Rocker arm assembly with roller deactivation

Abstract

A variable valve lift rocker arm assembly may include an outer rocker arm body having a valve end and a cam end. The outer rocker arm body may be configured to rotate around a first axle of the outer rocker arm body. The variable valve lift rocker arm assembly may include an inner rocker arm body configured to selectively and operatively latch to the outer rocker arm body through a latching assembly. The latching assembly may include one or more latch pins actuated by a first actuating assembly and a second actuating assembly to switch between a latched mode and an unlatched mode. In the latched mode, the relative motion between the inner rocker arm body and the outer rocker arm body may be locked. In the unlatched mode, the relative motion between the inner rocker arm body and the outer rocker arm body may be permitted.

Description

ATTORNEY DOCKET PATENT APPLICATION 006976.2304 1 of 36 ROCKER ARM ASSEMBLY WITH ROLLER DEACTIVATION FIELD

[0001] This application relates to rocker arm assemblies and, more particularly, to variable valve lift rocker arm assemblies with a switchable roller for use in, for example, a valve train of an internal combustion engine, allowing the use of deactivation and other variable valve actuation techniques. BACKGROUND

[0002] An internal combustion engine can include a valve train assembly. A valve train assembly includes rocker arms for controlling the opening and closing of intake and exhaust valves. A rocker arm is a reciprocating lever that translates radial motion of a rotating camshaft lobe into linear motion that controls the opening and closing of a valve. The rocker arm is mounted on a rocker shaft with one end in direct or indirect contact with a rotating camshaft lobe and the other end being structurally interfaced with a valve.

[0003] Variable valve actuation mechanisms, such as cylinder deactivation and variable valve lift, have been introduced to improve engine performance, fuel economy, and / or emissions of an internal combustion engine. To support a variable valve actuation mechanism, a switchable rocker arm may be used. SUMMARY

[0004] In particular embodiments, a variable valve lift rocker arm assembly may include an outer rocker arm body comprising a valve end and a cam end. The outer rocker arm body may be configured to rotate around a first axle of the outer rocker arm body. The variable valve lift rocker arm assembly may include an inner rocker arm body configured to selectively and operatively latch to the outer rocker arm body through a latching assembly. The latching assembly may comprise one or more latch pins actuated by a first actuating assembly and a second actuating assembly to switch between a latched mode and an unlatched mode. In the latched mode, relative motion between the inner rocker arm body and the outer rocker arm body may be locked. In the unlatched mode, the relative motion between the inner rocker arm body and the outer rocker arm body is permitted. ACTIVE 512643856.1ATTORNEY DOCKET PATENT APPLICATION 006976.2304 2 of 36

[0005] In particular embodiments, a variable valve lift rocker arm assembly may include an outer rocker arm body comprising a valve end and a cam end. The outer rocker arm body may be configured to rotate around a first axle of the outer rocker arm body, and the cam end comprises a first bore. An inner rocker arm body may be coupled to the outer rocker arm body and configured to pivot around the first axle or a second axle. The inner rocker arm body may comprise a second bore and an interface for engaging a cam. A latching assembly may be disposed within the first bore and the second bore. The latching assembly may comprise one or more latch pins, a first actuation mechanism configured to exert a first force to push the one or more latch pins in a first direction to a latched position, at which the one or more latch pins prevent relative motion between the inner rocker arm body and the outer rocker arm body, and a second actuation mechanism configured to exert a second force push the one or more latch pins in a second direction opposite to the first direction to an unlatched position, at which the latching assembly allows relative motion between the inner rocker arm body and the outer rocker arm body.

[0006] In particular embodiments, a variable valve lift rocker arm assembly may comprise an outer rocker arm body comprising a valve end and a cam end. The variable valve lift rocker arm assembly may comprise an outer rocker arm body configured to rotate around a first axle of the outer rocker arm body. The variable valve lift rocker arm assembly may comprise an inner rocker arm body configured to (1) rotate around the first axle or a second axle of the outer rocker arm body and (2) selectively and operatively latch to the outer rocker arm body through a latching assembly. The latching assembly may comprise a first latch pin actuated by a latch pin spring, a second latch pin, and a third latch pin driven by a hydraulic, mechanical or pneumatic force. The latching assembly may be configured to have a latched mode in which the inner rocker arm body and the outer rocker arm body move as a unitary body. The latching assembly may be configured to have an unlatched mode in which the inner rocker arm body is permitted to rotate around the second axle while the outer rocker arm body rotates around the first axle.

[0007] The clauses below summarize various embodiments described herein.

[0008] Clause 1. A variable valve lift rocker arm assembly comprising: an outer rocker arm body comprising a valve end and a cam end, wherein the outer rocker arm body is configured to rotate around a first axle of the outer rocker arm body; and an inner rocker arm body configured to selectively and operatively latch to the outer rocker arm body through a ACTIVE 512643856.1ATTORNEY DOCKET PATENT APPLICATION 006976.2304 3 of 36 latching assembly, wherein: the latching assembly comprises one or more latch pins actuated by a first actuating assembly and a second actuating assembly to switch between a latched mode and an unlatched mode, wherein; in the latched mode, relative motion between the inner rocker arm body and the outer rocker arm body is locked; and in the unlatched mode, the relative motion between the inner rocker arm body and the outer rocker arm body is permitted.

[0009] Clause 2. The variable valve lift rocker arm assembly of any one of the preceding Clauses, wherein the inner rocker arm body is configured to rotate around the first axle with the outer rocker arm body in the latched mode.

[0010] Clause 3. The variable valve lift rocker arm assembly of any one of the preceding Clauses, wherein the inner rocker arm body is configured to rotate around a second axle of the outer rocker arm body in the unlatched mode.

[0011] Clause 4. The variable valve lift rocker arm assembly of any one of the preceding Clauses, wherein the first actuating assembly exerts a first force pushing the one or more latch pins toward a first direction, and wherein the second actuating assembly exerts a second force pushing the one or more latch pins toward a second direction which is opposite to the first direction.

[0012] Clause 5. The variable valve lift rocker arm assembly of any one of the preceding Clauses, wherein the one or more latch pins comprises a first latch pin, a second latch pin, and a third latch pin, wherein the first actuating assembly comprises a latch pin spring, and wherein the second actuating assembly comprises a hydraulic, mechanical or pneumatic device.

[0013] Clause 6. The variable valve lift rocker arm assembly of any one of the preceding Clauses, wherein the cam end comprises a first bore configured to seat (1) a first latch receiving structure configured to receive the first latch pin, and (2) a second latch receiving structure configured to receive the third latch pin, and wherein the first latch pin has a length equals to an inner length of the first latch receiving structure.

[0014] Clause 7. The variable valve lift rocker arm assembly of any one of the preceding Clauses, wherein the inner rocker arm body comprises a second bore configured to receive a shaft bushing, wherein a switchable roller is installed on external surface of the shaft bushing and is configured to engage with a cam, wherein the shaft bushing is configured to ACTIVE 512643856.1ATTORNEY DOCKET PATENT APPLICATION 006976.2304 4 of 36 receive the second latch pin within the shaft bushing, and wherein the second latch pin has a length equal to that of the shaft bushing.

[0015] Clause 8. The variable valve lift rocker arm assembly of any one of the preceding Clauses, wherein the switchable roller is configured to suppress a lost motion spring when the latching assembly is in the unlatched mode, and wherein the lost motion spring is configured to absorb cam force received by the switchable roller.

[0016] Clause 9. The variable valve lift rocker arm assembly of any one of the preceding Clauses, wherein the latching assembly is configured to be in the latched mode by default.

[0017] Clause 10. A variable valve lift rocker arm assembly comprising: an outer rocker arm body comprising a valve end and a cam end, wherein the outer rocker arm body is configured to rotate around a first axle of the outer rocker arm body, and the cam end comprises a first bore; an inner rocker arm body coupled to the outer rocker arm body and configured to pivot around the first axle or a second axle, wherein the inner rocker arm body comprises a second bore and an interface for engaging a cam; and a latching assembly disposed within the first bore and the second bore, wherein the latching assembly comprises: one or more latch pins; a first actuation mechanism configured to exert a first force to push the one or more latch pins in a first direction to a latched position, at which the one or more latch pins prevent relative motion between the inner rocker arm body and the outer rocker arm body; and a second actuation mechanism configured to exert a second force push the one or more latch pins in a second direction opposite to the first direction to an unlatched position, at which the latching assembly allows relative motion between the inner rocker arm body and the outer rocker arm body.

[0018] Clause 11. The variable valve lift rocker arm assembly of any one of the preceding Clauses, wherein the interface for engaging the cam comprises a switchable roller or a curved surface.

[0019] Clause 12. The variable valve lift rocker arm assembly of any one of the preceding Clauses, wherein the one or more latch pins comprises a first latch pin, a second latch pin, and a third latch pin, and wherein the first bore is configured to seat (1) a first latch receiving structure configured to receive the first latch pin, and (2) a second latch receiving structure configured to receive the third latch pin, and wherein the first latch pin has a length equals to an inner length of the first latch receiving structure. ACTIVE 512643856.1ATTORNEY DOCKET PATENT APPLICATION 006976.2304 5 of 36

[0020] Clause 13. The variable valve lift rocker arm assembly of any one of the preceding Clauses, wherein the second bore is configured to receive a shaft bushing, wherein a switchable roller is installed on external surface of the shaft bushing and is configured to engage with a cam, wherein the shaft bushing is configured to receive the second latch pin within the shaft bushing, and wherein the second latch pin has a length equal to that of the shaft bushing.

[0021] Clause 14. The variable valve lift rocker arm assembly of any one of the preceding Clauses, wherein the switchable roller is configured to suppress a lost motion spring when the one or more latch pins are at the unlatched position, and wherein the lost motion spring is configured to absorb cam force received by the switchable roller.

[0022] Clause 15. A variable valve lift rocker arm assembly comprising: an outer rocker arm body comprising a valve end and a cam end, wherein the outer rocker arm body is configured to rotate around a first axle of the outer rocker arm body; and an inner rocker arm body configured to (1) rotate around the first axle or a second axle of the outer rocker arm body and (2) selectively and operatively latch to the outer rocker arm body through a latching assembly, wherein: the latching assembly comprises a first latch pin actuated by a latch pin spring, a second latch pin, and a third latch pin driven by a hydraulic, mechanical or pneumatic force; the latching assembly is configured to have a latched mode in which the inner rocker arm body and the outer rocker arm body move as a unitary body; and the latching assembly is configured to have an unlatched mode in which the inner rocker arm body is permitted to rotate around the second axle while the outer rocker arm body rotates around the first axle.

[0023] Clause 16. The variable valve lift rocker arm assembly of any one of the preceding Clauses, wherein the cam end comprises a first bore configured to seat (1) a first latch receiving structure configured to receive the first latch pin, and (2) a second latch receiving structure configured to receive the third latch pin, and wherein the first latch pin has a length equals to an inner length of the first latch receiving structure.

[0024] Clause 17. The variable valve lift rocker arm assembly of any one of the preceding Clauses, wherein the inner rocker arm body comprises a second bore configured to receive a shaft bushing, wherein a switchable roller is installed on external surface of the shaft bushing and is configured to engage with a cam, wherein the shaft bushing is configured to receive the second latch pin within the shaft bushing, and wherein the second latch pin has a length equal to that of the shaft bushing. ACTIVE 512643856.1ATTORNEY DOCKET PATENT APPLICATION 006976.2304 6 of 36

[0025] Clause 18. The variable valve lift rocker arm assembly of any one of the preceding Clauses, wherein the switchable roller is configured to suppress a lost motion spring when the latching assembly is in the unlatched mode, and wherein the lost motion spring is configured to absorb cam force received by the switchable roller.

[0026] Clause 19. The variable valve lift rocker arm assembly of any one of the preceding Clauses, wherein the first latch pin, the second latch pin, and the third latch pin are configured to move between a latched position and an unlatch position as actuated by the latch pin spring and driven by the hydraulic, mechanical or pneumatic force.

[0027] Clause 20. The variable valve lift rocker arm assembly of any one of the preceding Clauses, wherein the inner rocker arm body is configured to rotate around the second axle when the latching assembly is in the unlatched mode, and wherein the inner rocker arm body is configured to rotate around the first axle when the latching assembly is in the latched mode. ACTIVE 512643856.1ATTORNEY DOCKET PATENT APPLICATION 006976.2304 7 of 36

[0029] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the claimed invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The present invention will be described in greater detail below based on the exemplary figures. However, it should be noted that the concepts contemplated herein are not limited to the exemplary embodiments. Other features and advantages of various embodiments of the present invention will become apparent by reading the following detailed description with reference to the figures.

[0031] FIG.1A illustrates a perspective view of a variable valve lift rocker arm assembly with roller deactivation for an internal combustion engine according to one embodiment of the present disclosure.

[0032] FIG.1B illustrates another perspective view of the variable valve lift rocker arm assembly with roller deactivation as shown in FIG.1A.

[0033] FIG. 1C illustrates a perspective view of a variable valve lift rocker arm assembly with roller deactivation.

[0034] FIG.2A illustrates a cut-away perspective view of the variable valve lift rocker arm assembly with roller deactivation, showing the lost motion spring assembly and the inner rocker arm body in a cam base circle position.

[0035] FIG.2B illustrates another cut-away perspective view of the variable valve lift rocker arm assembly with roller deactivation, showing the lost motion spring assembly and the inner rocker arm body in the cam base circle position.

[0036] FIG.2C illustrates another cut-away perspective view of the variable valve lift rocker arm assembly with roller deactivation, showing the lost motion spring assembly and the inner rocker arm body in the cam lift position.

[0037] FIG.3A illustrates a cut-away perspective view of the variable valve lift rocker arm assembly with roller deactivation, showing the inner structure of the latching axle assembly in a default latched mode with the roller in a cam base circle position.

[0038] FIG.3B illustrates a cut-away perspective view of the variable valve lift rocker arm assembly with roller deactivation, showing the inner structure of the latching axle assembly in an unlatched mode with the roller in a cam lift position. ACTIVE 512643856.1ATTORNEY DOCKET PATENT APPLICATION 006976.2304 8 of 36

[0039] FIG.4A illustrates a cut-away perspective view of the variable valve lift rocker arm assembly with roller deactivation, showing the inner structure of the latching axle assembly in a default unlatched mode.

[0040] FIG.4B illustrates a cut-away perspective view of the variable valve lift rocker arm assembly with roller deactivation, showing the inner structure of the latching axle assembly in a latched mode.

[0041] FIG.5A illustrates a plot of valve lift over the cam angle for the latch assembly in the unlatched mode.

[0042] FIG. 5B illustrates a plot of valve lift over the cam angle for the latch assembly in the latched mode.

[0043] FIG. 6 illustrates a perspective view of a variable valve lift rocker arm assembly with roller deactivation wherein two rollers can be deactivated. DETAILED DESCRIPTION

[0044] FIG.1A illustrates a perspective view 100A of a variable valve lift rocker arm assembly 10 with roller deactivation for an internal combustion engine according to one embodiment of the present disclosure. FIG. 1B illustrates another perspective view 100B of the variable valve lift rocker arm assembly 10 with roller deactivation as shown in FIG. 1A. Rocker arm assembly 10 may be configured to support various variable valve actuation mechanisms in internal combustion engines. Further, while the disclosed embodiment may be beneficial for enabling variable valve lift on type III (center pivot) valve trains, the systems, devices, and processes in the present disclosure may be applied to, or used in connection with, many other types of valve train systems and configurations comprising one or more cam- actuated rollers. Similarly, while the disclosed embodiments may be beneficial to heavy duty vehicles and machines, the systems, devices, and processes in the present disclosure may be applied to, or used in connection with, many other types of vehicles and applications.

[0045] As shown in FIGs. 1A and 1B, in particular embodiments, the outer rocker arm body 103 may have at least one valve end. For example, the outer rocker arm body illustrated in FIGs. 1A and 1B may have two valve ends: the first valve end 101 and second valve end 102 on the valve side of outer rocker arm body 103. As shown in FIGs.1A and 1B, the first valve end 101 and second valve end 102 may include a bore hole through which a threaded rod is coupled and is secured by a nut. An elephant foot may be coupled to threaded ACTIVE 512643856.1ATTORNEY DOCKET PATENT APPLICATION 006976.2304 9 of 36 rod for interfacing directly or indirectly with a valve stem or other structure associated with a valve. The bore holes of the first valve end 101 and the second valve end 102 may accommodate other components in lieu of, or in addition to, the threaded rod, the nut, and the elephant foot, including, for example, a spigot, a lash adjuster, an actuatable capsule, or a piston, among other options that can be a component in the bores. In particular embodiments, the inner rocker arm body 112 may be an interface between the second roller 115 and the outer rocker arm body 103. The inner rocker arm body 112 may have a bore 109 configured to receive a latching axle assembly 12 to be further discussed below. The inner rocker arm body 112 may have a suitable shape to receive second roller 115.

[0046] In particular embodiments, the outer rocker arm body 103 may comprise a number of cam ends including, for example, but not limited to, a first cam end 105, a second cam end 107, and a third cam end 108. The variable valve lift rocker arm assembly 10 may include a main roller 106, and an inner rocker arm body 112 which receives a second roller 115 (as shown in FIGs.1A, 1B) inside the inner rocker arm body 112. The main roller 106 may be a fixed roller and the second roller 115 may be a deactivating roller, or in other words, it is a switchable roller that can be activated or deactivated through the operation of the latching axle assembly, as will be further discussed below.

[0047] In particular embodiments, the latching axle assembly 12 may be installed in a bore 109 that extends through the first cam end 105, the second cam end 107, and the third cam end 108 of the outer rocker arm body 103, as well as the inner rocker arm body 112, the main roller 106, and second roller 115. The bore 109 may be configured to receive latching axle assembly 12. In particular embodiments, the bore 109 may include two sections (as shown in FIGs.3A and 3B) with different radii. The first section of the bore 109 may receive a shaft on which the main roller 106 is installed and the second section of the bore 109 may receive the latching axle assembly 12. The first section of the bore 109 may have a slightly larger radius than the second section and the two sections may share the same center axle. The latching axle assembly 12, which comprises at least one latching mechanism including a number of latch pins, as will be discussed further below.

[0048] In particular embodiments, referring to FIGs.1A-1B, FIGs.2A-2C, and FIGs. 3A-3B, the variable valve lift rocker arm assembly 10 may include an outer rocker arm body 103 and an inner rocker arm body 112. The inner rocker arm body 112 may be coupled with the lost motion spring assembly 11 and may receive the second roller 115 which is a switchable ACTIVE 512643856.1ATTORNEY DOCKET PATENT APPLICATION 006976.2304 10 of 36 roller as controlled by the latching axle assembly 12. The most motion spring assembly 11 may include the lost motion spring (LMS) 111 and the LMS retainer inside the LMS 111. The LMS retainer may have a first end connected to the valve end 101 and a second end connected to the inner rocker arm body 112 through the retain latch pin 119.

[0049] The inner rocker arm body 112 may be within the gap between the second cam end 107 and the third cam end 108. The inner rocker arm body 112 may be coupled to a shaft bushing 126 which has an inner bore to receive the second latch pin 123 but allow the second patch pin 123 to move within the inner bore. When the inner rocker arm body 112 is in a cam base circle position, the second latch pin 123 may be aligned with the first latch pin 122 and the third latch pin 124, along their shared center axle line and the three latch pins (122, 123, and 124) may move along their shared center axle line when actuated by the latch pin spring 111 and the control oil in the pressurized chamber 127. The first latch pin 122 may have a cavity for receiving the latch ping spring 121.

[0050] When the latching axle assembly 12 is in the latched mode, the inner rocker arm body 112 may be mechanically latched to the outer rocker arm body 103 and may transfer any cam force received by the second roller 115 to the valve end of the outer rocker arm body 103. When the latching axle assembly 12 is in the unlatched mode, the inner rocker arm body 112 may be mechanically unlatched from the outer rocker arm body 103 and may rotate around the pivot axle 114 against the lost motion spring force of the lost motion spring 111. As a result, the cam force from the cam interfacing with the second roller 115 may be totally or partially absorbed by the lost motion spring 111.

[0051] Because the motion of the inner rocker arm body 112 compresses the lost motion spring 111, some of the force from the camshaft lobe and a portion of the resulting motion may be absorbed by the lost motion spring 111. If the lost motion spring 111 absorbs all of the force from the interfacing cam, the second roller 115 may be considered completely deactivated. But it is also possible for a portion of the force from the camshaft lobe motion to be conveyed to valve end for a partially deactivated variable valve lift function. Note that main roller 106 may remain fixed with respect to the outer rocker arm body 103, even while the second roller 115 is movable with respect to the outer rocker arm body 103. When the cam interfacing with the second roller 115 returns to a cam base circle position, the force from the camshaft lobe may subside and the lost motion spring 111 may drive the inner rocker arm body 112 and the second roller 115 back to the cam base circle position. ACTIVE 512643856.1ATTORNEY DOCKET PATENT APPLICATION 006976.2304 11 of 36

[0052] In particular embodiments, the lost motion spring assembly 11 may include a lost motion spring (LMS) 111 which is coupled to a lost motion spring retainer inside the lost motion spring 111. The LMS retainer may have a first retainer end connected to the valve end 101 and a second retainer end connected to the inner rocker arm body 112 through the retainer latch pin 119. In particular embodiments, the retainer latch pin 119 on the second end of the retainer may be configured to rest on a hard stop structure 113 which is a part of the outer rocker arm body 103. The hard stop structure 113 for the LMS assembly 11 may mechanically provide a stop position for the LMS 111 when the LMS pushes the inner rocker arm body 112 back to the cam base circle position, and may cause the latching components of the latching axle assembly 12 (including the three latch pins 122, 123, 124) to be aligned to each other along the their shared center line when the retainer latch pin 119 rests on the top surface of the hardstop structure 113. In particular embodiments, this LMS assembly 11 integrating the hard stopstructure 113 may enable a smoother switching process between the latched and unlatched modes and an easier valve lash adjustment process.

[0053] In particular embodiments, the outer rocker arm body 103 may have an outer shaft bore 104 which is configured to receive a rocker shaft (not shown) around which the outer rocker arm body 103 may rotate. In particular embodiments, the rocker shaft (not shown) in the outer shaft bore 104 may include fluid galleries for supplying lubrication fluid and / or control oil to one or both of the first and second valve ends 101, 102 and one or more actuation ports (128A and 128B in FIG.3B; 148A and 148B in FIG.4B) for actuating latch pins (124 in FIGs.3A and 3B and 144 in FIGs.4A and 4B). The actuation ports may provide a path for the control oil to enter the pressurized oil chamber 127, which is the between the third latch pin 124 and the end wall of the second latch receiving structure 129. The control oil in the pressurized oil chamber 127 may provide force to actuate the latch pins (e.g., 122, 123, and 124) causing the latch pins to switch between the latched and unlatched positions. The fluid galleries may provide control oil to the first and second actuation ports (128A and 128B in FIG.3B; 148A and 148B in FIG.4B) from the outer shaft bores. Fluid pathways may likewise be formed from outer shaft bore to valve ends, among other options.

[0054] FIG.1C illustrates a perspective view 100C of a variable valve lift rocker arm assembly 13 with roller deactivation capability. In particular embodiments, the rocker arm assembly 13 may be configured to support various variable valve actuation mechanisms in internal combustion engines. Further, while the disclosed embodiment may be beneficial for ACTIVE 512643856.1ATTORNEY DOCKET PATENT APPLICATION 006976.2304 12 of 36 enabling variable valve lift on type III (center pivot) valve trains, the systems, methods, and processes in the present disclosure may be applied to, or used in connection with, many other types of valve train systems and configurations comprising one or more cam-actuated rollers. Similarly, while the disclosed embodiment may be beneficial to heavy duty vehicles and machines, the systems, methods, and processes in the present disclosure may be applied to, or used in connection with, many other types of vehicles and applications.

[0055] As shown in FIG. 1C, the valve end 181 may include a bore hole through which a threaded rod is coupled and is secured by a nut. An elephant foot may be coupled to threaded rod for interfacing directly or indirectly with a valve stem or other structure associated with a valve. The bore hole of the valve end 181 may accommodate other components in lieu of, or in addition to, the threaded rod, the nut, and the elephant foot, which includes, for example, a spigot, a lash adjuster, an actuatable capsule, or a piston, among other options that may be a component in the bores. The single valve end 181 may be used to control one or more valves (e.g., through a bridge structure).

[0056] In particular embodiments, the outer rocker arm body 103 may comprise a number of cam ends including, for example, but not limited to, a first cam end 105, a second cam end 107, and a third cam end 108. The variable valve lift rocker arm assembly 13 may include a main roller 106, and an inner rocker arm body 112 which receives a second roller 115 inside the inner rocker arm body 112. The main roller 106 may be a fixed roller and the second roller 115 may be a deactivating roller, or in other words, it may be a switchable roller that may be activated or deactivated through the operation of the latching axle assembly 12, as will be discussed in detail below.

[0057] In particular embodiments, the latching axle assembly 12 may be installed in a bore 109 that extends through the first cam end 105, the second cam end 107, and the third cam end 108 of the outer rocker arm body 103, as well as inner rocker arm body 112, the main roller 106, and second roller 115. The bore 109 may be configured to receive latching axle assembly 12. In particular embodiments, the bore 109 may include two sections (as shown in FIGs.3A-3B and 4a-4B) with different radius. The first section of the bore 109 may receive a shaft on which the main roller 106 is installed and the second section of the bore 109 may receive the latching axle assembly 12. The first section of the bore 109 may have a slightly larger radius than the second section and the two sections may share the same center axle. The latching axle assembly 12, which comprises at least one latching mechanism including a ACTIVE 512643856.1ATTORNEY DOCKET PATENT APPLICATION 006976.2304 13 of 36 number of latch pins (e.g., 122, 123, 124 in FIGs. 3A and 3B), as will be discussed further below.

[0058] In particular embodiments, referring to FIG.1C and FIGs.2A-2B and 3A-3B, the variable valve lift rocker arm assembly 13 may include an outer rocker arm body 103 and an inner rocker arm body 112. The inner rocker arm body 112 may be coupled with the lost motion spring assembly 11 and may receive the second roller 115 which is a switchable roller as controlled by the latching axle assembly 12. The most motion spring assembly 11 may include the lost motion spring (LMS) 111 and the LMS retainer inside the LMS 111. The LMS retainer may have a first end connected to the valve end 181 and a second end connected to the inner rocker arm body 112 through the retain latch pin 119.

[0059] Referring to FIG.1C and FIGs.2A-2B and 3A-3B, the inner rocker arm body 112 may be within the gap between the second cam end 107 and the third cam end 108. The inner rocker arm body 112 may be coupled to a shaft bushing 126 which has an inner bore to receive the second latch pin 123 but allow the second patch pin 123 to move within the inner bore. When the inner rocker arm body 112 is in a cam base circle position, the second latch pin 123 may be aligned with the first latch pin 122 and the third latch pin 124 along their shared center axle line and the three latch pins (122, 123, and 124) may move along their shared center axle line when actuated by the latch pin spring 111 and / or the control oil in the pressurized chamber 127. The first latch pin 122 may have a cavity for receiving the latch pin spring 121.

[0060] When the latching axle assembly 12 is in the latched mode, the inner rocker arm body 112 may be mechanically latched to the outer rocker arm body 103 and may transfer any cam force received by the second roller 115 to the valve end 181 of the outer rocker arm body 103. When the latching axle assembly 12 is in the unlatched mode, the inner rocker arm body 112 may be mechanically unlatched from the outer rocker arm body 103 and may be permitted to rotate around the pivot axle 114 against the lost motion spring force of the lost motion spring 111. As a result, the cam force from the cam interfacing with the second roller 115 may be totally or partially absorbed by the lost motion spring 111.

[0061] Because the motion of the inner rocker arm body 112 compresses the lost motion spring 111, some of the force from the camshaft lobe and a portion of the resulting motion may be absorbed by the lost motion spring 111. If the lost motion spring 111 absorbs all or most of the force from the interfacing cam, the second roller 115 may be considered completely deactivated. But it is also possible for a portion of the force from the camshaft lobe ACTIVE 512643856.1ATTORNEY DOCKET PATENT APPLICATION 006976.2304 14 of 36 motion to be conveyed to valve end for a partially deactivated variable valve lift function. Note that main roller 106 may remain fixed with respect to outer rocker arm body 103, even while the second roller 115 is movable with respect to outer body. When the cam interfacing with the second roller 115 returns to a cam base circle position, the force from the camshaft lobe may subside and the lost motion spring 111 may drive the inner rocker arm body 112 and the second roller 115 back to the cam base circle position.

[0062] In particular embodiments, the lost motion spring assembly 11 may include a lost motion spring (LMS) 111 which is coupled to a lost motion spring retainer inside the lost motion spring 111. The LMS retainer may have a first retainer end connected to the valve end 181 and a second retainer end connected to the inner rocker arm body 112 through the retainer latch pin 119. In particular embodiments, the retainer latch pin 119 on the second end of the retainer may be configured to rest on a hard stop structure 113 which is a part of the outer rocker arm body 103. The hard stop structure 113 for the LMS assembly 11 may mechanically provide a stop position for the LMS 111 when the LMS pushes the inner rocker arm body 112 back to the cam base circle position, and may cause the latching components of the latching axle assembly 12 (including the three latch pins 122, 123, 124) to be aligned to each other along the their shared center line when the retainer latch pin 119 rests on the top surface of the hard stop structure 113. In particular embodiments, this lost motion assembly integrating the hard stop structure 113 may enable a smoother switching process between the latched and unlatched modes and an easier valve lash adjustment process.

[0063] In particular embodiments, the outer rocker arm body 103 may have an outer shaft bore 104 which is configured to receive a rocker shaft (not shown) around which the outer rocker arm body 103 may rotate. In particular embodiments, the rocker shaft (not shown) in the outer shaft bore 104 may include fluid galleries for supplying lubrication fluid and / or control oil to one or the valve end 181 and one or more actuation ports (128A and 128B in FIG. 3B; 148A and 148B in FIG. 4B) for actuating latch pins (124 in FIGs. 3A and 3B and 144 in FIGs.4A and 4B). The actuation ports may provide a path for the control oil to enter the pressurized oil chamber (e.g., 127 in FIGs.3A and 3B, 147 in FIGs. 4A and 4B) which is the between the third latch pin (e.g., 124, 144) and the wall of the second latch receiving structure (e.g., 129, 149). The control oil in the pressurized oil chamber (e.g., 127, 147) may provide force to actuate the latch pins (e.g., 122, 123, and 124) causing the latch pins to switch between the latched and unlatched positions. The fluid galleries may provide control oil to the first and ACTIVE 512643856.1ATTORNEY DOCKET PATENT APPLICATION 006976.2304 15 of 36 second actuation ports (128A and 128B in FIG.3B; 148A and 148B in FIG.4B) from the outer shaft bores. Fluid pathways may likewise be formed from outer shaft bore to valve ends, among other options.

[0064] Referring to FIG. 1C, the inner rocker arm body 112 may be an interface between the second roller 115 and the outer rocker arm body 103. The inner rocker arm body 112 may have a bore 109 configured to receive a latching axle assembly 12 to be discussed below. The inner rocker arm body 112 may have a suitable shape to receive second roller 115. The outer rocker arm body 103 may have one valve end 181. The main roller 106 may be configured to interface with a first cam 171 installed on a camshaft. The second roller 115 may be configured to interface with a second cam 172 installed on the same camshaft on which the first cam 171 is installed.

[0065] The first cam 171 and the second cam 172 may have different cam lobe shapes, resulting in two different cam profiles. As discussed above, the second roller 115 may be completely or partially deactivated by the latching axle assembly 12. When the second roller 115 is completely deactivated by unlatching the latch pins in the latching axle assembly 12, the inner rocker arm body 112 may freely rotate around the pivot axle 114 as actuated by the cam 172, with respect to other portions of the rocker arm assembly 13. As a result, the rotation force from the cam 172 may not be transferred to the outer rocker arm body 103 and the motion of the outer rocker arm body 103 may follow the cam profile of the cam 171 only. In contrast, when the second roller 115 is activated by latching the latch pins in the latching axle assembly 12, the inner rocker arm body 112 may be mechanically latched and thus fixed to the outer rocker arm body 103 and other portions of the rocker arm assembly 13. As a result, the rotation force from the cam 172 may be fully transferred to the outer rocker arm body 103 and the valve end of the rocker arm assembly 13, causing the motion of the outer rocker arm body 103 to follow the cam profile of the combination of cam 172 and cam 171. In other words, in the latched mode, the inner rocker arm body 112 and the outer rocker arm body 103 may move together as a unitary body and may rotate around the shaft (not shown) seated in the shaft bore 104.

[0066] When the second roller 115 is partially deactivated, the outer rocker arm body 103 may transfer the lift force from the first cam 171 interfacing with the main roller 106 and at least a portion of the lift force from the second cam 172 interfacing with the second roller 115 to the valve end. The cam force from the first cam 171 that interfaces with the main roller ACTIVE 512643856.1ATTORNEY DOCKET PATENT APPLICATION 006976.2304 16 of 36 106 and from the second cam 172 that interfaces with the second roller 115 may combined and transferred to the valve end of the rocker arm assembly causing the rocker arm to follow a combined profile of the first cam 171 and partial profile of second cam 172 which is not absorbed by lost motion spring (LMS) 111.

[0067] FIG.2A is a cut-away perspective view 200A of the variable valve lift rocker arm assembly 10 with roller deactivation, showing the lost motion spring assembly 11 and the inner rocker arm body 112 in a cam base circle position. FIG.2B illustrates another cut-away perspective view 200B of the variable valve lift rocker arm assembly 13 with roller deactivation, showing the lost motion spring assembly 11 and the inner rocker arm body 112 in the cam base circle position. As shown in FIGs.2A and 2B, in the cam base circle position, the lost motion spring 111 may be in an extended state and not suppressed by rotation of the inner rocker arm body 112 which can be actuated by the cam force. The lost motion spring assembly 11 may be in its initial state and the inner rocker arm body 112 may be at its initial position (not rotated around the pivot axle 114).

[0068] FIG. 2C illustrates another cut-away perspective view 200C of the variable valve lift rocker arm assembly 13 with roller deactivation, showing the lost motion spring assembly 11 and the inner rocker arm body 112 in the cam lift position. As discussed above, when the latching mechanism of the latching axle assembly 12 is unlatched, the inner rocker arm body 112 may be free to rotate around the pivot axle 114 with respect to the outer rocker arm body 103, when the second roller 115 is pushed by the cam force. The inner rocker arm body 112 may transfer the cam force from the cam to a rotational force around the pivot axle 114 and apply a suppressing force to the lost motion spring 111. As a result, the lost motion spring 111 may be suppressed. It is notable that, in this embodiment, in the unlatched mode, the inner rocker arm body 112 may rotate around the pivot axle 114, which is different from the center line of the shaft bushing seated in the outer shaft bore 104. The pivot axle 114 may be implemented as a separate axle (e.g., similar to the pivot axle 145 in FIG.4A and 4B) rather than using the shaft bushing seated in the outer shaft bore 104. In the deactivation mode, the inner rocker arm body 112 may rotate around the pivot axle 114 (or the pivot axle 145 in FIG. 4A and 4B) rather than using the rockshaft bushing in the outer shaft bore 104 as the pivot axle. In particular embodiments, the pivot axle 114 may be parallel to the center line of the shaft bushing seated in the outer shaft bore 104. ACTIVE 512643856.1ATTORNEY DOCKET PATENT APPLICATION 006976.2304 17 of 36

[0069] FIG. 3A illustrates a cut-away perspective view 300A of the variable valve lift rocker arm assembly 13 with roller deactivation, showing the inner structure of the latching axle assembly 12 in a default latched mode with the second roller 115 in a cam base circle position. As discussed above, the latching axle assembly 12 may have a latching mechanism including a latch pin spring 121, a first latch pin 122, a second latch pin 123, and a third latch pin 124. The three latch pins 122, 123, and 124 may be arranged within latch pin latch receiving structures including a first latch receiving structure 138, a second latch receiving structure 129, and a shaft bushing 126. The first latch receiving structure 138 and the second latch receiving structure 129 may be seated in the bore 109 of the outer rocker arm body 103 that extends through the first cam end 105, the second cam end 107, and the third cam end 108 of the outer rocker arm body 103. The shaft bushing 126, which is seated in the inner bore of the inner rocker arm body 112, may have a width that is substantially equal to the length of the second latch pin 123 so that their ends may be aligned in the unlatched mode to allow the second roller 115 to rotate with respect to the outer arm body 103 in the deactivation mode. The second roller 115, which is a switchable roller, may be installed on the shaft bushing 126.

[0070] In this embodiment, the latching axle assembly 12 may be latched in a normal or default mode when the oil control valve (OCV) (not shown) is off, and the control oil is not pumped into the pressurized oil chamber 127 of the latching axle assembly 12. For example, in a default or normal mode, the latching axle assembly 12 may be in the latched mode as shown in FIG.3A, where the OCV is off, and the control oil is not pumped into the pressurized oil chamber 127 between the third latch pin 124 and the inner wall of the second latch receiving structure 129. When there is substantially no pressured oil in the chamber 127, per preset spring force of the latch pin spring 121 (also referred to as “bias spring”), the latching pin spring 121 may push the first latch pin 122, the second latch pin 123, and the third latch pin 124 to the other end of the latching axle assembly 12 where the second latch receiving structure 129 is located, until the third latch pin 124 hits the hard stop position by touching the end wall of the second latch receiving structure 129, latching the second rocker 115 to the out rocker body 103. In the latched mode, the first latch pin 122 and the second latch pin 123 may latch the inner and outer rocker arm bodies together, causing the cam force applied on the second roller 115 attached to the inner rocker arm body 112 to be transferred to the outer rocker arm body 103 and the valve end of the rocker arm assembly 13. As a result, the rocker arm assembly 13 may transfer the lift combination of the lifts from the first cam 171 interfacing with the main roller ACTIVE 512643856.1ATTORNEY DOCKET PATENT APPLICATION 006976.2304 18 of 36 106 and the second cam 172 interfacing with the second roller 115 to the valve end of the rocker arm assembly 13. In the latched mode, the cam force from the first cam 171 that interfaces with the main roller 106 and from the second cam 172 that interfaces with the second roller 115 may be transferred to the valve end of the rocker arm assembly causing the rocker arm motion to follow a profile combination of both cam profiles of the first and second cams (171, 172).

[0071] The third latch pin 124 may have a protrusion on its end configured to touch the end wall of the second latch receiving structure 129 and to leave a space in the pressurized oil chamber 127 between the main end surface of the third latching pin 124 and the end wall of the second latch receiving structure 129. In particular embodiments, the normally latched design may be applied for nature gas engine LIVC (late intake-vale closing) applications (e.g., with LIVC lift for best gas consumption economy, activated with normal lift for better acceleration and automatic transmission shifting strategy).

[0072] FIG.3B illustrates a cut-away perspective view 300B of the variable valve lift rocker arm assembly 13 with roller deactivation, showing the inner structure of the latching axle assembly 12 in an unlatched mode with the roller in a cam lift position. The pressurized oil chamber 127 may be configured to hold the control oil. When the OCV is ON, the control oil may be pumped into the pressurized oil chamber 127 to push the latch pins 121, 123, and 124 to the end where the latch pin spring 121 is located to reach the unlatched position. The first latch pin 121 may have a cavity for receiving the latch pin spring 111. The third latch pin 124 may serve as a piston to be pushed by the control oil in the pressurized oil chamber 127 and to push the other two latch pins 123 and 122 to the end where the latch pin spring 121 is located. The force on the third latch pin 124 received from the control oil may overcome the force of the latch pin spring 121 to push the other two latch pins 123 and 122 to the end where the latch pin spring 121 is located. The first latch pin 122 may be pushed to a hard stop position against the latch pin spring force by touching the end wall of the first latch receiving structure 138. The first latch pin 121 may have a length substantially equal to the inner length of the first latch receiving structure 138. The inner length of the first receiving structure 128 may refer to the distance between the inner end wall of a first end of the first receiving structure 128 and the other end that faces the shaft bushing 126 of the inner rocker arm body 112. As a result, the second latch pin 123 may be aligned to the shaft bushing 126 on which the second roller 115 is installed, causing the latching axle assembly 12 to be unlatched. In contrast, the third ACTIVE 512643856.1ATTORNEY DOCKET PATENT APPLICATION 006976.2304 19 of 36 latch pin 124 may have a length that is shorter than the inner length of the second latch receiving structure 129 so that when the three latch pins 122, 123, and 124 are pushed to the end of the second latch receiving structure 129, the second latch pin 123 is not aligned to the shaft bushing 126, causing the latching axle assembly 12 to be in latched mode.

[0073] When the second latch pin 123 is aligned with the shaft bushing 126, the second roller 115 may be deactivated. The inner rocker arm body 112 may be free to move with respect to the outer rocker arm body 103 by rotating around the pivot axle (114 in FIGs. 2A and 2B) against the spring force of the lost motion spring 111, as actuated by the cam interfacing with the second roller 115. The second roller 115, which is installed on the shaft bushing 126, may receive the cam force from the cam (e.g., 172 in FIG. 1C) that interfaces with the second roller 115. When the cam that interfaces with the second roller 115 exerts an upward cam force, the inner rocker arm body 112, the second latch pin 123, the shaft bushing 126, and the second roller 115 may be pushed upward by the cam force. As a result of the upward force, the lost motion spring assembly 11 may rotate around the pivot axle (114 in FIGs.2A and 2B) and the lost motion spring 111 may be suppressed. As a result of motion of the inner rocker arm body 112 and the suppression of the lost motion spring 111, the cam force from the cam that interfaces with the second roller 115 may be absorbed by the lost motion spring and not transferred to the outer rocker arm body 103 of the rocker arm assembly 13. Thus, the outer rocker arm body 103 may not follow the cam profile of the cam that interfaces with the second roller 115. The cam lift from the camshaft lobe that interfaces with the second roller 115 may be therefore absorbed by the lost motion spring and the rocker arm assembly 13 may realize or receive the transfer lift only from the other cam that interfaces with the main roller 106.

[0074] Referring to FIGs.1 and 3B, to switch from the unlatched mode to the latched mode, the OCV may be turned off, causing the control oil in the pressurized oil chamber 127 to be pushed out of the pressurized oil chamber 127 by the latch pin spring 121. When the second roller 115 does not receive the upward pushing force from the cam that interfaces with the second roller 115 (because the cam has rotated to a position that its short cam end faces the second roller 115), the lost motion spring 111 may push back the inner rocker arm body 112 to rotate around the pivot axle until the retainer latch pin (119 in FIG. 1C) is stopped by the top surface of the hard stop structure (113 in FIG.1C). As discussed above, the hard stop structure (113 in FIG.1C) may provide a hard stop position for the inner rocker arm body 112, causing ACTIVE 512643856.1ATTORNEY DOCKET PATENT APPLICATION 006976.2304 20 of 36 the second latch pin 123 to be at a position that is aligned with the first latch pin 121 and the third lath pin 124 along the shared center axle (and therefore getting the latch pins 122, 123, and 124 ready for moving along their shared axle as actuated by the spring force of the latch pin spring 121 to switch to latched mode). Because the control oil in the pressured oil chamber 127 has been pumped out and the chamber 27 has lost its high pressure, the latch pin string 121 may push the first latch pin 121, the second latch pin 123, and the third latch pin 124 (which are aligned along the shared center axle) to the other end of the latching axle assembly 12 where the second latch receiving structure 129 is located. As a result, the latching axle assembly 12 may be restored to the latched mode and latched by the first latch pin 122 and the second latch pin 124 as shown in FIG. 3A. The latched mode may allow the second roller 115 to receive cam force from the cam that interfaces with the second roller 115 and the received cam force may be transferred to the outer rocker arm body 103 of the rocker arm assembly 13 allowing the motion of the outer rocker arm body 103 and the valve end 181 to follow the cam profile of the cam that interfaces with the second roller 115.

[0075] FIG. 4A illustrates a cut-away perspective view 400A of a variable valve lift rocker arm assembly 16 with roller deactivation, showing the inner structure of the latching axle assembly 14 in a default unlatched mode. Similar to the embodiments as illustrated in FIGs. 3A and 3B and discussed above, the latching axle assembly 14 may have a latching mechanism including a latch pin spring 141, a first latch pin 142, a second latch pin 143, and a third latch pin 144. The first latch pin 142 may have a cavity for receiving the latch pin spring 141. The latch pins 142, 143, and 144 may be arranged within latch pin receiving structures including a first latch receiving structure 150, a second latch receiving structure 149, and a shaft bushing 146. The first latch receiving structure 150 and the second latch receiving structure 149 may be seated in the bore 139 that extends through the first cam end 155, the second cam end 156, and the third cam end 157 of the rocker arm assembly body. In particular embodiments, the bore 139 may include two sections (as shown in FIGs. 4A and 4B) with different radius. The first section of the bore 139 may receive a shaft on which the main roller 136 is installed and the second section of the bore 139 may receive the latching axle assembly 14. The first section of the bore 139 may have a slightly larger radius than the second section, and the two bore sections may share the same center axle.

[0076] The latching axle assembly 14 may have at least one latching mechanism including a number of latch pins, as will be discussed further below. The shaft bushing 146 ACTIVE 512643856.1ATTORNEY DOCKET PATENT APPLICATION 006976.2304 21 of 36 may have a width substantially equal to the length of the second latch pin 143. The second roller 135, which is a switchable roller, may be installed on the shaft bushing 146. The third latch pin 144 may have a length substantially equal to the inner length of the second latch receiving structure 149, causing the second latch pin 143 to be aligned with the shaft bushing 146 when the three latch pins 122, 123 and 124 are pushed to the end where the second latch receiving structure 149 is located. The inner length of the second receiving structure 149 may refer to the distance between the inner end wall of a first end of the first receiving structure 150 and the other end that faces the shaft bushing 146 of the inner rocker arm body 151. In contrast, the first latch pin 142 may have a length that is shorter than the inner length of the first latch receiving structure 150, so that when the three latch pins 142, 143, and 144 are pushed to the end of the first latch receiving structure 150, the second latch pin 143 is not aligned with the shaft bushing 146, causing the latching axle assembly 14 to be latched (i.e., in latched mode).

[0077] In this embodiment, the latching axle assembly 14 may be in unlatched mode as the normal or default mode when the oil control valve (OCV) (not shown) is OFF, and the control oil is not pumped into the pressurized oil chamber 147 of the latching axle assembly 14. For example, in the default or normal mode, the latching axle assembly 14 may be in the unlatched mode as shown in FIG.4A, where the OCV is off, and the control oil is not pumped into the pressurized oil chamber 147 between the third latch pin 144 and the inner wall of the second latch receiving structure 149. Due to the preset spring force, the latching pin spring 141 may push the first latch pin 142, the second latch pin 143, and the third latch pin 144 to the other end of the latching axle assembly 14 where the second latch receiving structure 149 is located. The third latch pin 144 may be pushed to a hard stop position touching the end wall of the second latch receiving structure 149. The third latch pin 144 may have a protrusion on its end touching the inner wall of the second latch receiving structure 149 and leaving a space for the pressurized oil chamber 147 between the main end surface of the third latching pin 144 and the inner wall of the second latch receiving structure 149.

[0078] In this default unlatched mode, the second latch pin 143 may be aligned with the shaft bushing 146 and the second roller 135 may be deactivated. The second latch pin 143, the shaft bushing 146, and the second roller 135 may move with the inner arm body and rotate around the pivot axle (114 in FIG.2B) against the lost motion spring force, as actuated by the cam force applied to the second roller 135. The second roller 135, which is installed on the shaft bushing 146, may receive the cam force from the cam (e.g., 172 in FIG.1C) that interfaces ACTIVE 512643856.1ATTORNEY DOCKET PATENT APPLICATION 006976.2304 22 of 36 with the second roller 135. When the cam that interfaces with the second roller 135 exerts an upward cam force, the inner arm body including the second latch pin 143, the shaft bushing 146, and the second roller 135 may be pushed upward by the cam force. As a result of the upward force, the inner arm body may rotate around the pivot axle (114 in FIG. 2B) and the lost motion spring (111 in FIGs. 2A and 2B) may be suppressed. As a result of motion of the lost motion spring assembly, the cam force from the cam that interfaces with the second roller 135 may not be transferred to the main body of the rocker arm assembly. The motion of the rocker arm assembly 16 may not follow the cam profile of the cam that interfaces with the second roller 135. The cam lift from the cam that interfaces with the second roller 135 may be therefore absorbed by the lost motion spring, rather than being transferred to the valve end, and the rocker arm assembly 16 may receive the transfer lift only from the other cam that interfaces with the first roller 136.

[0079] FIG.4B illustrates a cut-away perspective view 400B of the variable valve lift rocker arm assembly 16 with roller deactivation, showing the inner structure of the latching axle assembly 14 in a latched mode. The pressurized oil chamber 147 may be configured to hold the control oil. When the OCV is ON, the control oil may be pumped into the pressurized oil chamber 147 to push the latch pins 142, 143, and 144 to the latched positions, overcoming the force of the latch pin spring 141. The third latch pin 144 may serve as a piston to receive force from the control oil in the pressurized oil chamber 147 and to push the other two latch pins 142 and 143 to the other end where the latch pin spring 141 is located. The force on the third latch pin 144 from the control oil may overcome the force of the latch pin spring 141 to push the other two latch pins 143 and 142 toward the end where the latch pin spring 141 is located. The first latch pin 142 may have a length shorter than the inner length of the first latch receiving structure 150 and may be pushed to a hard stop position touching the end wall of the first latch receiving structure 150. As a result, the second latch pin 143 may be mis-aligned with the shaft bushing 146 on which the second roller 135 is installed. The second latch pin 143 and the third latch pin 144 may cause the latching axle assembly 14 to be latched. In the latched mode, the second and third latch pins 143 and 144 may latch the inner and outer rocker together, causing the cam force applied on the second roller 125 to be transferred to the outer rocker body. As a result, the outer rocker arm body may transfer a combination of the lifts from the first cam interfacing with the main roller 106 and the second cam interfacing with the ACTIVE 512643856.1ATTORNEY DOCKET PATENT APPLICATION 006976.2304 23 of 36 second roller 115 to the valve end, causing the rocker arm to follow a combined cam profile of the first and second cams.

[0080] In this embodiment as shown in FIGs.4A and 4B, to switch from the latched mode to the unlatched mode, the OCV may be turned off, causing the control oil in the pressurized oil chamber 147 to lose the pressure and be pushed out of the pressurized oil chamber 147. When the second roller 135 does not receive the upward pushing force from the cam that interfaces with the second roller 135 (e.g., because the cam has rotated to a position that its short cam end faces the second roller 135), the lost motion spring (not shown) may push back the inner arm body to rotate around the pivot axle, until the retainer latch pin (119 in FIG. 1C) hits the top surface of the hard stop structure (113 in FIG. 1C). As discussed above, the hard stop structure (113 in FIG.1C) may provide a hard stop position for the inner rocker arm body 151 and cause the second latch pin 143 to be at a position that is aligned with the first latch pin 142, and the third lath pin 144 along the shared center axle (being ready for moving along the shared axle to switch to the latched mode). Because the control oil in the pressured oil chamber 147 is pushed out of the pressurized oil chamber 147, the latch pin string 131 may push the first latch pin 142, the second latch pin 143, and the third latch pin 144 (which are aligned along the shared center axle) to the other end of the latching axle assembly 14 where the second latch receiving structure 149 is located. As a result, the latching axle assembly 14 may be unlatched as shown in FIG.4A. The unlatched mode may allow the lost motion spring to absorb the cam force from the cam that interfaces with the second roller 135, and prevent the cam force from being transferred to the valve end of the rocker arm assembly 16. In the unlatched mode, the motion of the outer rocker arm body of the rocker arm assembly 16 may follow the cam profile of the cam that interfaces with the first roller 136 only.

[0081] The embodiment as illustrated in FIGs.3A and 3B may have the latched mode as the normal or default mode when the OCV is OFF and there is substantially no control oil in the pressurized oil chamber 127. However, the embodiment as illustrated in FIGs. 4A and 4B may have the unlatched mode as the normal or default mode when the OCV is OFF and there is substantially no control oil in the pressurized oil chamber 147. The embodiment as illustrated in FIGs. 4A and 4B may have a first latch pin 142 which has a shorter length than the first latch pin 122 in the embodiment as illustrated in FIGs. 3A and 3B and may have a second latch pin 144 which is longer than the second latch pin 124 in the embodiment as ACTIVE 512643856.1ATTORNEY DOCKET PATENT APPLICATION 006976.2304 24 of 36 illustrated in FIGs. 3A and 3B, to allow the second latch pin 143 to be aligned with the shaft bushing 146 in the default or normal mode.

[0082] However, it is notable that the embodiment illustrated in FIGs. 4A and 4B is only one of the possible ways to achieve the default unlatched mode and an ordinary skill in the art will understand that there are other possible ways to achieve the default unlatched mode. For example, from the design as illustrated in FIGs.3A and 3B, the outer rocker arm body may be redesigned to have the inner rocker arm body 151 and the shaft bushing 126 to be aligned to the second latch pin 143 in a position when the OCV is OFF and there is substantially no control oil in the pressurized oil chamber 127, as illustrated in FIG. 3A, so that the latching axle assembly 12 may be in unlatched mode in the default or normal mode when the OCV is OFF. In this design, the length of the first and third latch pins 122 and 124 may be kept the same length as in the embodiment illustrated in FIG.3A and 3B. As another example to achieve the default latched mode, from the design as illustrated in FIGs. 4A and 4B, the outer rocker arm body may be redesigned to have the inner rocker arm body 151 and the shaft bushing 146 to be aligned to the second latch pin 143 in a position when the OCV is ON and there is control oil in the pressurized oil chamber 147, as illustrated in FIG. 4B, so that the latching axle assembly 14 may be in unlatched mode when the OCV is ON and in the latched mode in the default or normal mode when the OCV is OFF. In this design, the length of the first and third latch pins 142 and 144 may be kept the same length as in the embodiment illustrated in FIG. 4A and 4B. The cut-away perspective views as illustrated in FIGs. 3A-3B and 4A-4B may correspond to the cut line of 1-1 as illustrated in FIG. 1C for different embodiments of the rocker arm assembly 13.

[0083] Generally, when a cam mounted on a camshaft rotates, it may either directly or indirectly, exert pressure or force on a roller that interfaces with the cam. The profile of the cam may include lobes corresponding to valve lift events. The cam base circle position may correspond to a portion of the cam profile where there are no lobes and the pressure exerted by the cam on a roller, directly or indirectly, is at a minimum level. The cam lift mode position may correspond to a portion of the cam profile where there are cam lobes and the pressure exerted by the cam on a roller, directly or indirectly, is greater than the pressure exerted by the cam in cam base circle position to cause the valve end to move one or more affiliated valve.

[0084] Referring to FIG.1C, in particular embodiments, the rocker arm assembly 13 may have a main roller 106 that is fixed to the rocker arm body 103 and a switchable roller 115 ACTIVE 512643856.1ATTORNEY DOCKET PATENT APPLICATION 006976.2304 25 of 36 that can be activated or deactivated by the latching axle assembly 12. The rocker arm assembly 14 using the deactivating roller technology may be employed to modulate the intake valve to achieve either early or late valve closing. For example, the rocker arm assembly 13 may be used for LIVC (late intake valve closing) which makes effective compression ratio lower than expansion ratio, increasing efficiency while increasing exhaust temperature. The rocker arm assembly 13 may use the deactivating roller technology enables full switch in^one cam revolution and high lift fidelity.

[0085] FIG. 5A shows a plot 500A of valve lift over the cam angle for the latch assembly in the unlatched mode. Referring to FIG. 1C and FIGs. 2A-2B, the cam 171 that interfaces with the main roller 106 may be referred to as the main cam and the cam 172 that interfaces with the switchable roller 115 may be referred to as the secondary cam. In particular embodiments, the secondar cam 172 may have a larger cam lobe for at least a portion of the cam 172, comparing to the main cam 171. The main cam 171 may have a first cam profile used to control the main intake and the secondary cam 172 may have a second cam profile that is different from the first cam profile and may be used to provide a secondary lift for the late intake valve closing (LIVC). In the unlatched mode, the cam force from the secondary cam 172 may be absorbed by the lost motion spring 111 when the inner rocker arm body 112 rotates around the pivot axle 114. As a result, the cam profile of the main cam 171 may control the motion of the outer rocker arm body 103 and the valve end 181. When the latch assembly 12 is in the unlatched mode, the valve lift over the cam angle of the main cam 171 may be illustrated in FIG. 5A by the solid line. The dash line in FIG. 5A illustrates the valve lift as controlled by the secondary cam 172 if the motion of the rocker arm assembly 13 is only controlled by the secondary cam 172. The solid line in FIG. 5A may correspond to the cam lobe of the main cam 171 and the dash line in FIG.5A may correspond to the cam lobe of the secondary cam 172.

[0086] FIG. 5B shows a plot 500B of valve lift over the cam angle for the latch assembly in the latched mode. When the second roller 115 is activated by latching the latch pins in the latching axle assembly 12, the inner rocker arm body 112 may be mechanically latched and thus fixed to the outer rocker arm body 103 and other portions of the rocker arm assembly 13. As a result, the inner rocker arm body 112 may move together with the outer rocker arm body 103 as a unitary body to rotate around the shaft (not shown) seated in the shaft bore 104. The rotation force from the secondary cam 172 may be fully transferred to the outer ACTIVE 512643856.1ATTORNEY DOCKET PATENT APPLICATION 006976.2304 26 of 36 rocker arm body 103 and the valve end 181 of the rocker arm assembly 13, causing the motion of the outer rocker arm body 103 and the valve end 181 to follow a combined cam profile of the first cam profile of the main cam 171 and the second profile of the secondary cam 172. In particular, the valve lift, as illustrated by the solid line in FIG. 5B, may first follow the cam profile of the main cam 171 in the first stage (before A point) because during this stage the main cam 171 controls the motion of the rocker arm body 103 through the main roller. At the A point in FIG. 5B, the secondary cam 172 may start to touch the switchable roller 115 and because the second cam 172 may have a larger cam lobe for this portion than the main cam 171, the secondary cam 172 may control the rest of the motion of the rocker arm body 103 and the valve lift, as shown by the solid bold line in FIG.5B. As result, the secondary cam 172 may provide a secondary lift of LIVC as shown in FIG.5B.

[0087] In particular embodiments, the roller deactivating technology used in the rocker arm assembly 13 may be applied for cylinder deactivation (CDA). As an example, by deactivating the valves on one or more cylinders, the overall air / fuel ratio may be reduced. The amount of injected fuel may be at the similar levels as before, while the airflow is reduced proportionally to the number of deactivated cylinders. This may increase the exhaust temperatures and ultimately to improve emissions through improved catalyst efficiency. Simultaneously, the fuel efficiency may be improved for maximizing the cylinder deactivation while maintaining acceptable noise, vibration, and harshness (NVH) by, for example, deactivating variable numbers of cylinders depending on the engine's speed and load. The deactivation of a cylinder may be achieved by switching the associated inner rocker arm assembly into the unlatched mode so that the cam force may be absorbed by the associated lost motion spring, rather than being transferred to the outer rocker arm body.

[0088] FIG. 6 illustrates a perspective view 600 of a variable valve lift rocker arm assembly 16 with roller deactivation wherein two rollers can be deactivated. The first inner rocker assembly 163 (which includes the lost motion spring assembly, the inner rocker arm body, the shaft bushing, and the switchable roller) may be duplicated or a mirror image of the second inner rocker assembly 164 (which includes the lost motion spring assembly, the inner rocker arm body, the shaft bushing, and the switchable roller). Each of the first and second inner rocker assembly 163 and 164 may include a latching axle assembly (not shown) similar to the latching axle assembly as described above (e.g., the embodiments as illustrated in FIGs. 3A-3B or FIGs.4A-4B). In this embodiment, either the main roller or the second roller may be ACTIVE 512643856.1ATTORNEY DOCKET PATENT APPLICATION 006976.2304 27 of 36 latched or unlatched, singly or jointly. This may enable four distinct lift combinations including (1) the main roller latched with the second roller unlatched; (2) the main roller unlatched with the second roller latched; (3) both the main roller and second roller latched which allows for a “double lift” or “ghost lift”; or (4) both the main roller and second roller unlatched to allow for cylinder deactivation.

[0089] While the above embodiments describe an outer rocker arm body with a first valve end and a second valve end, the embodiments may be modified to allow for fewer or additional valve ends as may be required by design parameters. Similarly, while the above embodiments describe a rocker arm assembly with a first roller, and a second roller, the rocker arm assembly may be modified to allow for fewer or additional rollers, any combination of which may be capable of latching and unlatching. Other implementations will be apparent to those skilled in the art from consideration of the specification and practice of the examples disclosed herein.

[0090] In particular embodiments, a variable valve lift rocker arm assembly may include an outer rocker arm body comprising a valve end and a cam end. The outer rocker arm body may be configured to rotate around a first axle of the outer rocker arm body. The variable valve lift rocker arm assembly may include an inner rocker arm body configured to selectively and operatively latch to the outer rocker arm body through a latching assembly. The latching assembly may comprise one or more latch pins actuated by a first actuating assembly and a second actuating assembly to switch between a latched mode and an unlatched mode. In the latched mode, relative motion between the inner rocker arm body and the outer rocker arm body may be locked. In the unlatched mode, the relative motion between the inner rocker arm body and the outer rocker arm body is permitted.

[0091] In particular embodiments, the inner rocker arm body may be configured to rotate around the first axle with the outer rocker arm body in the latched mode.

[0092] In particular embodiments, the inner rocker arm body may be configured to rotate around a second axle of the outer rocker arm body in the unlatched mode.

[0093] In particular embodiments, the first actuating assembly may exert a first force pushing the one or more latch pins toward a first direction. The second actuating assembly may exert a second force pushing the one or more latch pins toward a second direction which is opposite to the first direction. ACTIVE 512643856.1ATTORNEY DOCKET PATENT APPLICATION 006976.2304 28 of 36

[0094] In particular embodiments, the one or more latch pins may comprise a first latch pin, a second latch pin, and a third latch pin. The first actuating assembly may comprise a latch pin spring. The second actuating assembly may comprise a hydraulic, mechanical or pneumatic device.

[0095] In particular embodiments, the cam end may comprise a first bore configured to seat (1) a first latch receiving structure configured to receive the first latch pin, and (2) a second latch receiving structure configured to receive the third latch pin. The first latch pin may have a length equals to an inner length of the first latch receiving structure.

[0096] In particular embodiments, the inner rocker arm body may comprise a second bore configured to receive a shaft bushing, wherein a switchable roller is installed on external surface of the shaft bushing and is configured to engage with a cam. The shaft bushing may be configured to receive the second latch pin within the shaft bushing. The second latch pin may have a length equal to that of the shaft bushing.

[0097] In particular embodiments, the switchable roller may be is configured to suppress a lost motion spring when the latching assembly is in the unlatched model. The lost motion spring may be configured to absorb cam force received by the switchable roller.

[0098] In particular embodiments, the latching assembly may be configured to be in the latched mode by default.

[0099] In particular embodiments, a variable valve lift rocker arm assembly may include an outer rocker arm body comprising a valve end and a cam end. The outer rocker arm body may be configured to rotate around a first axle of the outer rocker arm body, and the cam end comprises a first bore. An inner rocker arm body may be coupled to the outer rocker arm body and configured to pivot around the first axle or a second axle. The inner rocker arm body may comprise a second bore and an interface for engaging a cam. A latching assembly may be disposed within the first bore and the second bore. The latching assembly may comprise one or more latch pins, a first actuation mechanism configured to exert a first force to push the one or more latch pins in a first direction to a latched position, at which the one or more latch pins prevent relative motion between the inner rocker arm body and the outer rocker arm body, and a second actuation mechanism configured to exert a second force push the one or more latch pins in a second direction opposite to the first direction to an unlatched position, at which the latching assembly allows relative motion between the inner rocker arm body and the outer rocker arm body. ACTIVE 512643856.1ATTORNEY DOCKET PATENT APPLICATION 006976.2304 29 of 36

[0100] In particular embodiments, the interface for engaging the cam may comprise a switchable roller or a curved surface.

[0101] In particular embodiments, the one or more latch pins may comprise a first latch pin, a second latch pin, and a third latch pin. The first bore may be configured to seat (1) a first latch receiving structure configured to receive the first latch pin, and (2) a second latch receiving structure configured to receive the third latch pin, and wherein the first latch pin has a length equals to an inner length of the first latch receiving structure.

[0102] In particular embodiments, the second bore may be configured to receive a shaft bushing. A switchable roller may be installed on external surface of the shaft bushing and is configured to engage with a cam. The shaft bushing may be configured to receive the second latch pin within the shaft bushing. The second latch pin may have a length equal to that of the shaft bushing.

[0103] In particular embodiments, the switchable roller is configured to suppress a lost motion spring when the one or more latch pins are at the unlatched position, and wherein the lost motion spring is configured to absorb cam force received by the switchable roller.

[0104] In particular embodiments, a variable valve lift rocker arm assembly may comprise an outer rocker arm body comprising a valve end and a cam end. The variable valve lift rocker arm assembly may comprise an outer rocker arm body configured to rotate around a first axle of the outer rocker arm body. The variable valve lift rocker arm assembly may comprise an inner rocker arm body configured to (1) rotate around the first axle or a second axle of the outer rocker arm body and (2) selectively and operatively latch to the outer rocker arm body through a latching assembly. The latching assembly may comprise a first latch pin actuated by a latch pin spring, a second latch pin, and a third latch pin driven by a hydraulic, mechanical or pneumatic force. The latching assembly may be configured to have a latched mode in which the inner rocker arm body and the outer rocker arm body move as a unitary body. The latching assembly may be configured to have an unlatched mode in which the inner rocker arm body is permitted to rotate around the second axle while the outer rocker arm body rotates around the first axle.

[0105] In particular embodiments, the cam end may comprise a first bore configured to seat (1) a first latch receiving structure configured to receive the first latch pin, and (2) a second latch receiving structure configured to receive the third latch pin, and wherein the first latch pin has a length equals to an inner length of the first latch receiving structure. ACTIVE 512643856.1ATTORNEY DOCKET PATENT APPLICATION 006976.2304 30 of 36

[0106] In particular embodiments, the inner rocker arm body may comprise a second bore configured to receive a shaft bushing. A switchable roller may be installed on external surface of the shaft bushing and is configured to engage with a cam. The shaft bushing may be configured to receive the second latch pin within the shaft bushing, and wherein the second latch pin has a length equal to that of the shaft bushing.

[0107] In particular embodiments, the switchable roller may be configured to suppress a lost motion spring when the latching assembly is in the unlatched mode. The lost motion spring may be configured to absorb cam force received by the switchable roller.

[0108] In particular embodiments, the first latch pin, the second latch pin, and the third latch pin may be configured to move between a latched position and an unlatch position as actuated by the latch pin spring and driven by the hydraulic, mechanical or pneumatic force.

[0109] In particular embodiments, the inner rocker arm body may be configured to rotate around the second axle when the latching assembly is in the unlatched mode. The inner rocker arm body may be configured to rotate around the first axle when the latching assembly is in the latched mode.

[0110] It is to be understood that both the foregoing general description and the detailed description are exemplary and explanatory only and are not restrictive of the claimed invention. ACTIVE 512643856.1

Claims

ATTORNEY DOCKET PATENT APPLICATION 006976.2304 31 of 36 WHAT IS CLAIMED IS:

1. A variable valve lift rocker arm assembly comprising: an outer rocker arm body comprising a valve end and a cam end, wherein the outer rocker arm body is configured to rotate around a first axle of the outer rocker arm body; and an inner rocker arm body configured to selectively and operatively latch to the outer rocker arm body through a latching assembly, wherein: the latching assembly comprises one or more latch pins actuated by a first actuating assembly and a second actuating assembly to switch between a latched mode and an unlatched mode, wherein; in the latched mode, relative motion between the inner rocker arm body and the outer rocker arm body is locked; and in the unlatched mode, the relative motion between the inner rocker arm body and the outer rocker arm body is permitted.

2. The variable valve lift rocker arm assembly of Claim 1, wherein the inner rocker arm body is configured to rotate around the first axle with the outer rocker arm body in the latched mode.

3. The variable valve lift rocker arm assembly of Claim 1, wherein the inner rocker arm body is configured to rotate around a second axle of the outer rocker arm body in the unlatched mode.

4. The variable valve lift rocker arm assembly of Claim 1, wherein the first actuating assembly exerts a first force pushing the one or more latch pins toward a first direction, and wherein the second actuating assembly exerts a second force pushing the one or more latch pins toward a second direction which is opposite to the first direction.

5. The variable valve lift rocker arm assembly of Claim 1, wherein the one or more latch pins comprises a first latch pin, a second latch pin, and a third latch pin, wherein the first actuating assembly comprises a latch pin spring, and wherein the second actuating assembly comprises a hydraulic, mechanical or pneumatic device. ACTIVE 512643856.1ATTORNEY DOCKET PATENT APPLICATION 006976.2304 32 of 36 6. The variable valve lift rocker arm assembly of Claim 5, wherein the cam end comprises a first bore configured to seat (1) a first latch receiving structure configured to receive the first latch pin, and (2) a second latch receiving structure configured to receive the third latch pin, and wherein the first latch pin has a length equals to an inner length of the first latch receiving structure.

7. The variable valve lift rocker arm assembly of Claim 6, wherein the inner rocker arm body comprises a second bore configured to receive a shaft bushing, wherein a switchable roller is installed on external surface of the shaft bushing and is configured to engage with a cam, wherein the shaft bushing is configured to receive the second latch pin within the shaft bushing, and wherein the second latch pin has a length equal to that of the shaft bushing.

8. The variable valve lift rocker arm assembly of Claim 7, wherein the switchable roller is configured to suppress a lost motion spring when the latching assembly is in the unlatched mode, and wherein the lost motion spring is configured to absorb cam force received by the switchable roller.

9. The variable valve lift rocker arm assembly of Claim 7, wherein the latching assembly is configured to be in the latched mode by default.

10. A variable valve lift rocker arm assembly comprising: an outer rocker arm body comprising a valve end and a cam end, wherein the outer rocker arm body is configured to rotate around a first axle of the outer rocker arm body, and the cam end comprises a first bore; an inner rocker arm body coupled to the outer rocker arm body and configured to pivot around the first axle or a second axle, wherein the inner rocker arm body comprises a second bore and an interface for engaging a cam; and a latching assembly disposed within the first bore and the second bore, wherein the latching assembly comprises: one or more latch pins; a first actuation mechanism configured to exert a first force to push the one or more latch pins in a first direction to a latched position, at which the one or more latch ACTIVE 512643856.1ATTORNEY DOCKET PATENT APPLICATION 006976.2304 33 of 36 pins prevent relative motion between the inner rocker arm body and the outer rocker arm body; and a second actuation mechanism configured to exert a second force push the one or more latch pins in a second direction opposite to the first direction to an unlatched position, at which the latching assembly allows relative motion between the inner rocker arm body and the outer rocker arm body.

11. The variable valve lift rocker arm assembly of Claim 10, wherein the interface for engaging the cam comprises a switchable roller or a curved surface.

12. The variable valve lift rocker arm assembly of Claim 10, wherein the one or more latch pins comprises a first latch pin, a second latch pin, and a third latch pin, and wherein the first bore is configured to seat (1) a first latch receiving structure configured to receive the first latch pin, and (2) a second latch receiving structure configured to receive the third latch pin, and wherein the first latch pin has a length equals to an inner length of the first latch receiving structure.

13. The variable valve lift rocker arm assembly of Claim 12, wherein the second bore is configured to receive a shaft bushing, wherein a switchable roller is installed on external surface of the shaft bushing and is configured to engage with a cam, wherein the shaft bushing is configured to receive the second latch pin within the shaft bushing, and wherein the second latch pin has a length equal to that of the shaft bushing.

14. The variable valve lift rocker arm assembly of Claim 13, wherein the switchable roller is configured to suppress a lost motion spring when the one or more latch pins are at the unlatched position, and wherein the lost motion spring is configured to absorb cam force received by the switchable roller.

15. A variable valve lift rocker arm assembly comprising: an outer rocker arm body comprising a valve end and a cam end, wherein the outer rocker arm body is configured to rotate around a first axle of the outer rocker arm body; and ACTIVE 512643856.1ATTORNEY DOCKET PATENT APPLICATION 006976.2304 34 of 36 an inner rocker arm body configured to (1) rotate around the first axle or a second axle of the outer rocker arm body and (2) selectively and operatively latch to the outer rocker arm body through a latching assembly, wherein: the latching assembly comprises a first latch pin actuated by a latch pin spring, a second latch pin, and a third latch pin driven by a hydraulic, mechanical or pneumatic force; the latching assembly is configured to have a latched mode in which the inner rocker arm body and the outer rocker arm body move as a unitary body; and the latching assembly is configured to have an unlatched mode in which the inner rocker arm body is permitted to rotate around the second axle while the outer rocker arm body rotates around the first axle.

16. The variable valve lift rocker arm assembly of Claim 15, wherein the cam end comprises a first bore configured to seat (1) a first latch receiving structure configured to receive the first latch pin, and (2) a second latch receiving structure configured to receive the third latch pin, and wherein the first latch pin has a length equals to an inner length of the first latch receiving structure.

17. The variable valve lift rocker arm assembly of Claim 16, wherein the inner rocker arm body comprises a second bore configured to receive a shaft bushing, wherein a switchable roller is installed on external surface of the shaft bushing and is configured to engage with a cam, wherein the shaft bushing is configured to receive the second latch pin within the shaft bushing, and wherein the second latch pin has a length equal to that of the shaft bushing.

18. The variable valve lift rocker arm assembly of Claim 17, wherein the switchable roller is configured to suppress a lost motion spring when the latching assembly is in the unlatched mode, and wherein the lost motion spring is configured to absorb cam force received by the switchable roller.

19. The variable valve lift rocker arm assembly of Claim 15, wherein the first latch pin, the second latch pin, and the third latch pin are configured to move between a latched position and an unlatch position as actuated by the latch pin spring and driven by the hydraulic, mechanical or pneumatic force. ACTIVE 512643856.1ATTORNEY DOCKET PATENT APPLICATION 006976.2304 35 of 36 20. The variable valve lift rocker arm assembly of Claim 15, wherein the inner rocker arm body is configured to rotate around the second axle when the latching assembly is in the unlatched mode, and wherein the inner rocker arm body is configured to rotate around the first axle when the latching assembly is in the latched mode. ACTIVE 512643856.1

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