clutches with a predetermined interference applied to a locking mechanism. 
     In one aspect, the present disclosure provides a two-way clutch that includes a driven member, a drive member, and a locking mechanism operable to contact the driven member and the drive member, in response to an outside force applied to the drive member that loads the locking mechanism. The two-way clutch further includes an engaging member. When the locking mechanism is in an unloaded state, the engaging member contacts the locking mechanism to provide a predetermined interference that biases the locking mechanism out of engagement with at least one of the driven member and the drive member. 
     In one aspect, the present disclosure provides a two-way clutch that includes a driven member having a first mating surface, a drive member having a second mating surface, and a locking mechanism arranged between the first mating surface and the second mating surface. The locking mechanism is operable to contact the first mating surface and the second mating surface, in response to an outside force applied to the drive member that loads the locking mechanism. The two-way clutch further includes an engaging member. The engaging member provides a predetermined interference on the locking mechanism to hold the locking mechanism off of at least one of the first mating surface and the second mating surface, when the locking mechanism is in an unloaded state. 
     In another aspect, the present disclosure provides a cam phasing system configured to selectively vary a rotational relationship between a crankshaft and a camshaft of an internal combustion engine. The cam phasing system includes a driven component rotatably coupled to the crankshaft, a drive component rotatably coupled to the camshaft, and a locking mechanism operable to contact the driven component and the drive component, in response to a torque pulse applied to the camshaft that loads the locking mechanism. The cam phasing system further includes an engaging member. The engaging member provides a predetermined interference on the locking mechanism to hold the locking mechanism off of at least one of the driven component and the drive component, when the locking mechanism is in an unloaded state. 
     In another aspect, the present disclosure provides a method for reducing an input force required to actuate a cam phasing system. The mechanical cam phasing system is configured to selectively vary a rotational relationship between a crankshaft and a camshaft of an internal combustion engine and includes a driven member, a drive member, a locking mechanism, and an engaging member. The engaging member is configured to selectively displace the locking mechanism. The method includes rotatably coupling a driven member to the crankshaft, rotatably coupling a drive member to the camshaft, and providing predetermined interference on a locking mechanism, via the engaging member, such that a gap exists between the locking mechanism and at least one of the driven member and the drive member in an unloaded state, thereby reducing an input force required to act on the engaging member to displace the locking mechanism and actuate the cam phasing system. 
     The foregoing and other aspects and advantages of the disclosure will appear from the following description. In the description, reference is made to the accompanying drawings which form a part hereof, and in which there is shown by way of illustration a preferred configuration of the disclosure. Such configuration does not necessarily represent the full scope of the disclosure, however, and reference is made therefore to the claims and herein for interpreting the scope of the disclosure. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The invention will be better understood and features, aspects and advantages other than those set forth above will become apparent when consideration is given to the following detailed description thereof. Such detailed description makes reference to the following drawings. 
         FIG. 1  is a schematic illustration of a two-way clutch according to one aspect of the present disclosure. 
         FIG. 2A  is a schematic illustration of a two-way clutch with a predetermined interference applied to a locking mechanism and with the locking mechanism in an unloaded state according to one aspect of the present disclosure. 
         FIG. 2B  is a schematic illustration of the two-way clutch of  FIG. 2A  with an outside force applied in a first direction and a first locking member of the locking mechanism in a compressed state. 
         FIG. 2C  is a schematic illustration of the two-way clutch of  FIG. 2B  with the outside force in the first direction removed and the locking mechanism in an unloaded state. 
         FIG. 2D  is a schematic illustration of the two-way clutch of  FIG. 2A  with an outside force applied in a second direction and a second member of the locking mechanism in a compressed state. 
         FIG. 3A  is a schematic illustration of a conventional two-way clutch without a predetermined interference with a locking mechanism in an unloaded state. 
         FIG. 3B  is a schematic illustration of the conventional two-way clutch of  FIG. 3A  with an outside force applied in a first direction and a first locking member of the locking mechanism in a compressed state. 
         FIG. 3C  is a schematic illustration of the conventional two-way clutch of  FIG. 3B  with the outside force in the first direction removed and the locking mechanism in a compressed state. 
         FIG. 3D  is a schematic illustration of the conventional two-way clutch of  FIG. 3A  with an outside force applied in a second direction and a second locking member of the locking mechanism in a compressed state. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  illustrates a non-limiting example of a two-way clutch  100  according to the present disclosure. The two-way clutch  100  includes a driven member  102 , a drive member,  104 , a locking mechanism  106 , and an engaging member  108 . In some non-limiting examples, the driven member  102  may be coupled to a device that is configured to input energy thereto, such that the driven member  102  travels in unison with the device. For example, the driven member  102  may be coupled to a motor (e.g., an electric motor, an internal combustion engine, etc.) for rotation therewith. The drive member  104  may be coupled to another component that is also coupled to the device, which drives the driven member  102 , but may be allowed to displace with or relative to the driven member  102 . 
     Generally, the locking mechanism  106  may be arranged between the driven member  102  and the drive member  104 . The locking mechanism  106  may be configured to selectively allow relative motion between the driven member  102  and the drive member  104 . For example, the locking mechanism  106  may be movable between a locked position and an unlocked position. In the unlocked position, the locking mechanism  106  may allow the drive member  104  to displace a predetermined amount relative to the driven member  102  in a desired direction. In the locked state, the locking mechanism  106  may inhibit relative motion between the driven member  102  and the drive member  104 . 
     In some non-limiting examples, the engaging member  108  is in engagement with the locking mechanism  106  and may be movable independent of the driven member  102  and the drive member  104 . For example, the engaging member  108  may be selectively movable in response to an input force applied by an input mechanism (e.g., an actuator) coupled thereto. The engaging member  108  may be selectively displaced (e.g., via the input mechanism) and, in response, the engaging member  108  may engage and displace the locking mechanism  106  in a desired direction to transition the locking mechanism  106  between the locked position and the unlocked position. 
     In operation, the drive member  104  may be subjected to an outside force that applies a load onto the locking mechanism  106 . For example, a component of the device to which the drive member  104  is coupled may exert the outside force on the drive member  104 . In some non-limiting examples, the outside force may occur in more than one direction. In some non-limiting examples, the outside force may be cyclically applied to the drive member  104  with an alternating direction and magnitude. 
     In some non-limiting examples, when the outside force is exerted on the drive member  104 , the corresponding load applied to the locking mechanism  106  can compress the locking mechanism  106  between the driven member  102  and the drive member  104 . This compression applied to the locking mechanism  106  may substantially prevent the locking mechanism  106  from being transitioned, for example, by the engaging member  108  between the locked and unlocked positions. That is, the compression of the locking mechanism  106  between the driven member  102  and the drive member  104  can effectively “lock” the locking mechanism  106  and substantially prevent the engaging member  108  from selectively displacing the locking mechanism  106 . Thus, for certain operating conditions, the outside force applied to the drive member  104  may place the locking mechanism  106  in a loaded state in which the engaging member  108  is substantially prevented from selectively displacing the locking mechanism  106  and transitioning the locking mechanism  106  between the locked and unlocked positions. 
     In some non-limiting examples, the compression of the locking mechanism  106  resulting from the outside force on the drive member  104  may require a prohibitively large input force applied to the engaging member  108  by the input mechanism. The compression of the locking mechanism  106  in the loaded state increases the amount of force required to displace the locking mechanism  106 . In general, a cost associated with the input mechanism is exponentially related to the amount of input force provided thereby. As such, the increased force required to displace the locking mechanism  106  in the loaded state may present a significantly increased cost associated with operating the two-way clutch  100 . 
     In general, the present disclosure provides a predetermined interference that may be applied to the locking mechanism  106  to combat the undesired “locking” thereof in the loaded state and the associated increased input force requirements for the engaging member  108 . In some non-limiting examples, the engaging member  108  may be placed in engagement with the locking mechanism  106 , such that the engaging member  108  provides a predetermined interference to the locking mechanism  106 . For example, the engaging member  108  may be designed to provide the predetermined interference on the locking mechanism  106 , when the locking mechanism  106  is in an unloaded state (i.e., the outside force is not applied to the drive member  104 ). In some non-limiting examples, the predetermined interference provided by the engaging member  108  may displace the locking mechanism  106  away from at least one of the driven member  102  and the drive member  104  such that a gap exists therebetween. In some non-limiting examples, the predetermined interference provided by the engaging member  108  may displace the locking mechanism  106  away from both of the driven member  102  and the drive member  104  such that a gap exists therebetween. 
     The predetermined interference provided on the locking mechanism  106  can make it much easier to displace the locking mechanism  106  in a desired direction (e.g., to transition the locking mechanism  106  between the unlocked and locked positions), which results in a reduced input force required to displace the engaging member  108  and thereby a reduced input force to achieve relative movement between the driven member  102  and the drive member  104 . In addition, the predetermined interference can ensure that the locking mechanism  106  is capable of being displaced (i.e., not “locked” by the compression of the outside force) for a substantial portion of the outside force profile. In this way, the predetermined interference can make operation of the two-way clutch  100  more efficient (e.g., by reducing the required input force and making it easier to displace the locking mechanism  106 ). 
       FIGS. 2A-D  illustrate one non-limiting configuration of the two-way clutch  100  in a rotating two-way clutch application. In the illustrated non-limiting example, the two-way clutch  100  includes the driven member  102 , the drive member  106 , the locking mechanism  106 , and the engaging member  108 . In some non-limiting examples, the two-way clutch  100  may be applied in a mechanical cam phasing application. For example, the driven member  102  may be rotatably coupled to a crankshaft on an internal combustion engine, and the drive member  104  may be rotatably coupled to a camshaft on an internal combustion engine. In some non-limiting examples, the engaging member  108  may be coupled to an actuator (not shown) configured to provide an input force thereto. In application, the actuator may be configured to apply the input force to the engaging member  108  to displace the engaging member  108  into the locking mechanism  106  (e.g., relative to the driven member  102 ) a predetermined amount or distance. The resulting displacement of the locking mechanism  106  may allow the drive member  104  to rotate relative to the driven member  102  (i.e., the camshaft can rotate relative to the crankshaft) in a desired direction to achieve a desired amount of cam phasing (i.e., a rotational offset between the camshaft and the crankshaft). 
     It should be appreciated that the techniques and properties of the two-way clutch  100  described herein may be applied to other rotational and linear two-way clutching applications and the present disclosure is not limited to a mechanical cam phasing application. 
     In the illustrated non-limiting example, the driven member  102  can include a first mating surface  110  arranged adjacent to the locking mechanism  106 . The drive member  104  can include a second mating surface  112  arranged adjacent to the locking mechanism  106 . In the illustrated non-limiting example, the locking mechanism  106  may be arranged between the first mating surface  110  and the second mating surface  112 . The locking mechanism  106  can include a first locking member  114  and a second locking member  116  biased apart from one another by a biasing element  118 . In some non-limiting examples, the first and second locking members  114  and  116  may be in the form of bearings. In some non-limiting examples, the first and second locking members  114  and  116  may be in the form of roller bearings. In some non-limiting examples, the first and second locking members  114  and  116  may take any form configured to conform to a cavity between the first mating surface  110  and the second mating surface  112 , or capable of wedging therebetween. 
     One non-limiting example of the operation of the two-way clutch  100  in a mechanical cam phasing application will be described with reference to  FIGS. 2A-D . Generally, during operation, outside forces may be exerted on the drive member  104 . For example, the drive member  104  may be subjected to cam torque pulses originating from the intake and exhaust valves acting on the camshaft. The cam torque pulses acting on the drive member  104  may vary in direction and magnitude (e.g., cyclically) during operation of the internal combustion engine. 
       FIG. 2A  illustrates the two-way clutch  100  with the locking mechanism  106  in an unloaded state. That is, there is no outside force (e.g., cam torque pulse) applied to the drive member  104 . With the locking mechanism  106  in the unloaded state, the engaging member  108  is designed to engage the locking mechanism  106  such that a predetermined interference is applied thereto. For example, the engaging member  108  can displace the first locking member  114  and the second locking member  116  away from (e.g., out of engagement with) at least one of the first mating surface  110  and the second mating surface  112 . In this way, for example, both of the first and second locking members  114  and  116  may be is capable of being displaced (i.e., not “locked”) by the engaging member  108 . In some non-limiting examples, the predetermined interference may provide a gap between the first locking member  114  and the second locking member  116  and at least one of the first mating surface  110  and the second mating surface  112 . In some non-limiting examples, the predetermined interference may provide a gap between the first locking member  114  and the second locking member  116  and both of the first mating surface  110  and the second mating surface  112 . 
     In any case, the predetermined interference provided by the engaging member  108  can reduce an input force required to be applied on the engaging member  108  to displace one of the first locking member  114  and the second locking member  116 . For example, by providing a gap between the first and second locking members  114  and  116  and at least one of the first mating surface  110  and the second mating surface  112 , a static friction between the first and second locking members  114  and  116  and at least one of the first mating surface  110  and the second mating surface  112  is removed. Thus, a static friction needed to be overcome prior to displacing one of the first and second locking members  114  and  116  is reduced by the predetermined interference (e.g., when compared to convention two-way clutches where the locking members are in contact with both mating surfaces prior to displacement). 
     During operation, an outside force may be applied to the drive member  104  in a first direction, as illustrated in  FIG. 2B . In the illustrated non-limiting example, the outside force may be a torque pulse acting on the drive member  104  in a clockwise direction. When the outside force is applied to the drive member  104  in the first direction, compressive forces F may apply load to the first locking member  114 . For example, the compressive forces F may result from contact between the first locking member  114  and both of the first mating surface  110  and the second mating surface  112 . The compressive forces applied to the first locking member  114  as a result of the outside force on the drive member  104  may “lock” the first locking member  114 . That is, the first locking member  114  may be substantially prevented from being displaced by the engaging member  108 , and relative rotation between the driven member  102  and the drive member  104  may be prevented in the first direction. The second locking member  116 , however, may be supported by the engaging member  108  and the predetermined interference provided thereby can maintain a clearance, or gap, between the second locking member  116  and at least one of the first mating surface  110  and the second mating surface  112 . Thus, the predetermined interference can maintain the second locking member  116  in an “unlocked” state, where it is not compressed between the first and second mating surfaces  110  and  112  and still easily displaced by the engaging member  108 , if desired. In this way, for example, relative rotation between the driven member  102  and the drive member  104  may be allowable (e.g., if the engaging member  108  is moved relative to the drive member  102 ) in a second direction opposite to the first direction. 
       FIG. 2C  illustrates the two-way clutch  100  once the outside force applied to the drive member  104  in the first direction is removed. With the outside force removed, the compressive forces on the first locking member  114  can be removed and the locking mechanism  106  may return to the unloaded state. Thus, the first locking member  114  can return to a state where it is capable of being displaced by the engaging member  108 . 
     During operation, an outside force may be applied to the drive member  104  in a second direction, as illustrated in  FIG. 2D . In some non-limiting examples, the outside force in the second direction may occur at a different time than the outside force in the first direction ( FIG. 2B ). In some non-limiting examples, the outside force applied to the drive member  104  may be cyclic in magnitude and direction. In the illustrated non-limiting example, the outside force may be a torque pulse acting on the drive member  104  in a counterclockwise direction. When the outside force is applied to the drive member  104  in the second direction, compressive forces F may apply load to the second locking member  116 . For example, the compressive forces F may result from contact between the second locking member  116  and both of the first mating surface  110  and the second mating surface  112 . The compressive forces applied to the second locking member  116  as a result of the outside force on the drive member  104  may “lock” the second locking member  116 . That is, the second locking member  116  may be substantially prevented from being displaced by the engaging member  108 , and relative rotation between the driven member  102  and the drive member  104  may be prevented in the second direction. The first locking member  114 , however, may be supported by the engaging member  108  and the predetermined interference provided thereby can maintain a clearance, or gap, between the first locking member  114  and at least one of the first mating surface  110  and the second mating surface  112 . Thus, the predetermined interference can maintain the first locking member  114  in an “unlocked” state, where it is not compressed between the first and second mating surfaces  110  and  112  and still easily displaced by the engaging member  108 , if desired. In this way, for example, relative rotation between the driven member  102  and the drive member  104  may be allowable (e.g., if the engaging member  108  is moved relative to the drive member  102 ) in a second direction opposite to the first direction. 
     As illustrated in  FIGS. 2A-2D , the predetermined interference provided on the locking mechanism  106  by the engaging member  108  may maintain each of the first locking member  114  and the second locking member  116  “unlocked,” or capable of being displaced, for example, at least half of the outside force cycle. That is, the first locking member  114  may be maintained in the “unlocked” state during outside forces in the second direction, and the second locking member  116  may be maintained in the “unlocked” state during outside forces in the first direction. In this way, the input force requirements of the engaging member  108 , for example, to allow relative rotation between the driven member  102  and the drive member  104  may be significantly reduced when compared to conventional two-way clutches, or mechanical cam phasing systems. 
       FIGS. 3A-D  illustrate one non-limiting example of a convention two-way clutch  200 . Similar components between the two-way clutch  100  and the convention two-way clutch  200  are identified using like reference numerals in the  200 &#39;s. As illustrated in  FIGS. 3A-D , the conventional two-way clutch  200  does not apply a predetermined interference on the locking mechanism  206 . The lack of a predetermined interference may lead to the locking mechanism  206  being “locked,” or substantially inhibited from being displaced by the engaging member  208  for most of the outside force cycle. 
     For example, as locking mechanism  206  transitions from the unloaded state ( FIG. 3A ) to a state where an outside force is applied to the drive member  204  ( FIG. 3B ), compressive forces F may be applied to the first locking member  114 , thereby “locking” the first locking member  114  between the first mating surface  210  and the second mating surface  212 . At substantially the same time, the biasing element  218  can push the second locking member  216  into contact with the first mating surface  210  and the second mating surface  212 , giving it a displacement d. Therefore, as the outside force is removed ( FIG. 3C ), the compressive forces on the first locking member  214  are reduced, but the second locking member  216  displaced into a position where it is subjected to compressive forces F. As illustrated in  FIG. 3C , once the outside force is removed, both of the first locking member  214  and the second locking member  216  may be subjected to compressive forces, which “lock,” or substantially prevent the first and second locking members  214  and  216  from being displaced. With some compressive forces being applied to both of the first and second locking members  214  and  216 , a substantially increased input force may be required to displace either the first locking member  214  or the second locking member  216 . 
     When an outside force is applied to the drive member  204  in a second direction ( FIG. 3D ), compressive forces F can “lock” the second locking member  216 . The first locking member  214  may eventually be “unlocked,” but this will only occur for extremely high magnitudes of the outside force, which may last for only short time periods. In particular, in a cam phasing application, the highest torque pulses typically last for very short periods of time in most engine applications. 
     Thus, the application of a predetermined interference on the locking mechanism of a two-way clutch may provide significant advantages over conventional two-way clutches. For example, the predetermined interference can reduce an input force required to enable relative displacement between a driven member and a drive member. Alternatively or additionally, the predetermined interference can facilitate efficient transitions between operating modes of the two-way clutch (e.g., a locked state where relative rotation between the drive and driven members is inhibited and an unlocked state where relative rotation between the drive and driven members is enabled). In applications where a cyclic outside force may be applied to a drive member of the two-way clutch, the predetermined interference can ensure that the locking mechanism is capable of displacing in a direction opposite to the outside force. 
     Within this specification embodiments have been described in a way which enables a clear and concise specification to be written, but it is intended and will be appreciated that embodiments may be variously combined or separated without parting from the invention. For example, it will be appreciated that all preferred features described herein are applicable to all aspects of the invention described herein. 
     Thus, while the invention has been described in connection with particular embodiments and examples, the invention is not necessarily so limited, and that numerous other embodiments, examples, uses, modifications and departures from the embodiments, examples and uses are intended to be encompassed by the claims attached hereto. The entire disclosure of each patent and publication cited herein is incorporated by reference, as if each such patent or publication were individually incorporated by reference herein. 
     Various features and advantages of the invention are set forth in the following claims.