VALVE BRIDGE WITH INTEGRATED SLAB BUSHING FOR DEADLINE AND ENGINE BRAKING

Abstract

A rocker arm assembly for a motor with a base body rotatable about a shaft. The base body has a roller end and a valve end. A first switchable caster assembly is arranged in the valve end. The first switchable caster assembly has a distal end configured to selectively actuate a first valve. A second switchable caster assembly is arranged in the valve end. The second switchable caster assembly has a distal end configured to engage a valve bridge assembly. The valve bridge assembly is configured to actuate a second valve.

Description

priority

[0001] This application claims the benefit of U.S. Provisional Patent Application Serial No. 63 / 319,902, filed March 15, 2022, the contents of which are incorporated herein by reference in their entirety. Field of the invention

[0002] The present application generally relates to a valve bridge for use in a valve train assembly. More particularly, this application relates to a valve bridge configured for valve deactivation and engine braking. background

[0003] Rocker arms are used in many internal combustion engines to convert the rotary motion of the cams into a linear motion suitable for opening and closing engine valves. Deactivating a valve allows the rocker arm to move without transmitting any movement to the valve.

[0004] The present application provides a device for deactivating valves for cylinder deactivation and engine braking (EB). Brief description of the invention

[0005] Provided is a rocker arm assembly for an engine comprising a base body rotatable about a shaft. The base body has a roller end and a valve end. A first switchable castellation assembly is arranged in the valve end. The first switchable castellation assembly has a distal end configured to selectively move a first valve. A second switchable castellation assembly is arranged in the valve end. The second switchable castellation assembly has a distal end configured to engage a valve bridge assembly. The valve bridge assembly is configured to engage and actuate a second valve.

[0006] In the aforementioned rocker arm arrangement, the first valve is assigned to an engine braking function.

[0007] In the aforementioned rocker arm arrangement, the valve bridge arrangement is designed to engage the first valve and actuate it.

[0008] In the aforementioned rocker arm arrangement, the first valve and the second valve are assigned a cylinder deactivation function.

[0009] In the aforementioned rocker arm arrangement, the first valve is movable independently of the valve bridge arrangement.

[0010] In the aforementioned rocker arm arrangement, the first switchable castellation arrangement is arranged closer to the shaft than the second switchable castellation arrangement.

[0011] In the aforementioned rocker arm assembly, the first switchable castellation assembly and the second switchable castellation assembly each comprise a lost motion shaft. The lost motion shaft is configured to transmit a lift profile to a valve end. A switchable castellation device is further provided. The switchable castellation device comprises a rotatable first keyway bushing and a keyway body. The first keyway bushing is configured to switch between a locked position and an unlocked position. A lost motion is obtained by sliding the lost motion shaft when the first keyway bushing is in the unlocked position.

[0012] In the aforementioned rocker arm assembly, the rotatable first keyway bushing of the first switchable caster assembly has a height equal to a sum of a distance required for a backlash of the first valve during an engine braking function of the first valve and a distance required for a backlash of the first valve during a cylinder deactivation function of the first valve.

[0013] In the aforementioned rocker arm assembly, the rotatable first keyway bushing of the second switchable caster assembly has a height equal to a sum of a distance required for a lost motion of the second valve during a cylinder deactivation function of the second valve.

[0014] In the aforementioned rocker arm assembly, a lower surface of the first keyway bushing is offset from an upper surface of the keyway body by a distance required for lost motion of the second valve during an engine braking function of the first valve.

[0015] In the aforementioned rocker arm arrangement, a basic position of the first keyway bushing of the first switchable caster arrangement is the unlocking position.

[0016] In the aforementioned rocker arm arrangement, a basic position of the first keyway bushing of the second switchable caster arrangement is the locking position.

[0017] In the aforementioned rocker arm assembly, the first switchable caster assembly and the second switchable caster assembly each further comprise a lost motion spring. The lost motion spring is configured to bias the lost motion shaft into a fully extended position. The lost motion spring is also configured to collapse during lost motion.

[0018] In the aforementioned rocker arm assembly, the first switchable castellation assembly and the second switchable castellation assembly each comprise an actuator for rotating the first keyway bushing between the locking position and the unlocking position.

[0019] Further, methods are provided for operating a rocker arm assembly during an engine braking function and an engine braking backlash function. The rocker arm assembly includes a base body rotatable about a shaft. The base body has a roller end and a valve end. A first switchable castellation assembly is disposed in the valve end. The first switchable castellation assembly has a distal end configured to selectively move a first valve. The first switchable castellation assembly is movable between a deactivated position in which rotation of the base body about the shaft is not transmitted to the first valve via the first switchable castellation assembly, and an activated position in which rotation of the base body about the shaft is transmitted to the first valve via the first switchable castellation assembly. A second switchable castellation assembly is disposed in the valve end.The second switchable castellation arrangement has a distal end configured to engage a valve bridge arrangement. The valve bridge arrangement is configured to engage and actuate a second valve. The second switchable castellation arrangement is movable between an engaged position, in which the rotation of the base body about the shaft is transmitted to the second valve via the valve bridge arrangement and the second switchable castellation arrangement, and a deactivated position, in which the rotation of the base body about the shaft is not transmitted to the second valve via the valve bridge arrangement and the second switchable castellation arrangement.The method comprises, for the engine braking function, 1) moving the first switchable castellation assembly to the engaged position; and 2) rotating the base body a predetermined distance sufficient to actuate the first valve via the first switchable castellation assembly for the engine braking function, wherein the second switchable castellation assembly collapses inwardly to prevent motion transmission via the second switchable castellation assembly to the valve bridge assembly.For the engine braking lost motion function, 1) moving the first switchable castellation assembly to the deactivated position; and 2) rotating the base body a predetermined distance sufficient to actuate the first valve via the first switchable castellation assembly for the engine braking function, wherein the first switchable castellation assembly experiences lost motion and motion is not transmitted via the first switchable castellation assembly to the first valve, and wherein the second switchable castellation assembly collapses inwardly to prevent motion transmission via the second switchable castellation assembly to the valve bridge assembly.

[0020] In the aforementioned method, operating the rocker arm assembly during a normal operating mode and a cylinder deactivation function further comprises, for the normal operating mode: 1) moving the first switchable castellation assembly to the deactivated position and the second switchable castellation assembly to the activated position, and 2) rotating the base body a predetermined distance sufficient to actuate the second valve via the second switchable castellation assembly for the normal operating mode, wherein the first switchable castellation assembly experiences lost motion and the movement is not transmitted to the first valve via the first switchable castellation assembly, and for the cylinder deactivation function: 1) moving the first switchable castellation assembly to the deactivated position and the second switchable castellation assembly to the deactivated position;and 2) rotating the base body by the predetermined distance sufficient to actuate the second valve via the second switchable castellation arrangement for the normal operating mode, wherein the first valve experiences lost motion via the first switchable castellation arrangement and the second valve experiences lost motion via the second switchable castellation arrangement;

[0021] In the aforementioned method, the first switchable castellation arrangement and the second switchable castellation arrangement each comprise a lost motion shaft. The lost motion shaft is configured to transmit a stroke profile to a valve end. Furthermore, a switchable castellation device is provided. The switchable castellation device comprises a rotatable first keyway bushing and a keyway body. The first keyway bushing is configured to switch between a locking position and an unlocking position. A lost motion is obtained by displacing the lost motion shaft when the first keyway bushing is in the unlocking position.

[0022] In the above method, the rotatable first keyway bushing of the first switchable castellation assembly has a height equal to a sum of a distance required for backlash of the first valve during the engine braking backlash function and a distance required for backlash of the first valve during the cylinder deactivation function.

[0023] In the above method, the rotatable first keyway bushing of the second switchable caster assembly has a height equal to a sum of a distance required for a lost motion of the second valve during the cylinder deactivation function of the second valve.

[0024] In the above method, the collapse of the second switchable castellation assembly during the engine braking lost motion function is achieved by offsetting a lower surface of the first keyway bushing from an upper surface of the keyway body by a predetermined distance. Brief description of the drawings The Fig. 1 is a perspective view of a rocker arm assembly with two integrated castellation assemblies; the Fig. 2 is a perspective view of the castellation arrangement of the Fig. 1; the Fig. 3 is a sectional view of the castellation arrangement of the Fig. 2 along line 3-3; the Fig. 4 is an end view of a first keyway bushing of the castellation assembly of the Fig. 2; the Fig. 5 is an end view of a guide of the castellation assembly of the Fig. 2; the Fig. 6 is an end view of a keyway body of the castellation assembly of the Fig. 2; the Fig. 7 is a perspective view of a first keyway bushing and keyway body in a locking position; the Fig. 8 is a perspective view of a first keyway bushing and keyway body in an unlocking position; the Fig. 9 is a perspective view of a first keyway bushing and a keyway body in the unlocked position, with the keyway body partially received in the first keyway bushing; the Fig. 10 is a perspective view of the castellation arrangement of the Fig. 2 with an actuator; and the Fig. 11 is a diagram of a displacement of a surface of a cam versus the cam angle. Detailed description

[0025] The following is a description of the disclosure; however, aspects may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Furthermore, the following examples may be provided alone or in combination with any example discussed herein, or any combination of the examples discussed herein. Directional references such as "left" and "right" are provided for ease of reference to the figures.

[0026] With reference to the Fig. 1, the rocker arm assembly 10 is shown to include a rocker arm 12 configured to rotate about a shaft 14. A roller end 16 of the rocker arm 12 is configured to engage a cam 18 that causes the rocker arm 12 to rotate about the shaft 14. A valve end 22 of the rocker arm 12 is configured to selectively drive the valves 24, 26 as the rocker arm 12 rotates about the shaft 14.

[0027] A valve bridge assembly 50 is configured to engage the valve end 22 of the rocker arm 12. A body 60 of the valve bridge assembly 50 is configured to engage the valves 24, 26 so that the valve bridge assembly 50 controls the rotational movement of the rocker arm 12 ( Fig. 1) into a vertical movement of the valves 24, 26.

[0028] As described in detail below, a movable insert 62 is provided to allow the valve 24 to move relative to the valve bridge assembly 50 during engine braking. A first switchable castellation assembly 100 is provided to move the valve 24 relative to the valve bridge assembly 50. A second switchable castellation assembly 200 is provided to move both valves 24, 26 across the valve bridge assembly 50.

[0029] The switchable castellation arrangement of PCT / EP2022 / 025147 is hereby incorporated herein in its entirety. The following is a brief description of the first and second switchable castellation arrangements 100, 200. For the sake of brevity, only the first switchable castellation arrangement 100 is described below. The second switchable castellation arrangement 200 is identical to the first switchable castellation arrangement 100, except for the exceptions noted below.

[0030] With reference to the Fig. 2 and Fig. 3, the first switchable castellation device 100 lies substantially along an axis AA and comprises a lost motion shaft 111, a play adjustment screw 112, a lost motion spring 113, a first keyway bushing 114, a guide 115, and a keyway body 116. Optionally, the lost motion shaft 111 may comprise an end flare 117 to which an optional contact device 118 is mounted; for example, a press foot, an elephant foot, a pin, or a similar device, which may then bear against the movable insert 62 or the valve bridge 50 ( Fig. 1), attached to one end of the lost motion shaft 111. The lash adjustment screw 112 and the keyway body 116 may be secured to the lost motion shaft 111 by interference fit, crimp fit, threads, or other fasteners.

[0031] The lost motion shaft 111 is designed to impart a movement to the movable insert 62 or the valve bridge 50 ( Fig. 1) and is configured to slide in a lost motion mode. As described in more detail below, the first splined bushing 114 is arranged to slide along at least a portion of the axial length of the lost motion shaft 111 along the axis AA. The lash adjustment screw 112 allows the amount of mechanical lash to be adjusted. The lost motion spring 113 is arranged along the axial length of the lost motion shaft 111 or otherwise slipped onto the lost motion shaft 111 and can accommodate the movement of a valve lift event without causing a valve to open until a lift limit—formed, for example, on the first switchable castellation device 100 itself or within the structure in which the first switchable castellation device 100 is housed—is reached.

[0032] With reference to the Fig. 3, the first spline bushing 114 is an annular member having a first spline bore 131. The first spline bushing 114 has an inner diameter sized larger than the outer diameter of the spline body 116 to allow axial movement of the spline body 116 through the first spline bushing 114. The first spline bushing 114 is slidable in the axial direction of the lost motion shaft 111. The first spline bushing 114 further includes a first actuator interface 132 disposed on at least a portion of the outer periphery of the first spline bushing 114. A first spline interface 133 is disposed on at least a portion of the inner periphery of the first spline bushing 114.The first keyway interface 133 is capable of alternately allowing the keyway body 116 to slide into at least a portion of the first keyway bushing 114 in one position and blocking the keyway body 116 from sliding into at least a portion of the first keyway bushing 114 in another position.

[0033] The first keyway interface 133 is contoured to define mechanisms or features that enable the first keyway bushing 114 to receive or lock the keyway body 116. As described in detail below, the first keyway interface 133 further includes a keyway index 134 for receiving a keyway body index 153 of the keyway body 116. The first keyway interface 133, including the optional keyway index 134, is formed by a plurality of first keyways 135 that extend in the axial direction of the first keyway bushing 114 and parallel to the lost motion shaft 111. As shown in the Fig. 4, the grooves 135 appear, when viewed from above, as teeth and gaps that complement the keyway body 116 to allow the first keyway bushing 114 to receive at least a portion of the keyway body 116 or to prevent the first keyway bushing 114 from receiving at least a portion of the keyway body 116. Although the first keyway bushing 114 in the Fig. 2 to 4 is generally shown as a cylindrical ring, it is also contemplated that the first spline bushing 114 may also have other shapes as long as the first spline bushing 114 slides along the lost motion shaft 111.

[0034] With reference to the Fig. 5, the guide 115 comprises an angularly fixed ring having an inner diameter that is larger than the outer diameter of the keyway body 116. The guide 115 includes a guide bore 141 configured to receive the keyway body 116. The guide 115 ensures alignment of the keyway body 116 relative to the first keyway bushing 114, thereby preventing angular drift or angular movement of the keyway body 116. The guide 115 further includes a guide notch 142 along at least a portion of the outer periphery of the guide 115 and a guide interface 143 disposed on at least a portion of the inner periphery of the guide 115.

[0035] Although the guide notch 142 is illustrated as a rectangular projection extending radially from an outer surface of the guide 115, it is contemplated that the guide notch 142 may have other shapes, or even, instead of a projection, a depression or depressions along at least a portion of the outer surface of the guide 115. The guide notch 142 may be provided with a corresponding slot, groove, divot, tab, projection, or other feature on the rocker arm assembly 10 ( Fig. 1) fit together.

[0036] The guide interface 143 is contoured to define features that enable the guide 115 to receive the keyway body 116. As described further below, the guide interface 143 further includes a guide index 144 for aligning the keyway body 116 with the first keyway bushing 114. The guide interface 143, including the guide index 144, is formed by a plurality of guide grooves 145 that extend in the axial direction of the guide 115 and parallel to the lost motion shaft 111. As shown in the Fig. 5, the grooves 145 appear, when viewed from above, as teeth and gaps that align with the keyway body 116 and allow the keyway body 116 to slide through or pass through at least a portion of the guide 115. Although the guide 115 in the Fig. 2, Fig. 3 and Fig. 5 as a cylindrical ring, it is contemplated that the guide 115 may have other shapes.

[0037] With reference to the Fig. 6, the keyway body 116 is an annular body having a keyway bore 151 extending axially therethrough. The outer diameter of the keyway body 116 is smaller than the inner diameter of the keyway bushing 114 and the guide 115, allowing the keyway body 116 to slide axially through the keyway bushing 114 and the guide 115. The keyway body bore 151 is sized to receive the lost motion shaft 111. As previously mentioned, the keyway body 116 may be attached to the lost motion shaft 111 via threads or other fastening means. The keyway body 116 may further include a keyway interface 152 along at least a portion of the outer periphery of the keyway body 116.In one position, the keyway body interface 152 enables the keyway body 116 to slidably engage at least a portion of the first keyway bushing 114, and in another position, the keyway body interface 152 enables the keyway body 116 to be blocked from sliding into the keyway bushing 114.

[0038] The keyway body interface 152 is contoured to define features that allow or block the sliding of the keyway body 116 through the keyway bushing 114. The keyway body interface 152 also includes a keyway body index 153 for aligning the keyway body 116 with the guide index 144 of the guide 115. The keyway body interface 152, including the keyway body index 153, is formed by a plurality of keyway body grooves 154 that run along the axial length of the keyway body 116 parallel to the lost motion shaft 111. As shown in the Fig. 6, the grooves 154 appear, when viewed from above, as teeth and spaces that complement the first keyway interface 133 and the pilot interface 143. The keyway body index 153 may be a space or tooth—or an arrangement of teeth and spaces—that can slidably cooperate with the first keyway index 134 and the pilot index 144. Similarly, the pilot index 144 is a complementary formation that can slidably cooperate with the keyway body index 153. The first keyway index 134 is also a complementary tooth or space, or a set of teeth and spaces that can slidably cooperate with the keyway body index 153.

[0039] Although the first keyway bushing 114, the guide 115, and the keyway body 116 are illustrated as cylindrical rings, it is contemplated that they may have other shapes. Likewise, the first keyway interface 133, the guide interface 143, and the keyway body interface 152 are illustrated as intermeshing teeth with complementary spacing. It is contemplated that the aforementioned features may have other positive engagement configurations.

[0040] The keyway body 116 remains within at least a portion of the guide 115 throughout its movement. This allows the guide 115 to maintain the angular orientation of the keyway body 116. Keeping the keyway body 116 slid into at least a portion of the guide 115 can be used alone or in conjunction with the indices 134, 144, 153 to maintain the angular orientation of the keyway body 116.

[0041] The dimensions of the keyway body 116 and the first keyway bushing 114 are selected such that the grooves 135, 145, and 154 allow the entire keyway body 116 to slide into the first keyway bushing 114, thereby increasing the amount of movement accommodated by the first switchable castellation device 100. The grooves 135, 145, and 154 also result in improved structural durability, allowing the first keyway bushing 114 and keyway body 116 to be formed with a greater axial length, which in turn allows the first switchable castellation device 100 to accommodate a greater degree of backlash.

[0042] The Fig. Figures 7 to 9 illustrate how the first keyway bushing 114 interacts with the keyway body 116. In these figures, the guide 115 is removed so that the view of the first keyway bushing 114 and the keyway body 116 is not obstructed. Fig. 7, an actuator (not shown) has driven or engaged the first actuator interface 132 to rotate the first keyway bushing 114 into a locking position. In the locking position, the first keyway bushing 114 is oriented relative to the keyway body 116 such that the first keyway interface 133 is aligned with the keyway body interface 152, preventing the first keyway interface 133 and the keyway body interface 152 from sliding past each other. Therefore, in the locking position, the first keyway bushing 114 cannot slide into the keyway body 116. This results in a short lost motion mode.

[0043] With reference to the Fig. 8, an actuator (not shown) has driven the first actuator interface 132 to rotate the first keyway bushing 114 into an unlocked position. In this unlocked position, the first keyway bushing 114 is oriented relative to the keyway body 116 such that the first keyway interface 133 is aligned with the keyway body interface 152, allowing the first keyway interface 133 and the keyway body interface 152 to slide past each other. Therefore, in the unlocked position, the first keyway bushing 114 can slide into the keyway body 116. This results in a long backlash mode, and the amount of backlash accommodated is increased compared to the first switchable castellation device 100 in a short backlash mode.

[0044] Reference to the Fig. 9, the first keyway bushing 114 is still in the unlocked position. When force is applied to the first switchable castellation device 100, the keyway body 116 and the first keyway bore 131 of the first keyway bushing 114 are pushed together. The lost motion spring 113 absorbs at least a portion of the retracting movement.

[0045] The following refers to the Fig. 10, which illustrates an optional actuator 191. The actuator 191 may be hydraulically, pneumatically, or electromagnetically controlled. The actuator 191, in turn, may drive or rotate the first keyway bushing 114 clockwise or counterclockwise with a rack and pinion, but other actuation arrangements may also be employed. The actuator 191 includes an interface 192 that mates with the first actuator interface 132 of the first keyway bushing 114. Via the interface 192 and the first actuator interface 132, the actuator 191 may rotate the first keyway bushing 114 to switch between a locked position and an unlocked position. Alternative actuators that are compatible with this are described, for example, in WO2021213703, PCT / EP2021 / 025421, WO2021164950, which are hereby incorporated in their entirety by reference.

[0046] As previously mentioned, the description of the second switchable castellation assembly 200 is identical to the above description of the first switchable castellation assembly 100 and will not be repeated for brevity. Similar reference numerals, incremented by 200, are used below to refer to similar components of the second switchable castellation assembly 200.

[0047] With further reference to the Fig. 1, the first and second switchable caster arrangements 100, 200 are arranged in the same rocker arm arrangement 10, so that the engine brake function ("EB function") and the cylinder deactivation function ("CDA function") are integrated into a common rocker arm. This integrated arrangement is particularly applicable to a single overhead cam ("SOHC") engine, in which the EB function is configured to open only valve 24, whereas the rocker arm arrangement 10 opens both valves 24, 26 via the valve bridge arrangement 50 during normal valve lift.

[0048] The first switchable castellation assembly 100 is used for the EB function and the EB lost motion function and only affects the valve 24. The first switchable castellation assembly 100 is arranged closer to the shaft 14 than the second switchable castellation assembly 200. As described in detail above, the first switchable castellation assembly 100 is arranged such that the home position of the first keyway bushing 114 is the deactivated or unlocked position ( Fig. 8 and Fig. 9). In this position, the movement of the rocker arm 12 about the shaft 14 does not transmit any movement to the valve 24 via the first switchable caster arrangement 100.

[0049] The first keyway bushing 114 is configured to have a height H1 corresponding to a total backlash available for the first switchable castellation arrangement 100. Referring to the Fig. 11, the height H1 is chosen so that it corresponds to the sum of the distance required for the EB backlash function LM EB required and the distance required for the CDA function LM CDA required. The height H1 is determined based on the EB backlash LM EB and the CDA backlash LM CDA - measured on the cam 18 - calculated and adjusted to the distance X R between the roller 16 and the shaft 14 and to the distance X1 between the first switchable castellation arrangement 100 and the shaft 14, see Fig. 1. The following equation can be used to represent this relationship: H1=(LMEB+LMCDA)×(X1 / XR)

[0050] During the EB function, the first keyway bushing 114 of the first switchable castellation arrangement 100 is rotated into the locking position ( Fig. 7), so that rotation of the rocker arm assembly 10 about the shaft 14 transmits movement to the valve end 22. This movement is transmitted from the first switchable castellation assembly 100 through the movable insert 62 to the valve 24 to implement the EB function.

[0051] As already mentioned, the first switchable castellation arrangement 100 is used for the EB function and the EB lost motion function and only affects the valve 24. During normal operation or when the CDA function is activated, the first keyway bushing 114 returns to the unlocked position ( Fig. 8 and Fig. 9), so that the first switchable castellation arrangement 100 does not cause any movement of the valve 24, i.e., the valve 24 experiences lost motion via the first switchable castellation arrangement 100. When the first switchable castellation arrangement 100 is in the unlocked position, the movement or lost motion of the valve 24 is controlled by the second switchable castellation arrangement 200, as described in detail below.

[0052] The second switchable castellation assembly 200 is used for normal operation and the CDA function for both valves 24, 26. In the illustrated embodiment, the second switchable castellation assembly 200 is arranged farther from the shaft 14 than the first switchable castellation assembly 100. The second switchable castellation assembly 200 is configured such that the first keyway bushing 214, as described in detail above, is in the locking position ( Fig. 7). In this position, the movement of the rocker arm 12 about the shaft 14 is transmitted to the first keyway bushing 214.

[0053] As in the Fig. 1, an end surface of the first keyway bushing 214 is spaced from an opposite end surface of the keyway body 216 by a distance D EB offset. The distance D EB is selected to correspond to the maximum distance by which the end face of the first keyway bushing 214 moves during the EB function. In this regard, the second switchable roller assembly 200 falls by the distance D upon movement of the rocker arm 12 during the EB function. EB inwards, whereby no movement is transmitted to the valve bridge 50.

[0054] A height H2 of the first keyway bushing 214 corresponds to the backlash experienced by the valve bridge assembly 50 during CDA function. Similar to H1, as explained in detail above, the height H2 is determined based on the CDA backlash LM CDA - measured on the cam 18 - calculated and adjusted to the distance X R between the roller 16 and the shaft 14 and to the distance X2 between the second switchable castellation arrangement 200 and the shaft 14, see Fig. 1. The following equation can be used to represent this relationship: H2=(LMEB+LMCDA)×(X2 / XR)

[0055] During normal operation, the first keyway bushing 114 is rotated into the locking position ( Fig. 7), so that rotation of the rocker arm assembly 10 about the shaft 14 transmits movement to the valve end 22. This movement is transmitted through the second switchable castellation assembly 200 to the valve bridge 50, which in turn moves the two valves 24, 26.

[0056] During the CDA function, the first keyway bushing 214 is turned to the unlocking position ( Fig. 8 and Fig. 9), so that rotation of the rocker arm assembly 10 about the shaft 14 does not transmit movement to the valve end 22. Instead, the keyway body 216 moves into the first keyway bushing 214 and the second switchable caster assembly 200, and both valves 24, 26 experience lost motion (via the valve bridge assembly 50).

[0057] In summary, the first switchable castellation assembly 100 and the second switchable castellation assembly 200 are configured such that normally the first switchable castellation assembly 100 is in a deactivated mode and the second switchable castellation assembly 200 is in an activated mode. When the first and second switchable castellation assemblies 100, 200 are in this mode, movement of the rocker arm 12 causes power to be transmitted to the valves 24, 26 only from the second switchable castellation assembly 200. The second switchable castellation assembly 200 can be deactivated (by moving the first keyway bushing 214 to the unlocked position) to implement the CDA function.

[0058] When an EB function is desired, the first keyway bushing 114 of the first switchable castellation assembly 100 is moved to the locked position. In this position, the movement of the rocker arm 12 causes the first switchable castellation assembly 100 to move the valve 24 over the movable insert 62 without causing movement of the bridge 50. Since the first keyway bushing 214 is displaced by the distance D EB is offset from the keyway body 216, no force is transmitted to the valve bridge 50 by the second switchable castellation arrangement 200.

[0059] When it is desired to move both valves 24, 26, the first keyway bushing 114 of the first switchable castellation assembly 100 is moved to the unlocked position, and the first keyway bushing 214 of the second switchable castellation assembly 200 is moved to the locked position. In this position, the second switchable castellation assembly 200 controls the movement of the valves 24, 26 via the valve bridge 50.

[0060] In the illustrated embodiments, the first switchable castellation assembly 100 is disposed closer to the shaft 14 than the second switchable castellation assembly 200. It is contemplated that the first and second switchable castellation assemblies 100, 200 may be disposed equidistant from the shaft 14, or that the first switchable castellation assembly 100 may be spaced farther from the shaft 14 than the second switchable castellation assembly 200.

[0061] It will be apparent to those skilled in the art that various modifications and variations may be made without departing from the spirit and scope of the claimed invention. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] US 63 / 319,902

[0001] EP 2022 / 025147

[0029] WO 2021213703

[0045] EP 2021 / 025421

[0045] WO 2021164950

[0045]

Claims

[1] Rocker arm assembly for an engine, comprising: a base body rotatable about a shaft, the base body having a roller end and a valve end; a first switchable castellation assembly disposed in the valve end, the first switchable castellation assembly having a distal end configured to selectively move a first valve; and a second switchable castellation assembly disposed in the valve end, the second switchable castellation assembly having a distal end configured to engage a valve bridge assembly, the valve bridge assembly configured to engage and actuate a second valve. [2] Rocker arm assembly according to claim 1, wherein the first valve is associated with an engine braking function. [3] A rocker arm assembly according to claim 1 or claim 2, wherein the valve bridge assembly is adapted to engage and actuate the first valve. [4] Rocker arm assembly according to claim 3, wherein the first valve and the second valve are associated with a cylinder deactivation function. [5] Rocker arm assembly according to claim 3 or claim 4, wherein the first valve is movable independently of the valve bridge assembly. [6] Rocker arm assembly according to one of claims 1 to 5, wherein the first switchable castellation assembly is arranged closer to the shaft than the second switchable castellation assembly. [7] Rocker arm assembly according to one of claims 1 to 6, wherein the first switchable castellation assembly and the second switchable castellation assembly each comprise: a lost motion shaft, the lost motion shaft being adapted to transmit a lift profile to a valve end; and a switchable castellation device, the switchable castellation device comprising: a rotatable first keyway bushing, and a keyway body, wherein the first spline bushing is configured to switch between a locking position and an unlocking position, and wherein a lost motion is obtained by sliding the lost motion shaft when the first spline bushing is in the unlocking position. [8] The rocker arm assembly of claim 7, wherein the rotatable first spline bushing of the first switchable caster assembly has a height equal to a sum of a distance required for backlash of the first valve during an engine braking function of the first valve and a distance required for backlash of the first valve during a cylinder deactivation function of the first valve. [9] A rocker arm assembly according to claim 7 or claim 8, wherein the rotatable first spline bushing of the second switchable castellation assembly has a height equal to a sum of a distance required for lost motion of the second valve during a cylinder deactivation function of the second valve. [10] Rocker arm assembly according to one of claims 7 to 9, wherein a lower surface of the first keyway bushing is offset from an upper surface of the keyway body by a distance required for lost motion of the second valve during an engine braking function of the first valve. [11] Rocker arm assembly according to one of claims 7 to 10, wherein a basic position of the first keyway bushing of the first switchable caster assembly is the unlocking position. [12] Rocker arm assembly according to one of claims 7 to 11, wherein a basic position of the first keyway bushing of the second switchable caster assembly is the locking position. [13] Rocker arm assembly according to one of claims 7 to 12, wherein the first switchable castellation assembly and the second switchable castellation assembly each further comprise a lost motion spring, the lost motion spring being adapted to bias the lost motion shaft to a fully extended position, and the lost motion spring being adapted to collapse during lost motion. [14] A rocker arm assembly according to any one of claims 7 to 13, wherein the first switchable castellation assembly and the second switchable castellation assembly each further comprise an actuator for rotating the first keyway bushing between the locking position and the unlocking position. [15] A method of operating a rocker arm assembly during an engine braking function and an engine braking lost motion function, the rocker arm assembly comprising: a base body rotatable about a shaft, the base body having a roller end and a valve end; a first switchable castellation assembly disposed in the valve end, the first switchable castellation assembly having a distal end configured to selectively move a first valve, the first switchable castellation assembly being movable between a deactivated position in which rotation of the base body about the shaft is not transmitted to the first valve via the first switchable castellation assembly, and an activated position in which rotation of the base body about the shaft is transmitted to the first valve via the first switchable castellation assembly; and a second switchable castellation assembly,which is arranged in the valve end, wherein the second switchable castellation arrangement has a distal end which is configured to engage a valve bridge arrangement, wherein the valve bridge arrangement is configured to engage and actuate a second valve, wherein the second switchable castellation arrangement is movable between an switched-on position in which the rotation of the base body about the shaft is transmitted via the valve bridge arrangement and the second switchable castellation arrangement to the second valve, and a switched-off position in which the rotation of the base body about the shaft is not transmitted via the valve bridge arrangement and the second switchable castellation arrangement to the second valve, the method comprising: for the engine braking function: 1) Moving the first switchable castellation assembly to the switched position; and 2) rotating the base body by a predetermined distance sufficient to actuate the first valve via the first switchable castellation arrangement for the engine braking function, wherein the second switchable castellation arrangement collapses inwardly to prevent transmission of motion via the second switchable castellation arrangement to the valve bridge arrangement, and for the engine braking backlash function: 1) moving the first switchable castellation assembly to the deactivated position; and 2) Rotating the base body by the predetermined distance sufficient to actuate the first valve via the first switchable castellation arrangement for the engine braking function, wherein the first switchable castellation arrangement experiences a lost motion and the movement is not transmitted via the first switchable castellation arrangement to the first valve, and wherein the second switchable castellation arrangement collapses inward to prevent movement from being transmitted via the second switchable castellation arrangement to the valve bridge arrangement, [16] The method of claim 15, further operating the rocker arm assembly during a normal operating mode and a cylinder deactivation function, comprising: for normal operating mode: 1) Moving the first switchable castellation arrangement to the off position and the second switchable castellation arrangement to the on position and 2) rotating the base body by a predetermined distance sufficient to actuate the second valve via the second switchable castellation arrangement for the normal operating mode, wherein the first switchable castellation arrangement experiences a lost motion and the movement is not transmitted to the first valve via the first switchable castellation arrangement, and for the cylinder deactivation function: 1) moving the first switchable castellation assembly to the deactivated position and the second switchable castellation assembly to the deactivated position; and 2) Rotating the base body by the predetermined distance sufficient to actuate the second valve via the second switchable castellation arrangement for the normal operating mode, wherein the first valve experiences a lost motion via the first switchable castellation arrangement and the second valve experiences a lost motion via the second switchable castellation arrangement. [17] The method of claim 16, wherein the first switchable castellation arrangement and the second switchable castellation arrangement each comprise: a lost motion shaft, the lost motion shaft being adapted to transmit a lift profile to a valve end; and a switchable castellation device, the switchable castellation device comprising: a rotatable first keyway bushing, and a keyway body, wherein the first spline bushing is configured to switch between a locking position and an unlocking position, and wherein a lost motion is obtained by sliding the lost motion shaft when the first spline bushing is in the unlocking position. [18] The method of claim 17, wherein the rotatable first spline bushing of the first switchable castellation assembly has a height equal to a sum of a distance required for backlash of the first valve during the engine braking backlash function and a distance required for backlash of the first valve during the cylinder deactivation function. [19] A method according to claim 17 or claim 18, wherein the rotatable first spline sleeve of the second switchable castellation arrangement has a height equal to a sum of a distance required for lost motion of the second valve during the cylinder deactivation function of the second valve. [20] A method according to any one of claims 17 to 19, wherein the collapse of the second switchable castellation arrangement during the engine braking lost motion function is achieved by offsetting a lower surface of the first keyway bushing from an upper surface of the keyway body by a predetermined distance.

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